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rfc:rfc2744

Network Working Group J. Wray Request for Comments: 2744 Iris Associates Obsoletes: 1509 January 2000 Category: Standards Track

        Generic Security Service API Version 2 : C-bindings

Status of this Memo

 This document specifies an Internet standards track protocol for the
 Internet community, and requests discussion and suggestions for
 improvements.  Please refer to the current edition of the "Internet
 Official Protocol Standards" (STD 1) for the standardization state
 and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

 Copyright (C) The Internet Society (2000).  All Rights Reserved.

Abstract

 This document specifies C language bindings for Version 2, Update 1
 of the Generic Security Service Application Program Interface (GSS-
 API), which is described at a language-independent conceptual level
 in RFC-2743 [GSSAPI].  It obsoletes RFC-1509, making specific
 incremental changes in response to implementation experience and
 liaison requests.  It is intended, therefore, that this memo or a
 successor version thereof will become the basis for subsequent
 progression of the GSS-API specification on the standards track.
 The Generic Security Service Application Programming Interface
 provides security services to its callers, and is intended for
 implementation atop a variety of underlying cryptographic mechanisms.
 Typically, GSS-API callers will be application protocols into which
 security enhancements are integrated through invocation of services
 provided by the GSS-API. The GSS-API allows a caller application to
 authenticate a principal identity associated with a peer application,
 to delegate rights to a peer, and to apply security services such as
 confidentiality and integrity on a per-message basis.

Wray Standards Track [Page 1] RFC 2744 GSS-API V2: C-bindings January 2000

1. Introduction

 The Generic Security Service Application Programming Interface
 [GSSAPI] provides security services to calling applications.  It
 allows a communicating application to authenticate the user
 associated with another application, to delegate rights to another
 application, and to apply security services such as confidentiality
 and integrity on a per-message basis.
 There are four stages to using the GSS-API:
 a) The application acquires a set of credentials with which it may
    prove its identity to other processes. The application's
    credentials vouch for its global identity, which may or may not be
    related to any local username under which it may be running.
 b) A pair of communicating applications establish a joint security
    context using their credentials.  The security context is a pair
    of GSS-API data structures that contain shared state information,
    which is required in order that per-message security services may
    be provided.  Examples of state that might be shared between
    applications as part of a security context are cryptographic keys,
    and message sequence numbers.  As part of the establishment of a
    security context, the context initiator is authenticated to the
    responder, and may require that the responder is authenticated in
    turn.  The initiator may optionally give the responder the right
    to initiate further security contexts, acting as an agent or
    delegate of the initiator.  This transfer of rights is termed
    delegation, and is achieved by creating a set of credentials,
    similar to those used by the initiating application, but which may
    be used by the responder.
    To establish and maintain the shared information that makes up the
    security context, certain GSS-API calls will return a token data
    structure, which is an opaque data type that may contain
    cryptographically protected data.  The caller of such a GSS-API
    routine is responsible for transferring the token to the peer
    application, encapsulated if necessary in an application-
    application protocol.  On receipt of such a token, the peer
    application should pass it to a corresponding GSS-API routine
    which will decode the token and extract the information, updating
    the security context state information accordingly.

Wray Standards Track [Page 2] RFC 2744 GSS-API V2: C-bindings January 2000

 c) Per-message services are invoked to apply either:
    integrity and data origin authentication, or confidentiality,
    integrity and data origin authentication to application data,
    which are treated by GSS-API as arbitrary octet-strings.  An
    application transmitting a message that it wishes to protect will
    call the appropriate GSS-API routine (gss_get_mic or gss_wrap) to
    apply protection, specifying the appropriate security context, and
    send the resulting token to the receiving application.  The
    receiver will pass the received token (and, in the case of data
    protected by gss_get_mic, the accompanying message-data) to the
    corresponding decoding routine (gss_verify_mic or gss_unwrap) to
    remove the protection and validate the data.
 d) At the completion of a communications session (which may extend
    across several transport connections), each application calls a
    GSS-API routine to delete the security context.  Multiple contexts
    may also be used (either successively or simultaneously) within a
    single communications association, at the option of the
    applications.

2. GSS-API Routines

    This section lists the routines that make up the GSS-API, and
    offers a brief description of the purpose of each routine.
    Detailed descriptions of each routine are listed in alphabetical
    order in section 5.
 Table 2-1  GSS-API Credential-management Routines
 Routine                Section              Function
 -------                -------              --------
 gss_acquire_cred           5.2  Assume a global identity; Obtain
                                 a GSS-API credential handle for
                                 pre-existing credentials.
 gss_add_cred               5.3  Construct credentials
                                 incrementally
 gss_inquire_cred           5.21 Obtain information about a
                                 credential
 gss_inquire_cred_by_mech   5.22 Obtain per-mechanism information
                                 about a credential.
 gss_release_cred           5.27 Discard a credential handle.

Wray Standards Track [Page 3] RFC 2744 GSS-API V2: C-bindings January 2000

 Table 2-2  GSS-API Context-Level Routines
 Routine                 Section              Function
 -------                 -------              --------
 gss_init_sec_context       5.19 Initiate a security context with
                                 a peer application
 gss_accept_sec_context     5.1  Accept a security context
                                 initiated by a
                                 peer application
 gss_delete_sec_context     5.9  Discard a security context
 gss_process_context_token  5.25 Process a token on a security
                                 context from a peer application
 gss_context_time           5.7  Determine for how long a context
                                 will remain valid
 gss_inquire_context        5.20 Obtain information about a
                                 security context
 gss_wrap_size_limit        5.34 Determine token-size limit for
                                 gss_wrap on a context
 gss_export_sec_context     5.14 Transfer a security context to
                                 another process
 gss_import_sec_context     5.17 Import a transferred context
 Table 2-3  GSS-API Per-message Routines
 Routine                 Section              Function
 -------                 -------              --------
 gss_get_mic                5.15 Calculate a cryptographic message
                                 integrity code (MIC) for a
                                 message; integrity service
 gss_verify_mic             5.32 Check a MIC against a message;
                                 verify integrity of a received
                                 message
 gss_wrap                   5.33 Attach a MIC to a message, and
                                 optionally encrypt the message
                                 content;
                                 confidentiality service
 gss_unwrap                 5.31 Verify a message with attached
                                 MIC, and decrypt message content
                                 if necessary.

Wray Standards Track [Page 4] RFC 2744 GSS-API V2: C-bindings January 2000

 Table 2-4  GSS-API Name manipulation Routines
 Routine                 Section              Function
 -------                 -------              --------
 gss_import_name            5.16 Convert a contiguous string name
                                 to internal-form
 gss_display_name           5.10 Convert internal-form name to
                                 text
 gss_compare_name           5.6  Compare two internal-form names
 gss_release_name           5.28 Discard an internal-form name
 gss_inquire_names_for_mech 5.24 List the name-types supported by
                                 the specified mechanism
 gss_inquire_mechs_for_name 5.23 List mechanisms that support the
                                 specified name-type
 gss_canonicalize_name      5.5  Convert an internal name to an MN
 gss_export_name            5.13 Convert an MN to export form
 gss_duplicate_name         5.12 Create a copy of an internal name
 Table 2-5  GSS-API Miscellaneous Routines
 Routine                Section              Function
 -------                -------              --------
 gss_add_oid_set_member    5.4  Add an object identifier to
                                a set
 gss_display_status        5.11 Convert a GSS-API status code
                                to text
 gss_indicate_mechs        5.18 Determine available underlying
                                authentication mechanisms
 gss_release_buffer        5.26 Discard a buffer
 gss_release_oid_set       5.29 Discard a set of object
                                identifiers
 gss_create_empty_oid_set  5.8  Create a set containing no
                                object identifiers
 gss_test_oid_set_member   5.30 Determines whether an object
                                     identifier is a member of a set.
 Individual GSS-API implementations may augment these routines by
 providing additional mechanism-specific routines if required
 functionality is not available from the generic forms. Applications
 are encouraged to use the generic routines wherever possible on
 portability grounds.

Wray Standards Track [Page 5] RFC 2744 GSS-API V2: C-bindings January 2000

3. Data Types and Calling Conventions

 The following conventions are used by the GSS-API C-language
 bindings:

3.1. Integer types

 GSS-API uses the following integer data type:
 OM_uint32    32-bit unsigned integer
 Where guaranteed minimum bit-count is important, this portable data
 type is used by the GSS-API routine definitions.  Individual GSS-API
 implementations will include appropriate typedef definitions to map
 this type onto a built-in data type.  If the platform supports the
 X/Open xom.h header file, the OM_uint32 definition contained therein
 should be used; the GSS-API header file in Appendix A contains logic
 that will detect the prior inclusion of xom.h, and will not attempt
 to re-declare OM_uint32.  If the X/Open header file is not available
 on the platform, the GSS-API implementation should use the smallest
 natural unsigned integer type that provides at least 32 bits of
 precision.

3.2. String and similar data

 Many of the GSS-API routines take arguments and return values that
 describe contiguous octet-strings.  All such data is passed between
 the GSS-API and the caller using the gss_buffer_t data type.  This
 data type is a pointer to a buffer descriptor, which consists of a
 length field that contains the total number of bytes in the datum,
 and a value field which contains a pointer to the actual datum:
 typedef struct gss_buffer_desc_struct {
    size_t    length;
    void      *value;
 } gss_buffer_desc, *gss_buffer_t;
 Storage for data returned to the application by a GSS-API routine
 using the gss_buffer_t conventions is allocated by the GSS-API
 routine.  The application may free this storage by invoking the
 gss_release_buffer routine.  Allocation of the gss_buffer_desc object
 is always the responsibility of the application;  unused
 gss_buffer_desc objects may be initialized to the value
 GSS_C_EMPTY_BUFFER.

Wray Standards Track [Page 6] RFC 2744 GSS-API V2: C-bindings January 2000

3.2.1. Opaque data types

 Certain multiple-word data items are considered opaque data types at
 the GSS-API, because their internal structure has no significance
 either to the GSS-API or to the caller.  Examples of such opaque data
 types are the input_token parameter to gss_init_sec_context (which is
 opaque to the caller), and the input_message parameter to gss_wrap
 (which is opaque to the GSS-API).  Opaque data is passed between the
 GSS-API and the application using the gss_buffer_t datatype.

3.2.2. Character strings

 Certain multiple-word data items may be regarded as simple ISO
 Latin-1 character strings.  Examples are the printable strings passed
 to gss_import_name via the input_name_buffer parameter. Some GSS-API
 routines also return character strings.  All such character strings
 are passed between the application and the GSS-API implementation
 using the gss_buffer_t datatype, which is a pointer to a
 gss_buffer_desc object.
 When a gss_buffer_desc object describes a printable string, the
 length field of the gss_buffer_desc should only count printable
 characters within the string.  In particular, a trailing NUL
 character should NOT be included in the length count, nor should
 either the GSS-API implementation or the application assume the
 presence of an uncounted trailing NUL.

3.3. Object Identifiers

 Certain GSS-API procedures take parameters of the type gss_OID, or
 Object identifier.  This is a type containing ISO-defined tree-
 structured values, and is used by the GSS-API caller to select an
 underlying security mechanism and to specify namespaces.  A value of
 type gss_OID has the following structure:
 typedef struct gss_OID_desc_struct {
    OM_uint32   length;
    void        *elements;
 } gss_OID_desc, *gss_OID;
 The elements field of this structure points to the first byte of an
 octet string containing the ASN.1 BER encoding of the value portion
 of the normal BER TLV encoding of the gss_OID.  The length field
 contains the number of bytes in this value.  For example, the gss_OID
 value corresponding to {iso(1) identified-organization(3) icd-
 ecma(12) member-company(2) dec(1011) cryptoAlgorithms(7) DASS(5)},
 meaning the DASS X.509 authentication mechanism, has a length field
 of 7 and an elements field pointing to seven octets containing the

Wray Standards Track [Page 7] RFC 2744 GSS-API V2: C-bindings January 2000

 following octal values: 53,14,2,207,163,7,5. GSS-API implementations
 should provide constant gss_OID values to allow applications to
 request any supported mechanism, although applications are encouraged
 on portability grounds to accept the default mechanism.  gss_OID
 values should also be provided to allow applications to specify
 particular name types (see section 3.10).  Applications should treat
 gss_OID_desc values returned by GSS-API routines as read-only.  In
 particular, the application should not attempt to deallocate them
 with free().  The gss_OID_desc datatype is equivalent to the X/Open
 OM_object_identifier datatype[XOM].

3.4. Object Identifier Sets

 Certain GSS-API procedures take parameters of the type gss_OID_set.
 This type represents one or more object identifiers (section 2.3).  A
 gss_OID_set object has the following structure:
 typedef struct gss_OID_set_desc_struct {
    size_t    count;
    gss_OID   elements;
 } gss_OID_set_desc, *gss_OID_set;
 The count field contains the number of OIDs within the set.  The
 elements field is a pointer to an array of gss_OID_desc objects, each
 of which describes a single OID.  gss_OID_set values are used to name
 the available mechanisms supported by the GSS-API, to request the use
 of specific mechanisms, and to indicate which mechanisms a given
 credential supports.
 All OID sets returned to the application by GSS-API are dynamic
 objects (the gss_OID_set_desc, the "elements" array of the set, and
 the "elements" array of each member OID are all dynamically
 allocated), and this storage must be deallocated by the application
 using the gss_release_oid_set() routine.

3.5. Credentials

 A credential handle is a caller-opaque atomic datum that identifies a
 GSS-API credential data structure.  It is represented by the caller-
 opaque type gss_cred_id_t, which should be implemented as a pointer
 or arithmetic type.  If a pointer implementation is chosen, care must
 be taken to ensure that two gss_cred_id_t values may be compared with
 the == operator.
 GSS-API credentials can contain mechanism-specific principal
 authentication data for multiple mechanisms.  A GSS-API credential is
 composed of a set of credential-elements, each of which is applicable
 to a single mechanism.  A credential may contain at most one

Wray Standards Track [Page 8] RFC 2744 GSS-API V2: C-bindings January 2000

 credential-element for each supported mechanism. A credential-element
 identifies the data needed by a single mechanism to authenticate a
 single principal, and conceptually contains two credential-references
 that describe the actual mechanism-specific authentication data, one
 to be used by GSS-API for initiating contexts,  and one to be used
 for accepting contexts.  For mechanisms that do not distinguish
 between acceptor and initiator credentials, both references would
 point to the same underlying mechanism-specific authentication data.
 Credentials describe a set of mechanism-specific principals, and give
 their holder the ability to act as any of those principals. All
 principal identities asserted by a single GSS-API credential should
 belong to the same entity, although enforcement of this property is
 an implementation-specific matter.  The GSS-API does not make the
 actual credentials available to applications; instead a credential
 handle is used to identify a particular credential, held internally
 by GSS-API.  The combination of GSS-API credential handle and
 mechanism identifies the principal whose identity will be asserted by
 the credential when used with that mechanism.
 The gss_init_sec_context and gss_accept_sec_context routines allow
 the value GSS_C_NO_CREDENTIAL to be specified as their credential
 handle parameter.  This special credential-handle indicates a desire
 by the application to act as a default principal.  While individual
 GSS-API implementations are free to determine such default behavior
 as appropriate to the mechanism, the following default behavior by
 these routines is recommended for portability:
 gss_init_sec_context
    1) If there is only a single principal capable of initiating
       security contexts for the chosen mechanism that the application
       is authorized to act on behalf of, then that principal shall be
       used, otherwise
    2) If the platform maintains a concept of a default network-
       identity for the chosen mechanism, and if the application is
       authorized to act on behalf of that identity for the purpose of
       initiating security contexts, then the principal corresponding
       to that identity shall be used, otherwise
    3) If the platform maintains a concept of a default local
       identity, and provides a means to map local identities into
       network-identities for the chosen mechanism, and if the
       application is authorized to act on behalf of the network-
       identity image of the default local identity for the purpose of

Wray Standards Track [Page 9] RFC 2744 GSS-API V2: C-bindings January 2000

       initiating security contexts using the chosen mechanism, then
       the principal corresponding to that identity shall be used,
       otherwise
    4) A user-configurable default identity should be used.
 gss_accept_sec_context
    1) If there is only a single authorized principal identity capable
       of accepting security contexts for the chosen mechanism, then
       that principal shall be used, otherwise
    2) If the mechanism can determine the identity of the target
       principal by examining the context-establishment token, and if
       the accepting application is authorized to act as that
       principal for the purpose of accepting security contexts using
       the chosen mechanism, then that principal identity shall be
       used, otherwise
    3) If the mechanism supports context acceptance by any principal,
       and if mutual authentication was not requested, any principal
       that the application is authorized to accept security contexts
       under using the chosen mechanism may be used, otherwise
    4)A user-configurable default identity shall be used.
 The purpose of the above rules is to allow security contexts to be
 established by both initiator and acceptor using the default behavior
 wherever possible.  Applications requesting default behavior are
 likely to be more portable across mechanisms and platforms than ones
 that use gss_acquire_cred to request a specific identity.

3.6. Contexts

 The gss_ctx_id_t data type contains a caller-opaque atomic value that
 identifies one end of a GSS-API security context.  It should be
 implemented as a pointer or arithmetic type.  If a pointer type is
 chosen, care should be taken to ensure that two gss_ctx_id_t values
 may be compared with the == operator.
 The security context holds state information about each end of a peer
 communication, including cryptographic state information.

Wray Standards Track [Page 10] RFC 2744 GSS-API V2: C-bindings January 2000

3.7. Authentication tokens

 A token is a caller-opaque type that GSS-API uses to maintain
 synchronization between the context data structures at each end of a
 GSS-API security context.  The token is a cryptographically protected
 octet-string, generated by the underlying mechanism at one end of a
 GSS-API security context for use by the peer mechanism at the other
 end.  Encapsulation (if required) and transfer of the token are the
 responsibility of the peer applications.  A token is passed between
 the GSS-API and the application using the gss_buffer_t conventions.

3.8. Interprocess tokens

 Certain GSS-API routines are intended to transfer data between
 processes in multi-process programs.  These routines use a caller-
 opaque octet-string, generated by the GSS-API in one process for use
 by the GSS-API in another process.  The calling application is
 responsible for transferring such tokens between processes in an OS-
 specific manner.  Note that, while GSS-API implementors are
 encouraged to avoid placing sensitive information within interprocess
 tokens, or to cryptographically protect them, many implementations
 will be unable to avoid placing key material or other sensitive data
 within them.  It is the application's responsibility to ensure that
 interprocess tokens are protected in transit, and transferred only to
 processes that are trustworthy. An interprocess token is passed
 between the GSS-API and the application using the gss_buffer_t
 conventions.

3.9. Status values

 Every GSS-API routine returns two distinct values to report status
 information to the caller: GSS status codes and Mechanism status
 codes.

3.9.1. GSS status codes

 GSS-API routines return GSS status codes as their OM_uint32 function
 value.  These codes indicate errors that are independent of the
 underlying mechanism(s) used to provide the security service.  The
 errors that can be indicated via a GSS status code are either generic
 API routine errors (errors that are defined in the GSS-API
 specification) or calling errors (errors that are specific to these
 language bindings).
 A GSS status code can indicate a single fatal generic API error from
 the routine and a single calling error.  In addition, supplementary
 status information may be indicated via the setting of bits in the
 supplementary info field of a GSS status code.

Wray Standards Track [Page 11] RFC 2744 GSS-API V2: C-bindings January 2000

 These errors are encoded into the 32-bit GSS status code as follows:
    MSB                                                        LSB
    |------------------------------------------------------------|
    |  Calling Error | Routine Error  |    Supplementary Info    |
    |------------------------------------------------------------|
 Bit 31            24 23            16 15                       0
 Hence if a GSS-API routine returns a GSS status code whose upper 16
 bits contain a non-zero value, the call failed.  If the calling error
 field is non-zero, the invoking application's call of the routine was
 erroneous.  Calling errors are defined in table 5-1.  If the routine
 error field is non-zero, the routine failed for one of the routine-
 specific reasons listed below in table 5-2.  Whether or not the upper
 16 bits indicate a failure or a success, the routine may indicate
 additional information by setting bits in the supplementary info
 field of the status code. The meaning of individual bits is listed
 below in table 5-3.
 Table 3-1  Calling Errors
 Name                   Value in field           Meaning
 ----                   --------------           -------
 GSS_S_CALL_INACCESSIBLE_READ  1       A required input parameter
                                       could not be read
 GSS_S_CALL_INACCESSIBLE_WRITE 2       A required output parameter
                                        could not be written.
 GSS_S_CALL_BAD_STRUCTURE      3       A parameter was malformed

Wray Standards Track [Page 12] RFC 2744 GSS-API V2: C-bindings January 2000

 Table 3-2  Routine Errors
 Name                   Value in field           Meaning
 ----                   --------------           -------
 GSS_S_BAD_MECH                1       An unsupported mechanism
                                       was requested
 GSS_S_BAD_NAME                2       An invalid name was
                                       supplied
 GSS_S_BAD_NAMETYPE            3       A supplied name was of an
                                       unsupported type
 GSS_S_BAD_BINDINGS            4       Incorrect channel bindings
                                       were supplied
 GSS_S_BAD_STATUS              5       An invalid status code was
                                       supplied
 GSS_S_BAD_MIC GSS_S_BAD_SIG   6       A token had an invalid MIC
 GSS_S_NO_CRED                 7       No credentials were
                                       supplied, or the
                                       credentials were
                                       unavailable or
                                       inaccessible.
 GSS_S_NO_CONTEXT              8       No context has been
                                       established
 GSS_S_DEFECTIVE_TOKEN         9       A token was invalid
 GSS_S_DEFECTIVE_CREDENTIAL   10       A credential was invalid
 GSS_S_CREDENTIALS_EXPIRED    11       The referenced credentials
                                       have expired
 GSS_S_CONTEXT_EXPIRED        12       The context has expired
 GSS_S_FAILURE                13       Miscellaneous failure (see
                                       text)
 GSS_S_BAD_QOP                14       The quality-of-protection
                                       requested could not be
                                       provided
 GSS_S_UNAUTHORIZED           15       The operation is forbidden
                                       by local security policy
 GSS_S_UNAVAILABLE            16       The operation or option is
                                       unavailable
 GSS_S_DUPLICATE_ELEMENT      17       The requested credential
                                       element already exists
 GSS_S_NAME_NOT_MN            18       The provided name was not a
                                       mechanism name

Wray Standards Track [Page 13] RFC 2744 GSS-API V2: C-bindings January 2000

 Table 3-3  Supplementary Status Bits
 Name                   Bit Number           Meaning
 ----                   ----------           -------
 GSS_S_CONTINUE_NEEDED   0 (LSB)   Returned only by
                                   gss_init_sec_context or
                                   gss_accept_sec_context. The
                                   routine must be called again
                                   to complete its function.
                                   See routine documentation for
                                   detailed description
 GSS_S_DUPLICATE_TOKEN   1         The token was a duplicate of
                                   an earlier token
 GSS_S_OLD_TOKEN         2         The token's validity period
                                   has expired
 GSS_S_UNSEQ_TOKEN       3         A later token has already been
                                   processed
 GSS_S_GAP_TOKEN         4         An expected per-message token
                                   was not received
 The routine documentation also uses the name GSS_S_COMPLETE, which is
 a zero value, to indicate an absence of any API errors or
 supplementary information bits.
 All GSS_S_xxx symbols equate to complete OM_uint32 status codes,
 rather than to bitfield values.  For example, the actual value of the
 symbol GSS_S_BAD_NAMETYPE (value 3 in the routine error field) is
 3<<16.  The macros GSS_CALLING_ERROR(), GSS_ROUTINE_ERROR() and
 GSS_SUPPLEMENTARY_INFO() are provided, each of which takes a GSS
 status code and removes all but the relevant field.  For example, the
 value obtained by applying GSS_ROUTINE_ERROR to a status code removes
 the calling errors and supplementary info fields, leaving only the
 routine errors field.  The values delivered by these macros may be
 directly compared with a GSS_S_xxx symbol of the appropriate type.
 The macro GSS_ERROR() is also provided, which when applied to a GSS
 status code returns a non-zero value if the status code indicated a
 calling or routine error, and a zero value otherwise.  All macros
 defined by GSS-API evaluate their argument(s) exactly once.
 A GSS-API implementation may choose to signal calling errors in a
 platform-specific manner instead of, or in addition to the routine
 value;  routine errors and supplementary info should be returned via
 major status values only.
 The GSS major status code GSS_S_FAILURE is used to indicate that the
 underlying mechanism detected an error for which no specific GSS
 status code is defined.  The mechanism-specific status code will
 provide more details about the error.

Wray Standards Track [Page 14] RFC 2744 GSS-API V2: C-bindings January 2000

3.9.2. Mechanism-specific status codes

 GSS-API routines return a minor_status parameter, which is used to
 indicate specialized errors from the underlying security mechanism.
 This parameter may contain a single mechanism-specific error,
 indicated by a OM_uint32 value.
 The minor_status parameter will always be set by a GSS-API routine,
 even if it returns a calling error or one of the generic API errors
 indicated above as fatal, although most other output parameters may
 remain unset in such cases.  However, output parameters that are
 expected to return pointers to storage allocated by a routine must
 always be set by the routine, even in the event of an error, although
 in such cases the GSS-API routine may elect to set the returned
 parameter value to NULL to indicate that no storage was actually
 allocated.  Any length field associated with such pointers (as in a
 gss_buffer_desc structure) should also be set to zero in such cases.

3.10. Names

 A name is used to identify a person or entity.  GSS-API authenticates
 the relationship between a name and the entity claiming the name.
 Since different authentication mechanisms may employ different
 namespaces for identifying their principals, GSSAPI's naming support
 is necessarily complex in multi-mechanism environments (or even in
 some single-mechanism environments where the underlying mechanism
 supports multiple namespaces).
 Two distinct representations are defined for names:
 An internal form.  This is the GSS-API "native" format for names,
    represented by the implementation-specific gss_name_t type.  It is
    opaque to GSS-API callers.  A single gss_name_t object may contain
    multiple names from different namespaces, but all names should
    refer to the same entity.  An example of such an internal name
    would be the name returned from a call to the gss_inquire_cred
    routine, when applied to a credential containing credential
    elements for multiple authentication mechanisms employing
    different namespaces.  This gss_name_t object will contain a
    distinct name for the entity for each authentication mechanism.
    For GSS-API implementations supporting multiple namespaces,
    objects of type gss_name_t must contain sufficient information to
    determine the namespace to which each primitive name belongs.

Wray Standards Track [Page 15] RFC 2744 GSS-API V2: C-bindings January 2000

 Mechanism-specific contiguous octet-string forms.  A format
    capable of containing a single name (from a single namespace).
    Contiguous string names are always accompanied by an object
    identifier specifying the namespace to which the name belongs, and
    their format is dependent on the authentication mechanism that
    employs the name.  Many, but not all, contiguous string names will
    be printable, and may therefore be used by GSS-API applications
    for communication with their users.
 Routines (gss_import_name and gss_display_name) are provided to
 convert names between contiguous string representations and the
 internal gss_name_t type.  gss_import_name may support multiple
 syntaxes for each supported namespace, allowing users the freedom to
 choose a preferred name representation. gss_display_name should use
 an implementation-chosen printable syntax for each supported name-
 type.
 If an application calls gss_display_name(), passing the internal name
 resulting from a call to gss_import_name(), there is no guarantee the
 the resulting contiguous string name will be the same as the original
 imported string name.  Nor do name-space identifiers necessarily
 survive unchanged after a journey through the internal name-form.  An
 example of this might be a mechanism that authenticates X.500 names,
 but provides an algorithmic mapping of Internet DNS names into X.500.
 That mechanism's implementation of gss_import_name() might, when
 presented with a DNS name, generate an internal name that contained
 both the original DNS name and the equivalent X.500 name.
 Alternatively, it might only store the X.500 name.  In the latter
 case, gss_display_name() would most likely generate a printable X.500
 name, rather than the original DNS name.
 The process of authentication delivers to the context acceptor an
 internal name.  Since this name has been authenticated by a single
 mechanism, it contains only a single name (even if the internal name
 presented by the context initiator to gss_init_sec_context had
 multiple components).  Such names are termed internal mechanism
 names, or "MN"s and the names emitted by gss_accept_sec_context() are
 always of this type.  Since some applications may require MNs without
 wanting to incur the overhead of an authentication operation, a
 second function, gss_canonicalize_name(), is provided to convert a
 general internal name into an MN.
 Comparison of internal-form names may be accomplished via the
 gss_compare_name() routine, which returns true if the two names being
 compared refer to the same entity.  This removes the need for the
 application program to understand the syntaxes of the various
 printable names that a given GSS-API implementation may support.
 Since GSS-API assumes that all primitive names contained within a

Wray Standards Track [Page 16] RFC 2744 GSS-API V2: C-bindings January 2000

 given internal name refer to the same entity, gss_compare_name() can
 return true if the two names have at least one primitive name in
 common.  If the implementation embodies knowledge of equivalence
 relationships between names taken from different namespaces, this
 knowledge may also allow successful comparison of internal names
 containing no overlapping primitive elements.
 When used in large access control lists, the overhead of invoking
 gss_import_name() and gss_compare_name() on each name from the ACL
 may be prohibitive.  As an alternative way of supporting this case,
 GSS-API defines a special form of the contiguous string name which
 may be compared directly (e.g. with memcmp()).  Contiguous names
 suitable for comparison are generated by the gss_export_name()
 routine, which requires an MN as input.  Exported names may be re-
 imported by the gss_import_name() routine, and the resulting internal
 name will also be an MN.  The gss_OID constant GSS_C_NT_EXPORT_NAME
 indentifies the "export name" type, and the value of this constant is
 given in Appendix A.  Structurally, an exported name object consists
 of a header containing an OID identifying the mechanism that
 authenticated the name, and a trailer containing the name itself,
 where the syntax of the trailer is defined by the individual
 mechanism specification.   The precise format of an export name is
 defined in the language-independent GSS-API specification [GSSAPI].
 Note that the results obtained by using gss_compare_name() will in
 general be different from those obtained by invoking
 gss_canonicalize_name() and gss_export_name(), and then comparing the
 exported names.  The first series of operation determines whether two
 (unauthenticated) names identify the same principal; the second
 whether a particular mechanism would authenticate them as the same
 principal.  These two operations will in general give the same
 results only for MNs.
 The gss_name_t datatype should be implemented as a pointer type. To
 allow the compiler to aid the application programmer by performing
 type-checking, the use of (void *) is discouraged.  A pointer to an
 implementation-defined type is the preferred choice.
 Storage is allocated by routines that return gss_name_t values. A
 procedure, gss_release_name, is provided to free storage associated
 with an internal-form name.

Wray Standards Track [Page 17] RFC 2744 GSS-API V2: C-bindings January 2000

3.11. Channel Bindings

 GSS-API supports the use of user-specified tags to identify a given
 context to the peer application.  These tags are intended to be used
 to identify the particular communications channel that carries the
 context.  Channel bindings are communicated to the GSS-API using the
 following structure:
 typedef struct gss_channel_bindings_struct {
    OM_uint32       initiator_addrtype;
    gss_buffer_desc initiator_address;
    OM_uint32       acceptor_addrtype;
    gss_buffer_desc acceptor_address;
    gss_buffer_desc application_data;
 } *gss_channel_bindings_t;
 The initiator_addrtype and acceptor_addrtype fields denote the type
 of addresses contained in the initiator_address and acceptor_address
 buffers.  The address type should be one of the following:
 GSS_C_AF_UNSPEC     Unspecified address type
 GSS_C_AF_LOCAL      Host-local address type
 GSS_C_AF_INET       Internet address type (e.g. IP)
 GSS_C_AF_IMPLINK    ARPAnet IMP address type
 GSS_C_AF_PUP        pup protocols (eg BSP) address type
 GSS_C_AF_CHAOS      MIT CHAOS protocol address type
 GSS_C_AF_NS         XEROX NS address type
 GSS_C_AF_NBS        nbs address type
 GSS_C_AF_ECMA       ECMA address type
 GSS_C_AF_DATAKIT    datakit protocols address type
 GSS_C_AF_CCITT      CCITT protocols
 GSS_C_AF_SNA        IBM SNA address type
 GSS_C_AF_DECnet     DECnet address type
 GSS_C_AF_DLI        Direct data link interface address type
 GSS_C_AF_LAT        LAT address type
 GSS_C_AF_HYLINK     NSC Hyperchannel address type
 GSS_C_AF_APPLETALK  AppleTalk address type
 GSS_C_AF_BSC        BISYNC 2780/3780 address type
 GSS_C_AF_DSS        Distributed system services address type
 GSS_C_AF_OSI        OSI TP4 address type
 GSS_C_AF_X25        X.25
 GSS_C_AF_NULLADDR   No address specified
 Note that these symbols name address families rather than specific
 addressing formats.  For address families that contain several
 alternative address forms, the initiator_address and acceptor_address
 fields must contain sufficient information to determine which address

Wray Standards Track [Page 18] RFC 2744 GSS-API V2: C-bindings January 2000

 form is used.  When not otherwise specified, addresses should be
 specified in network byte-order (that is, native byte-ordering for
 the address family).
 Conceptually, the GSS-API concatenates the initiator_addrtype,
 initiator_address, acceptor_addrtype, acceptor_address and
 application_data to form an octet string.  The mechanism calculates a
 MIC over this octet string, and binds the MIC to the context
 establishment token emitted by gss_init_sec_context. The same
 bindings are presented by the context acceptor to
 gss_accept_sec_context, and a MIC is calculated in the same way. The
 calculated MIC is compared with that found in the token, and if the
 MICs differ, gss_accept_sec_context will return a GSS_S_BAD_BINDINGS
 error, and the context will not be established.  Some mechanisms may
 include the actual channel binding data in the token (rather than
 just a MIC); applications should therefore not use confidential data
 as channel-binding components.
 Individual mechanisms may impose additional constraints on addresses
 and address types that may appear in channel bindings.  For example,
 a mechanism may verify that the initiator_address field of the
 channel bindings presented to gss_init_sec_context contains the
 correct network address of the host system.  Portable applications
 should therefore ensure that they either provide correct information
 for the address fields, or omit addressing information, specifying
 GSS_C_AF_NULLADDR as the address-types.

3.12. Optional parameters

 Various parameters are described as optional.  This means that they
 follow a convention whereby a default value may be requested.  The
 following conventions are used for omitted parameters.  These
 conventions apply only to those parameters that are explicitly
 documented as optional.

3.12.1. gss_buffer_t types

 Specify GSS_C_NO_BUFFER as a value.  For an input parameter this
 signifies that default behavior is requested, while for an output
 parameter it indicates that the information that would be returned
 via the parameter is not required by the application.

3.12.2. Integer types (input)

 Individual parameter documentation lists values to be used to
 indicate default actions.

Wray Standards Track [Page 19] RFC 2744 GSS-API V2: C-bindings January 2000

3.12.3. Integer types (output)

 Specify NULL as the value for the pointer.

3.12.4. Pointer types

 Specify NULL as the value.

3.12.5. Object IDs

 Specify GSS_C_NO_OID as the value.

3.12.6. Object ID Sets

 Specify GSS_C_NO_OID_SET as the value.

3.12.7. Channel Bindings

 Specify GSS_C_NO_CHANNEL_BINDINGS to indicate that channel bindings
 are not to be used.

4. Additional Controls

 This section discusses the optional services that a context initiator
 may request of the GSS-API at context establishment. Each of these
 services is requested by setting a flag in the req_flags input
 parameter to gss_init_sec_context.
 The optional services currently defined are:
 Delegation - The (usually temporary) transfer of rights from
     initiator to acceptor, enabling the acceptor to authenticate
     itself as an agent of the initiator.
 Mutual Authentication - In addition to the initiator authenticating
     its identity to the context acceptor, the context acceptor should
     also authenticate itself to the initiator.
 Replay detection - In addition to providing message integrity
     services, gss_get_mic and gss_wrap should include message
     numbering information to enable gss_verify_mic and gss_unwrap to
     detect if a message has been duplicated.
 Out-of-sequence detection - In addition to providing message
     integrity services, gss_get_mic and gss_wrap should include
     message sequencing information to enable gss_verify_mic and
     gss_unwrap to detect if a message has been received out of
     sequence.

Wray Standards Track [Page 20] RFC 2744 GSS-API V2: C-bindings January 2000

 Anonymous authentication - The establishment of the security context
     should not reveal the initiator's identity to the context
     acceptor.
 Any currently undefined bits within such flag arguments should be
 ignored by GSS-API implementations when presented by an application,
 and should be set to zero when returned to the application by the
 GSS-API implementation.
 Some mechanisms may not support all optional services, and some
 mechanisms may only support some services in conjunction with others.
 Both gss_init_sec_context and gss_accept_sec_context inform the
 applications which services will be available from the context when
 the establishment phase is complete, via the ret_flags output
 parameter.  In general, if the security mechanism is capable of
 providing a requested service, it should do so, even if additional
 services must be enabled in order to provide the requested service.
 If the mechanism is incapable of providing a requested service, it
 should proceed without the service, leaving the application to abort
 the context establishment process if it considers the requested
 service to be mandatory.
 Some mechanisms may specify that support for some services is
 optional, and that implementors of the mechanism need not provide it.
 This is most commonly true of the confidentiality service, often
 because of legal restrictions on the use of data-encryption, but may
 apply to any of the services.  Such mechanisms are required to send
 at least one token from acceptor to initiator during context
 establishment when the initiator indicates a desire to use such a
 service, so that the initiating GSS-API can correctly indicate
 whether the service is supported by the acceptor's GSS-API.

4.1. Delegation

 The GSS-API allows delegation to be controlled by the initiating
 application via a boolean parameter to gss_init_sec_context(), the
 routine that establishes a security context.  Some mechanisms do not
 support delegation, and for such mechanisms attempts by an
 application to enable delegation are ignored.
 The acceptor of a security context for which the initiator enabled
 delegation will receive (via the delegated_cred_handle parameter of
 gss_accept_sec_context) a credential handle that contains the
 delegated identity, and this credential handle may be used to
 initiate subsequent GSS-API security contexts as an agent or delegate
 of the initiator.  If the original initiator's identity is "A" and
 the delegate's identity is "B", then, depending on the underlying
 mechanism, the identity embodied by the delegated credential may be

Wray Standards Track [Page 21] RFC 2744 GSS-API V2: C-bindings January 2000

 either "A" or "B acting for A".
 For many mechanisms that support delegation, a simple boolean does
 not provide enough control.  Examples of additional aspects of
 delegation control that a mechanism might provide to an application
 are duration of delegation, network addresses from which delegation
 is valid, and constraints on the tasks that may be performed by a
 delegate.  Such controls are presently outside the scope of the GSS-
 API.  GSS-API implementations supporting mechanisms offering
 additional controls should provide extension routines that allow
 these controls to be exercised (perhaps by modifying the initiator's
 GSS-API credential prior to its use in establishing a context).
 However, the simple delegation control provided by GSS-API should
 always be able to over-ride other mechanism-specific delegation
 controls - If the application instructs gss_init_sec_context() that
 delegation is not desired, then the implementation must not permit
 delegation to occur. This is an exception to the general rule that a
 mechanism may enable services even if they are not requested -
 delegation may only be provided at the explicit request of the
 application.

4.2. Mutual authentication

 Usually, a context acceptor will require that a context initiator
 authenticate itself so that the acceptor may make an access-control
 decision prior to performing a service for the initiator.  In some
 cases, the initiator may also request that the acceptor authenticate
 itself.  GSS-API allows the initiating application to request this
 mutual authentication service by setting a flag when calling
 gss_init_sec_context.
 The initiating application is informed as to whether or not the
 context acceptor has authenticated itself.  Note that some mechanisms
 may not support mutual authentication, and other mechanisms may
 always perform mutual authentication, whether or not the initiating
 application requests it.  In particular, mutual authentication my be
 required by some mechanisms in order to support replay or out-of-
 sequence message detection, and for such mechanisms a request for
 either of these services will automatically enable mutual
 authentication.

Wray Standards Track [Page 22] RFC 2744 GSS-API V2: C-bindings January 2000

4.3. Replay and out-of-sequence detection

 The GSS-API may provide detection of mis-ordered message once a
 security context has been established.  Protection may be applied to
 messages by either application, by calling either gss_get_mic or
 gss_wrap, and verified by the peer application by calling
 gss_verify_mic or gss_unwrap.
 gss_get_mic calculates a cryptographic MIC over an application
 message, and returns that MIC in a token.  The application should
 pass both the token and the message to the peer application, which
 presents them to gss_verify_mic.
 gss_wrap calculates a cryptographic MIC of an application message,
 and places both the MIC and the message inside a single token.  The
 Application should pass the token to the peer application, which
 presents it to gss_unwrap to extract the message and verify the MIC.
 Either pair of routines may be capable of detecting out-of-sequence
 message delivery, or duplication of messages. Details of such mis-
 ordered messages are indicated through supplementary status bits in
 the major status code returned by gss_verify_mic or gss_unwrap.  The
 relevant supplementary bits are:
 GSS_S_DUPLICATE_TOKEN - The token is a duplicate of one that has
                  already been received and processed.  Only
                  contexts that claim to provide replay detection
                  may set this bit.
 GSS_S_OLD_TOKEN - The token is too old to determine whether or
                  not it is a duplicate.  Contexts supporting
                  out-of-sequence detection but not replay
                  detection should always set this bit if
                  GSS_S_UNSEQ_TOKEN is set; contexts that support
                  replay detection should only set this bit if the
                  token is so old that it cannot be checked for
                  duplication.
 GSS_S_UNSEQ_TOKEN - A later token has already been processed.
 GSS_S_GAP_TOKEN - An earlier token has not yet been received.
 A mechanism need not maintain a list of all tokens that have been
 processed in order to support these status codes.  A typical
 mechanism might retain information about only the most recent "N"
 tokens processed, allowing it to distinguish duplicates and missing
 tokens within the most recent "N" messages; the receipt of a token
 older than the most recent "N" would result in a GSS_S_OLD_TOKEN
 status.

Wray Standards Track [Page 23] RFC 2744 GSS-API V2: C-bindings January 2000

4.4. Anonymous Authentication

 In certain situations, an application may wish to initiate the
 authentication process to authenticate a peer, without revealing its
 own identity.  As an example, consider an application providing
 access to a database containing medical information, and offering
 unrestricted access to the service.  A client of such a service might
 wish to authenticate the service (in order to establish trust in any
 information retrieved from it), but might not wish the service to be
 able to obtain the client's identity (perhaps due to privacy concerns
 about the specific inquiries, or perhaps simply to avoid being placed
 on mailing-lists).
 In normal use of the GSS-API, the initiator's identity is made
 available to the acceptor as a result of the context establishment
 process.  However, context initiators may request that their identity
 not be revealed to the context acceptor. Many mechanisms do not
 support anonymous authentication, and for such mechanisms the request
 will not be honored.  An authentication token will be still be
 generated, but the application is always informed if a requested
 service is unavailable, and has the option to abort context
 establishment if anonymity is valued above the other security
 services that would require a context to be established.
 In addition to informing the application that a context is
 established anonymously (via the ret_flags outputs from
 gss_init_sec_context and gss_accept_sec_context), the optional
 src_name output from gss_accept_sec_context and gss_inquire_context
 will, for such contexts, return a reserved internal-form name,
 defined by the implementation.
 When presented to gss_display_name, this reserved internal-form name
 will result in a printable name that is syntactically distinguishable
 from any valid principal name supported by the implementation,
 associated with a name-type object identifier with the value
 GSS_C_NT_ANONYMOUS, whose value us given in Appendix A.  The
 printable form of an anonymous name should be chosen such that it
 implies anonymity, since this name may appear in, for example, audit
 logs.  For example, the string "<anonymous>" might be a good choice,
 if no valid printable names supported by the implementation can begin
 with "<" and end with ">".

4.5. Confidentiality

 If a context supports the confidentiality service, gss_wrap may be
 used to encrypt application messages.  Messages are selectively
 encrypted, under the control of the conf_req_flag input parameter to
 gss_wrap.

Wray Standards Track [Page 24] RFC 2744 GSS-API V2: C-bindings January 2000

4.6. Inter-process context transfer

 GSS-API V2 provides routines (gss_export_sec_context and
 gss_import_sec_context) which allow a security context to be
 transferred between processes on a single machine.  The most common
 use for such a feature is a client-server design where the server is
 implemented as a single process that accepts incoming security
 contexts, which then launches child processes to deal with the data
 on these contexts.  In such a design, the child processes must have
 access to the security context data structure created within the
 parent by its call to gss_accept_sec_context so that they can use
 per-message protection services and delete the security context when
 the communication session ends.
 Since the security context data structure is expected to contain
 sequencing information, it is impractical in general to share a
 context between processes.  Thus GSS-API provides a call
 (gss_export_sec_context) that the process which currently owns the
 context can call to declare that it has no intention to use the
 context subsequently, and to create an inter-process token containing
 information needed by the adopting process to successfully import the
 context.  After successful completion of gss_export_sec_context, the
 original security context is made inaccessible to the calling process
 by GSS-API, and any context handles referring to this context are no
 longer valid.  The originating process transfers the inter-process
 token to the adopting process, which passes it to
 gss_import_sec_context, and a fresh gss_ctx_id_t is created such that
 it is functionally identical to the original context.
 The inter-process token may contain sensitive data from the original
 security context (including cryptographic keys). Applications using
 inter-process tokens to transfer security contexts must take
 appropriate steps to protect these tokens in transit.
 Implementations are not required to support the inter-process
 transfer of security contexts.  The ability to transfer a security
 context is indicated when the context is created, by
 gss_init_sec_context or gss_accept_sec_context setting the
 GSS_C_TRANS_FLAG bit in their ret_flags parameter.

4.7. The use of incomplete contexts

 Some mechanisms may allow the per-message services to be used before
 the context establishment process is complete.  For example, a
 mechanism may include sufficient information in its initial context-
 level token for the context acceptor to immediately decode messages
 protected with gss_wrap or gss_get_mic.  For such a mechanism, the
 initiating application need not wait until subsequent context-level

Wray Standards Track [Page 25] RFC 2744 GSS-API V2: C-bindings January 2000

 tokens have been sent and received before invoking the per-message
 protection services.
 The ability of a context to provide per-message services in advance
 of complete context establishment is indicated by the setting of the
 GSS_C_PROT_READY_FLAG bit in the ret_flags parameter from
 gss_init_sec_context and gss_accept_sec_context. Applications wishing
 to use per-message protection services on partially-established
 contexts should check this flag before attempting to invoke gss_wrap
 or gss_get_mic.

5. GSS-API Routine Descriptions

 In addition to the explicit major status codes documented here, the
 code GSS_S_FAILURE may be returned by any routine, indicating an
 implementation-specific or mechanism-specific error condition,
 further details of which are reported via the minor_status parameter.

5.1. gss_accept_sec_context

 OM_uint32 gss_accept_sec_context (
   OM_uint32           *minor_status,
   gss_ctx_id_t        *context_handle,
   const gss_cred_id_t acceptor_cred_handle,
   const gss_buffer_t  input_token_buffer,
   const gss_channel_bindings_t  input_chan_bindings,
   const gss_name_t    *src_name,
   gss_OID             *mech_type,
   gss_buffer_t        output_token,
   OM_uint32           *ret_flags,
   OM_uint32           *time_rec,
   gss_cred_id_t       *delegated_cred_handle)
 Purpose:
 Allows a remotely initiated security context between the application
 and a remote peer to be established.  The routine may return a
 output_token which should be transferred to the peer application,
 where the peer application will present it to gss_init_sec_context.
 If no token need be sent, gss_accept_sec_context will indicate this
 by setting the length field of the output_token argument to zero.  To
 complete the context establishment, one or more reply tokens may be
 required from the peer application; if so, gss_accept_sec_context
 will return a status flag of GSS_S_CONTINUE_NEEDED, in which case it
 should be called again when the reply token is received from the peer
 application, passing the token to gss_accept_sec_context via the
 input_token parameters.

Wray Standards Track [Page 26] RFC 2744 GSS-API V2: C-bindings January 2000

 Portable applications should be constructed to use the token length
 and return status to determine whether a token needs to be sent or
 waited for.  Thus a typical portable caller should always invoke
 gss_accept_sec_context within a loop:
 gss_ctx_id_t context_hdl = GSS_C_NO_CONTEXT;
 do {
   receive_token_from_peer(input_token);
   maj_stat = gss_accept_sec_context(&min_stat,
                                     &context_hdl,
                                     cred_hdl,
                                     input_token,
                                     input_bindings,
                                     &client_name,
                                     &mech_type,
                                     output_token,
                                     &ret_flags,
                                     &time_rec,
                                     &deleg_cred);
   if (GSS_ERROR(maj_stat)) {
     report_error(maj_stat, min_stat);
   };
   if (output_token->length != 0) {
     send_token_to_peer(output_token);
     gss_release_buffer(&min_stat, output_token);
   };
   if (GSS_ERROR(maj_stat)) {
     if (context_hdl != GSS_C_NO_CONTEXT)
       gss_delete_sec_context(&min_stat,
                              &context_hdl,
                              GSS_C_NO_BUFFER);
     break;
   };
 } while (maj_stat & GSS_S_CONTINUE_NEEDED);
 Whenever the routine returns a major status that includes the value
 GSS_S_CONTINUE_NEEDED, the context is not fully established and the
 following restrictions apply to the output parameters:
 The value returned via the time_rec parameter is undefined Unless the
 accompanying ret_flags parameter contains the bit
 GSS_C_PROT_READY_FLAG, indicating that per-message services may be
 applied in advance of a successful completion status, the value
 returned via the mech_type parameter may be undefined until the
 routine returns a major status value of GSS_S_COMPLETE.

Wray Standards Track [Page 27] RFC 2744 GSS-API V2: C-bindings January 2000

 The values of the GSS_C_DELEG_FLAG,
 GSS_C_MUTUAL_FLAG,GSS_C_REPLAY_FLAG, GSS_C_SEQUENCE_FLAG,
 GSS_C_CONF_FLAG,GSS_C_INTEG_FLAG and GSS_C_ANON_FLAG bits returned
 via the ret_flags parameter should contain the values that the
 implementation expects would be valid if context establishment were
 to succeed.
 The values of the GSS_C_PROT_READY_FLAG and GSS_C_TRANS_FLAG bits
 within ret_flags should indicate the actual state at the time
 gss_accept_sec_context returns, whether or not the context is fully
 established.
 Although this requires that GSS-API implementations set the
 GSS_C_PROT_READY_FLAG in the final ret_flags returned to a caller
 (i.e. when accompanied by a GSS_S_COMPLETE status code), applications
 should not rely on this behavior as the flag was not defined in
 Version 1 of the GSS-API. Instead, applications should be prepared to
 use per-message services after a successful context establishment,
 according to the GSS_C_INTEG_FLAG and GSS_C_CONF_FLAG values.
 All other bits within the ret_flags argument should be set to zero.
 While the routine returns GSS_S_CONTINUE_NEEDED, the values returned
 via the ret_flags argument indicate the services that the
 implementation expects to be available from the established context.
 If the initial call of gss_accept_sec_context() fails, the
 implementation should not create a context object, and should leave
 the value of the context_handle parameter set to GSS_C_NO_CONTEXT to
 indicate this.  In the event of a failure on a subsequent call, the
 implementation is permitted to delete the "half-built" security
 context (in which case it should set the context_handle parameter to
 GSS_C_NO_CONTEXT), but the preferred behavior is to leave the
 security context (and the context_handle parameter) untouched for the
 application to delete (using gss_delete_sec_context).
 During context establishment, the informational status bits
 GSS_S_OLD_TOKEN and GSS_S_DUPLICATE_TOKEN indicate fatal errors, and
 GSS-API mechanisms should always return them in association with a
 routine error of GSS_S_FAILURE.  This requirement for pairing did not
 exist in version 1 of the GSS-API specification, so applications that
 wish to run over version 1 implementations must special-case these
 codes.

Wray Standards Track [Page 28] RFC 2744 GSS-API V2: C-bindings January 2000

 Parameters:
 context_handle    gss_ctx_id_t, read/modify context handle for new
                      context.  Supply GSS_C_NO_CONTEXT for first
                      call; use value returned in subsequent calls.
                      Once gss_accept_sec_context() has returned a
                      value via this parameter, resources have been
                      assigned to the corresponding context, and must
                      be freed by the application after use with a
                      call to gss_delete_sec_context().
 acceptor_cred_handle  gss_cred_id_t, read Credential handle claimed
                       by context acceptor. Specify
                       GSS_C_NO_CREDENTIAL to accept the context as a
                       default principal.  If GSS_C_NO_CREDENTIAL is
                       specified, but no default acceptor principal is
                       defined, GSS_S_NO_CRED will be returned.
 input_token_buffer   buffer, opaque, read token obtained from remote
                      application.
 input_chan_bindings  channel bindings, read, optional Application-
                      specified bindings.  Allows application to
                      securely bind channel identification information
                      to the security context.  If channel bindings
                      are not used, specify GSS_C_NO_CHANNEL_BINDINGS.
 src_name             gss_name_t, modify, optional Authenticated name
                      of context initiator.  After use, this name
                      should be deallocated by passing it to
                      gss_release_name().  If not required, specify
                      NULL.
 mech_type            Object ID, modify, optional Security mechanism
                      used.  The returned OID value will be a pointer
                      into static storage, and should be treated as
                      read-only by the caller (in particular, it does
                      not need to be freed).  If not required, specify
                      NULL.
 output_token         buffer, opaque, modify Token to be passed to
                      peer application.  If the length field of the
                      returned token buffer is 0, then no token need
                      be passed to the peer application.  If a non-
                      zero length field is returned, the associated
                      storage must be freed after use by the
                      application with a call to gss_release_buffer().

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 ret_flags            bit-mask, modify, optional Contains various
                      independent flags, each of which indicates that
                      the context supports a specific service option.
                      If not needed, specify NULL.  Symbolic names are
                      provided for each flag, and the symbolic names
                      corresponding to the required flags should be
                      logically-ANDed with the ret_flags value to test
                      whether a given option is supported by the
                      context.  The flags are:
                      GSS_C_DELEG_FLAG
                      True - Delegated credentials are available
                             via the delegated_cred_handle
                             parameter
                      False - No credentials were delegated
                      GSS_C_MUTUAL_FLAG
                      True - Remote peer asked for mutual
                             authentication
                      False - Remote peer did not ask for mutual
                              authentication
                      GSS_C_REPLAY_FLAG
                      True - replay of protected messages
                             will be detected
                      False - replayed messages will not be
                              detected
                      GSS_C_SEQUENCE_FLAG
                      True - out-of-sequence protected
                             messages will be detected
                      False - out-of-sequence messages will not
                              be detected
                      GSS_C_CONF_FLAG
                      True - Confidentiality service may be
                             invoked by calling the gss_wrap
                             routine
                      False - No confidentiality service (via
                              gss_wrap) available. gss_wrap will
                              provide message encapsulation,
                              data-origin authentication and
                              integrity services only.
                      GSS_C_INTEG_FLAG
                      True - Integrity service may be invoked by
                             calling either gss_get_mic or
                             gss_wrap routines.
                      False - Per-message integrity service
                              unavailable.
                      GSS_C_ANON_FLAG
                      True - The initiator does not wish to
                             be authenticated; the src_name
                             parameter (if requested) contains

Wray Standards Track [Page 30] RFC 2744 GSS-API V2: C-bindings January 2000

                             an anonymous internal name.
                      False - The initiator has been
                              authenticated normally.
                      GSS_C_PROT_READY_FLAG
                      True - Protection services (as specified
                             by the states of the GSS_C_CONF_FLAG
                             and GSS_C_INTEG_FLAG) are available
                             if the accompanying major status
                             return value is either GSS_S_COMPLETE
                             or GSS_S_CONTINUE_NEEDED.
                      False - Protection services (as specified
                              by the states of the GSS_C_CONF_FLAG
                              and GSS_C_INTEG_FLAG) are available
                              only if the accompanying major status
                              return value is GSS_S_COMPLETE.
                      GSS_C_TRANS_FLAG
                      True - The resultant security context may
                             be transferred to other processes via
                             a call to gss_export_sec_context().
                      False - The security context is not
                              transferable.
                      All other bits should be set to zero.
 time_rec             Integer, modify, optional
                      number of seconds for which the context will
                      remain valid. Specify NULL if not required.
 delegated_cred_handle
                      gss_cred_id_t, modify, optional credential
                      handle for credentials received from context
                      initiator.  Only valid if deleg_flag in
                      ret_flags is true, in which case an explicit
                      credential handle (i.e. not GSS_C_NO_CREDENTIAL)
                      will be returned; if deleg_flag is false,
                      gss_accept_context() will set this parameter to
                      GSS_C_NO_CREDENTIAL.  If a credential handle is
                      returned, the associated resources must be
                      released by the application after use with a
                      call to gss_release_cred().  Specify NULL if not
                      required.
 minor_status         Integer, modify
                      Mechanism specific status code.
 GSS_S_CONTINUE_NEEDED Indicates that a token from the peer
                       application is required to complete the
                       context, and that gss_accept_sec_context must
                       be called again with that token.

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 GSS_S_DEFECTIVE_TOKEN Indicates that consistency checks performed on
                       the input_token failed.
 GSS_S_DEFECTIVE_CREDENTIAL Indicates that consistency checks
                       performed on the credential failed.
 GSS_S_NO_CRED     The supplied credentials were not valid for context
                       acceptance, or the credential handle did not
                       reference any credentials.
 GSS_S_CREDENTIALS_EXPIRED The referenced credentials have expired.
 GSS_S_BAD_BINDINGS  The input_token contains different channel
                       bindings to those specified via the
                       input_chan_bindings parameter.
 GSS_S_NO_CONTEXT  Indicates that the supplied context handle did not
                       refer to a valid context.
 GSS_S_BAD_SIG     The input_token contains an invalid MIC.
 GSS_S_OLD_TOKEN   The input_token was too old.  This is a fatal error
                       during context establishment.
 GSS_S_DUPLICATE_TOKEN The input_token is valid, but is a duplicate of
                       a token already processed.  This is a fatal
                       error during context establishment.
 GSS_S_BAD_MECH    The received token specified a mechanism that is
                       not supported by the implementation or the
                       provided credential.

5.2. gss_acquire_cred

 OM_uint32 gss_acquire_cred (
   OM_uint32         *minor_status,
   const gss_name_t  desired_name,
   OM_uint32         time_req,
   const gss_OID_set desired_mechs,
   gss_cred_usage_t  cred_usage,
   gss_cred_id_t     *output_cred_handle,
   gss_OID_set       *actual_mechs,
   OM_uint32         *time_rec)

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 Purpose:
 Allows an application to acquire a handle for a pre-existing
 credential by name.  GSS-API implementations must impose a local
 access-control policy on callers of this routine to prevent
 unauthorized callers from acquiring credentials to which they are not
 entitled.  This routine is not intended to provide a "login to the
 network" function, as such a function would involve the creation of
 new credentials rather than merely acquiring a handle to existing
 credentials.  Such functions, if required, should be defined in
 implementation-specific extensions to the API.
 If desired_name is GSS_C_NO_NAME, the call is interpreted as a
 request for a credential handle that will invoke default behavior
 when passed to gss_init_sec_context() (if cred_usage is
 GSS_C_INITIATE or GSS_C_BOTH) or gss_accept_sec_context() (if
 cred_usage is GSS_C_ACCEPT or GSS_C_BOTH).
 Mechanisms should honor the desired_mechs parameter, and return a
 credential that is suitable to use only with the requested
 mechanisms.  An exception to this is the case where one underlying
 credential element can be shared by multiple mechanisms; in this case
 it is permissible for an implementation to indicate all mechanisms
 with which the credential element may be used.  If desired_mechs is
 an empty set, behavior is undefined.
 This routine is expected to be used primarily by context acceptors,
 since implementations are likely to provide mechanism-specific ways
 of obtaining GSS-API initiator credentials from the system login
 process.  Some implementations may therefore not support the
 acquisition of GSS_C_INITIATE or GSS_C_BOTH credentials via
 gss_acquire_cred for any name other than GSS_C_NO_NAME, or a name
 produced by applying either gss_inquire_cred to a valid credential,
 or gss_inquire_context to an active context.
 If credential acquisition is time-consuming for a mechanism, the
 mechanism may choose to delay the actual acquisition until the
 credential is required (e.g. by gss_init_sec_context or
 gss_accept_sec_context).  Such mechanism-specific implementation
 decisions should be invisible to the calling application; thus a call
 of gss_inquire_cred immediately following the call of
 gss_acquire_cred must return valid credential data, and may therefore
 incur the overhead of a deferred credential acquisition.

Wray Standards Track [Page 33] RFC 2744 GSS-API V2: C-bindings January 2000

 Parameters:
 desired_name      gss_name_t, read
                   Name of principal whose credential
                   should be acquired
 time_req          Integer, read, optional
                   number of seconds that credentials
                   should remain valid. Specify GSS_C_INDEFINITE
                   to request that the credentials have the maximum
                   permitted lifetime.
 desired_mechs     Set of Object IDs, read, optional
                   set of underlying security mechanisms that
                   may be used.  GSS_C_NO_OID_SET may be used
                   to obtain an implementation-specific default.
 cred_usage        gss_cred_usage_t, read
                   GSS_C_BOTH - Credentials may be used
                      either to initiate or accept
                      security contexts.
                   GSS_C_INITIATE - Credentials will only be
                      used to initiate security contexts.
                   GSS_C_ACCEPT - Credentials will only be used to
                      accept security contexts.
 output_cred_handle  gss_cred_id_t, modify
                     The returned credential handle.  Resources
                     associated with this credential handle must
                     be released by the application after use
                     with a call to gss_release_cred().
 actual_mechs      Set of Object IDs, modify, optional
                   The set of mechanisms for which the
                   credential is valid.  Storage associated
                   with the returned OID-set must be released by
                   the application after use with a call to
                   gss_release_oid_set().  Specify NULL if not
                   required.
 time_rec          Integer, modify, optional
                   Actual number of seconds for which the
                   returned credentials will remain valid.  If the
                   implementation does not support expiration of
                   credentials, the value GSS_C_INDEFINITE will
                   be returned. Specify NULL if not required

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 minor_status      Integer, modify
                   Mechanism specific status code.
 Function value:  GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_BAD_MECH    Unavailable mechanism requested
 GSS_S_BAD_NAMETYPE Type contained within desired_name parameter
                    is not supported
 GSS_S_BAD_NAME    Value supplied for desired_name parameter is ill
                   formed.
 GSS_S_CREDENTIALS_EXPIRED The credentials could not be acquired
                           Because they have expired.
 GSS_S_NO_CRED     No credentials were found for the specified name.

5.3. gss_add_cred

 OM_uint32 gss_add_cred (
   OM_uint32           *minor_status,
   const gss_cred_id_t input_cred_handle,
   const gss_name_t    desired_name,
   const gss_OID       desired_mech,
   gss_cred_usage_t    cred_usage,
   OM_uint32           initiator_time_req,
   OM_uint32           acceptor_time_req,
   gss_cred_id_t       *output_cred_handle,
   gss_OID_set         *actual_mechs,
   OM_uint32           *initiator_time_rec,
   OM_uint32           *acceptor_time_rec)
 Purpose:
 Adds a credential-element to a credential.  The credential-element is
 identified by the name of the principal to which it refers.  GSS-API
 implementations must impose a local access-control policy on callers
 of this routine to prevent unauthorized callers from acquiring
 credential-elements to which they are not entitled. This routine is
 not intended to provide a "login to the network" function, as such a
 function would involve the creation of new mechanism-specific
 authentication data, rather than merely acquiring a GSS-API handle to
 existing data.  Such functions, if required, should be defined in
 implementation-specific extensions to the API.

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 If desired_name is GSS_C_NO_NAME, the call is interpreted as a
 request to add a credential element that will invoke default behavior
 when passed to gss_init_sec_context() (if cred_usage is
 GSS_C_INITIATE or GSS_C_BOTH) or gss_accept_sec_context() (if
 cred_usage is GSS_C_ACCEPT or GSS_C_BOTH).
 This routine is expected to be used primarily by context acceptors,
 since implementations are likely to provide mechanism-specific ways
 of obtaining GSS-API initiator credentials from the system login
 process.  Some implementations may therefore not support the
 acquisition of GSS_C_INITIATE or GSS_C_BOTH credentials via
 gss_acquire_cred for any name other than GSS_C_NO_NAME, or a name
 produced by applying either gss_inquire_cred to a valid credential,
 or gss_inquire_context to an active context.
 If credential acquisition is time-consuming for a mechanism, the
 mechanism may choose to delay the actual acquisition until the
 credential is required (e.g. by gss_init_sec_context or
 gss_accept_sec_context).  Such mechanism-specific implementation
 decisions should be invisible to the calling application; thus a call
 of gss_inquire_cred immediately following the call of gss_add_cred
 must return valid credential data, and may therefore incur the
 overhead of a deferred credential acquisition.
 This routine can be used to either compose a new credential
 containing all credential-elements of the original in addition to the
 newly-acquire credential-element, or to add the new credential-
 element to an existing credential. If NULL is specified for the
 output_cred_handle parameter argument, the new credential-element
 will be added to the credential identified by input_cred_handle; if a
 valid pointer is specified for the output_cred_handle parameter, a
 new credential handle will be created.
 If GSS_C_NO_CREDENTIAL is specified as the input_cred_handle,
 gss_add_cred will compose a credential (and set the
 output_cred_handle parameter accordingly) based on default behavior.
 That is, the call will have the same effect as if the application had
 first made a call to gss_acquire_cred(), specifying the same usage
 and passing GSS_C_NO_NAME as the desired_name parameter to obtain an
 explicit credential handle embodying default behavior, passed this
 credential handle to gss_add_cred(), and finally called
 gss_release_cred() on the first credential handle.
 If GSS_C_NO_CREDENTIAL is specified as the input_cred_handle
 parameter, a non-NULL output_cred_handle must be supplied.

Wray Standards Track [Page 36] RFC 2744 GSS-API V2: C-bindings January 2000

 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code.
 input_cred_handle gss_cred_id_t, read, optional
                   The credential to which a credential-element
                   will be added.  If GSS_C_NO_CREDENTIAL is
                   specified, the routine will compose the new
                   credential based on default behavior (see
                   description above).  Note that, while the
                   credential-handle is not modified by
                   gss_add_cred(), the underlying credential
                   will be modified if output_credential_handle
                   is NULL.
 desired_name      gss_name_t, read.
                   Name of principal whose credential
                   should be acquired.
 desired_mech      Object ID, read
                   Underlying security mechanism with which the
                   credential may be used.
 cred_usage        gss_cred_usage_t, read
                   GSS_C_BOTH - Credential may be used
                   either to initiate or accept
                   security contexts.
                   GSS_C_INITIATE - Credential will only be
                                    used to initiate security
                                    contexts.
                   GSS_C_ACCEPT - Credential will only be used to
                                  accept security contexts.
 initiator_time_req Integer, read, optional
                    number of seconds that the credential
                    should remain valid for initiating security
                    contexts.  This argument is ignored if the
                    composed credentials are of type GSS_C_ACCEPT.
                    Specify GSS_C_INDEFINITE to request that the
                    credentials have the maximum permitted
                    initiator lifetime.
 acceptor_time_req Integer, read, optional
                   number of seconds that the credential
                   should remain valid for accepting security
                   contexts.  This argument is ignored if the
                   composed credentials are of type GSS_C_INITIATE.

Wray Standards Track [Page 37] RFC 2744 GSS-API V2: C-bindings January 2000

                   Specify GSS_C_INDEFINITE to request that the
                   credentials have the maximum permitted initiator
                   lifetime.
 output_cred_handle gss_cred_id_t, modify, optional
                    The returned credential handle, containing
                    the new credential-element and all the
                    credential-elements from input_cred_handle.
                    If a valid pointer to a gss_cred_id_t is
                    supplied for this parameter, gss_add_cred
                    creates a new credential handle containing all
                    credential-elements from the input_cred_handle
                    and the newly acquired credential-element; if
                    NULL is specified for this parameter, the newly
                    acquired credential-element will be added
                    to the credential identified by input_cred_handle.
                    The resources associated with any credential
                    handle returned via this parameter must be
                    released by the application after use with a
                    call to gss_release_cred().
 actual_mechs      Set of Object IDs, modify, optional
                   The complete set of mechanisms for which
                   the new credential is valid.  Storage for
                   the returned OID-set must be freed by the
                   application after use with a call to
                   gss_release_oid_set(). Specify NULL if
                   not required.
 initiator_time_rec Integer, modify, optional
                    Actual number of seconds for which the
                    returned credentials will remain valid for
                    initiating contexts using the specified
                    mechanism.  If the implementation or mechanism
                    does not support expiration of credentials, the
                    value GSS_C_INDEFINITE will be returned. Specify
                    NULL if not required
 acceptor_time_rec Integer, modify, optional
                   Actual number of seconds for which the
                   returned credentials will remain valid for
                   accepting security contexts using the specified
                   mechanism.  If the implementation or mechanism
                   does not support expiration of credentials, the
                   value GSS_C_INDEFINITE will be returned. Specify
                   NULL if not required

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 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_BAD_MECH    Unavailable mechanism requested
 GSS_S_BAD_NAMETYPE Type contained within desired_name parameter
                   is not supported
 GSS_S_BAD_NAME    Value supplied for desired_name parameter is
                   ill-formed.
 GSS_S_DUPLICATE_ELEMENT The credential already contains an element
                   for the requested mechanism with overlapping
                   usage and validity period.
 GSS_S_CREDENTIALS_EXPIRED The required credentials could not be
                   added because they have expired.
 GSS_S_NO_CRED     No credentials were found for the specified name.

5.4. gss_add_oid_set_member

 OM_uint32 gss_add_oid_set_member (
   OM_uint32       *minor_status,
   const gss_OID   member_oid,
   gss_OID_set     *oid_set)
 Purpose:
 Add an Object Identifier to an Object Identifier set.  This routine
 is intended for use in conjunction with gss_create_empty_oid_set when
 constructing a set of mechanism OIDs for input to gss_acquire_cred.
 The oid_set parameter must refer to an OID-set that was created by
 GSS-API (e.g. a set returned by gss_create_empty_oid_set()). GSS-API
 creates a copy of the member_oid and inserts this copy into the set,
 expanding the storage allocated to the OID-set's elements array if
 necessary.  The routine may add the new member OID anywhere within
 the elements array, and implementations should verify that the new
 member_oid is not already contained within the elements array; if the
 member_oid is already present, the oid_set should remain unchanged.
 Parameters:
    minor_status      Integer, modify
                      Mechanism specific status code

Wray Standards Track [Page 39] RFC 2744 GSS-API V2: C-bindings January 2000

    member_oid        Object ID, read
                      The object identifier to copied into
                      the set.
    oid_set           Set of Object ID, modify
                      The set in which the object identifier
                      should be inserted.
 Function value:   GSS status code
    GSS_S_COMPLETE    Successful completion

5.5. gss_canonicalize_name

 OM_uint32 gss_canonicalize_name (
   OM_uint32        *minor_status,
   const gss_name_t input_name,
   const gss_OID    mech_type,
   gss_name_t       *output_name)
 Purpose:
 Generate a canonical mechanism name (MN) from an arbitrary internal
 name.  The mechanism name is the name that would be returned to a
 context acceptor on successful authentication of a context where the
 initiator used the input_name in a successful call to
 gss_acquire_cred, specifying an OID set containing <mech_type> as its
 only member, followed by a call to gss_init_sec_context, specifying
 <mech_type> as the authentication mechanism.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 input_name        gss_name_t, read
                   The name for which a canonical form is
                   desired
 mech_type         Object ID, read
                   The authentication mechanism for which the
                   canonical form of the name is desired.  The
                   desired mechanism must be specified explicitly;
                   no default is provided.

Wray Standards Track [Page 40] RFC 2744 GSS-API V2: C-bindings January 2000

 output_name       gss_name_t, modify
                   The resultant canonical name.  Storage
                   associated with this name must be freed by
                   the application after use with a call to
                   gss_release_name().
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion.
 GSS_S_BAD_MECH    The identified mechanism is not supported.
 GSS_S_BAD_NAMETYPE The provided internal name contains no elements
                   that could be processed by the specified
                   mechanism.
 GSS_S_BAD_NAME    The provided internal name was ill-formed.

5.6. gss_compare_name

 OM_uint32 gss_compare_name (
   OM_uint32        *minor_status,
   const gss_name_t name1,
   const gss_name_t name2,
   int              *name_equal)
 Purpose:
 Allows an application to compare two internal-form names to determine
 whether they refer to the same entity.
 If either name presented to gss_compare_name denotes an anonymous
 principal, the routines should indicate that the two names do not
 refer to the same identity.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code.
 name1             gss_name_t, read
                   internal-form name
 name2             gss_name_t, read
                   internal-form name

Wray Standards Track [Page 41] RFC 2744 GSS-API V2: C-bindings January 2000

 name_equal        boolean, modify
                   non-zero - names refer to same entity
                   zero - names refer to different entities
                         (strictly, the names are not known
                         to refer to the same identity).
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_BAD_NAMETYPE The two names were of incomparable types.
 GSS_S_BAD_NAME    One or both of name1 or name2 was ill-formed.

5.7. gss_context_time

 OM_uint32 gss_context_time (
   OM_uint32          *minor_status,
   const gss_ctx_id_t context_handle,
   OM_uint32          *time_rec)
 Purpose:
 Determines the number of seconds for which the specified context will
 remain valid.
 Parameters:
 minor_status      Integer, modify
                   Implementation specific status code.
 context_handle    gss_ctx_id_t, read
                   Identifies the context to be interrogated.
 time_rec          Integer, modify
                   Number of seconds that the context will remain
                   valid.  If the context has already expired,
                   zero will be returned.
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_CONTEXT_EXPIRED The context has already expired
 GSS_S_NO_CONTEXT  The context_handle parameter did not identify
                   a valid context

Wray Standards Track [Page 42] RFC 2744 GSS-API V2: C-bindings January 2000

5.8. gss_create_empty_oid_set

 OM_uint32 gss_create_empty_oid_set (
   OM_uint32    *minor_status,
   gss_OID_set  *oid_set)
 Purpose:
 Create an object-identifier set containing no object identifiers, to
 which members may be subsequently added using the
 gss_add_oid_set_member() routine.  These routines are intended to be
 used to construct sets of mechanism object identifiers, for input to
 gss_acquire_cred.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 oid_set           Set of Object IDs, modify
                   The empty object identifier set.
                   The routine will allocate the
                   gss_OID_set_desc object, which the
                   application must free after use with
                   a call to gss_release_oid_set().
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion

5.9. gss_delete_sec_context

 OM_uint32 gss_delete_sec_context (
   OM_uint32    *minor_status,
   gss_ctx_id_t *context_handle,
   gss_buffer_t output_token)
 Purpose:
 Delete a security context.  gss_delete_sec_context will delete the
 local data structures associated with the specified security context,
 and may generate an output_token, which when passed to the peer
 gss_process_context_token will instruct it to do likewise.  If no
 token is required by the mechanism, the GSS-API should set the length
 field of the output_token (if provided) to zero.  No further security
 services may be obtained using the context specified by
 context_handle.

Wray Standards Track [Page 43] RFC 2744 GSS-API V2: C-bindings January 2000

 In addition to deleting established security contexts,
 gss_delete_sec_context must also be able to delete "half-built"
 security contexts resulting from an incomplete sequence of
 gss_init_sec_context()/gss_accept_sec_context() calls.
 The output_token parameter is retained for compatibility with version
 1 of the GSS-API.  It is recommended that both peer applications
 invoke gss_delete_sec_context passing the value GSS_C_NO_BUFFER for
 the output_token parameter, indicating that no token is required, and
 that gss_delete_sec_context should simply delete local context data
 structures.  If the application does pass a valid buffer to
 gss_delete_sec_context, mechanisms are encouraged to return a zero-
 length token, indicating that no peer action is necessary, and that
 no token should be transferred by the application.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code.
 context_handle    gss_ctx_id_t, modify
                   context handle identifying context to delete.
                   After deleting the context, the GSS-API will set
                   this context handle to GSS_C_NO_CONTEXT.
 output_token      buffer, opaque, modify, optional
                   token to be sent to remote application to
                   instruct it to also delete the context.  It
                   is recommended that applications specify
                   GSS_C_NO_BUFFER for this parameter, requesting
                   local deletion only.  If a buffer parameter is
                   provided by the application, the mechanism may
                   return a token in it;  mechanisms that implement
                   only local deletion should set the length field of
                   this token to zero to indicate to the application
                   that no token is to be sent to the peer.
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_NO_CONTEXT  No valid context was supplied

Wray Standards Track [Page 44] RFC 2744 GSS-API V2: C-bindings January 2000

5.10.gss_display_name

 OM_uint32 gss_display_name (
   OM_uint32        *minor_status,
   const gss_name_t input_name,
   gss_buffer_t     output_name_buffer,
   gss_OID          *output_name_type)
 Purpose:
 Allows an application to obtain a textual representation of an opaque
 internal-form  name for display purposes.  The syntax of a printable
 name is defined by the GSS-API implementation.
 If input_name denotes an anonymous principal, the implementation
 should return the gss_OID value GSS_C_NT_ANONYMOUS as the
 output_name_type, and a textual name that is syntactically distinct
 from all valid supported printable names in output_name_buffer.
 If input_name was created by a call to gss_import_name, specifying
 GSS_C_NO_OID as the name-type, implementations that employ lazy
 conversion between name types may return GSS_C_NO_OID via the
 output_name_type parameter.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code.
 input_name        gss_name_t, read
                   name to be displayed
 output_name_buffer  buffer, character-string, modify
                   buffer to receive textual name string.
                   The application must free storage associated
                   with this name after use with a call to
                   gss_release_buffer().
 output_name_type  Object ID, modify, optional
                   The type of the returned name.  The returned
                   gss_OID will be a pointer into static storage,
                   and should be treated as read-only by the caller
                   (in particular, the application should not attempt
                   to free it). Specify NULL if not required.

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 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_BAD_NAME    input_name was ill-formed

5.11.gss_display_status

 OM_uint32 gss_display_status (
   OM_uint32      *minor_status,
   OM_uint32      status_value,
   int            status_type,
   const gss_OID  mech_type,
   OM_uint32      *message_context,
   gss_buffer_t   status_string)
 Purpose:
 Allows an application to obtain a textual representation of a GSS-API
 status code, for display to the user or for logging purposes.  Since
 some status values may indicate multiple conditions, applications may
 need to call gss_display_status multiple times, each call generating
 a single text string.  The message_context parameter is used by
 gss_display_status to store state information about which error
 messages have already been extracted from a given status_value;
 message_context must be initialized to 0 by the application prior to
 the first call, and gss_display_status will return a non-zero value
 in this parameter if there are further messages to extract.
 The message_context parameter contains all state information required
 by gss_display_status in order to extract further messages from the
 status_value;  even when a non-zero value is returned in this
 parameter, the application is not required to call gss_display_status
 again unless subsequent messages are desired.  The following code
 extracts all messages from a given status code and prints them to
 stderr:
 OM_uint32 message_context;
 OM_uint32 status_code;
 OM_uint32 maj_status;
 OM_uint32 min_status;
 gss_buffer_desc status_string;
        ...
 message_context = 0;
 do {

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   maj_status = gss_display_status (
                   &min_status,
                   status_code,
                   GSS_C_GSS_CODE,
                   GSS_C_NO_OID,
                   &message_context,
                   &status_string)
   fprintf(stderr,
           "%.*s\n",
          (int)status_string.length,
          (char *)status_string.value);
   gss_release_buffer(&min_status, &status_string);
 } while (message_context != 0);
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code.
 status_value      Integer, read
                   Status value to be converted
 status_type       Integer, read
                   GSS_C_GSS_CODE - status_value is a GSS status
                   code
 GSS_C_MECH_CODE - status_value is a mechanism
                   status code
 mech_type         Object ID, read, optional
                   Underlying mechanism (used to interpret a
                   minor status value) Supply GSS_C_NO_OID to
                   obtain the system default.
 message_context   Integer, read/modify
                   Should be initialized to zero by the
                   application prior to the first call.
                   On return from gss_display_status(),
                   a non-zero status_value parameter indicates
                   that additional messages may be extracted
                   from the status code via subsequent calls

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                   to gss_display_status(), passing the same
                   status_value, status_type, mech_type, and
                   message_context parameters.
 status_string     buffer, character string, modify
                   textual interpretation of the status_value.
                   Storage associated with this parameter must
                   be freed by the application after use with
                   a call to gss_release_buffer().
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_BAD_MECH    Indicates that translation in accordance with
                   an unsupported mechanism type was requested
 GSS_S_BAD_STATUS  The status value was not recognized, or the
                   status type was neither GSS_C_GSS_CODE nor
                   GSS_C_MECH_CODE.

5.12. gss_duplicate_name

 OM_uint32 gss_duplicate_name (
   OM_uint32        *minor_status,
   const gss_name_t src_name,
   gss_name_t       *dest_name)
 Purpose:
 Create an exact duplicate of the existing internal name src_name.
 The new dest_name will be independent of src_name (i.e. src_name and
 dest_name must both be released, and the release of one shall not
 affect the validity of the other).
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code.
 src_name          gss_name_t, read
                   internal name to be duplicated.
 dest_name         gss_name_t, modify
                   The resultant copy of <src_name>.
                   Storage associated with this name must
                   be freed by the application after use
                   with a call to gss_release_name().

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 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_BAD_NAME    The src_name parameter was ill-formed.

5.13. gss_export_name

 OM_uint32 gss_export_name (
   OM_uint32        *minor_status,
   const gss_name_t input_name,
   gss_buffer_t     exported_name)
 Purpose:
 To produce a canonical contiguous string representation of a
 mechanism name (MN), suitable for direct comparison (e.g. with
 memcmp) for use in authorization functions (e.g. matching entries in
 an access-control list).  The <input_name> parameter must specify a
 valid MN (i.e. an internal name generated by gss_accept_sec_context
 or by gss_canonicalize_name).
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 input_name        gss_name_t, read
                   The MN to be exported
 exported_name     gss_buffer_t, octet-string, modify
                   The canonical contiguous string form of
                   <input_name>.  Storage associated with
                   this string must freed by the application
                   after use with gss_release_buffer().
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_NAME_NOT_MN The provided internal name was not a mechanism
                   name.
 GSS_S_BAD_NAME    The provided internal name was ill-formed.
 GSS_S_BAD_NAMETYPE The internal name was of a type not supported
                   by the GSS-API implementation.

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5.14. gss_export_sec_context

 OM_uint32 gss_export_sec_context (
   OM_uint32    *minor_status,
   gss_ctx_id_t *context_handle,
   gss_buffer_t interprocess_token)
 Purpose:
 Provided to support the sharing of work between multiple processes.
 This routine will typically be used by the context-acceptor, in an
 application where a single process receives incoming connection
 requests and accepts security contexts over them, then passes the
 established context to one or more other processes for message
 exchange. gss_export_sec_context() deactivates the security context
 for the calling process and creates an interprocess token which, when
 passed to gss_import_sec_context in another process, will re-activate
 the context in the second process. Only a single instantiation of a
 given context may be active at any one time; a subsequent attempt by
 a context exporter to access the exported security context will fail.
 The implementation may constrain the set of processes by which the
 interprocess token may be imported, either as a function of local
 security policy, or as a result of implementation decisions.  For
 example, some implementations may constrain contexts to be passed
 only between processes that run under the same account, or which are
 part of the same process group.
 The interprocess token may contain security-sensitive information
 (for example cryptographic keys).  While mechanisms are encouraged to
 either avoid placing such sensitive information within interprocess
 tokens, or to encrypt the token before returning it to the
 application, in a typical object-library GSS-API implementation this
 may not be possible. Thus the application must take care to protect
 the interprocess token, and ensure that any process to which the
 token is transferred is trustworthy.
 If creation of the interprocess token is successful, the
 implementation shall deallocate all process-wide resources associated
 with the security context, and set the context_handle to
 GSS_C_NO_CONTEXT.  In the event of an error that makes it impossible
 to complete the export of the security context, the implementation
 must not return an interprocess token, and should strive to leave the
 security context referenced by the context_handle parameter
 untouched.  If this is impossible, it is permissible for the
 implementation to delete the security context, providing it also sets
 the context_handle parameter to GSS_C_NO_CONTEXT.

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 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 context_handle    gss_ctx_id_t, modify
                   context handle identifying the context to
                   transfer.
 interprocess_token   buffer, opaque, modify
                      token to be transferred to target process.
                      Storage associated with this token must be
                      freed by the application after use with a
                      call to gss_release_buffer().
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_CONTEXT_EXPIRED The context has expired
 GSS_S_NO_CONTEXT  The context was invalid
 GSS_S_UNAVAILABLE The operation is not supported.

5.15. gss_get_mic

 OM_uint32 gss_get_mic (
   OM_uint32          *minor_status,
   const gss_ctx_id_t context_handle,
   gss_qop_t             qop_req,
   const gss_buffer_t message_buffer,
   gss_buffer_t       msg_token)
 Purpose:
 Generates a cryptographic MIC for the supplied message, and places
 the MIC in a token for transfer to the peer application. The qop_req
 parameter allows a choice between several cryptographic algorithms,
 if supported by the chosen mechanism.
 Since some application-level protocols may wish to use tokens emitted
 by gss_wrap() to provide "secure framing", implementations must
 support derivation of MICs from zero-length messages.

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 Parameters:
 minor_status      Integer, modify
                   Implementation specific status code.
 context_handle    gss_ctx_id_t, read
                   identifies the context on which the message
                   will be sent
 qop_req           gss_qop_t, read, optional
                   Specifies requested quality of protection.
                   Callers are encouraged, on portability grounds,
                   to accept the default quality of protection
                   offered by the chosen mechanism, which may be
                   requested by specifying GSS_C_QOP_DEFAULT for
                   this parameter.  If an unsupported protection
                   strength is requested, gss_get_mic will return a
                   major_status of GSS_S_BAD_QOP.
 message_buffer    buffer, opaque, read
                   message to be protected
 msg_token         buffer, opaque, modify
                   buffer to receive token.  The application must
                   free storage associated with this buffer after
                   use with a call to gss_release_buffer().
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_CONTEXT_EXPIRED The context has already expired
 GSS_S_NO_CONTEXT  The context_handle parameter did not identify
                   a valid context
 GSS_S_BAD_QOP     The specified QOP is not supported by the
                   mechanism.

5.16. gss_import_name

 OM_uint32 gss_import_name (
   OM_uint32          *minor_status,
   const gss_buffer_t input_name_buffer,
   const gss_OID      input_name_type,
   gss_name_t         *output_name)

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 Purpose:
 Convert a contiguous string name to internal form.  In general, the
 internal name returned (via the <output_name> parameter) will not be
 an MN; the exception to this is if the <input_name_type> indicates
 that the contiguous string provided via the <input_name_buffer>
 parameter is of type GSS_C_NT_EXPORT_NAME, in which case the returned
 internal name will be an MN for the mechanism that exported the name.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 input_name_buffer  buffer, octet-string, read
                   buffer containing contiguous string name to convert
 input_name_type   Object ID, read, optional
                   Object ID specifying type of printable
                   name.  Applications may specify either
                   GSS_C_NO_OID to use a mechanism-specific
                   default printable syntax, or an OID recognized
                   by the GSS-API implementation to name a
                   specific namespace.
 output_name       gss_name_t, modify
                   returned name in internal form.  Storage
                   associated with this name must be freed
                   by the application after use with a call
                   to gss_release_name().
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_BAD_NAMETYPE The input_name_type was unrecognized
 GSS_S_BAD_NAME    The input_name parameter could not be interpreted
                   as a name of the specified type
 GSS_S_BAD_MECH    The input name-type was GSS_C_NT_EXPORT_NAME,
                   but the mechanism contained within the
                   input-name is not supported

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5.17. gss_import_sec_context

 OM_uint32 gss_import_sec_context (
   OM_uint32          *minor_status,
   const gss_buffer_t interprocess_token,
   gss_ctx_id_t       *context_handle)
 Purpose:
 Allows a process to import a security context established by another
 process.  A given interprocess token may be imported only once.  See
 gss_export_sec_context.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 interprocess_token  buffer, opaque, modify
                     token received from exporting process
 context_handle    gss_ctx_id_t, modify
                   context handle of newly reactivated context.
                   Resources associated with this context handle
                   must be released by the application after use
                   with a call to gss_delete_sec_context().
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion.
 GSS_S_NO_CONTEXT  The token did not contain a valid context
 reference.
 GSS_S_DEFECTIVE_TOKEN The token was invalid.
 GSS_S_UNAVAILABLE The operation is unavailable.
 GSS_S_UNAUTHORIZED Local policy prevents the import of this context
                    by the current process.

5.18. gss_indicate_mechs

 OM_uint32 gss_indicate_mechs (
   OM_uint32   *minor_status,
   gss_OID_set *mech_set)

Wray Standards Track [Page 54] RFC 2744 GSS-API V2: C-bindings January 2000

 Purpose:
 Allows an application to determine which underlying security
 mechanisms are available.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code.
 mech_set          set of Object IDs, modify
                   set of implementation-supported mechanisms.
                   The returned gss_OID_set value will be a
                   dynamically-allocated OID set, that should
                   be released by the caller after use with a
                   call to gss_release_oid_set().
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion

5.19. gss_init_sec_context

 OM_uint32 gss_init_sec_context (
   OM_uint32                    *minor_status,
   const gss_cred_id_t          initiator_cred_handle,
   gss_ctx_id_t                 *context_handle,\
   const gss_name_t             target_name,
   const gss_OID                mech_type,
   OM_uint32                    req_flags,
   OM_uint32                    time_req,
   const gss_channel_bindings_t input_chan_bindings,
   const gss_buffer_t           input_token
   gss_OID                      *actual_mech_type,
   gss_buffer_t                 output_token,
   OM_uint32                    *ret_flags,
   OM_uint32                    *time_rec )
 Purpose:
 Initiates the establishment of a security context between the
 application and a remote peer.  Initially, the input_token parameter
 should be specified either as GSS_C_NO_BUFFER, or as a pointer to a
 gss_buffer_desc object whose length field contains the value zero.
 The routine may return a output_token which should be transferred to
 the peer application, where the peer application will present it to
 gss_accept_sec_context.  If no token need be sent,
 gss_init_sec_context will indicate this by setting the length field

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 of the output_token argument to zero. To complete the context
 establishment, one or more reply tokens may be required from the peer
 application; if so, gss_init_sec_context will return a status
 containing the supplementary information bit GSS_S_CONTINUE_NEEDED.
 In this case, gss_init_sec_context should be called again when the
 reply token is received from the peer application, passing the reply
 token to gss_init_sec_context via the input_token parameters.
 Portable applications should be constructed to use the token length
 and return status to determine whether a token needs to be sent or
 waited for.  Thus a typical portable caller should always invoke
 gss_init_sec_context within a loop:
 int context_established = 0;
 gss_ctx_id_t context_hdl = GSS_C_NO_CONTEXT;
        ...
 input_token->length = 0;
 while (!context_established) {
   maj_stat = gss_init_sec_context(&min_stat,
                                   cred_hdl,
                                   &context_hdl,
                                   target_name,
                                   desired_mech,
                                   desired_services,
                                   desired_time,
                                   input_bindings,
                                   input_token,
                                   &actual_mech,
                                   output_token,
                                   &actual_services,
                                   &actual_time);
   if (GSS_ERROR(maj_stat)) {
     report_error(maj_stat, min_stat);
   };
   if (output_token->length != 0) {
     send_token_to_peer(output_token);
     gss_release_buffer(&min_stat, output_token)
   };
   if (GSS_ERROR(maj_stat)) {
     if (context_hdl != GSS_C_NO_CONTEXT)
       gss_delete_sec_context(&min_stat,
                              &context_hdl,
                              GSS_C_NO_BUFFER);
     break;
   };

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   if (maj_stat & GSS_S_CONTINUE_NEEDED) {
     receive_token_from_peer(input_token);
   } else {
     context_established = 1;
   };
 };
 Whenever the routine returns a major status that includes the value
 GSS_S_CONTINUE_NEEDED, the context is not fully established and the
 following restrictions apply to the output parameters:
    The value returned via the time_rec parameter is undefined Unless
    the accompanying ret_flags parameter contains the bit
    GSS_C_PROT_READY_FLAG, indicating that per-message services may be
    applied in advance of a successful completion status, the value
    returned via the actual_mech_type parameter is undefined until the
    routine returns a major status value of GSS_S_COMPLETE.
    The values of the GSS_C_DELEG_FLAG, GSS_C_MUTUAL_FLAG,
    GSS_C_REPLAY_FLAG, GSS_C_SEQUENCE_FLAG, GSS_C_CONF_FLAG,
    GSS_C_INTEG_FLAG and GSS_C_ANON_FLAG bits returned via the
    ret_flags parameter should contain the values that the
    implementation expects would be valid if context establishment
    were to succeed.  In particular, if the application has requested
    a service such as delegation or anonymous authentication via the
    req_flags argument, and such a service is unavailable from the
    underlying mechanism, gss_init_sec_context should generate a token
    that will not provide the service, and indicate via the ret_flags
    argument that the service will not be supported.  The application
    may choose to abort the context establishment by calling
    gss_delete_sec_context (if it cannot continue in the absence of
    the service), or it may choose to transmit the token and continue
    context establishment (if the service was merely desired but not
    mandatory).
    The values of the GSS_C_PROT_READY_FLAG and GSS_C_TRANS_FLAG bits
    within ret_flags should indicate the actual state at the time
    gss_init_sec_context returns, whether or not the context is fully
    established.
    GSS-API implementations that support per-message protection are
    encouraged to set the GSS_C_PROT_READY_FLAG in the final ret_flags
    returned to a caller (i.e. when accompanied by a GSS_S_COMPLETE
    status code).  However, applications should not rely on this
    behavior as the flag was not defined in Version 1 of the GSS-API.
    Instead, applications should determine what per-message services
    are available after a successful context establishment according
    to the GSS_C_INTEG_FLAG and GSS_C_CONF_FLAG values.

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    All other bits within the ret_flags argument should be set to
    zero.
 If the initial call of gss_init_sec_context() fails, the
 implementation should not create a context object, and should leave
 the value of the context_handle parameter set to GSS_C_NO_CONTEXT to
 indicate this.  In the event of a failure on a subsequent call, the
 implementation is permitted to delete the "half-built" security
 context (in which case it should set the context_handle parameter to
 GSS_C_NO_CONTEXT), but the preferred behavior is to leave the
 security context untouched for the application to delete (using
 gss_delete_sec_context).
 During context establishment, the informational status bits
 GSS_S_OLD_TOKEN and GSS_S_DUPLICATE_TOKEN indicate fatal errors, and
 GSS-API mechanisms should always return them in association with a
 routine error of GSS_S_FAILURE.  This requirement for pairing did not
 exist in version 1 of the GSS-API specification, so applications that
 wish to run over version 1 implementations must special-case these
 codes.
 Parameters:
 minor_status      Integer,  modify
                   Mechanism specific status code.
 initiator_cred_handle  gss_cred_id_t, read, optional
                        handle for credentials claimed.  Supply
                        GSS_C_NO_CREDENTIAL to act as a default
                        initiator principal.  If no default
                        initiator is defined, the function will
                        return GSS_S_NO_CRED.
 context_handle    gss_ctx_id_t, read/modify
                   context handle for new context.  Supply
                   GSS_C_NO_CONTEXT for first call; use value
                   returned by first call in continuation calls.
                   Resources associated with this context-handle
                   must be released by the application after use
                   with a call to gss_delete_sec_context().
 target_name       gss_name_t, read
                   Name of target
 mech_type         OID, read, optional
                   Object ID of desired mechanism. Supply
                   GSS_C_NO_OID to obtain an implementation
                   specific default

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 req_flags         bit-mask, read
                   Contains various independent flags, each of
                   which requests that the context support a
                   specific service option.  Symbolic
                   names are provided for each flag, and the
                   symbolic names corresponding to the required
                   flags should be logically-ORed
                   together to form the bit-mask value.  The
                   flags are:
                   GSS_C_DELEG_FLAG
                     True - Delegate credentials to remote peer
                     False - Don't delegate
                   GSS_C_MUTUAL_FLAG
                     True - Request that remote peer
                            authenticate itself
                     False - Authenticate self to remote peer
                             only
                   GSS_C_REPLAY_FLAG
                     True - Enable replay detection for
                            messages protected with gss_wrap
                            or gss_get_mic
                     False - Don't attempt to detect
                             replayed messages
                   GSS_C_SEQUENCE_FLAG
                     True - Enable detection of out-of-sequence
                            protected messages
                     False - Don't attempt to detect
                             out-of-sequence messages
                   GSS_C_CONF_FLAG
                     True - Request that confidentiality service
                            be made available (via gss_wrap)
                     False - No per-message confidentiality service
                             is required.
                   GSS_C_INTEG_FLAG
                     True - Request that integrity service be
                            made available (via gss_wrap or
                            gss_get_mic)
                     False - No per-message integrity service
                             is required.

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                   GSS_C_ANON_FLAG
                     True - Do not reveal the initiator's
                            identity to the acceptor.
                     False - Authenticate normally.
 time_req          Integer, read, optional
                   Desired number of seconds for which context
                   should remain valid.  Supply 0 to request a
                   default validity period.
 input_chan_bindings  channel bindings, read, optional
                      Application-specified bindings.  Allows
                      application to securely bind channel
                      identification information to the security
                      context.  Specify GSS_C_NO_CHANNEL_BINDINGS
                      if channel bindings are not used.
 input_token       buffer, opaque, read, optional (see text)
                   Token received from peer application.
                   Supply GSS_C_NO_BUFFER, or a pointer to
                   a buffer containing the value GSS_C_EMPTY_BUFFER
                   on initial call.
 actual_mech_type  OID, modify, optional
                   Actual mechanism used.  The OID returned via
                   this parameter will be a pointer to static
                   storage that should be treated as read-only;
                   In particular the application should not attempt
                   to free it.  Specify NULL if not required.
 output_token      buffer, opaque, modify
                   token to be sent to peer application.  If
                   the length field of the returned buffer is
                   zero, no token need be sent to the peer
                   application.  Storage associated with this
                   buffer must be freed by the application
                   after use with a call to gss_release_buffer().
 ret_flags         bit-mask, modify, optional
                   Contains various independent flags, each of which
                   indicates that the context supports a specific
                   service option.  Specify NULL if not
                   required.  Symbolic names are provided
                   for each flag, and the symbolic names
                   corresponding to the required flags should be
                   logically-ANDed with the ret_flags value to test
                   whether a given option is supported by the
                   context.  The flags are:

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                   GSS_C_DELEG_FLAG
                     True - Credentials were delegated to
                            the remote peer
                     False - No credentials were delegated
                   GSS_C_MUTUAL_FLAG
                     True - The remote peer has authenticated
                            itself.
                     False - Remote peer has not authenticated
                             itself.
                   GSS_C_REPLAY_FLAG
                     True - replay of protected messages
                            will be detected
                     False - replayed messages will not be
                             detected
                   GSS_C_SEQUENCE_FLAG
                     True - out-of-sequence protected
                            messages will be detected
                     False - out-of-sequence messages will
                             not be detected
                   GSS_C_CONF_FLAG
                     True - Confidentiality service may be
                            invoked by calling gss_wrap routine
                     False - No confidentiality service (via
                             gss_wrap) available. gss_wrap will
                             provide message encapsulation,
                             data-origin authentication and
                             integrity services only.
                   GSS_C_INTEG_FLAG
                     True - Integrity service may be invoked by
                            calling either gss_get_mic or gss_wrap
                            routines.
                     False - Per-message integrity service
                             unavailable.
                   GSS_C_ANON_FLAG
                     True - The initiator's identity has not been
                            revealed, and will not be revealed if
                            any emitted token is passed to the
                            acceptor.
                     False - The initiator's identity has been or
                             will be authenticated normally.
                   GSS_C_PROT_READY_FLAG

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                     True - Protection services (as specified
                            by the states of the GSS_C_CONF_FLAG
                            and GSS_C_INTEG_FLAG) are available for
                            use if the accompanying major status
                            return value is either GSS_S_COMPLETE or
                            GSS_S_CONTINUE_NEEDED.
                     False - Protection services (as specified
                             by the states of the GSS_C_CONF_FLAG
                             and GSS_C_INTEG_FLAG) are available
                             only if the accompanying major status
                             return value is GSS_S_COMPLETE.
                   GSS_C_TRANS_FLAG
                     True - The resultant security context may
                            be transferred to other processes via
                            a call to gss_export_sec_context().
                     False - The security context is not
                             transferable.
                   All other bits should be set to zero.
 time_rec          Integer, modify, optional
                   number of seconds for which the context
                   will remain valid. If the implementation does
                   not support context expiration, the value
                   GSS_C_INDEFINITE will be returned.  Specify
                   NULL if not required.
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_CONTINUE_NEEDED Indicates that a token from the peer
                       application is required to complete the
                       context, and that gss_init_sec_context
                       must be called again with that token.
 GSS_S_DEFECTIVE_TOKEN Indicates that consistency checks performed
                       on the input_token failed
 GSS_S_DEFECTIVE_CREDENTIAL Indicates that consistency checks
                            performed on the credential failed.
 GSS_S_NO_CRED     The supplied credentials were not valid for
                   context initiation, or the credential handle
                   did not reference any credentials.
 GSS_S_CREDENTIALS_EXPIRED The referenced credentials have expired

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 GSS_S_BAD_BINDINGS The input_token contains different channel
                    bindings to those specified via the
                    input_chan_bindings parameter
 GSS_S_BAD_SIG     The input_token contains an invalid MIC, or a MIC
                   that could not be verified
 GSS_S_OLD_TOKEN   The input_token was too old.  This is a fatal
                   error during context establishment
 GSS_S_DUPLICATE_TOKEN The input_token is valid, but is a duplicate
                       of a token already processed.  This is a
                       fatal error during context establishment.
 GSS_S_NO_CONTEXT  Indicates that the supplied context handle did
                   not refer to a valid context
 GSS_S_BAD_NAMETYPE The provided target_name parameter contained an
                    invalid or unsupported type of name
 GSS_S_BAD_NAME    The provided target_name parameter was ill-formed.
 GSS_S_BAD_MECH    The specified mechanism is not supported by the
                   provided credential, or is unrecognized by the
                   implementation.

5.20. gss_inquire_context

 OM_uint32 gss_inquire_context (
   OM_uint32          *minor_status,
   const gss_ctx_id_t context_handle,
   gss_name_t         *src_name,
   gss_name_t         *targ_name,
   OM_uint32          *lifetime_rec,
   gss_OID            *mech_type,
   OM_uint32          *ctx_flags,
   int                *locally_initiated,
   int                *open )
 Purpose:
 Obtains information about a security context.  The caller must
 already have obtained a handle that refers to the context, although
 the context need not be fully established.

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 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 context_handle    gss_ctx_id_t, read
                   A handle that refers to the security context.
 src_name          gss_name_t, modify, optional
                   The name of the context initiator.
                   If the context was established using anonymous
                   authentication, and if the application invoking
                   gss_inquire_context is the context acceptor,
                   an anonymous name will be returned.  Storage
                   associated with this name must be freed by the
                   application after use with a call to
                   gss_release_name().  Specify NULL if not
                   required.
 targ_name         gss_name_t, modify, optional
                   The name of the context acceptor.
                   Storage associated with this name must be
                   freed by the application after use with a call
                   to gss_release_name().  If the context acceptor
                   did not authenticate itself, and if the initiator
                   did not specify a target name in its call to
                   gss_init_sec_context(), the value GSS_C_NO_NAME
                   will be returned.  Specify NULL if not required.
 lifetime_rec      Integer, modify, optional
                   The number of seconds for which the context
                   will remain valid.  If the context has
                   expired, this parameter will be set to zero.
                   If the implementation does not support
                   context expiration, the value
                   GSS_C_INDEFINITE will be returned.  Specify
                   NULL if not required.
 mech_type         gss_OID, modify, optional
                   The security mechanism providing the
                   context.  The returned OID will be a
                   pointer to static storage that should
                   be treated as read-only by the application;
                   in particular the application should not
                   attempt to free it.  Specify NULL if not
                   required.

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 ctx_flags         bit-mask, modify, optional
                   Contains various independent flags, each of
                   which indicates that the context supports
                   (or is expected to support, if ctx_open is
                   false) a specific service option.  If not
                   needed, specify NULL.  Symbolic names are
                   provided for each flag, and the symbolic names
                   corresponding to the required flags
                   should be logically-ANDed with the ret_flags
                   value to test whether a given option is
                   supported by the context.  The flags are:
                   GSS_C_DELEG_FLAG
                     True - Credentials were delegated from
                            the initiator to the acceptor.
                     False - No credentials were delegated
                   GSS_C_MUTUAL_FLAG
                     True - The acceptor was authenticated
                            to the initiator
                     False - The acceptor did not authenticate
                             itself.
                   GSS_C_REPLAY_FLAG
                     True - replay of protected messages
                            will be detected
                     False - replayed messages will not be
                             detected
                   GSS_C_SEQUENCE_FLAG
                     True - out-of-sequence protected
                            messages will be detected
                     False - out-of-sequence messages will not
                             be detected
                   GSS_C_CONF_FLAG
                     True - Confidentiality service may be invoked
                            by calling gss_wrap routine
                     False - No confidentiality service (via
                             gss_wrap) available. gss_wrap will
                             provide message encapsulation,
                             data-origin authentication and
                             integrity services only.
                   GSS_C_INTEG_FLAG
                     True - Integrity service may be invoked by
                            calling either gss_get_mic or gss_wrap
                            routines.

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                     False - Per-message integrity service
                             unavailable.
                   GSS_C_ANON_FLAG
                     True - The initiator's identity will not
                            be revealed to the acceptor.
                            The src_name parameter (if
                            requested) contains an anonymous
                            internal name.
                     False - The initiator has been
                             authenticated normally.
                   GSS_C_PROT_READY_FLAG
                     True - Protection services (as specified
                            by the states of the GSS_C_CONF_FLAG
                            and GSS_C_INTEG_FLAG) are available
                            for use.
                     False - Protection services (as specified
                             by the states of the GSS_C_CONF_FLAG
                             and GSS_C_INTEG_FLAG) are available
                             only if the context is fully
                             established (i.e. if the open parameter
                             is non-zero).
                   GSS_C_TRANS_FLAG
                     True - The resultant security context may
                            be transferred to other processes via
                            a call to gss_export_sec_context().
                     False - The security context is not
                             transferable.
 locally_initiated Boolean, modify
                   Non-zero if the invoking application is the
                   context initiator.
                   Specify NULL if not required.
 open              Boolean, modify
                   Non-zero if the context is fully established;
                   Zero if a context-establishment token
                   is expected from the peer application.
                   Specify NULL if not required.
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_NO_CONTEXT  The referenced context could not be accessed.

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5.21. gss_inquire_cred

 OM_uint32 gss_inquire_cred (
   OM_uint32           *minor_status,
   const gss_cred_id_t cred_handle,
   gss_name_t          *name,
   OM_uint32           *lifetime,
   gss_cred_usage_t    *cred_usage,
   gss_OID_set         *mechanisms )
 Purpose:
 Obtains information about a credential.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 cred_handle       gss_cred_id_t, read
                   A handle that refers to the target credential.
                   Specify GSS_C_NO_CREDENTIAL to inquire about
                   the default initiator principal.
 name              gss_name_t, modify, optional
                   The name whose identity the credential asserts.
                   Storage associated with this name should be freed
                   by the application after use with a call to
                   gss_release_name().  Specify NULL if not required.
 lifetime          Integer, modify, optional
                   The number of seconds for which the credential
                   will remain valid.  If the credential has
                   expired, this parameter will be set to zero.
                   If the implementation does not support
                   credential expiration, the value
                   GSS_C_INDEFINITE will be returned.  Specify
                   NULL if not required.
 cred_usage        gss_cred_usage_t, modify, optional
                   How the credential may be used.  One of the
                   following:
                   GSS_C_INITIATE
                   GSS_C_ACCEPT
                   GSS_C_BOTH
                   Specify NULL if not required.

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 mechanisms        gss_OID_set, modify, optional
                   Set of mechanisms supported by the credential.
                   Storage associated with this OID set must be
                   freed by the application after use with a call
                   to gss_release_oid_set().  Specify NULL if not
                   required.
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_NO_CRED     The referenced credentials could not be accessed.
 GSS_S_DEFECTIVE_CREDENTIAL The referenced credentials were invalid.
 GSS_S_CREDENTIALS_EXPIRED The referenced credentials have expired.
                   If the lifetime parameter was not passed as NULL,
                   it will be set to 0.

5.22. gss_inquire_cred_by_mech

 OM_uint32 gss_inquire_cred_by_mech (
   OM_uint32           *minor_status,
   const gss_cred_id_t cred_handle,
   const gss_OID       mech_type,
   gss_name_t          *name,
   OM_uint32           *initiator_lifetime,
   OM_uint32           *acceptor_lifetime,
   gss_cred_usage_t    *cred_usage )
 Purpose:
 Obtains per-mechanism information about a credential.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 cred_handle       gss_cred_id_t, read
                   A handle that refers to the target credential.
                   Specify GSS_C_NO_CREDENTIAL to inquire about
                   the default initiator principal.
 mech_type         gss_OID, read
                   The mechanism for which information should be
                   returned.

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 name              gss_name_t, modify, optional
                   The name whose identity the credential asserts.
                   Storage associated with this name must be
                   freed by the application after use with a call
                   to gss_release_name().  Specify NULL if not
                   required.
 initiator_lifetime  Integer, modify, optional
                   The number of seconds for which the credential
                   will remain capable of initiating security contexts
                   under the specified mechanism.  If the credential
                   can no longer be used to initiate contexts, or if
                   the credential usage for this mechanism is
                   GSS_C_ACCEPT, this parameter will be set to zero.
                   If the implementation does not support expiration
                   of initiator credentials, the value
                   GSS_C_INDEFINITE will be returned.  Specify NULL
                   if not required.
 acceptor_lifetime Integer, modify, optional
                   The number of seconds for which the credential
                   will remain capable of accepting security contexts
                   under the specified mechanism.  If the credential
                   can no longer be used to accept contexts, or if
                   the credential usage for this mechanism is
                   GSS_C_INITIATE, this parameter will be set to zero.
                   If the implementation does not support expiration
                   of acceptor credentials, the value GSS_C_INDEFINITE
                   will be returned.  Specify NULL if not required.
 cred_usage        gss_cred_usage_t, modify, optional
                   How the credential may be used with the specified
                   mechanism.  One of the following:
                     GSS_C_INITIATE
                     GSS_C_ACCEPT
                     GSS_C_BOTH
                   Specify NULL if not required.
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_NO_CRED     The referenced credentials could not be accessed.
 GSS_S_DEFECTIVE_CREDENTIAL The referenced credentials were invalid.

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 GSS_S_CREDENTIALS_EXPIRED The referenced credentials have expired.
                  If the lifetime parameter was not passed as NULL,
                  it will be set to 0.

5.23. gss_inquire_mechs_for_name

 OM_uint32 gss_inquire_mechs_for_name (
   OM_uint32        *minor_status,
   const gss_name_t input_name,
   gss_OID_set      *mech_types )
 Purpose:
 Returns the set of mechanisms supported by the GSS-API implementation
 that may be able to process the specified name.
 Each mechanism returned will recognize at least one element within
 the name.  It is permissible for this routine to be implemented
 within a mechanism-independent GSS-API layer, using the type
 information contained within the presented name, and based on
 registration information provided by individual mechanism
 implementations.  This means that the returned mech_types set may
 indicate that a particular mechanism will understand the name when in
 fact it would refuse to accept the name as input to
 gss_canonicalize_name, gss_init_sec_context, gss_acquire_cred or
 gss_add_cred (due to some property of the specific name, as opposed
 to the name type).  Thus this routine should be used only as a pre-
 filter for a call to a subsequent mechanism-specific routine.
 Parameters:
 minor_status      Integer, modify
                   Implementation specific status code.
 input_name        gss_name_t, read
                   The name to which the inquiry relates.
 mech_types        gss_OID_set, modify
                   Set of mechanisms that may support the
                   specified name.  The returned OID set
                   must be freed by the caller after use
                   with a call to gss_release_oid_set().
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_BAD_NAME    The input_name parameter was ill-formed.

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 GSS_S_BAD_NAMETYPE The input_name parameter contained an invalid or
                    unsupported type of name

5.24. gss_inquire_names_for_mech

 OM_uint32 gss_inquire_names_for_mech (
   OM_uint32     *minor_status,
   const gss_OID mechanism,
   gss_OID_set   *name_types)
 Purpose:
 Returns the set of nametypes supported by the specified mechanism.
 Parameters:
 minor_status      Integer, modify
                   Implementation specific status code.
 mechanism         gss_OID, read
                   The mechanism to be interrogated.
 name_types        gss_OID_set, modify
                   Set of name-types supported by the specified
                   mechanism.  The returned OID set must be
                   freed by the application after use with a
                   call to gss_release_oid_set().
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion

5.25. gss_process_context_token

 OM_uint32 gss_process_context_token (
   OM_uint32          *minor_status,
   const gss_ctx_id_t context_handle,
   const gss_buffer_t token_buffer)
      Purpose:
 Provides a way to pass an asynchronous token to the security service.
 Most context-level tokens are emitted and processed synchronously by
 gss_init_sec_context and gss_accept_sec_context, and the application
 is informed as to whether further tokens are expected by the
 GSS_C_CONTINUE_NEEDED major status bit.  Occasionally, a mechanism
 may need to emit a context-level token at a point when the peer
 entity is not expecting a token.  For example, the initiator's final

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 call to gss_init_sec_context may emit a token and return a status of
 GSS_S_COMPLETE, but the acceptor's call to gss_accept_sec_context may
 fail.  The acceptor's mechanism may wish to send a token containing
 an error indication to the initiator, but the initiator is not
 expecting a token at this point, believing that the context is fully
 established.  Gss_process_context_token provides a way to pass such a
 token to the mechanism at any time.
 Parameters:
 minor_status      Integer, modify
                   Implementation specific status code.
 context_handle    gss_ctx_id_t, read
                   context handle of context on which token is to
                   be processed
 token_buffer      buffer, opaque, read
                   token to process
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_DEFECTIVE_TOKEN Indicates that consistency checks performed
                   on the token failed
 GSS_S_NO_CONTEXT  The context_handle did not refer to a valid context

5.26. gss_release_buffer

 OM_uint32 gss_release_buffer (
   OM_uint32    *minor_status,
   gss_buffer_t buffer)
 Purpose:
 Free storage associated with a buffer.  The storage must have been
 allocated by a GSS-API routine.  In addition to freeing the
 associated storage, the routine will zero the length field in the
 descriptor to which the buffer parameter refers, and implementations
 are encouraged to additionally set the pointer field in the
 descriptor to NULL.  Any buffer object returned by a GSS-API routine
 may be passed to gss_release_buffer (even if there is no storage
 associated with the buffer).

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 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 buffer            buffer, modify
                   The storage associated with the buffer will be
                   deleted.  The gss_buffer_desc object will not
                   be freed, but its length field will be zeroed.
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion

5.27. gss_release_cred

 OM_uint32 gss_release_cred (
   OM_uint32     *minor_status,
   gss_cred_id_t *cred_handle)
 Purpose:
 Informs GSS-API that the specified credential handle is no longer
 required by the application, and frees associated resources.
 Implementations are encouraged to set the cred_handle to
 GSS_C_NO_CREDENTIAL on successful completion of this call.
 Parameters:
 cred_handle       gss_cred_id_t, modify, optional
                   Opaque handle identifying credential
                   to be released.  If GSS_C_NO_CREDENTIAL
                   is supplied, the routine will complete
                   successfully, but will do nothing.
 minor_status      Integer, modify
                   Mechanism specific status code.
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_NO_CRED     Credentials could not be accessed.

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5.28. gss_release_name

 OM_uint32 gss_release_name (
   OM_uint32  *minor_status,
   gss_name_t *name)
 Purpose:
 Free GSSAPI-allocated storage associated with an internal-form name.
 Implementations are encouraged to set the name to GSS_C_NO_NAME on
 successful completion of this call.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 name              gss_name_t, modify
                   The name to be deleted
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_BAD_NAME    The name parameter did not contain a valid name

5.29. gss_release_oid_set

 OM_uint32 gss_release_oid_set (
   OM_uint32   *minor_status,
   gss_OID_set *set)
 Purpose:
 Free storage associated with a GSSAPI-generated gss_OID_set object.
 The set parameter must refer to an OID-set that was returned from a
 GSS-API routine.  gss_release_oid_set() will free the storage
 associated with each individual member OID, the OID set's elements
 array, and the gss_OID_set_desc.
 Implementations are encouraged to set the gss_OID_set parameter to
 GSS_C_NO_OID_SET on successful completion of this routine.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code

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 set               Set of Object IDs, modify
                   The storage associated with the gss_OID_set
                   will be deleted.
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion

5.30. gss_test_oid_set_member

 OM_uint32 gss_test_oid_set_member (
   OM_uint32         *minor_status,
   const gss_OID     member,
   const gss_OID_set set,
   int               *present)
 Purpose:
 Interrogate an Object Identifier set to determine whether a specified
 Object Identifier is a member.  This routine is intended to be used
 with OID sets returned by gss_indicate_mechs(), gss_acquire_cred(),
 and gss_inquire_cred(), but will also work with user-generated sets.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 member            Object ID, read
                   The object identifier whose presence
                   is to be tested.
 set               Set of Object ID, read
                   The Object Identifier set.
 present           Boolean, modify
                   non-zero if the specified OID is a member
                   of the set, zero if not.
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion

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5.31. gss_unwrap

 OM_uint32 gss_unwrap (
   OM_uint32          *minor_status,
   const gss_ctx_id_t context_handle,
   const gss_buffer_t input_message_buffer,
   gss_buffer_t       output_message_buffer,
   int                *conf_state,
   gss_qop_t          *qop_state)
 Purpose:
 Converts a message previously protected by gss_wrap back to a usable
 form, verifying the embedded MIC.  The conf_state parameter indicates
 whether the message was encrypted; the qop_state parameter indicates
 the strength of protection that was used to provide the
 confidentiality and integrity services.
 Since some application-level protocols may wish to use tokens emitted
 by gss_wrap() to provide "secure framing", implementations must
 support the wrapping and unwrapping of zero-length messages.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code.
 context_handle    gss_ctx_id_t, read
                   Identifies the context on which the message
                   arrived
 input_message_buffer  buffer, opaque, read
                   protected message
 output_message_buffer  buffer, opaque, modify
                   Buffer to receive unwrapped message.
                   Storage associated with this buffer must
                   be freed by the application after use use
                   with a call to gss_release_buffer().
 conf_state        boolean, modify, optional
                   Non-zero - Confidentiality and integrity
                              protection were used
                   Zero - Integrity service only was used
                   Specify NULL if not required

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 qop_state         gss_qop_t, modify, optional
                   Quality of protection provided.
                   Specify NULL if not required
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_DEFECTIVE_TOKEN The token failed consistency checks
 GSS_S_BAD_SIG     The MIC was incorrect
 GSS_S_DUPLICATE_TOKEN The token was valid, and contained a correct
                       MIC for the message, but it had already been
                       processed
 GSS_S_OLD_TOKEN   The token was valid, and contained a correct MIC
                   for the message, but it is too old to check for
                   duplication.
 GSS_S_UNSEQ_TOKEN The token was valid, and contained a correct MIC
                   for the message, but has been verified out of
                   sequence; a later token has already been
                   received.
 GSS_S_GAP_TOKEN   The token was valid, and contained a correct MIC
                   for the message, but has been verified out of
                   sequence; an earlier expected token has not yet
                   been received.
 GSS_S_CONTEXT_EXPIRED The context has already expired
 GSS_S_NO_CONTEXT  The context_handle parameter did not identify
                   a valid context

5.32. gss_verify_mic

 OM_uint32 gss_verify_mic (
   OM_uint32          *minor_status,
   const gss_ctx_id_t context_handle,
   const gss_buffer_t message_buffer,
   const gss_buffer_t token_buffer,
   gss_qop_t          *qop_state)

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 Purpose:
 Verifies that a cryptographic MIC, contained in the token parameter,
 fits the supplied message.  The qop_state parameter allows a message
 recipient to determine the strength of protection that was applied to
 the message.
 Since some application-level protocols may wish to use tokens emitted
 by gss_wrap() to provide "secure framing", implementations must
 support the calculation and verification of MICs over zero-length
 messages.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code.
 context_handle    gss_ctx_id_t, read
                   Identifies the context on which the message
                   arrived
 message_buffer    buffer, opaque, read
                   Message to be verified
 token_buffer      buffer, opaque, read
                   Token associated with message
 qop_state         gss_qop_t, modify, optional
                   quality of protection gained from MIC
                   Specify NULL if not required
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_DEFECTIVE_TOKEN The token failed consistency checks
 GSS_S_BAD_SIG     The MIC was incorrect
 GSS_S_DUPLICATE_TOKEN The token was valid, and contained a correct
                   MIC for the message, but it had already been
                   processed
 GSS_S_OLD_TOKEN   The token was valid, and contained a correct MIC
                   for the message, but it is too old to check for
                   duplication.

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 GSS_S_UNSEQ_TOKEN The token was valid, and contained a correct MIC
                   for the message, but has been verified out of
                   sequence; a later token has already been received.
 GSS_S_GAP_TOKEN   The token was valid, and contained a correct MIC
                   for the message, but has been verified out of
                   sequence; an earlier expected token has not yet
                   been received.
 GSS_S_CONTEXT_EXPIRED The context has already expired
 GSS_S_NO_CONTEXT  The context_handle parameter did not identify a
                   valid context

5.33. gss_wrap

 OM_uint32 gss_wrap (
   OM_uint32          *minor_status,
   const gss_ctx_id_t context_handle,
   int               conf_req_flag,
   gss_qop_t          qop_req
   const gss_buffer_t input_message_buffer,
   int                *conf_state,
   gss_buffer_t       output_message_buffer )
 Purpose:
 Attaches a cryptographic MIC and optionally encrypts the specified
 input_message.  The output_message contains both the MIC and the
 message.  The qop_req parameter allows a choice between several
 cryptographic algorithms, if supported by the chosen mechanism.
 Since some application-level protocols may wish to use tokens emitted
 by gss_wrap() to provide "secure framing", implementations must
 support the wrapping of zero-length messages.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code.
 context_handle    gss_ctx_id_t, read
                   Identifies the context on which the message
                   will be sent

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 conf_req_flag     boolean, read
                   Non-zero - Both confidentiality and integrity
                              services are requested
                   Zero - Only integrity service is requested
 qop_req           gss_qop_t, read, optional
                   Specifies required quality of protection.  A
                   mechanism-specific default may be requested by
                   setting qop_req to GSS_C_QOP_DEFAULT.  If an
                   unsupported protection strength is requested,
                   gss_wrap will return a major_status of
                   GSS_S_BAD_QOP.
 input_message_buffer  buffer, opaque, read
                   Message to be protected
 conf_state        boolean, modify, optional
                   Non-zero - Confidentiality, data origin
                              authentication and integrity
                              services have been applied
                   Zero - Integrity and data origin services only
                          has been applied.
                   Specify NULL if not required
 output_message_buffer  buffer, opaque, modify
                   Buffer to receive protected message.
                   Storage associated with this message must
                   be freed by the application after use with
                   a call to gss_release_buffer().
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_CONTEXT_EXPIRED The context has already expired
 GSS_S_NO_CONTEXT  The context_handle parameter did not identify a
                   valid context
 GSS_S_BAD_QOP     The specified QOP is not supported by the
                   mechanism.

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5.34. gss_wrap_size_limit

 OM_uint32 gss_wrap_size_limit (
   OM_uint32          *minor_status,
   const gss_ctx_id_t context_handle,
   int                conf_req_flag,
   gss_qop_t          qop_req,
   OM_uint32          req_output_size,
   OM_uint32          *max_input_size)
 Purpose:
 Allows an application to determine the maximum message size that, if
 presented to gss_wrap with the same conf_req_flag and qop_req
 parameters, will result in an output token containing no more than
 req_output_size bytes.
 This call is intended for use by applications that communicate over
 protocols that impose a maximum message size.  It enables the
 application to fragment messages prior to applying protection.
 GSS-API implementations are recommended but not required to detect
 invalid QOP values when gss_wrap_size_limit() is called. This routine
 guarantees only a maximum message size, not the availability of
 specific QOP values for message protection.
 Successful completion of this call does not guarantee that gss_wrap
 will be able to protect a message of length max_input_size bytes,
 since this ability may depend on the availability of system resources
 at the time that gss_wrap is called.  However, if the implementation
 itself imposes an upper limit on the length of messages that may be
 processed by gss_wrap, the implementation should not return a value
 via max_input_bytes that is greater than this length.
 Parameters:
 minor_status      Integer, modify
                   Mechanism specific status code
 context_handle    gss_ctx_id_t, read
                   A handle that refers to the security over
                   which the messages will be sent.
 conf_req_flag     Boolean, read
                   Indicates whether gss_wrap will be asked
                   to apply confidentiality protection in

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                   addition to integrity protection.  See
                   the routine description for gss_wrap
                   for more details.
 qop_req           gss_qop_t, read
                   Indicates the level of protection that
                   gss_wrap will be asked to provide.  See
                   the routine description for gss_wrap for
                   more details.
 req_output_size   Integer, read
                   The desired maximum size for tokens emitted
                   by gss_wrap.
 max_input_size    Integer, modify
                   The maximum input message size that may
                   be presented to gss_wrap in order to
                   guarantee that the emitted token shall
                   be no larger than req_output_size bytes.
 Function value:   GSS status code
 GSS_S_COMPLETE    Successful completion
 GSS_S_NO_CONTEXT  The referenced context could not be accessed.
 GSS_S_CONTEXT_EXPIRED The context has expired.
 GSS_S_BAD_QOP     The specified QOP is not supported by the
                   mechanism.

6. Security Considerations

 This document specifies a service interface for security facilities
 and services; as such, security considerations appear throughout the
 specification. Nonetheless, it is appropriate to summarize certain
 specific points relevant to GSS-API implementors and calling
 applications. Usage of the GSS-API interface does not in itself
 provide security services or assurance; instead, these attributes are
 dependent on the underlying mechanism(s) which support a GSS-API
 implementation. Callers must be attentive to the requests made to
 GSS-API calls and to the status indicators returned by GSS-API, as
 these specify the security service characteristics which GSS-API will
 provide. When the interprocess context transfer facility is used,
 appropriate local controls should be applied to constrain access to
 interprocess tokens and to the sensitive data which they contain.

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 Appendix A. GSS-API C header file gssapi.h
 C-language GSS-API implementations should include a copy of the
 following header-file.
 #ifndef GSSAPI_H_
 #define GSSAPI_H_
 /*
  * First, include stddef.h to get size_t defined.
  */
 #include <stddef.h>
 /*
  * If the platform supports the xom.h header file, it should be
  * included here.
  */
 #include <xom.h>
 /*
  * Now define the three implementation-dependent types.
  */
 typedef <platform-specific> gss_ctx_id_t;
 typedef <platform-specific> gss_cred_id_t;
 typedef <platform-specific> gss_name_t;
 /*
  * The following type must be defined as the smallest natural
  * unsigned integer supported by the platform that has at least
  * 32 bits of precision.
  */
 typedef <platform-specific> gss_uint32;
 #ifdef OM_STRING
 /*
  * We have included the xom.h header file.  Verify that OM_uint32
  * is defined correctly.
  */
 #if sizeof(gss_uint32) != sizeof(OM_uint32)
 #error Incompatible definition of OM_uint32 from xom.h
 #endif
 typedef OM_object_identifier gss_OID_desc, *gss_OID;

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 #else
 /*
  * We can't use X/Open definitions, so roll our own.
  */
 typedef gss_uint32 OM_uint32;
 typedef struct gss_OID_desc_struct {
   OM_uint32 length;
   void      *elements;
 } gss_OID_desc, *gss_OID;
 #endif
 typedef struct gss_OID_set_desc_struct  {
   size_t     count;
   gss_OID    elements;
 } gss_OID_set_desc, *gss_OID_set;
 typedef struct gss_buffer_desc_struct {
   size_t length;
   void *value;
 } gss_buffer_desc, *gss_buffer_t;
 typedef struct gss_channel_bindings_struct {
   OM_uint32 initiator_addrtype;
   gss_buffer_desc initiator_address;
   OM_uint32 acceptor_addrtype;
   gss_buffer_desc acceptor_address;
   gss_buffer_desc application_data;
 } *gss_channel_bindings_t;
 /*
  * For now, define a QOP-type as an OM_uint32
  */
 typedef OM_uint32 gss_qop_t;
 typedef int gss_cred_usage_t;
 /*
  * Flag bits for context-level services.
  */

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 #define GSS_C_DELEG_FLAG      1
 #define GSS_C_MUTUAL_FLAG     2
 #define GSS_C_REPLAY_FLAG     4
 #define GSS_C_SEQUENCE_FLAG   8
 #define GSS_C_CONF_FLAG       16
 #define GSS_C_INTEG_FLAG      32
 #define GSS_C_ANON_FLAG       64
 #define GSS_C_PROT_READY_FLAG 128
 #define GSS_C_TRANS_FLAG      256
 /*
  * Credential usage options
  */
 #define GSS_C_BOTH     0
 #define GSS_C_INITIATE 1
 #define GSS_C_ACCEPT   2
 /*
  * Status code types for gss_display_status
  */
 #define GSS_C_GSS_CODE  1
 #define GSS_C_MECH_CODE 2
 /*
  * The constant definitions for channel-bindings address families
  */
 #define GSS_C_AF_UNSPEC     0
 #define GSS_C_AF_LOCAL      1
 #define GSS_C_AF_INET       2
 #define GSS_C_AF_IMPLINK    3
 #define GSS_C_AF_PUP        4
 #define GSS_C_AF_CHAOS      5
 #define GSS_C_AF_NS         6
 #define GSS_C_AF_NBS        7
 #define GSS_C_AF_ECMA       8
 #define GSS_C_AF_DATAKIT    9
 #define GSS_C_AF_CCITT      10
 #define GSS_C_AF_SNA        11
 #define GSS_C_AF_DECnet     12
 #define GSS_C_AF_DLI        13
 #define GSS_C_AF_LAT        14
 #define GSS_C_AF_HYLINK     15
 #define GSS_C_AF_APPLETALK  16
 #define GSS_C_AF_BSC        17
 #define GSS_C_AF_DSS        18
 #define GSS_C_AF_OSI        19
 #define GSS_C_AF_X25        21

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 #define GSS_C_AF_NULLADDR   255
 /*
  * Various Null values
  */
 #define GSS_C_NO_NAME ((gss_name_t) 0)
 #define GSS_C_NO_BUFFER ((gss_buffer_t) 0)
 #define GSS_C_NO_OID ((gss_OID) 0)
 #define GSS_C_NO_OID_SET ((gss_OID_set) 0)
 #define GSS_C_NO_CONTEXT ((gss_ctx_id_t) 0)
 #define GSS_C_NO_CREDENTIAL ((gss_cred_id_t) 0)
 #define GSS_C_NO_CHANNEL_BINDINGS ((gss_channel_bindings_t) 0)
 #define GSS_C_EMPTY_BUFFER {0, NULL}
 /*
  * Some alternate names for a couple of the above
  * values.  These are defined for V1 compatibility.
  */
 #define GSS_C_NULL_OID GSS_C_NO_OID
 #define GSS_C_NULL_OID_SET GSS_C_NO_OID_SET
 /*
  * Define the default Quality of Protection for per-message
  * services.  Note that an implementation that offers multiple
  * levels of QOP may define GSS_C_QOP_DEFAULT to be either zero
  * (as done here) to mean "default protection", or to a specific
  * explicit QOP value.  However, a value of 0 should always be
  * interpreted by a GSS-API implementation as a request for the
  * default protection level.
  */
 #define GSS_C_QOP_DEFAULT 0
 /*
  * Expiration time of 2^32-1 seconds means infinite lifetime for a
  * credential or security context
  */
 #define GSS_C_INDEFINITE 0xfffffffful
 /*
  * The implementation must reserve static storage for a
  * gss_OID_desc object containing the value
  * {10, (void *)"\x2a\x86\x48\x86\xf7\x12"
  * "\x01\x02\x01\x01"},
  * corresponding to an object-identifier value of
  * {iso(1) member-body(2) United States(840) mit(113554)
  * infosys(1) gssapi(2) generic(1) user_name(1)}.  The constant
  * GSS_C_NT_USER_NAME should be initialized to point
  * to that gss_OID_desc.

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  • /

extern gss_OID GSS_C_NT_USER_NAME;

 /*
  * The implementation must reserve static storage for a
  * gss_OID_desc object containing the value
  * {10, (void *)"\x2a\x86\x48\x86\xf7\x12"
  *              "\x01\x02\x01\x02"},
  * corresponding to an object-identifier value of
  * {iso(1) member-body(2) United States(840) mit(113554)
  * infosys(1) gssapi(2) generic(1) machine_uid_name(2)}.
  * The constant GSS_C_NT_MACHINE_UID_NAME should be
  * initialized to point to that gss_OID_desc.
  */
 extern gss_OID GSS_C_NT_MACHINE_UID_NAME;
 /*
  * The implementation must reserve static storage for a
  * gss_OID_desc object containing the value
  * {10, (void *)"\x2a\x86\x48\x86\xf7\x12"
  *              "\x01\x02\x01\x03"},
  * corresponding to an object-identifier value of
  * {iso(1) member-body(2) United States(840) mit(113554)
  * infosys(1) gssapi(2) generic(1) string_uid_name(3)}.
  * The constant GSS_C_NT_STRING_UID_NAME should be
  * initialized to point to that gss_OID_desc.
  */
 extern gss_OID GSS_C_NT_STRING_UID_NAME;
 /*
  * The implementation must reserve static storage for a
  * gss_OID_desc object containing the value
  * {6, (void *)"\x2b\x06\x01\x05\x06\x02"},
  * corresponding to an object-identifier value of
  * {iso(1) org(3) dod(6) internet(1) security(5)
  * nametypes(6) gss-host-based-services(2)).  The constant
  * GSS_C_NT_HOSTBASED_SERVICE_X should be initialized to point
  * to that gss_OID_desc.  This is a deprecated OID value, and
  * implementations wishing to support hostbased-service names
  * should instead use the GSS_C_NT_HOSTBASED_SERVICE OID,
  * defined below, to identify such names;
  * GSS_C_NT_HOSTBASED_SERVICE_X should be accepted a synonym
  * for GSS_C_NT_HOSTBASED_SERVICE when presented as an input
  * parameter, but should not be emitted by GSS-API
  * implementations
  */
 extern gss_OID GSS_C_NT_HOSTBASED_SERVICE_X;

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 /*
  * The implementation must reserve static storage for a
  * gss_OID_desc object containing the value
  * {10, (void *)"\x2a\x86\x48\x86\xf7\x12"
  *              "\x01\x02\x01\x04"}, corresponding to an
  * object-identifier value of {iso(1) member-body(2)
  * Unites States(840) mit(113554) infosys(1) gssapi(2)
  * generic(1) service_name(4)}.  The constant
  * GSS_C_NT_HOSTBASED_SERVICE should be initialized
  * to point to that gss_OID_desc.
  */
 extern gss_OID GSS_C_NT_HOSTBASED_SERVICE;
 /*
  * The implementation must reserve static storage for a
  * gss_OID_desc object containing the value
  * {6, (void *)"\x2b\x06\01\x05\x06\x03"},
  * corresponding to an object identifier value of
  * {1(iso), 3(org), 6(dod), 1(internet), 5(security),
  * 6(nametypes), 3(gss-anonymous-name)}.  The constant
  * and GSS_C_NT_ANONYMOUS should be initialized to point
  * to that gss_OID_desc.
  */
 extern gss_OID GSS_C_NT_ANONYMOUS;
 /*
  * The implementation must reserve static storage for a
  * gss_OID_desc object containing the value
  * {6, (void *)"\x2b\x06\x01\x05\x06\x04"},
  * corresponding to an object-identifier value of
  * {1(iso), 3(org), 6(dod), 1(internet), 5(security),
  * 6(nametypes), 4(gss-api-exported-name)}.  The constant
  * GSS_C_NT_EXPORT_NAME should be initialized to point
  * to that gss_OID_desc.
  */
 extern gss_OID GSS_C_NT_EXPORT_NAME;
 /* Major status codes */
 #define GSS_S_COMPLETE 0
 /*
  * Some "helper" definitions to make the status code macros obvious.
  */
 #define GSS_C_CALLING_ERROR_OFFSET 24
 #define GSS_C_ROUTINE_ERROR_OFFSET 16

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 #define GSS_C_SUPPLEMENTARY_OFFSET 0
 #define GSS_C_CALLING_ERROR_MASK 0377ul
 #define GSS_C_ROUTINE_ERROR_MASK 0377ul
 #define GSS_C_SUPPLEMENTARY_MASK 0177777ul
 /*
  * The macros that test status codes for error conditions.
  * Note that the GSS_ERROR() macro has changed slightly from
  * the V1 GSS-API so that it now evaluates its argument
  * only once.
  */
 #define GSS_CALLING_ERROR(x) \
  (x & (GSS_C_CALLING_ERROR_MASK << GSS_C_CALLING_ERROR_OFFSET))
 #define GSS_ROUTINE_ERROR(x) \
  (x & (GSS_C_ROUTINE_ERROR_MASK << GSS_C_ROUTINE_ERROR_OFFSET))
 #define GSS_SUPPLEMENTARY_INFO(x) \
  (x & (GSS_C_SUPPLEMENTARY_MASK << GSS_C_SUPPLEMENTARY_OFFSET))
 #define GSS_ERROR(x) \
  (x & ((GSS_C_CALLING_ERROR_MASK << GSS_C_CALLING_ERROR_OFFSET) | \
        (GSS_C_ROUTINE_ERROR_MASK << GSS_C_ROUTINE_ERROR_OFFSET)))
 /*
  * Now the actual status code definitions
  */
 /*
  * Calling errors:
  • /

#define GSS_S_CALL_INACCESSIBLE_READ \

 (1ul << GSS_C_CALLING_ERROR_OFFSET)
 #define GSS_S_CALL_INACCESSIBLE_WRITE \
 (2ul << GSS_C_CALLING_ERROR_OFFSET)
 #define GSS_S_CALL_BAD_STRUCTURE \
 (3ul << GSS_C_CALLING_ERROR_OFFSET)
 /*
  * Routine errors:
  */
 #define GSS_S_BAD_MECH             (1ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_BAD_NAME             (2ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_BAD_NAMETYPE         (3ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_BAD_BINDINGS         (4ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_BAD_STATUS           (5ul <<

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 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_BAD_SIG              (6ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_BAD_MIC GSS_S_BAD_SIG
 #define GSS_S_NO_CRED              (7ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_NO_CONTEXT           (8ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_DEFECTIVE_TOKEN      (9ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_DEFECTIVE_CREDENTIAL (10ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_CREDENTIALS_EXPIRED  (11ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_CONTEXT_EXPIRED      (12ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_FAILURE              (13ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_BAD_QOP              (14ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_UNAUTHORIZED         (15ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_UNAVAILABLE          (16ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_DUPLICATE_ELEMENT    (17ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 #define GSS_S_NAME_NOT_MN          (18ul <<
 GSS_C_ROUTINE_ERROR_OFFSET)
 /*
  * Supplementary info bits:
  */
 #define GSS_S_CONTINUE_NEEDED \
          (1ul << (GSS_C_SUPPLEMENTARY_OFFSET + 0))
 #define GSS_S_DUPLICATE_TOKEN \
          (1ul << (GSS_C_SUPPLEMENTARY_OFFSET + 1))
 #define GSS_S_OLD_TOKEN \
          (1ul << (GSS_C_SUPPLEMENTARY_OFFSET + 2))
 #define GSS_S_UNSEQ_TOKEN \
          (1ul << (GSS_C_SUPPLEMENTARY_OFFSET + 3))
 #define GSS_S_GAP_TOKEN \
          (1ul << (GSS_C_SUPPLEMENTARY_OFFSET + 4))
 /*
  * Finally, function prototypes for the GSS-API routines.
  */

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 OM_uint32 gss_acquire_cred
               (OM_uint32 ,             /*  minor_status */
                const gss_name_t,       /* desired_name */
                OM_uint32,              /* time_req */
                const gss_OID_set,      /* desired_mechs */
                gss_cred_usage_t,       /* cred_usage */
                gss_cred_id_t ,         /* output_cred_handle */
                gss_OID_set ,           /* actual_mechs */
                OM_uint32 *             /* time_rec */
               );
 OM_uint32 gss_release_cred
               (OM_uint32 ,             /* minor_status */
                gss_cred_id_t *         /* cred_handle */
               );
 OM_uint32 gss_init_sec_context
               (OM_uint32 ,             /* minor_status */
                const gss_cred_id_t,    /* initiator_cred_handle */
                gss_ctx_id_t ,          /* context_handle */
                const gss_name_t,       /* target_name */
                const gss_OID,          /* mech_type */
                OM_uint32,              /* req_flags */
                OM_uint32,              /* time_req */
                const gss_channel_bindings_t,
                                        /* input_chan_bindings */
                const gss_buffer_t,     /* input_token */
                gss_OID ,               /* actual_mech_type */
                gss_buffer_t,           /* output_token */
                OM_uint32 ,             /* ret_flags */
                OM_uint32 *             /* time_rec */
               );
 OM_uint32 gss_accept_sec_context
               (OM_uint32 ,             /* minor_status */
                gss_ctx_id_t ,          /* context_handle */
                const gss_cred_id_t,    /* acceptor_cred_handle */
                const gss_buffer_t,     /* input_token_buffer */
                const gss_channel_bindings_t,
                                        /* input_chan_bindings */
                gss_name_t ,            /* src_name */
                gss_OID ,               /* mech_type */
                gss_buffer_t,           /* output_token */
                OM_uint32 ,             /* ret_flags */
                OM_uint32 ,             /* time_rec */
                gss_cred_id_t *         /* delegated_cred_handle */
               );

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 OM_uint32 gss_process_context_token
               (OM_uint32 ,             /* minor_status */
                const gss_ctx_id_t,     /* context_handle */
                const gss_buffer_t      /* token_buffer */
               );
 OM_uint32 gss_delete_sec_context
               (OM_uint32 ,             /* minor_status */
                gss_ctx_id_t ,          /* context_handle */
                gss_buffer_t            /* output_token */
               );
 OM_uint32 gss_context_time
               (OM_uint32 ,             /* minor_status */
                const gss_ctx_id_t,     /* context_handle */
                OM_uint32 *             /* time_rec */
               );
 OM_uint32 gss_get_mic
               (OM_uint32 ,             /* minor_status */
                const gss_ctx_id_t,     /* context_handle */
                gss_qop_t,              /* qop_req */
                const gss_buffer_t,     /* message_buffer */
                gss_buffer_t            /* message_token */
               );
 OM_uint32 gss_verify_mic
               (OM_uint32 ,             /* minor_status */
                const gss_ctx_id_t,     /* context_handle */
                const gss_buffer_t,     /* message_buffer */
                const gss_buffer_t,     /* token_buffer */
                gss_qop_t *             /* qop_state */
               );
 OM_uint32 gss_wrap
               (OM_uint32 ,             /* minor_status */
                const gss_ctx_id_t,     /* context_handle */
                int,                    /* conf_req_flag */
                gss_qop_t,              /* qop_req */
                const gss_buffer_t,     /* input_message_buffer */
                int ,                   /* conf_state */
                gss_buffer_t            /* output_message_buffer */
               );

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 OM_uint32 gss_unwrap
               (OM_uint32 ,             /* minor_status */
                const gss_ctx_id_t,     /* context_handle */
                const gss_buffer_t,     /* input_message_buffer */
                gss_buffer_t,           /* output_message_buffer */
                int ,                   /* conf_state */
                gss_qop_t *             /* qop_state */
               );
 OM_uint32 gss_display_status
               (OM_uint32 ,             /* minor_status */
                OM_uint32,              /* status_value */
                int,                    /* status_type */
                const gss_OID,          /* mech_type */
                OM_uint32 ,             /* message_context */
                gss_buffer_t            /* status_string */
               );
 OM_uint32 gss_indicate_mechs
               (OM_uint32 ,             /* minor_status */
                gss_OID_set *           /* mech_set */
               );
 OM_uint32 gss_compare_name
               (OM_uint32 ,             /* minor_status */
                const gss_name_t,       /* name1 */
                const gss_name_t,       /* name2 */
                int *                   /* name_equal */
               );
 OM_uint32 gss_display_name
               (OM_uint32 ,             /* minor_status */
                const gss_name_t,       /* input_name */
                gss_buffer_t,           /* output_name_buffer */
                gss_OID *               /* output_name_type */
               );
 OM_uint32 gss_import_name
               (OM_uint32 ,             /* minor_status */
                const gss_buffer_t,     /* input_name_buffer */
                const gss_OID,          /* input_name_type */
                gss_name_t *            /* output_name */
               );

Wray Standards Track [Page 93] RFC 2744 GSS-API V2: C-bindings January 2000

 OM_uint32 gss_export_name
               (OM_uint32,              /* minor_status */
                const gss_name_t,       /* input_name */
                gss_buffer_t            /* exported_name */
               );
 OM_uint32 gss_release_name
               (OM_uint32 *,            /* minor_status */
                gss_name_t *            /* input_name */
               );
 OM_uint32 gss_release_buffer
               (OM_uint32 ,             /* minor_status */
                gss_buffer_t            /* buffer */
               );
 OM_uint32 gss_release_oid_set
               (OM_uint32 ,             /* minor_status */
                gss_OID_set *           /* set */
               );
 OM_uint32 gss_inquire_cred
               (OM_uint32 ,             /* minor_status */
                const gss_cred_id_t,    /* cred_handle */
                gss_name_t ,            /* name */
                OM_uint32 ,             /* lifetime */
                gss_cred_usage_t ,      /* cred_usage */
                gss_OID_set *           /* mechanisms */
               );
 OM_uint32 gss_inquire_context (
                OM_uint32 ,             /* minor_status */
                const gss_ctx_id_t,     /* context_handle */
                gss_name_t ,            /* src_name */
                gss_name_t ,            /* targ_name */
                OM_uint32 ,             /* lifetime_rec */
                gss_OID ,               /* mech_type */
                OM_uint32 ,             /* ctx_flags */
                int ,                   /* locally_initiated */
                int *                   /* open */
               );

Wray Standards Track [Page 94] RFC 2744 GSS-API V2: C-bindings January 2000

 OM_uint32 gss_wrap_size_limit (
                OM_uint32 ,             /* minor_status */
                const gss_ctx_id_t,     /* context_handle */
                int,                    /* conf_req_flag */
                gss_qop_t,              /* qop_req */
                OM_uint32,              /* req_output_size */
                OM_uint32 *             /* max_input_size */
               );
 OM_uint32 gss_add_cred (
                OM_uint32 ,             /* minor_status */
                const gss_cred_id_t,    /* input_cred_handle */
                const gss_name_t,       /* desired_name */
                const gss_OID,          /* desired_mech */
                gss_cred_usage_t,       /* cred_usage */
                OM_uint32,              /* initiator_time_req */
                OM_uint32,              /* acceptor_time_req */
                gss_cred_id_t ,         /* output_cred_handle */
                gss_OID_set ,           /* actual_mechs */
                OM_uint32 ,             /* initiator_time_rec */
                OM_uint32 *             /* acceptor_time_rec */
               );
 OM_uint32 gss_inquire_cred_by_mech (
                OM_uint32 ,             /* minor_status */
                const gss_cred_id_t,    /* cred_handle */
                const gss_OID,          /* mech_type */
                gss_name_t ,            /* name */
                OM_uint32 ,             /* initiator_lifetime */
                OM_uint32 ,             /* acceptor_lifetime */
                gss_cred_usage_t *      /* cred_usage */
               );
 OM_uint32 gss_export_sec_context (
                OM_uint32 ,             /* minor_status */
                gss_ctx_id_t ,          /* context_handle */
                gss_buffer_t            /* interprocess_token */
               );
 OM_uint32 gss_import_sec_context (
                OM_uint32 ,             /* minor_status */
                const gss_buffer_t,     /* interprocess_token */
                gss_ctx_id_t *          /* context_handle */
               );

Wray Standards Track [Page 95] RFC 2744 GSS-API V2: C-bindings January 2000

 OM_uint32 gss_create_empty_oid_set (
                OM_uint32 ,             /* minor_status */
                gss_OID_set *           /* oid_set */
               );
 OM_uint32 gss_add_oid_set_member (
                OM_uint32 ,             /* minor_status */
                const gss_OID,          /* member_oid */
                gss_OID_set *           /* oid_set */
               );
 OM_uint32 gss_test_oid_set_member (
                OM_uint32 ,             /* minor_status */
                const gss_OID,          /* member */
                const gss_OID_set,      /* set */
                int *                   /* present */
               );
 OM_uint32 gss_inquire_names_for_mech (
                OM_uint32 ,             /* minor_status */
                const gss_OID,          /* mechanism */
                gss_OID_set *           /* name_types */
               );
 OM_uint32 gss_inquire_mechs_for_name (
                OM_uint32 ,             /* minor_status */
                const gss_name_t,       /* input_name */
                gss_OID_set *           /* mech_types */
               );
 OM_uint32 gss_canonicalize_name (
                OM_uint32 ,             /* minor_status */
                const gss_name_t,       /* input_name */
                const gss_OID,          /* mech_type */
                gss_name_t *            /* output_name */
               );
 OM_uint32 gss_duplicate_name (
                OM_uint32 ,             /* minor_status */
                const gss_name_t,       /* src_name */
                gss_name_t *            /* dest_name */
               );
 /*
  * The following routines are obsolete variants of gss_get_mic,
  * gss_verify_mic, gss_wrap and gss_unwrap.  They should be
  * provided by GSS-API V2 implementations for backwards
  * compatibility with V1 applications.  Distinct entrypoints

Wray Standards Track [Page 96] RFC 2744 GSS-API V2: C-bindings January 2000

  • (as opposed to #defines) should be provided, both to allow
  • GSS-API V1 applications to link against GSS-API V2

implementations,

  • and to retain the slight parameter type differences between the
  • obsolete versions of these routines and their current forms.
  • /
 OM_uint32 gss_sign
               (OM_uint32 ,        /* minor_status */
                gss_ctx_id_t,      /* context_handle */
                int,               /* qop_req */
                gss_buffer_t,      /* message_buffer */
                gss_buffer_t       /* message_token */
               );
 OM_uint32 gss_verify
               (OM_uint32 ,        /* minor_status */
                gss_ctx_id_t,      /* context_handle */
                gss_buffer_t,      /* message_buffer */
                gss_buffer_t,      /* token_buffer */
                int *              /* qop_state */
               );
 OM_uint32 gss_seal
               (OM_uint32 ,        /* minor_status */
                gss_ctx_id_t,      /* context_handle */
                int,               /* conf_req_flag */
                int,               /* qop_req */
                gss_buffer_t,      /* input_message_buffer */
                int ,              /* conf_state */
                gss_buffer_t       /* output_message_buffer */
               );
 OM_uint32 gss_unseal
               (OM_uint32 ,        /* minor_status */
                gss_ctx_id_t,      /* context_handle */
                gss_buffer_t,      /* input_message_buffer */
                gss_buffer_t,      /* output_message_buffer */
                int ,              /* conf_state */
                int *              /* qop_state */
               );
 #endif /* GSSAPI_H_ */

Wray Standards Track [Page 97] RFC 2744 GSS-API V2: C-bindings January 2000

Appendix B. Additional constraints for application binary portability

 The purpose of this C-bindings document is to encourage source-level
 portability of applications across GSS-API implementations on
 different platforms and atop different mechanisms.  Additional goals
 that have not been explicitly addressed by this document are link-
 time and run-time portability.
 Link-time portability provides the ability to compile an application
 against one implementation of GSS-API, and then link it against a
 different implementation on the same platform.  It is a stricter
 requirement than source-level portability.
 Run-time portability differs from link-time portability only on those
 platforms that implement dynamically loadable GSS-API
 implementations, but do not offer load-time symbol resolution. On
 such platforms, run-time portability is a stricter requirement than
 link-time portability, and will typically include the precise
 placement of the various GSS-API routines within library entrypoint
 vectors.
 Individual platforms will impose their own rules that must be
 followed to achieve link-time (and run-time, if different)
 portability.  In order to ensure either form of binary portability,
 an ABI specification must be written for GSS-API implementations on
 that platform.  However, it is recognized that there are some issues
 that are likely to be common to all such ABI specifications. This
 appendix is intended to be a repository for such common issues, and
 contains some suggestions that individual ABI specifications may
 choose to reference. Since machine architectures vary greatly, it may
 not be possible or desirable to follow these suggestions on all
 platforms.

B.1. Pointers

 While ANSI-C provides a single pointer type for each declared type,
 plus a single (void *) type, some platforms (notably those using
 segmented memory architectures) augment this with various modified
 pointer types (e.g. far pointers, near pointers). These language
 bindings assume ANSI-C, and thus do not address such non-standard
 implementations.  GSS-API implementations for such platforms must
 choose an appropriate memory model, and should use it consistently
 throughout.  For example, if a memory model is chosen that requires
 the use of far pointers when passing routine parameters, then far
 pointers should also be used within the structures defined by GSS-
 API.

Wray Standards Track [Page 98] RFC 2744 GSS-API V2: C-bindings January 2000

B.2. Internal structure alignment

 GSS-API defines several data-structures containing differently-sized
 fields.  An ABI specification should include a detailed description
 of how the fields of such structures are aligned, and if there is any
 internal padding in these data structures.  The use of compiler
 defaults for the platform is recommended.

B.3. Handle types

 The C bindings specify that the gss_cred_id_t and gss_ctx_id_t types
 should be implemented as either pointer or arithmetic types, and that
 if pointer types are used, care should be taken to ensure that two
 handles may be compared with the == operator. Note that ANSI-C does
 not guarantee that two pointer values may be compared with the ==
 operator unless either the two pointers point to members of a single
 array, or at least one of the pointers contains a NULL value.
 For binary portability, additional constraints are required. The
 following is an attempt at defining platform-independent constraints.
 The size of the handle type must be the same as sizeof(void *), using
 the appropriate memory model.
 The == operator for the chosen type must be a simple bit-wise
 comparison.  That is, for two in-memory handle objects h1 and h2, the
 boolean value of the expression
    (h1 == h2)
 should always be the same as the boolean value of the expression
    (memcmp(&h1, &h2, sizeof(h1)) == 0)
 The actual use of the type (void *) for handle types is discouraged,
 not for binary portability reasons, but since it effectively disables
 much of the compile-time type-checking that the compiler can
 otherwise perform, and is therefore not "programmer-friendly".  If a
 pointer implementation is desired, and if the platform's
 implementation of pointers permits, the handles should be implemented
 as pointers to distinct implementation-defined types.

B.4. The gss_name_t type

 The gss_name_t type, representing the internal name object, should be
 implemented as a pointer type.  The use of the (void *) type is
 discouraged as it does not allow the compiler to perform strong
 type-checking.  However, the pointer type chosen should be of the

Wray Standards Track [Page 99] RFC 2744 GSS-API V2: C-bindings January 2000

 same size as the (void *) type.  Provided this rule is obeyed, ABI
 specifications need not further constrain the implementation of
 gss_name_t objects.

B.5. The int and size_t types

 Some platforms may support differently sized implementations of the
 "int" and "size_t" types, perhaps chosen through compiler switches,
 and perhaps dependent on memory model.  An ABI specification for such
 a platform should include required implementations for these types.
 It is recommended that the default implementation (for the chosen
 memory model, if appropriate) is chosen.

B.6. Procedure-calling conventions

 Some platforms support a variety of different binary conventions for
 calling procedures.  Such conventions cover things like the format of
 the stack frame, the order in which the routine parameters are pushed
 onto the stack, whether or not a parameter count is pushed onto the
 stack, whether some argument(s) or return values are to be passed in
 registers, and whether the called routine or the caller is
 responsible for removing the stack frame on return.  For such
 platforms, an ABI specification should specify which calling
 convention is to be used for GSS-API implementations.

References

 [GSSAPI]    Linn, J., "Generic Security Service Application Program
             Interface Version 2, Update 1", RFC 2743, January 2000.
 [XOM]       OSI Object Management API Specification, Version 2.0 t",
             X.400 API Association & X/Open Company Limited, August
             24, 1990 Specification of datatypes and routines for
             manipulating information objects.

Author's Address

 John Wray
 Iris Associates
 5 Technology Park Drive,
 Westford, MA  01886
 USA
 Phone: +1-978-392-6689
 EMail: John_Wray@Iris.com

Wray Standards Track [Page 100] RFC 2744 GSS-API V2: C-bindings January 2000

Full Copyright Statement

 Copyright (C) The Internet Society (2000).  All Rights Reserved.
 This document and translations of it may be copied and furnished to
 others, and derivative works that comment on or otherwise explain it
 or assist in its implementation may be prepared, copied, published
 and distributed, in whole or in part, without restriction of any
 kind, provided that the above copyright notice and this paragraph are
 included on all such copies and derivative works.  However, this
 document itself may not be modified in any way, such as by removing
 the copyright notice or references to the Internet Society or other
 Internet organizations, except as needed for the purpose of
 developing Internet standards in which case the procedures for
 copyrights defined in the Internet Standards process must be
 followed, or as required to translate it into languages other than
 English.
 The limited permissions granted above are perpetual and will not be
 revoked by the Internet Society or its successors or assigns.
 This document and the information contained herein is provided on an
 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

 Funding for the RFC Editor function is currently provided by the
 Internet Society.

Wray Standards Track [Page 101]

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