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_sync_hdr *shdr, 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 != shdr->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 int
 135 smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 136 {
 137         int rc;
 138         unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
 139         unsigned char *sigptr = smb2_signature;
 140         struct kvec *iov = rqst->rq_iov;
 141         struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)iov[1].iov_base;
 142         struct cifs_ses *ses;
 143
 144         ses = smb2_find_smb_ses(shdr, server);
 145         if (!ses) {
 146                 cifs_dbg(VFS, "%s: Could not find session\n", __func__);
 147                 return 0;
 148         }
 149
 150         memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
 151         memset(shdr->Signature, 0x0, SMB2_SIGNATURE_SIZE);
 152
 153         rc = smb2_crypto_shash_allocate(server);
 154         if (rc) {
 155                 cifs_dbg(VFS, "%s: shah256 alloc failed\n", __func__);
 156                 return rc;
 157         }
 158
 159         rc = crypto_shash_setkey(server->secmech.hmacsha256,
 160                 ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
 161         if (rc) {
 162                 cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
 163                 return rc;
 164         }
 165
 166         rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
 167         if (rc) {
 168                 cifs_dbg(VFS, "%s: Could not init sha256", __func__);
 169                 return rc;
 170         }
 171
 172         rc = __cifs_calc_signature(rqst, server, sigptr,
 173                 &server->secmech.sdeschmacsha256->shash);
 174
 175         if (!rc)
 176                 memcpy(shdr->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 177
 178         return rc;
 179 }
 180
 181 static int generate_key(struct cifs_ses *ses, struct kvec label,
 182                         struct kvec context, __u8 *key, unsigned int key_size)
 183 {
 184         unsigned char zero = 0x0;
 185         __u8 i[4] = {0, 0, 0, 1};
 186         __u8 L[4] = {0, 0, 0, 128};
 187         int rc = 0;
 188         unsigned char prfhash[SMB2_HMACSHA256_SIZE];
 189         unsigned char *hashptr = prfhash;
 190
 191         memset(prfhash, 0x0, SMB2_HMACSHA256_SIZE);
 192         memset(key, 0x0, key_size);
 193
 194         rc = smb3_crypto_shash_allocate(ses->server);
 195         if (rc) {
 196                 cifs_dbg(VFS, "%s: crypto alloc failed\n", __func__);
 197                 goto smb3signkey_ret;
 198         }
 199
 200         rc = crypto_shash_setkey(ses->server->secmech.hmacsha256,
 201                 ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
 202         if (rc) {
 203                 cifs_dbg(VFS, "%s: Could not set with session key\n", __func__);
 204                 goto smb3signkey_ret;
 205         }
 206
 207         rc = crypto_shash_init(&ses->server->secmech.sdeschmacsha256->shash);
 208         if (rc) {
 209                 cifs_dbg(VFS, "%s: Could not init sign hmac\n", __func__);
 210                 goto smb3signkey_ret;
 211         }
 212
 213         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 214                                 i, 4);
 215         if (rc) {
 216                 cifs_dbg(VFS, "%s: Could not update with n\n", __func__);
 217                 goto smb3signkey_ret;
 218         }
 219
 220         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 221                                 label.iov_base, label.iov_len);
 222         if (rc) {
 223                 cifs_dbg(VFS, "%s: Could not update with label\n", __func__);
 224                 goto smb3signkey_ret;
 225         }
 226
 227         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 228                                 &zero, 1);
 229         if (rc) {
 230                 cifs_dbg(VFS, "%s: Could not update with zero\n", __func__);
 231                 goto smb3signkey_ret;
 232         }
 233
 234         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 235                                 context.iov_base, context.iov_len);
 236         if (rc) {
 237                 cifs_dbg(VFS, "%s: Could not update with context\n", __func__);
 238                 goto smb3signkey_ret;
 239         }
 240
 241         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 242                                 L, 4);
 243         if (rc) {
 244                 cifs_dbg(VFS, "%s: Could not update with L\n", __func__);
 245                 goto smb3signkey_ret;
 246         }
 247
 248         rc = crypto_shash_final(&ses->server->secmech.sdeschmacsha256->shash,
 249                                 hashptr);
 250         if (rc) {
 251                 cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
 252                 goto smb3signkey_ret;
 253         }
 254
 255         memcpy(key, hashptr, key_size);
 256
 257 smb3signkey_ret:
 258         return rc;
 259 }
 260
 261 struct derivation {
 262         struct kvec label;
 263         struct kvec context;
 264 };
 265
 266 struct derivation_triplet {
 267         struct derivation signing;
 268         struct derivation encryption;
 269         struct derivation decryption;
 270 };
 271
 272 static int
 273 generate_smb3signingkey(struct cifs_ses *ses,
 274                         const struct derivation_triplet *ptriplet)
 275 {
 276         int rc;
 277
 278         rc = generate_key(ses, ptriplet->signing.label,
 279                           ptriplet->signing.context, ses->smb3signingkey,
 280                           SMB3_SIGN_KEY_SIZE);
 281         if (rc)
 282                 return rc;
 283
 284         rc = generate_key(ses, ptriplet->encryption.label,
 285                           ptriplet->encryption.context, ses->smb3encryptionkey,
 286                           SMB3_SIGN_KEY_SIZE);
 287         if (rc)
 288                 return rc;
 289
 290         return generate_key(ses, ptriplet->decryption.label,
 291                             ptriplet->decryption.context,
 292                             ses->smb3decryptionkey, SMB3_SIGN_KEY_SIZE);
 293 }
 294
 295 int
 296 generate_smb30signingkey(struct cifs_ses *ses)
 297
 298 {
 299         struct derivation_triplet triplet;
 300         struct derivation *d;
 301
 302         d = &triplet.signing;
 303         d->label.iov_base = "SMB2AESCMAC";
 304         d->label.iov_len = 12;
 305         d->context.iov_base = "SmbSign";
 306         d->context.iov_len = 8;
 307
 308         d = &triplet.encryption;
 309         d->label.iov_base = "SMB2AESCCM";
 310         d->label.iov_len = 11;
 311         d->context.iov_base = "ServerIn ";
 312         d->context.iov_len = 10;
 313
 314         d = &triplet.decryption;
 315         d->label.iov_base = "SMB2AESCCM";
 316         d->label.iov_len = 11;
 317         d->context.iov_base = "ServerOut";
 318         d->context.iov_len = 10;
 319
 320         return generate_smb3signingkey(ses, &triplet);
 321 }
 322
 323 int
 324 generate_smb311signingkey(struct cifs_ses *ses)
 325
 326 {
 327         struct derivation_triplet triplet;
 328         struct derivation *d;
 329
 330         d = &triplet.signing;
 331         d->label.iov_base = "SMB2AESCMAC";
 332         d->label.iov_len = 12;
 333         d->context.iov_base = "SmbSign";
 334         d->context.iov_len = 8;
 335
 336         d = &triplet.encryption;
 337         d->label.iov_base = "SMB2AESCCM";
 338         d->label.iov_len = 11;
 339         d->context.iov_base = "ServerIn ";
 340         d->context.iov_len = 10;
 341
 342         d = &triplet.decryption;
 343         d->label.iov_base = "SMB2AESCCM";
 344         d->label.iov_len = 11;
 345         d->context.iov_base = "ServerOut";
 346         d->context.iov_len = 10;
 347
 348         return generate_smb3signingkey(ses, &triplet);
 349 }
 350
 351 int
 352 smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 353 {
 354         int rc = 0;
 355         unsigned char smb3_signature[SMB2_CMACAES_SIZE];
 356         unsigned char *sigptr = smb3_signature;
 357         struct kvec *iov = rqst->rq_iov;
 358         struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)iov[1].iov_base;
 359         struct cifs_ses *ses;
 360
 361         ses = smb2_find_smb_ses(shdr, server);
 362         if (!ses) {
 363                 cifs_dbg(VFS, "%s: Could not find session\n", __func__);
 364                 return 0;
 365         }
 366
 367         memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE);
 368         memset(shdr->Signature, 0x0, SMB2_SIGNATURE_SIZE);
 369
 370         rc = crypto_shash_setkey(server->secmech.cmacaes,
 371                 ses->smb3signingkey, SMB2_CMACAES_SIZE);
 372
 373         if (rc) {
 374                 cifs_dbg(VFS, "%s: Could not set key for cmac aes\n", __func__);
 375                 return rc;
 376         }
 377
 378         /*
 379          * we already allocate sdesccmacaes when we init smb3 signing key,
 380          * so unlike smb2 case we do not have to check here if secmech are
 381          * initialized
 382          */
 383         rc = crypto_shash_init(&server->secmech.sdesccmacaes->shash);
 384         if (rc) {
 385                 cifs_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
 386                 return rc;
 387         }
 388
 389         rc = __cifs_calc_signature(rqst, server, sigptr,
 390                                    &server->secmech.sdesccmacaes->shash);
 391
 392         if (!rc)
 393                 memcpy(shdr->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 394
 395         return rc;
 396 }
 397
 398 /* must be called with server->srv_mutex held */
 399 static int
 400 smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 401 {
 402         int rc = 0;
 403         struct smb2_sync_hdr *shdr =
 404                         (struct smb2_sync_hdr *)rqst->rq_iov[1].iov_base;
 405
 406         if (!(shdr->Flags & SMB2_FLAGS_SIGNED) ||
 407             server->tcpStatus == CifsNeedNegotiate)
 408                 return rc;
 409
 410         if (!server->session_estab) {
 411                 strncpy(shdr->Signature, "BSRSPYL", 8);
 412                 return rc;
 413         }
 414
 415         rc = server->ops->calc_signature(rqst, server);
 416
 417         return rc;
 418 }
 419
 420 int
 421 smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 422 {
 423         unsigned int rc;
 424         char server_response_sig[16];
 425         struct smb2_sync_hdr *shdr =
 426                         (struct smb2_sync_hdr *)rqst->rq_iov[1].iov_base;
 427
 428         if ((shdr->Command == SMB2_NEGOTIATE) ||
 429             (shdr->Command == SMB2_SESSION_SETUP) ||
 430             (shdr->Command == SMB2_OPLOCK_BREAK) ||
 431             (!server->session_estab))
 432                 return 0;
 433
 434         /*
 435          * BB what if signatures are supposed to be on for session but
 436          * server does not send one? BB
 437          */
 438
 439         /* Do not need to verify session setups with signature "BSRSPYL " */
 440         if (memcmp(shdr->Signature, "BSRSPYL ", 8) == 0)
 441                 cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
 442                          shdr->Command);
 443
 444         /*
 445          * Save off the origiginal signature so we can modify the smb and check
 446          * our calculated signature against what the server sent.
 447          */
 448         memcpy(server_response_sig, shdr->Signature, SMB2_SIGNATURE_SIZE);
 449
 450         memset(shdr->Signature, 0, SMB2_SIGNATURE_SIZE);
 451
 452         mutex_lock(&server->srv_mutex);
 453         rc = server->ops->calc_signature(rqst, server);
 454         mutex_unlock(&server->srv_mutex);
 455
 456         if (rc)
 457                 return rc;
 458
 459         if (memcmp(server_response_sig, shdr->Signature, SMB2_SIGNATURE_SIZE))
 460                 return -EACCES;
 461         else
 462                 return 0;
 463 }
 464
 465 /*
 466  * Set message id for the request. Should be called after wait_for_free_request
 467  * and when srv_mutex is held.
 468  */
 469 static inline void
 470 smb2_seq_num_into_buf(struct TCP_Server_Info *server,
 471                       struct smb2_sync_hdr *shdr)
 472 {
 473         unsigned int i, num = le16_to_cpu(shdr->CreditCharge);
 474
 475         shdr->MessageId = get_next_mid64(server);
 476         /* skip message numbers according to CreditCharge field */
 477         for (i = 1; i < num; i++)
 478                 get_next_mid(server);
 479 }
 480
 481 static struct mid_q_entry *
 482 smb2_mid_entry_alloc(const struct smb2_sync_hdr *shdr,
 483                      struct TCP_Server_Info *server)
 484 {
 485         struct mid_q_entry *temp;
 486
 487         if (server == NULL) {
 488                 cifs_dbg(VFS, "Null TCP session in smb2_mid_entry_alloc\n");
 489                 return NULL;
 490         }
 491
 492         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
 493         if (temp == NULL)
 494                 return temp;
 495         else {
 496                 memset(temp, 0, sizeof(struct mid_q_entry));
 497                 temp->mid = le64_to_cpu(shdr->MessageId);
 498                 temp->pid = current->pid;
 499                 temp->command = shdr->Command; /* Always LE */
 500                 temp->when_alloc = jiffies;
 501                 temp->server = server;
 502
 503                 /*
 504                  * The default is for the mid to be synchronous, so the
 505                  * default callback just wakes up the current task.
 506                  */
 507                 temp->callback = cifs_wake_up_task;
 508                 temp->callback_data = current;
 509         }
 510
 511         atomic_inc(&midCount);
 512         temp->mid_state = MID_REQUEST_ALLOCATED;
 513         return temp;
 514 }
 515
 516 static int
 517 smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_sync_hdr *shdr,
 518                    struct mid_q_entry **mid)
 519 {
 520         if (ses->server->tcpStatus == CifsExiting)
 521                 return -ENOENT;
 522
 523         if (ses->server->tcpStatus == CifsNeedReconnect) {
 524                 cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
 525                 return -EAGAIN;
 526         }
 527
 528         if (ses->status == CifsNew) {
 529                 if ((shdr->Command != SMB2_SESSION_SETUP) &&
 530                     (shdr->Command != SMB2_NEGOTIATE))
 531                         return -EAGAIN;
 532                 /* else ok - we are setting up session */
 533         }
 534
 535         if (ses->status == CifsExiting) {
 536                 if (shdr->Command != SMB2_LOGOFF)
 537                         return -EAGAIN;
 538                 /* else ok - we are shutting down the session */
 539         }
 540
 541         *mid = smb2_mid_entry_alloc(shdr, ses->server);
 542         if (*mid == NULL)
 543                 return -ENOMEM;
 544         spin_lock(&GlobalMid_Lock);
 545         list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
 546         spin_unlock(&GlobalMid_Lock);
 547         return 0;
 548 }
 549
 550 int
 551 smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 552                    bool log_error)
 553 {
 554         unsigned int len = get_rfc1002_length(mid->resp_buf);
 555         struct kvec iov[2];
 556         struct smb_rqst rqst = { .rq_iov = iov,
 557                                  .rq_nvec = 2 };
 558
 559         iov[0].iov_base = (char *)mid->resp_buf;
 560         iov[0].iov_len = 4;
 561         iov[1].iov_base = (char *)mid->resp_buf + 4;
 562         iov[1].iov_len = len;
 563
 564         dump_smb(mid->resp_buf, min_t(u32, 80, len));
 565         /* convert the length into a more usable form */
 566         if (len > 24 && server->sign) {
 567                 int rc;
 568
 569                 rc = smb2_verify_signature(&rqst, server);
 570                 if (rc)
 571                         cifs_dbg(VFS, "SMB signature verification returned error = %d\n",
 572                                  rc);
 573         }
 574
 575         return map_smb2_to_linux_error(mid->resp_buf, log_error);
 576 }
 577
 578 struct mid_q_entry *
 579 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
 580 {
 581         int rc;
 582         struct smb2_sync_hdr *shdr =
 583                         (struct smb2_sync_hdr *)rqst->rq_iov[1].iov_base;
 584         struct mid_q_entry *mid;
 585
 586         smb2_seq_num_into_buf(ses->server, shdr);
 587
 588         rc = smb2_get_mid_entry(ses, shdr, &mid);
 589         if (rc)
 590                 return ERR_PTR(rc);
 591         rc = smb2_sign_rqst(rqst, ses->server);
 592         if (rc) {
 593                 cifs_delete_mid(mid);
 594                 return ERR_PTR(rc);
 595         }
 596         return mid;
 597 }
 598
 599 struct mid_q_entry *
 600 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 601 {
 602         int rc;
 603         struct smb2_sync_hdr *shdr =
 604                         (struct smb2_sync_hdr *)rqst->rq_iov[1].iov_base;
 605         struct mid_q_entry *mid;
 606
 607         smb2_seq_num_into_buf(server, shdr);
 608
 609         mid = smb2_mid_entry_alloc(shdr, server);
 610         if (mid == NULL)
 611                 return ERR_PTR(-ENOMEM);
 612
 613         rc = smb2_sign_rqst(rqst, server);
 614         if (rc) {
 615                 DeleteMidQEntry(mid);
 616                 return ERR_PTR(rc);
 617         }
 618
 619         return mid;
 620 }