2 * Unix SMB/CIFS implementation.
4 * NTLMSSP Signing routines
5 * Copyright (C) Andrew Bartlett 2003-2005
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.
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.
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/>.
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"
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"
35 * Some notes on the NTLM2 code:
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.
44 static void dump_arc4_state(const char *description,
45 struct arcfour_state *state)
47 dump_data_pw(description, state->sbox, sizeof(state->sbox));
50 static void calc_ntlmv2_key(uint8_t subkey[16],
51 DATA_BLOB session_key,
54 struct MD5Context ctx3;
56 MD5Update(&ctx3, session_key.data, session_key.length);
57 MD5Update(&ctx3, (const uint8_t *)constant, strlen(constant)+1);
58 MD5Final(subkey, &ctx3);
61 enum ntlmssp_direction {
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)
73 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
78 *sig = data_blob_talloc(sig_mem_ctx, NULL, NTLMSSP_SIG_SIZE);
80 return NT_STATUS_NO_MEMORY;
85 DEBUG(100,("ntlmssp_make_packet_signature: SEND seq = %u, len = %u, pdu_len = %u\n",
86 ntlmssp_state->crypt->ntlm2.sending.seq_num,
88 (unsigned int)pdu_length));
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);
96 DEBUG(100,("ntlmssp_make_packet_signature: RECV seq = %u, len = %u, pdu_len = %u\n",
97 ntlmssp_state->crypt->ntlm2.receiving.seq_num,
99 (unsigned int)pdu_length));
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);
107 dump_data_pw("pdu data ", whole_pdu, pdu_length);
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);
113 if (encrypt_sig && (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH)) {
116 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
119 case NTLMSSP_RECEIVE:
120 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.receiving.seal_state,
126 SIVAL(sig->data, 0, NTLMSSP_SIGN_VERSION);
127 memcpy(sig->data + 4, digest, 8);
128 memcpy(sig->data + 12, seq_num, 4);
130 dump_data_pw("ntlmssp v2 sig ", sig->data, sig->length);
136 crc = crc32_calc_buffer(data, length);
138 ok = msrpc_gen(sig_mem_ctx,
140 NTLMSSP_SIGN_VERSION, 0, crc,
141 ntlmssp_state->crypt->ntlm.seq_num);
143 return NT_STATUS_NO_MEMORY;
146 ntlmssp_state->crypt->ntlm.seq_num++;
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);
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,
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;
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;
174 nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
177 whole_pdu, pdu_length,
178 NTLMSSP_SEND, sig, true);
184 * Check the signature of an incoming packet
185 * @note caller *must* check that the signature is the size it expects
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)
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;
203 if (sig->length < 8) {
204 DEBUG(0, ("NTLMSSP packet check failed due to short signature (%lu bytes)!\n",
205 (unsigned long)sig->length));
208 tmp_ctx = talloc_new(ntlmssp_state);
210 return NT_STATUS_NO_MEMORY;
213 nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
216 whole_pdu, pdu_length,
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);
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);
233 DEBUG(5, ("BAD SIG: got signature of\n"));
234 dump_data(5, sig->data, sig->length);
236 DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n"));
237 talloc_free(tmp_ctx);
238 return NT_STATUS_ACCESS_DENIED;
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);
246 DEBUG(5, ("BAD SIG: got signature of\n"));
247 dump_data(5, sig->data, sig->length);
249 DEBUG(0, ("NTLMSSP NTLM1 packet check failed due to invalid signature!\n"));
250 talloc_free(tmp_ctx);
251 return NT_STATUS_ACCESS_DENIED;
254 dump_data_pw("checked ntlmssp signature\n", sig->data, sig->length);
255 DEBUG(10,("ntlmssp_check_packet: NTLMSSP signature OK !\n"));
257 talloc_free(tmp_ctx);
262 * Seal data with the NTLMSSP algorithm
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,
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;
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;
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) {
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
293 nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
296 whole_pdu, pdu_length,
299 if (!NT_STATUS_IS_OK(nt_status)) {
303 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
305 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
306 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
313 crc = crc32_calc_buffer(data, length);
315 ok = msrpc_gen(sig_mem_ctx,
317 NTLMSSP_SIGN_VERSION, 0, crc,
318 ntlmssp_state->crypt->ntlm.seq_num);
320 return NT_STATUS_NO_MEMORY;
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
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,
336 dump_arc4_state("ntlmv1 arc4 state:\n",
337 &ntlmssp_state->crypt->ntlm.seal_state);
339 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
340 sig->data+4, sig->length-4);
342 ntlmssp_state->crypt->ntlm.seq_num++;
344 dump_data_pw("ntlmssp signature\n", sig->data, sig->length);
345 dump_data_pw("ntlmssp sealed data\n", data, length);
351 * Unseal data with the NTLMSSP algorithm
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)
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;
366 DEBUG(10,("ntlmssp_unseal_packet: seal\n"));
367 dump_data_pw("ntlmssp sealed data\n", data, length);
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,
373 dump_data_pw("ntlmv2 clear data\n", data, length);
375 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
377 dump_data_pw("ntlmv1 clear data\n", data, length);
379 status = ntlmssp_check_packet(ntlmssp_state,
381 whole_pdu, pdu_length,
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));
392 Initialise the state for NTLMSSP signing.
394 NTSTATUS ntlmssp_sign_init(struct ntlmssp_state *ntlmssp_state)
396 DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
397 debug_ntlmssp_flags(ntlmssp_state->neg_flags);
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;
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;
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));
423 switch (ntlmssp_state->role) {
425 send_sign_const = CLI_SIGN;
426 send_seal_const = CLI_SEAL;
427 recv_sign_const = SRV_SIGN;
428 recv_seal_const = SRV_SEAL;
431 send_sign_const = SRV_SIGN;
432 send_seal_const = SRV_SEAL;
433 recv_sign_const = CLI_SIGN;
434 recv_seal_const = CLI_SEAL;
437 return NT_STATUS_INTERNAL_ERROR;
441 * Weaken NTLMSSP keys to cope with down-level
442 * clients, servers and export restrictions.
444 * We probably should have some parameters to
445 * control this, once we get NTLM2 working.
447 * Key weakening was not performed on the master key
448 * for NTLM2, but must be done on the encryption subkeys only.
451 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
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;
459 dump_data_pw("NTLMSSP weakend master key:\n",
460 weak_session_key.data,
461 weak_session_key.length);
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);
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);
474 arcfour_init(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
477 dump_arc4_state("NTLMSSP send seal arc4 state:\n",
478 &ntlmssp_state->crypt->ntlm2.sending.seal_state);
481 ntlmssp_state->crypt->ntlm2.sending.seq_num = 0;
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);
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);
494 arcfour_init(&ntlmssp_state->crypt->ntlm2.receiving.seal_state,
497 dump_arc4_state("NTLMSSP recv seal arc4 state:\n",
498 &ntlmssp_state->crypt->ntlm2.receiving.seal_state);
501 ntlmssp_state->crypt->ntlm2.receiving.seq_num = 0;
503 uint8_t weak_session_key[8];
504 DATA_BLOB seal_session_key = ntlmssp_state->session_key;
505 bool do_weak = false;
507 DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));
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.
514 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_LM_KEY) {
520 * We certainly don't want to 'extend' the length...
522 if (seal_session_key.length < 16) {
523 /* TODO: is this really correct? */
528 memcpy(weak_session_key, seal_session_key.data, 8);
529 seal_session_key = data_blob_const(weak_session_key, 8);
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...
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;
545 arcfour_init(&ntlmssp_state->crypt->ntlm.seal_state,
548 dump_arc4_state("NTLMv1 arc4 state:\n",
549 &ntlmssp_state->crypt->ntlm.seal_state);
551 ntlmssp_state->crypt->ntlm.seq_num = 0;