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/>.
23 #include "../libcli/auth/libcli_auth.h"
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"
31 * Some notes on then NTLM2 code:
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.
40 static void dump_arc4_state(const char *description
,
41 struct arcfour_state
*state
)
43 dump_data_pw(description
, state
->sbox
, sizeof(state
->sbox
));
46 static void calc_ntlmv2_key(uint8_t subkey
[16],
47 DATA_BLOB session_key
,
50 struct MD5Context ctx3
;
52 MD5Update(&ctx3
, session_key
.data
, session_key
.length
);
53 MD5Update(&ctx3
, (const uint8_t *)constant
, strlen(constant
)+1);
54 MD5Final(subkey
, &ctx3
);
57 enum ntlmssp_direction
{
62 static NTSTATUS
ntlmssp_make_packet_signature(struct ntlmssp_state
*ntlmssp_state
,
63 const uint8_t *data
, size_t length
,
64 const uint8_t *whole_pdu
, size_t pdu_length
,
65 enum ntlmssp_direction direction
,
66 DATA_BLOB
*sig
, bool encrypt_sig
)
68 if (ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_NTLM2
) {
73 *sig
= data_blob(NULL
, NTLMSSP_SIG_SIZE
);
75 return NT_STATUS_NO_MEMORY
;
80 DEBUG(100,("ntlmssp_make_packet_signature: SEND seq = %u, len = %u, pdu_len = %u\n",
81 ntlmssp_state
->ntlm2_send_seq_num
,
83 (unsigned int)pdu_length
));
85 SIVAL(seq_num
, 0, ntlmssp_state
->ntlm2_send_seq_num
);
86 ntlmssp_state
->ntlm2_send_seq_num
++;
87 hmac_md5_init_limK_to_64(ntlmssp_state
->send_sign_key
, 16, &ctx
);
91 DEBUG(100,("ntlmssp_make_packet_signature: RECV seq = %u, len = %u, pdu_len = %u\n",
92 ntlmssp_state
->ntlm2_recv_seq_num
,
94 (unsigned int)pdu_length
));
96 SIVAL(seq_num
, 0, ntlmssp_state
->ntlm2_recv_seq_num
);
97 ntlmssp_state
->ntlm2_recv_seq_num
++;
98 hmac_md5_init_limK_to_64(ntlmssp_state
->recv_sign_key
, 16, &ctx
);
102 dump_data_pw("pdu data ", whole_pdu
, pdu_length
);
104 hmac_md5_update(seq_num
, sizeof(seq_num
), &ctx
);
105 hmac_md5_update(whole_pdu
, pdu_length
, &ctx
);
106 hmac_md5_final(digest
, &ctx
);
108 if (encrypt_sig
&& (ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_KEY_EXCH
)) {
111 arcfour_crypt_sbox(&ntlmssp_state
->send_seal_arc4_state
, digest
, 8);
113 case NTLMSSP_RECEIVE
:
114 arcfour_crypt_sbox(&ntlmssp_state
->recv_seal_arc4_state
, digest
, 8);
119 SIVAL(sig
->data
, 0, NTLMSSP_SIGN_VERSION
);
120 memcpy(sig
->data
+ 4, digest
, 8);
121 memcpy(sig
->data
+ 12, seq_num
, 4);
123 dump_data_pw("ntlmssp v2 sig ", sig
->data
, sig
->length
);
127 crc
= crc32_calc_buffer(data
, length
);
128 if (!msrpc_gen(ntlmssp_state
, sig
, "dddd", NTLMSSP_SIGN_VERSION
, 0, crc
, ntlmssp_state
->ntlmv1_seq_num
)) {
129 return NT_STATUS_NO_MEMORY
;
132 ntlmssp_state
->ntlmv1_seq_num
++;
134 dump_arc4_state("ntlmssp hash: \n", &ntlmssp_state
->ntlmv1_arc4_state
);
135 arcfour_crypt_sbox(&ntlmssp_state
->ntlmv1_arc4_state
, sig
->data
+4, sig
->length
-4);
140 NTSTATUS
ntlmssp_sign_packet(struct ntlmssp_state
*ntlmssp_state
,
141 const uint8_t *data
, size_t length
,
142 const uint8_t *whole_pdu
, size_t pdu_length
,
147 if (!(ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_SIGN
)) {
148 DEBUG(3, ("NTLMSSP Signing not negotiated - cannot sign packet!\n"));
149 return NT_STATUS_INVALID_PARAMETER
;
152 if (!ntlmssp_state
->session_key
.length
) {
153 DEBUG(3, ("NO session key, cannot check sign packet\n"));
154 return NT_STATUS_NO_USER_SESSION_KEY
;
157 nt_status
= ntlmssp_make_packet_signature(ntlmssp_state
,
159 whole_pdu
, pdu_length
,
160 NTLMSSP_SEND
, sig
, True
);
166 * Check the signature of an incoming packet
167 * @note caller *must* check that the signature is the size it expects
171 NTSTATUS
ntlmssp_check_packet(struct ntlmssp_state
*ntlmssp_state
,
172 const uint8_t *data
, size_t length
,
173 const uint8_t *whole_pdu
, size_t pdu_length
,
174 const DATA_BLOB
*sig
)
179 if (!ntlmssp_state
->session_key
.length
) {
180 DEBUG(3, ("NO session key, cannot check packet signature\n"));
181 return NT_STATUS_NO_USER_SESSION_KEY
;
184 if (sig
->length
< 8) {
185 DEBUG(0, ("NTLMSSP packet check failed due to short signature (%lu bytes)!\n",
186 (unsigned long)sig
->length
));
189 nt_status
= ntlmssp_make_packet_signature(ntlmssp_state
,
191 whole_pdu
, pdu_length
,
192 NTLMSSP_RECEIVE
, &local_sig
, True
);
194 if (!NT_STATUS_IS_OK(nt_status
)) {
195 DEBUG(0, ("NTLMSSP packet check failed with %s\n", nt_errstr(nt_status
)));
196 data_blob_free(&local_sig
);
200 if (ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_NTLM2
) {
201 if (local_sig
.length
!= sig
->length
||
202 memcmp(local_sig
.data
, sig
->data
, sig
->length
) != 0) {
203 DEBUG(5, ("BAD SIG NTLM2: wanted signature of\n"));
204 dump_data(5, local_sig
.data
, local_sig
.length
);
206 DEBUG(5, ("BAD SIG: got signature of\n"));
207 dump_data(5, sig
->data
, sig
->length
);
209 DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n"));
210 data_blob_free(&local_sig
);
211 return NT_STATUS_ACCESS_DENIED
;
214 if (local_sig
.length
!= sig
->length
||
215 memcmp(local_sig
.data
+ 8, sig
->data
+ 8, sig
->length
- 8) != 0) {
216 DEBUG(5, ("BAD SIG NTLM1: wanted signature of\n"));
217 dump_data(5, local_sig
.data
, local_sig
.length
);
219 DEBUG(5, ("BAD SIG: got signature of\n"));
220 dump_data(5, sig
->data
, sig
->length
);
222 DEBUG(0, ("NTLMSSP NTLM1 packet check failed due to invalid signature!\n"));
223 data_blob_free(&local_sig
);
224 return NT_STATUS_ACCESS_DENIED
;
227 dump_data_pw("checked ntlmssp signature\n", sig
->data
, sig
->length
);
228 DEBUG(10,("ntlmssp_check_packet: NTLMSSP signature OK !\n"));
230 data_blob_free(&local_sig
);
235 * Seal data with the NTLMSSP algorithm
239 NTSTATUS
ntlmssp_seal_packet(struct ntlmssp_state
*ntlmssp_state
,
240 uint8_t *data
, size_t length
,
241 uint8_t *whole_pdu
, size_t pdu_length
,
244 if (!(ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_SEAL
)) {
245 DEBUG(3, ("NTLMSSP Sealing not negotiated - cannot seal packet!\n"));
246 return NT_STATUS_INVALID_PARAMETER
;
249 if (!ntlmssp_state
->session_key
.length
) {
250 DEBUG(3, ("NO session key, cannot seal packet\n"));
251 return NT_STATUS_NO_USER_SESSION_KEY
;
254 DEBUG(10,("ntlmssp_seal_data: seal\n"));
255 dump_data_pw("ntlmssp clear data\n", data
, length
);
256 if (ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_NTLM2
) {
257 /* The order of these two operations matters - we must first seal the packet,
258 then seal the sequence number - this is because the send_seal_hash is not
259 constant, but is is rather updated with each iteration */
260 NTSTATUS nt_status
= ntlmssp_make_packet_signature(ntlmssp_state
,
262 whole_pdu
, pdu_length
,
263 NTLMSSP_SEND
, sig
, False
);
264 if (!NT_STATUS_IS_OK(nt_status
)) {
268 arcfour_crypt_sbox(&ntlmssp_state
->send_seal_arc4_state
, data
, length
);
269 if (ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_KEY_EXCH
) {
270 arcfour_crypt_sbox(&ntlmssp_state
->send_seal_arc4_state
, sig
->data
+4, 8);
274 crc
= crc32_calc_buffer(data
, length
);
275 if (!msrpc_gen(ntlmssp_state
, sig
, "dddd", NTLMSSP_SIGN_VERSION
, 0, crc
, ntlmssp_state
->ntlmv1_seq_num
)) {
276 return NT_STATUS_NO_MEMORY
;
279 /* The order of these two operations matters - we must first seal the packet,
280 then seal the sequence number - this is because the ntlmv1_arc4_state is not
281 constant, but is is rather updated with each iteration */
283 dump_arc4_state("ntlmv1 arc4 state:\n",
284 &ntlmssp_state
->ntlmv1_arc4_state
);
285 arcfour_crypt_sbox(&ntlmssp_state
->ntlmv1_arc4_state
, data
, length
);
287 dump_arc4_state("ntlmv1 arc4 state:\n",
288 &ntlmssp_state
->ntlmv1_arc4_state
);
290 arcfour_crypt_sbox(&ntlmssp_state
->ntlmv1_arc4_state
, sig
->data
+4, sig
->length
-4);
292 ntlmssp_state
->ntlmv1_seq_num
++;
294 dump_data_pw("ntlmssp signature\n", sig
->data
, sig
->length
);
295 dump_data_pw("ntlmssp sealed data\n", data
, length
);
301 * Unseal data with the NTLMSSP algorithm
305 NTSTATUS
ntlmssp_unseal_packet(struct ntlmssp_state
*ntlmssp_state
,
306 uint8_t *data
, size_t length
,
307 uint8_t *whole_pdu
, size_t pdu_length
,
310 if (!ntlmssp_state
->session_key
.length
) {
311 DEBUG(3, ("NO session key, cannot unseal packet\n"));
312 return NT_STATUS_NO_USER_SESSION_KEY
;
315 DEBUG(10,("ntlmssp_unseal_packet: seal\n"));
316 dump_data_pw("ntlmssp sealed data\n", data
, length
);
318 if (ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_NTLM2
) {
319 /* First unseal the data. */
320 arcfour_crypt_sbox(&ntlmssp_state
->recv_seal_arc4_state
, data
, length
);
321 dump_data_pw("ntlmv2 clear data\n", data
, length
);
323 arcfour_crypt_sbox(&ntlmssp_state
->ntlmv1_arc4_state
, data
, length
);
324 dump_data_pw("ntlmv1 clear data\n", data
, length
);
326 return ntlmssp_check_packet(ntlmssp_state
, data
, length
, whole_pdu
, pdu_length
, sig
);
330 Initialise the state for NTLMSSP signing.
332 NTSTATUS
ntlmssp_sign_init(struct ntlmssp_state
*ntlmssp_state
)
336 mem_ctx
= talloc_init("weak_keys");
338 return NT_STATUS_NO_MEMORY
;
341 DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
342 debug_ntlmssp_flags(ntlmssp_state
->neg_flags
);
344 if (ntlmssp_state
->session_key
.length
< 8) {
345 TALLOC_FREE(mem_ctx
);
346 DEBUG(3, ("NO session key, cannot intialise signing\n"));
347 return NT_STATUS_NO_USER_SESSION_KEY
;
350 if (ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_NTLM2
) {
351 DATA_BLOB weak_session_key
= ntlmssp_state
->session_key
;
352 const char *send_sign_const
;
353 const char *send_seal_const
;
354 const char *recv_sign_const
;
355 const char *recv_seal_const
;
356 uint8_t send_seal_key
[16];
357 DATA_BLOB send_seal_blob
= data_blob_const(send_seal_key
,
358 sizeof(send_seal_key
));
359 uint8_t recv_seal_key
[16];
360 DATA_BLOB recv_seal_blob
= data_blob_const(recv_seal_key
,
361 sizeof(recv_seal_key
));
363 switch (ntlmssp_state
->role
) {
365 send_sign_const
= CLI_SIGN
;
366 send_seal_const
= CLI_SEAL
;
367 recv_sign_const
= SRV_SIGN
;
368 recv_seal_const
= SRV_SEAL
;
371 send_sign_const
= SRV_SIGN
;
372 send_seal_const
= SRV_SEAL
;
373 recv_sign_const
= CLI_SIGN
;
374 recv_seal_const
= CLI_SEAL
;
377 TALLOC_FREE(mem_ctx
);
378 return NT_STATUS_INTERNAL_ERROR
;
382 Weaken NTLMSSP keys to cope with down-level clients, servers and export restrictions.
383 We probably should have some parameters to control this, once we get NTLM2 working.
386 if (ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_128
) {
388 } else if (ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_56
) {
389 weak_session_key
.length
= 7;
390 } else { /* forty bits */
391 weak_session_key
.length
= 5;
394 dump_data_pw("NTLMSSP weakend master key:\n",
395 weak_session_key
.data
,
396 weak_session_key
.length
);
399 calc_ntlmv2_key(ntlmssp_state
->send_sign_key
,
400 ntlmssp_state
->session_key
, send_sign_const
);
401 dump_data_pw("NTLMSSP send sign key:\n",
402 ntlmssp_state
->send_sign_key
, 16);
404 /* SEND: seal ARCFOUR pad */
405 calc_ntlmv2_key(send_seal_key
,
406 weak_session_key
, send_seal_const
);
407 dump_data_pw("NTLMSSP send seal key:\n", send_seal_key
, 16);
409 arcfour_init(&ntlmssp_state
->send_seal_arc4_state
,
412 dump_arc4_state("NTLMSSP send seal arc4 state:\n",
413 &ntlmssp_state
->send_seal_arc4_state
);
416 calc_ntlmv2_key(ntlmssp_state
->recv_sign_key
,
417 ntlmssp_state
->session_key
, recv_sign_const
);
418 dump_data_pw("NTLMSSP recv send sign key:\n",
419 ntlmssp_state
->recv_sign_key
, 16);
421 /* RECV: seal ARCFOUR pad */
422 calc_ntlmv2_key(recv_seal_key
,
423 weak_session_key
, recv_seal_const
);
424 dump_data_pw("NTLMSSP recv seal key:\n", recv_seal_key
, 16);
426 arcfour_init(&ntlmssp_state
->recv_seal_arc4_state
,
429 dump_arc4_state("NTLMSSP recv seal arc4 state:\n",
430 &ntlmssp_state
->recv_seal_arc4_state
);
432 ntlmssp_state
->ntlm2_send_seq_num
= 0;
433 ntlmssp_state
->ntlm2_recv_seq_num
= 0;
438 /* Hmmm. Shouldn't we also weaken keys for ntlmv1 ? JRA. */
440 DATA_BLOB weak_session_key
= ntlmssp_state
->session_key
;
442 Weaken NTLMSSP keys to cope with down-level clients, servers and export restrictions.
443 We probably should have some parameters to control this, once we get NTLM2 working.
446 if (ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_128
) {
448 } else if (ntlmssp_state
->neg_flags
& NTLMSSP_NEGOTIATE_56
) {
449 weak_session_key
.length
= 6;
450 } else { /* forty bits */
451 weak_session_key
.length
= 5;
453 dump_data_pw("NTLMSSP weakend master key:\n",
454 weak_session_key
.data
,
455 weak_session_key
.length
);
458 DATA_BLOB weak_session_key
= ntlmssp_weaken_keys(ntlmssp_state
, mem_ctx
);
460 DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));
462 arcfour_init(&ntlmssp_state
->ntlmv1_arc4_state
,
465 dump_arc4_state("NTLMv1 arc4 state:\n",
466 &ntlmssp_state
->ntlmv1_arc4_state
);
468 ntlmssp_state
->ntlmv1_seq_num
= 0;
471 TALLOC_FREE(mem_ctx
);