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 3 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, see <http://www.gnu.org/licenses/>.
24 #include "libcli/raw/libcliraw.h"
25 #include "libcli/raw/raw_proto.h"
26 #include "lib/crypto/crypto.h"
27 #include "param/param.h"
29 /***********************************************************
30 SMB signing - Common code before we set a new signing implementation
31 ************************************************************/
32 bool set_smb_signing_common(struct smb_signing_context *sign_info)
34 if (sign_info->doing_signing) {
35 DEBUG(5, ("SMB Signing already in progress, so we don't start it again\n"));
39 if (!sign_info->allow_smb_signing) {
40 DEBUG(5, ("SMB Signing has been locally disabled\n"));
47 /***********************************************************
48 SMB signing - Common code before we set a new signing implementation
49 ************************************************************/
50 static bool smbcli_set_smb_signing_common(struct smbcli_transport *transport)
52 if (!set_smb_signing_common(&transport->negotiate.sign_info)) {
56 if (!(transport->negotiate.sec_mode &
57 (NEGOTIATE_SECURITY_SIGNATURES_REQUIRED|NEGOTIATE_SECURITY_SIGNATURES_ENABLED))) {
58 DEBUG(5, ("SMB Signing is not negotiated by the peer\n"));
62 /* These calls are INCOMPATIBLE with SMB signing */
63 transport->negotiate.readbraw_supported = false;
64 transport->negotiate.writebraw_supported = false;
69 void mark_packet_signed(struct smb_request_buffer *out)
72 flags2 = SVAL(out->hdr, HDR_FLG2);
73 flags2 |= FLAGS2_SMB_SECURITY_SIGNATURES;
74 SSVAL(out->hdr, HDR_FLG2, flags2);
77 bool signing_good(struct smb_signing_context *sign_info,
78 unsigned int seq, bool good)
81 if (!sign_info->doing_signing) {
82 DEBUG(5, ("Seen valid packet, so turning signing on\n"));
83 sign_info->doing_signing = true;
85 if (!sign_info->seen_valid) {
86 DEBUG(5, ("Seen valid packet, so marking signing as 'seen valid'\n"));
87 sign_info->seen_valid = true;
90 if (!sign_info->seen_valid) {
91 /* If we have never seen a good packet, just turn it off */
92 DEBUG(5, ("signing_good: signing negotiated but not required and peer\n"
93 "isn't sending correct signatures. Turning off.\n"));
94 smbcli_set_signing_off(sign_info);
97 /* bad packet after signing started - fail and disconnect. */
98 DEBUG(0, ("signing_good: BAD SIG: seq %u\n", seq));
105 void sign_outgoing_message(struct smb_request_buffer *out, DATA_BLOB *mac_key, unsigned int seq_num)
107 uint8_t calc_md5_mac[16];
108 struct MD5Context md5_ctx;
111 * Firstly put the sequence number into the first 4 bytes.
112 * and zero out the next 4 bytes.
114 SIVAL(out->hdr, HDR_SS_FIELD, seq_num);
115 SIVAL(out->hdr, HDR_SS_FIELD + 4, 0);
117 /* mark the packet as signed - BEFORE we sign it...*/
118 mark_packet_signed(out);
120 /* Calculate the 16 byte MAC and place first 8 bytes into the field. */
122 MD5Update(&md5_ctx, mac_key->data, mac_key->length);
124 out->buffer + NBT_HDR_SIZE,
125 out->size - NBT_HDR_SIZE);
126 MD5Final(calc_md5_mac, &md5_ctx);
128 memcpy(&out->hdr[HDR_SS_FIELD], calc_md5_mac, 8);
130 DEBUG(5, ("sign_outgoing_message: SENT SIG (seq: %d): sent SMB signature of\n",
132 dump_data(5, calc_md5_mac, 8);
133 /* req->out.hdr[HDR_SS_FIELD+2]=0;
134 Uncomment this to test if the remote server actually verifies signitures...*/
137 bool check_signed_incoming_message(struct smb_request_buffer *in, DATA_BLOB *mac_key, uint_t seq_num)
140 uint8_t calc_md5_mac[16];
141 uint8_t *server_sent_mac;
142 uint8_t sequence_buf[8];
143 struct MD5Context md5_ctx;
144 const size_t offset_end_of_sig = (HDR_SS_FIELD + 8);
146 const int sign_range = 0;
148 /* room enough for the signature? */
149 if (in->size < NBT_HDR_SIZE + HDR_SS_FIELD + 8) {
153 if (!mac_key->length) {
158 /* its quite bogus to be guessing sequence numbers, but very useful
159 when debugging signing implementations */
160 for (i = 0-sign_range; i <= 0+sign_range; i++) {
162 * Firstly put the sequence number into the first 4 bytes.
163 * and zero out the next 4 bytes.
165 SIVAL(sequence_buf, 0, seq_num + i);
166 SIVAL(sequence_buf, 4, 0);
168 /* get a copy of the server-sent mac */
169 server_sent_mac = &in->hdr[HDR_SS_FIELD];
171 /* Calculate the 16 byte MAC and place first 8 bytes into the field. */
173 MD5Update(&md5_ctx, mac_key->data,
175 MD5Update(&md5_ctx, in->hdr, HDR_SS_FIELD);
176 MD5Update(&md5_ctx, sequence_buf, sizeof(sequence_buf));
178 MD5Update(&md5_ctx, in->hdr + offset_end_of_sig,
179 in->size - NBT_HDR_SIZE - (offset_end_of_sig));
180 MD5Final(calc_md5_mac, &md5_ctx);
182 good = (memcmp(server_sent_mac, calc_md5_mac, 8) == 0);
186 DEBUG(5, ("check_signed_incoming_message: BAD SIG (seq: %d): wanted SMB signature of\n", seq_num + i));
187 dump_data(5, calc_md5_mac, 8);
189 DEBUG(5, ("check_signed_incoming_message: BAD SIG (seq: %d): got SMB signature of\n", seq_num + i));
190 dump_data(5, server_sent_mac, 8);
192 DEBUG(15, ("check_signed_incoming_message: GOOD SIG (seq: %d): got SMB signature of\n", seq_num + i));
193 dump_data(5, server_sent_mac, 8);
200 if (good && i != 0) {
201 DEBUG(0,("SIGNING OFFSET %d (should be %d)\n", i, seq_num));
207 static void smbcli_req_allocate_seq_num(struct smbcli_request *req)
209 req->seq_num = req->transport->negotiate.sign_info.next_seq_num;
211 /* some requests (eg. NTcancel) are one way, and the sequence number
212 should be increased by 1 not 2 */
213 if (req->sign_single_increment) {
214 req->transport->negotiate.sign_info.next_seq_num += 1;
216 req->transport->negotiate.sign_info.next_seq_num += 2;
220 /***********************************************************
221 SMB signing - Simple implementation - calculate a MAC to send.
222 ************************************************************/
223 void smbcli_request_calculate_sign_mac(struct smbcli_request *req)
225 const uint8_t *signature;
227 /* enable this when packet signing is preventing you working out why valgrind
228 says that data is uninitialised */
229 file_save("pkt.dat", req->out.buffer, req->out.size);
232 switch (req->transport->negotiate.sign_info.signing_state) {
233 case SMB_SIGNING_ENGINE_OFF:
236 case SMB_SIGNING_ENGINE_BSRSPYL:
237 if (req->in.size >= (HDR_SS_FIELD + 8) && req->in.hdr) {
238 /* as server we just echo the signature from the client */
239 signature = req->in.hdr + HDR_SS_FIELD;
242 * I wonder what BSRSPYL stands for - but this is what MS
245 signature = (const uint8_t *)"BSRSPYL ";
248 /* mark the packet as signed - BEFORE we sign it...*/
249 mark_packet_signed(&req->out);
251 memcpy((req->out.hdr + HDR_SS_FIELD), signature, 8);
254 case SMB_SIGNING_ENGINE_ON:
256 smbcli_req_allocate_seq_num(req);
257 sign_outgoing_message(&req->out,
258 &req->transport->negotiate.sign_info.mac_key,
267 SMB signing - NULL implementation
269 @note Used as an initialisation only - it will not correctly
270 shut down a real signing mechanism
272 bool smbcli_set_signing_off(struct smb_signing_context *sign_info)
274 DEBUG(5, ("Shutdown SMB signing\n"));
275 sign_info->doing_signing = false;
276 data_blob_free(&sign_info->mac_key);
277 sign_info->signing_state = SMB_SIGNING_ENGINE_OFF;
282 SMB signing - TEMP implementation - setup the MAC key.
285 bool smbcli_temp_set_signing(struct smbcli_transport *transport)
287 if (!smbcli_set_smb_signing_common(transport)) {
290 DEBUG(5, ("BSRSPYL SMB signing enabled\n"));
291 smbcli_set_signing_off(&transport->negotiate.sign_info);
293 transport->negotiate.sign_info.mac_key = data_blob(NULL, 0);
294 transport->negotiate.sign_info.signing_state = SMB_SIGNING_ENGINE_BSRSPYL;
299 /***********************************************************
300 SMB signing - Simple implementation - check a MAC sent by server.
301 ************************************************************/
303 * Check a packet supplied by the server.
304 * @return false if we had an established signing connection
305 * which had a back checksum, true otherwise
307 bool smbcli_request_check_sign_mac(struct smbcli_request *req)
311 if (!req->transport->negotiate.sign_info.doing_signing &&
312 req->sign_caller_checks) {
316 req->sign_caller_checks = false;
318 switch (req->transport->negotiate.sign_info.signing_state)
320 case SMB_SIGNING_ENGINE_OFF:
322 case SMB_SIGNING_ENGINE_BSRSPYL:
323 if (req->in.size < (HDR_SS_FIELD + 8)) {
327 good = check_signed_incoming_message(&req->in,
328 &req->transport->negotiate.sign_info.mac_key,
331 return signing_good(&req->transport->negotiate.sign_info,
332 req->seq_num+1, good);
335 * It's not an error if the signature isn't valid.
336 * It could be "BSRSPYL " or any other value
340 case SMB_SIGNING_ENGINE_ON:
342 if (req->in.size < (HDR_SS_FIELD + 8)) {
345 good = check_signed_incoming_message(&req->in,
346 &req->transport->negotiate.sign_info.mac_key,
349 return signing_good(&req->transport->negotiate.sign_info,
350 req->seq_num+1, good);
358 /***********************************************************
359 SMB signing - Simple implementation - setup the MAC key.
360 ************************************************************/
361 bool smbcli_simple_set_signing(TALLOC_CTX *mem_ctx,
362 struct smb_signing_context *sign_info,
363 const DATA_BLOB *user_session_key,
364 const DATA_BLOB *response)
366 if (sign_info->mandatory_signing) {
367 DEBUG(5, ("Mandatory SMB signing enabled!\n"));
370 DEBUG(5, ("SMB signing enabled!\n"));
372 if (response && response->length) {
373 sign_info->mac_key = data_blob_talloc(mem_ctx, NULL, response->length + user_session_key->length);
375 sign_info->mac_key = data_blob_talloc(mem_ctx, NULL, user_session_key->length);
378 memcpy(&sign_info->mac_key.data[0], user_session_key->data, user_session_key->length);
380 if (response && response->length) {
381 memcpy(&sign_info->mac_key.data[user_session_key->length],response->data, response->length);
384 dump_data_pw("Started Signing with key:\n", sign_info->mac_key.data, sign_info->mac_key.length);
386 sign_info->signing_state = SMB_SIGNING_ENGINE_ON;
392 /***********************************************************
393 SMB signing - Simple implementation - setup the MAC key.
394 ************************************************************/
395 bool smbcli_transport_simple_set_signing(struct smbcli_transport *transport,
396 const DATA_BLOB user_session_key,
397 const DATA_BLOB response)
399 if (!smbcli_set_smb_signing_common(transport)) {
403 return smbcli_simple_set_signing(transport,
404 &transport->negotiate.sign_info,
410 bool smbcli_init_signing(struct smbcli_transport *transport)
412 transport->negotiate.sign_info.next_seq_num = 0;
413 transport->negotiate.sign_info.mac_key = data_blob(NULL, 0);
414 if (!smbcli_set_signing_off(&transport->negotiate.sign_info)) {
418 switch (transport->options.signing) {
419 case SMB_SIGNING_OFF:
420 transport->negotiate.sign_info.allow_smb_signing = false;
422 case SMB_SIGNING_SUPPORTED:
423 case SMB_SIGNING_AUTO:
424 transport->negotiate.sign_info.allow_smb_signing = true;
426 case SMB_SIGNING_REQUIRED:
427 transport->negotiate.sign_info.allow_smb_signing = true;
428 transport->negotiate.sign_info.mandatory_signing = true;