1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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
29 #include <gssapi/gssapi.h>
30 #include <stdlib.h>
31 #include <string.h>
32
33 #include "utils.h"
34
35 OM_uint32
gss_decapsulate_token(const gss_buffer_t input_token,gss_OID oid,gss_buffer_t output_token)36 gss_decapsulate_token(const gss_buffer_t input_token, gss_OID oid,
37 gss_buffer_t output_token)
38 {
39 unsigned char *p = input_token->value;
40 size_t len = input_token->length;
41 size_t a, b;
42 gss_OID_desc mech_oid;
43
44 _gss_buffer_zero(output_token);
45
46 /*
47 * Token must start with [APPLICATION 0] SEQUENCE.
48 */
49 if (len == 0 || *p != 0x60)
50 return (GSS_S_DEFECTIVE_TOKEN);
51 p++;
52 len--;
53
54 /*
55 * Decode the length and make sure it agrees with the
56 * token length.
57 */
58 if (len == 0)
59 return (GSS_S_DEFECTIVE_TOKEN);
60 if ((*p & 0x80) == 0) {
61 a = *p;
62 p++;
63 len--;
64 } else {
65 b = *p & 0x7f;
66 p++;
67 len--;
68 if (len < b)
69 return (GSS_S_DEFECTIVE_TOKEN);
70 a = 0;
71 while (b) {
72 a = (a << 8) | *p;
73 p++;
74 len--;
75 b--;
76 }
77 }
78 if (a != len)
79 return (GSS_S_DEFECTIVE_TOKEN);
80
81 /*
82 * Decode the OID for the mechanism. Simplify life by
83 * assuming that the OID length is less than 128 bytes.
84 */
85 if (len < 2 || *p != 0x06)
86 return (GSS_S_DEFECTIVE_TOKEN);
87 if ((p[1] & 0x80) || p[1] > (len - 2))
88 return (GSS_S_DEFECTIVE_TOKEN);
89 mech_oid.length = p[1];
90 p += 2;
91 len -= 2;
92 mech_oid.elements = p;
93
94 if (!gss_oid_equal(&mech_oid, oid))
95 return (GSS_S_FAILURE);
96
97 p += mech_oid.length;
98 len -= mech_oid.length;
99
100 output_token->length = len;
101 output_token->value = malloc(len);
102 if (!output_token->value)
103 return (GSS_S_DEFECTIVE_TOKEN);
104 memcpy(output_token->value, p, len);
105
106 return (GSS_S_COMPLETE);
107 }
108