build: a more portable way of finding waf in makefiles
[sfrench/samba-autobuild/.git] / libcli / auth / ntlmssp_sign.c
1 /*
2  *  Unix SMB/CIFS implementation.
3  *  Version 3.0
4  *  NTLMSSP Signing routines
5  *  Copyright (C) Andrew Bartlett 2003-2005
6  *
7  *  This program is free software; you can redistribute it and/or modify
8  *  it under the terms of the GNU General Public License as published by
9  *  the Free Software Foundation; either version 3 of the License, or
10  *  (at your option) any later version.
11  *
12  *  This program is distributed in the hope that it will be useful,
13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *  GNU General Public License for more details.
16  *
17  *  You should have received a copy of the GNU General Public License
18  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
19  */
20
21 #include "includes.h"
22 #include "../libcli/auth/ntlmssp.h"
23 #include "../libcli/auth/libcli_auth.h"
24 #include "../lib/crypto/md5.h"
25 #include "../lib/crypto/hmacmd5.h"
26 #include "../lib/crypto/crc32.h"
27 #include "../libcli/auth/ntlmssp_private.h"
28
29 #define CLI_SIGN "session key to client-to-server signing key magic constant"
30 #define CLI_SEAL "session key to client-to-server sealing key magic constant"
31 #define SRV_SIGN "session key to server-to-client signing key magic constant"
32 #define SRV_SEAL "session key to server-to-client sealing key magic constant"
33
34 /**
35  * Some notes on the NTLM2 code:
36  *
37  * NTLM2 is a AEAD system.  This means that the data encrypted is not
38  * all the data that is signed.  In DCE-RPC case, the headers of the
39  * DCE-RPC packets are also signed.  This prevents some of the
40  * fun-and-games one might have by changing them.
41  *
42  */
43
44 static void dump_arc4_state(const char *description,
45                             struct arcfour_state *state)
46 {
47         dump_data_pw(description, state->sbox, sizeof(state->sbox));
48 }
49
50 static void calc_ntlmv2_key(uint8_t subkey[16],
51                             DATA_BLOB session_key,
52                             const char *constant)
53 {
54         struct MD5Context ctx3;
55         MD5Init(&ctx3);
56         MD5Update(&ctx3, session_key.data, session_key.length);
57         MD5Update(&ctx3, (const uint8_t *)constant, strlen(constant)+1);
58         MD5Final(subkey, &ctx3);
59 }
60
61 enum ntlmssp_direction {
62         NTLMSSP_SEND,
63         NTLMSSP_RECEIVE
64 };
65
66 static NTSTATUS ntlmssp_make_packet_signature(struct ntlmssp_state *ntlmssp_state,
67                                               TALLOC_CTX *sig_mem_ctx,
68                                               const uint8_t *data, size_t length,
69                                               const uint8_t *whole_pdu, size_t pdu_length,
70                                               enum ntlmssp_direction direction,
71                                               DATA_BLOB *sig, bool encrypt_sig)
72 {
73         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
74                 HMACMD5Context ctx;
75                 uint8_t digest[16];
76                 uint8_t seq_num[4];
77
78                 *sig = data_blob_talloc(sig_mem_ctx, NULL, NTLMSSP_SIG_SIZE);
79                 if (!sig->data) {
80                         return NT_STATUS_NO_MEMORY;
81                 }
82
83                 switch (direction) {
84                 case NTLMSSP_SEND:
85                         DEBUG(100,("ntlmssp_make_packet_signature: SEND seq = %u, len = %u, pdu_len = %u\n",
86                                 ntlmssp_state->crypt->ntlm2.sending.seq_num,
87                                 (unsigned int)length,
88                                 (unsigned int)pdu_length));
89
90                         SIVAL(seq_num, 0, ntlmssp_state->crypt->ntlm2.sending.seq_num);
91                         ntlmssp_state->crypt->ntlm2.sending.seq_num++;
92                         hmac_md5_init_limK_to_64(ntlmssp_state->crypt->ntlm2.sending.sign_key, 16, &ctx);
93                         break;
94                 case NTLMSSP_RECEIVE:
95
96                         DEBUG(100,("ntlmssp_make_packet_signature: RECV seq = %u, len = %u, pdu_len = %u\n",
97                                 ntlmssp_state->crypt->ntlm2.receiving.seq_num,
98                                 (unsigned int)length,
99                                 (unsigned int)pdu_length));
100
101                         SIVAL(seq_num, 0, ntlmssp_state->crypt->ntlm2.receiving.seq_num);
102                         ntlmssp_state->crypt->ntlm2.receiving.seq_num++;
103                         hmac_md5_init_limK_to_64(ntlmssp_state->crypt->ntlm2.receiving.sign_key, 16, &ctx);
104                         break;
105                 }
106
107                 dump_data_pw("pdu data ", whole_pdu, pdu_length);
108
109                 hmac_md5_update(seq_num, sizeof(seq_num), &ctx);
110                 hmac_md5_update(whole_pdu, pdu_length, &ctx);
111                 hmac_md5_final(digest, &ctx);
112
113                 if (encrypt_sig && (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH)) {
114                         switch (direction) {
115                         case NTLMSSP_SEND:
116                                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
117                                                    digest, 8);
118                                 break;
119                         case NTLMSSP_RECEIVE:
120                                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.receiving.seal_state,
121                                                    digest, 8);
122                                 break;
123                         }
124                 }
125
126                 SIVAL(sig->data, 0, NTLMSSP_SIGN_VERSION);
127                 memcpy(sig->data + 4, digest, 8);
128                 memcpy(sig->data + 12, seq_num, 4);
129
130                 dump_data_pw("ntlmssp v2 sig ", sig->data, sig->length);
131
132         } else {
133                 bool ok;
134                 uint32_t crc;
135
136                 crc = crc32_calc_buffer(data, length);
137
138                 ok = msrpc_gen(sig_mem_ctx,
139                                sig, "dddd",
140                                NTLMSSP_SIGN_VERSION, 0, crc,
141                                ntlmssp_state->crypt->ntlm.seq_num);
142                 if (!ok) {
143                         return NT_STATUS_NO_MEMORY;
144                 }
145
146                 ntlmssp_state->crypt->ntlm.seq_num++;
147
148                 dump_arc4_state("ntlmssp hash: \n",
149                                 &ntlmssp_state->crypt->ntlm.seal_state);
150                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
151                                    sig->data+4, sig->length-4);
152         }
153         return NT_STATUS_OK;
154 }
155
156 NTSTATUS ntlmssp_sign_packet(struct ntlmssp_state *ntlmssp_state,
157                              TALLOC_CTX *sig_mem_ctx,
158                              const uint8_t *data, size_t length,
159                              const uint8_t *whole_pdu, size_t pdu_length,
160                              DATA_BLOB *sig)
161 {
162         NTSTATUS nt_status;
163
164         if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN)) {
165                 DEBUG(3, ("NTLMSSP Signing not negotiated - cannot sign packet!\n"));
166                 return NT_STATUS_INVALID_PARAMETER;
167         }
168
169         if (!ntlmssp_state->session_key.length) {
170                 DEBUG(3, ("NO session key, cannot check sign packet\n"));
171                 return NT_STATUS_NO_USER_SESSION_KEY;
172         }
173
174         nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
175                                                   sig_mem_ctx,
176                                                   data, length,
177                                                   whole_pdu, pdu_length,
178                                                   NTLMSSP_SEND, sig, true);
179
180         return nt_status;
181 }
182
183 /**
184  * Check the signature of an incoming packet
185  * @note caller *must* check that the signature is the size it expects
186  *
187  */
188
189 NTSTATUS ntlmssp_check_packet(struct ntlmssp_state *ntlmssp_state,
190                               const uint8_t *data, size_t length,
191                               const uint8_t *whole_pdu, size_t pdu_length,
192                               const DATA_BLOB *sig)
193 {
194         DATA_BLOB local_sig;
195         NTSTATUS nt_status;
196         TALLOC_CTX *tmp_ctx;
197
198         if (!ntlmssp_state->session_key.length) {
199                 DEBUG(3, ("NO session key, cannot check packet signature\n"));
200                 return NT_STATUS_NO_USER_SESSION_KEY;
201         }
202
203         if (sig->length < 8) {
204                 DEBUG(0, ("NTLMSSP packet check failed due to short signature (%lu bytes)!\n",
205                           (unsigned long)sig->length));
206         }
207
208         tmp_ctx = talloc_new(ntlmssp_state);
209         if (!tmp_ctx) {
210                 return NT_STATUS_NO_MEMORY;
211         }
212
213         nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
214                                                   tmp_ctx,
215                                                   data, length,
216                                                   whole_pdu, pdu_length,
217                                                   NTLMSSP_RECEIVE,
218                                                   &local_sig, true);
219
220         if (!NT_STATUS_IS_OK(nt_status)) {
221                 DEBUG(0,("NTLMSSP packet sig creation failed with %s\n",
222                          nt_errstr(nt_status)));
223                 talloc_free(tmp_ctx);
224                 return nt_status;
225         }
226
227         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
228                 if (local_sig.length != sig->length ||
229                     memcmp(local_sig.data, sig->data, sig->length) != 0) {
230                         DEBUG(5, ("BAD SIG NTLM2: wanted signature of\n"));
231                         dump_data(5, local_sig.data, local_sig.length);
232
233                         DEBUG(5, ("BAD SIG: got signature of\n"));
234                         dump_data(5, sig->data, sig->length);
235
236                         DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n"));
237                         talloc_free(tmp_ctx);
238                         return NT_STATUS_ACCESS_DENIED;
239                 }
240         } else {
241                 if (local_sig.length != sig->length ||
242                     memcmp(local_sig.data + 8, sig->data + 8, sig->length - 8) != 0) {
243                         DEBUG(5, ("BAD SIG NTLM1: wanted signature of\n"));
244                         dump_data(5, local_sig.data, local_sig.length);
245
246                         DEBUG(5, ("BAD SIG: got signature of\n"));
247                         dump_data(5, sig->data, sig->length);
248
249                         DEBUG(0, ("NTLMSSP NTLM1 packet check failed due to invalid signature!\n"));
250                         talloc_free(tmp_ctx);
251                         return NT_STATUS_ACCESS_DENIED;
252                 }
253         }
254         dump_data_pw("checked ntlmssp signature\n", sig->data, sig->length);
255         DEBUG(10,("ntlmssp_check_packet: NTLMSSP signature OK !\n"));
256
257         talloc_free(tmp_ctx);
258         return NT_STATUS_OK;
259 }
260
261 /**
262  * Seal data with the NTLMSSP algorithm
263  *
264  */
265
266 NTSTATUS ntlmssp_seal_packet(struct ntlmssp_state *ntlmssp_state,
267                              TALLOC_CTX *sig_mem_ctx,
268                              uint8_t *data, size_t length,
269                              const uint8_t *whole_pdu, size_t pdu_length,
270                              DATA_BLOB *sig)
271 {
272         if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL)) {
273                 DEBUG(3, ("NTLMSSP Sealing not negotiated - cannot seal packet!\n"));
274                 return NT_STATUS_INVALID_PARAMETER;
275         }
276
277         if (!ntlmssp_state->session_key.length) {
278                 DEBUG(3, ("NO session key, cannot seal packet\n"));
279                 return NT_STATUS_NO_USER_SESSION_KEY;
280         }
281
282         DEBUG(10,("ntlmssp_seal_data: seal\n"));
283         dump_data_pw("ntlmssp clear data\n", data, length);
284         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
285                 NTSTATUS nt_status;
286                 /*
287                  * The order of these two operations matters - we
288                  * must first seal the packet, then seal the
289                  * sequence number - this is because the
290                  * send_seal_hash is not constant, but is is rather
291                  * updated with each iteration
292                  */
293                 nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
294                                                           sig_mem_ctx,
295                                                           data, length,
296                                                           whole_pdu, pdu_length,
297                                                           NTLMSSP_SEND,
298                                                           sig, false);
299                 if (!NT_STATUS_IS_OK(nt_status)) {
300                         return nt_status;
301                 }
302
303                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
304                                    data, length);
305                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
306                         arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
307                                            sig->data+4, 8);
308                 }
309         } else {
310                 bool ok;
311                 uint32_t crc;
312
313                 crc = crc32_calc_buffer(data, length);
314
315                 ok = msrpc_gen(sig_mem_ctx,
316                                sig, "dddd",
317                                NTLMSSP_SIGN_VERSION, 0, crc,
318                                ntlmssp_state->crypt->ntlm.seq_num);
319                 if (!ok) {
320                         return NT_STATUS_NO_MEMORY;
321                 }
322
323                 /*
324                  * The order of these two operations matters - we
325                  * must first seal the packet, then seal the
326                  * sequence number - this is because the ntlmv1_arc4_state
327                  * is not constant, but is is rather updated with
328                  * each iteration
329                  */
330
331                 dump_arc4_state("ntlmv1 arc4 state:\n",
332                                 &ntlmssp_state->crypt->ntlm.seal_state);
333                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
334                                    data, length);
335
336                 dump_arc4_state("ntlmv1 arc4 state:\n",
337                                 &ntlmssp_state->crypt->ntlm.seal_state);
338
339                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
340                                    sig->data+4, sig->length-4);
341
342                 ntlmssp_state->crypt->ntlm.seq_num++;
343         }
344         dump_data_pw("ntlmssp signature\n", sig->data, sig->length);
345         dump_data_pw("ntlmssp sealed data\n", data, length);
346
347         return NT_STATUS_OK;
348 }
349
350 /**
351  * Unseal data with the NTLMSSP algorithm
352  *
353  */
354
355 NTSTATUS ntlmssp_unseal_packet(struct ntlmssp_state *ntlmssp_state,
356                                uint8_t *data, size_t length,
357                                const uint8_t *whole_pdu, size_t pdu_length,
358                                const DATA_BLOB *sig)
359 {
360         NTSTATUS status;
361         if (!ntlmssp_state->session_key.length) {
362                 DEBUG(3, ("NO session key, cannot unseal packet\n"));
363                 return NT_STATUS_NO_USER_SESSION_KEY;
364         }
365
366         DEBUG(10,("ntlmssp_unseal_packet: seal\n"));
367         dump_data_pw("ntlmssp sealed data\n", data, length);
368
369         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
370                 /* First unseal the data. */
371                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.receiving.seal_state,
372                                    data, length);
373                 dump_data_pw("ntlmv2 clear data\n", data, length);
374         } else {
375                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
376                                    data, length);
377                 dump_data_pw("ntlmv1 clear data\n", data, length);
378         }
379         status = ntlmssp_check_packet(ntlmssp_state,
380                                       data, length,
381                                       whole_pdu, pdu_length,
382                                       sig);
383
384         if (!NT_STATUS_IS_OK(status)) {
385                 DEBUG(1,("NTLMSSP packet check for unseal failed due to invalid signature on %llu bytes of input:\n",
386                          (unsigned long long)length));
387         }
388         return status;
389 }
390
391 /**
392    Initialise the state for NTLMSSP signing.
393 */
394 NTSTATUS ntlmssp_sign_init(struct ntlmssp_state *ntlmssp_state)
395 {
396         DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
397         debug_ntlmssp_flags(ntlmssp_state->neg_flags);
398
399         if (ntlmssp_state->session_key.length < 8) {
400                 DEBUG(3, ("NO session key, cannot intialise signing\n"));
401                 return NT_STATUS_NO_USER_SESSION_KEY;
402         }
403
404         ntlmssp_state->crypt = talloc_zero(ntlmssp_state,
405                                            union ntlmssp_crypt_state);
406         if (ntlmssp_state->crypt == NULL) {
407                 return NT_STATUS_NO_MEMORY;
408         }
409
410         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
411                 DATA_BLOB weak_session_key = ntlmssp_state->session_key;
412                 const char *send_sign_const;
413                 const char *send_seal_const;
414                 const char *recv_sign_const;
415                 const char *recv_seal_const;
416                 uint8_t send_seal_key[16];
417                 DATA_BLOB send_seal_blob = data_blob_const(send_seal_key,
418                                            sizeof(send_seal_key));
419                 uint8_t recv_seal_key[16];
420                 DATA_BLOB recv_seal_blob = data_blob_const(recv_seal_key,
421                                            sizeof(recv_seal_key));
422
423                 switch (ntlmssp_state->role) {
424                 case NTLMSSP_CLIENT:
425                         send_sign_const = CLI_SIGN;
426                         send_seal_const = CLI_SEAL;
427                         recv_sign_const = SRV_SIGN;
428                         recv_seal_const = SRV_SEAL;
429                         break;
430                 case NTLMSSP_SERVER:
431                         send_sign_const = SRV_SIGN;
432                         send_seal_const = SRV_SEAL;
433                         recv_sign_const = CLI_SIGN;
434                         recv_seal_const = CLI_SEAL;
435                         break;
436                 default:
437                         return NT_STATUS_INTERNAL_ERROR;
438                 }
439
440                 /*
441                  * Weaken NTLMSSP keys to cope with down-level
442                  * clients, servers and export restrictions.
443                  *
444                  * We probably should have some parameters to
445                  * control this, once we get NTLM2 working.
446                  *
447                  * Key weakening was not performed on the master key
448                  * for NTLM2, but must be done on the encryption subkeys only.
449                  */
450
451                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
452                         /* nothing to do */
453                 } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
454                         weak_session_key.length = 7;
455                 } else { /* forty bits */
456                         weak_session_key.length = 5;
457                 }
458
459                 dump_data_pw("NTLMSSP weakend master key:\n",
460                              weak_session_key.data,
461                              weak_session_key.length);
462
463                 /* SEND: sign key */
464                 calc_ntlmv2_key(ntlmssp_state->crypt->ntlm2.sending.sign_key,
465                                 ntlmssp_state->session_key, send_sign_const);
466                 dump_data_pw("NTLMSSP send sign key:\n",
467                              ntlmssp_state->crypt->ntlm2.sending.sign_key, 16);
468
469                 /* SEND: seal ARCFOUR pad */
470                 calc_ntlmv2_key(send_seal_key,
471                                 weak_session_key, send_seal_const);
472                 dump_data_pw("NTLMSSP send seal key:\n", send_seal_key, 16);
473
474                 arcfour_init(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
475                              &send_seal_blob);
476
477                 dump_arc4_state("NTLMSSP send seal arc4 state:\n",
478                                 &ntlmssp_state->crypt->ntlm2.sending.seal_state);
479
480                 /* SEND: seq num */
481                 ntlmssp_state->crypt->ntlm2.sending.seq_num = 0;
482
483                 /* RECV: sign key */
484                 calc_ntlmv2_key(ntlmssp_state->crypt->ntlm2.receiving.sign_key,
485                                 ntlmssp_state->session_key, recv_sign_const);
486                 dump_data_pw("NTLMSSP recv sign key:\n",
487                              ntlmssp_state->crypt->ntlm2.receiving.sign_key, 16);
488
489                 /* RECV: seal ARCFOUR pad */
490                 calc_ntlmv2_key(recv_seal_key,
491                                 weak_session_key, recv_seal_const);
492                 dump_data_pw("NTLMSSP recv seal key:\n", recv_seal_key, 16);
493
494                 arcfour_init(&ntlmssp_state->crypt->ntlm2.receiving.seal_state,
495                              &recv_seal_blob);
496
497                 dump_arc4_state("NTLMSSP recv seal arc4 state:\n",
498                                 &ntlmssp_state->crypt->ntlm2.receiving.seal_state);
499
500                 /* RECV: seq num */
501                 ntlmssp_state->crypt->ntlm2.receiving.seq_num = 0;
502         } else {
503                 uint8_t weak_session_key[8];
504                 DATA_BLOB seal_session_key = ntlmssp_state->session_key;
505                 bool do_weak = false;
506
507                 DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));
508
509                 /*
510                  * Key weakening not performed on the master key for NTLM2
511                  * and does not occour for NTLM1. Therefore we only need
512                  * to do this for the LM_KEY.
513                  */
514                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_LM_KEY) {
515                         do_weak = true;
516                 }
517
518                 /*
519                  * Nothing to weaken.
520                  * We certainly don't want to 'extend' the length...
521                  */
522                 if (seal_session_key.length < 16) {
523                         /* TODO: is this really correct? */
524                         do_weak = false;
525                 }
526
527                 if (do_weak) {
528                         memcpy(weak_session_key, seal_session_key.data, 8);
529                         seal_session_key = data_blob_const(weak_session_key, 8);
530
531                         /*
532                          * LM key doesn't support 128 bit crypto, so this is
533                          * the best we can do. If you negotiate 128 bit, but
534                          * not 56, you end up with 40 bit...
535                          */
536                         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
537                                 weak_session_key[7] = 0xa0;
538                         } else { /* forty bits */
539                                 weak_session_key[5] = 0xe5;
540                                 weak_session_key[6] = 0x38;
541                                 weak_session_key[7] = 0xb0;
542                         }
543                 }
544
545                 arcfour_init(&ntlmssp_state->crypt->ntlm.seal_state,
546                              &seal_session_key);
547
548                 dump_arc4_state("NTLMv1 arc4 state:\n",
549                                 &ntlmssp_state->crypt->ntlm.seal_state);
550
551                 ntlmssp_state->crypt->ntlm.seq_num = 0;
552         }
553
554         return NT_STATUS_OK;
555 }