2 Unix SMB/CIFS implementation.
4 Copyright (C) Jeremy Allison 2002.
5 Copyright (C) Andrew Bartlett <abartlet@samba.org> 2002-2003
6 Copyright (C) James J Myers <myersjj@samba.org> 2003
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 #include "libcli/raw/libcliraw.h"
26 #include "lib/crypto/crypto.h"
28 /***********************************************************
29 SMB signing - Common code before we set a new signing implementation
30 ************************************************************/
31 BOOL set_smb_signing_common(struct smb_signing_context *sign_info)
33 if (sign_info->doing_signing) {
34 DEBUG(5, ("SMB Signing already in progress, so we don't start it again\n"));
38 if (!sign_info->allow_smb_signing) {
39 DEBUG(5, ("SMB Signing has been locally disabled\n"));
46 /***********************************************************
47 SMB signing - Common code before we set a new signing implementation
48 ************************************************************/
49 static BOOL smbcli_set_smb_signing_common(struct smbcli_transport *transport)
51 if (!set_smb_signing_common(&transport->negotiate.sign_info)) {
55 if (!(transport->negotiate.sec_mode &
56 (NEGOTIATE_SECURITY_SIGNATURES_REQUIRED|NEGOTIATE_SECURITY_SIGNATURES_ENABLED))) {
57 DEBUG(5, ("SMB Signing is not negotiated by the peer\n"));
61 /* These calls are INCOMPATIBLE with SMB signing */
62 transport->negotiate.readbraw_supported = False;
63 transport->negotiate.writebraw_supported = False;
68 void mark_packet_signed(struct request_buffer *out)
71 flags2 = SVAL(out->hdr, HDR_FLG2);
72 flags2 |= FLAGS2_SMB_SECURITY_SIGNATURES;
73 SSVAL(out->hdr, HDR_FLG2, flags2);
76 BOOL signing_good(struct smb_signing_context *sign_info,
77 unsigned int seq, BOOL good)
80 if (!sign_info->doing_signing) {
81 DEBUG(5, ("Seen valid packet, so turning signing on\n"));
82 sign_info->doing_signing = True;
84 if (!sign_info->seen_valid) {
85 DEBUG(5, ("Seen valid packet, so marking signing as 'seen valid'\n"));
86 sign_info->seen_valid = True;
89 if (!sign_info->seen_valid) {
90 /* If we have never seen a good packet, just turn it off */
91 DEBUG(5, ("signing_good: signing negotiated but not required and peer\n"
92 "isn't sending correct signatures. Turning off.\n"));
93 smbcli_set_signing_off(sign_info);
96 /* bad packet after signing started - fail and disconnect. */
97 DEBUG(0, ("signing_good: BAD SIG: seq %u\n", seq));
104 void sign_outgoing_message(struct request_buffer *out, DATA_BLOB *mac_key, uint_t seq_num)
106 uint8_t calc_md5_mac[16];
107 struct MD5Context md5_ctx;
110 * Firstly put the sequence number into the first 4 bytes.
111 * and zero out the next 4 bytes.
113 SIVAL(out->hdr, HDR_SS_FIELD, seq_num);
114 SIVAL(out->hdr, HDR_SS_FIELD + 4, 0);
116 /* mark the packet as signed - BEFORE we sign it...*/
117 mark_packet_signed(out);
119 /* Calculate the 16 byte MAC and place first 8 bytes into the field. */
121 MD5Update(&md5_ctx, mac_key->data, mac_key->length);
123 out->buffer + NBT_HDR_SIZE,
124 out->size - NBT_HDR_SIZE);
125 MD5Final(calc_md5_mac, &md5_ctx);
127 memcpy(&out->hdr[HDR_SS_FIELD], calc_md5_mac, 8);
129 DEBUG(5, ("sign_outgoing_message: SENT SIG (seq: %d): sent SMB signature of\n",
131 dump_data(5, calc_md5_mac, 8);
132 /* req->out.hdr[HDR_SS_FIELD+2]=0;
133 Uncomment this to test if the remote server actually verifies signitures...*/
136 BOOL check_signed_incoming_message(struct request_buffer *in, DATA_BLOB *mac_key, uint_t seq_num)
139 uint8_t calc_md5_mac[16];
140 uint8_t *server_sent_mac;
141 uint8_t sequence_buf[8];
142 struct MD5Context md5_ctx;
143 const size_t offset_end_of_sig = (HDR_SS_FIELD + 8);
145 const int sign_range = 0;
147 /* room enough for the signature? */
148 if (in->size < NBT_HDR_SIZE + HDR_SS_FIELD + 8) {
152 if (!mac_key->length) {
157 /* its quite bogus to be guessing sequence numbers, but very useful
158 when debugging signing implementations */
159 for (i = 0-sign_range; i <= 0+sign_range; i++) {
161 * Firstly put the sequence number into the first 4 bytes.
162 * and zero out the next 4 bytes.
164 SIVAL(sequence_buf, 0, seq_num + i);
165 SIVAL(sequence_buf, 4, 0);
167 /* get a copy of the server-sent mac */
168 server_sent_mac = &in->hdr[HDR_SS_FIELD];
170 /* Calculate the 16 byte MAC and place first 8 bytes into the field. */
172 MD5Update(&md5_ctx, mac_key->data,
174 MD5Update(&md5_ctx, in->hdr, HDR_SS_FIELD);
175 MD5Update(&md5_ctx, sequence_buf, sizeof(sequence_buf));
177 MD5Update(&md5_ctx, in->hdr + offset_end_of_sig,
178 in->size - NBT_HDR_SIZE - (offset_end_of_sig));
179 MD5Final(calc_md5_mac, &md5_ctx);
181 good = (memcmp(server_sent_mac, calc_md5_mac, 8) == 0);
185 DEBUG(5, ("check_signed_incoming_message: BAD SIG (seq: %d): wanted SMB signature of\n", seq_num + i));
186 dump_data(5, calc_md5_mac, 8);
188 DEBUG(5, ("check_signed_incoming_message: BAD SIG (seq: %d): got SMB signature of\n", seq_num + i));
189 dump_data(5, server_sent_mac, 8);
191 DEBUG(15, ("check_signed_incoming_message: GOOD SIG (seq: %d): got SMB signature of\n", seq_num + i));
192 dump_data(5, server_sent_mac, 8);
199 if (good && i != 0) {
200 DEBUG(0,("SIGNING OFFSET %d (should be %d)\n", i, seq_num));
206 static void smbcli_req_allocate_seq_num(struct smbcli_request *req)
208 req->seq_num = req->transport->negotiate.sign_info.next_seq_num;
210 /* some requests (eg. NTcancel) are one way, and the sequence number
211 should be increased by 1 not 2 */
212 if (req->sign_single_increment) {
213 req->transport->negotiate.sign_info.next_seq_num += 1;
215 req->transport->negotiate.sign_info.next_seq_num += 2;
219 /***********************************************************
220 SMB signing - Simple implementation - calculate a MAC to send.
221 ************************************************************/
222 void smbcli_request_calculate_sign_mac(struct smbcli_request *req)
225 /* enable this when packet signing is preventing you working out why valgrind
226 says that data is uninitialised */
227 file_save("pkt.dat", req->out.buffer, req->out.size);
230 switch (req->transport->negotiate.sign_info.signing_state) {
231 case SMB_SIGNING_ENGINE_OFF:
234 case SMB_SIGNING_ENGINE_BSRSPYL:
235 /* mark the packet as signed - BEFORE we sign it...*/
236 mark_packet_signed(&req->out);
238 /* I wonder what BSRSPYL stands for - but this is what MS
240 memcpy((req->out.hdr + HDR_SS_FIELD), "BSRSPYL ", 8);
243 case SMB_SIGNING_ENGINE_ON:
245 smbcli_req_allocate_seq_num(req);
246 sign_outgoing_message(&req->out,
247 &req->transport->negotiate.sign_info.mac_key,
256 SMB signing - NULL implementation
258 @note Used as an initialisation only - it will not correctly
259 shut down a real signing mechanism
261 BOOL smbcli_set_signing_off(struct smb_signing_context *sign_info)
263 DEBUG(5, ("Shutdown SMB signing\n"));
264 sign_info->doing_signing = False;
265 sign_info->next_seq_num = 0;
266 data_blob_free(&sign_info->mac_key);
267 sign_info->signing_state = SMB_SIGNING_ENGINE_OFF;
272 SMB signing - TEMP implementation - setup the MAC key.
275 BOOL smbcli_temp_set_signing(struct smbcli_transport *transport)
277 if (!smbcli_set_smb_signing_common(transport)) {
280 DEBUG(5, ("BSRSPYL SMB signing enabled\n"));
281 smbcli_set_signing_off(&transport->negotiate.sign_info);
283 transport->negotiate.sign_info.mac_key = data_blob(NULL, 0);
284 transport->negotiate.sign_info.signing_state = SMB_SIGNING_ENGINE_BSRSPYL;
289 /***********************************************************
290 SMB signing - Simple implementation - check a MAC sent by server.
291 ************************************************************/
293 * Check a packet supplied by the server.
294 * @return False if we had an established signing connection
295 * which had a back checksum, True otherwise
297 BOOL smbcli_request_check_sign_mac(struct smbcli_request *req)
301 switch (req->transport->negotiate.sign_info.signing_state)
303 case SMB_SIGNING_ENGINE_OFF:
305 case SMB_SIGNING_ENGINE_BSRSPYL:
306 case SMB_SIGNING_ENGINE_ON:
308 if (req->in.size < (HDR_SS_FIELD + 8)) {
311 good = check_signed_incoming_message(&req->in,
312 &req->transport->negotiate.sign_info.mac_key,
315 return signing_good(&req->transport->negotiate.sign_info,
316 req->seq_num+1, good);
324 /***********************************************************
325 SMB signing - Simple implementation - setup the MAC key.
326 ************************************************************/
327 BOOL smbcli_simple_set_signing(TALLOC_CTX *mem_ctx,
328 struct smb_signing_context *sign_info,
329 const DATA_BLOB *user_session_key,
330 const DATA_BLOB *response)
332 if (sign_info->mandatory_signing) {
333 DEBUG(5, ("Mandatory SMB signing enabled!\n"));
336 DEBUG(5, ("SMB signing enabled!\n"));
338 if (response && response->length) {
339 sign_info->mac_key = data_blob_talloc(mem_ctx, NULL, response->length + user_session_key->length);
341 sign_info->mac_key = data_blob_talloc(mem_ctx, NULL, user_session_key->length);
344 memcpy(&sign_info->mac_key.data[0], user_session_key->data, user_session_key->length);
346 if (response && response->length) {
347 memcpy(&sign_info->mac_key.data[user_session_key->length],response->data, response->length);
350 dump_data_pw("Started Signing with key:\n", sign_info->mac_key.data, sign_info->mac_key.length);
352 /* Initialise the sequence number */
353 sign_info->next_seq_num = 0;
355 sign_info->signing_state = SMB_SIGNING_ENGINE_ON;
361 /***********************************************************
362 SMB signing - Simple implementation - setup the MAC key.
363 ************************************************************/
364 BOOL smbcli_transport_simple_set_signing(struct smbcli_transport *transport,
365 const DATA_BLOB user_session_key,
366 const DATA_BLOB response)
368 if (!smbcli_set_smb_signing_common(transport)) {
372 return smbcli_simple_set_signing(transport,
373 &transport->negotiate.sign_info,
379 BOOL smbcli_init_signing(struct smbcli_transport *transport)
381 transport->negotiate.sign_info.mac_key = data_blob(NULL, 0);
382 if (!smbcli_set_signing_off(&transport->negotiate.sign_info)) {
386 switch (lp_client_signing()) {
387 case SMB_SIGNING_OFF:
388 transport->negotiate.sign_info.allow_smb_signing = False;
390 case SMB_SIGNING_SUPPORTED:
391 case SMB_SIGNING_AUTO:
392 transport->negotiate.sign_info.allow_smb_signing = True;
394 case SMB_SIGNING_REQUIRED:
395 transport->negotiate.sign_info.allow_smb_signing = True;
396 transport->negotiate.sign_info.mandatory_signing = True;