freebsd-skq/lib/libgssapi/gss_decapsulate_token.c

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/*-
* Copyright (c) 2008 Doug Rabson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <gssapi/gssapi.h>
#include <stdlib.h>
#include <string.h>
#include "utils.h"
OM_uint32
gss_decapsulate_token(const gss_buffer_t input_token, gss_OID oid,
gss_buffer_t output_token)
{
unsigned char *p = input_token->value;
size_t len = input_token->length;
size_t a, b;
gss_OID_desc mech_oid;
_gss_buffer_zero(output_token);
/*
* Token must start with [APPLICATION 0] SEQUENCE.
*/
if (len == 0 || *p != 0x60)
return (GSS_S_DEFECTIVE_TOKEN);
p++;
len--;
/*
* Decode the length and make sure it agrees with the
* token length.
*/
if (len == 0)
return (GSS_S_DEFECTIVE_TOKEN);
if ((*p & 0x80) == 0) {
a = *p;
p++;
len--;
} else {
b = *p & 0x7f;
p++;
len--;
if (len < b)
return (GSS_S_DEFECTIVE_TOKEN);
a = 0;
while (b) {
a = (a << 8) | *p;
p++;
len--;
b--;
}
}
if (a != len)
return (GSS_S_DEFECTIVE_TOKEN);
/*
* Decode the OID for the mechanism. Simplify life by
* assuming that the OID length is less than 128 bytes.
*/
if (len < 2 || *p != 0x06)
return (GSS_S_DEFECTIVE_TOKEN);
if ((p[1] & 0x80) || p[1] > (len - 2))
return (GSS_S_DEFECTIVE_TOKEN);
mech_oid.length = p[1];
p += 2;
len -= 2;
mech_oid.elements = p;
if (!gss_oid_equal(&mech_oid, oid))
return (GSS_S_FAILURE);
p += mech_oid.length;
len -= mech_oid.length;
output_token->length = len;
output_token->value = malloc(len);
if (!output_token->value)
return (GSS_S_DEFECTIVE_TOKEN);
memcpy(output_token->value, p, len);
return (GSS_S_COMPLETE);
}