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Linux/fs/cifs/smb2transport.c

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  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
 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                 cERROR(1, "%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                 cERROR(1, "%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                         cERROR(1, "null iovec entry");
 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                         cERROR(1, "%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                 cERROR(1, "%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
120 smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
121 {
122         cFYI(1, "smb3 signatures not supported yet");
123         return -EOPNOTSUPP;
124 }
125 
126 /* must be called with server->srv_mutex held */
127 static int
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
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                 cFYI(1, "dummy signature received for smb command 0x%x",
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
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 *
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                 cERROR(1, "Null TCP session in smb2_mid_entry_alloc");
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
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                 cFYI(1, "tcp session dead - return to caller to retry");
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
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                         cERROR(1, "SMB signature verification returned error = "
285                                "%d", rc);
286         }
287 
288         return map_smb2_to_linux_error(mid->resp_buf, log_error);
289 }
290 
291 struct mid_q_entry *
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 *
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 

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