source: heimdal/trunk/lib/gssapi/krb5/verify_mic.c

Last change on this file was 1, checked in by Paul Smedley, 10 years ago

Initial commit of Heimdal 1.5.3
File size: 9.5 KB
Line 
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#ifdef HEIM_WEAK_CRYPTO
37
38static OM_uint32
39verify_mic_des
40 (OM_uint32 * minor_status,
41 const gsskrb5_ctx context_handle,
42 krb5_context context,
43 const gss_buffer_t message_buffer,
44 const gss_buffer_t token_buffer,
45 gss_qop_t * qop_state,
46 krb5_keyblock *key,
47 const char *type
48 )
49{
50 u_char *p;
51 EVP_MD_CTX *md5;
52 u_char hash[16], *seq;
53 DES_key_schedule schedule;
54 EVP_CIPHER_CTX des_ctx;
55 DES_cblock zero;
56 DES_cblock deskey;
57 uint32_t seq_number;
58 OM_uint32 ret;
59 int cmp;
60
61 p = token_buffer->value;
62 ret = _gsskrb5_verify_header (&p,
63 token_buffer->length,
64 type,
65 GSS_KRB5_MECHANISM);
66 if (ret)
67 return ret;
68
69 if (memcmp(p, "\x00\x00", 2) != 0)
70 return GSS_S_BAD_SIG;
71 p += 2;
72 if (memcmp (p, "\xff\xff\xff\xff", 4) != 0)
73 return GSS_S_BAD_MIC;
74 p += 4;
75 p += 16;
76
77 /* verify checksum */
78 md5 = EVP_MD_CTX_create();
79 EVP_DigestInit_ex(md5, EVP_md5(), NULL);
80 EVP_DigestUpdate(md5, p - 24, 8);
81 EVP_DigestUpdate(md5, message_buffer->value, message_buffer->length);
82 EVP_DigestFinal_ex(md5, hash, NULL);
83 EVP_MD_CTX_destroy(md5);
84
85 memset (&zero, 0, sizeof(zero));
86 memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
87
88 DES_set_key_unchecked (&deskey, &schedule);
89 DES_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
90 &schedule, &zero);
91 if (ct_memcmp (p - 8, hash, 8) != 0) {
92 memset (deskey, 0, sizeof(deskey));
93 memset (&schedule, 0, sizeof(schedule));
94 return GSS_S_BAD_MIC;
95 }
96
97 /* verify sequence number */
98
99 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
100
101 p -= 16;
102
103 EVP_CIPHER_CTX_init(&des_ctx);
104 EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, key->keyvalue.data, hash, 0);
105 EVP_Cipher(&des_ctx, p, p, 8);
106 EVP_CIPHER_CTX_cleanup(&des_ctx);
107
108 memset (deskey, 0, sizeof(deskey));
109 memset (&schedule, 0, sizeof(schedule));
110
111 seq = p;
112 _gsskrb5_decode_om_uint32(seq, &seq_number);
113
114 if (context_handle->more_flags & LOCAL)
115 cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4);
116 else
117 cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4);
118
119 if (cmp != 0) {
120 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
121 return GSS_S_BAD_MIC;
122 }
123
124 ret = _gssapi_msg_order_check(context_handle->order, seq_number);
125 if (ret) {
126 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
127 return ret;
128 }
129
130 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
131
132 return GSS_S_COMPLETE;
133}
134#endif
135
136static OM_uint32
137verify_mic_des3
138 (OM_uint32 * minor_status,
139 const gsskrb5_ctx context_handle,
140 krb5_context context,
141 const gss_buffer_t message_buffer,
142 const gss_buffer_t token_buffer,
143 gss_qop_t * qop_state,
144 krb5_keyblock *key,
145 const char *type
146 )
147{
148 u_char *p;
149 u_char *seq;
150 uint32_t seq_number;
151 OM_uint32 ret;
152 krb5_crypto crypto;
153 krb5_data seq_data;
154 int cmp, docompat;
155 Checksum csum;
156 char *tmp;
157 char ivec[8];
158
159 p = token_buffer->value;
160 ret = _gsskrb5_verify_header (&p,
161 token_buffer->length,
162 type,
163 GSS_KRB5_MECHANISM);
164 if (ret)
165 return ret;
166
167 if (memcmp(p, "\x04\x00", 2) != 0) /* SGN_ALG = HMAC SHA1 DES3-KD */
168 return GSS_S_BAD_SIG;
169 p += 2;
170 if (memcmp (p, "\xff\xff\xff\xff", 4) != 0)
171 return GSS_S_BAD_MIC;
172 p += 4;
173
174 ret = krb5_crypto_init(context, key,
175 ETYPE_DES3_CBC_NONE, &crypto);
176 if (ret){
177 *minor_status = ret;
178 return GSS_S_FAILURE;
179 }
180
181 /* verify sequence number */
182 docompat = 0;
183retry:
184 if (docompat)
185 memset(ivec, 0, 8);
186 else
187 memcpy(ivec, p + 8, 8);
188
189 ret = krb5_decrypt_ivec (context,
190 crypto,
191 KRB5_KU_USAGE_SEQ,
192 p, 8, &seq_data, ivec);
193 if (ret) {
194 if (docompat++) {
195 krb5_crypto_destroy (context, crypto);
196 *minor_status = ret;
197 return GSS_S_FAILURE;
198 } else
199 goto retry;
200 }
201
202 if (seq_data.length != 8) {
203 krb5_data_free (&seq_data);
204 if (docompat++) {
205 krb5_crypto_destroy (context, crypto);
206 return GSS_S_BAD_MIC;
207 } else
208 goto retry;
209 }
210
211 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
212
213 seq = seq_data.data;
214 _gsskrb5_decode_om_uint32(seq, &seq_number);
215
216 if (context_handle->more_flags & LOCAL)
217 cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4);
218 else
219 cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4);
220
221 krb5_data_free (&seq_data);
222 if (cmp != 0) {
223 krb5_crypto_destroy (context, crypto);
224 *minor_status = 0;
225 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
226 return GSS_S_BAD_MIC;
227 }
228
229 ret = _gssapi_msg_order_check(context_handle->order, seq_number);
230 if (ret) {
231 krb5_crypto_destroy (context, crypto);
232 *minor_status = 0;
233 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
234 return ret;
235 }
236
237 /* verify checksum */
238
239 tmp = malloc (message_buffer->length + 8);
240 if (tmp == NULL) {
241 krb5_crypto_destroy (context, crypto);
242 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
243 *minor_status = ENOMEM;
244 return GSS_S_FAILURE;
245 }
246
247 memcpy (tmp, p - 8, 8);
248 memcpy (tmp + 8, message_buffer->value, message_buffer->length);
249
250 csum.cksumtype = CKSUMTYPE_HMAC_SHA1_DES3;
251 csum.checksum.length = 20;
252 csum.checksum.data = p + 8;
253
254 krb5_crypto_destroy (context, crypto);
255 ret = krb5_crypto_init(context, key,
256 ETYPE_DES3_CBC_SHA1, &crypto);
257 if (ret){
258 *minor_status = ret;
259 return GSS_S_FAILURE;
260 }
261
262 ret = krb5_verify_checksum (context, crypto,
263 KRB5_KU_USAGE_SIGN,
264 tmp, message_buffer->length + 8,
265 &csum);
266 free (tmp);
267 if (ret) {
268 krb5_crypto_destroy (context, crypto);
269 *minor_status = ret;
270 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
271 return GSS_S_BAD_MIC;
272 }
273 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
274
275 krb5_crypto_destroy (context, crypto);
276 return GSS_S_COMPLETE;
277}
278
279OM_uint32
280_gsskrb5_verify_mic_internal
281 (OM_uint32 * minor_status,
282 const gsskrb5_ctx ctx,
283 krb5_context context,
284 const gss_buffer_t message_buffer,
285 const gss_buffer_t token_buffer,
286 gss_qop_t * qop_state,
287 const char * type
288 )
289{
290 krb5_keyblock *key;
291 OM_uint32 ret;
292 krb5_keytype keytype;
293
294 if (ctx->more_flags & IS_CFX)
295 return _gssapi_verify_mic_cfx (minor_status, ctx,
296 context, message_buffer, token_buffer,
297 qop_state);
298
299 HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
300 ret = _gsskrb5i_get_token_key(ctx, context, &key);
301 HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
302 if (ret) {
303 *minor_status = ret;
304 return GSS_S_FAILURE;
305 }
306 *minor_status = 0;
307 krb5_enctype_to_keytype (context, key->keytype, &keytype);
308 switch (keytype) {
309 case KEYTYPE_DES :
310#ifdef HEIM_WEAK_CRYPTO
311 ret = verify_mic_des (minor_status, ctx, context,
312 message_buffer, token_buffer, qop_state, key,
313 type);
314#else
315 ret = GSS_S_FAILURE;
316#endif
317 break;
318 case KEYTYPE_DES3 :
319 ret = verify_mic_des3 (minor_status, ctx, context,
320 message_buffer, token_buffer, qop_state, key,
321 type);
322 break;
323 case KEYTYPE_ARCFOUR :
324 case KEYTYPE_ARCFOUR_56 :
325 ret = _gssapi_verify_mic_arcfour (minor_status, ctx,
326 context,
327 message_buffer, token_buffer,
328 qop_state, key, type);
329 break;
330 default :
331 abort();
332 }
333 krb5_free_keyblock (context, key);
334
335 return ret;
336}
337
338OM_uint32 GSSAPI_CALLCONV
339_gsskrb5_verify_mic
340 (OM_uint32 * minor_status,
341 const gss_ctx_id_t context_handle,
342 const gss_buffer_t message_buffer,
343 const gss_buffer_t token_buffer,
344 gss_qop_t * qop_state
345 )
346{
347 krb5_context context;
348 OM_uint32 ret;
349
350 GSSAPI_KRB5_INIT (&context);
351
352 if (qop_state != NULL)
353 *qop_state = GSS_C_QOP_DEFAULT;
354
355 ret = _gsskrb5_verify_mic_internal(minor_status,
356 (gsskrb5_ctx)context_handle,
357 context,
358 message_buffer, token_buffer,
359 qop_state, (void *)(intptr_t)"\x01\x01");
360
361 return ret;
362}
Note: See TracBrowser for help on using the repository browser.