source: heimdal/trunk/lib/gssapi/krb5/wrap.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: 15.8 KB
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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
40krb5_error_code
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
68krb5_error_code
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
92OM_uint32
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
113static OM_uint32
114sub_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
137OM_uint32 GSSAPI_CALLCONV
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
197static OM_uint32
198wrap_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 /* sequence number */
287 HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
288 krb5_auth_con_getlocalseqnumber (context,
289 ctx->auth_context,
290 &seq_number);
291
292 p -= 16;
293 p[0] = (seq_number >> 0) & 0xFF;
294 p[1] = (seq_number >> 8) & 0xFF;
295 p[2] = (seq_number >> 16) & 0xFF;
296 p[3] = (seq_number >> 24) & 0xFF;
297 memset (p + 4,
298 (ctx->more_flags & LOCAL) ? 0 : 0xFF,
299 4);
300
301 EVP_CIPHER_CTX_init(&des_ctx);
302 EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, key->keyvalue.data, p + 8, 1);
303 EVP_Cipher(&des_ctx, p, p, 8);
304 EVP_CIPHER_CTX_cleanup(&des_ctx);
305
306 krb5_auth_con_setlocalseqnumber (context,
307 ctx->auth_context,
308 ++seq_number);
309 HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
310
311 /* encrypt the data */
312 p += 16;
313
314 if(conf_req_flag) {
315 memcpy (&deskey, key->keyvalue.data, sizeof(deskey));
316
317 for (i = 0; i < sizeof(deskey); ++i)
318 deskey[i] ^= 0xf0;
319
320 EVP_CIPHER_CTX_init(&des_ctx);
321 EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, deskey, zero, 1);
322 EVP_Cipher(&des_ctx, p, p, datalen);
323 EVP_CIPHER_CTX_cleanup(&des_ctx);
324 }
325 memset (deskey, 0, sizeof(deskey));
326 memset (&schedule, 0, sizeof(schedule));
327
328 if(conf_state != NULL)
329 *conf_state = conf_req_flag;
330 *minor_status = 0;
331 return GSS_S_COMPLETE;
332}
333
334#endif
335
336static OM_uint32
337wrap_des3
338 (OM_uint32 * minor_status,
339 const gsskrb5_ctx ctx,
340 krb5_context context,
341 int conf_req_flag,
342 gss_qop_t qop_req,
343 const gss_buffer_t input_message_buffer,
344 int * conf_state,
345 gss_buffer_t output_message_buffer,
346 krb5_keyblock *key
347 )
348{
349 u_char *p;
350 u_char seq[8];
351 int32_t seq_number;
352 size_t len, total_len, padlength, datalen;
353 uint32_t ret;
354 krb5_crypto crypto;
355 Checksum cksum;
356 krb5_data encdata;
357
358 if (IS_DCE_STYLE(ctx)) {
359 padlength = 0;
360 datalen = input_message_buffer->length;
361 len = 34 + 8;
362 _gsskrb5_encap_length (len, &len, &total_len, GSS_KRB5_MECHANISM);
363 total_len += datalen;
364 datalen += 8;
365 } else {
366 padlength = 8 - (input_message_buffer->length % 8);
367 datalen = input_message_buffer->length + padlength + 8;
368 len = datalen + 34;
369 _gsskrb5_encap_length (len, &len, &total_len, GSS_KRB5_MECHANISM);
370 }
371
372 output_message_buffer->length = total_len;
373 output_message_buffer->value = malloc (total_len);
374 if (output_message_buffer->value == NULL) {
375 output_message_buffer->length = 0;
376 *minor_status = ENOMEM;
377 return GSS_S_FAILURE;
378 }
379
380 p = _gsskrb5_make_header(output_message_buffer->value,
381 len,
382 "\x02\x01", /* TOK_ID */
383 GSS_KRB5_MECHANISM);
384
385 /* SGN_ALG */
386 memcpy (p, "\x04\x00", 2); /* HMAC SHA1 DES3-KD */
387 p += 2;
388 /* SEAL_ALG */
389 if(conf_req_flag)
390 memcpy (p, "\x02\x00", 2); /* DES3-KD */
391 else
392 memcpy (p, "\xff\xff", 2);
393 p += 2;
394 /* Filler */
395 memcpy (p, "\xff\xff", 2);
396 p += 2;
397
398 /* calculate checksum (the above + confounder + data + pad) */
399
400 memcpy (p + 20, p - 8, 8);
401 krb5_generate_random_block(p + 28, 8);
402 memcpy (p + 28 + 8, input_message_buffer->value,
403 input_message_buffer->length);
404 memset (p + 28 + 8 + input_message_buffer->length, padlength, padlength);
405
406 ret = krb5_crypto_init(context, key, 0, &crypto);
407 if (ret) {
408 free (output_message_buffer->value);
409 output_message_buffer->length = 0;
410 output_message_buffer->value = NULL;
411 *minor_status = ret;
412 return GSS_S_FAILURE;
413 }
414
415 ret = krb5_create_checksum (context,
416 crypto,
417 KRB5_KU_USAGE_SIGN,
418 0,
419 p + 20,
420 datalen + 8,
421 &cksum);
422 krb5_crypto_destroy (context, crypto);
423 if (ret) {
424 free (output_message_buffer->value);
425 output_message_buffer->length = 0;
426 output_message_buffer->value = NULL;
427 *minor_status = ret;
428 return GSS_S_FAILURE;
429 }
430
431 /* zero out SND_SEQ + SGN_CKSUM in case */
432 memset (p, 0, 28);
433
434 memcpy (p + 8, cksum.checksum.data, cksum.checksum.length);
435 free_Checksum (&cksum);
436
437 HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
438 /* sequence number */
439 krb5_auth_con_getlocalseqnumber (context,
440 ctx->auth_context,
441 &seq_number);
442
443 seq[0] = (seq_number >> 0) & 0xFF;
444 seq[1] = (seq_number >> 8) & 0xFF;
445 seq[2] = (seq_number >> 16) & 0xFF;
446 seq[3] = (seq_number >> 24) & 0xFF;
447 memset (seq + 4,
448 (ctx->more_flags & LOCAL) ? 0 : 0xFF,
449 4);
450
451
452 ret = krb5_crypto_init(context, key, ETYPE_DES3_CBC_NONE,
453 &crypto);
454 if (ret) {
455 free (output_message_buffer->value);
456 output_message_buffer->length = 0;
457 output_message_buffer->value = NULL;
458 *minor_status = ret;
459 return GSS_S_FAILURE;
460 }
461
462 {
463 DES_cblock ivec;
464
465 memcpy (&ivec, p + 8, 8);
466 ret = krb5_encrypt_ivec (context,
467 crypto,
468 KRB5_KU_USAGE_SEQ,
469 seq, 8, &encdata,
470 &ivec);
471 }
472 krb5_crypto_destroy (context, crypto);
473 if (ret) {
474 free (output_message_buffer->value);
475 output_message_buffer->length = 0;
476 output_message_buffer->value = NULL;
477 *minor_status = ret;
478 return GSS_S_FAILURE;
479 }
480
481 assert (encdata.length == 8);
482
483 memcpy (p, encdata.data, encdata.length);
484 krb5_data_free (&encdata);
485
486 krb5_auth_con_setlocalseqnumber (context,
487 ctx->auth_context,
488 ++seq_number);
489 HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
490
491 /* encrypt the data */
492 p += 28;
493
494 if(conf_req_flag) {
495 krb5_data tmp;
496
497 ret = krb5_crypto_init(context, key,
498 ETYPE_DES3_CBC_NONE, &crypto);
499 if (ret) {
500 free (output_message_buffer->value);
501 output_message_buffer->length = 0;
502 output_message_buffer->value = NULL;
503 *minor_status = ret;
504 return GSS_S_FAILURE;
505 }
506 ret = krb5_encrypt(context, crypto, KRB5_KU_USAGE_SEAL,
507 p, datalen, &tmp);
508 krb5_crypto_destroy(context, crypto);
509 if (ret) {
510 free (output_message_buffer->value);
511 output_message_buffer->length = 0;
512 output_message_buffer->value = NULL;
513 *minor_status = ret;
514 return GSS_S_FAILURE;
515 }
516 assert (tmp.length == datalen);
517
518 memcpy (p, tmp.data, datalen);
519 krb5_data_free(&tmp);
520 }
521 if(conf_state != NULL)
522 *conf_state = conf_req_flag;
523 *minor_status = 0;
524 return GSS_S_COMPLETE;
525}
526
527OM_uint32 GSSAPI_CALLCONV
528_gsskrb5_wrap
529 (OM_uint32 * minor_status,
530 const gss_ctx_id_t context_handle,
531 int conf_req_flag,
532 gss_qop_t qop_req,
533 const gss_buffer_t input_message_buffer,
534 int * conf_state,
535 gss_buffer_t output_message_buffer
536 )
537{
538 krb5_context context;
539 krb5_keyblock *key;
540 OM_uint32 ret;
541 krb5_keytype keytype;
542 const gsskrb5_ctx ctx = (const gsskrb5_ctx) context_handle;
543
544 output_message_buffer->value = NULL;
545 output_message_buffer->length = 0;
546
547 GSSAPI_KRB5_INIT (&context);
548
549 if (ctx->more_flags & IS_CFX)
550 return _gssapi_wrap_cfx (minor_status, ctx, context, conf_req_flag,
551 input_message_buffer, conf_state,
552 output_message_buffer);
553
554 HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex);
555 ret = _gsskrb5i_get_token_key(ctx, context, &key);
556 HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex);
557 if (ret) {
558 *minor_status = ret;
559 return GSS_S_FAILURE;
560 }
561 krb5_enctype_to_keytype (context, key->keytype, &keytype);
562
563 switch (keytype) {
564 case KEYTYPE_DES :
565#ifdef HEIM_WEAK_CRYPTO
566 ret = wrap_des (minor_status, ctx, context, conf_req_flag,
567 qop_req, input_message_buffer, conf_state,
568 output_message_buffer, key);
569#else
570 ret = GSS_S_FAILURE;
571#endif
572 break;
573 case KEYTYPE_DES3 :
574 ret = wrap_des3 (minor_status, ctx, context, conf_req_flag,
575 qop_req, input_message_buffer, conf_state,
576 output_message_buffer, key);
577 break;
578 case KEYTYPE_ARCFOUR:
579 case KEYTYPE_ARCFOUR_56:
580 ret = _gssapi_wrap_arcfour (minor_status, ctx, context, conf_req_flag,
581 qop_req, input_message_buffer, conf_state,
582 output_message_buffer, key);
583 break;
584 default :
585 abort();
586 break;
587 }
588 krb5_free_keyblock (context, key);
589 return ret;
590}
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