Internet draft J.Wray IETF Common Authentication Technology WG Digital Equipment Corporation <draft-ietf-cat-gssv2-cbind-00.txt> March 1995 Generic Security Service API Version 2 : C-bindings 1. STATUS OF THIS MEMO This document is an Internet Draft. Internet Drafts are working documents of the Internet Engineering Task Force (IETF), its Areas, and its Working Groups. Note that other groups may also distribute working documents as Internet Drafts. Internet Drafts are draft documents valid for a maximum of six months. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a "working draft" or "work in progress." Please check the I-D abstract listing contained in each Internet Draft directory to learn the current status of this or any other Internet Draft. Comments on this document should be sent to "cat-ietf@MIT.EDU", the IETF Common Authentication Technology WG discussion list. 2. ABSTRACT This draft document specifies C language bindings for Version 2 of the Generic Security Service Application Program Interface (GSS-API), which is described at a language-independent conceptual level in other drafts. 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. 3. 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. Wray Document Expiration: 31 August 1995 [Page 1]
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 a cryptographically protected opaque data type. 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. (c) Per-message services are invoked to apply either: (i) integrity and data origin authentication, or (ii) 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. Wray Document Expiration: 31 August 1995 [Page 2]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 (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. 4. 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 7. Table 4-1 GSS-API Credential-management Routines ROUTINE SECTION FUNCTION gss_acquire_cred 7.2 Assume a global identity; Obtain a GSS-API credential handle for pre-existing credentials. gss_inquire_cred 7.15 Obtain information about a credential. gss_release_cred 7.18 Discard a credential handle. Table 4-2 GSS-API Context-level Routines ROUTINE SECTION FUNCTION gss_init_sec_context 7.13 Initiate a security context with a peer application gss_accept_sec_context 7.1 Accept a security context initiated by a peer application gss_delete_sec_context 7.5 Discard a security context gss_process_context_token 7.16 Process a token on a security context from a peer application gss_context_time 7.4 Determine for how long a context will remain valid Wray Document Expiration: 31 August 1995 [Page 3]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 gss_inquire_context 7.14 Obtain information about a security context gss_wrap_size_limit 7.24 Determine token-size limit for gss_wrap on a context Table 4-3 GSS-API Per-message Routines ROUTINE SECTION FUNCTION gss_get_mic 7.9 Calculate a cryptographic Message Integrity Code (MIC) for a message; integrity service gss_verify_mic 7.22 Check a MIC against a message; verify integrity of a received message gss_wrap 7.23 Attach a MIC to a message, and optionally encrypt the message content; confidentiality service gss_unwrap 7.21 Verify a message with attached MIC, and decrypt message content if necessary. Table 4-4 GSS-API Support Routines ROUTINE SECTION FUNCTION SUPPORT ROUTINES gss_display_status 7.7 Convert a GSS-API status code to text gss_indicate_mechs 7.12 Determine available underlying authentication mechanisms gss_import_name 7.10 Convert a textual name to internal-form gss_display_name 7.6 Convert internal-form name to text Wray Document Expiration: 31 August 1995 [Page 4]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 gss_compare_name 7.3 Compare two internal-form names gss_release_name 7.19 Discard an internal-form name gss_release_oid_set 7.20 Discard a set of object identifiers gss_release_buffer 7.17 Discard a buffer gss_import_name_object 7.11 Create an internal-form name from a mechanism-specific name object gss_export_name_object 7.8 Create a mechanism-specific name object from an internal-form name 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. 5. DATA TYPES AND CALLING CONVENTIONS The following conventions are used by the GSS-API C-language bindings: 5.1. 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. Wray Document Expiration: 31 August 1995 [Page 5]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 5.2. String and similar data Many of the GSS-API routines take arguments and return values that describe contiguous multiple-byte data. 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 passed 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. 5.2.1. 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. 5.2.2. Character strings Certain multiple-word data items may be regarded as simple ISO Latin-1 character strings. An example of this is the input_name_buffer parameter to gss_import_name. Some GSS-API routines also return character strings. Character strings are passed between the application and the GSS-API using the gss_buffer_t datatype. The length field of a gss_buffer_desc object should only count valid printable characters within the value. In particular, no trailing NULL character should be included in the length count. 5.3. 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. A value of type gss_OID has the Wray Document Expiration: 31 August 1995 [Page 6]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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 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 following octal values: 53,14,2,207,163,7,5. GSS-API implementations should provide constant gss_OID values to allow callers 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 5.9). 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. The gss_OID_desc datatype is equivalent to the X/Open OM_object_identifier datatype[XOM]. 5.4. Object Identifier Sets Certain GSS-API procedures take parameters of the type gss_OID_set. This type represents one or more object identifiers (section 5.3). 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. Storage associated with gss_OID_set values returned to the application by the GSS-API may be deallocated by the gss_release_oid_set routine. 5.5. 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 Wray Document Expiration: 31 August 1995 [Page 7]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 be taken to ensure that two gss_cred_id_t values may be compared with the == operator. Credentials describe a principal, and give their holder the ability to act as that principal. The GSS-API does not make the actual credentials available to applications; instead the credential handle is used to identify a particular credential, held internally by GSS- API or the underlying 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 GSSAPI implementations are free to determine such default behavior as appropriate to the mechanism, the following default behavior by these routines is recommended for portability: (a) gss_init_sec_context (i) If there is only a single principal capable of initiating security contexts that the application is authorized to act on behalf of, then that principal shall be used, otherwise (ii) If the platform maintains a concept of a default network-identity, and if the application is authorized to act on behalf of that identity for the purpose if initiating security contects, then the principal corresponding to that identity shall be used, otherwise (iii) If the platform maintains a concept of a default local identity, and provides a means to map local identities into network-identities, and if the application is authorized to act on behalf of the network-identity image of the default local identity for the purpose of initiating security contexts, then the principal corresponding to that identity shall be used, otherwise (iv) A user-configurable default identity should be used. (b) gss_accept_sec_context (i) If there is only a single authorized principal identity capable of accepting security contexts, then that principal shall be used, otherwise (ii) 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, then that principal identity shall be used, Wray Document Expiration: 31 August 1995 [Page 8]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 otherwise (iii) If the mechanism supports context acceptance by any principal, and mutual authentication was not requested, any principal that the application is authorized to accept security contexts under may be used, otherwise (iv) 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. 5.6. 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. 5.7. 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 byte-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. 5.8. Status values One or more status codes are returned by each GSS-API routine. Two distinct sorts of status codes are returned. These are termed GSS status codes and Mechanism status codes. 5.8.1. 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 Wray Document Expiration: 31 August 1995 [Page 9]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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. 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 5-1 Calling Errors Name Value in Meaning Field 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 Document Expiration: 31 August 1995 [Page 10]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 Table 5-2 Routine Errors Name Value in Meaning Field 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_SIG 6 A token had an invalid signature or MIC GSS_S_NO_CRED 7 No credentials were supplied 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 provide Table 5-3 Supplementary Status Bits Name Bit Number Meaning GSS_S_CONTINUE_NEEDED 0 (LSB) 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 Wray Document Expiration: 31 August 1995 [Page 11]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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 routine status values only. 5.8.2. 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 set 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. The GSS 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 status code will provide more details about the error. Wray Document Expiration: 31 August 1995 [Page 12]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 5.9. 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. Three distinct representations are defined for names: (a) A printable form, for presentation to a user (b) An internal form, for presentation at the API (c) Optional mechanism-specific forms. The syntax of a printable name is defined by the GSS-API implementation, and may be dependent on local system configuration, or on individual user preference. The internal form provides a canonical representation of the name that is independent of configuration. The mechanism-specific forms are provided to simplify porting of existing mechanism-specific applications to the GSS-API. Any application that uses mechanism-specific name-forms is inherently non-portable to other mechanisms, and may not be portable to other implementations of the same mechanism. A given GSS-API implementation may support names drawn from multiple namespaces. In such an implementation, the internal form of the name must include fields that identify the namespace from which the name is drawn. The namespace from which a printable name is drawn is specified by an accompanying object identifier. Routines (gss_import_name and gss_display_name) are provided to convert names between their printable 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 preferred syntax for each supported name- type. Comparison of internal-form names is accomplished via the gss_compare_names routine. 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. 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 a name. Wray Document Expiration: 31 August 1995 [Page 13]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 5.10. Channel Bindings GSS-API supports the use of user-specified tags to identify a given context to the peer application. These tags are 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 DARPA Internet address type GSS_C_AF_IMPLINK ARPAnet IMP address type (eg IP) 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 (eg X.25) 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 X25 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 form is used. When not otherwise specified, addresses should be specified in network byte-order. Wray Document Expiration: 31 August 1995 [Page 14]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 Conceptually, the GSS-API concatenates the initiator_addrtype, initiator_address, acceptor_addrtype, acceptor_address and application_data to form an octet string. The mechanism signs this octet string, and binds the signature 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 signature is calculated in the same way. The calculated signature is compared with that found in the token, and if the signatures 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 signature); 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. Therefore, portable applications should ensure that they provide either correct information for the address fields, or should omit addressing information, and specify GSS_C_AF_NULLADDR as the address-types. 5.11. 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. 5.11.1. 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. 5.11.2. Integer types (input) Individual parameter documentation lists values to be used to indicate default actions. 5.11.3. Integer types (output) Specify NULL as the value for the pointer. Wray Document Expiration: 31 August 1995 [Page 15]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 5.11.4. Pointer types Specify NULL as the value. 5.11.5. Object IDs Specify GSS_C_NO_OID as the value. 5.11.6. Object ID Sets Specify GSS_C_NO_OID_SET as the value. 5.11.7. Channel Bindings Specify GSS_C_NO_CHANNEL_BINDINGS to indicate that channel bindings are not to be used. 6. ADDITIONAL CONTROLS This section discusses the optional services that a context initiator may request of the GSS-API at context establishment. All these services are requested by setting flags 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. 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, Wray Document Expiration: 31 August 1995 [Page 16]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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. 6.1. 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. 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 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 provide at the explicit request of the application. 6.2. 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 initator. 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. Wray Document Expiration: 31 August 1995 [Page 17]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 The initiating application is informed as to whether or not mutual authentication is being requested of the context acceptor. 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. 6.3. 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 checksum of an application message, and returns that checksum 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 checksum of an application message, and places both the checksum and the message in a token. The application should pass the token to the peer application, which presents it to gss_unwrap to extract the message. 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. Contexts that do not claim to provide replay detection may still set this bit if the duplicate message is processed immediately after the original, with no intervening messages. 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. Wray Document Expiration: 31 August 1995 [Page 18]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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. 6.4. Anonymous Authentication In certain situations, an application may wish to initiate the authentication process to authenticate a peer, without revealing its own identity. For 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 be refused. However, 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 estalished 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_NAMETYPE_ANONYMOUS. This gss_OID value should refer to a gss_OID_desc object containing the value {4, (void *)"}. 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 ">". Wray Document Expiration: 31 August 1995 [Page 19]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 6.5. 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. Some mechanisms may specify that the confidentiality service is optional, and that implementors of the mechanism need not provide it, often because of legal restrictions on confidentiality protection. For such mechanisms, it it possible that while the context initiator's GSS-API implementation supports confidentiality, the context acceptor's implementation may not. In this case, the status return from gss_init_sec_context may indicate that the confidentiality service is available, whereas in fact it is not, since the acceptor will be unable to apply confidentility protection to messages, or to process confidentiality-protected messages. If context establishment requires the transmission of a token from acceptor to initiator, the mechanism is encouraged to use this token to indicate to the initiating GSS-API whether the acceptor supports confidentiality, so that correct service information may be delivered to the initiating application. For such a mechanism, the ret_flags returned from the initial invocation of gss_init_sec_context should indicate that confidentiality protection is available if the initiating GSS-API implementation supports it, but the ret_flags returned from the final invocation should indicate that the service is unavailable if the acceptor does not provide confidentiality support. 7. 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. Wray Document Expiration: 31 August 1995 [Page 20]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 7.1. gss_accept_sec_context OM_uint32 gss_accept_sec_context ( OM_uint32 * minor_status, gss_ctx_id_t * context_handle, gss_cred_id_t verifier_cred_handle, gss_buffer_t input_token_buffer 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) 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. The values returned via the src_name, time_rec, mech_type and delegated_cred_handle parameters are not defined unless the routine returns GSS_S_COMPLETE. 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. 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. verifier_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 Wray Document Expiration: 31 August 1995 [Page 21]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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. 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. 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 Wray Document Expiration: 31 August 1995 [Page 22]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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 an anonymous internal name. False - The initiator has been authenticated normally. 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. If not needed, specify NULL. minor_status integer, modify Mechanism specific status code. Function value: Wray Document Expiration: 31 August 1995 [Page 23]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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_accept_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 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 signature. 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. Wray Document Expiration: 31 August 1995 [Page 24]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 7.2. gss_acquire_cred OM_uint32 gss_acquire_cred ( OM_uint32 * minor_status, gss_name_t desired_name, OM_uint32 time_req, gss_OID_set desired_mechs, gss_cred_usage_t cred_usage, gss_cred_id_t * output_cred_handle, gss_OID_set * actual_mechs, OM_int32 * time_rec) 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. 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. If credential acquisition is time-consuming for a mechanism, the mechanism may chooses 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. Parameters: desired_name gss_name_t, read Name of principal whose credential should be acquired time_req integer, read number of seconds that credentials should remain valid desired_mechs Set of Object IDs, read Wray Document Expiration: 31 August 1995 [Page 25]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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. actual_mechs Set of Object IDs, modify, optional The set of mechanisms for which the credential is valid. 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 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. Wray Document Expiration: 31 August 1995 [Page 26]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 7.3. gss_compare_name OM_uint32 gss_compare_name ( OM_uint32 * minor_status, gss_name_t name1, 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 name_equal boolean, modify True - names refer to same entity False - 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 type contained within either name1 or name2 was unrecognized, or the names were of incomparable types. GSS_S_BAD_NAME One or both of name1 or name2 was ill-formed Wray Document Expiration: 31 August 1995 [Page 27]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 7.4. gss_context_time OM_uint32 gss_context_time ( OM_uint32 * minor_status, 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_CREDENTIALS_EXPIRED The context is recognized, but associated credentials have expired GSS_S_NO_CONTEXT The context_handle parameter did not identify a valid context 7.5. 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) Wray Document Expiration: 31 August 1995 [Page 28]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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. 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. Parameters: minor_status integer, modify Mechanism specific status code. context_handle gss_ctx_id_t, modify context handle identifying context to delete. 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. Function value: GSS status code: GSS_S_COMPLETE Successful completion GSS_S_NO_CONTEXT No valid context was supplied Wray Document Expiration: 31 August 1995 [Page 29]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 7.6. gss_display_name OM_uint32 gss_display_name ( OM_uint32 * minor_status, 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_NAMETYPE_ANONYMOUS as the output_name_type, and a textual name that is syntactically distinct from all valid supported printable names in output_name_buffer. 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 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. Specify NULL if not required. Function value: GSS status code: GSS_S_COMPLETE Successful completion GSS_S_BAD_NAMETYPE The type of input_name was not recognized GSS_S_BAD_NAME input_name was ill-formed Wray Document Expiration: 31 August 1995 [Page 30]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 7.7. gss_display_status OM_uint32 gss_display_status ( OM_uint32 * minor_status, OM_uint32 status_value, int status_type, 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 errors, applications may need to call gss_display_status multiple times, each call generating a single text string. The message_context parameter is used to indicate which error message should be extracted from a given status_value; message_context should be initialized to 0, and gss_display_status will return a non-zero value if there are further messages to extract. 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 caller on first call. If further messages are contained in the status_value parameter, message_context will be non-zero on return, and this value should be passed back to subsequent calls, along with the same status_value, status_type and mech_type parameters. Wray Document Expiration: 31 August 1995 [Page 31]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 status_string buffer, character string, modify textual interpretation of the status_value 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. 7.8. gss_export_name_object OM_uint32 gss_export_name_object ( OM_uint32 * minor_status, gss_name_t input_name, gss_OID desired_name_type, void ** output_name) Purpose: Provided to simplify the porting of a mechanism-specific application to the GSS-API. Allows a GSS-API internal name to be converted into a mechanism-specific name object. Applications invoking the gss_export_name_object routine are unlikely to be portable to other mechanisms, and may not be portable to other implementations of the same mechanism. Parameters: minor_status integer, modify Mechanism specific status code input_name gss_name_t, read The GSS-API internal name to be converted desired_name_type OID, read The name-type corresponding to the desired type of name object. The mechanism must define an OID to identify its internal Wray Document Expiration: 31 August 1995 [Page 32]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 name objects. output_name Pointer to any, modify The mechanism-specific name object corresponding to the provided input_name. Function value: GSS status code GSS_S_COMPLETE Successful completion GSS_S_BAD_NAMETYPE The speicified nametype is unrecognized or unsupported GSS_S_BAD_NAME The provided name was either not a valid GSS-API internal name, or it could not be converted to a mechanism-specific name of the desired type. 7.9. gss_get_mic OM_uint32 gss_get_mic ( OM_uint32 * minor_status, gss_ctx_id_t context_handle, gss_qop_t qop_req, gss_buffer_t message_buffer, gss_buffer_t msg_token) Purpose: Generates a cryptographic signature for the supplied message, and places the signature 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. 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 Wray Document Expiration: 31 August 1995 [Page 33]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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 Function value: GSS status code: GSS_S_COMPLETE Successful completion GSS_S_CONTEXT_EXPIRED The context has already expired GSS_S_CREDENTIALS_EXPIRED The context is recognized, but associated credentials have 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. 7.10. gss_import_name OM_uint32 gss_import_name ( OM_uint32 * minor_status, gss_buffer_t input_name_buffer, gss_OID input_name_type, gss_name_t * output_name) Purpose: Convert a printable name to internal form. Parameters: Wray Document Expiration: 31 August 1995 [Page 34]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 minor_status integer, modify Mechanism specific status code input_name_buffer buffer, character-string, read buffer containing printable 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 local system-specific printable syntax, or an OID registered by the GSS-API implementation to name a particular namespace. output_name gss_name_t, modify returned name in internal form 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 7.11. gss_import_name_object OM_uint32 gss_import_name_object ( OM_uint32 * minor_status, void * input_name, gss_OID input_name_type, gss_name_t * output_name) Purpose: Provided to simplify the porting of a mechanism-specific application to the GSS-API. Allows a mechanism-specific name object to be converted into a GSS-API internal name. Applications invoking the gss_import_name_object routine are unlikely to be portable to other mechanisms, and may not be portable to other implementations of the same mechanism. Wray Document Expiration: 31 August 1995 [Page 35]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 Parameters: minor_status integer, modify Mechanism specific status code input_name Pointer to any, read The mechanism-specific name object to be imported input_name_type OID, read The name-type of the name object. The mechanism must define an OID to identify its internal name objects. output_name gss_name_t, modify The GSS-API internal name-form corresponding to the provided input_name. Function value: GSS status code GSS_S_COMPLETE Successful completion GSS_S_BAD_NAMETYPE The speicified nametype is unrecognized or unsupported GSS_S_BAD_NAME The provided name was not a valid object of the stated name-type. 7.12. gss_indicate_mechs OM_uint32 gss_indicate_mechs ( OM_uint32 * minor_status, gss_OID_set * mech_set) Purpose: Allows an application to determine which underlying security mechanisms are available. Parameters: minor_status integer, modify Mechanism specific status code. Wray Document Expiration: 31 August 1995 [Page 36]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 mech_set set of Object IDs, modify set of implementation-supported mechanisms. The returned gss_OID_set value will be a pointer into static storage, and should be treated as read-only by the caller. Function value: GSS status code: GSS_S_COMPLETE Successful completion 7.13. gss_init_sec_context OM_uint32 gss_init_sec_context ( OM_uint32 * minor_status, gss_cred_id_t claimant_cred_handle, gss_ctx_id_t * context_handle, gss_name_t target_name, gss_OID mech_type, OM_uint32 req_flags, OM_uint32 time_req, gss_channel_bindings_t input_chan_bindings, 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 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 Wray Document Expiration: 31 August 1995 [Page 37]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 reply token is received from the peer application, passing the reply token to gss_init_sec_context via the input_token parameters. Whenever the routine returns a major status that includes the value GSS_S_CONTINUE_NEEDED, the values returned via the actual_mech_type, and time_rec parameters are not defined, and the value returned via the ret_flags parameter should contain the value 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). Parameters: minor_status integer, modify Mechanism specific status code. claimant_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 initator 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. 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 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 Wray Document Expiration: 31 August 1995 [Page 38]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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_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. Specify NULL if not required. Wray Document Expiration: 31 August 1995 [Page 39]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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. 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: GSS_C_DELEG_FLAG True - Credentials were delegated to the remote peer False - No credentials were delegated GSS_C_MUTUAL_FLAG True - Remote peer has been asked to authenticated itself False - Remote peer has not been asked to 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. False - Per-message integrity service unavailable. GSS_C_ANON_FLAG Wray Document Expiration: 31 August 1995 [Page 40]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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. time_rec integer, modify, optional number of seconds for which the context will remain valid. If the implementation does not support credential 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 thecontext, 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 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 signature, or a signature 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. Wray Document Expiration: 31 August 1995 [Page 41]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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. 7.14. gss_inquire_context OM_uint32 gss_inquire_context ( OM_uint32 * minor_status, 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. 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. Wray Document Expiration: 31 August 1995 [Page 42]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 Specify NULL if not required. targ_name gss_name_t, modify, optional The name of the context acceptor. Specify NULL if not required. lifetime_rec 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. mech_type gss_OID, modify, optional The security mechanism providing the context. Specify NULL if not required. 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 Wray Document Expiration: 31 August 1995 [Page 43]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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 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. locally_initiated Boolean, modify True if the invoking application is the context initiator. Specify NULL if not required. open Boolean, modify True if the context is fully established; false 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. GSS_S_CONTEXT_EXPIRED The context has expired. If the lifetime_rec parameter was requested, it will be set to 0. Wray Document Expiration: 31 August 1995 [Page 44]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 7.15. gss_inquire_cred OM_uint32 gss_inquire_cred ( OM_uint32 * minor_status, 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. The caller must already have obtained a handle that refers to the 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. 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. mechanisms gss_OID_set, modify, optional Set of mechanisms supported by the credential. Specify NULL if not required. Function value: Wray Document Expiration: 31 August 1995 [Page 45]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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. 7.16. gss_process_context_token OM_uint32 gss_process_context_token ( OM_uint32 * minor_status, gss_ctx_id_t context_handle, gss_buffer_t token_buffer, gss_buffer_t output_token) Purpose: Provides a way to pass a token to the security service. Usually, tokens are associated either with context establishment (when they would be passed to gss_init_sec_context or gss_accept_sec_context) or with per-message security service (when they would be passed to gss_verify_mic or gss_unwrap). Occasionally, tokens may be received at other times, and gss_process_context_token allows such tokens to be passed to the underlying security service for processing. At present, such additional tokens may only be generated by gss_delete_sec_context. GSS-API implementation may use this service to implement deletion of the security context. 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 Wray Document Expiration: 31 August 1995 [Page 46]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 output_token buffer, opaque, modify A token that the application should send to the peer. If no token need be sent, GSS-API will set the length field to zero. 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 7.17. gss_release_buffer OM_uint32 gss_release_buffer ( OM_uint32 * minor_status, gss_buffer_t buffer) Purpose: Free storage associated with a buffer format name. 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 buffer parameter. 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 Wray Document Expiration: 31 August 1995 [Page 47]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 GSS_S_COMPLETE Successful completion 7.18. 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 process. When all processes have released a credential, it will be deleted. Parameters: cred_handle gss_cred_id_t, modify, optional Buffer containing opaque credential handle. 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. Wray Document Expiration: 31 August 1995 [Page 48]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 7.19. gss_release_name OM_uint32 gss_release_name ( OM_uint32 * minor_status, gss_name_t * name) Purpose: Free GSSAPI-allocated storage by associated with an internal form name. 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 7.20. gss_release_oid_set OM_uint32 gss_release_oid_set ( OM_uint32 * minor_status, gss_OID_set * set) Purpose: Free storage associated with a gss_OID_set object. The storage must have been allocated by a GSS-API routine. Parameters: minor_status integer, modify Mechanism specific status code set Set of Object IDs, modify The storage associated with the gss_OID_set Wray Document Expiration: 31 August 1995 [Page 49]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 will be deleted. Function value: GSS status code GSS_S_COMPLETE Successful completion 7.21. gss_unwrap OM_uint32 gss_unwrap ( 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, gss_qop_t * qop_state) Purpose: Converts a message previously protected by gss_wrap back to a usable form, verifying the embedded signature. 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. 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 conf_state boolean, modify, optional True - Confidentiality and integrity protection were used False - Inteegrity service only was used Wray Document Expiration: 31 August 1995 [Page 50]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 Specify NULL if not required qop_state gss_qop_t, modify, optional Quality of protection gained from signature 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 signature was incorrect GSS_S_DUPLICATE_TOKEN The token was valid, and contained a correct signature for the message, but it had already been processed GSS_S_OLD_TOKEN The token was valid, and contained a correct signature for the message, but it is too old to check for duplication. GSS_S_UNSEQ_TOKEN The token was valid, and contained a correct signature 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 signature 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_CREDENTIALS_EXPIRED The context is recognized, but associated credentials have expired GSS_S_NO_CONTEXT The context_handle parameter did not identify a valid context Wray Document Expiration: 31 August 1995 [Page 51]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 7.22. gss_verify_mic OM_uint32 gss_verify_mic ( OM_uint32 * minor_status, gss_ctx_id_t context_handle, gss_buffer_t message_buffer, gss_buffer_t token_buffer, gss_qop_t * qop_state) Purpose: Verifies that a cryptographic signature, 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. 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, optionalo quality of protection gained from signature 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 signature was incorrect GSS_S_DUPLICATE_TOKEN The token was valid, and contained a correct signature for the message, but it had already been processed GSS_S_OLD_TOKEN The token was valid, and contained a correct signature for the message, but it is too old to Wray Document Expiration: 31 August 1995 [Page 52]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 check for duplication. GSS_S_UNSEQ_TOKEN The token was valid, and contained a correct signature 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 signature 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_CREDENTIALS_EXPIRED The context is recognized, but associated credentials have expired GSS_S_NO_CONTEXT The context_handle parameter did not identify a valid context 7.23. gss_wrap OM_uint32 gss_wrap ( OM_uint32 * minor_status, gss_ctx_id_t context_handle, int conf_req_flag, gss_qop_t qop_req gss_buffer_t input_message_buffer, int * conf_state, gss_buffer_t output_message_buffer) Purpose: Cryptographically signs and optionally encrypts the specified input_message. The output_message contains both the signature and the message. The qop_req parameter allows a choice between several cryptographic algorithms, if supported by the chosen mechanism. Parameters: minor_status integer, modify Mechanism specific status code. context_handle gss_ctx_id_t, read Identifies the context on which the message Wray Document Expiration: 31 August 1995 [Page 53]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 will be sent conf_req_flag boolean, read True - Both confidentiality and integrity services are requested False - 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 True - Confidentiality, data origin authentication and integrity services have been applied False - 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 Function value: GSS status code: GSS_S_COMPLETE Successful completion GSS_S_CONTEXT_EXPIRED The context has already expired GSS_S_CREDENTIALS_EXPIRED The context is recognized, but associated credentials have 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. Wray Document Expiration: 31 August 1995 [Page 54]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 7.24. gss_wrap_size_limit OM_uint32 gss_wrap_size_limit ( OM_uint32 * minor_status, 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. Successful completion of this call does not guarantee that gss_wrap will be able to protect a message of length max_input_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 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 Wray Document Expiration: 31 August 1995 [Page 55]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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. Wray Document Expiration: 31 August 1995 [Page 56]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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> /* * First, define the three platform-dependent pointer 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; #else /* * We can't use X/Open definitions, so roll our own. Wray Document Expiration: 31 August 1995 [Page 57]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 */ 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 (pending resolution * of ongoing discussions). */ typedef OM_uint32 gss_qop_t; typedef int gss_cred_usage_t; /* * Flag bits for context-level services. */ #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 /* * Credential usage options Wray Document Expiration: 31 August 1995 [Page 58]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 */ #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 #define GSS_C_AF_NULLADDR 255 /* * Various Null values */ #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 Wray Document Expiration: 31 August 1995 [Page 59]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 * 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 either reserve a value (for example zero, * as assumed here) to mean "default protection", or * alternatively may simply equate GSS_C_QOP_DEFAULT to a specific * explicit QOP value. However, a value of 0 should always be * interpreted by a GSSAPI 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 * {4, (void *)"}, and GSS_C_NAMETYPE_ANONYMOUS * should be initialized to point to that gss_OID_desc. */ extern gss_OID GSS_C_NAMETYPE_ANONYMOUS; /* 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 #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 GSSAPI so that it now evaluates its argument * only once. Wray Document Expiration: 31 August 1995 [Page 60]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 */ #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 << GSS_C_ROUTINE_ERROR_OFFSET) #define GSS_S_BAD_SIG (6ul << GSS_C_ROUTINE_ERROR_OFFSET) #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) /* * 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)) Wray Document Expiration: 31 August 1995 [Page 61]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 /* * Finally, function prototypes for the GSS-API routines. */ OM_uint32 gss_acquire_cred (OM_uint32*, /* minor_status */ gss_name_t, /* desired_name */ OM_uint32, /* time_req */ 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 */ gss_cred_id_t, /* claimant_cred_handle */ gss_ctx_id_t*, /* context_handle */ gss_name_t, /* target_name */ gss_OID, /* mech_type */ OM_uint32, /* req_flags */ OM_uint32, /* time_req */ gss_channel_bindings_t, /* input_chan_bindings */ 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 */ gss_cred_id_t, /* verifier_cred_handle */ gss_buffer_t, /* input_token_buffer */ 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 */ ); Wray Document Expiration: 31 August 1995 [Page 62]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 OM_uint32 gss_process_context_token (OM_uint32*, /* minor_status */ gss_ctx_id_t, /* context_handle */ gss_buffer_t, /* token_buffer */ gss_buffer_t /* output_token */ ); 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 */ gss_ctx_id_t, /* context_handle */ OM_uint32* /* time_rec */ ); OM_uint32 gss_get_mic (OM_uint32*, /* minor_status */ gss_ctx_id_t, /* context_handle */ gss_qop_t, /* qop_req */ gss_buffer_t, /* message_buffer */ gss_buffer_t /* message_token */ ); OM_uint32 gss_verify_mic (OM_uint32*, /* minor_status */ gss_ctx_id_t, /* context_handle */ gss_buffer_t, /* message_buffer */ gss_buffer_t, /* token_buffer */ gss_qop_t* /* qop_state */ ); OM_uint32 gss_wrap (OM_uint32*, /* minor_status */ gss_ctx_id_t, /* context_handle */ int, /* conf_req_flag */ gss_qop_t, /* qop_req */ gss_buffer_t, /* input_message_buffer */ int*, /* conf_state */ gss_buffer_t /* output_message_buffer */ ); OM_uint32 gss_unwrap (OM_uint32*, /* minor_status */ gss_ctx_id_t, /* context_handle */ gss_buffer_t, /* input_message_buffer */ Wray Document Expiration: 31 August 1995 [Page 63]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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 */ 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 */ gss_name_t, /* name1 */ gss_name_t, /* name2 */ int* /* name_equal */ ); OM_uint32 gss_display_name (OM_uint32*, /* minor_status */ 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 */ gss_buffer_t, /* input_name_buffer */ gss_OID, /* input_name_type */ gss_name_t* /* output_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 */ ); Wray Document Expiration: 31 August 1995 [Page 64]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 OM_uint32 gss_release_oid_set (OM_uint32*, /* minor_status */ gss_OID_set* /* set */ ); OM_uint32 gss_inquire_cred (OM_uint32 *, /* minor_status */ gss_cred_id_t, /* cred_handle */ gss_name_t *, /* name */ OM_uint32 *, /* lifetime */ gss_cred_usage_t *, /* cred_usage */ gss_OID_set * /* mechanisms */ ); /* * The following routines are obsolete variants of gss_get_mic, * gss_wrap, gss_verify_mic and gss_unwrap. They should be * provided by GSSAPI V2 implementations for backwards * compatibility with V1 applications. Distinct entrypoints * (as opposed to #defines) should be provided, to allow GSSAPI * V1 applications to link against GSSAPI V2 implementations. */ 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 */ ); Wray Document Expiration: 31 August 1995 [Page 65]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 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 Document Expiration: 31 August 1995 [Page 66]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 APPENDIX B. Routines for further discussion The following convenience routines are presented for discussion. They are not currently part of the GSS-API. They provide support services for Object Identifiers and OID sets. B.1. 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. Function value: GSS status code GSS_S_COMPLETE Successful completion Wray Document Expiration: 31 August 1995 [Page 67]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 B.2. gss_add_oid_set_member OM_uint32 gss_add_oid_set_member ( OM_uint32 * minor_status, 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. Parameters: minor_status integer, modify Mechanism specific status code 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 objectidentifier should be inserted. Function value: GSS status code GSS_S_COMPLETE Successful completion B.3. gss_test_oid_set_member OM_uint32 gss_test_oid_set_member ( OM_uint32 * minor_status, gss_OID member, 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 Wray Document Expiration: 31 August 1995 [Page 68]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 gss_inquire_cred. 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 True if the specified OID is a member of the set, flase if not. Function value: GSS status code GSS_S_COMPLETE Successful completion B.4. gss_release_oid OM_uint32 gss_release_oid ( OM_uint32 * minor_status, gss_OID * oid) Purpose: Discard an OID. This routine is provided for completeness only. While some of the GSS-API routines return OIDs, these routines are currently documented as returning pointers to structures maintained in static storage. gss_release_oid will recognise any of the GSS- API's own OID values, and will silently ignore attempts to free these OIDs; for other OIDs it will call the C free() routine for both the OID data and the descriptor. This allows applications to freely mix their own heap-allocated OID values with OIDs returned by GSS-API. Parameters: minor_status integer, modify Mechanism specific status code oid Object ID, modify Wray Document Expiration: 31 August 1995 [Page 69]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 The object identifier to be freed. Function value: GSS status code GSS_S_COMPLETE Successful completion Wray Document Expiration: 31 August 1995 [Page 70]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 APPENDIX C. 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 recognised 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. C.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 Document Expiration: 31 August 1995 [Page 71]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 C.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. C.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 the additional constraints are required. The following is an attempt at defining platform-independent constraints. (a) The size of the handle type must be the same as sizeof(void *), using the appropriate memory model. (b) 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) (c) 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. C.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 same size as the (void *) type. Provided this rule is obeyed, ABI Wray Document Expiration: 31 August 1995 [Page 72]
INTERNET-DRAFT GSS-API V2 - C bindings March 1995 specifications need not further constrain the implementation of gss_name_t objects. C.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 approriate) is chosen. REFERENCES [GSSAPI] J. Linn, "Generic Security Service Application Program Interface, Version 2", Internet-Draft draft-ietf-cat- gssv2-00, November 1994. (This Internet-Draft, like all other Internet-Drafts, is not an archival document and is subject to change or deletion. It is available at the time of this writing by anonymous ftp from ds.internic.net, directory internet-drafts. Would-be readers should check for successor Internet-Draft versions or Internet RFCs before relying on this document.) [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 Internet email: Wray@tuxedo.enet.dec.com Digital Equipment Corporation Telephone: +1-508-486-5210 550 King Street, LKG2-2/Z7 Littleton, MA 01460 USA Wray Document Expiration: 31 August 1995 [Page 73]
