1/*
2 * Copyright (c) 1997 - 2003 Kungliga Tekniska H�gskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include "krb5/gsskrb5_locl.h"
35
36RCSID("$Id: 8003.c 18334 2006-10-07 22:16:04Z lha $");
37
38krb5_error_code
39_gsskrb5_encode_om_uint32(OM_uint32 n, u_char *p)
40{
41  p[0] = (n >> 0)  & 0xFF;
42  p[1] = (n >> 8)  & 0xFF;
43  p[2] = (n >> 16) & 0xFF;
44  p[3] = (n >> 24) & 0xFF;
45  return 0;
46}
47
48krb5_error_code
49_gsskrb5_encode_be_om_uint32(OM_uint32 n, u_char *p)
50{
51  p[0] = (n >> 24) & 0xFF;
52  p[1] = (n >> 16) & 0xFF;
53  p[2] = (n >> 8)  & 0xFF;
54  p[3] = (n >> 0)  & 0xFF;
55  return 0;
56}
57
58krb5_error_code
59_gsskrb5_decode_om_uint32(const void *ptr, OM_uint32 *n)
60{
61    const u_char *p = ptr;
62    *n = (p[0] << 0) | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
63    return 0;
64}
65
66krb5_error_code
67_gsskrb5_decode_be_om_uint32(const void *ptr, OM_uint32 *n)
68{
69    const u_char *p = ptr;
70    *n = (p[0] <<24) | (p[1] << 16) | (p[2] << 8) | (p[3] << 0);
71    return 0;
72}
73
74static krb5_error_code
75hash_input_chan_bindings (const gss_channel_bindings_t b,
76			  u_char *p)
77{
78  u_char num[4];
79  MD5_CTX md5;
80
81  MD5_Init(&md5);
82  _gsskrb5_encode_om_uint32 (b->initiator_addrtype, num);
83  MD5_Update (&md5, num, sizeof(num));
84  _gsskrb5_encode_om_uint32 (b->initiator_address.length, num);
85  MD5_Update (&md5, num, sizeof(num));
86  if (b->initiator_address.length)
87    MD5_Update (&md5,
88		b->initiator_address.value,
89		b->initiator_address.length);
90  _gsskrb5_encode_om_uint32 (b->acceptor_addrtype, num);
91  MD5_Update (&md5, num, sizeof(num));
92  _gsskrb5_encode_om_uint32 (b->acceptor_address.length, num);
93  MD5_Update (&md5, num, sizeof(num));
94  if (b->acceptor_address.length)
95    MD5_Update (&md5,
96		b->acceptor_address.value,
97		b->acceptor_address.length);
98  _gsskrb5_encode_om_uint32 (b->application_data.length, num);
99  MD5_Update (&md5, num, sizeof(num));
100  if (b->application_data.length)
101    MD5_Update (&md5,
102		b->application_data.value,
103		b->application_data.length);
104  MD5_Final (p, &md5);
105  return 0;
106}
107
108/*
109 * create a checksum over the chanel bindings in
110 * `input_chan_bindings', `flags' and `fwd_data' and return it in
111 * `result'
112 */
113
114OM_uint32
115_gsskrb5_create_8003_checksum (
116		      OM_uint32 *minor_status,
117		      const gss_channel_bindings_t input_chan_bindings,
118		      OM_uint32 flags,
119		      const krb5_data *fwd_data,
120		      Checksum *result)
121{
122    u_char *p;
123
124    /*
125     * see rfc1964 (section 1.1.1 (Initial Token), and the checksum value
126     * field's format) */
127    result->cksumtype = CKSUMTYPE_GSSAPI;
128    if (fwd_data->length > 0 && (flags & GSS_C_DELEG_FLAG))
129	result->checksum.length = 24 + 4 + fwd_data->length;
130    else
131	result->checksum.length = 24;
132    result->checksum.data   = malloc (result->checksum.length);
133    if (result->checksum.data == NULL) {
134	*minor_status = ENOMEM;
135	return GSS_S_FAILURE;
136    }
137
138    p = result->checksum.data;
139    _gsskrb5_encode_om_uint32 (16, p);
140    p += 4;
141    if (input_chan_bindings == GSS_C_NO_CHANNEL_BINDINGS) {
142	memset (p, 0, 16);
143    } else {
144	hash_input_chan_bindings (input_chan_bindings, p);
145    }
146    p += 16;
147    _gsskrb5_encode_om_uint32 (flags, p);
148    p += 4;
149
150    if (fwd_data->length > 0 && (flags & GSS_C_DELEG_FLAG)) {
151
152	*p++ = (1 >> 0) & 0xFF;                   /* DlgOpt */ /* == 1 */
153	*p++ = (1 >> 8) & 0xFF;                   /* DlgOpt */ /* == 0 */
154	*p++ = (fwd_data->length >> 0) & 0xFF;    /* Dlgth  */
155	*p++ = (fwd_data->length >> 8) & 0xFF;    /* Dlgth  */
156	memcpy(p, (unsigned char *) fwd_data->data, fwd_data->length);
157
158	p += fwd_data->length;
159    }
160
161    return GSS_S_COMPLETE;
162}
163
164/*
165 * verify the checksum in `cksum' over `input_chan_bindings'
166 * returning  `flags' and `fwd_data'
167 */
168
169OM_uint32
170_gsskrb5_verify_8003_checksum(
171		      OM_uint32 *minor_status,
172		      const gss_channel_bindings_t input_chan_bindings,
173		      const Checksum *cksum,
174		      OM_uint32 *flags,
175		      krb5_data *fwd_data)
176{
177    unsigned char hash[16];
178    unsigned char *p;
179    OM_uint32 length;
180    int DlgOpt;
181    static unsigned char zeros[16];
182
183    if (cksum == NULL) {
184	*minor_status = 0;
185	return GSS_S_BAD_BINDINGS;
186    }
187
188    /* XXX should handle checksums > 24 bytes */
189    if(cksum->cksumtype != CKSUMTYPE_GSSAPI || cksum->checksum.length < 24) {
190	*minor_status = 0;
191	return GSS_S_BAD_BINDINGS;
192    }
193
194    p = cksum->checksum.data;
195    _gsskrb5_decode_om_uint32(p, &length);
196    if(length != sizeof(hash)) {
197	*minor_status = 0;
198	return GSS_S_BAD_BINDINGS;
199    }
200
201    p += 4;
202
203    if (input_chan_bindings != GSS_C_NO_CHANNEL_BINDINGS
204	&& memcmp(p, zeros, sizeof(zeros)) != 0) {
205	if(hash_input_chan_bindings(input_chan_bindings, hash) != 0) {
206	    *minor_status = 0;
207	    return GSS_S_BAD_BINDINGS;
208	}
209	if(memcmp(hash, p, sizeof(hash)) != 0) {
210	    *minor_status = 0;
211	    return GSS_S_BAD_BINDINGS;
212	}
213    }
214
215    p += sizeof(hash);
216
217    _gsskrb5_decode_om_uint32(p, flags);
218    p += 4;
219
220    if (cksum->checksum.length > 24 && (*flags & GSS_C_DELEG_FLAG)) {
221	if(cksum->checksum.length < 28) {
222	    *minor_status = 0;
223	    return GSS_S_BAD_BINDINGS;
224	}
225
226	DlgOpt = (p[0] << 0) | (p[1] << 8);
227	p += 2;
228	if (DlgOpt != 1) {
229	    *minor_status = 0;
230	    return GSS_S_BAD_BINDINGS;
231	}
232
233	fwd_data->length = (p[0] << 0) | (p[1] << 8);
234	p += 2;
235	if(cksum->checksum.length < 28 + fwd_data->length) {
236	    *minor_status = 0;
237	    return GSS_S_BAD_BINDINGS;
238	}
239	fwd_data->data = malloc(fwd_data->length);
240	if (fwd_data->data == NULL) {
241	    *minor_status = ENOMEM;
242	    return GSS_S_FAILURE;
243	}
244	memcpy(fwd_data->data, p, fwd_data->length);
245    }
246
247    return GSS_S_COMPLETE;
248}
249