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 <crypto/aead.h>
  35 #include "smb2pdu.h"
  36 #include "cifsglob.h"
  37 #include "cifsproto.h"
  38 #include "smb2proto.h"
  39 #include "cifs_debug.h"
  40 #include "smb2status.h"
  41 #include "smb2glob.h"
  42
  43 static int
  44 smb2_crypto_shash_allocate(struct TCP_Server_Info *server)
  45 {
  46         int rc;
  47         unsigned int size;
  48
  49         if (server->secmech.sdeschmacsha256 != NULL)
  50                 return 0; /* already allocated */
  51
  52         server->secmech.hmacsha256 = crypto_alloc_shash("hmac(sha256)", 0, 0);
  53         if (IS_ERR(server->secmech.hmacsha256)) {
  54                 cifs_dbg(VFS, "could not allocate crypto hmacsha256\n");
  55                 rc = PTR_ERR(server->secmech.hmacsha256);
  56                 server->secmech.hmacsha256 = NULL;
  57                 return rc;
  58         }
  59
  60         size = sizeof(struct shash_desc) +
  61                         crypto_shash_descsize(server->secmech.hmacsha256);
  62         server->secmech.sdeschmacsha256 = kmalloc(size, GFP_KERNEL);
  63         if (!server->secmech.sdeschmacsha256) {
  64                 crypto_free_shash(server->secmech.hmacsha256);
  65                 server->secmech.hmacsha256 = NULL;
  66                 return -ENOMEM;
  67         }
  68         server->secmech.sdeschmacsha256->shash.tfm = server->secmech.hmacsha256;
  69         server->secmech.sdeschmacsha256->shash.flags = 0x0;
  70
  71         return 0;
  72 }
  73
  74 static int
  75 smb3_crypto_shash_allocate(struct TCP_Server_Info *server)
  76 {
  77         unsigned int size;
  78         int rc;
  79
  80         if (server->secmech.sdesccmacaes != NULL)
  81                 return 0;  /* already allocated */
  82
  83         rc = smb2_crypto_shash_allocate(server);
  84         if (rc)
  85                 return rc;
  86
  87         server->secmech.cmacaes = crypto_alloc_shash("cmac(aes)", 0, 0);
  88         if (IS_ERR(server->secmech.cmacaes)) {
  89                 cifs_dbg(VFS, "could not allocate crypto cmac-aes");
  90                 kfree(server->secmech.sdeschmacsha256);
  91                 server->secmech.sdeschmacsha256 = NULL;
  92                 crypto_free_shash(server->secmech.hmacsha256);
  93                 server->secmech.hmacsha256 = NULL;
  94                 rc = PTR_ERR(server->secmech.cmacaes);
  95                 server->secmech.cmacaes = NULL;
  96                 return rc;
  97         }
  98
  99         size = sizeof(struct shash_desc) +
 100                         crypto_shash_descsize(server->secmech.cmacaes);
 101         server->secmech.sdesccmacaes = kmalloc(size, GFP_KERNEL);
 102         if (!server->secmech.sdesccmacaes) {
 103                 cifs_dbg(VFS, "%s: Can't alloc cmacaes\n", __func__);
 104                 kfree(server->secmech.sdeschmacsha256);
 105                 server->secmech.sdeschmacsha256 = NULL;
 106                 crypto_free_shash(server->secmech.hmacsha256);
 107                 crypto_free_shash(server->secmech.cmacaes);
 108                 server->secmech.hmacsha256 = NULL;
 109                 server->secmech.cmacaes = NULL;
 110                 return -ENOMEM;
 111         }
 112         server->secmech.sdesccmacaes->shash.tfm = server->secmech.cmacaes;
 113         server->secmech.sdesccmacaes->shash.flags = 0x0;
 114
 115         return 0;
 116 }
 117
 118 struct cifs_ses *
 119 smb2_find_smb_ses(struct TCP_Server_Info *server, __u64 ses_id)
 120 {
 121         struct cifs_ses *ses;
 122
 123         spin_lock(&cifs_tcp_ses_lock);
 124         list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
 125                 if (ses->Suid != ses_id)
 126                         continue;
 127                 spin_unlock(&cifs_tcp_ses_lock);
 128                 return ses;
 129         }
 130         spin_unlock(&cifs_tcp_ses_lock);
 131
 132         return NULL;
 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_sync_hdr *shdr = (struct smb2_sync_hdr *)iov[1].iov_base;
 143         struct cifs_ses *ses;
 144
 145         ses = smb2_find_smb_ses(server, shdr->SessionId);
 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(shdr->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(shdr->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_sync_hdr *shdr = (struct smb2_sync_hdr *)iov[1].iov_base;
 360         struct cifs_ses *ses;
 361
 362         ses = smb2_find_smb_ses(server, shdr->SessionId);
 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(shdr->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(shdr->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_sync_hdr *shdr =
 405                         (struct smb2_sync_hdr *)rqst->rq_iov[1].iov_base;
 406
 407         if (!(shdr->Flags & SMB2_FLAGS_SIGNED) ||
 408             server->tcpStatus == CifsNeedNegotiate)
 409                 return rc;
 410
 411         if (!server->session_estab) {
 412                 strncpy(shdr->Signature, "BSRSPYL", 8);
 413                 return rc;
 414         }
 415
 416         rc = server->ops->calc_signature(rqst, server);
 417
 418         return rc;
 419 }
 420
 421 int
 422 smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 423 {
 424         unsigned int rc;
 425         char server_response_sig[16];
 426         struct smb2_sync_hdr *shdr =
 427                         (struct smb2_sync_hdr *)rqst->rq_iov[1].iov_base;
 428
 429         if ((shdr->Command == SMB2_NEGOTIATE) ||
 430             (shdr->Command == SMB2_SESSION_SETUP) ||
 431             (shdr->Command == SMB2_OPLOCK_BREAK) ||
 432             (!server->session_estab))
 433                 return 0;
 434
 435         /*
 436          * BB what if signatures are supposed to be on for session but
 437          * server does not send one? BB
 438          */
 439
 440         /* Do not need to verify session setups with signature "BSRSPYL " */
 441         if (memcmp(shdr->Signature, "BSRSPYL ", 8) == 0)
 442                 cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
 443                          shdr->Command);
 444
 445         /*
 446          * Save off the origiginal signature so we can modify the smb and check
 447          * our calculated signature against what the server sent.
 448          */
 449         memcpy(server_response_sig, shdr->Signature, SMB2_SIGNATURE_SIZE);
 450
 451         memset(shdr->Signature, 0, SMB2_SIGNATURE_SIZE);
 452
 453         mutex_lock(&server->srv_mutex);
 454         rc = server->ops->calc_signature(rqst, server);
 455         mutex_unlock(&server->srv_mutex);
 456
 457         if (rc)
 458                 return rc;
 459
 460         if (memcmp(server_response_sig, shdr->Signature, SMB2_SIGNATURE_SIZE))
 461                 return -EACCES;
 462         else
 463                 return 0;
 464 }
 465
 466 /*
 467  * Set message id for the request. Should be called after wait_for_free_request
 468  * and when srv_mutex is held.
 469  */
 470 static inline void
 471 smb2_seq_num_into_buf(struct TCP_Server_Info *server,
 472                       struct smb2_sync_hdr *shdr)
 473 {
 474         unsigned int i, num = le16_to_cpu(shdr->CreditCharge);
 475
 476         shdr->MessageId = get_next_mid64(server);
 477         /* skip message numbers according to CreditCharge field */
 478         for (i = 1; i < num; i++)
 479                 get_next_mid(server);
 480 }
 481
 482 static struct mid_q_entry *
 483 smb2_mid_entry_alloc(const struct smb2_sync_hdr *shdr,
 484                      struct TCP_Server_Info *server)
 485 {
 486         struct mid_q_entry *temp;
 487
 488         if (server == NULL) {
 489                 cifs_dbg(VFS, "Null TCP session in smb2_mid_entry_alloc\n");
 490                 return NULL;
 491         }
 492
 493         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
 494         if (temp == NULL)
 495                 return temp;
 496         else {
 497                 memset(temp, 0, sizeof(struct mid_q_entry));
 498                 temp->mid = le64_to_cpu(shdr->MessageId);
 499                 temp->pid = current->pid;
 500                 temp->command = shdr->Command; /* Always LE */
 501                 temp->when_alloc = jiffies;
 502                 temp->server = server;
 503
 504                 /*
 505                  * The default is for the mid to be synchronous, so the
 506                  * default callback just wakes up the current task.
 507                  */
 508                 temp->callback = cifs_wake_up_task;
 509                 temp->callback_data = current;
 510         }
 511
 512         atomic_inc(&midCount);
 513         temp->mid_state = MID_REQUEST_ALLOCATED;
 514         return temp;
 515 }
 516
 517 static int
 518 smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_sync_hdr *shdr,
 519                    struct mid_q_entry **mid)
 520 {
 521         if (ses->server->tcpStatus == CifsExiting)
 522                 return -ENOENT;
 523
 524         if (ses->server->tcpStatus == CifsNeedReconnect) {
 525                 cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
 526                 return -EAGAIN;
 527         }
 528
 529         if (ses->status == CifsNew) {
 530                 if ((shdr->Command != SMB2_SESSION_SETUP) &&
 531                     (shdr->Command != SMB2_NEGOTIATE))
 532                         return -EAGAIN;
 533                 /* else ok - we are setting up session */
 534         }
 535
 536         if (ses->status == CifsExiting) {
 537                 if (shdr->Command != SMB2_LOGOFF)
 538                         return -EAGAIN;
 539                 /* else ok - we are shutting down the session */
 540         }
 541
 542         *mid = smb2_mid_entry_alloc(shdr, ses->server);
 543         if (*mid == NULL)
 544                 return -ENOMEM;
 545         spin_lock(&GlobalMid_Lock);
 546         list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
 547         spin_unlock(&GlobalMid_Lock);
 548         return 0;
 549 }
 550
 551 int
 552 smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 553                    bool log_error)
 554 {
 555         unsigned int len = get_rfc1002_length(mid->resp_buf);
 556         struct kvec iov[2];
 557         struct smb_rqst rqst = { .rq_iov = iov,
 558                                  .rq_nvec = 2 };
 559
 560         iov[0].iov_base = (char *)mid->resp_buf;
 561         iov[0].iov_len = 4;
 562         iov[1].iov_base = (char *)mid->resp_buf + 4;
 563         iov[1].iov_len = len;
 564
 565         dump_smb(mid->resp_buf, min_t(u32, 80, len));
 566         /* convert the length into a more usable form */
 567         if (len > 24 && server->sign && !mid->decrypted) {
 568                 int rc;
 569
 570                 rc = smb2_verify_signature(&rqst, server);
 571                 if (rc)
 572                         cifs_dbg(VFS, "SMB signature verification returned error = %d\n",
 573                                  rc);
 574         }
 575
 576         return map_smb2_to_linux_error(mid->resp_buf, log_error);
 577 }
 578
 579 struct mid_q_entry *
 580 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
 581 {
 582         int rc;
 583         struct smb2_sync_hdr *shdr =
 584                         (struct smb2_sync_hdr *)rqst->rq_iov[1].iov_base;
 585         struct mid_q_entry *mid;
 586
 587         smb2_seq_num_into_buf(ses->server, shdr);
 588
 589         rc = smb2_get_mid_entry(ses, shdr, &mid);
 590         if (rc)
 591                 return ERR_PTR(rc);
 592         rc = smb2_sign_rqst(rqst, ses->server);
 593         if (rc) {
 594                 cifs_delete_mid(mid);
 595                 return ERR_PTR(rc);
 596         }
 597         return mid;
 598 }
 599
 600 struct mid_q_entry *
 601 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 602 {
 603         int rc;
 604         struct smb2_sync_hdr *shdr =
 605                         (struct smb2_sync_hdr *)rqst->rq_iov[1].iov_base;
 606         struct mid_q_entry *mid;
 607
 608         smb2_seq_num_into_buf(server, shdr);
 609
 610         mid = smb2_mid_entry_alloc(shdr, server);
 611         if (mid == NULL)
 612                 return ERR_PTR(-ENOMEM);
 613
 614         rc = smb2_sign_rqst(rqst, server);
 615         if (rc) {
 616                 DeleteMidQEntry(mid);
 617                 return ERR_PTR(rc);
 618         }
 619
 620         return mid;
 621 }
 622
 623 int
 624 smb3_crypto_aead_allocate(struct TCP_Server_Info *server)
 625 {
 626         struct crypto_aead *tfm;
 627
 628         if (!server->secmech.ccmaesencrypt) {
 629                 tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
 630                 if (IS_ERR(tfm)) {
 631                         cifs_dbg(VFS, "%s: Failed to alloc encrypt aead\n",
 632                                  __func__);
 633                         return PTR_ERR(tfm);
 634                 }
 635                 server->secmech.ccmaesencrypt = tfm;
 636         }
 637
 638         if (!server->secmech.ccmaesdecrypt) {
 639                 tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
 640                 if (IS_ERR(tfm)) {
 641                         crypto_free_aead(server->secmech.ccmaesencrypt);
 642                         server->secmech.ccmaesencrypt = NULL;
 643                         cifs_dbg(VFS, "%s: Failed to alloc decrypt aead\n",
 644                                  __func__);
 645                         return PTR_ERR(tfm);
 646                 }
 647                 server->secmech.ccmaesdecrypt = tfm;
 648         }
 649
 650         return 0;
 651 }