1 /*
2 * Copyright (c) 1997 - 2003 Kungliga Tekniska Högskolan
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 "gsskrb5_locl.h"
35
36 krb5_error_code
_gsskrb5_encode_om_uint32(OM_uint32 n,u_char * p)37 _gsskrb5_encode_om_uint32(OM_uint32 n, u_char *p)
38 {
39 p[0] = (n >> 0) & 0xFF;
40 p[1] = (n >> 8) & 0xFF;
41 p[2] = (n >> 16) & 0xFF;
42 p[3] = (n >> 24) & 0xFF;
43 return 0;
44 }
45
46 krb5_error_code
_gsskrb5_encode_be_om_uint32(OM_uint32 n,u_char * p)47 _gsskrb5_encode_be_om_uint32(OM_uint32 n, u_char *p)
48 {
49 p[0] = (n >> 24) & 0xFF;
50 p[1] = (n >> 16) & 0xFF;
51 p[2] = (n >> 8) & 0xFF;
52 p[3] = (n >> 0) & 0xFF;
53 return 0;
54 }
55
56 krb5_error_code
_gsskrb5_decode_om_uint32(const void * ptr,OM_uint32 * n)57 _gsskrb5_decode_om_uint32(const void *ptr, OM_uint32 *n)
58 {
59 const u_char *p = ptr;
60 *n = (p[0] << 0) | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
61 return 0;
62 }
63
64 krb5_error_code
_gsskrb5_decode_be_om_uint32(const void * ptr,OM_uint32 * n)65 _gsskrb5_decode_be_om_uint32(const void *ptr, OM_uint32 *n)
66 {
67 const u_char *p = ptr;
68 *n = (p[0] <<24) | (p[1] << 16) | (p[2] << 8) | (p[3] << 0);
69 return 0;
70 }
71
72 static krb5_error_code
hash_input_chan_bindings(const gss_channel_bindings_t b,u_char * p)73 hash_input_chan_bindings (const gss_channel_bindings_t b,
74 u_char *p)
75 {
76 u_char num[4];
77 EVP_MD_CTX *ctx;
78
79 ctx = EVP_MD_CTX_create();
80 EVP_DigestInit_ex(ctx, EVP_md5(), NULL);
81
82 _gsskrb5_encode_om_uint32 (b->initiator_addrtype, num);
83 EVP_DigestUpdate(ctx, num, sizeof(num));
84 _gsskrb5_encode_om_uint32 (b->initiator_address.length, num);
85 EVP_DigestUpdate(ctx, num, sizeof(num));
86 if (b->initiator_address.length)
87 EVP_DigestUpdate(ctx,
88 b->initiator_address.value,
89 b->initiator_address.length);
90 _gsskrb5_encode_om_uint32 (b->acceptor_addrtype, num);
91 EVP_DigestUpdate(ctx, num, sizeof(num));
92 _gsskrb5_encode_om_uint32 (b->acceptor_address.length, num);
93 EVP_DigestUpdate(ctx, num, sizeof(num));
94 if (b->acceptor_address.length)
95 EVP_DigestUpdate(ctx,
96 b->acceptor_address.value,
97 b->acceptor_address.length);
98 _gsskrb5_encode_om_uint32 (b->application_data.length, num);
99 EVP_DigestUpdate(ctx, num, sizeof(num));
100 if (b->application_data.length)
101 EVP_DigestUpdate(ctx,
102 b->application_data.value,
103 b->application_data.length);
104 EVP_DigestFinal_ex(ctx, p, NULL);
105 EVP_MD_CTX_destroy(ctx);
106
107 return 0;
108 }
109
110 /*
111 * create a checksum over the chanel bindings in
112 * `input_chan_bindings', `flags' and `fwd_data' and return it in
113 * `result'
114 */
115
116 OM_uint32
_gsskrb5_create_8003_checksum(OM_uint32 * minor_status,const gss_channel_bindings_t input_chan_bindings,OM_uint32 flags,const krb5_data * fwd_data,Checksum * result)117 _gsskrb5_create_8003_checksum (
118 OM_uint32 *minor_status,
119 const gss_channel_bindings_t input_chan_bindings,
120 OM_uint32 flags,
121 const krb5_data *fwd_data,
122 Checksum *result)
123 {
124 u_char *p;
125
126 /*
127 * see rfc1964 (section 1.1.1 (Initial Token), and the checksum value
128 * field's format) */
129 result->cksumtype = CKSUMTYPE_GSSAPI;
130 if (fwd_data->length > 0 && (flags & GSS_C_DELEG_FLAG))
131 result->checksum.length = 24 + 4 + fwd_data->length;
132 else
133 result->checksum.length = 24;
134 result->checksum.data = malloc (result->checksum.length);
135 if (result->checksum.data == NULL) {
136 *minor_status = ENOMEM;
137 return GSS_S_FAILURE;
138 }
139
140 p = result->checksum.data;
141 _gsskrb5_encode_om_uint32 (16, p);
142 p += 4;
143 if (input_chan_bindings == GSS_C_NO_CHANNEL_BINDINGS) {
144 memset (p, 0, 16);
145 } else {
146 hash_input_chan_bindings (input_chan_bindings, p);
147 }
148 p += 16;
149 _gsskrb5_encode_om_uint32 (flags, p);
150 p += 4;
151
152 if (fwd_data->length > 0 && (flags & GSS_C_DELEG_FLAG)) {
153
154 *p++ = (1 >> 0) & 0xFF; /* DlgOpt */ /* == 1 */
155 *p++ = (1 >> 8) & 0xFF; /* DlgOpt */ /* == 0 */
156 *p++ = (fwd_data->length >> 0) & 0xFF; /* Dlgth */
157 *p++ = (fwd_data->length >> 8) & 0xFF; /* Dlgth */
158 memcpy(p, (unsigned char *) fwd_data->data, fwd_data->length);
159
160 p += fwd_data->length;
161 }
162
163 return GSS_S_COMPLETE;
164 }
165
166 /*
167 * verify the checksum in `cksum' over `input_chan_bindings'
168 * returning `flags' and `fwd_data'
169 */
170
171 OM_uint32
_gsskrb5_verify_8003_checksum(OM_uint32 * minor_status,const gss_channel_bindings_t input_chan_bindings,const Checksum * cksum,OM_uint32 * flags,krb5_data * fwd_data)172 _gsskrb5_verify_8003_checksum(
173 OM_uint32 *minor_status,
174 const gss_channel_bindings_t input_chan_bindings,
175 const Checksum *cksum,
176 OM_uint32 *flags,
177 krb5_data *fwd_data)
178 {
179 unsigned char hash[16];
180 unsigned char *p;
181 OM_uint32 length;
182 int DlgOpt;
183 static unsigned char zeros[16];
184
185 /* XXX should handle checksums > 24 bytes */
186 if(cksum->cksumtype != CKSUMTYPE_GSSAPI || cksum->checksum.length < 24) {
187 *minor_status = 0;
188 return GSS_S_BAD_BINDINGS;
189 }
190
191 p = cksum->checksum.data;
192 _gsskrb5_decode_om_uint32(p, &length);
193 if(length != sizeof(hash)) {
194 *minor_status = 0;
195 return GSS_S_BAD_BINDINGS;
196 }
197
198 p += 4;
199
200 if (input_chan_bindings != GSS_C_NO_CHANNEL_BINDINGS
201 && memcmp(p, zeros, sizeof(zeros)) != 0) {
202 if(hash_input_chan_bindings(input_chan_bindings, hash) != 0) {
203 *minor_status = 0;
204 return GSS_S_BAD_BINDINGS;
205 }
206 if(ct_memcmp(hash, p, sizeof(hash)) != 0) {
207 *minor_status = 0;
208 return GSS_S_BAD_BINDINGS;
209 }
210 }
211
212 p += sizeof(hash);
213
214 _gsskrb5_decode_om_uint32(p, flags);
215 p += 4;
216
217 if (cksum->checksum.length > 24 && (*flags & GSS_C_DELEG_FLAG)) {
218 if(cksum->checksum.length < 28) {
219 *minor_status = 0;
220 return GSS_S_BAD_BINDINGS;
221 }
222
223 DlgOpt = (p[0] << 0) | (p[1] << 8);
224 p += 2;
225 if (DlgOpt != 1) {
226 *minor_status = 0;
227 return GSS_S_BAD_BINDINGS;
228 }
229
230 fwd_data->length = (p[0] << 0) | (p[1] << 8);
231 p += 2;
232 if(cksum->checksum.length < 28 + fwd_data->length) {
233 *minor_status = 0;
234 return GSS_S_BAD_BINDINGS;
235 }
236 fwd_data->data = malloc(fwd_data->length);
237 if (fwd_data->data == NULL) {
238 *minor_status = ENOMEM;
239 return GSS_S_FAILURE;
240 }
241 memcpy(fwd_data->data, p, fwd_data->length);
242 }
243
244 return GSS_S_COMPLETE;
245 }
246