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s3: Fix an uninitialized variable
[Samba/ita.git] / libcli / auth / ntlmssp_sign.c
blob3cf1ed75a73b741ca0f74b79a24bf35d17f7836e
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 }