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_mid(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 != CifsGood) {
 520                 /* check if SMB2 session is bad because we are setting it up */
 521                 if ((buf->Command != SMB2_SESSION_SETUP) &&
 522                     (buf->Command != SMB2_NEGOTIATE))
 523                         return -EAGAIN;
 524                 /* else ok - we are setting up session */
 525         }
 526         *mid = smb2_mid_entry_alloc(buf, ses->server);
 527         if (*mid == NULL)
 528                 return -ENOMEM;
 529         spin_lock(&GlobalMid_Lock);
 530         list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
 531         spin_unlock(&GlobalMid_Lock);
 532         return 0;
 533 }
 534
 535 int
 536 smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 537                    bool log_error)
 538 {
 539         unsigned int len = get_rfc1002_length(mid->resp_buf);
 540         struct kvec iov;
 541         struct smb_rqst rqst = { .rq_iov = &iov,
 542                                  .rq_nvec = 1 };
 543
 544         iov.iov_base = (char *)mid->resp_buf;
 545         iov.iov_len = get_rfc1002_length(mid->resp_buf) + 4;
 546
 547         dump_smb(mid->resp_buf, min_t(u32, 80, len));
 548         /* convert the length into a more usable form */
 549         if (len > 24 && server->sign) {
 550                 int rc;
 551
 552                 rc = smb2_verify_signature(&rqst, server);
 553                 if (rc)
 554                         cifs_dbg(VFS, "SMB signature verification returned error = %d\n",
 555                                  rc);
 556         }
 557
 558         return map_smb2_to_linux_error(mid->resp_buf, log_error);
 559 }
 560
 561 struct mid_q_entry *
 562 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
 563 {
 564         int rc;
 565         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 566         struct mid_q_entry *mid;
 567
 568         smb2_seq_num_into_buf(ses->server, hdr);
 569
 570         rc = smb2_get_mid_entry(ses, hdr, &mid);
 571         if (rc)
 572                 return ERR_PTR(rc);
 573         rc = smb2_sign_rqst(rqst, ses->server);
 574         if (rc) {
 575                 cifs_delete_mid(mid);
 576                 return ERR_PTR(rc);
 577         }
 578         return mid;
 579 }
 580
 581 struct mid_q_entry *
 582 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 583 {
 584         int rc;
 585         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 586         struct mid_q_entry *mid;
 587
 588         smb2_seq_num_into_buf(server, hdr);
 589
 590         mid = smb2_mid_entry_alloc(hdr, server);
 591         if (mid == NULL)
 592                 return ERR_PTR(-ENOMEM);
 593
 594         rc = smb2_sign_rqst(rqst, server);
 595         if (rc) {
 596                 DeleteMidQEntry(mid);
 597                 return ERR_PTR(rc);
 598         }
 599
 600         return mid;
 601 }