417 lines
13 KiB
C
417 lines
13 KiB
C
/*-
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* Copyright (c) 2005 Doug Rabson
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD: src/lib/libgssapi/gss_accept_sec_context.c,v 1.1 2005/12/29 14:40:20 dfr Exp $
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*/
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#include "mech_locl.h"
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static OM_uint32
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parse_header(const gss_buffer_t input_token, gss_OID *mech_oid)
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{
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gss_OID_desc mech;
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unsigned char *p = input_token->value;
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size_t len = input_token->length;
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size_t a, b;
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/*
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* Token must start with [APPLICATION 0] SEQUENCE.
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* But if it doesn't assume it is DCE-STYLE Kerberos!
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*/
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if (len == 0)
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return (GSS_S_DEFECTIVE_TOKEN);
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p++;
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len--;
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/*
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* Decode the length and make sure it agrees with the
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* token length.
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*/
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if (len == 0)
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return (GSS_S_DEFECTIVE_TOKEN);
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if ((*p & 0x80) == 0) {
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a = *p;
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p++;
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len--;
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} else {
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b = *p & 0x7f;
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p++;
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len--;
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if (len < b)
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return (GSS_S_DEFECTIVE_TOKEN);
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a = 0;
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while (b) {
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a = (a << 8) | *p;
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p++;
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len--;
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b--;
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}
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}
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if (a != len)
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return (GSS_S_DEFECTIVE_TOKEN);
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/*
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* Decode the OID for the mechanism. Simplify life by
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* assuming that the OID length is less than 128 bytes.
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*/
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if (len < 2 || *p != 0x06)
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return (GSS_S_DEFECTIVE_TOKEN);
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if ((p[1] & 0x80) || p[1] > (len - 2))
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return (GSS_S_DEFECTIVE_TOKEN);
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mech.length = p[1];
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p += 2;
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len -= 2;
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mech.elements = p;
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*mech_oid = _gss_mg_support_mechanism(&mech);
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if (*mech_oid == GSS_C_NO_OID)
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return GSS_S_BAD_MECH;
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return GSS_S_COMPLETE;
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}
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static gss_OID
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choose_mech(const gss_buffer_t input)
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{
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OM_uint32 status;
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gss_OID mech_oid = GSS_C_NO_OID;
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/*
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* First try to parse the gssapi token header and see if it's a
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* correct header, use that in the first hand.
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*/
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status = parse_header(input, &mech_oid);
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if (status == GSS_S_COMPLETE && mech_oid != GSS_C_NO_OID)
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return mech_oid;
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if (input->length == 0) {
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/*
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* There is the a wierd mode of SPNEGO (in CIFS and
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* SASL GSS-SPENGO where the first token is zero
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* length and the acceptor returns a mech_list, lets
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* hope that is what is happening now.
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*
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* http://msdn.microsoft.com/en-us/library/cc213114.aspx
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* "NegTokenInit2 Variation for Server-Initiation"
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*/
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return &__gss_spnego_mechanism_oid_desc;
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}
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_gss_mg_log(10, "Don't have client request mech");
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return mech_oid;
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}
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GSSAPI_LIB_FUNCTION OM_uint32 GSSAPI_LIB_CALL
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gss_accept_sec_context(OM_uint32 *minor_status,
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gss_ctx_id_t *context_handle,
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gss_const_cred_id_t acceptor_cred_handle,
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const gss_buffer_t input_token,
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const gss_channel_bindings_t input_chan_bindings,
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gss_name_t *src_name,
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gss_OID *mech_type,
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gss_buffer_t output_token,
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OM_uint32 *ret_flags,
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OM_uint32 *time_rec,
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gss_cred_id_t *delegated_cred_handle)
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{
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OM_uint32 major_status, mech_ret_flags, junk;
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gssapi_mech_interface m = NULL;
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struct _gss_context *ctx = (struct _gss_context *) *context_handle;
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struct _gss_cred *cred = (struct _gss_cred *) acceptor_cred_handle;
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struct _gss_mechanism_cred *mc;
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gss_buffer_desc defective_token_error;
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gss_const_cred_id_t acceptor_mc;
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gss_cred_id_t delegated_mc = GSS_C_NO_CREDENTIAL;
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gss_name_t src_mn = GSS_C_NO_NAME;
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gss_OID mech_ret_type = GSS_C_NO_OID;
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int initial = !!(*context_handle == GSS_C_NO_CONTEXT);
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defective_token_error.length = 0;
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defective_token_error.value = NULL;
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*minor_status = 0;
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if (src_name)
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*src_name = GSS_C_NO_NAME;
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if (mech_type)
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*mech_type = GSS_C_NO_OID;
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if (ret_flags)
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*ret_flags = 0;
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if (time_rec)
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*time_rec = 0;
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if (delegated_cred_handle)
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*delegated_cred_handle = GSS_C_NO_CREDENTIAL;
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_mg_buffer_zero(output_token);
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/*
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* If this is the first call (*context_handle is NULL), we must
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* parse the input token to figure out the mechanism to use.
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*/
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if (initial) {
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gss_OID mech_oid;
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mech_oid = choose_mech(input_token);
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/*
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* If mech_oid == GSS_C_NO_OID then the mech is non-standard
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* and we have to try all mechs (that we have a cred element
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* for, if we have a cred).
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*/
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ctx = calloc(1, sizeof(struct _gss_context));
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if (!ctx) {
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*minor_status = ENOMEM;
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return (GSS_S_DEFECTIVE_TOKEN);
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}
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if (mech_oid != GSS_C_NO_OID) {
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m = ctx->gc_mech = __gss_get_mechanism(mech_oid);
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if (!m) {
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free(ctx);
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_gss_mg_log(10, "mechanism client used is unknown");
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return (GSS_S_BAD_MECH);
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}
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}
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*context_handle = (gss_ctx_id_t) ctx;
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} else {
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m = ctx->gc_mech;
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}
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if (initial && !m && acceptor_cred_handle == GSS_C_NO_CREDENTIAL) {
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/*
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* No header, not a standard mechanism. Try all the mechanisms
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* (because default credential).
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*/
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struct _gss_mech_switch *ms;
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_gss_load_mech();
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acceptor_mc = GSS_C_NO_CREDENTIAL;
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HEIM_TAILQ_FOREACH(ms, &_gss_mechs, gm_link) {
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m = &ms->gm_mech;
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mech_ret_flags = 0;
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major_status = m->gm_accept_sec_context(minor_status,
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&ctx->gc_ctx,
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acceptor_mc,
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input_token,
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input_chan_bindings,
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&src_mn,
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&mech_ret_type,
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output_token,
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&mech_ret_flags,
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time_rec,
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&delegated_mc);
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if (major_status == GSS_S_DEFECTIVE_TOKEN) {
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/*
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* Try to retain and output one error token for
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* GSS_S_DEFECTIVE_TOKEN. The first one.
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*/
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if (output_token->length &&
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defective_token_error.length == 0) {
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defective_token_error = *output_token;
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output_token->length = 0;
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output_token->value = NULL;
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}
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gss_release_buffer(&junk, output_token);
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continue;
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}
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gss_release_buffer(&junk, &defective_token_error);
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ctx->gc_mech = m;
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goto got_one;
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}
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m = NULL;
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acceptor_mc = GSS_C_NO_CREDENTIAL;
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} else if (initial && !m) {
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/*
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* No header, not a standard mechanism. Try all the mechanisms
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* that we have a credential element for if we have a
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* non-default credential.
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*/
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HEIM_TAILQ_FOREACH(mc, &cred->gc_mc, gmc_link) {
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m = mc->gmc_mech;
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acceptor_mc = (m->gm_flags & GM_USE_MG_CRED) ?
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acceptor_cred_handle : mc->gmc_cred;
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mech_ret_flags = 0;
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major_status = m->gm_accept_sec_context(minor_status,
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&ctx->gc_ctx,
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acceptor_mc,
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input_token,
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input_chan_bindings,
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&src_mn,
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&mech_ret_type,
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output_token,
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&mech_ret_flags,
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time_rec,
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&delegated_mc);
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if (major_status == GSS_S_DEFECTIVE_TOKEN) {
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if (output_token->length &&
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defective_token_error.length == 0) {
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defective_token_error = *output_token;
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output_token->length = 0;
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output_token->value = NULL;
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}
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gss_release_buffer(&junk, output_token);
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continue;
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}
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gss_release_buffer(&junk, &defective_token_error);
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ctx->gc_mech = m;
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goto got_one;
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}
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m = NULL;
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acceptor_mc = GSS_C_NO_CREDENTIAL;
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}
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if (m == NULL) {
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gss_delete_sec_context(&junk, context_handle, NULL);
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_gss_mg_log(10, "No mechanism accepted the non-standard initial security context token");
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*output_token = defective_token_error;
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return GSS_S_BAD_MECH;
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}
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if (m->gm_flags & GM_USE_MG_CRED) {
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acceptor_mc = acceptor_cred_handle;
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} else if (cred) {
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HEIM_TAILQ_FOREACH(mc, &cred->gc_mc, gmc_link)
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if (mc->gmc_mech == m)
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break;
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if (!mc) {
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gss_delete_sec_context(&junk, context_handle, NULL);
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_gss_mg_log(10, "gss-asc: client sent mech %s "
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"but no credential was matching",
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m->gm_name);
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HEIM_TAILQ_FOREACH(mc, &cred->gc_mc, gmc_link)
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_gss_mg_log(10, "gss-asc: available creds were %s", mc->gmc_mech->gm_name);
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return (GSS_S_BAD_MECH);
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}
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acceptor_mc = mc->gmc_cred;
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} else {
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acceptor_mc = GSS_C_NO_CREDENTIAL;
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}
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mech_ret_flags = 0;
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major_status = m->gm_accept_sec_context(minor_status,
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&ctx->gc_ctx,
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acceptor_mc,
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input_token,
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input_chan_bindings,
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&src_mn,
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&mech_ret_type,
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output_token,
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&mech_ret_flags,
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time_rec,
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&delegated_mc);
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got_one:
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if (major_status != GSS_S_COMPLETE &&
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major_status != GSS_S_CONTINUE_NEEDED)
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{
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_gss_mg_error(m, *minor_status);
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gss_delete_sec_context(&junk, context_handle, NULL);
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return (major_status);
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}
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if (mech_type)
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*mech_type = mech_ret_type;
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if (src_name && src_mn && (ctx->gc_mech->gm_flags & GM_USE_MG_NAME)) {
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/* Negotiation mechanisms use mechglue names as names */
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*src_name = src_mn;
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src_mn = GSS_C_NO_NAME;
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} else if (src_name && src_mn) {
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/*
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* Make a new name and mark it as an MN.
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*
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* Note that _gss_create_name() consumes `src_mn' but doesn't
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* take a pointer, so it can't set it to GSS_C_NO_NAME.
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*/
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struct _gss_name *name = _gss_create_name(src_mn, m);
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if (!name) {
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m->gm_release_name(minor_status, &src_mn);
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gss_delete_sec_context(&junk, context_handle, NULL);
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return (GSS_S_FAILURE);
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}
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*src_name = (gss_name_t) name;
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src_mn = GSS_C_NO_NAME;
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} else if (src_mn) {
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m->gm_release_name(minor_status, &src_mn);
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}
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if (mech_ret_flags & GSS_C_DELEG_FLAG) {
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if (!delegated_cred_handle) {
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if (m->gm_flags & GM_USE_MG_CRED)
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gss_release_cred(minor_status, &delegated_mc);
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else
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m->gm_release_cred(minor_status, &delegated_mc);
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mech_ret_flags &=
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~(GSS_C_DELEG_FLAG|GSS_C_DELEG_POLICY_FLAG);
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} else if ((m->gm_flags & GM_USE_MG_CRED) != 0) {
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/*
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* If credential is uses mechglue cred, assume it
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* returns one too.
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*/
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*delegated_cred_handle = delegated_mc;
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} else if (gss_oid_equal(mech_ret_type, &m->gm_mech_oid) == 0) {
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/*
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* If the returned mech_type is not the same
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* as the mech, assume its pseudo mech type
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* and the returned type is already a
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* mech-glue object
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*/
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*delegated_cred_handle = delegated_mc;
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} else if (delegated_mc) {
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struct _gss_cred *dcred;
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struct _gss_mechanism_cred *dmc;
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dcred = _gss_mg_alloc_cred();
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if (!dcred) {
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*minor_status = ENOMEM;
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gss_delete_sec_context(&junk, context_handle, NULL);
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return (GSS_S_FAILURE);
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}
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dmc = malloc(sizeof(struct _gss_mechanism_cred));
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if (!dmc) {
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free(dcred);
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*minor_status = ENOMEM;
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gss_delete_sec_context(&junk, context_handle, NULL);
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return (GSS_S_FAILURE);
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}
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dmc->gmc_mech = m;
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dmc->gmc_mech_oid = &m->gm_mech_oid;
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dmc->gmc_cred = delegated_mc;
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HEIM_TAILQ_INSERT_TAIL(&dcred->gc_mc, dmc, gmc_link);
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*delegated_cred_handle = (gss_cred_id_t) dcred;
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}
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}
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_gss_mg_log(10, "gss-asc: return %d/%d", (int)major_status, (int)*minor_status);
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if (ret_flags)
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*ret_flags = mech_ret_flags;
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return (major_status);
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}
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