Merge branch 'master' of ssh://git.samba.org/data/git/samba into arc4
[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
23 #define CLI_SIGN "session key to client-to-server signing key magic constant"
24 #define CLI_SEAL "session key to client-to-server sealing key magic constant"
25 #define SRV_SIGN "session key to server-to-client signing key magic constant"
26 #define SRV_SEAL "session key to server-to-client sealing key magic constant"
27
28 /**
29  * Some notes on then NTLM2 code:
30  *
31  * NTLM2 is a AEAD system.  This means that the data encrypted is not
32  * all the data that is signed.  In DCE-RPC case, the headers of the
33  * DCE-RPC packets are also signed.  This prevents some of the
34  * fun-and-games one might have by changing them.
35  *
36  */
37
38 static void calc_ntlmv2_key(unsigned char subkey[16],
39                                 DATA_BLOB session_key,
40                                 const char *constant)
41 {
42         struct MD5Context ctx3;
43         MD5Init(&ctx3);
44         MD5Update(&ctx3, session_key.data, session_key.length);
45         MD5Update(&ctx3, (const unsigned char *)constant, strlen(constant)+1);
46         MD5Final(subkey, &ctx3);
47 }
48
49 enum ntlmssp_direction {
50         NTLMSSP_SEND,
51         NTLMSSP_RECEIVE
52 };
53
54 static NTSTATUS ntlmssp_make_packet_signature(NTLMSSP_STATE *ntlmssp_state,
55                                                 const uchar *data, size_t length, 
56                                                 const uchar *whole_pdu, size_t pdu_length,
57                                                 enum ntlmssp_direction direction,
58                                                 DATA_BLOB *sig,
59                                                 bool encrypt_sig)
60 {
61         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
62                 HMACMD5Context ctx;
63                 uchar seq_num[4];
64                 uchar digest[16];
65
66                 *sig = data_blob(NULL, NTLMSSP_SIG_SIZE);
67                 if (!sig->data) {
68                         return NT_STATUS_NO_MEMORY;
69                 }
70
71                 switch (direction) {
72                         case NTLMSSP_SEND:
73                                 DEBUG(100,("ntlmssp_make_packet_signature: SEND seq = %u, len = %u, pdu_len = %u\n",
74                                         ntlmssp_state->ntlm2_send_seq_num,
75                                         (unsigned int)length,
76                                         (unsigned int)pdu_length));
77
78                                 SIVAL(seq_num, 0, ntlmssp_state->ntlm2_send_seq_num);
79                                 ntlmssp_state->ntlm2_send_seq_num++;
80                                 hmac_md5_init_limK_to_64(ntlmssp_state->send_sign_key, 16, &ctx);
81                                 break;
82                         case NTLMSSP_RECEIVE:
83
84                                 DEBUG(100,("ntlmssp_make_packet_signature: RECV seq = %u, len = %u, pdu_len = %u\n",
85                                         ntlmssp_state->ntlm2_recv_seq_num,
86                                         (unsigned int)length,
87                                         (unsigned int)pdu_length));
88
89                                 SIVAL(seq_num, 0, ntlmssp_state->ntlm2_recv_seq_num);
90                                 ntlmssp_state->ntlm2_recv_seq_num++;
91                                 hmac_md5_init_limK_to_64(ntlmssp_state->recv_sign_key, 16, &ctx);
92                                 break;
93                 }
94
95                 dump_data_pw("pdu data ", whole_pdu, pdu_length);
96
97                 hmac_md5_update(seq_num, 4, &ctx);
98                 hmac_md5_update(whole_pdu, pdu_length, &ctx);
99                 hmac_md5_final(digest, &ctx);
100
101                 if (encrypt_sig && (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH)) {
102                         switch (direction) {
103                         case NTLMSSP_SEND:
104                                 arcfour_crypt_sbox(&ntlmssp_state->send_seal_arc4_state, digest, 8);
105                                 break;
106                         case NTLMSSP_RECEIVE:
107                                 arcfour_crypt_sbox(&ntlmssp_state->recv_seal_arc4_state, digest, 8);
108                                 break;
109                         }
110                 }
111
112                 SIVAL(sig->data, 0, NTLMSSP_SIGN_VERSION);
113                 memcpy(sig->data + 4, digest, 8);
114                 memcpy(sig->data + 12, seq_num, 4);
115
116                 dump_data_pw("ntlmssp v2 sig ", sig->data, sig->length);
117
118         } else {
119                 uint32 crc;
120                 crc = crc32_calc_buffer(data, length);
121                 if (!msrpc_gen(sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmv1_seq_num)) {
122                         return NT_STATUS_NO_MEMORY;
123                 }
124                 
125                 ntlmssp_state->ntlmv1_seq_num++;
126
127                 dump_data_pw("ntlmssp hash:\n", ntlmssp_state->ntlmv1_arc4_state,
128                              sizeof(ntlmssp_state->ntlmv1_arc4_state));
129                 arcfour_crypt_sbox(&ntlmssp_state->ntlmv1_arc4_state, sig->data+4, sig->length-4);
130         }
131         return NT_STATUS_OK;
132 }
133
134 NTSTATUS ntlmssp_sign_packet(NTLMSSP_STATE *ntlmssp_state,
135                                     const uchar *data, size_t length, 
136                                     const uchar *whole_pdu, size_t pdu_length, 
137                                     DATA_BLOB *sig) 
138 {
139         NTSTATUS nt_status;
140
141         if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN)) {
142                 DEBUG(3, ("NTLMSSP Signing not negotiated - cannot sign packet!\n"));
143                 return NT_STATUS_INVALID_PARAMETER;
144         }
145
146         if (!ntlmssp_state->session_key.length) {
147                 DEBUG(3, ("NO session key, cannot check sign packet\n"));
148                 return NT_STATUS_NO_USER_SESSION_KEY;
149         }
150
151         nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
152                                                 data, length,
153                                                 whole_pdu, pdu_length,
154                                                 NTLMSSP_SEND, sig, True);
155
156         return nt_status;
157 }
158
159 /**
160  * Check the signature of an incoming packet 
161  * @note caller *must* check that the signature is the size it expects 
162  *
163  */
164
165 NTSTATUS ntlmssp_check_packet(NTLMSSP_STATE *ntlmssp_state,
166                                 const uchar *data, size_t length, 
167                                 const uchar *whole_pdu, size_t pdu_length, 
168                                 const DATA_BLOB *sig) 
169 {
170         DATA_BLOB local_sig;
171         NTSTATUS nt_status;
172
173         if (!ntlmssp_state->session_key.length) {
174                 DEBUG(3, ("NO session key, cannot check packet signature\n"));
175                 return NT_STATUS_NO_USER_SESSION_KEY;
176         }
177
178         if (sig->length < 8) {
179                 DEBUG(0, ("NTLMSSP packet check failed due to short signature (%lu bytes)!\n", 
180                           (unsigned long)sig->length));
181         }
182
183         nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
184                                                 data, length,
185                                                 whole_pdu, pdu_length,
186                                                 NTLMSSP_RECEIVE, &local_sig, True);
187         
188         if (!NT_STATUS_IS_OK(nt_status)) {
189                 DEBUG(0, ("NTLMSSP packet check failed with %s\n", nt_errstr(nt_status)));
190                 data_blob_free(&local_sig);
191                 return nt_status;
192         }
193         
194         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
195                 if (local_sig.length != sig->length ||
196                                 memcmp(local_sig.data, sig->data, sig->length) != 0) {
197                         DEBUG(5, ("BAD SIG NTLM2: wanted signature of\n"));
198                         dump_data(5, local_sig.data, local_sig.length);
199
200                         DEBUG(5, ("BAD SIG: got signature of\n"));
201                         dump_data(5, sig->data, sig->length);
202
203                         DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n"));
204                         data_blob_free(&local_sig);
205                         return NT_STATUS_ACCESS_DENIED;
206                 }
207         } else {
208                 if (local_sig.length != sig->length ||
209                                 memcmp(local_sig.data + 8, sig->data + 8, sig->length - 8) != 0) {
210                         DEBUG(5, ("BAD SIG NTLM1: wanted signature of\n"));
211                         dump_data(5, local_sig.data, local_sig.length);
212
213                         DEBUG(5, ("BAD SIG: got signature of\n"));
214                         dump_data(5, sig->data, sig->length);
215
216                         DEBUG(0, ("NTLMSSP NTLM1 packet check failed due to invalid signature!\n"));
217                         data_blob_free(&local_sig);
218                         return NT_STATUS_ACCESS_DENIED;
219                 }
220         }
221         dump_data_pw("checked ntlmssp signature\n", sig->data, sig->length);
222         DEBUG(10,("ntlmssp_check_packet: NTLMSSP signature OK !\n"));
223
224         data_blob_free(&local_sig);
225         return NT_STATUS_OK;
226 }
227
228 /**
229  * Seal data with the NTLMSSP algorithm
230  *
231  */
232
233 NTSTATUS ntlmssp_seal_packet(NTLMSSP_STATE *ntlmssp_state,
234                              uchar *data, size_t length,
235                              uchar *whole_pdu, size_t pdu_length,
236                              DATA_BLOB *sig)
237 {       
238         if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL)) {
239                 DEBUG(3, ("NTLMSSP Sealing not negotiated - cannot seal packet!\n"));
240                 return NT_STATUS_INVALID_PARAMETER;
241         }
242
243         if (!ntlmssp_state->session_key.length) {
244                 DEBUG(3, ("NO session key, cannot seal packet\n"));
245                 return NT_STATUS_NO_USER_SESSION_KEY;
246         }
247
248         DEBUG(10,("ntlmssp_seal_data: seal\n"));
249         dump_data_pw("ntlmssp clear data\n", data, length);
250         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
251                 /* The order of these two operations matters - we must first seal the packet,
252                    then seal the sequence number - this is becouse the send_seal_hash is not
253                    constant, but is is rather updated with each iteration */
254                 NTSTATUS nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
255                                                         data, length,
256                                                         whole_pdu, pdu_length,
257                                                         NTLMSSP_SEND, sig, False);
258                 if (!NT_STATUS_IS_OK(nt_status)) {
259                         return nt_status;
260                 }
261
262                 arcfour_crypt_sbox(&ntlmssp_state->send_seal_arc4_state, data, length);
263                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
264                         arcfour_crypt_sbox(&ntlmssp_state->send_seal_arc4_state, sig->data+4, 8);
265                 }
266         } else {
267                 uint32 crc;
268                 crc = crc32_calc_buffer(data, length);
269                 if (!msrpc_gen(sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmv1_seq_num)) {
270                         return NT_STATUS_NO_MEMORY;
271                 }
272
273                 /* The order of these two operations matters - we must first seal the packet,
274                    then seal the sequence number - this is becouse the ntlmv1_arc4_state is not
275                    constant, but is is rather updated with each iteration */
276                 
277                 dump_data_pw("ntlmv1 arc4 state:\n", ntlmssp_state->ntlmv1_arc4_state,
278                              sizeof(ntlmssp_state->ntlmv1_arc4_state));
279                 arcfour_crypt_sbox(&ntlmssp_state->ntlmv1_arc4_state, data, length);
280
281                 dump_data_pw("ntlmv1 arc4 state:\n", ntlmssp_state->ntlmv1_arc4_state,
282                              sizeof(ntlmssp_state->ntlmv1_arc4_state));
283
284                 arcfour_crypt_sbox(&ntlmssp_state->ntlmv1_arc4_state, sig->data+4, sig->length-4);
285
286                 ntlmssp_state->ntlmv1_seq_num++;
287         }
288         dump_data_pw("ntlmssp signature\n", sig->data, sig->length);
289         dump_data_pw("ntlmssp sealed data\n", data, length);
290
291         return NT_STATUS_OK;
292 }
293
294 /**
295  * Unseal data with the NTLMSSP algorithm
296  *
297  */
298
299 NTSTATUS ntlmssp_unseal_packet(NTLMSSP_STATE *ntlmssp_state,
300                                 uchar *data, size_t length,
301                                 uchar *whole_pdu, size_t pdu_length,
302                                 DATA_BLOB *sig)
303 {
304         if (!ntlmssp_state->session_key.length) {
305                 DEBUG(3, ("NO session key, cannot unseal packet\n"));
306                 return NT_STATUS_NO_USER_SESSION_KEY;
307         }
308
309         DEBUG(10,("ntlmssp_unseal_packet: seal\n"));
310         dump_data_pw("ntlmssp sealed data\n", data, length);
311
312         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
313                 /* First unseal the data. */
314                 arcfour_crypt_sbox(&ntlmssp_state->recv_seal_arc4_state, data, length);
315                 dump_data_pw("ntlmv2 clear data\n", data, length);
316         } else {
317                 arcfour_crypt_sbox(&ntlmssp_state->ntlmv1_arc4_state, data, length);
318                 dump_data_pw("ntlmv1 clear data\n", data, length);
319         }
320         return ntlmssp_check_packet(ntlmssp_state, data, length, whole_pdu, pdu_length, sig);
321 }
322
323 /**
324    Initialise the state for NTLMSSP signing.
325 */
326 NTSTATUS ntlmssp_sign_init(NTLMSSP_STATE *ntlmssp_state)
327 {
328         unsigned char p24[24];
329         TALLOC_CTX *mem_ctx;
330         ZERO_STRUCT(p24);
331
332         mem_ctx = talloc_init("weak_keys");
333         if (!mem_ctx) {
334                 return NT_STATUS_NO_MEMORY;
335         }
336
337         DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
338         debug_ntlmssp_flags(ntlmssp_state->neg_flags);
339
340         if (ntlmssp_state->session_key.length < 8) {
341                 TALLOC_FREE(mem_ctx);
342                 DEBUG(3, ("NO session key, cannot intialise signing\n"));
343                 return NT_STATUS_NO_USER_SESSION_KEY;
344         }
345
346         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
347                 DATA_BLOB weak_session_key = ntlmssp_state->session_key;
348                 const char *send_sign_const;
349                 const char *send_seal_const;
350                 const char *recv_sign_const;
351                 const char *recv_seal_const;
352
353                 switch (ntlmssp_state->role) {
354                 case NTLMSSP_CLIENT:
355                         send_sign_const = CLI_SIGN;
356                         send_seal_const = CLI_SEAL;
357                         recv_sign_const = SRV_SIGN;
358                         recv_seal_const = SRV_SEAL;
359                         break;
360                 case NTLMSSP_SERVER:
361                         send_sign_const = SRV_SIGN;
362                         send_seal_const = SRV_SEAL;
363                         recv_sign_const = CLI_SIGN;
364                         recv_seal_const = CLI_SEAL;
365                         break;
366                 default:
367                         TALLOC_FREE(mem_ctx);
368                         return NT_STATUS_INTERNAL_ERROR;
369                 }
370
371                 /**
372                   Weaken NTLMSSP keys to cope with down-level clients, servers and export restrictions.
373                   We probably should have some parameters to control this, once we get NTLM2 working.
374                 */
375
376                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
377                         ;
378                 } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
379                         weak_session_key.length = 7;
380                 } else { /* forty bits */
381                         weak_session_key.length = 5;
382                 }
383
384                 dump_data_pw("NTLMSSP weakend master key:\n",
385                                 weak_session_key.data,
386                                 weak_session_key.length);
387
388                 /* SEND: sign key */
389                 calc_ntlmv2_key(ntlmssp_state->send_sign_key,
390                                 ntlmssp_state->session_key, send_sign_const);
391                 dump_data_pw("NTLMSSP send sign key:\n",
392                                 ntlmssp_state->send_sign_key, 16);
393
394                 /* SEND: seal ARCFOUR pad */
395                 calc_ntlmv2_key(ntlmssp_state->send_seal_key,
396                                 weak_session_key, send_seal_const);
397                 dump_data_pw("NTLMSSP send seal key:\n",
398                                 ntlmssp_state->send_seal_key, 16);
399
400                 arcfour_init(&ntlmssp_state->send_seal_arc4_state,
401                                 ntlmssp_state->send_seal_key, 16);
402
403                 dump_data_pw("NTLMSSP send seal arc4 state:\n", 
404                              ntlmssp_state->send_seal_arc4_state, 
405                              sizeof(ntlmssp_state->send_seal_arc4_state));
406
407                 /* RECV: sign key */
408                 calc_ntlmv2_key(ntlmssp_state->recv_sign_key,
409                                 ntlmssp_state->session_key, recv_sign_const);
410                 dump_data_pw("NTLMSSP recv send sign key:\n",
411                                 ntlmssp_state->recv_sign_key, 16);
412
413                 /* RECV: seal ARCFOUR pad */
414                 calc_ntlmv2_key(ntlmssp_state->recv_seal_key,
415                                 weak_session_key, recv_seal_const);
416                 
417                 dump_data_pw("NTLMSSP recv seal key:\n",
418                                 ntlmssp_state->recv_seal_key, 16);
419                                 
420                 arcfour_init(&ntlmssp_state->recv_seal_arc4_state,
421                                 ntlmssp_state->recv_seal_key, 16);
422
423                 dump_data_pw("NTLMSSP recv seal arc4 state:\n", 
424                              ntlmssp_state->recv_seal_arc4_state, 
425                              sizeof(ntlmssp_state->recv_seal_arc4_state));
426
427                 ntlmssp_state->ntlm2_send_seq_num = 0;
428                 ntlmssp_state->ntlm2_recv_seq_num = 0;
429
430
431         } else {
432 #if 0
433                 /* Hmmm. Shouldn't we also weaken keys for ntlmv1 ? JRA. */
434
435                 DATA_BLOB weak_session_key = ntlmssp_state->session_key;
436                 /**
437                   Weaken NTLMSSP keys to cope with down-level clients, servers and export restrictions.
438                   We probably should have some parameters to control this, once we get NTLM2 working.
439                 */
440
441                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
442                         ;
443                 } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
444                         weak_session_key.length = 6;
445                 } else { /* forty bits */
446                         weak_session_key.length = 5;
447                 }
448                 dump_data_pw("NTLMSSP weakend master key:\n",
449                                 weak_session_key.data,
450                                 weak_session_key.length);
451 #endif
452
453                 DATA_BLOB weak_session_key = ntlmssp_weaken_keys(ntlmssp_state, mem_ctx);
454
455                 DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));
456
457                 arcfour_init(&ntlmssp_state->ntlmv1_arc4_state,
458                              weak_session_key.data, weak_session_key.length);
459
460                 dump_data_pw("NTLMv1 arc4 state:\n", ntlmssp_state->ntlmv1_arc4_state,
461                                 sizeof(ntlmssp_state->ntlmv1_arc4_state));
462
463                 ntlmssp_state->ntlmv1_seq_num = 0;
464         }
465
466         TALLOC_FREE(mem_ctx);
467         return NT_STATUS_OK;
468 }