source: branches/samba-3.5.x/source3/libsmb/ntlmssp_sign.c

Last change on this file was 414, checked in by Herwig Bauernfeind, 15 years ago

Samba 3.5.0: Initial import
File size: 14.4 KB
Line 
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/libcli_auth.h"
23
24#define CLI_SIGN "session key to client-to-server signing key magic constant"
25#define CLI_SEAL "session key to client-to-server sealing key magic constant"
26#define SRV_SIGN "session key to server-to-client signing key magic constant"
27#define SRV_SEAL "session key to server-to-client sealing key magic constant"
28
29/**
30 * Some notes on then NTLM2 code:
31 *
32 * NTLM2 is a AEAD system. This means that the data encrypted is not
33 * all the data that is signed. In DCE-RPC case, the headers of the
34 * DCE-RPC packets are also signed. This prevents some of the
35 * fun-and-games one might have by changing them.
36 *
37 */
38
39static void dump_arc4_state(const char *description,
40 struct arcfour_state *state)
41{
42 dump_data_pw(description, state->sbox, sizeof(state->sbox));
43}
44
45static void calc_ntlmv2_key(unsigned char subkey[16],
46 DATA_BLOB session_key,
47 const char *constant)
48{
49 struct MD5Context ctx3;
50 MD5Init(&ctx3);
51 MD5Update(&ctx3, session_key.data, session_key.length);
52 MD5Update(&ctx3, (const unsigned char *)constant, strlen(constant)+1);
53 MD5Final(subkey, &ctx3);
54}
55
56enum ntlmssp_direction {
57 NTLMSSP_SEND,
58 NTLMSSP_RECEIVE
59};
60
61static NTSTATUS ntlmssp_make_packet_signature(NTLMSSP_STATE *ntlmssp_state,
62 const uchar *data, size_t length,
63 const uchar *whole_pdu, size_t pdu_length,
64 enum ntlmssp_direction direction,
65 DATA_BLOB *sig,
66 bool encrypt_sig)
67{
68 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
69 HMACMD5Context ctx;
70 uchar seq_num[4];
71 uchar digest[16];
72
73 *sig = data_blob(NULL, NTLMSSP_SIG_SIZE);
74 if (!sig->data) {
75 return NT_STATUS_NO_MEMORY;
76 }
77
78 switch (direction) {
79 case NTLMSSP_SEND:
80 DEBUG(100,("ntlmssp_make_packet_signature: SEND seq = %u, len = %u, pdu_len = %u\n",
81 ntlmssp_state->ntlm2_send_seq_num,
82 (unsigned int)length,
83 (unsigned int)pdu_length));
84
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);
88 break;
89 case NTLMSSP_RECEIVE:
90
91 DEBUG(100,("ntlmssp_make_packet_signature: RECV seq = %u, len = %u, pdu_len = %u\n",
92 ntlmssp_state->ntlm2_recv_seq_num,
93 (unsigned int)length,
94 (unsigned int)pdu_length));
95
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);
99 break;
100 }
101
102 dump_data_pw("pdu data ", whole_pdu, pdu_length);
103
104 hmac_md5_update(seq_num, 4, &ctx);
105 hmac_md5_update(whole_pdu, pdu_length, &ctx);
106 hmac_md5_final(digest, &ctx);
107
108 if (encrypt_sig && (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH)) {
109 switch (direction) {
110 case NTLMSSP_SEND:
111 arcfour_crypt_sbox(&ntlmssp_state->send_seal_arc4_state, digest, 8);
112 break;
113 case NTLMSSP_RECEIVE:
114 arcfour_crypt_sbox(&ntlmssp_state->recv_seal_arc4_state, digest, 8);
115 break;
116 }
117 }
118
119 SIVAL(sig->data, 0, NTLMSSP_SIGN_VERSION);
120 memcpy(sig->data + 4, digest, 8);
121 memcpy(sig->data + 12, seq_num, 4);
122
123 dump_data_pw("ntlmssp v2 sig ", sig->data, sig->length);
124
125 } else {
126 uint32 crc;
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;
130 }
131
132 ntlmssp_state->ntlmv1_seq_num++;
133
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);
136 }
137 return NT_STATUS_OK;
138}
139
140NTSTATUS ntlmssp_sign_packet(NTLMSSP_STATE *ntlmssp_state,
141 const uchar *data, size_t length,
142 const uchar *whole_pdu, size_t pdu_length,
143 DATA_BLOB *sig)
144{
145 NTSTATUS nt_status;
146
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;
150 }
151
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;
155 }
156
157 nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
158 data, length,
159 whole_pdu, pdu_length,
160 NTLMSSP_SEND, sig, True);
161
162 return nt_status;
163}
164
165/**
166 * Check the signature of an incoming packet
167 * @note caller *must* check that the signature is the size it expects
168 *
169 */
170
171NTSTATUS ntlmssp_check_packet(NTLMSSP_STATE *ntlmssp_state,
172 const uchar *data, size_t length,
173 const uchar *whole_pdu, size_t pdu_length,
174 const DATA_BLOB *sig)
175{
176 DATA_BLOB local_sig;
177 NTSTATUS nt_status;
178
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;
182 }
183
184 if (sig->length < 8) {
185 DEBUG(0, ("NTLMSSP packet check failed due to short signature (%lu bytes)!\n",
186 (unsigned long)sig->length));
187 }
188
189 nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
190 data, length,
191 whole_pdu, pdu_length,
192 NTLMSSP_RECEIVE, &local_sig, True);
193
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);
197 return nt_status;
198 }
199
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);
205
206 DEBUG(5, ("BAD SIG: got signature of\n"));
207 dump_data(5, sig->data, sig->length);
208
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;
212 }
213 } else {
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);
218
219 DEBUG(5, ("BAD SIG: got signature of\n"));
220 dump_data(5, sig->data, sig->length);
221
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;
225 }
226 }
227 dump_data_pw("checked ntlmssp signature\n", sig->data, sig->length);
228 DEBUG(10,("ntlmssp_check_packet: NTLMSSP signature OK !\n"));
229
230 data_blob_free(&local_sig);
231 return NT_STATUS_OK;
232}
233
234/**
235 * Seal data with the NTLMSSP algorithm
236 *
237 */
238
239NTSTATUS ntlmssp_seal_packet(NTLMSSP_STATE *ntlmssp_state,
240 uchar *data, size_t length,
241 uchar *whole_pdu, size_t pdu_length,
242 DATA_BLOB *sig)
243{
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;
247 }
248
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;
252 }
253
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 becouse 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,
261 data, length,
262 whole_pdu, pdu_length,
263 NTLMSSP_SEND, sig, False);
264 if (!NT_STATUS_IS_OK(nt_status)) {
265 return nt_status;
266 }
267
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);
271 }
272 } else {
273 uint32 crc;
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;
277 }
278
279 /* The order of these two operations matters - we must first seal the packet,
280 then seal the sequence number - this is becouse the ntlmv1_arc4_state is not
281 constant, but is is rather updated with each iteration */
282
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);
286
287 dump_arc4_state("ntlmv1 arc4 state:\n",
288 &ntlmssp_state->ntlmv1_arc4_state);
289
290 arcfour_crypt_sbox(&ntlmssp_state->ntlmv1_arc4_state, sig->data+4, sig->length-4);
291
292 ntlmssp_state->ntlmv1_seq_num++;
293 }
294 dump_data_pw("ntlmssp signature\n", sig->data, sig->length);
295 dump_data_pw("ntlmssp sealed data\n", data, length);
296
297 return NT_STATUS_OK;
298}
299
300/**
301 * Unseal data with the NTLMSSP algorithm
302 *
303 */
304
305NTSTATUS ntlmssp_unseal_packet(NTLMSSP_STATE *ntlmssp_state,
306 uchar *data, size_t length,
307 uchar *whole_pdu, size_t pdu_length,
308 DATA_BLOB *sig)
309{
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;
313 }
314
315 DEBUG(10,("ntlmssp_unseal_packet: seal\n"));
316 dump_data_pw("ntlmssp sealed data\n", data, length);
317
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);
322 } else {
323 arcfour_crypt_sbox(&ntlmssp_state->ntlmv1_arc4_state, data, length);
324 dump_data_pw("ntlmv1 clear data\n", data, length);
325 }
326 return ntlmssp_check_packet(ntlmssp_state, data, length, whole_pdu, pdu_length, sig);
327}
328
329/**
330 Initialise the state for NTLMSSP signing.
331*/
332NTSTATUS ntlmssp_sign_init(NTLMSSP_STATE *ntlmssp_state)
333{
334 unsigned char p24[24];
335 TALLOC_CTX *mem_ctx;
336 ZERO_STRUCT(p24);
337
338 mem_ctx = talloc_init("weak_keys");
339 if (!mem_ctx) {
340 return NT_STATUS_NO_MEMORY;
341 }
342
343 DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
344 debug_ntlmssp_flags(ntlmssp_state->neg_flags);
345
346 if (ntlmssp_state->session_key.length < 8) {
347 TALLOC_FREE(mem_ctx);
348 DEBUG(3, ("NO session key, cannot intialise signing\n"));
349 return NT_STATUS_NO_USER_SESSION_KEY;
350 }
351
352 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
353 DATA_BLOB weak_session_key = ntlmssp_state->session_key;
354 const char *send_sign_const;
355 const char *send_seal_const;
356 const char *recv_sign_const;
357 const char *recv_seal_const;
358 DATA_BLOB send_seal_key_blob, recv_seal_blob;
359
360 switch (ntlmssp_state->role) {
361 case NTLMSSP_CLIENT:
362 send_sign_const = CLI_SIGN;
363 send_seal_const = CLI_SEAL;
364 recv_sign_const = SRV_SIGN;
365 recv_seal_const = SRV_SEAL;
366 break;
367 case NTLMSSP_SERVER:
368 send_sign_const = SRV_SIGN;
369 send_seal_const = SRV_SEAL;
370 recv_sign_const = CLI_SIGN;
371 recv_seal_const = CLI_SEAL;
372 break;
373 default:
374 TALLOC_FREE(mem_ctx);
375 return NT_STATUS_INTERNAL_ERROR;
376 }
377
378 /**
379 Weaken NTLMSSP keys to cope with down-level clients, servers and export restrictions.
380 We probably should have some parameters to control this, once we get NTLM2 working.
381 */
382
383 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
384 ;
385 } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
386 weak_session_key.length = 7;
387 } else { /* forty bits */
388 weak_session_key.length = 5;
389 }
390
391 dump_data_pw("NTLMSSP weakend master key:\n",
392 weak_session_key.data,
393 weak_session_key.length);
394
395 /* SEND: sign key */
396 calc_ntlmv2_key(ntlmssp_state->send_sign_key,
397 ntlmssp_state->session_key, send_sign_const);
398 dump_data_pw("NTLMSSP send sign key:\n",
399 ntlmssp_state->send_sign_key, 16);
400
401 /* SEND: seal ARCFOUR pad */
402 calc_ntlmv2_key(ntlmssp_state->send_seal_key,
403 weak_session_key, send_seal_const);
404 dump_data_pw("NTLMSSP send seal key:\n",
405 ntlmssp_state->send_seal_key, 16);
406
407 send_seal_key_blob.data = ntlmssp_state->send_seal_key;
408 send_seal_key_blob.length = 16;
409 arcfour_init(&ntlmssp_state->send_seal_arc4_state,
410 &send_seal_key_blob);
411
412 dump_arc4_state("NTLMSSP send seal arc4 state:\n",
413 &ntlmssp_state->send_seal_arc4_state);
414
415 /* RECV: sign key */
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);
420
421 /* RECV: seal ARCFOUR pad */
422 calc_ntlmv2_key(ntlmssp_state->recv_seal_key,
423 weak_session_key, recv_seal_const);
424
425 dump_data_pw("NTLMSSP recv seal key:\n",
426 ntlmssp_state->recv_seal_key, 16);
427
428 recv_seal_blob.data = ntlmssp_state->recv_seal_key;
429 recv_seal_blob.length = 16;
430 arcfour_init(&ntlmssp_state->recv_seal_arc4_state,
431 &recv_seal_blob);
432
433 dump_arc4_state("NTLMSSP recv seal arc4 state:\n",
434 &ntlmssp_state->recv_seal_arc4_state);
435
436 ntlmssp_state->ntlm2_send_seq_num = 0;
437 ntlmssp_state->ntlm2_recv_seq_num = 0;
438
439
440 } else {
441#if 0
442 /* Hmmm. Shouldn't we also weaken keys for ntlmv1 ? JRA. */
443
444 DATA_BLOB weak_session_key = ntlmssp_state->session_key;
445 /**
446 Weaken NTLMSSP keys to cope with down-level clients, servers and export restrictions.
447 We probably should have some parameters to control this, once we get NTLM2 working.
448 */
449
450 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
451 ;
452 } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
453 weak_session_key.length = 6;
454 } else { /* forty bits */
455 weak_session_key.length = 5;
456 }
457 dump_data_pw("NTLMSSP weakend master key:\n",
458 weak_session_key.data,
459 weak_session_key.length);
460#endif
461
462 DATA_BLOB weak_session_key = ntlmssp_weaken_keys(ntlmssp_state, mem_ctx);
463
464 DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));
465
466 arcfour_init(&ntlmssp_state->ntlmv1_arc4_state,
467 &weak_session_key);
468
469 dump_arc4_state("NTLMv1 arc4 state:\n",
470 &ntlmssp_state->ntlmv1_arc4_state);
471
472 ntlmssp_state->ntlmv1_seq_num = 0;
473 }
474
475 TALLOC_FREE(mem_ctx);
476 return NT_STATUS_OK;
477}
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