1 /*
2 * fs/cifs/smb2transport.c
3 *
4 * Copyright (C) International Business Machines Corp., 2002, 2011
5 * Etersoft, 2012
6 * Author(s): Steve French (sfrench@us.ibm.com)
7 * Jeremy Allison (jra@samba.org) 2006
8 * Pavel Shilovsky (pshilovsky@samba.org) 2012
9 *
10 * This library is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU Lesser General Public License as published
12 * by the Free Software Foundation; either version 2.1 of the License, or
13 * (at your option) any later version.
14 *
15 * This library is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
18 * the GNU Lesser General Public License for more details.
19 *
20 * You should have received a copy of the GNU Lesser General Public License
21 * along with this library; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 */
24
25 #include <linux/fs.h>
26 #include <linux/list.h>
27 #include <linux/wait.h>
28 #include <linux/net.h>
29 #include <linux/delay.h>
30 #include <linux/uaccess.h>
31 #include <asm/processor.h>
32 #include <linux/mempool.h>
33 #include <linux/highmem.h>
34 #include "smb2pdu.h"
35 #include "cifsglob.h"
36 #include "cifsproto.h"
37 #include "smb2proto.h"
38 #include "cifs_debug.h"
39 #include "smb2status.h"
40 #include "smb2glob.h"
41
42 int
smb2_calc_signature(struct smb_rqst * rqst,struct TCP_Server_Info * server)43 smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
44 {
45 int i, rc;
46 unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
47 unsigned char *sigptr = smb2_signature;
48 struct kvec *iov = rqst->rq_iov;
49 int n_vec = rqst->rq_nvec;
50 struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
51
52 memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
53 memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
54
55 rc = crypto_shash_setkey(server->secmech.hmacsha256,
56 server->session_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
57 if (rc) {
58 cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
59 return rc;
60 }
61
62 rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
63 if (rc) {
64 cifs_dbg(VFS, "%s: Could not init md5\n", __func__);
65 return rc;
66 }
67
68 for (i = 0; i < n_vec; i++) {
69 if (iov[i].iov_len == 0)
70 continue;
71 if (iov[i].iov_base == NULL) {
72 cifs_dbg(VFS, "null iovec entry\n");
73 return -EIO;
74 }
75 /*
76 * The first entry includes a length field (which does not get
77 * signed that occupies the first 4 bytes before the header).
78 */
79 if (i == 0) {
80 if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
81 break; /* nothing to sign or corrupt header */
82 rc =
83 crypto_shash_update(
84 &server->secmech.sdeschmacsha256->shash,
85 iov[i].iov_base + 4, iov[i].iov_len - 4);
86 } else {
87 rc =
88 crypto_shash_update(
89 &server->secmech.sdeschmacsha256->shash,
90 iov[i].iov_base, iov[i].iov_len);
91 }
92 if (rc) {
93 cifs_dbg(VFS, "%s: Could not update with payload\n",
94 __func__);
95 return rc;
96 }
97 }
98
99 /* now hash over the rq_pages array */
100 for (i = 0; i < rqst->rq_npages; i++) {
101 struct kvec p_iov;
102
103 cifs_rqst_page_to_kvec(rqst, i, &p_iov);
104 crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
105 p_iov.iov_base, p_iov.iov_len);
106 kunmap(rqst->rq_pages[i]);
107 }
108
109 rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
110 sigptr);
111 if (rc)
112 cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
113
114 memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
115
116 return rc;
117 }
118
119 int
smb3_calc_signature(struct smb_rqst * rqst,struct TCP_Server_Info * server)120 smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
121 {
122 cifs_dbg(FYI, "smb3 signatures not supported yet\n");
123 return -EOPNOTSUPP;
124 }
125
126 /* must be called with server->srv_mutex held */
127 static int
smb2_sign_rqst(struct smb_rqst * rqst,struct TCP_Server_Info * server)128 smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
129 {
130 int rc = 0;
131 struct smb2_hdr *smb2_pdu = rqst->rq_iov[0].iov_base;
132
133 if (!(smb2_pdu->Flags & SMB2_FLAGS_SIGNED) ||
134 server->tcpStatus == CifsNeedNegotiate)
135 return rc;
136
137 if (!server->session_estab) {
138 strncpy(smb2_pdu->Signature, "BSRSPYL", 8);
139 return rc;
140 }
141
142 rc = server->ops->calc_signature(rqst, server);
143
144 return rc;
145 }
146
147 int
smb2_verify_signature(struct smb_rqst * rqst,struct TCP_Server_Info * server)148 smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
149 {
150 unsigned int rc;
151 char server_response_sig[16];
152 struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
153
154 if ((smb2_pdu->Command == SMB2_NEGOTIATE) ||
155 (smb2_pdu->Command == SMB2_OPLOCK_BREAK) ||
156 (!server->session_estab))
157 return 0;
158
159 /*
160 * BB what if signatures are supposed to be on for session but
161 * server does not send one? BB
162 */
163
164 /* Do not need to verify session setups with signature "BSRSPYL " */
165 if (memcmp(smb2_pdu->Signature, "BSRSPYL ", 8) == 0)
166 cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
167 smb2_pdu->Command);
168
169 /*
170 * Save off the origiginal signature so we can modify the smb and check
171 * our calculated signature against what the server sent.
172 */
173 memcpy(server_response_sig, smb2_pdu->Signature, SMB2_SIGNATURE_SIZE);
174
175 memset(smb2_pdu->Signature, 0, SMB2_SIGNATURE_SIZE);
176
177 mutex_lock(&server->srv_mutex);
178 rc = server->ops->calc_signature(rqst, server);
179 mutex_unlock(&server->srv_mutex);
180
181 if (rc)
182 return rc;
183
184 if (memcmp(server_response_sig, smb2_pdu->Signature,
185 SMB2_SIGNATURE_SIZE))
186 return -EACCES;
187 else
188 return 0;
189 }
190
191 /*
192 * Set message id for the request. Should be called after wait_for_free_request
193 * and when srv_mutex is held.
194 */
195 static inline void
smb2_seq_num_into_buf(struct TCP_Server_Info * server,struct smb2_hdr * hdr)196 smb2_seq_num_into_buf(struct TCP_Server_Info *server, struct smb2_hdr *hdr)
197 {
198 hdr->MessageId = get_next_mid(server);
199 }
200
201 static struct mid_q_entry *
smb2_mid_entry_alloc(const struct smb2_hdr * smb_buffer,struct TCP_Server_Info * server)202 smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
203 struct TCP_Server_Info *server)
204 {
205 struct mid_q_entry *temp;
206
207 if (server == NULL) {
208 cifs_dbg(VFS, "Null TCP session in smb2_mid_entry_alloc\n");
209 return NULL;
210 }
211
212 temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
213 if (temp == NULL)
214 return temp;
215 else {
216 memset(temp, 0, sizeof(struct mid_q_entry));
217 temp->mid = smb_buffer->MessageId; /* always LE */
218 temp->pid = current->pid;
219 temp->command = smb_buffer->Command; /* Always LE */
220 temp->when_alloc = jiffies;
221 temp->server = server;
222
223 /*
224 * The default is for the mid to be synchronous, so the
225 * default callback just wakes up the current task.
226 */
227 temp->callback = cifs_wake_up_task;
228 temp->callback_data = current;
229 }
230
231 atomic_inc(&midCount);
232 temp->mid_state = MID_REQUEST_ALLOCATED;
233 return temp;
234 }
235
236 static int
smb2_get_mid_entry(struct cifs_ses * ses,struct smb2_hdr * buf,struct mid_q_entry ** mid)237 smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
238 struct mid_q_entry **mid)
239 {
240 if (ses->server->tcpStatus == CifsExiting)
241 return -ENOENT;
242
243 if (ses->server->tcpStatus == CifsNeedReconnect) {
244 cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
245 return -EAGAIN;
246 }
247
248 if (ses->status != CifsGood) {
249 /* check if SMB2 session is bad because we are setting it up */
250 if ((buf->Command != SMB2_SESSION_SETUP) &&
251 (buf->Command != SMB2_NEGOTIATE))
252 return -EAGAIN;
253 /* else ok - we are setting up session */
254 }
255 *mid = smb2_mid_entry_alloc(buf, ses->server);
256 if (*mid == NULL)
257 return -ENOMEM;
258 spin_lock(&GlobalMid_Lock);
259 list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
260 spin_unlock(&GlobalMid_Lock);
261 return 0;
262 }
263
264 int
smb2_check_receive(struct mid_q_entry * mid,struct TCP_Server_Info * server,bool log_error)265 smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
266 bool log_error)
267 {
268 unsigned int len = get_rfc1002_length(mid->resp_buf);
269 struct kvec iov;
270 struct smb_rqst rqst = { .rq_iov = &iov,
271 .rq_nvec = 1 };
272
273 iov.iov_base = (char *)mid->resp_buf;
274 iov.iov_len = get_rfc1002_length(mid->resp_buf) + 4;
275
276 dump_smb(mid->resp_buf, min_t(u32, 80, len));
277 /* convert the length into a more usable form */
278 if ((len > 24) &&
279 (server->sec_mode & (SECMODE_SIGN_REQUIRED|SECMODE_SIGN_ENABLED))) {
280 int rc;
281
282 rc = smb2_verify_signature(&rqst, server);
283 if (rc)
284 cifs_dbg(VFS, "SMB signature verification returned error = %d\n",
285 rc);
286 }
287
288 return map_smb2_to_linux_error(mid->resp_buf, log_error);
289 }
290
291 struct mid_q_entry *
smb2_setup_request(struct cifs_ses * ses,struct smb_rqst * rqst)292 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
293 {
294 int rc;
295 struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
296 struct mid_q_entry *mid;
297
298 smb2_seq_num_into_buf(ses->server, hdr);
299
300 rc = smb2_get_mid_entry(ses, hdr, &mid);
301 if (rc)
302 return ERR_PTR(rc);
303 rc = smb2_sign_rqst(rqst, ses->server);
304 if (rc) {
305 cifs_delete_mid(mid);
306 return ERR_PTR(rc);
307 }
308 return mid;
309 }
310
311 struct mid_q_entry *
smb2_setup_async_request(struct TCP_Server_Info * server,struct smb_rqst * rqst)312 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
313 {
314 int rc;
315 struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
316 struct mid_q_entry *mid;
317
318 smb2_seq_num_into_buf(server, hdr);
319
320 mid = smb2_mid_entry_alloc(hdr, server);
321 if (mid == NULL)
322 return ERR_PTR(-ENOMEM);
323
324 rc = smb2_sign_rqst(rqst, server);
325 if (rc) {
326 DeleteMidQEntry(mid);
327 return ERR_PTR(rc);
328 }
329
330 return mid;
331 }
332