source: vendor/current/source4/heimdal/lib/gssapi/krb5/unwrap.c@ 740

Last change on this file since 740 was 740, checked in by Silvan Scherrer, 12 years ago

Samba Server: update vendor to 3.6.0
File size: 12.2 KB
Line 
1/*
2 * Copyright (c) 1997 - 2004 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
39unwrap_des
40 (OM_uint32 * minor_status,
41 const gsskrb5_ctx context_handle,
42 const gss_buffer_t input_message_buffer,
43 gss_buffer_t output_message_buffer,
44 int * conf_state,
45 gss_qop_t * qop_state,
46 krb5_keyblock *key
47 )
48{
49 u_char *p, *seq;
50 size_t len;
51 EVP_MD_CTX *md5;
52 u_char hash[16];
53 EVP_CIPHER_CTX des_ctx;
54 DES_key_schedule schedule;
55 DES_cblock deskey;
56 DES_cblock zero;
57 int i;
58 uint32_t seq_number;
59 size_t padlength;
60 OM_uint32 ret;
61 int cstate;
62 int cmp;
63 int token_len;
64
65 if (IS_DCE_STYLE(context_handle)) {
66 token_len = 22 + 8 + 15; /* 45 */
67 } else {
68 token_len = input_message_buffer->length;
69 }
70
71 p = input_message_buffer->value;
72 ret = _gsskrb5_verify_header (&p,
73 token_len,
74 "\x02\x01",
75 GSS_KRB5_MECHANISM);
76 if (ret)
77 return ret;
78
79 if (memcmp (p, "\x00\x00", 2) != 0)
80 return GSS_S_BAD_SIG;
81 p += 2;
82 if (memcmp (p, "\x00\x00", 2) == 0) {
83 cstate = 1;
84 } else if (memcmp (p, "\xFF\xFF", 2) == 0) {
85 cstate = 0;
86 } else
87 return GSS_S_BAD_MIC;
88 p += 2;
89 if(conf_state != NULL)
90 *conf_state = cstate;
91 if (memcmp (p, "\xff\xff", 2) != 0)
92 return GSS_S_DEFECTIVE_TOKEN;
93 p += 2;
94 p += 16;
95
96 len = p - (u_char *)input_message_buffer->value;
97
98 if(cstate) {
99 /* decrypt data */
100 memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
101
102 for (i = 0; i < sizeof(deskey); ++i)
103 deskey[i] ^= 0xf0;
104
105
106 EVP_CIPHER_CTX_init(&des_ctx);
107 EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, deskey, zero, 0);
108 EVP_Cipher(&des_ctx, p, p, input_message_buffer->length - len);
109 EVP_CIPHER_CTX_cleanup(&des_ctx);
110
111 memset (&schedule, 0, sizeof(schedule));
112 }
113
114 if (IS_DCE_STYLE(context_handle)) {
115 padlength = 0;
116 } else {
117 /* check pad */
118 ret = _gssapi_verify_pad(input_message_buffer,
119 input_message_buffer->length - len,
120 &padlength);
121 if (ret)
122 return ret;
123 }
124
125 md5 = EVP_MD_CTX_create();
126 EVP_DigestInit_ex(md5, EVP_md5(), NULL);
127 EVP_DigestUpdate(md5, p - 24, 8);
128 EVP_DigestUpdate(md5, p, input_message_buffer->length - len);
129 EVP_DigestFinal_ex(md5, hash, NULL);
130 EVP_MD_CTX_destroy(md5);
131
132 memset (&zero, 0, sizeof(zero));
133 memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
134 DES_set_key_unchecked (&deskey, &schedule);
135 DES_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
136 &schedule, &zero);
137 if (ct_memcmp (p - 8, hash, 8) != 0)
138 return GSS_S_BAD_MIC;
139
140 /* verify sequence number */
141
142 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
143
144 p -= 16;
145
146 EVP_CIPHER_CTX_init(&des_ctx);
147 EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, key->keyvalue.data, hash, 0);
148 EVP_Cipher(&des_ctx, p, p, 8);
149 EVP_CIPHER_CTX_cleanup(&des_ctx);
150
151 memset (deskey, 0, sizeof(deskey));
152 memset (&schedule, 0, sizeof(schedule));
153
154 seq = p;
155 _gsskrb5_decode_om_uint32(seq, &seq_number);
156
157 if (context_handle->more_flags & LOCAL)
158 cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4);
159 else
160 cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4);
161
162 if (cmp != 0) {
163 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
164 return GSS_S_BAD_MIC;
165 }
166
167 ret = _gssapi_msg_order_check(context_handle->order, seq_number);
168 if (ret) {
169 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
170 return ret;
171 }
172
173 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
174
175 /* copy out data */
176
177 output_message_buffer->length = input_message_buffer->length
178 - len - padlength - 8;
179 output_message_buffer->value = malloc(output_message_buffer->length);
180 if(output_message_buffer->length != 0 && output_message_buffer->value == NULL)
181 return GSS_S_FAILURE;
182 memcpy (output_message_buffer->value,
183 p + 24,
184 output_message_buffer->length);
185 return GSS_S_COMPLETE;
186}
187#endif
188
189static OM_uint32
190unwrap_des3
191 (OM_uint32 * minor_status,
192 const gsskrb5_ctx context_handle,
193 krb5_context context,
194 const gss_buffer_t input_message_buffer,
195 gss_buffer_t output_message_buffer,
196 int * conf_state,
197 gss_qop_t * qop_state,
198 krb5_keyblock *key
199 )
200{
201 u_char *p;
202 size_t len;
203 u_char *seq;
204 krb5_data seq_data;
205 u_char cksum[20];
206 uint32_t seq_number;
207 size_t padlength;
208 OM_uint32 ret;
209 int cstate;
210 krb5_crypto crypto;
211 Checksum csum;
212 int cmp;
213 int token_len;
214
215 if (IS_DCE_STYLE(context_handle)) {
216 token_len = 34 + 8 + 15; /* 57 */
217 } else {
218 token_len = input_message_buffer->length;
219 }
220
221 p = input_message_buffer->value;
222 ret = _gsskrb5_verify_header (&p,
223 token_len,
224 "\x02\x01",
225 GSS_KRB5_MECHANISM);
226 if (ret)
227 return ret;
228
229 if (memcmp (p, "\x04\x00", 2) != 0) /* HMAC SHA1 DES3_KD */
230 return GSS_S_BAD_SIG;
231 p += 2;
232 if (ct_memcmp (p, "\x02\x00", 2) == 0) {
233 cstate = 1;
234 } else if (ct_memcmp (p, "\xff\xff", 2) == 0) {
235 cstate = 0;
236 } else
237 return GSS_S_BAD_MIC;
238 p += 2;
239 if(conf_state != NULL)
240 *conf_state = cstate;
241 if (ct_memcmp (p, "\xff\xff", 2) != 0)
242 return GSS_S_DEFECTIVE_TOKEN;
243 p += 2;
244 p += 28;
245
246 len = p - (u_char *)input_message_buffer->value;
247
248 if(cstate) {
249 /* decrypt data */
250 krb5_data tmp;
251
252 ret = krb5_crypto_init(context, key,
253 ETYPE_DES3_CBC_NONE, &crypto);
254 if (ret) {
255 *minor_status = ret;
256 return GSS_S_FAILURE;
257 }
258 ret = krb5_decrypt(context, crypto, KRB5_KU_USAGE_SEAL,
259 p, input_message_buffer->length - len, &tmp);
260 krb5_crypto_destroy(context, crypto);
261 if (ret) {
262 *minor_status = ret;
263 return GSS_S_FAILURE;
264 }
265 assert (tmp.length == input_message_buffer->length - len);
266
267 memcpy (p, tmp.data, tmp.length);
268 krb5_data_free(&tmp);
269 }
270
271 if (IS_DCE_STYLE(context_handle)) {
272 padlength = 0;
273 } else {
274 /* check pad */
275 ret = _gssapi_verify_pad(input_message_buffer,
276 input_message_buffer->length - len,
277 &padlength);
278 if (ret)
279 return ret;
280 }
281
282 /* verify sequence number */
283
284 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
285
286 p -= 28;
287
288 ret = krb5_crypto_init(context, key,
289 ETYPE_DES3_CBC_NONE, &crypto);
290 if (ret) {
291 *minor_status = ret;
292 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
293 return GSS_S_FAILURE;
294 }
295 {
296 DES_cblock ivec;
297
298 memcpy(&ivec, p + 8, 8);
299 ret = krb5_decrypt_ivec (context,
300 crypto,
301 KRB5_KU_USAGE_SEQ,
302 p, 8, &seq_data,
303 &ivec);
304 }
305 krb5_crypto_destroy (context, crypto);
306 if (ret) {
307 *minor_status = ret;
308 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
309 return GSS_S_FAILURE;
310 }
311 if (seq_data.length != 8) {
312 krb5_data_free (&seq_data);
313 *minor_status = 0;
314 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
315 return GSS_S_BAD_MIC;
316 }
317
318 seq = seq_data.data;
319 _gsskrb5_decode_om_uint32(seq, &seq_number);
320
321 if (context_handle->more_flags & LOCAL)
322 cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4);
323 else
324 cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4);
325
326 krb5_data_free (&seq_data);
327 if (cmp != 0) {
328 *minor_status = 0;
329 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
330 return GSS_S_BAD_MIC;
331 }
332
333 ret = _gssapi_msg_order_check(context_handle->order, seq_number);
334 if (ret) {
335 *minor_status = 0;
336 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
337 return ret;
338 }
339
340 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
341
342 /* verify checksum */
343
344 memcpy (cksum, p + 8, 20);
345
346 memcpy (p + 20, p - 8, 8);
347
348 csum.cksumtype = CKSUMTYPE_HMAC_SHA1_DES3;
349 csum.checksum.length = 20;
350 csum.checksum.data = cksum;
351
352 ret = krb5_crypto_init(context, key, 0, &crypto);
353 if (ret) {
354 *minor_status = ret;
355 return GSS_S_FAILURE;
356 }
357
358 ret = krb5_verify_checksum (context, crypto,
359 KRB5_KU_USAGE_SIGN,
360 p + 20,
361 input_message_buffer->length - len + 8,
362 &csum);
363 krb5_crypto_destroy (context, crypto);
364 if (ret) {
365 *minor_status = ret;
366 return GSS_S_FAILURE;
367 }
368
369 /* copy out data */
370
371 output_message_buffer->length = input_message_buffer->length
372 - len - padlength - 8;
373 output_message_buffer->value = malloc(output_message_buffer->length);
374 if(output_message_buffer->length != 0 && output_message_buffer->value == NULL)
375 return GSS_S_FAILURE;
376 memcpy (output_message_buffer->value,
377 p + 36,
378 output_message_buffer->length);
379 return GSS_S_COMPLETE;
380}
381
382OM_uint32 GSSAPI_CALLCONV _gsskrb5_unwrap
383 (OM_uint32 * minor_status,
384 const gss_ctx_id_t context_handle,
385 const gss_buffer_t input_message_buffer,
386 gss_buffer_t output_message_buffer,
387 int * conf_state,
388 gss_qop_t * qop_state
389 )
390{
391 krb5_keyblock *key;
392 krb5_context context;
393 OM_uint32 ret;
394 krb5_keytype keytype;
395 gsskrb5_ctx ctx = (gsskrb5_ctx) context_handle;
396
397 output_message_buffer->value = NULL;
398 output_message_buffer->length = 0;
399 if (qop_state != NULL)
400 *qop_state = GSS_C_QOP_DEFAULT;
401
402 GSSAPI_KRB5_INIT (&context);
403
404 if (ctx->more_flags & IS_CFX)
405 return _gssapi_unwrap_cfx (minor_status, ctx, context,
406 input_message_buffer, output_message_buffer,
407 conf_state, qop_state);
408
409 HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
410 ret = _gsskrb5i_get_token_key(ctx, context, &key);
411 HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
412 if (ret) {
413 *minor_status = ret;
414 return GSS_S_FAILURE;
415 }
416 krb5_enctype_to_keytype (context, key->keytype, &keytype);
417
418 *minor_status = 0;
419
420 switch (keytype) {
421 case KEYTYPE_DES :
422#ifdef HEIM_WEAK_CRYPTO
423 ret = unwrap_des (minor_status, ctx,
424 input_message_buffer, output_message_buffer,
425 conf_state, qop_state, key);
426#else
427 ret = GSS_S_FAILURE;
428#endif
429 break;
430 case KEYTYPE_DES3 :
431 ret = unwrap_des3 (minor_status, ctx, context,
432 input_message_buffer, output_message_buffer,
433 conf_state, qop_state, key);
434 break;
435 case KEYTYPE_ARCFOUR:
436 case KEYTYPE_ARCFOUR_56:
437 ret = _gssapi_unwrap_arcfour (minor_status, ctx, context,
438 input_message_buffer, output_message_buffer,
439 conf_state, qop_state, key);
440 break;
441 default :
442 abort();
443 break;
444 }
445 krb5_free_keyblock (context, key);
446 return ret;
447}
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