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gss_accept_sec_context(3gss) [opensolaris man page]

gss_accept_sec_context(3GSS)			  Generic Security Services API Library Functions		      gss_accept_sec_context(3GSS)

NAME
gss_accept_sec_context - accept a security context initiated by a peer application SYNOPSIS
cc [ flag... ] file... -lgss [ library... ] #include <gssapi/gssapi.h> OM_uint32 gss_accept_sec_context(OM_uint32 *minor_status, gss_ctx_id_t *context_handle, const gss_cred_id_t acceptor_cred_handle, const gss_buffer_t input_token, const gss_channel_bindings_t input_chan_bindings, const gss_name_t * src_name, gss_OID * mech_type, gss_buffer_t output_token, OM_uint32 *ret_flags, OM_uint32 * time_rec, gss_cred_id_t *delegated_cred_handle); PARAMETERS
The parameter descriptions for gss_accept_sec_context() follow: minor_status The status code returned by the underlying mechanism. context_handle The context handle to return to the initiator. This should be set to GSS_C_NO_CONTEXT before the loop begins. acceptor_cred_handle The handle for the credentials acquired by the acceptor, typically through gss_acquire_cred(). It may be initialized to GSS_C_NO_CRE- DENTIAL to indicate a default credential to use. If no default credential is defined, the function returns GSS_C_NO_CRED. input_token_buffer Token received from the context initiative. input_chan_bindings Optional application-specified bindings. Allows application to securely bind channel identification information to the security con- text. Set to GSS_C_NO_CHANNEL_BINDINGS if you do not want to use channel bindings. src_name The authenticated name of the context initiator. After use, this name should be deallocated by passing it to gss_release_name(). See gss_release_name(3GSS). If not required, specify NULL. mech_type The security mechanism used. Set to NULL if it does not matter which mechanism is used. output_token The token to send to the acceptor. Initialize it to GSS_C_NO_BUFFER before the function is called (or its length field set to zero). If the length is zero, no token need be sent. ret_flags Contains various independent flags, each of which indicates that the context supports a specific service option. If not needed, specify NULL. Test the returned bit-mask ret_flags value against its symbolic name to determine if the given option is supported by the con- text. ret_flags may contain one of the following values: GSS_C_DELEG_FLAG If true, delegated credentials are available by means of the delegated_cred_handle parameter. If false, no credentials were dele- gated. GSS_C_MUTUAL_FLAG If true, a remote peer asked for mutual authentication. If false, no remote peer asked for mutual authentication. GSS_C_REPLAY_FLAG If true, replay of protected messages will be detected. If false, replayed messages will not be detected. GSS_C_SEQUENCE_FLAG If true, out of sequence protected messages will be detected. If false, they will not be detected. GSS_C_CONF_FLAG If true, confidentiality service may be invoked by calling the gss_wrap() routine. If false, no confidentiality service is avail- able by means of gss_wrap(). gss_wrap() will provide message encapsulation, data-origin authentication and integrity services only. GSS_C_INTEG_FLAG If true, integrity service may be invoked by calling either the gss_get_mic(3GSS) or the gss_wrap(3GSS) routine. If false, per-mes- sage integrity service is not available. GSS_C_ANON_FLAG If true, the initiator does not wish to be authenticated. The src_name parameter, if requested, contains an anonymous internal name. If false, the initiator has been authenticated normally. GSS_C_PROT_READY_FLAG If true, the protection services specified by the states of GSS_C_CONF_FLAG and GSS_C_INTEG_FLAG are available if the accompanying major status return value is either GSS_S_COMPLETE or GSS_S_CONTINUE_NEEDED. If false, the protection services are available only if the accompanying major status return value is GSS_S_COMPLETE. GSS_C_TRANS_FLAG If true, the resultant security context may be transferred to other processes by means of a call to gss_export_sec_context(3GSS). If false, the security context cannot be transferred. time_rec The number of sections for which the context will remain value Specify NULL if not required. delegated_cred_handle The credential value for credentials received from the context's initiator. It is valid only if the initiator has requested that the acceptor act as a proxy: that is, if the ret_flag argument resolves to GSS_C_DELEG_FLAG. DESCRIPTION
The gss_accept_sec_context() function allows a remotely initiated security context between the application and a remote peer to be estab- lished. The routine may return an output_token, which should be transferred to the peer application, where the peer application will present it to gss_init_sec_context(). See gss_init_sec_context(3GSS). 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() by means of the input_token parameters. Portable applications should be constructed to use the token length and return status to determine whether to send or to wait for a token. Whenever gss_accept_sec_context() returns a major status that includes the value GSS_S_CONTINUE_NEEDED, the context is not fully estab- lished, and the following restrictions apply to the output parameters: o The value returned by means of the time_rec parameter is undefined. o Unless the accompanying ret_flags parameter contains the bit GSS_C_PROT_READY_FLAG, which indicates that per-message services may be applied in advance of a successful completion status, the value returned by the mech_type parameter may be undefined until gss_accept_sec_context() returns a major status value of GSS_S_COMPLETE. The values of the GSS_C_DELEG_FLAG, GSS_C_MUTUAL_FLAG, GSS_C_REPLAY_FLAG, GSS_C_SEQUENCE_FLAG, GSS_C_CONF_FLAG, GSS_C_INTEG_FLAG and GSS_C_ANON_FLAG bits returned by means of the ret_flags parameter are values that would be valid if context establishment were to succeed. The values of the GSS_C_PROT_READY_FLAG and GSS_C_TRANS_FLAG bits within ret_flags indicate the actual state at the time gss_accept_sec_context() returns, whether or not the context is fully established. However, applications should not rely on this behavior, as GSS_C_PROT_READY_FLAG was not defined in Version 1 of the GSS-API. Instead, applications should be prepared to use per-message services after a successful context establishment, based upon the GSS_C_INTEG_FLAG and GSS_C_CONF_FLAG values. All other bits within the ret_flags argument are set to zero. While gss_accept_sec_context() returns GSS_S_CONTINUE_NEEDED, the values returned by means of the the ret_flags argument indicate the ser- vices available from the established context. If the initial call of gss_accept_sec_context() fails, no context object is created, and the value of the context_handle parameter is set to GSS_C_NO_CONTEXT. In the event of a failure on a subsequent call, the security context and the context_handle parameter are left untouched for the application to delete using gss_delete_sec_context(3GSS). During context establish- ment, the informational status bits GSS_S_OLD_TOKEN and GSS_S_DUPLICATE_TOKEN indicate fatal errors; GSS-API mechanisms always return them in association with a routine error of GSS_S_FAILURE. This pairing requirement did not exist in version 1 of the GSS-API specification, so applications that wish to run over version 1 implementations must special-case these codes. ERRORS
gss_accept_sec_context() may return the following status codes: GSS_S_COMPLETE Successful completion. GSS_S_CONTINUE_NEEDED 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 Consistency checks performed on the input_token failed. GSS_S_DEFECTIVE_CREDENTIAL 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 than those specified by means of the input_chan_bindings parameter. GSS_S_NO_CONTEXT The supplied context handle did not refer to a valid context. GSS_S_BAD_SIG The input_token contains an invalid MIC. GSS_S_OLD_TOKEN The input_token was too old. This is a fatal error while establishing context. GSS_S_DUPLICATE_TOKEN The input_token is valid, but it is duplicate of a token already processed. This is a fatal error while establishing context. GSS_S_BAD_MECH The token received specified a mechanism that is not supported by the implementation or the provided creden- tial. GSS_S_FAILURE The underlying mechanism detected an error for which no specific GSS status code is defined. The mechanism- specific status code reported by means of the minor_status parameter details the error condition. EXAMPLES
Example 1 Invoking gss_accept_sec_context() Within a Loop A typical portable caller should always invoke gss_accept_sec_context() within a loop: gss_ctx_id_t context_hdl = GSS_C_NO_CONTEXT; do { receive_token_from_peer(input_token); maj_stat = gss_accept_sec_context(&min_stat, &context_hdl, cred_hdl, input_token, input_bindings, &client_name, &mech_type, output_token, &ret_flags, &time_rec, &deleg_cred); if (GSS_ERROR(maj_stat)) { report_error(maj_stat, min_stat); }; if (output_token->length != 0) { send_token_to_peer(output_token); gss_release_buffer(&min_stat, output_token); }; if (GSS_ERROR(maj_stat)) { if (context_hdl != GSS_C_NO_CONTEXT) gss_delete_sec_context(&min_stat, &context_hdl, GSS_C_NO_BUFFER); break; }; } while (maj_stat & GSS_S_CONTINUE_NEEDED); /* Check client_name authorization */ ... (void) gss_release_name(&min_stat, &client_name); /* Use and/or store delegated credential */ ... (void) gss_release_cred(&min_stat, &deleg_cred); ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |MT-Level |Safe | +-----------------------------+-----------------------------+ SEE ALSO
gss_delete_sec_context(3GSS), gss_export_sec_context(3GSS), gss_get_mic(3GSS), gss_init_sec_context(3GSS), gss_release_cred(3GSS), gss_release_name(3GSS), gss_store_cred(3GSS), gss_wrap(3GSS), attributes(5) Solaris Security for Developers Guide SunOS 5.11 22 May 2006 gss_accept_sec_context(3GSS)
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