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gssapi(3) [freebsd man page]

GSSAPI(3)						   BSD Library Functions Manual 						 GSSAPI(3)

gssapi -- Generic Security Services API LIBRARY
GSS-API Library (libgssapi, -lgssapi) SYNOPSIS
#include <gssapi/gssapi.h> DESCRIPTION
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 enhance- ments are integrated through invocation of services provided by the GSS-API. The GSS-API allows a caller application to authenticate a prin- cipal 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. 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 con- texts, acting as an agent or delegate of the initiator. This transfer of rights is termed delegation, and is achieved by creating a set of credentials, similar to those used by the initiating application, but which may be used by the responder. To establish and maintain the shared information that makes up the security context, certain GSS-API calls will return a token data structure, which is an opaque data type that may contain cryptographically protected data. The caller of such a GSS-API routine is responsible for transferring the token to the peer application, encapsulated if necessary in an application 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: integrity and data origin authentication, or confidentiality, integrity and data origin authentication to application data, which are treated by GSS-API as arbitrary octet-strings. An application transmitting a message that it wishes to protect will call the appropriate GSS-API routine (gss_get_mic or gss_wrap) to apply protection, specifying the appropriate security context, and send the resulting token to the receiving application. The receiver will pass the received token (and, in the case of data protected by gss_get_mic, the accompa- nying message-data) to the corresponding decoding routine (gss_verify_mic or gss_unwrap) to remove the protection and validate the data. d) At the completion of a communications session (which may extend across several transport connections), each application calls a GSS-API routine to delete the security context. Multiple contexts may also be used (either successively or simultaneously) within a single com- munications association, at the option of the applications. 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. GSS-API Credential-management Routines: gss_acquire_cred Assume a global identity; Obtain a GSS-API credential handle for pre-existing credentials. gss_add_cred Construct credentials incrementally gss_inquire_cred Obtain information about a credential gss_inquire_cred_by_mech Obtain per-mechanism information about a credential. gss_release_cred Discard a credential handle. GSS-API Context-Level Routines: gss_init_sec_context Initiate a security context with a peer application gss_accept_sec_context Accept a security context initiated by a peer application gss_delete_sec_context Discard a security context gss_process_context_token Process a token on a security context from a peer application gss_context_time Determine for how long a context will remain valid gss_inquire_context Obtain information about a security context gss_wrap_size_limit Determine token-size limit for gss_wrap(3) on a context gss_export_sec_context Transfer a security context to another process gss_import_sec_context Import a transferred context GSS-API Per-message Routines: gss_get_mic Calculate a cryptographic message integrity code (MIC) for a message; integrity service gss_verify_mic Check a MIC against a message; verify integrity of a received message gss_wrap Attach a MIC to a message, and optionally encrypt the message content; confidentiality service gss_unwrap Verify a message with attached MIC, and decrypt message content if necessary. GSS-API Name manipulation Routines: gss_import_name Convert a contiguous string name to internal-form gss_display_name Convert internal-form name to text gss_compare_name Compare two internal-form names gss_release_name Discard an internal-form name gss_inquire_names_for_mech List the name-types supported by the specified mechanism gss_inquire_mechs_for_name List mechanisms that support the specified name-type gss_canonicalize_name Convert an internal name to an MN gss_export_name Convert an MN to export form gss_duplicate_name Create a copy of an internal name GSS-API Miscellaneous Routines gss_add_oid_set_member Add an object identifier to a set gss_display_status Convert a GSS-API status code to text gss_indicate_mechs Determine available underlying authentication mechanisms gss_release_buffer Discard a buffer gss_release_oid_set Discard a set of object identifiers gss_create_empty_oid_set Create a set containing no object identifiers gss_test_oid_set_member Determines whether an object identifier is a member of a set. Individual GSS-API implementations may augment these routines by providing additional mechanism-specific routines if required functionality is not available from the generic forms. Applications are encouraged to use the generic routines wherever possible on portability grounds. STANDARDS
RFC 2743 Generic Security Service Application Program Interface Version 2, Update 1 RFC 2744 Generic Security Service API Version 2 : C-bindings HISTORY
The gssapi library first appeared in FreeBSD 7.0. AUTHORS
John Wray, Iris Associates COPYRIGHT
Copyright (C) The Internet Society (2000). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, pro- vided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organiza- tions, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. BSD
January 26, 2010 BSD
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