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
 118 int
 119 smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 120 {
 121         int i, rc;
 122         unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
 123         unsigned char *sigptr = smb2_signature;
 124         struct kvec *iov = rqst->rq_iov;
 125         int n_vec = rqst->rq_nvec;
 126         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
 127
 128         memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
 129         memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
 130
 131         rc = smb2_crypto_shash_allocate(server);
 132         if (rc) {
 133                 cifs_dbg(VFS, "%s: shah256 alloc failed\n", __func__);
 134                 return rc;
 135         }
 136
 137         rc = crypto_shash_setkey(server->secmech.hmacsha256,
 138                 server->session_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
 139         if (rc) {
 140                 cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
 141                 return rc;
 142         }
 143
 144         rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
 145         if (rc) {
 146                 cifs_dbg(VFS, "%s: Could not init sha256", __func__);
 147                 return rc;
 148         }
 149
 150         for (i = 0; i < n_vec; i++) {
 151                 if (iov[i].iov_len == 0)
 152                         continue;
 153                 if (iov[i].iov_base == NULL) {
 154                         cifs_dbg(VFS, "null iovec entry\n");
 155                         return -EIO;
 156                 }
 157                 /*
 158                  * The first entry includes a length field (which does not get
 159                  * signed that occupies the first 4 bytes before the header).
 160                  */
 161                 if (i == 0) {
 162                         if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
 163                                 break; /* nothing to sign or corrupt header */
 164                         rc =
 165                         crypto_shash_update(
 166                                 &server->secmech.sdeschmacsha256->shash,
 167                                 iov[i].iov_base + 4, iov[i].iov_len - 4);
 168                 } else {
 169                         rc =
 170                         crypto_shash_update(
 171                                 &server->secmech.sdeschmacsha256->shash,
 172                                 iov[i].iov_base, iov[i].iov_len);
 173                 }
 174                 if (rc) {
 175                         cifs_dbg(VFS, "%s: Could not update with payload\n",
 176                                  __func__);
 177                         return rc;
 178                 }
 179         }
 180
 181         /* now hash over the rq_pages array */
 182         for (i = 0; i < rqst->rq_npages; i++) {
 183                 struct kvec p_iov;
 184
 185                 cifs_rqst_page_to_kvec(rqst, i, &p_iov);
 186                 crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
 187                                         p_iov.iov_base, p_iov.iov_len);
 188                 kunmap(rqst->rq_pages[i]);
 189         }
 190
 191         rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
 192                                 sigptr);
 193         if (rc)
 194                 cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
 195
 196         memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 197
 198         return rc;
 199 }
 200
 201 void
 202 generate_smb3signingkey(struct TCP_Server_Info *server)
 203 {
 204         unsigned char zero = 0x0;
 205         __u8 i[4] = {0, 0, 0, 1};
 206         __u8 L[4] = {0, 0, 0, 128};
 207         int rc = 0;
 208         unsigned char prfhash[SMB2_HMACSHA256_SIZE];
 209         unsigned char *hashptr = prfhash;
 210
 211         memset(prfhash, 0x0, SMB2_HMACSHA256_SIZE);
 212         memset(server->smb3signingkey, 0x0, SMB3_SIGNKEY_SIZE);
 213
 214         rc = smb3_crypto_shash_allocate(server);
 215         if (rc) {
 216                 cifs_dbg(VFS, "%s: crypto alloc failed\n", __func__);
 217                 goto smb3signkey_ret;
 218         }
 219
 220         rc = crypto_shash_setkey(server->secmech.hmacsha256,
 221                 server->session_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
 222         if (rc) {
 223                 cifs_dbg(VFS, "%s: Could not set with session key\n", __func__);
 224                 goto smb3signkey_ret;
 225         }
 226
 227         rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
 228         if (rc) {
 229                 cifs_dbg(VFS, "%s: Could not init sign hmac\n", __func__);
 230                 goto smb3signkey_ret;
 231         }
 232
 233         rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
 234                                 i, 4);
 235         if (rc) {
 236                 cifs_dbg(VFS, "%s: Could not update with n\n", __func__);
 237                 goto smb3signkey_ret;
 238         }
 239
 240         rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
 241                                 "SMB2AESCMAC", 12);
 242         if (rc) {
 243                 cifs_dbg(VFS, "%s: Could not update with label\n", __func__);
 244                 goto smb3signkey_ret;
 245         }
 246
 247         rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
 248                                 &zero, 1);
 249         if (rc) {
 250                 cifs_dbg(VFS, "%s: Could not update with zero\n", __func__);
 251                 goto smb3signkey_ret;
 252         }
 253
 254         rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
 255                                 "SmbSign", 8);
 256         if (rc) {
 257                 cifs_dbg(VFS, "%s: Could not update with context\n", __func__);
 258                 goto smb3signkey_ret;
 259         }
 260
 261         rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
 262                                 L, 4);
 263         if (rc) {
 264                 cifs_dbg(VFS, "%s: Could not update with L\n", __func__);
 265                 goto smb3signkey_ret;
 266         }
 267
 268         rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
 269                                 hashptr);
 270         if (rc) {
 271                 cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
 272                 goto smb3signkey_ret;
 273         }
 274
 275         memcpy(server->smb3signingkey, hashptr, SMB3_SIGNKEY_SIZE);
 276
 277 smb3signkey_ret:
 278         return;
 279 }
 280
 281 int
 282 smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 283 {
 284         int i, rc;
 285         unsigned char smb3_signature[SMB2_CMACAES_SIZE];
 286         unsigned char *sigptr = smb3_signature;
 287         struct kvec *iov = rqst->rq_iov;
 288         int n_vec = rqst->rq_nvec;
 289         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
 290
 291         memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE);
 292         memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
 293
 294         rc = crypto_shash_setkey(server->secmech.cmacaes,
 295                 server->smb3signingkey, SMB2_CMACAES_SIZE);
 296         if (rc) {
 297                 cifs_dbg(VFS, "%s: Could not set key for cmac aes\n", __func__);
 298                 return rc;
 299         }
 300
 301         /*
 302          * we already allocate sdesccmacaes when we init smb3 signing key,
 303          * so unlike smb2 case we do not have to check here if secmech are
 304          * initialized
 305          */
 306         rc = crypto_shash_init(&server->secmech.sdesccmacaes->shash);
 307         if (rc) {
 308                 cifs_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
 309                 return rc;
 310         }
 311
 312         for (i = 0; i < n_vec; i++) {
 313                 if (iov[i].iov_len == 0)
 314                         continue;
 315                 if (iov[i].iov_base == NULL) {
 316                         cifs_dbg(VFS, "null iovec entry");
 317                         return -EIO;
 318                 }
 319                 /*
 320                  * The first entry includes a length field (which does not get
 321                  * signed that occupies the first 4 bytes before the header).
 322                  */
 323                 if (i == 0) {
 324                         if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
 325                                 break; /* nothing to sign or corrupt header */
 326                         rc =
 327                         crypto_shash_update(
 328                                 &server->secmech.sdesccmacaes->shash,
 329                                 iov[i].iov_base + 4, iov[i].iov_len - 4);
 330                 } else {
 331                         rc =
 332                         crypto_shash_update(
 333                                 &server->secmech.sdesccmacaes->shash,
 334                                 iov[i].iov_base, iov[i].iov_len);
 335                 }
 336                 if (rc) {
 337                         cifs_dbg(VFS, "%s: Couldn't update cmac aes with payload\n",
 338                                                         __func__);
 339                         return rc;
 340                 }
 341         }
 342
 343         /* now hash over the rq_pages array */
 344         for (i = 0; i < rqst->rq_npages; i++) {
 345                 struct kvec p_iov;
 346
 347                 cifs_rqst_page_to_kvec(rqst, i, &p_iov);
 348                 crypto_shash_update(&server->secmech.sdesccmacaes->shash,
 349                                         p_iov.iov_base, p_iov.iov_len);
 350                 kunmap(rqst->rq_pages[i]);
 351         }
 352
 353         rc = crypto_shash_final(&server->secmech.sdesccmacaes->shash,
 354                                                 sigptr);
 355         if (rc)
 356                 cifs_dbg(VFS, "%s: Could not generate cmac aes\n", __func__);
 357
 358         memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 359
 360         return rc;
 361 }
 362
 363 /* must be called with server->srv_mutex held */
 364 static int
 365 smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 366 {
 367         int rc = 0;
 368         struct smb2_hdr *smb2_pdu = rqst->rq_iov[0].iov_base;
 369
 370         if (!(smb2_pdu->Flags & SMB2_FLAGS_SIGNED) ||
 371             server->tcpStatus == CifsNeedNegotiate)
 372                 return rc;
 373
 374         if (!server->session_estab) {
 375                 strncpy(smb2_pdu->Signature, "BSRSPYL", 8);
 376                 return rc;
 377         }
 378
 379         rc = server->ops->calc_signature(rqst, server);
 380
 381         return rc;
 382 }
 383
 384 int
 385 smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 386 {
 387         unsigned int rc;
 388         char server_response_sig[16];
 389         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 390
 391         if ((smb2_pdu->Command == SMB2_NEGOTIATE) ||
 392             (smb2_pdu->Command == SMB2_OPLOCK_BREAK) ||
 393             (!server->session_estab))
 394                 return 0;
 395
 396         /*
 397          * BB what if signatures are supposed to be on for session but
 398          * server does not send one? BB
 399          */
 400
 401         /* Do not need to verify session setups with signature "BSRSPYL " */
 402         if (memcmp(smb2_pdu->Signature, "BSRSPYL ", 8) == 0)
 403                 cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
 404                          smb2_pdu->Command);
 405
 406         /*
 407          * Save off the origiginal signature so we can modify the smb and check
 408          * our calculated signature against what the server sent.
 409          */
 410         memcpy(server_response_sig, smb2_pdu->Signature, SMB2_SIGNATURE_SIZE);
 411
 412         memset(smb2_pdu->Signature, 0, SMB2_SIGNATURE_SIZE);
 413
 414         mutex_lock(&server->srv_mutex);
 415         rc = server->ops->calc_signature(rqst, server);
 416         mutex_unlock(&server->srv_mutex);
 417
 418         if (rc)
 419                 return rc;
 420
 421         if (memcmp(server_response_sig, smb2_pdu->Signature,
 422                    SMB2_SIGNATURE_SIZE))
 423                 return -EACCES;
 424         else
 425                 return 0;
 426 }
 427
 428 /*
 429  * Set message id for the request. Should be called after wait_for_free_request
 430  * and when srv_mutex is held.
 431  */
 432 static inline void
 433 smb2_seq_num_into_buf(struct TCP_Server_Info *server, struct smb2_hdr *hdr)
 434 {
 435         hdr->MessageId = get_next_mid(server);
 436 }
 437
 438 static struct mid_q_entry *
 439 smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
 440                      struct TCP_Server_Info *server)
 441 {
 442         struct mid_q_entry *temp;
 443
 444         if (server == NULL) {
 445                 cifs_dbg(VFS, "Null TCP session in smb2_mid_entry_alloc\n");
 446                 return NULL;
 447         }
 448
 449         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
 450         if (temp == NULL)
 451                 return temp;
 452         else {
 453                 memset(temp, 0, sizeof(struct mid_q_entry));
 454                 temp->mid = smb_buffer->MessageId;      /* always LE */
 455                 temp->pid = current->pid;
 456                 temp->command = smb_buffer->Command;    /* Always LE */
 457                 temp->when_alloc = jiffies;
 458                 temp->server = server;
 459
 460                 /*
 461                  * The default is for the mid to be synchronous, so the
 462                  * default callback just wakes up the current task.
 463                  */
 464                 temp->callback = cifs_wake_up_task;
 465                 temp->callback_data = current;
 466         }
 467
 468         atomic_inc(&midCount);
 469         temp->mid_state = MID_REQUEST_ALLOCATED;
 470         return temp;
 471 }
 472
 473 static int
 474 smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
 475                    struct mid_q_entry **mid)
 476 {
 477         if (ses->server->tcpStatus == CifsExiting)
 478                 return -ENOENT;
 479
 480         if (ses->server->tcpStatus == CifsNeedReconnect) {
 481                 cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
 482                 return -EAGAIN;
 483         }
 484
 485         if (ses->status != CifsGood) {
 486                 /* check if SMB2 session is bad because we are setting it up */
 487                 if ((buf->Command != SMB2_SESSION_SETUP) &&
 488                     (buf->Command != SMB2_NEGOTIATE))
 489                         return -EAGAIN;
 490                 /* else ok - we are setting up session */
 491         }
 492         *mid = smb2_mid_entry_alloc(buf, ses->server);
 493         if (*mid == NULL)
 494                 return -ENOMEM;
 495         spin_lock(&GlobalMid_Lock);
 496         list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
 497         spin_unlock(&GlobalMid_Lock);
 498         return 0;
 499 }
 500
 501 int
 502 smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 503                    bool log_error)
 504 {
 505         unsigned int len = get_rfc1002_length(mid->resp_buf);
 506         struct kvec iov;
 507         struct smb_rqst rqst = { .rq_iov = &iov,
 508                                  .rq_nvec = 1 };
 509
 510         iov.iov_base = (char *)mid->resp_buf;
 511         iov.iov_len = get_rfc1002_length(mid->resp_buf) + 4;
 512
 513         dump_smb(mid->resp_buf, min_t(u32, 80, len));
 514         /* convert the length into a more usable form */
 515         if (len > 24 && server->sign) {
 516                 int rc;
 517
 518                 rc = smb2_verify_signature(&rqst, server);
 519                 if (rc)
 520                         cifs_dbg(VFS, "SMB signature verification returned error = %d\n",
 521                                  rc);
 522         }
 523
 524         return map_smb2_to_linux_error(mid->resp_buf, log_error);
 525 }
 526
 527 struct mid_q_entry *
 528 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
 529 {
 530         int rc;
 531         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 532         struct mid_q_entry *mid;
 533
 534         smb2_seq_num_into_buf(ses->server, hdr);
 535
 536         rc = smb2_get_mid_entry(ses, hdr, &mid);
 537         if (rc)
 538                 return ERR_PTR(rc);
 539         rc = smb2_sign_rqst(rqst, ses->server);
 540         if (rc) {
 541                 cifs_delete_mid(mid);
 542                 return ERR_PTR(rc);
 543         }
 544         return mid;
 545 }
 546
 547 struct mid_q_entry *
 548 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 549 {
 550         int rc;
 551         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 552         struct mid_q_entry *mid;
 553
 554         smb2_seq_num_into_buf(server, hdr);
 555
 556         mid = smb2_mid_entry_alloc(hdr, server);
 557         if (mid == NULL)
 558                 return ERR_PTR(-ENOMEM);
 559
 560         rc = smb2_sign_rqst(rqst, server);
 561         if (rc) {
 562                 DeleteMidQEntry(mid);
 563                 return ERR_PTR(rc);
 564         }
 565
 566         return mid;
 567 }