1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2008 Doug Rabson
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31 #include <gssapi/gssapi.h>
32 #include <stdlib.h>
33 #include <string.h>
34
35 #include "utils.h"
36
37 OM_uint32
gss_decapsulate_token(const gss_buffer_t input_token,gss_OID oid,gss_buffer_t output_token)38 gss_decapsulate_token(const gss_buffer_t input_token, gss_OID oid,
39 gss_buffer_t output_token)
40 {
41 unsigned char *p = input_token->value;
42 size_t len = input_token->length;
43 size_t a, b;
44 gss_OID_desc mech_oid;
45
46 _gss_buffer_zero(output_token);
47
48 /*
49 * Token must start with [APPLICATION 0] SEQUENCE.
50 */
51 if (len == 0 || *p != 0x60)
52 return (GSS_S_DEFECTIVE_TOKEN);
53 p++;
54 len--;
55
56 /*
57 * Decode the length and make sure it agrees with the
58 * token length.
59 */
60 if (len == 0)
61 return (GSS_S_DEFECTIVE_TOKEN);
62 if ((*p & 0x80) == 0) {
63 a = *p;
64 p++;
65 len--;
66 } else {
67 b = *p & 0x7f;
68 p++;
69 len--;
70 if (len < b)
71 return (GSS_S_DEFECTIVE_TOKEN);
72 a = 0;
73 while (b) {
74 a = (a << 8) | *p;
75 p++;
76 len--;
77 b--;
78 }
79 }
80 if (a != len)
81 return (GSS_S_DEFECTIVE_TOKEN);
82
83 /*
84 * Decode the OID for the mechanism. Simplify life by
85 * assuming that the OID length is less than 128 bytes.
86 */
87 if (len < 2 || *p != 0x06)
88 return (GSS_S_DEFECTIVE_TOKEN);
89 if ((p[1] & 0x80) || p[1] > (len - 2))
90 return (GSS_S_DEFECTIVE_TOKEN);
91 mech_oid.length = p[1];
92 p += 2;
93 len -= 2;
94 mech_oid.elements = p;
95
96 if (!gss_oid_equal(&mech_oid, oid))
97 return (GSS_S_FAILURE);
98
99 p += mech_oid.length;
100 len -= mech_oid.length;
101
102 output_token->length = len;
103 output_token->value = malloc(len);
104 if (!output_token->value)
105 return (GSS_S_DEFECTIVE_TOKEN);
106 memcpy(output_token->value, p, len);
107
108 return (GSS_S_COMPLETE);
109 }
110