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 /*
37 * Return initiator subkey, or if that doesn't exists, the subkey.
38 */
39
40 krb5_error_code
_gsskrb5i_get_initiator_subkey(const gsskrb5_ctx ctx,krb5_context context,krb5_keyblock ** key)41 _gsskrb5i_get_initiator_subkey(const gsskrb5_ctx ctx,
42 krb5_context context,
43 krb5_keyblock **key)
44 {
45 krb5_error_code ret;
46 *key = NULL;
47
48 if (ctx->more_flags & LOCAL) {
49 ret = krb5_auth_con_getlocalsubkey(context,
50 ctx->auth_context,
51 key);
52 } else {
53 ret = krb5_auth_con_getremotesubkey(context,
54 ctx->auth_context,
55 key);
56 }
57 if (ret == 0 && *key == NULL)
58 ret = krb5_auth_con_getkey(context,
59 ctx->auth_context,
60 key);
61 if (ret == 0 && *key == NULL) {
62 krb5_set_error_message(context, 0, "No initiator subkey available");
63 return GSS_KRB5_S_KG_NO_SUBKEY;
64 }
65 return ret;
66 }
67
68 krb5_error_code
_gsskrb5i_get_acceptor_subkey(const gsskrb5_ctx ctx,krb5_context context,krb5_keyblock ** key)69 _gsskrb5i_get_acceptor_subkey(const gsskrb5_ctx ctx,
70 krb5_context context,
71 krb5_keyblock **key)
72 {
73 krb5_error_code ret;
74 *key = NULL;
75
76 if (ctx->more_flags & LOCAL) {
77 ret = krb5_auth_con_getremotesubkey(context,
78 ctx->auth_context,
79 key);
80 } else {
81 ret = krb5_auth_con_getlocalsubkey(context,
82 ctx->auth_context,
83 key);
84 }
85 if (ret == 0 && *key == NULL) {
86 krb5_set_error_message(context, 0, "No acceptor subkey available");
87 return GSS_KRB5_S_KG_NO_SUBKEY;
88 }
89 return ret;
90 }
91
92 OM_uint32
_gsskrb5i_get_token_key(const gsskrb5_ctx ctx,krb5_context context,krb5_keyblock ** key)93 _gsskrb5i_get_token_key(const gsskrb5_ctx ctx,
94 krb5_context context,
95 krb5_keyblock **key)
96 {
97 _gsskrb5i_get_acceptor_subkey(ctx, context, key);
98 if(*key == NULL) {
99 /*
100 * Only use the initiator subkey or ticket session key if an
101 * acceptor subkey was not required.
102 */
103 if ((ctx->more_flags & ACCEPTOR_SUBKEY) == 0)
104 _gsskrb5i_get_initiator_subkey(ctx, context, key);
105 }
106 if (*key == NULL) {
107 krb5_set_error_message(context, 0, "No token key available");
108 return GSS_KRB5_S_KG_NO_SUBKEY;
109 }
110 return 0;
111 }
112
113 static OM_uint32
sub_wrap_size(OM_uint32 req_output_size,OM_uint32 * max_input_size,int blocksize,int extrasize)114 sub_wrap_size (
115 OM_uint32 req_output_size,
116 OM_uint32 * max_input_size,
117 int blocksize,
118 int extrasize
119 )
120 {
121 size_t len, total_len;
122
123 len = 8 + req_output_size + blocksize + extrasize;
124
125 _gsskrb5_encap_length(len, &len, &total_len, GSS_KRB5_MECHANISM);
126
127 total_len -= req_output_size; /* token length */
128 if (total_len < req_output_size) {
129 *max_input_size = (req_output_size - total_len);
130 (*max_input_size) &= (~(OM_uint32)(blocksize - 1));
131 } else {
132 *max_input_size = 0;
133 }
134 return GSS_S_COMPLETE;
135 }
136
137 OM_uint32 GSSAPI_CALLCONV
_gsskrb5_wrap_size_limit(OM_uint32 * minor_status,const gss_ctx_id_t context_handle,int conf_req_flag,gss_qop_t qop_req,OM_uint32 req_output_size,OM_uint32 * max_input_size)138 _gsskrb5_wrap_size_limit (
139 OM_uint32 * minor_status,
140 const gss_ctx_id_t context_handle,
141 int conf_req_flag,
142 gss_qop_t qop_req,
143 OM_uint32 req_output_size,
144 OM_uint32 * max_input_size
145 )
146 {
147 krb5_context context;
148 krb5_keyblock *key;
149 OM_uint32 ret;
150 krb5_keytype keytype;
151 const gsskrb5_ctx ctx = (const gsskrb5_ctx) context_handle;
152
153 GSSAPI_KRB5_INIT (&context);
154
155 if (ctx->more_flags & IS_CFX)
156 return _gssapi_wrap_size_cfx(minor_status, ctx, context,
157 conf_req_flag, qop_req,
158 req_output_size, max_input_size);
159
160 HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
161 ret = _gsskrb5i_get_token_key(ctx, context, &key);
162 HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
163 if (ret) {
164 *minor_status = ret;
165 return GSS_S_FAILURE;
166 }
167 krb5_enctype_to_keytype (context, key->keytype, &keytype);
168
169 switch (keytype) {
170 case KEYTYPE_DES :
171 #ifdef HEIM_WEAK_CRYPTO
172 ret = sub_wrap_size(req_output_size, max_input_size, 8, 22);
173 #else
174 ret = GSS_S_FAILURE;
175 #endif
176 break;
177 case ENCTYPE_ARCFOUR_HMAC_MD5:
178 case ENCTYPE_ARCFOUR_HMAC_MD5_56:
179 ret = _gssapi_wrap_size_arcfour(minor_status, ctx, context,
180 conf_req_flag, qop_req,
181 req_output_size, max_input_size, key);
182 break;
183 case KEYTYPE_DES3 :
184 ret = sub_wrap_size(req_output_size, max_input_size, 8, 34);
185 break;
186 default :
187 abort();
188 break;
189 }
190 krb5_free_keyblock (context, key);
191 *minor_status = 0;
192 return ret;
193 }
194
195 #ifdef HEIM_WEAK_CRYPTO
196
197 static OM_uint32
wrap_des(OM_uint32 * minor_status,const gsskrb5_ctx ctx,krb5_context context,int conf_req_flag,gss_qop_t qop_req,const gss_buffer_t input_message_buffer,int * conf_state,gss_buffer_t output_message_buffer,krb5_keyblock * key)198 wrap_des
199 (OM_uint32 * minor_status,
200 const gsskrb5_ctx ctx,
201 krb5_context context,
202 int conf_req_flag,
203 gss_qop_t qop_req,
204 const gss_buffer_t input_message_buffer,
205 int * conf_state,
206 gss_buffer_t output_message_buffer,
207 krb5_keyblock *key
208 )
209 {
210 u_char *p;
211 EVP_MD_CTX *md5;
212 u_char hash[16];
213 DES_key_schedule schedule;
214 EVP_CIPHER_CTX *des_ctx;
215 DES_cblock deskey;
216 DES_cblock zero;
217 size_t i;
218 int32_t seq_number;
219 size_t len, total_len, padlength, datalen;
220
221 if (IS_DCE_STYLE(ctx)) {
222 padlength = 0;
223 datalen = input_message_buffer->length;
224 len = 22 + 8;
225 _gsskrb5_encap_length (len, &len, &total_len, GSS_KRB5_MECHANISM);
226 total_len += datalen;
227 datalen += 8;
228 } else {
229 padlength = 8 - (input_message_buffer->length % 8);
230 datalen = input_message_buffer->length + padlength + 8;
231 len = datalen + 22;
232 _gsskrb5_encap_length (len, &len, &total_len, GSS_KRB5_MECHANISM);
233 }
234
235 output_message_buffer->length = total_len;
236 output_message_buffer->value = malloc (total_len);
237 if (output_message_buffer->value == NULL) {
238 output_message_buffer->length = 0;
239 *minor_status = ENOMEM;
240 return GSS_S_FAILURE;
241 }
242
243 p = _gsskrb5_make_header(output_message_buffer->value,
244 len,
245 "\x02\x01", /* TOK_ID */
246 GSS_KRB5_MECHANISM);
247
248 /* SGN_ALG */
249 memcpy (p, "\x00\x00", 2);
250 p += 2;
251 /* SEAL_ALG */
252 if(conf_req_flag)
253 memcpy (p, "\x00\x00", 2);
254 else
255 memcpy (p, "\xff\xff", 2);
256 p += 2;
257 /* Filler */
258 memcpy (p, "\xff\xff", 2);
259 p += 2;
260
261 /* fill in later */
262 memset (p, 0, 16);
263 p += 16;
264
265 /* confounder + data + pad */
266 krb5_generate_random_block(p, 8);
267 memcpy (p + 8, input_message_buffer->value,
268 input_message_buffer->length);
269 memset (p + 8 + input_message_buffer->length, padlength, padlength);
270
271 /* checksum */
272 md5 = EVP_MD_CTX_create();
273 EVP_DigestInit_ex(md5, EVP_md5(), NULL);
274 EVP_DigestUpdate(md5, p - 24, 8);
275 EVP_DigestUpdate(md5, p, datalen);
276 EVP_DigestFinal_ex(md5, hash, NULL);
277 EVP_MD_CTX_destroy(md5);
278
279 memset (&zero, 0, sizeof(zero));
280 memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
281 DES_set_key_unchecked (&deskey, &schedule);
282 DES_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash),
283 &schedule, &zero);
284 memcpy (p - 8, hash, 8);
285
286 des_ctx = EVP_CIPHER_CTX_new();
287 if (des_ctx == NULL) {
288 memset (deskey, 0, sizeof(deskey));
289 memset (&schedule, 0, sizeof(schedule));
290 free(output_message_buffer->value);
291 output_message_buffer->value = NULL;
292 output_message_buffer->length = 0;
293 *minor_status = ENOMEM;
294 return GSS_S_FAILURE;
295 }
296
297 /* sequence number */
298 HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
299 krb5_auth_con_getlocalseqnumber (context,
300 ctx->auth_context,
301 &seq_number);
302
303 p -= 16;
304 p[0] = (seq_number >> 0) & 0xFF;
305 p[1] = (seq_number >> 8) & 0xFF;
306 p[2] = (seq_number >> 16) & 0xFF;
307 p[3] = (seq_number >> 24) & 0xFF;
308 memset (p + 4,
309 (ctx->more_flags & LOCAL) ? 0 : 0xFF,
310 4);
311
312 EVP_CipherInit_ex(des_ctx, EVP_des_cbc(), NULL, key->keyvalue.data, p + 8, 1);
313 EVP_Cipher(des_ctx, p, p, 8);
314
315 krb5_auth_con_setlocalseqnumber (context,
316 ctx->auth_context,
317 ++seq_number);
318 HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
319
320 /* encrypt the data */
321 p += 16;
322
323 if(conf_req_flag) {
324 memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
325
326 for (i = 0; i < sizeof(deskey); ++i)
327 deskey[i] ^= 0xf0;
328
329 EVP_CIPHER_CTX_reset(des_ctx);
330 EVP_CipherInit_ex(des_ctx, EVP_des_cbc(), NULL, deskey, zero, 1);
331 EVP_Cipher(des_ctx, p, p, datalen);
332 }
333 EVP_CIPHER_CTX_free(des_ctx);
334 memset (deskey, 0, sizeof(deskey));
335 memset (&schedule, 0, sizeof(schedule));
336
337 if(conf_state != NULL)
338 *conf_state = conf_req_flag;
339 *minor_status = 0;
340 return GSS_S_COMPLETE;
341 }
342
343 #endif
344
345 static OM_uint32
wrap_des3(OM_uint32 * minor_status,const gsskrb5_ctx ctx,krb5_context context,int conf_req_flag,gss_qop_t qop_req,const gss_buffer_t input_message_buffer,int * conf_state,gss_buffer_t output_message_buffer,krb5_keyblock * key)346 wrap_des3
347 (OM_uint32 * minor_status,
348 const gsskrb5_ctx ctx,
349 krb5_context context,
350 int conf_req_flag,
351 gss_qop_t qop_req,
352 const gss_buffer_t input_message_buffer,
353 int * conf_state,
354 gss_buffer_t output_message_buffer,
355 krb5_keyblock *key
356 )
357 {
358 u_char *p;
359 u_char seq[8];
360 int32_t seq_number;
361 size_t len, total_len, padlength, datalen;
362 uint32_t ret;
363 krb5_crypto crypto;
364 Checksum cksum;
365 krb5_data encdata;
366
367 if (IS_DCE_STYLE(ctx)) {
368 padlength = 0;
369 datalen = input_message_buffer->length;
370 len = 34 + 8;
371 _gsskrb5_encap_length (len, &len, &total_len, GSS_KRB5_MECHANISM);
372 total_len += datalen;
373 datalen += 8;
374 } else {
375 padlength = 8 - (input_message_buffer->length % 8);
376 datalen = input_message_buffer->length + padlength + 8;
377 len = datalen + 34;
378 _gsskrb5_encap_length (len, &len, &total_len, GSS_KRB5_MECHANISM);
379 }
380
381 output_message_buffer->length = total_len;
382 output_message_buffer->value = malloc (total_len);
383 if (output_message_buffer->value == NULL) {
384 output_message_buffer->length = 0;
385 *minor_status = ENOMEM;
386 return GSS_S_FAILURE;
387 }
388
389 p = _gsskrb5_make_header(output_message_buffer->value,
390 len,
391 "\x02\x01", /* TOK_ID */
392 GSS_KRB5_MECHANISM);
393
394 /* SGN_ALG */
395 memcpy (p, "\x04\x00", 2); /* HMAC SHA1 DES3-KD */
396 p += 2;
397 /* SEAL_ALG */
398 if(conf_req_flag)
399 memcpy (p, "\x02\x00", 2); /* DES3-KD */
400 else
401 memcpy (p, "\xff\xff", 2);
402 p += 2;
403 /* Filler */
404 memcpy (p, "\xff\xff", 2);
405 p += 2;
406
407 /* calculate checksum (the above + confounder + data + pad) */
408
409 memcpy (p + 20, p - 8, 8);
410 krb5_generate_random_block(p + 28, 8);
411 memcpy (p + 28 + 8, input_message_buffer->value,
412 input_message_buffer->length);
413 memset (p + 28 + 8 + input_message_buffer->length, padlength, padlength);
414
415 ret = krb5_crypto_init(context, key, 0, &crypto);
416 if (ret) {
417 free (output_message_buffer->value);
418 output_message_buffer->length = 0;
419 output_message_buffer->value = NULL;
420 *minor_status = ret;
421 return GSS_S_FAILURE;
422 }
423
424 ret = krb5_create_checksum (context,
425 crypto,
426 KRB5_KU_USAGE_SIGN,
427 0,
428 p + 20,
429 datalen + 8,
430 &cksum);
431 krb5_crypto_destroy (context, crypto);
432 if (ret) {
433 free (output_message_buffer->value);
434 output_message_buffer->length = 0;
435 output_message_buffer->value = NULL;
436 *minor_status = ret;
437 return GSS_S_FAILURE;
438 }
439
440 /* zero out SND_SEQ + SGN_CKSUM in case */
441 memset (p, 0, 28);
442
443 memcpy (p + 8, cksum.checksum.data, cksum.checksum.length);
444 free_Checksum (&cksum);
445
446 HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
447 /* sequence number */
448 krb5_auth_con_getlocalseqnumber (context,
449 ctx->auth_context,
450 &seq_number);
451
452 seq[0] = (seq_number >> 0) & 0xFF;
453 seq[1] = (seq_number >> 8) & 0xFF;
454 seq[2] = (seq_number >> 16) & 0xFF;
455 seq[3] = (seq_number >> 24) & 0xFF;
456 memset (seq + 4,
457 (ctx->more_flags & LOCAL) ? 0 : 0xFF,
458 4);
459
460
461 ret = krb5_crypto_init(context, key, ETYPE_DES3_CBC_NONE,
462 &crypto);
463 if (ret) {
464 free (output_message_buffer->value);
465 output_message_buffer->length = 0;
466 output_message_buffer->value = NULL;
467 *minor_status = ret;
468 return GSS_S_FAILURE;
469 }
470
471 {
472 DES_cblock ivec;
473
474 memcpy (&ivec, p + 8, 8);
475 ret = krb5_encrypt_ivec (context,
476 crypto,
477 KRB5_KU_USAGE_SEQ,
478 seq, 8, &encdata,
479 &ivec);
480 }
481 krb5_crypto_destroy (context, crypto);
482 if (ret) {
483 free (output_message_buffer->value);
484 output_message_buffer->length = 0;
485 output_message_buffer->value = NULL;
486 *minor_status = ret;
487 return GSS_S_FAILURE;
488 }
489
490 assert (encdata.length == 8);
491
492 memcpy (p, encdata.data, encdata.length);
493 krb5_data_free (&encdata);
494
495 krb5_auth_con_setlocalseqnumber (context,
496 ctx->auth_context,
497 ++seq_number);
498 HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
499
500 /* encrypt the data */
501 p += 28;
502
503 if(conf_req_flag) {
504 krb5_data tmp;
505
506 ret = krb5_crypto_init(context, key,
507 ETYPE_DES3_CBC_NONE, &crypto);
508 if (ret) {
509 free (output_message_buffer->value);
510 output_message_buffer->length = 0;
511 output_message_buffer->value = NULL;
512 *minor_status = ret;
513 return GSS_S_FAILURE;
514 }
515 ret = krb5_encrypt(context, crypto, KRB5_KU_USAGE_SEAL,
516 p, datalen, &tmp);
517 krb5_crypto_destroy(context, crypto);
518 if (ret) {
519 free (output_message_buffer->value);
520 output_message_buffer->length = 0;
521 output_message_buffer->value = NULL;
522 *minor_status = ret;
523 return GSS_S_FAILURE;
524 }
525 assert (tmp.length == datalen);
526
527 memcpy (p, tmp.data, datalen);
528 krb5_data_free(&tmp);
529 }
530 if(conf_state != NULL)
531 *conf_state = conf_req_flag;
532 *minor_status = 0;
533 return GSS_S_COMPLETE;
534 }
535
536 OM_uint32 GSSAPI_CALLCONV
_gsskrb5_wrap(OM_uint32 * minor_status,const gss_ctx_id_t context_handle,int conf_req_flag,gss_qop_t qop_req,const gss_buffer_t input_message_buffer,int * conf_state,gss_buffer_t output_message_buffer)537 _gsskrb5_wrap
538 (OM_uint32 * minor_status,
539 const gss_ctx_id_t context_handle,
540 int conf_req_flag,
541 gss_qop_t qop_req,
542 const gss_buffer_t input_message_buffer,
543 int * conf_state,
544 gss_buffer_t output_message_buffer
545 )
546 {
547 krb5_context context;
548 krb5_keyblock *key;
549 OM_uint32 ret;
550 krb5_keytype keytype;
551 const gsskrb5_ctx ctx = (const gsskrb5_ctx) context_handle;
552
553 output_message_buffer->value = NULL;
554 output_message_buffer->length = 0;
555
556 GSSAPI_KRB5_INIT (&context);
557
558 if (ctx->more_flags & IS_CFX)
559 return _gssapi_wrap_cfx (minor_status, ctx, context, conf_req_flag,
560 input_message_buffer, conf_state,
561 output_message_buffer);
562
563 HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
564 ret = _gsskrb5i_get_token_key(ctx, context, &key);
565 HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
566 if (ret) {
567 *minor_status = ret;
568 return GSS_S_FAILURE;
569 }
570 krb5_enctype_to_keytype (context, key->keytype, &keytype);
571
572 switch (keytype) {
573 case KEYTYPE_DES :
574 #ifdef HEIM_WEAK_CRYPTO
575 ret = wrap_des (minor_status, ctx, context, conf_req_flag,
576 qop_req, input_message_buffer, conf_state,
577 output_message_buffer, key);
578 #else
579 ret = GSS_S_FAILURE;
580 #endif
581 break;
582 case KEYTYPE_DES3 :
583 ret = wrap_des3 (minor_status, ctx, context, conf_req_flag,
584 qop_req, input_message_buffer, conf_state,
585 output_message_buffer, key);
586 break;
587 case KEYTYPE_ARCFOUR:
588 case KEYTYPE_ARCFOUR_56:
589 ret = _gssapi_wrap_arcfour (minor_status, ctx, context, conf_req_flag,
590 qop_req, input_message_buffer, conf_state,
591 output_message_buffer, key);
592 break;
593 default :
594 abort();
595 break;
596 }
597 krb5_free_keyblock (context, key);
598 return ret;
599 }
600