309 lines
		
	
	
		
			8.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			309 lines
		
	
	
		
			8.3 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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| 
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| #include "mech_locl.h"
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| 
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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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| 	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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| 	/*
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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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| 	
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| 	p++;
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| 	len--;
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| 		
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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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| 	/*
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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_oid->length = p[1];
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| 	p += 2;
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| 	len -= 2;
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| 	mech_oid->elements = p;
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| 	
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| 	return GSS_S_COMPLETE;
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| }		
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| 
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| static gss_OID_desc krb5_mechanism =
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|     {9, rk_UNCONST("\x2a\x86\x48\x86\xf7\x12\x01\x02\x02")};
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| static gss_OID_desc ntlm_mechanism =
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|     {10, rk_UNCONST("\x2b\x06\x01\x04\x01\x82\x37\x02\x02\x0a")};
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| static gss_OID_desc spnego_mechanism =
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|     {6, rk_UNCONST("\x2b\x06\x01\x05\x05\x02")};
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| 
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| static OM_uint32
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| choose_mech(const gss_buffer_t input, gss_OID mech_oid)
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| {
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| 	OM_uint32 status;
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| 
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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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| 
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| 	status = parse_header(input, mech_oid);
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| 	if (status == GSS_S_COMPLETE)
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| 	    return GSS_S_COMPLETE;
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| 
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| 	/*
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| 	 * Lets guess what mech is really is, callback function to mech ??
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| 	 */
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| 
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| 	if (input->length > 8 &&
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| 	    memcmp((const char *)input->value, "NTLMSSP\x00", 8) == 0)
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| 	{
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| 		*mech_oid = ntlm_mechanism;
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| 		return GSS_S_COMPLETE;
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| 	} else if (input->length != 0 &&
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| 		   ((const char *)input->value)[0] == 0x6E)
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| 	{
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| 		/* Could be a raw AP-REQ (check for APPLICATION tag) */
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| 		*mech_oid = krb5_mechanism;
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| 		return GSS_S_COMPLETE;
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| 	} else 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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| 		*mech_oid = spnego_mechanism;
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| 		return GSS_S_COMPLETE;
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| 	}
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| 	return status;
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| }
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| 
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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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|     const gss_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;
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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_cred_id_t acceptor_mc, delegated_mc;
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| 	gss_name_t src_mn;
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| 	gss_OID mech_ret_type = NULL;
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| 
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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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| 
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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 (*context_handle == GSS_C_NO_CONTEXT) {
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| 		gss_OID_desc mech_oid;
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| 
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| 		major_status = choose_mech(input_token, &mech_oid);
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| 		if (major_status != GSS_S_COMPLETE)
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| 			return major_status;
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| 
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| 		/*
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| 		 * Now that we have a mechanism, we can find the
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| 		 * implementation.
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| 		 */
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| 		ctx = malloc(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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| 		memset(ctx, 0, sizeof(struct _gss_context));
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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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| 			return (GSS_S_BAD_MECH);
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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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| 
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| 	if (cred) {
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| 		SLIST_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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| 			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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| 	delegated_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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| 	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, major_status, *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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| 
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| 	if (mech_type)
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| 	    *mech_type = mech_ret_type;
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| 
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| 	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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| 		struct _gss_name *name = _gss_make_name(m, src_mn);
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| 
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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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| 	} else if (src_mn) {
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| 		m->gm_release_name(minor_status, &src_mn);
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| 	}
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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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| 			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 (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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| 
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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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| 
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| 			dcred = malloc(sizeof(struct _gss_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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| 			SLIST_INIT(&dcred->gc_mc);
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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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| 			SLIST_INSERT_HEAD(&dcred->gc_mc, dmc, gmc_link);
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| 
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| 			*delegated_cred_handle = (gss_cred_id_t) dcred;
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| 		}
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| 	}
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| 
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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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