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}
591