source: trunk-3.0/source/libsmb/ntlmssp_sign.c@ 103

Last change on this file since 103 was 1, checked in by Paul Smedley, 19 years ago

Initial code 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 2 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, write to the Free Software Foundation,
19 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20 */
21
22#include "includes.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 calc_ntlmv2_key(unsigned char subkey[16],
40 DATA_BLOB session_key,
41 const char *constant)
42{
43 struct MD5Context ctx3;
44 MD5Init(&ctx3);
45 MD5Update(&ctx3, session_key.data, session_key.length);
46 MD5Update(&ctx3, (const unsigned char *)constant, strlen(constant)+1);
47 MD5Final(subkey, &ctx3);
48}
49
50enum ntlmssp_direction {
51 NTLMSSP_SEND,
52 NTLMSSP_RECEIVE
53};
54
55static NTSTATUS ntlmssp_make_packet_signature(NTLMSSP_STATE *ntlmssp_state,
56 const uchar *data, size_t length,
57 const uchar *whole_pdu, size_t pdu_length,
58 enum ntlmssp_direction direction,
59 DATA_BLOB *sig,
60 BOOL encrypt_sig)
61{
62 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
63 HMACMD5Context ctx;
64 uchar seq_num[4];
65 uchar digest[16];
66
67 *sig = data_blob(NULL, NTLMSSP_SIG_SIZE);
68 if (!sig->data) {
69 return NT_STATUS_NO_MEMORY;
70 }
71
72 switch (direction) {
73 case NTLMSSP_SEND:
74 DEBUG(100,("ntlmssp_make_packet_signature: SEND seq = %u, len = %u, pdu_len = %u\n",
75 ntlmssp_state->ntlm2_send_seq_num,
76 (unsigned int)length,
77 (unsigned int)pdu_length));
78
79 SIVAL(seq_num, 0, ntlmssp_state->ntlm2_send_seq_num);
80 ntlmssp_state->ntlm2_send_seq_num++;
81 hmac_md5_init_limK_to_64(ntlmssp_state->send_sign_key, 16, &ctx);
82 break;
83 case NTLMSSP_RECEIVE:
84
85 DEBUG(100,("ntlmssp_make_packet_signature: RECV seq = %u, len = %u, pdu_len = %u\n",
86 ntlmssp_state->ntlm2_recv_seq_num,
87 (unsigned int)length,
88 (unsigned int)pdu_length));
89
90 SIVAL(seq_num, 0, ntlmssp_state->ntlm2_recv_seq_num);
91 ntlmssp_state->ntlm2_recv_seq_num++;
92 hmac_md5_init_limK_to_64(ntlmssp_state->recv_sign_key, 16, &ctx);
93 break;
94 }
95
96 dump_data_pw("pdu data ", whole_pdu, pdu_length);
97
98 hmac_md5_update(seq_num, 4, &ctx);
99 hmac_md5_update(whole_pdu, pdu_length, &ctx);
100 hmac_md5_final(digest, &ctx);
101
102 if (encrypt_sig && (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH)) {
103 switch (direction) {
104 case NTLMSSP_SEND:
105 smb_arc4_crypt(ntlmssp_state->send_seal_arc4_state, digest, 8);
106 break;
107 case NTLMSSP_RECEIVE:
108 smb_arc4_crypt(ntlmssp_state->recv_seal_arc4_state, digest, 8);
109 break;
110 }
111 }
112
113 SIVAL(sig->data, 0, NTLMSSP_SIGN_VERSION);
114 memcpy(sig->data + 4, digest, 8);
115 memcpy(sig->data + 12, seq_num, 4);
116
117 dump_data_pw("ntlmssp v2 sig ", sig->data, sig->length);
118
119 } else {
120 uint32 crc;
121 crc = crc32_calc_buffer((const char *)data, length);
122 if (!msrpc_gen(sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmv1_seq_num)) {
123 return NT_STATUS_NO_MEMORY;
124 }
125
126 ntlmssp_state->ntlmv1_seq_num++;
127
128 dump_data_pw("ntlmssp hash:\n", ntlmssp_state->ntlmv1_arc4_state,
129 sizeof(ntlmssp_state->ntlmv1_arc4_state));
130 smb_arc4_crypt(ntlmssp_state->ntlmv1_arc4_state, sig->data+4, sig->length-4);
131 }
132 return NT_STATUS_OK;
133}
134
135NTSTATUS ntlmssp_sign_packet(NTLMSSP_STATE *ntlmssp_state,
136 const uchar *data, size_t length,
137 const uchar *whole_pdu, size_t pdu_length,
138 DATA_BLOB *sig)
139{
140 NTSTATUS nt_status;
141
142 if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN)) {
143 DEBUG(3, ("NTLMSSP Signing not negotiated - cannot sign packet!\n"));
144 return NT_STATUS_INVALID_PARAMETER;
145 }
146
147 if (!ntlmssp_state->session_key.length) {
148 DEBUG(3, ("NO session key, cannot check sign packet\n"));
149 return NT_STATUS_NO_USER_SESSION_KEY;
150 }
151
152 nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
153 data, length,
154 whole_pdu, pdu_length,
155 NTLMSSP_SEND, sig, True);
156
157 return nt_status;
158}
159
160/**
161 * Check the signature of an incoming packet
162 * @note caller *must* check that the signature is the size it expects
163 *
164 */
165
166NTSTATUS ntlmssp_check_packet(NTLMSSP_STATE *ntlmssp_state,
167 const uchar *data, size_t length,
168 const uchar *whole_pdu, size_t pdu_length,
169 const DATA_BLOB *sig)
170{
171 DATA_BLOB local_sig;
172 NTSTATUS nt_status;
173
174 if (!ntlmssp_state->session_key.length) {
175 DEBUG(3, ("NO session key, cannot check packet signature\n"));
176 return NT_STATUS_NO_USER_SESSION_KEY;
177 }
178
179 if (sig->length < 8) {
180 DEBUG(0, ("NTLMSSP packet check failed due to short signature (%lu bytes)!\n",
181 (unsigned long)sig->length));
182 }
183
184 nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
185 data, length,
186 whole_pdu, pdu_length,
187 NTLMSSP_RECEIVE, &local_sig, True);
188
189 if (!NT_STATUS_IS_OK(nt_status)) {
190 DEBUG(0, ("NTLMSSP packet check failed with %s\n", nt_errstr(nt_status)));
191 data_blob_free(&local_sig);
192 return nt_status;
193 }
194
195 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
196 if (local_sig.length != sig->length ||
197 memcmp(local_sig.data, sig->data, sig->length) != 0) {
198 DEBUG(5, ("BAD SIG NTLM2: wanted signature of\n"));
199 dump_data(5, (const char *)local_sig.data, local_sig.length);
200
201 DEBUG(5, ("BAD SIG: got signature of\n"));
202 dump_data(5, (const char *)sig->data, sig->length);
203
204 DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n"));
205 data_blob_free(&local_sig);
206 return NT_STATUS_ACCESS_DENIED;
207 }
208 } else {
209 if (local_sig.length != sig->length ||
210 memcmp(local_sig.data + 8, sig->data + 8, sig->length - 8) != 0) {
211 DEBUG(5, ("BAD SIG NTLM1: wanted signature of\n"));
212 dump_data(5, (const char *)local_sig.data, local_sig.length);
213
214 DEBUG(5, ("BAD SIG: got signature of\n"));
215 dump_data(5, (const char *)sig->data, sig->length);
216
217 DEBUG(0, ("NTLMSSP NTLM1 packet check failed due to invalid signature!\n"));
218 data_blob_free(&local_sig);
219 return NT_STATUS_ACCESS_DENIED;
220 }
221 }
222 dump_data_pw("checked ntlmssp signature\n", sig->data, sig->length);
223 DEBUG(10,("ntlmssp_check_packet: NTLMSSP signature OK !\n"));
224
225 data_blob_free(&local_sig);
226 return NT_STATUS_OK;
227}
228
229/**
230 * Seal data with the NTLMSSP algorithm
231 *
232 */
233
234NTSTATUS ntlmssp_seal_packet(NTLMSSP_STATE *ntlmssp_state,
235 uchar *data, size_t length,
236 uchar *whole_pdu, size_t pdu_length,
237 DATA_BLOB *sig)
238{
239 if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL)) {
240 DEBUG(3, ("NTLMSSP Sealing not negotiated - cannot seal packet!\n"));
241 return NT_STATUS_INVALID_PARAMETER;
242 }
243
244 if (!ntlmssp_state->session_key.length) {
245 DEBUG(3, ("NO session key, cannot seal packet\n"));
246 return NT_STATUS_NO_USER_SESSION_KEY;
247 }
248
249 DEBUG(10,("ntlmssp_seal_data: seal\n"));
250 dump_data_pw("ntlmssp clear data\n", data, length);
251 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
252 /* The order of these two operations matters - we must first seal the packet,
253 then seal the sequence number - this is becouse the send_seal_hash is not
254 constant, but is is rather updated with each iteration */
255 NTSTATUS nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
256 data, length,
257 whole_pdu, pdu_length,
258 NTLMSSP_SEND, sig, False);
259 if (!NT_STATUS_IS_OK(nt_status)) {
260 return nt_status;
261 }
262
263 smb_arc4_crypt(ntlmssp_state->send_seal_arc4_state, data, length);
264 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
265 smb_arc4_crypt(ntlmssp_state->send_seal_arc4_state, sig->data+4, 8);
266 }
267 } else {
268 uint32 crc;
269 crc = crc32_calc_buffer((const char *)data, length);
270 if (!msrpc_gen(sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmv1_seq_num)) {
271 return NT_STATUS_NO_MEMORY;
272 }
273
274 /* The order of these two operations matters - we must first seal the packet,
275 then seal the sequence number - this is becouse the ntlmv1_arc4_state is not
276 constant, but is is rather updated with each iteration */
277
278 dump_data_pw("ntlmv1 arc4 state:\n", ntlmssp_state->ntlmv1_arc4_state,
279 sizeof(ntlmssp_state->ntlmv1_arc4_state));
280 smb_arc4_crypt(ntlmssp_state->ntlmv1_arc4_state, data, length);
281
282 dump_data_pw("ntlmv1 arc4 state:\n", ntlmssp_state->ntlmv1_arc4_state,
283 sizeof(ntlmssp_state->ntlmv1_arc4_state));
284
285 smb_arc4_crypt(ntlmssp_state->ntlmv1_arc4_state, sig->data+4, sig->length-4);
286
287 ntlmssp_state->ntlmv1_seq_num++;
288 }
289 dump_data_pw("ntlmssp signature\n", sig->data, sig->length);
290 dump_data_pw("ntlmssp sealed data\n", data, length);
291
292 return NT_STATUS_OK;
293}
294
295/**
296 * Unseal data with the NTLMSSP algorithm
297 *
298 */
299
300NTSTATUS ntlmssp_unseal_packet(NTLMSSP_STATE *ntlmssp_state,
301 uchar *data, size_t length,
302 uchar *whole_pdu, size_t pdu_length,
303 DATA_BLOB *sig)
304{
305 if (!ntlmssp_state->session_key.length) {
306 DEBUG(3, ("NO session key, cannot unseal packet\n"));
307 return NT_STATUS_NO_USER_SESSION_KEY;
308 }
309
310 DEBUG(10,("ntlmssp_unseal_packet: seal\n"));
311 dump_data_pw("ntlmssp sealed data\n", data, length);
312
313 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
314 /* First unseal the data. */
315 smb_arc4_crypt(ntlmssp_state->recv_seal_arc4_state, data, length);
316 dump_data_pw("ntlmv2 clear data\n", data, length);
317 } else {
318 smb_arc4_crypt(ntlmssp_state->ntlmv1_arc4_state, data, length);
319 dump_data_pw("ntlmv1 clear data\n", data, length);
320 }
321 return ntlmssp_check_packet(ntlmssp_state, data, length, whole_pdu, pdu_length, sig);
322}
323
324/**
325 Initialise the state for NTLMSSP signing.
326*/
327NTSTATUS ntlmssp_sign_init(NTLMSSP_STATE *ntlmssp_state)
328{
329 unsigned char p24[24];
330 TALLOC_CTX *mem_ctx;
331 ZERO_STRUCT(p24);
332
333 mem_ctx = talloc_init("weak_keys");
334 if (!mem_ctx) {
335 return NT_STATUS_NO_MEMORY;
336 }
337
338 DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
339 debug_ntlmssp_flags(ntlmssp_state->neg_flags);
340
341 if (ntlmssp_state->session_key.length < 8) {
342 TALLOC_FREE(mem_ctx);
343 DEBUG(3, ("NO session key, cannot intialise signing\n"));
344 return NT_STATUS_NO_USER_SESSION_KEY;
345 }
346
347 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
348 DATA_BLOB weak_session_key = ntlmssp_state->session_key;
349 const char *send_sign_const;
350 const char *send_seal_const;
351 const char *recv_sign_const;
352 const char *recv_seal_const;
353
354 switch (ntlmssp_state->role) {
355 case NTLMSSP_CLIENT:
356 send_sign_const = CLI_SIGN;
357 send_seal_const = CLI_SEAL;
358 recv_sign_const = SRV_SIGN;
359 recv_seal_const = SRV_SEAL;
360 break;
361 case NTLMSSP_SERVER:
362 send_sign_const = SRV_SIGN;
363 send_seal_const = SRV_SEAL;
364 recv_sign_const = CLI_SIGN;
365 recv_seal_const = CLI_SEAL;
366 break;
367 default:
368 TALLOC_FREE(mem_ctx);
369 return NT_STATUS_INTERNAL_ERROR;
370 }
371
372 /**
373 Weaken NTLMSSP keys to cope with down-level clients, servers and export restrictions.
374 We probably should have some parameters to control this, once we get NTLM2 working.
375 */
376
377 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
378 ;
379 } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
380 weak_session_key.length = 7;
381 } else { /* forty bits */
382 weak_session_key.length = 5;
383 }
384
385 dump_data_pw("NTLMSSP weakend master key:\n",
386 weak_session_key.data,
387 weak_session_key.length);
388
389 /* SEND: sign key */
390 calc_ntlmv2_key(ntlmssp_state->send_sign_key,
391 ntlmssp_state->session_key, send_sign_const);
392 dump_data_pw("NTLMSSP send sign key:\n",
393 ntlmssp_state->send_sign_key, 16);
394
395 /* SEND: seal ARCFOUR pad */
396 calc_ntlmv2_key(ntlmssp_state->send_seal_key,
397 weak_session_key, send_seal_const);
398 dump_data_pw("NTLMSSP send seal key:\n",
399 ntlmssp_state->send_seal_key, 16);
400
401 smb_arc4_init(ntlmssp_state->send_seal_arc4_state,
402 ntlmssp_state->send_seal_key, 16);
403
404 dump_data_pw("NTLMSSP send seal arc4 state:\n",
405 ntlmssp_state->send_seal_arc4_state,
406 sizeof(ntlmssp_state->send_seal_arc4_state));
407
408 /* RECV: sign key */
409 calc_ntlmv2_key(ntlmssp_state->recv_sign_key,
410 ntlmssp_state->session_key, recv_sign_const);
411 dump_data_pw("NTLMSSP recv send sign key:\n",
412 ntlmssp_state->recv_sign_key, 16);
413
414 /* RECV: seal ARCFOUR pad */
415 calc_ntlmv2_key(ntlmssp_state->recv_seal_key,
416 weak_session_key, recv_seal_const);
417
418 dump_data_pw("NTLMSSP recv seal key:\n",
419 ntlmssp_state->recv_seal_key, 16);
420
421 smb_arc4_init(ntlmssp_state->recv_seal_arc4_state,
422 ntlmssp_state->recv_seal_key, 16);
423
424 dump_data_pw("NTLMSSP recv seal arc4 state:\n",
425 ntlmssp_state->recv_seal_arc4_state,
426 sizeof(ntlmssp_state->recv_seal_arc4_state));
427
428 ntlmssp_state->ntlm2_send_seq_num = 0;
429 ntlmssp_state->ntlm2_recv_seq_num = 0;
430
431
432 } else {
433#if 0
434 /* Hmmm. Shouldn't we also weaken keys for ntlmv1 ? JRA. */
435
436 DATA_BLOB weak_session_key = ntlmssp_state->session_key;
437 /**
438 Weaken NTLMSSP keys to cope with down-level clients, servers and export restrictions.
439 We probably should have some parameters to control this, once we get NTLM2 working.
440 */
441
442 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
443 ;
444 } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
445 weak_session_key.length = 6;
446 } else { /* forty bits */
447 weak_session_key.length = 5;
448 }
449 dump_data_pw("NTLMSSP weakend master key:\n",
450 weak_session_key.data,
451 weak_session_key.length);
452#endif
453
454 DATA_BLOB weak_session_key = ntlmssp_weaken_keys(ntlmssp_state, mem_ctx);
455
456 DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));
457
458 smb_arc4_init(ntlmssp_state->ntlmv1_arc4_state,
459 weak_session_key.data, weak_session_key.length);
460
461 dump_data_pw("NTLMv1 arc4 state:\n", ntlmssp_state->ntlmv1_arc4_state,
462 sizeof(ntlmssp_state->ntlmv1_arc4_state));
463
464 ntlmssp_state->ntlmv1_seq_num = 0;
465 }
466
467 TALLOC_FREE(mem_ctx);
468 return NT_STATUS_OK;
469}
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