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: verify_mic.c 19031 2006-11-13 18:02:57Z lha $");
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	    char *type
48	    )
49{
50  u_char *p;
51  MD5_CTX md5;
52  u_char hash[16], *seq;
53  DES_key_schedule schedule;
54  DES_cblock zero;
55  DES_cblock deskey;
56  uint32_t seq_number;
57  OM_uint32 ret;
58  int cmp;
59
60  p = token_buffer->value;
61  ret = _gsskrb5_verify_header (&p,
62				   token_buffer->length,
63				   type,
64				   GSS_KRB5_MECHANISM);
65  if (ret)
66      return ret;
67
68  if (memcmp(p, "\x00\x00", 2) != 0)
69      return GSS_S_BAD_SIG;
70  p += 2;
71  if (memcmp (p, "\xff\xff\xff\xff", 4) != 0)
72    return GSS_S_BAD_MIC;
73  p += 4;
74  p += 16;
75
76  /* verify checksum */
77  MD5_Init (&md5);
78  MD5_Update (&md5, p - 24, 8);
79  MD5_Update (&md5, message_buffer->value,
80	     message_buffer->length);
81  MD5_Final (hash, &md5);
82
83  memset (&zero, 0, sizeof(zero));
84  memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
85
86  DES_set_key (&deskey, &schedule);
87  DES_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
88		 &schedule, &zero);
89  if (memcmp (p - 8, hash, 8) != 0) {
90    memset (deskey, 0, sizeof(deskey));
91    memset (&schedule, 0, sizeof(schedule));
92    return GSS_S_BAD_MIC;
93  }
94
95  /* verify sequence number */
96
97  HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
98
99  p -= 16;
100  DES_set_key (&deskey, &schedule);
101  DES_cbc_encrypt ((void *)p, (void *)p, 8,
102		   &schedule, (DES_cblock *)hash, DES_DECRYPT);
103
104  memset (deskey, 0, sizeof(deskey));
105  memset (&schedule, 0, sizeof(schedule));
106
107  seq = p;
108  _gsskrb5_decode_om_uint32(seq, &seq_number);
109
110  if (context_handle->more_flags & LOCAL)
111      cmp = memcmp(&seq[4], "\xff\xff\xff\xff", 4);
112  else
113      cmp = memcmp(&seq[4], "\x00\x00\x00\x00", 4);
114
115  if (cmp != 0) {
116    HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
117    return GSS_S_BAD_MIC;
118  }
119
120  ret = _gssapi_msg_order_check(context_handle->order, seq_number);
121  if (ret) {
122      HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
123      return ret;
124  }
125
126  HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
127
128  return GSS_S_COMPLETE;
129}
130
131static OM_uint32
132verify_mic_des3
133           (OM_uint32 * minor_status,
134            const gsskrb5_ctx context_handle,
135	    krb5_context context,
136            const gss_buffer_t message_buffer,
137            const gss_buffer_t token_buffer,
138            gss_qop_t * qop_state,
139	    krb5_keyblock *key,
140	    char *type
141	    )
142{
143  u_char *p;
144  u_char *seq;
145  uint32_t seq_number;
146  OM_uint32 ret;
147  krb5_crypto crypto;
148  krb5_data seq_data;
149  int cmp, docompat;
150  Checksum csum;
151  char *tmp;
152  char ivec[8];
153
154  p = token_buffer->value;
155  ret = _gsskrb5_verify_header (&p,
156				   token_buffer->length,
157				   type,
158				   GSS_KRB5_MECHANISM);
159  if (ret)
160      return ret;
161
162  if (memcmp(p, "\x04\x00", 2) != 0) /* SGN_ALG = HMAC SHA1 DES3-KD */
163      return GSS_S_BAD_SIG;
164  p += 2;
165  if (memcmp (p, "\xff\xff\xff\xff", 4) != 0)
166    return GSS_S_BAD_MIC;
167  p += 4;
168
169  ret = krb5_crypto_init(context, key,
170			 ETYPE_DES3_CBC_NONE, &crypto);
171  if (ret){
172      *minor_status = ret;
173      return GSS_S_FAILURE;
174  }
175
176  /* verify sequence number */
177  docompat = 0;
178retry:
179  if (docompat)
180      memset(ivec, 0, 8);
181  else
182      memcpy(ivec, p + 8, 8);
183
184  ret = krb5_decrypt_ivec (context,
185			   crypto,
186			   KRB5_KU_USAGE_SEQ,
187			   p, 8, &seq_data, ivec);
188  if (ret) {
189      if (docompat++) {
190	  krb5_crypto_destroy (context, crypto);
191	  *minor_status = ret;
192	  return GSS_S_FAILURE;
193      } else
194	  goto retry;
195  }
196
197  if (seq_data.length != 8) {
198      krb5_data_free (&seq_data);
199      if (docompat++) {
200	  krb5_crypto_destroy (context, crypto);
201	  return GSS_S_BAD_MIC;
202      } else
203	  goto retry;
204  }
205
206  HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
207
208  seq = seq_data.data;
209  _gsskrb5_decode_om_uint32(seq, &seq_number);
210
211  if (context_handle->more_flags & LOCAL)
212      cmp = memcmp(&seq[4], "\xff\xff\xff\xff", 4);
213  else
214      cmp = memcmp(&seq[4], "\x00\x00\x00\x00", 4);
215
216  krb5_data_free (&seq_data);
217  if (cmp != 0) {
218      krb5_crypto_destroy (context, crypto);
219      *minor_status = 0;
220      HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
221      return GSS_S_BAD_MIC;
222  }
223
224  ret = _gssapi_msg_order_check(context_handle->order, seq_number);
225  if (ret) {
226      krb5_crypto_destroy (context, crypto);
227      *minor_status = 0;
228      HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
229      return ret;
230  }
231
232  /* verify checksum */
233
234  tmp = malloc (message_buffer->length + 8);
235  if (tmp == NULL) {
236      krb5_crypto_destroy (context, crypto);
237      HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
238      *minor_status = ENOMEM;
239      return GSS_S_FAILURE;
240  }
241
242  memcpy (tmp, p - 8, 8);
243  memcpy (tmp + 8, message_buffer->value, message_buffer->length);
244
245  csum.cksumtype = CKSUMTYPE_HMAC_SHA1_DES3;
246  csum.checksum.length = 20;
247  csum.checksum.data   = p + 8;
248
249  ret = krb5_verify_checksum (context, crypto,
250			      KRB5_KU_USAGE_SIGN,
251			      tmp, message_buffer->length + 8,
252			      &csum);
253  free (tmp);
254  if (ret) {
255      krb5_crypto_destroy (context, crypto);
256      *minor_status = ret;
257      HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
258      return GSS_S_BAD_MIC;
259  }
260  HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
261
262  krb5_crypto_destroy (context, crypto);
263  return GSS_S_COMPLETE;
264}
265
266OM_uint32
267_gsskrb5_verify_mic_internal
268           (OM_uint32 * minor_status,
269            const gsskrb5_ctx context_handle,
270	    krb5_context context,
271            const gss_buffer_t message_buffer,
272            const gss_buffer_t token_buffer,
273            gss_qop_t * qop_state,
274	    char * type
275	    )
276{
277    krb5_keyblock *key;
278    OM_uint32 ret;
279    krb5_keytype keytype;
280
281    HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
282    ret = _gsskrb5i_get_token_key(context_handle, context, &key);
283    HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
284    if (ret) {
285	*minor_status = ret;
286	return GSS_S_FAILURE;
287    }
288    *minor_status = 0;
289    krb5_enctype_to_keytype (context, key->keytype, &keytype);
290    switch (keytype) {
291    case KEYTYPE_DES :
292	ret = verify_mic_des (minor_status, context_handle, context,
293			      message_buffer, token_buffer, qop_state, key,
294			      type);
295	break;
296    case KEYTYPE_DES3 :
297	ret = verify_mic_des3 (minor_status, context_handle, context,
298			       message_buffer, token_buffer, qop_state, key,
299			       type);
300	break;
301    case KEYTYPE_ARCFOUR :
302    case KEYTYPE_ARCFOUR_56 :
303	ret = _gssapi_verify_mic_arcfour (minor_status, context_handle,
304					  context,
305					  message_buffer, token_buffer,
306					  qop_state, key, type);
307	break;
308    default :
309	ret = _gssapi_verify_mic_cfx (minor_status, context_handle,
310				      context,
311				      message_buffer, token_buffer, qop_state,
312				      key);
313	break;
314    }
315    krb5_free_keyblock (context, key);
316
317    return ret;
318}
319
320OM_uint32
321_gsskrb5_verify_mic
322           (OM_uint32 * minor_status,
323            const gss_ctx_id_t context_handle,
324            const gss_buffer_t message_buffer,
325            const gss_buffer_t token_buffer,
326            gss_qop_t * qop_state
327	    )
328{
329    krb5_context context;
330    OM_uint32 ret;
331
332    GSSAPI_KRB5_INIT (&context);
333
334    if (qop_state != NULL)
335	*qop_state = GSS_C_QOP_DEFAULT;
336
337    ret = _gsskrb5_verify_mic_internal(minor_status,
338				       (gsskrb5_ctx)context_handle,
339				       context,
340				       message_buffer, token_buffer,
341				       qop_state, "\x01\x01");
342
343    return ret;
344}
345