shmem: fix faulting into a hole, not taking i_mutex
[platform/adaptation/renesas_rcar/renesas_kernel.git] / fs / cifs / smb2transport.c
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 static int
43 smb2_crypto_shash_allocate(struct TCP_Server_Info *server)
44 {
45         int rc;
46         unsigned int size;
47
48         if (server->secmech.sdeschmacsha256 != NULL)
49                 return 0; /* already allocated */
50
51         server->secmech.hmacsha256 = crypto_alloc_shash("hmac(sha256)", 0, 0);
52         if (IS_ERR(server->secmech.hmacsha256)) {
53                 cifs_dbg(VFS, "could not allocate crypto hmacsha256\n");
54                 rc = PTR_ERR(server->secmech.hmacsha256);
55                 server->secmech.hmacsha256 = NULL;
56                 return rc;
57         }
58
59         size = sizeof(struct shash_desc) +
60                         crypto_shash_descsize(server->secmech.hmacsha256);
61         server->secmech.sdeschmacsha256 = kmalloc(size, GFP_KERNEL);
62         if (!server->secmech.sdeschmacsha256) {
63                 crypto_free_shash(server->secmech.hmacsha256);
64                 server->secmech.hmacsha256 = NULL;
65                 return -ENOMEM;
66         }
67         server->secmech.sdeschmacsha256->shash.tfm = server->secmech.hmacsha256;
68         server->secmech.sdeschmacsha256->shash.flags = 0x0;
69
70         return 0;
71 }
72
73 static int
74 smb3_crypto_shash_allocate(struct TCP_Server_Info *server)
75 {
76         unsigned int size;
77         int rc;
78
79         if (server->secmech.sdesccmacaes != NULL)
80                 return 0;  /* already allocated */
81
82         rc = smb2_crypto_shash_allocate(server);
83         if (rc)
84                 return rc;
85
86         server->secmech.cmacaes = crypto_alloc_shash("cmac(aes)", 0, 0);
87         if (IS_ERR(server->secmech.cmacaes)) {
88                 cifs_dbg(VFS, "could not allocate crypto cmac-aes");
89                 kfree(server->secmech.sdeschmacsha256);
90                 server->secmech.sdeschmacsha256 = NULL;
91                 crypto_free_shash(server->secmech.hmacsha256);
92                 server->secmech.hmacsha256 = NULL;
93                 rc = PTR_ERR(server->secmech.cmacaes);
94                 server->secmech.cmacaes = NULL;
95                 return rc;
96         }
97
98         size = sizeof(struct shash_desc) +
99                         crypto_shash_descsize(server->secmech.cmacaes);
100         server->secmech.sdesccmacaes = kmalloc(size, GFP_KERNEL);
101         if (!server->secmech.sdesccmacaes) {
102                 cifs_dbg(VFS, "%s: Can't alloc cmacaes\n", __func__);
103                 kfree(server->secmech.sdeschmacsha256);
104                 server->secmech.sdeschmacsha256 = NULL;
105                 crypto_free_shash(server->secmech.hmacsha256);
106                 crypto_free_shash(server->secmech.cmacaes);
107                 server->secmech.hmacsha256 = NULL;
108                 server->secmech.cmacaes = NULL;
109                 return -ENOMEM;
110         }
111         server->secmech.sdesccmacaes->shash.tfm = server->secmech.cmacaes;
112         server->secmech.sdesccmacaes->shash.flags = 0x0;
113
114         return 0;
115 }
116
117 static struct cifs_ses *
118 smb2_find_smb_ses(struct smb2_hdr *smb2hdr, struct TCP_Server_Info *server)
119 {
120         struct cifs_ses *ses;
121
122         spin_lock(&cifs_tcp_ses_lock);
123         list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
124                 if (ses->Suid != smb2hdr->SessionId)
125                         continue;
126                 spin_unlock(&cifs_tcp_ses_lock);
127                 return ses;
128         }
129         spin_unlock(&cifs_tcp_ses_lock);
130
131         return NULL;
132 }
133
134
135 int
136 smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
137 {
138         int i, rc;
139         unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
140         unsigned char *sigptr = smb2_signature;
141         struct kvec *iov = rqst->rq_iov;
142         int n_vec = rqst->rq_nvec;
143         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
144         struct cifs_ses *ses;
145
146         ses = smb2_find_smb_ses(smb2_pdu, server);
147         if (!ses) {
148                 cifs_dbg(VFS, "%s: Could not find session\n", __func__);
149                 return 0;
150         }
151
152         memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
153         memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
154
155         rc = smb2_crypto_shash_allocate(server);
156         if (rc) {
157                 cifs_dbg(VFS, "%s: shah256 alloc failed\n", __func__);
158                 return rc;
159         }
160
161         rc = crypto_shash_setkey(server->secmech.hmacsha256,
162                 ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
163         if (rc) {
164                 cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
165                 return rc;
166         }
167
168         rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
169         if (rc) {
170                 cifs_dbg(VFS, "%s: Could not init sha256", __func__);
171                 return rc;
172         }
173
174         for (i = 0; i < n_vec; i++) {
175                 if (iov[i].iov_len == 0)
176                         continue;
177                 if (iov[i].iov_base == NULL) {
178                         cifs_dbg(VFS, "null iovec entry\n");
179                         return -EIO;
180                 }
181                 /*
182                  * The first entry includes a length field (which does not get
183                  * signed that occupies the first 4 bytes before the header).
184                  */
185                 if (i == 0) {
186                         if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
187                                 break; /* nothing to sign or corrupt header */
188                         rc =
189                         crypto_shash_update(
190                                 &server->secmech.sdeschmacsha256->shash,
191                                 iov[i].iov_base + 4, iov[i].iov_len - 4);
192                 } else {
193                         rc =
194                         crypto_shash_update(
195                                 &server->secmech.sdeschmacsha256->shash,
196                                 iov[i].iov_base, iov[i].iov_len);
197                 }
198                 if (rc) {
199                         cifs_dbg(VFS, "%s: Could not update with payload\n",
200                                  __func__);
201                         return rc;
202                 }
203         }
204
205         /* now hash over the rq_pages array */
206         for (i = 0; i < rqst->rq_npages; i++) {
207                 struct kvec p_iov;
208
209                 cifs_rqst_page_to_kvec(rqst, i, &p_iov);
210                 crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
211                                         p_iov.iov_base, p_iov.iov_len);
212                 kunmap(rqst->rq_pages[i]);
213         }
214
215         rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
216                                 sigptr);
217         if (rc)
218                 cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
219
220         memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
221
222         return rc;
223 }
224
225 int
226 generate_smb3signingkey(struct cifs_ses *ses)
227 {
228         unsigned char zero = 0x0;
229         __u8 i[4] = {0, 0, 0, 1};
230         __u8 L[4] = {0, 0, 0, 128};
231         int rc = 0;
232         unsigned char prfhash[SMB2_HMACSHA256_SIZE];
233         unsigned char *hashptr = prfhash;
234
235         memset(prfhash, 0x0, SMB2_HMACSHA256_SIZE);
236         memset(ses->smb3signingkey, 0x0, SMB3_SIGNKEY_SIZE);
237
238         rc = smb3_crypto_shash_allocate(ses->server);
239         if (rc) {
240                 cifs_dbg(VFS, "%s: crypto alloc failed\n", __func__);
241                 goto smb3signkey_ret;
242         }
243
244         rc = crypto_shash_setkey(ses->server->secmech.hmacsha256,
245                 ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
246         if (rc) {
247                 cifs_dbg(VFS, "%s: Could not set with session key\n", __func__);
248                 goto smb3signkey_ret;
249         }
250
251         rc = crypto_shash_init(&ses->server->secmech.sdeschmacsha256->shash);
252         if (rc) {
253                 cifs_dbg(VFS, "%s: Could not init sign hmac\n", __func__);
254                 goto smb3signkey_ret;
255         }
256
257         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
258                                 i, 4);
259         if (rc) {
260                 cifs_dbg(VFS, "%s: Could not update with n\n", __func__);
261                 goto smb3signkey_ret;
262         }
263
264         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
265                                 "SMB2AESCMAC", 12);
266         if (rc) {
267                 cifs_dbg(VFS, "%s: Could not update with label\n", __func__);
268                 goto smb3signkey_ret;
269         }
270
271         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
272                                 &zero, 1);
273         if (rc) {
274                 cifs_dbg(VFS, "%s: Could not update with zero\n", __func__);
275                 goto smb3signkey_ret;
276         }
277
278         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
279                                 "SmbSign", 8);
280         if (rc) {
281                 cifs_dbg(VFS, "%s: Could not update with context\n", __func__);
282                 goto smb3signkey_ret;
283         }
284
285         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
286                                 L, 4);
287         if (rc) {
288                 cifs_dbg(VFS, "%s: Could not update with L\n", __func__);
289                 goto smb3signkey_ret;
290         }
291
292         rc = crypto_shash_final(&ses->server->secmech.sdeschmacsha256->shash,
293                                 hashptr);
294         if (rc) {
295                 cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
296                 goto smb3signkey_ret;
297         }
298
299         memcpy(ses->smb3signingkey, hashptr, SMB3_SIGNKEY_SIZE);
300
301 smb3signkey_ret:
302         return rc;
303 }
304
305 int
306 smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
307 {
308         int i;
309         int rc = 0;
310         unsigned char smb3_signature[SMB2_CMACAES_SIZE];
311         unsigned char *sigptr = smb3_signature;
312         struct kvec *iov = rqst->rq_iov;
313         int n_vec = rqst->rq_nvec;
314         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
315         struct cifs_ses *ses;
316
317         ses = smb2_find_smb_ses(smb2_pdu, server);
318         if (!ses) {
319                 cifs_dbg(VFS, "%s: Could not find session\n", __func__);
320                 return 0;
321         }
322
323         memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE);
324         memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
325
326         rc = crypto_shash_setkey(server->secmech.cmacaes,
327                 ses->smb3signingkey, SMB2_CMACAES_SIZE);
328
329         if (rc) {
330                 cifs_dbg(VFS, "%s: Could not set key for cmac aes\n", __func__);
331                 return rc;
332         }
333
334         /*
335          * we already allocate sdesccmacaes when we init smb3 signing key,
336          * so unlike smb2 case we do not have to check here if secmech are
337          * initialized
338          */
339         rc = crypto_shash_init(&server->secmech.sdesccmacaes->shash);
340         if (rc) {
341                 cifs_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
342                 return rc;
343         }
344
345         for (i = 0; i < n_vec; i++) {
346                 if (iov[i].iov_len == 0)
347                         continue;
348                 if (iov[i].iov_base == NULL) {
349                         cifs_dbg(VFS, "null iovec entry");
350                         return -EIO;
351                 }
352                 /*
353                  * The first entry includes a length field (which does not get
354                  * signed that occupies the first 4 bytes before the header).
355                  */
356                 if (i == 0) {
357                         if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
358                                 break; /* nothing to sign or corrupt header */
359                         rc =
360                         crypto_shash_update(
361                                 &server->secmech.sdesccmacaes->shash,
362                                 iov[i].iov_base + 4, iov[i].iov_len - 4);
363                 } else {
364                         rc =
365                         crypto_shash_update(
366                                 &server->secmech.sdesccmacaes->shash,
367                                 iov[i].iov_base, iov[i].iov_len);
368                 }
369                 if (rc) {
370                         cifs_dbg(VFS, "%s: Couldn't update cmac aes with payload\n",
371                                                         __func__);
372                         return rc;
373                 }
374         }
375
376         /* now hash over the rq_pages array */
377         for (i = 0; i < rqst->rq_npages; i++) {
378                 struct kvec p_iov;
379
380                 cifs_rqst_page_to_kvec(rqst, i, &p_iov);
381                 crypto_shash_update(&server->secmech.sdesccmacaes->shash,
382                                         p_iov.iov_base, p_iov.iov_len);
383                 kunmap(rqst->rq_pages[i]);
384         }
385
386         rc = crypto_shash_final(&server->secmech.sdesccmacaes->shash,
387                                                 sigptr);
388         if (rc)
389                 cifs_dbg(VFS, "%s: Could not generate cmac aes\n", __func__);
390
391         memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
392
393         return rc;
394 }
395
396 /* must be called with server->srv_mutex held */
397 static int
398 smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
399 {
400         int rc = 0;
401         struct smb2_hdr *smb2_pdu = rqst->rq_iov[0].iov_base;
402
403         if (!(smb2_pdu->Flags & SMB2_FLAGS_SIGNED) ||
404             server->tcpStatus == CifsNeedNegotiate)
405                 return rc;
406
407         if (!server->session_estab) {
408                 strncpy(smb2_pdu->Signature, "BSRSPYL", 8);
409                 return rc;
410         }
411
412         rc = server->ops->calc_signature(rqst, server);
413
414         return rc;
415 }
416
417 int
418 smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
419 {
420         unsigned int rc;
421         char server_response_sig[16];
422         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
423
424         if ((smb2_pdu->Command == SMB2_NEGOTIATE) ||
425             (smb2_pdu->Command == SMB2_SESSION_SETUP) ||
426             (smb2_pdu->Command == SMB2_OPLOCK_BREAK) ||
427             (!server->session_estab))
428                 return 0;
429
430         /*
431          * BB what if signatures are supposed to be on for session but
432          * server does not send one? BB
433          */
434
435         /* Do not need to verify session setups with signature "BSRSPYL " */
436         if (memcmp(smb2_pdu->Signature, "BSRSPYL ", 8) == 0)
437                 cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
438                          smb2_pdu->Command);
439
440         /*
441          * Save off the origiginal signature so we can modify the smb and check
442          * our calculated signature against what the server sent.
443          */
444         memcpy(server_response_sig, smb2_pdu->Signature, SMB2_SIGNATURE_SIZE);
445
446         memset(smb2_pdu->Signature, 0, SMB2_SIGNATURE_SIZE);
447
448         mutex_lock(&server->srv_mutex);
449         rc = server->ops->calc_signature(rqst, server);
450         mutex_unlock(&server->srv_mutex);
451
452         if (rc)
453                 return rc;
454
455         if (memcmp(server_response_sig, smb2_pdu->Signature,
456                    SMB2_SIGNATURE_SIZE))
457                 return -EACCES;
458         else
459                 return 0;
460 }
461
462 /*
463  * Set message id for the request. Should be called after wait_for_free_request
464  * and when srv_mutex is held.
465  */
466 static inline void
467 smb2_seq_num_into_buf(struct TCP_Server_Info *server, struct smb2_hdr *hdr)
468 {
469         hdr->MessageId = get_next_mid64(server);
470 }
471
472 static struct mid_q_entry *
473 smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
474                      struct TCP_Server_Info *server)
475 {
476         struct mid_q_entry *temp;
477
478         if (server == NULL) {
479                 cifs_dbg(VFS, "Null TCP session in smb2_mid_entry_alloc\n");
480                 return NULL;
481         }
482
483         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
484         if (temp == NULL)
485                 return temp;
486         else {
487                 memset(temp, 0, sizeof(struct mid_q_entry));
488                 temp->mid = smb_buffer->MessageId;      /* always LE */
489                 temp->pid = current->pid;
490                 temp->command = smb_buffer->Command;    /* Always LE */
491                 temp->when_alloc = jiffies;
492                 temp->server = server;
493
494                 /*
495                  * The default is for the mid to be synchronous, so the
496                  * default callback just wakes up the current task.
497                  */
498                 temp->callback = cifs_wake_up_task;
499                 temp->callback_data = current;
500         }
501
502         atomic_inc(&midCount);
503         temp->mid_state = MID_REQUEST_ALLOCATED;
504         return temp;
505 }
506
507 static int
508 smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
509                    struct mid_q_entry **mid)
510 {
511         if (ses->server->tcpStatus == CifsExiting)
512                 return -ENOENT;
513
514         if (ses->server->tcpStatus == CifsNeedReconnect) {
515                 cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
516                 return -EAGAIN;
517         }
518
519         if (ses->status == CifsNew) {
520                 if ((buf->Command != SMB2_SESSION_SETUP) &&
521                     (buf->Command != SMB2_NEGOTIATE))
522                         return -EAGAIN;
523                 /* else ok - we are setting up session */
524         }
525
526         if (ses->status == CifsExiting) {
527                 if (buf->Command != SMB2_LOGOFF)
528                         return -EAGAIN;
529                 /* else ok - we are shutting down the session */
530         }
531
532         *mid = smb2_mid_entry_alloc(buf, ses->server);
533         if (*mid == NULL)
534                 return -ENOMEM;
535         spin_lock(&GlobalMid_Lock);
536         list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
537         spin_unlock(&GlobalMid_Lock);
538         return 0;
539 }
540
541 int
542 smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
543                    bool log_error)
544 {
545         unsigned int len = get_rfc1002_length(mid->resp_buf);
546         struct kvec iov;
547         struct smb_rqst rqst = { .rq_iov = &iov,
548                                  .rq_nvec = 1 };
549
550         iov.iov_base = (char *)mid->resp_buf;
551         iov.iov_len = get_rfc1002_length(mid->resp_buf) + 4;
552
553         dump_smb(mid->resp_buf, min_t(u32, 80, len));
554         /* convert the length into a more usable form */
555         if (len > 24 && server->sign) {
556                 int rc;
557
558                 rc = smb2_verify_signature(&rqst, server);
559                 if (rc)
560                         cifs_dbg(VFS, "SMB signature verification returned error = %d\n",
561                                  rc);
562         }
563
564         return map_smb2_to_linux_error(mid->resp_buf, log_error);
565 }
566
567 struct mid_q_entry *
568 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
569 {
570         int rc;
571         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
572         struct mid_q_entry *mid;
573
574         smb2_seq_num_into_buf(ses->server, hdr);
575
576         rc = smb2_get_mid_entry(ses, hdr, &mid);
577         if (rc)
578                 return ERR_PTR(rc);
579         rc = smb2_sign_rqst(rqst, ses->server);
580         if (rc) {
581                 cifs_delete_mid(mid);
582                 return ERR_PTR(rc);
583         }
584         return mid;
585 }
586
587 struct mid_q_entry *
588 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
589 {
590         int rc;
591         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
592         struct mid_q_entry *mid;
593
594         smb2_seq_num_into_buf(server, hdr);
595
596         mid = smb2_mid_entry_alloc(hdr, server);
597         if (mid == NULL)
598                 return ERR_PTR(-ENOMEM);
599
600         rc = smb2_sign_rqst(rqst, server);
601         if (rc) {
602                 DeleteMidQEntry(mid);
603                 return ERR_PTR(rc);
604         }
605
606         return mid;
607 }