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
38 static OM_uint32
unwrap_des(OM_uint32 * minor_status,const gsskrb5_ctx context_handle,const gss_buffer_t input_message_buffer,gss_buffer_t output_message_buffer,int * conf_state,gss_qop_t * qop_state,krb5_keyblock * key)39 unwrap_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 size_t 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 if (input_message_buffer->length < token_len)
68 return GSS_S_BAD_MECH;
69 } else {
70 token_len = input_message_buffer->length;
71 }
72
73 p = input_message_buffer->value;
74 ret = _gsskrb5_verify_header (&p,
75 token_len,
76 "\x02\x01",
77 GSS_KRB5_MECHANISM);
78 if (ret)
79 return ret;
80
81 len = (p - (u_char *)input_message_buffer->value)
82 + 22 + 8;
83 if (input_message_buffer->length < len)
84 return GSS_S_BAD_MECH;
85
86 if (memcmp (p, "\x00\x00", 2) != 0)
87 return GSS_S_BAD_SIG;
88 p += 2;
89 if (memcmp (p, "\x00\x00", 2) == 0) {
90 cstate = 1;
91 } else if (memcmp (p, "\xFF\xFF", 2) == 0) {
92 cstate = 0;
93 } else
94 return GSS_S_BAD_MIC;
95 p += 2;
96 if(conf_state != NULL)
97 *conf_state = cstate;
98 if (memcmp (p, "\xff\xff", 2) != 0)
99 return GSS_S_DEFECTIVE_TOKEN;
100 p += 2;
101 p += 16;
102
103 len = p - (u_char *)input_message_buffer->value;
104
105 if(cstate) {
106 /* decrypt data */
107 memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
108 memset (&zero, 0, sizeof(zero));
109
110 for (i = 0; i < sizeof(deskey); ++i)
111 deskey[i] ^= 0xf0;
112
113
114 des_ctx = EVP_CIPHER_CTX_new();
115 if (des_ctx == NULL) {
116 memset (deskey, 0, sizeof(deskey));
117 *minor_status = ENOMEM;
118 return GSS_S_FAILURE;
119 }
120 EVP_CipherInit_ex(des_ctx, EVP_des_cbc(), NULL, deskey, zero, 0);
121 EVP_Cipher(des_ctx, p, p, input_message_buffer->length - len);
122 EVP_CIPHER_CTX_free(des_ctx);
123
124 memset (deskey, 0, sizeof(deskey));
125 }
126
127 if (IS_DCE_STYLE(context_handle)) {
128 padlength = 0;
129 } else {
130 /* check pad */
131 ret = _gssapi_verify_pad(input_message_buffer,
132 input_message_buffer->length - len - 8,
133 &padlength);
134 if (ret)
135 return ret;
136 }
137
138 md5 = EVP_MD_CTX_create();
139 EVP_DigestInit_ex(md5, EVP_md5(), NULL);
140 EVP_DigestUpdate(md5, p - 24, 8);
141 EVP_DigestUpdate(md5, p, input_message_buffer->length - len);
142 EVP_DigestFinal_ex(md5, hash, NULL);
143 EVP_MD_CTX_destroy(md5);
144
145 memset (&zero, 0, sizeof(zero));
146 memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
147 DES_set_key_unchecked (&deskey, &schedule);
148 DES_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
149 &schedule, &zero);
150 if (ct_memcmp (p - 8, hash, 8) != 0) {
151 memset (deskey, 0, sizeof(deskey));
152 memset (&schedule, 0, sizeof(schedule));
153 return GSS_S_BAD_MIC;
154 }
155
156 /* verify sequence number */
157
158 des_ctx = EVP_CIPHER_CTX_new();
159 if (des_ctx == NULL) {
160 memset (deskey, 0, sizeof(deskey));
161 memset (&schedule, 0, sizeof(schedule));
162 *minor_status = ENOMEM;
163 return GSS_S_FAILURE;
164 }
165
166 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
167
168 p -= 16;
169
170 EVP_CipherInit_ex(des_ctx, EVP_des_cbc(), NULL, key->keyvalue.data, hash, 0);
171 EVP_Cipher(des_ctx, p, p, 8);
172 EVP_CIPHER_CTX_free(des_ctx);
173
174 memset (deskey, 0, sizeof(deskey));
175 memset (&schedule, 0, sizeof(schedule));
176
177 seq = p;
178 _gsskrb5_decode_om_uint32(seq, &seq_number);
179
180 if (context_handle->more_flags & LOCAL)
181 cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4);
182 else
183 cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4);
184
185 if (cmp != 0) {
186 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
187 return GSS_S_BAD_MIC;
188 }
189
190 ret = _gssapi_msg_order_check(context_handle->order, seq_number);
191 if (ret) {
192 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
193 return ret;
194 }
195
196 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
197
198 /* copy out data */
199
200 output_message_buffer->length = input_message_buffer->length
201 - len - padlength - 8;
202 output_message_buffer->value = malloc(output_message_buffer->length);
203 if(output_message_buffer->length != 0 && output_message_buffer->value == NULL)
204 return GSS_S_FAILURE;
205 if (output_message_buffer->value != NULL)
206 memcpy (output_message_buffer->value,
207 p + 24,
208 output_message_buffer->length);
209 return GSS_S_COMPLETE;
210 }
211 #endif
212
213 static OM_uint32
unwrap_des3(OM_uint32 * minor_status,const gsskrb5_ctx context_handle,krb5_context context,const gss_buffer_t input_message_buffer,gss_buffer_t output_message_buffer,int * conf_state,gss_qop_t * qop_state,krb5_keyblock * key)214 unwrap_des3
215 (OM_uint32 * minor_status,
216 const gsskrb5_ctx context_handle,
217 krb5_context context,
218 const gss_buffer_t input_message_buffer,
219 gss_buffer_t output_message_buffer,
220 int * conf_state,
221 gss_qop_t * qop_state,
222 krb5_keyblock *key
223 )
224 {
225 u_char *p;
226 size_t len;
227 u_char *seq;
228 krb5_data seq_data;
229 u_char cksum[20];
230 uint32_t seq_number;
231 size_t padlength;
232 OM_uint32 ret;
233 int cstate;
234 krb5_crypto crypto;
235 Checksum csum;
236 int cmp;
237 int token_len;
238
239 if (IS_DCE_STYLE(context_handle)) {
240 token_len = 34 + 8 + 15; /* 57 */
241 if (input_message_buffer->length < token_len)
242 return GSS_S_BAD_MECH;
243 } else {
244 token_len = input_message_buffer->length;
245 }
246
247 p = input_message_buffer->value;
248 ret = _gsskrb5_verify_header (&p,
249 token_len,
250 "\x02\x01",
251 GSS_KRB5_MECHANISM);
252 if (ret)
253 return ret;
254
255 len = (p - (u_char *)input_message_buffer->value)
256 + 34 + 8;
257 if (input_message_buffer->length < len)
258 return GSS_S_BAD_MECH;
259
260 if (ct_memcmp (p, "\x04\x00", 2) != 0) /* HMAC SHA1 DES3_KD */
261 return GSS_S_BAD_SIG;
262 p += 2;
263 if (ct_memcmp (p, "\x02\x00", 2) == 0) {
264 cstate = 1;
265 } else if (ct_memcmp (p, "\xff\xff", 2) == 0) {
266 cstate = 0;
267 } else
268 return GSS_S_BAD_MIC;
269 p += 2;
270 if(conf_state != NULL)
271 *conf_state = cstate;
272 if (ct_memcmp (p, "\xff\xff", 2) != 0)
273 return GSS_S_DEFECTIVE_TOKEN;
274 p += 2;
275 p += 28;
276
277 len = p - (u_char *)input_message_buffer->value;
278
279 if(cstate) {
280 /* decrypt data */
281 krb5_data tmp;
282
283 ret = krb5_crypto_init(context, key,
284 ETYPE_DES3_CBC_NONE, &crypto);
285 if (ret) {
286 *minor_status = ret;
287 return GSS_S_FAILURE;
288 }
289 ret = krb5_decrypt(context, crypto, KRB5_KU_USAGE_SEAL,
290 p, input_message_buffer->length - len, &tmp);
291 krb5_crypto_destroy(context, crypto);
292 if (ret) {
293 *minor_status = ret;
294 return GSS_S_FAILURE;
295 }
296 assert (tmp.length == input_message_buffer->length - len);
297
298 memcpy (p, tmp.data, tmp.length);
299 krb5_data_free(&tmp);
300 }
301
302 if (IS_DCE_STYLE(context_handle)) {
303 padlength = 0;
304 } else {
305 /* check pad */
306 ret = _gssapi_verify_pad(input_message_buffer,
307 input_message_buffer->length - len - 8,
308 &padlength);
309 if (ret)
310 return ret;
311 }
312
313 /* verify sequence number */
314
315 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex);
316
317 p -= 28;
318
319 ret = krb5_crypto_init(context, key,
320 ETYPE_DES3_CBC_NONE, &crypto);
321 if (ret) {
322 *minor_status = ret;
323 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
324 return GSS_S_FAILURE;
325 }
326 {
327 DES_cblock ivec;
328
329 memcpy(&ivec, p + 8, 8);
330 ret = krb5_decrypt_ivec (context,
331 crypto,
332 KRB5_KU_USAGE_SEQ,
333 p, 8, &seq_data,
334 &ivec);
335 }
336 krb5_crypto_destroy (context, crypto);
337 if (ret) {
338 *minor_status = ret;
339 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
340 return GSS_S_FAILURE;
341 }
342 if (seq_data.length != 8) {
343 krb5_data_free (&seq_data);
344 *minor_status = 0;
345 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
346 return GSS_S_BAD_MIC;
347 }
348
349 seq = seq_data.data;
350 _gsskrb5_decode_om_uint32(seq, &seq_number);
351
352 if (context_handle->more_flags & LOCAL)
353 cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4);
354 else
355 cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4);
356
357 krb5_data_free (&seq_data);
358 if (cmp != 0) {
359 *minor_status = 0;
360 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
361 return GSS_S_BAD_MIC;
362 }
363
364 ret = _gssapi_msg_order_check(context_handle->order, seq_number);
365 if (ret) {
366 *minor_status = 0;
367 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
368 return ret;
369 }
370
371 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex);
372
373 /* verify checksum */
374
375 memcpy (cksum, p + 8, 20);
376
377 memcpy (p + 20, p - 8, 8);
378
379 csum.cksumtype = CKSUMTYPE_HMAC_SHA1_DES3;
380 csum.checksum.length = 20;
381 csum.checksum.data = cksum;
382
383 ret = krb5_crypto_init(context, key, 0, &crypto);
384 if (ret) {
385 *minor_status = ret;
386 return GSS_S_FAILURE;
387 }
388
389 ret = krb5_verify_checksum (context, crypto,
390 KRB5_KU_USAGE_SIGN,
391 p + 20,
392 input_message_buffer->length - len + 8,
393 &csum);
394 krb5_crypto_destroy (context, crypto);
395 if (ret) {
396 *minor_status = ret;
397 return GSS_S_FAILURE;
398 }
399
400 /* copy out data */
401
402 output_message_buffer->length = input_message_buffer->length
403 - len - padlength - 8;
404 output_message_buffer->value = malloc(output_message_buffer->length);
405 if(output_message_buffer->length != 0 && output_message_buffer->value == NULL)
406 return GSS_S_FAILURE;
407 if (output_message_buffer->value != NULL)
408 memcpy (output_message_buffer->value,
409 p + 36,
410 output_message_buffer->length);
411 return GSS_S_COMPLETE;
412 }
413
_gsskrb5_unwrap(OM_uint32 * minor_status,const gss_ctx_id_t context_handle,const gss_buffer_t input_message_buffer,gss_buffer_t output_message_buffer,int * conf_state,gss_qop_t * qop_state)414 OM_uint32 GSSAPI_CALLCONV _gsskrb5_unwrap
415 (OM_uint32 * minor_status,
416 const gss_ctx_id_t context_handle,
417 const gss_buffer_t input_message_buffer,
418 gss_buffer_t output_message_buffer,
419 int * conf_state,
420 gss_qop_t * qop_state
421 )
422 {
423 krb5_keyblock *key;
424 krb5_context context;
425 OM_uint32 ret;
426 krb5_keytype keytype;
427 gsskrb5_ctx ctx = (gsskrb5_ctx) context_handle;
428
429 output_message_buffer->value = NULL;
430 output_message_buffer->length = 0;
431 if (qop_state != NULL)
432 *qop_state = GSS_C_QOP_DEFAULT;
433
434 GSSAPI_KRB5_INIT (&context);
435
436 if (ctx->more_flags & IS_CFX)
437 return _gssapi_unwrap_cfx (minor_status, ctx, context,
438 input_message_buffer, output_message_buffer,
439 conf_state, qop_state);
440
441 HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
442 ret = _gsskrb5i_get_token_key(ctx, context, &key);
443 HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
444 if (ret) {
445 *minor_status = ret;
446 return GSS_S_FAILURE;
447 }
448 krb5_enctype_to_keytype (context, key->keytype, &keytype);
449
450 *minor_status = 0;
451
452 switch (keytype) {
453 case KEYTYPE_DES :
454 #ifdef HEIM_WEAK_CRYPTO
455 ret = unwrap_des (minor_status, ctx,
456 input_message_buffer, output_message_buffer,
457 conf_state, qop_state, key);
458 #else
459 ret = GSS_S_FAILURE;
460 #endif
461 break;
462 case KEYTYPE_DES3 :
463 ret = unwrap_des3 (minor_status, ctx, context,
464 input_message_buffer, output_message_buffer,
465 conf_state, qop_state, key);
466 break;
467 case KEYTYPE_ARCFOUR:
468 case KEYTYPE_ARCFOUR_56:
469 ret = _gssapi_unwrap_arcfour (minor_status, ctx, context,
470 input_message_buffer, output_message_buffer,
471 conf_state, qop_state, key);
472 break;
473 default :
474 abort();
475 break;
476 }
477 krb5_free_keyblock (context, key);
478 return ret;
479 }
480