Fix typo in comments.
[ira/wip.git] / source3 / libsmb / 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 "ntlmssp.h"
23 #include "../libcli/auth/libcli_auth.h"
24
25 #define CLI_SIGN "session key to client-to-server signing key magic constant"
26 #define CLI_SEAL "session key to client-to-server sealing key magic constant"
27 #define SRV_SIGN "session key to server-to-client signing key magic constant"
28 #define SRV_SEAL "session key to server-to-client sealing key magic constant"
29
30 /**
31  * Some notes on then NTLM2 code:
32  *
33  * NTLM2 is a AEAD system.  This means that the data encrypted is not
34  * all the data that is signed.  In DCE-RPC case, the headers of the
35  * DCE-RPC packets are also signed.  This prevents some of the
36  * fun-and-games one might have by changing them.
37  *
38  */
39
40 static void dump_arc4_state(const char *description,
41                             struct arcfour_state *state)
42 {
43         dump_data_pw(description, state->sbox, sizeof(state->sbox));
44 }
45
46 static void calc_ntlmv2_key(unsigned char subkey[16],
47                                 DATA_BLOB session_key,
48                                 const char *constant)
49 {
50         struct MD5Context ctx3;
51         MD5Init(&ctx3);
52         MD5Update(&ctx3, session_key.data, session_key.length);
53         MD5Update(&ctx3, (const unsigned char *)constant, strlen(constant)+1);
54         MD5Final(subkey, &ctx3);
55 }
56
57 enum ntlmssp_direction {
58         NTLMSSP_SEND,
59         NTLMSSP_RECEIVE
60 };
61
62 static NTSTATUS ntlmssp_make_packet_signature(struct ntlmssp_state *ntlmssp_state,
63                                                 const uchar *data, size_t length,
64                                                 const uchar *whole_pdu, size_t pdu_length,
65                                                 enum ntlmssp_direction direction,
66                                                 DATA_BLOB *sig,
67                                                 bool encrypt_sig)
68 {
69         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
70                 HMACMD5Context ctx;
71                 uchar seq_num[4];
72                 uchar digest[16];
73
74                 *sig = data_blob(NULL, NTLMSSP_SIG_SIZE);
75                 if (!sig->data) {
76                         return NT_STATUS_NO_MEMORY;
77                 }
78
79                 switch (direction) {
80                 case NTLMSSP_SEND:
81                         DEBUG(100,("ntlmssp_make_packet_signature: SEND seq = %u, len = %u, pdu_len = %u\n",
82                                 ntlmssp_state->ntlm2_send_seq_num,
83                                 (unsigned int)length,
84                                 (unsigned int)pdu_length));
85
86                         SIVAL(seq_num, 0, ntlmssp_state->ntlm2_send_seq_num);
87                         ntlmssp_state->ntlm2_send_seq_num++;
88                         hmac_md5_init_limK_to_64(ntlmssp_state->send_sign_key, 16, &ctx);
89                         break;
90                 case NTLMSSP_RECEIVE:
91
92                         DEBUG(100,("ntlmssp_make_packet_signature: RECV seq = %u, len = %u, pdu_len = %u\n",
93                                 ntlmssp_state->ntlm2_recv_seq_num,
94                                 (unsigned int)length,
95                                 (unsigned int)pdu_length));
96
97                         SIVAL(seq_num, 0, ntlmssp_state->ntlm2_recv_seq_num);
98                         ntlmssp_state->ntlm2_recv_seq_num++;
99                         hmac_md5_init_limK_to_64(ntlmssp_state->recv_sign_key, 16, &ctx);
100                         break;
101                 }
102
103                 dump_data_pw("pdu data ", whole_pdu, pdu_length);
104
105                 hmac_md5_update(seq_num, 4, &ctx);
106                 hmac_md5_update(whole_pdu, pdu_length, &ctx);
107                 hmac_md5_final(digest, &ctx);
108
109                 if (encrypt_sig && (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH)) {
110                         switch (direction) {
111                         case NTLMSSP_SEND:
112                                 arcfour_crypt_sbox(&ntlmssp_state->send_seal_arc4_state, digest, 8);
113                                 break;
114                         case NTLMSSP_RECEIVE:
115                                 arcfour_crypt_sbox(&ntlmssp_state->recv_seal_arc4_state, digest, 8);
116                                 break;
117                         }
118                 }
119
120                 SIVAL(sig->data, 0, NTLMSSP_SIGN_VERSION);
121                 memcpy(sig->data + 4, digest, 8);
122                 memcpy(sig->data + 12, seq_num, 4);
123
124                 dump_data_pw("ntlmssp v2 sig ", sig->data, sig->length);
125
126         } else {
127                 uint32 crc;
128                 crc = crc32_calc_buffer(data, length);
129                 if (!msrpc_gen(ntlmssp_state, sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmv1_seq_num)) {
130                         return NT_STATUS_NO_MEMORY;
131                 }
132
133                 ntlmssp_state->ntlmv1_seq_num++;
134
135                 dump_arc4_state("ntlmssp hash: \n", &ntlmssp_state->ntlmv1_arc4_state);
136                 arcfour_crypt_sbox(&ntlmssp_state->ntlmv1_arc4_state, sig->data+4, sig->length-4);
137         }
138         return NT_STATUS_OK;
139 }
140
141 NTSTATUS ntlmssp_sign_packet(struct ntlmssp_state *ntlmssp_state,
142                                     const uchar *data, size_t length,
143                                     const uchar *whole_pdu, size_t pdu_length,
144                                     DATA_BLOB *sig)
145 {
146         NTSTATUS nt_status;
147
148         if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN)) {
149                 DEBUG(3, ("NTLMSSP Signing not negotiated - cannot sign packet!\n"));
150                 return NT_STATUS_INVALID_PARAMETER;
151         }
152
153         if (!ntlmssp_state->session_key.length) {
154                 DEBUG(3, ("NO session key, cannot check sign packet\n"));
155                 return NT_STATUS_NO_USER_SESSION_KEY;
156         }
157
158         nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
159                                                 data, length,
160                                                 whole_pdu, pdu_length,
161                                                 NTLMSSP_SEND, sig, True);
162
163         return nt_status;
164 }
165
166 /**
167  * Check the signature of an incoming packet
168  * @note caller *must* check that the signature is the size it expects
169  *
170  */
171
172 NTSTATUS ntlmssp_check_packet(struct ntlmssp_state *ntlmssp_state,
173                                 const uchar *data, size_t length,
174                                 const uchar *whole_pdu, size_t pdu_length,
175                                 const DATA_BLOB *sig)
176 {
177         DATA_BLOB local_sig;
178         NTSTATUS nt_status;
179
180         if (!ntlmssp_state->session_key.length) {
181                 DEBUG(3, ("NO session key, cannot check packet signature\n"));
182                 return NT_STATUS_NO_USER_SESSION_KEY;
183         }
184
185         if (sig->length < 8) {
186                 DEBUG(0, ("NTLMSSP packet check failed due to short signature (%lu bytes)!\n",
187                           (unsigned long)sig->length));
188         }
189
190         nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
191                                                 data, length,
192                                                 whole_pdu, pdu_length,
193                                                 NTLMSSP_RECEIVE, &local_sig, True);
194
195         if (!NT_STATUS_IS_OK(nt_status)) {
196                 DEBUG(0, ("NTLMSSP packet check failed with %s\n", nt_errstr(nt_status)));
197                 data_blob_free(&local_sig);
198                 return nt_status;
199         }
200
201         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
202                 if (local_sig.length != sig->length ||
203                                 memcmp(local_sig.data, sig->data, sig->length) != 0) {
204                         DEBUG(5, ("BAD SIG NTLM2: wanted signature of\n"));
205                         dump_data(5, local_sig.data, local_sig.length);
206
207                         DEBUG(5, ("BAD SIG: got signature of\n"));
208                         dump_data(5, sig->data, sig->length);
209
210                         DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n"));
211                         data_blob_free(&local_sig);
212                         return NT_STATUS_ACCESS_DENIED;
213                 }
214         } else {
215                 if (local_sig.length != sig->length ||
216                                 memcmp(local_sig.data + 8, sig->data + 8, sig->length - 8) != 0) {
217                         DEBUG(5, ("BAD SIG NTLM1: wanted signature of\n"));
218                         dump_data(5, local_sig.data, local_sig.length);
219
220                         DEBUG(5, ("BAD SIG: got signature of\n"));
221                         dump_data(5, sig->data, sig->length);
222
223                         DEBUG(0, ("NTLMSSP NTLM1 packet check failed due to invalid signature!\n"));
224                         data_blob_free(&local_sig);
225                         return NT_STATUS_ACCESS_DENIED;
226                 }
227         }
228         dump_data_pw("checked ntlmssp signature\n", sig->data, sig->length);
229         DEBUG(10,("ntlmssp_check_packet: NTLMSSP signature OK !\n"));
230
231         data_blob_free(&local_sig);
232         return NT_STATUS_OK;
233 }
234
235 /**
236  * Seal data with the NTLMSSP algorithm
237  *
238  */
239
240 NTSTATUS ntlmssp_seal_packet(struct ntlmssp_state *ntlmssp_state,
241                              uchar *data, size_t length,
242                              uchar *whole_pdu, size_t pdu_length,
243                              DATA_BLOB *sig)
244 {
245         if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL)) {
246                 DEBUG(3, ("NTLMSSP Sealing not negotiated - cannot seal packet!\n"));
247                 return NT_STATUS_INVALID_PARAMETER;
248         }
249
250         if (!ntlmssp_state->session_key.length) {
251                 DEBUG(3, ("NO session key, cannot seal packet\n"));
252                 return NT_STATUS_NO_USER_SESSION_KEY;
253         }
254
255         DEBUG(10,("ntlmssp_seal_data: seal\n"));
256         dump_data_pw("ntlmssp clear data\n", data, length);
257         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
258                 /* The order of these two operations matters - we must first seal the packet,
259                    then seal the sequence number - this is because the send_seal_hash is not
260                    constant, but is is rather updated with each iteration */
261                 NTSTATUS nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
262                                                         data, length,
263                                                         whole_pdu, pdu_length,
264                                                         NTLMSSP_SEND, sig, False);
265                 if (!NT_STATUS_IS_OK(nt_status)) {
266                         return nt_status;
267                 }
268
269                 arcfour_crypt_sbox(&ntlmssp_state->send_seal_arc4_state, data, length);
270                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
271                         arcfour_crypt_sbox(&ntlmssp_state->send_seal_arc4_state, sig->data+4, 8);
272                 }
273         } else {
274                 uint32 crc;
275                 crc = crc32_calc_buffer(data, length);
276                 if (!msrpc_gen(ntlmssp_state, sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmv1_seq_num)) {
277                         return NT_STATUS_NO_MEMORY;
278                 }
279
280                 /* The order of these two operations matters - we must first seal the packet,
281                    then seal the sequence number - this is because the ntlmv1_arc4_state is not
282                    constant, but is is rather updated with each iteration */
283
284                 dump_arc4_state("ntlmv1 arc4 state:\n",
285                                                 &ntlmssp_state->ntlmv1_arc4_state);
286                 arcfour_crypt_sbox(&ntlmssp_state->ntlmv1_arc4_state, data, length);
287
288                 dump_arc4_state("ntlmv1 arc4 state:\n",
289                                                 &ntlmssp_state->ntlmv1_arc4_state);
290
291                 arcfour_crypt_sbox(&ntlmssp_state->ntlmv1_arc4_state, sig->data+4, sig->length-4);
292
293                 ntlmssp_state->ntlmv1_seq_num++;
294         }
295         dump_data_pw("ntlmssp signature\n", sig->data, sig->length);
296         dump_data_pw("ntlmssp sealed data\n", data, length);
297
298         return NT_STATUS_OK;
299 }
300
301 /**
302  * Unseal data with the NTLMSSP algorithm
303  *
304  */
305
306 NTSTATUS ntlmssp_unseal_packet(struct ntlmssp_state *ntlmssp_state,
307                                 uchar *data, size_t length,
308                                 uchar *whole_pdu, size_t pdu_length,
309                                 DATA_BLOB *sig)
310 {
311         if (!ntlmssp_state->session_key.length) {
312                 DEBUG(3, ("NO session key, cannot unseal packet\n"));
313                 return NT_STATUS_NO_USER_SESSION_KEY;
314         }
315
316         DEBUG(10,("ntlmssp_unseal_packet: seal\n"));
317         dump_data_pw("ntlmssp sealed data\n", data, length);
318
319         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
320                 /* First unseal the data. */
321                 arcfour_crypt_sbox(&ntlmssp_state->recv_seal_arc4_state, data, length);
322                 dump_data_pw("ntlmv2 clear data\n", data, length);
323         } else {
324                 arcfour_crypt_sbox(&ntlmssp_state->ntlmv1_arc4_state, data, length);
325                 dump_data_pw("ntlmv1 clear data\n", data, length);
326         }
327         return ntlmssp_check_packet(ntlmssp_state, data, length, whole_pdu, pdu_length, sig);
328 }
329
330 /**
331    Initialise the state for NTLMSSP signing.
332 */
333 NTSTATUS ntlmssp_sign_init(struct ntlmssp_state *ntlmssp_state)
334 {
335         TALLOC_CTX *mem_ctx;
336
337         mem_ctx = talloc_init("weak_keys");
338         if (!mem_ctx) {
339                 return NT_STATUS_NO_MEMORY;
340         }
341
342         DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
343         debug_ntlmssp_flags(ntlmssp_state->neg_flags);
344
345         if (ntlmssp_state->session_key.length < 8) {
346                 TALLOC_FREE(mem_ctx);
347                 DEBUG(3, ("NO session key, cannot intialise signing\n"));
348                 return NT_STATUS_NO_USER_SESSION_KEY;
349         }
350
351         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
352                 DATA_BLOB weak_session_key = ntlmssp_state->session_key;
353                 const char *send_sign_const;
354                 const char *send_seal_const;
355                 const char *recv_sign_const;
356                 const char *recv_seal_const;
357                 DATA_BLOB send_seal_key_blob, recv_seal_blob;
358
359                 switch (ntlmssp_state->role) {
360                 case NTLMSSP_CLIENT:
361                         send_sign_const = CLI_SIGN;
362                         send_seal_const = CLI_SEAL;
363                         recv_sign_const = SRV_SIGN;
364                         recv_seal_const = SRV_SEAL;
365                         break;
366                 case NTLMSSP_SERVER:
367                         send_sign_const = SRV_SIGN;
368                         send_seal_const = SRV_SEAL;
369                         recv_sign_const = CLI_SIGN;
370                         recv_seal_const = CLI_SEAL;
371                         break;
372                 default:
373                         TALLOC_FREE(mem_ctx);
374                         return NT_STATUS_INTERNAL_ERROR;
375                 }
376
377                 /**
378                   Weaken NTLMSSP keys to cope with down-level clients, servers and export restrictions.
379                   We probably should have some parameters to control this, once we get NTLM2 working.
380                 */
381
382                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
383                         ;
384                 } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
385                         weak_session_key.length = 7;
386                 } else { /* forty bits */
387                         weak_session_key.length = 5;
388                 }
389
390                 dump_data_pw("NTLMSSP weakend master key:\n",
391                                 weak_session_key.data,
392                                 weak_session_key.length);
393
394                 /* SEND: sign key */
395                 calc_ntlmv2_key(ntlmssp_state->send_sign_key,
396                                 ntlmssp_state->session_key, send_sign_const);
397                 dump_data_pw("NTLMSSP send sign key:\n",
398                                 ntlmssp_state->send_sign_key, 16);
399
400                 /* SEND: seal ARCFOUR pad */
401                 calc_ntlmv2_key(ntlmssp_state->send_seal_key,
402                                 weak_session_key, send_seal_const);
403                 dump_data_pw("NTLMSSP send seal key:\n",
404                                 ntlmssp_state->send_seal_key, 16);
405
406                 send_seal_key_blob.data = ntlmssp_state->send_seal_key;
407                 send_seal_key_blob.length = 16;
408                 arcfour_init(&ntlmssp_state->send_seal_arc4_state,
409                              &send_seal_key_blob);
410
411                 dump_arc4_state("NTLMSSP send seal arc4 state:\n",
412                              &ntlmssp_state->send_seal_arc4_state);
413
414                 /* RECV: sign key */
415                 calc_ntlmv2_key(ntlmssp_state->recv_sign_key,
416                                 ntlmssp_state->session_key, recv_sign_const);
417                 dump_data_pw("NTLMSSP recv send sign key:\n",
418                                 ntlmssp_state->recv_sign_key, 16);
419
420                 /* RECV: seal ARCFOUR pad */
421                 calc_ntlmv2_key(ntlmssp_state->recv_seal_key,
422                                 weak_session_key, recv_seal_const);
423
424                 dump_data_pw("NTLMSSP recv seal key:\n",
425                                 ntlmssp_state->recv_seal_key, 16);
426
427                 recv_seal_blob.data = ntlmssp_state->recv_seal_key;
428                 recv_seal_blob.length = 16;
429                 arcfour_init(&ntlmssp_state->recv_seal_arc4_state,
430                                 &recv_seal_blob);
431
432                 dump_arc4_state("NTLMSSP recv seal arc4 state:\n",
433                              &ntlmssp_state->recv_seal_arc4_state);
434
435                 ntlmssp_state->ntlm2_send_seq_num = 0;
436                 ntlmssp_state->ntlm2_recv_seq_num = 0;
437
438
439         } else {
440 #if 0
441                 /* Hmmm. Shouldn't we also weaken keys for ntlmv1 ? JRA. */
442
443                 DATA_BLOB weak_session_key = ntlmssp_state->session_key;
444                 /**
445                   Weaken NTLMSSP keys to cope with down-level clients, servers and export restrictions.
446                   We probably should have some parameters to control this, once we get NTLM2 working.
447                 */
448
449                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
450                         ;
451                 } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
452                         weak_session_key.length = 6;
453                 } else { /* forty bits */
454                         weak_session_key.length = 5;
455                 }
456                 dump_data_pw("NTLMSSP weakend master key:\n",
457                                 weak_session_key.data,
458                                 weak_session_key.length);
459 #endif
460
461                 DATA_BLOB weak_session_key = ntlmssp_weaken_keys(ntlmssp_state, mem_ctx);
462
463                 DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));
464
465                 arcfour_init(&ntlmssp_state->ntlmv1_arc4_state,
466                              &weak_session_key);
467
468                 dump_arc4_state("NTLMv1 arc4 state:\n",
469                                 &ntlmssp_state->ntlmv1_arc4_state);
470
471                 ntlmssp_state->ntlmv1_seq_num = 0;
472         }
473
474         TALLOC_FREE(mem_ctx);
475         return NT_STATUS_OK;
476 }