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 rc;
 139         unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
 140         unsigned char *sigptr = smb2_signature;
 141         struct kvec *iov = rqst->rq_iov;
 142         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
 143         struct cifs_ses *ses;
 144
 145         ses = smb2_find_smb_ses(smb2_pdu, server);
 146         if (!ses) {
 147                 cifs_dbg(VFS, "%s: Could not find session\n", __func__);
 148                 return 0;
 149         }
 150
 151         memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
 152         memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
 153
 154         rc = smb2_crypto_shash_allocate(server);
 155         if (rc) {
 156                 cifs_dbg(VFS, "%s: shah256 alloc failed\n", __func__);
 157                 return rc;
 158         }
 159
 160         rc = crypto_shash_setkey(server->secmech.hmacsha256,
 161                 ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
 162         if (rc) {
 163                 cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
 164                 return rc;
 165         }
 166
 167         rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
 168         if (rc) {
 169                 cifs_dbg(VFS, "%s: Could not init sha256", __func__);
 170                 return rc;
 171         }
 172
 173         rc = __cifs_calc_signature(rqst, server, sigptr,
 174                 &server->secmech.sdeschmacsha256->shash);
 175
 176         if (!rc)
 177                 memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 178
 179         return rc;
 180 }
 181
 182 static int generate_key(struct cifs_ses *ses, struct kvec label,
 183                         struct kvec context, __u8 *key, unsigned int key_size)
 184 {
 185         unsigned char zero = 0x0;
 186         __u8 i[4] = {0, 0, 0, 1};
 187         __u8 L[4] = {0, 0, 0, 128};
 188         int rc = 0;
 189         unsigned char prfhash[SMB2_HMACSHA256_SIZE];
 190         unsigned char *hashptr = prfhash;
 191
 192         memset(prfhash, 0x0, SMB2_HMACSHA256_SIZE);
 193         memset(key, 0x0, key_size);
 194
 195         rc = smb3_crypto_shash_allocate(ses->server);
 196         if (rc) {
 197                 cifs_dbg(VFS, "%s: crypto alloc failed\n", __func__);
 198                 goto smb3signkey_ret;
 199         }
 200
 201         rc = crypto_shash_setkey(ses->server->secmech.hmacsha256,
 202                 ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
 203         if (rc) {
 204                 cifs_dbg(VFS, "%s: Could not set with session key\n", __func__);
 205                 goto smb3signkey_ret;
 206         }
 207
 208         rc = crypto_shash_init(&ses->server->secmech.sdeschmacsha256->shash);
 209         if (rc) {
 210                 cifs_dbg(VFS, "%s: Could not init sign hmac\n", __func__);
 211                 goto smb3signkey_ret;
 212         }
 213
 214         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 215                                 i, 4);
 216         if (rc) {
 217                 cifs_dbg(VFS, "%s: Could not update with n\n", __func__);
 218                 goto smb3signkey_ret;
 219         }
 220
 221         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 222                                 label.iov_base, label.iov_len);
 223         if (rc) {
 224                 cifs_dbg(VFS, "%s: Could not update with label\n", __func__);
 225                 goto smb3signkey_ret;
 226         }
 227
 228         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 229                                 &zero, 1);
 230         if (rc) {
 231                 cifs_dbg(VFS, "%s: Could not update with zero\n", __func__);
 232                 goto smb3signkey_ret;
 233         }
 234
 235         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 236                                 context.iov_base, context.iov_len);
 237         if (rc) {
 238                 cifs_dbg(VFS, "%s: Could not update with context\n", __func__);
 239                 goto smb3signkey_ret;
 240         }
 241
 242         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 243                                 L, 4);
 244         if (rc) {
 245                 cifs_dbg(VFS, "%s: Could not update with L\n", __func__);
 246                 goto smb3signkey_ret;
 247         }
 248
 249         rc = crypto_shash_final(&ses->server->secmech.sdeschmacsha256->shash,
 250                                 hashptr);
 251         if (rc) {
 252                 cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
 253                 goto smb3signkey_ret;
 254         }
 255
 256         memcpy(key, hashptr, key_size);
 257
 258 smb3signkey_ret:
 259         return rc;
 260 }
 261
 262 struct derivation {
 263         struct kvec label;
 264         struct kvec context;
 265 };
 266
 267 struct derivation_triplet {
 268         struct derivation signing;
 269         struct derivation encryption;
 270         struct derivation decryption;
 271 };
 272
 273 static int
 274 generate_smb3signingkey(struct cifs_ses *ses,
 275                         const struct derivation_triplet *ptriplet)
 276 {
 277         int rc;
 278
 279         rc = generate_key(ses, ptriplet->signing.label,
 280                           ptriplet->signing.context, ses->smb3signingkey,
 281                           SMB3_SIGN_KEY_SIZE);
 282         if (rc)
 283                 return rc;
 284
 285         rc = generate_key(ses, ptriplet->encryption.label,
 286                           ptriplet->encryption.context, ses->smb3encryptionkey,
 287                           SMB3_SIGN_KEY_SIZE);
 288         if (rc)
 289                 return rc;
 290
 291         return generate_key(ses, ptriplet->decryption.label,
 292                             ptriplet->decryption.context,
 293                             ses->smb3decryptionkey, SMB3_SIGN_KEY_SIZE);
 294 }
 295
 296 int
 297 generate_smb30signingkey(struct cifs_ses *ses)
 298
 299 {
 300         struct derivation_triplet triplet;
 301         struct derivation *d;
 302
 303         d = &triplet.signing;
 304         d->label.iov_base = "SMB2AESCMAC";
 305         d->label.iov_len = 12;
 306         d->context.iov_base = "SmbSign";
 307         d->context.iov_len = 8;
 308
 309         d = &triplet.encryption;
 310         d->label.iov_base = "SMB2AESCCM";
 311         d->label.iov_len = 11;
 312         d->context.iov_base = "ServerIn ";
 313         d->context.iov_len = 10;
 314
 315         d = &triplet.decryption;
 316         d->label.iov_base = "SMB2AESCCM";
 317         d->label.iov_len = 11;
 318         d->context.iov_base = "ServerOut";
 319         d->context.iov_len = 10;
 320
 321         return generate_smb3signingkey(ses, &triplet);
 322 }
 323
 324 int
 325 generate_smb311signingkey(struct cifs_ses *ses)
 326
 327 {
 328         struct derivation_triplet triplet;
 329         struct derivation *d;
 330
 331         d = &triplet.signing;
 332         d->label.iov_base = "SMB2AESCMAC";
 333         d->label.iov_len = 12;
 334         d->context.iov_base = "SmbSign";
 335         d->context.iov_len = 8;
 336
 337         d = &triplet.encryption;
 338         d->label.iov_base = "SMB2AESCCM";
 339         d->label.iov_len = 11;
 340         d->context.iov_base = "ServerIn ";
 341         d->context.iov_len = 10;
 342
 343         d = &triplet.decryption;
 344         d->label.iov_base = "SMB2AESCCM";
 345         d->label.iov_len = 11;
 346         d->context.iov_base = "ServerOut";
 347         d->context.iov_len = 10;
 348
 349         return generate_smb3signingkey(ses, &triplet);
 350 }
 351
 352 int
 353 smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 354 {
 355         int rc = 0;
 356         unsigned char smb3_signature[SMB2_CMACAES_SIZE];
 357         unsigned char *sigptr = smb3_signature;
 358         struct kvec *iov = rqst->rq_iov;
 359         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
 360         struct cifs_ses *ses;
 361
 362         ses = smb2_find_smb_ses(smb2_pdu, server);
 363         if (!ses) {
 364                 cifs_dbg(VFS, "%s: Could not find session\n", __func__);
 365                 return 0;
 366         }
 367
 368         memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE);
 369         memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
 370
 371         rc = crypto_shash_setkey(server->secmech.cmacaes,
 372                 ses->smb3signingkey, SMB2_CMACAES_SIZE);
 373
 374         if (rc) {
 375                 cifs_dbg(VFS, "%s: Could not set key for cmac aes\n", __func__);
 376                 return rc;
 377         }
 378
 379         /*
 380          * we already allocate sdesccmacaes when we init smb3 signing key,
 381          * so unlike smb2 case we do not have to check here if secmech are
 382          * initialized
 383          */
 384         rc = crypto_shash_init(&server->secmech.sdesccmacaes->shash);
 385         if (rc) {
 386                 cifs_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
 387                 return rc;
 388         }
 389
 390         rc = __cifs_calc_signature(rqst, server, sigptr,
 391                                    &server->secmech.sdesccmacaes->shash);
 392
 393         if (!rc)
 394                 memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 395
 396         return rc;
 397 }
 398
 399 /* must be called with server->srv_mutex held */
 400 static int
 401 smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 402 {
 403         int rc = 0;
 404         struct smb2_hdr *smb2_pdu = rqst->rq_iov[0].iov_base;
 405
 406         if (!(smb2_pdu->Flags & SMB2_FLAGS_SIGNED) ||
 407             server->tcpStatus == CifsNeedNegotiate)
 408                 return rc;
 409
 410         if (!server->session_estab) {
 411                 strncpy(smb2_pdu->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_hdr *smb2_pdu = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 426
 427         if ((smb2_pdu->Command == SMB2_NEGOTIATE) ||
 428             (smb2_pdu->Command == SMB2_SESSION_SETUP) ||
 429             (smb2_pdu->Command == SMB2_OPLOCK_BREAK) ||
 430             (!server->session_estab))
 431                 return 0;
 432
 433         /*
 434          * BB what if signatures are supposed to be on for session but
 435          * server does not send one? BB
 436          */
 437
 438         /* Do not need to verify session setups with signature "BSRSPYL " */
 439         if (memcmp(smb2_pdu->Signature, "BSRSPYL ", 8) == 0)
 440                 cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
 441                          smb2_pdu->Command);
 442
 443         /*
 444          * Save off the origiginal signature so we can modify the smb and check
 445          * our calculated signature against what the server sent.
 446          */
 447         memcpy(server_response_sig, smb2_pdu->Signature, SMB2_SIGNATURE_SIZE);
 448
 449         memset(smb2_pdu->Signature, 0, SMB2_SIGNATURE_SIZE);
 450
 451         mutex_lock(&server->srv_mutex);
 452         rc = server->ops->calc_signature(rqst, server);
 453         mutex_unlock(&server->srv_mutex);
 454
 455         if (rc)
 456                 return rc;
 457
 458         if (memcmp(server_response_sig, smb2_pdu->Signature,
 459                    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, struct smb2_hdr *hdr)
 471 {
 472         unsigned int i, num = le16_to_cpu(hdr->CreditCharge);
 473
 474         hdr->MessageId = get_next_mid64(server);
 475         /* skip message numbers according to CreditCharge field */
 476         for (i = 1; i < num; i++)
 477                 get_next_mid(server);
 478 }
 479
 480 static struct mid_q_entry *
 481 smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
 482                      struct TCP_Server_Info *server)
 483 {
 484         struct mid_q_entry *temp;
 485
 486         if (server == NULL) {
 487                 cifs_dbg(VFS, "Null TCP session in smb2_mid_entry_alloc\n");
 488                 return NULL;
 489         }
 490
 491         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
 492         if (temp == NULL)
 493                 return temp;
 494         else {
 495                 memset(temp, 0, sizeof(struct mid_q_entry));
 496                 temp->mid = le64_to_cpu(smb_buffer->MessageId);
 497                 temp->pid = current->pid;
 498                 temp->command = smb_buffer->Command;    /* Always LE */
 499                 temp->when_alloc = jiffies;
 500                 temp->server = server;
 501
 502                 /*
 503                  * The default is for the mid to be synchronous, so the
 504                  * default callback just wakes up the current task.
 505                  */
 506                 temp->callback = cifs_wake_up_task;
 507                 temp->callback_data = current;
 508         }
 509
 510         atomic_inc(&midCount);
 511         temp->mid_state = MID_REQUEST_ALLOCATED;
 512         return temp;
 513 }
 514
 515 static int
 516 smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
 517                    struct mid_q_entry **mid)
 518 {
 519         if (ses->server->tcpStatus == CifsExiting)
 520                 return -ENOENT;
 521
 522         if (ses->server->tcpStatus == CifsNeedReconnect) {
 523                 cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
 524                 return -EAGAIN;
 525         }
 526
 527         if (ses->status == CifsNew) {
 528                 if ((buf->Command != SMB2_SESSION_SETUP) &&
 529                     (buf->Command != SMB2_NEGOTIATE))
 530                         return -EAGAIN;
 531                 /* else ok - we are setting up session */
 532         }
 533
 534         if (ses->status == CifsExiting) {
 535                 if (buf->Command != SMB2_LOGOFF)
 536                         return -EAGAIN;
 537                 /* else ok - we are shutting down the session */
 538         }
 539
 540         *mid = smb2_mid_entry_alloc(buf, ses->server);
 541         if (*mid == NULL)
 542                 return -ENOMEM;
 543         spin_lock(&GlobalMid_Lock);
 544         list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
 545         spin_unlock(&GlobalMid_Lock);
 546         return 0;
 547 }
 548
 549 int
 550 smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 551                    bool log_error)
 552 {
 553         unsigned int len = get_rfc1002_length(mid->resp_buf);
 554         struct kvec iov;
 555         struct smb_rqst rqst = { .rq_iov = &iov,
 556                                  .rq_nvec = 1 };
 557
 558         iov.iov_base = (char *)mid->resp_buf;
 559         iov.iov_len = get_rfc1002_length(mid->resp_buf) + 4;
 560
 561         dump_smb(mid->resp_buf, min_t(u32, 80, len));
 562         /* convert the length into a more usable form */
 563         if (len > 24 && server->sign) {
 564                 int rc;
 565
 566                 rc = smb2_verify_signature(&rqst, server);
 567                 if (rc)
 568                         cifs_dbg(VFS, "SMB signature verification returned error = %d\n",
 569                                  rc);
 570         }
 571
 572         return map_smb2_to_linux_error(mid->resp_buf, log_error);
 573 }
 574
 575 struct mid_q_entry *
 576 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
 577 {
 578         int rc;
 579         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 580         struct mid_q_entry *mid;
 581
 582         smb2_seq_num_into_buf(ses->server, hdr);
 583
 584         rc = smb2_get_mid_entry(ses, hdr, &mid);
 585         if (rc)
 586                 return ERR_PTR(rc);
 587         rc = smb2_sign_rqst(rqst, ses->server);
 588         if (rc) {
 589                 cifs_delete_mid(mid);
 590                 return ERR_PTR(rc);
 591         }
 592         return mid;
 593 }
 594
 595 struct mid_q_entry *
 596 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 597 {
 598         int rc;
 599         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 600         struct mid_q_entry *mid;
 601
 602         smb2_seq_num_into_buf(server, hdr);
 603
 604         mid = smb2_mid_entry_alloc(hdr, server);
 605         if (mid == NULL)
 606                 return ERR_PTR(-ENOMEM);
 607
 608         rc = smb2_sign_rqst(rqst, server);
 609         if (rc) {
 610                 DeleteMidQEntry(mid);
 611                 return ERR_PTR(rc);
 612         }
 613
 614         return mid;
 615 }