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_unlocked(struct TCP_Server_Info *server, __u64 ses_id)
 119 {
 120         struct cifs_ses *ses;
 121
 122         list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
 123                 if (ses->Suid != ses_id)
 124                         continue;
 125                 return ses;
 126         }
 127
 128         return NULL;
 129 }
 130
 131 struct cifs_ses *
 132 smb2_find_smb_ses(struct TCP_Server_Info *server, __u64 ses_id)
 133 {
 134         struct cifs_ses *ses;
 135
 136         spin_lock(&cifs_tcp_ses_lock);
 137         ses = smb2_find_smb_ses_unlocked(server, ses_id);
 138         spin_unlock(&cifs_tcp_ses_lock);
 139
 140         return ses;
 141 }
 142
 143 static struct cifs_tcon *
 144 smb2_find_smb_sess_tcon_unlocked(struct cifs_ses *ses, __u32  tid)
 145 {
 146         struct cifs_tcon *tcon;
 147
 148         list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
 149                 if (tcon->tid != tid)
 150                         continue;
 151                 ++tcon->tc_count;
 152                 return tcon;
 153         }
 154
 155         return NULL;
 156 }
 157
 158 /*
 159  * Obtain tcon corresponding to the tid in the given
 160  * cifs_ses
 161  */
 162
 163 struct cifs_tcon *
 164 smb2_find_smb_tcon(struct TCP_Server_Info *server, __u64 ses_id, __u32 tid)
 165 {
 166         struct cifs_ses *ses;
 167         struct cifs_tcon *tcon;
 168
 169         spin_lock(&cifs_tcp_ses_lock);
 170         ses = smb2_find_smb_ses_unlocked(server, ses_id);
 171         if (!ses) {
 172                 spin_unlock(&cifs_tcp_ses_lock);
 173                 return NULL;
 174         }
 175         tcon = smb2_find_smb_sess_tcon_unlocked(ses, tid);
 176         spin_unlock(&cifs_tcp_ses_lock);
 177
 178         return tcon;
 179 }
 180
 181 int
 182 smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 183 {
 184         int rc;
 185         unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
 186         unsigned char *sigptr = smb2_signature;
 187         struct kvec *iov = rqst->rq_iov;
 188         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
 189         struct cifs_ses *ses;
 190
 191         ses = smb2_find_smb_ses(server, smb2_pdu->SessionId);
 192         if (!ses) {
 193                 cifs_dbg(VFS, "%s: Could not find session\n", __func__);
 194                 return 0;
 195         }
 196
 197         memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
 198         memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
 199
 200         rc = smb2_crypto_shash_allocate(server);
 201         if (rc) {
 202                 cifs_dbg(VFS, "%s: shah256 alloc failed\n", __func__);
 203                 return rc;
 204         }
 205
 206         rc = crypto_shash_setkey(server->secmech.hmacsha256,
 207                 ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
 208         if (rc) {
 209                 cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
 210                 return rc;
 211         }
 212
 213         rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
 214         if (rc) {
 215                 cifs_dbg(VFS, "%s: Could not init sha256", __func__);
 216                 return rc;
 217         }
 218
 219         rc = __cifs_calc_signature(rqst, server, sigptr,
 220                 &server->secmech.sdeschmacsha256->shash);
 221
 222         if (!rc)
 223                 memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 224
 225         return rc;
 226 }
 227
 228 static int generate_key(struct cifs_ses *ses, struct kvec label,
 229                         struct kvec context, __u8 *key, unsigned int key_size)
 230 {
 231         unsigned char zero = 0x0;
 232         __u8 i[4] = {0, 0, 0, 1};
 233         __u8 L[4] = {0, 0, 0, 128};
 234         int rc = 0;
 235         unsigned char prfhash[SMB2_HMACSHA256_SIZE];
 236         unsigned char *hashptr = prfhash;
 237
 238         memset(prfhash, 0x0, SMB2_HMACSHA256_SIZE);
 239         memset(key, 0x0, key_size);
 240
 241         rc = smb3_crypto_shash_allocate(ses->server);
 242         if (rc) {
 243                 cifs_dbg(VFS, "%s: crypto alloc failed\n", __func__);
 244                 goto smb3signkey_ret;
 245         }
 246
 247         rc = crypto_shash_setkey(ses->server->secmech.hmacsha256,
 248                 ses->auth_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
 249         if (rc) {
 250                 cifs_dbg(VFS, "%s: Could not set with session key\n", __func__);
 251                 goto smb3signkey_ret;
 252         }
 253
 254         rc = crypto_shash_init(&ses->server->secmech.sdeschmacsha256->shash);
 255         if (rc) {
 256                 cifs_dbg(VFS, "%s: Could not init sign hmac\n", __func__);
 257                 goto smb3signkey_ret;
 258         }
 259
 260         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 261                                 i, 4);
 262         if (rc) {
 263                 cifs_dbg(VFS, "%s: Could not update with n\n", __func__);
 264                 goto smb3signkey_ret;
 265         }
 266
 267         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 268                                 label.iov_base, label.iov_len);
 269         if (rc) {
 270                 cifs_dbg(VFS, "%s: Could not update with label\n", __func__);
 271                 goto smb3signkey_ret;
 272         }
 273
 274         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 275                                 &zero, 1);
 276         if (rc) {
 277                 cifs_dbg(VFS, "%s: Could not update with zero\n", __func__);
 278                 goto smb3signkey_ret;
 279         }
 280
 281         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 282                                 context.iov_base, context.iov_len);
 283         if (rc) {
 284                 cifs_dbg(VFS, "%s: Could not update with context\n", __func__);
 285                 goto smb3signkey_ret;
 286         }
 287
 288         rc = crypto_shash_update(&ses->server->secmech.sdeschmacsha256->shash,
 289                                 L, 4);
 290         if (rc) {
 291                 cifs_dbg(VFS, "%s: Could not update with L\n", __func__);
 292                 goto smb3signkey_ret;
 293         }
 294
 295         rc = crypto_shash_final(&ses->server->secmech.sdeschmacsha256->shash,
 296                                 hashptr);
 297         if (rc) {
 298                 cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
 299                 goto smb3signkey_ret;
 300         }
 301
 302         memcpy(key, hashptr, key_size);
 303
 304 smb3signkey_ret:
 305         return rc;
 306 }
 307
 308 struct derivation {
 309         struct kvec label;
 310         struct kvec context;
 311 };
 312
 313 struct derivation_triplet {
 314         struct derivation signing;
 315         struct derivation encryption;
 316         struct derivation decryption;
 317 };
 318
 319 static int
 320 generate_smb3signingkey(struct cifs_ses *ses,
 321                         const struct derivation_triplet *ptriplet)
 322 {
 323         int rc;
 324
 325         rc = generate_key(ses, ptriplet->signing.label,
 326                           ptriplet->signing.context, ses->smb3signingkey,
 327                           SMB3_SIGN_KEY_SIZE);
 328         if (rc)
 329                 return rc;
 330
 331         rc = generate_key(ses, ptriplet->encryption.label,
 332                           ptriplet->encryption.context, ses->smb3encryptionkey,
 333                           SMB3_SIGN_KEY_SIZE);
 334         if (rc)
 335                 return rc;
 336
 337         return generate_key(ses, ptriplet->decryption.label,
 338                             ptriplet->decryption.context,
 339                             ses->smb3decryptionkey, SMB3_SIGN_KEY_SIZE);
 340 }
 341
 342 int
 343 generate_smb30signingkey(struct cifs_ses *ses)
 344
 345 {
 346         struct derivation_triplet triplet;
 347         struct derivation *d;
 348
 349         d = &triplet.signing;
 350         d->label.iov_base = "SMB2AESCMAC";
 351         d->label.iov_len = 12;
 352         d->context.iov_base = "SmbSign";
 353         d->context.iov_len = 8;
 354
 355         d = &triplet.encryption;
 356         d->label.iov_base = "SMB2AESCCM";
 357         d->label.iov_len = 11;
 358         d->context.iov_base = "ServerIn ";
 359         d->context.iov_len = 10;
 360
 361         d = &triplet.decryption;
 362         d->label.iov_base = "SMB2AESCCM";
 363         d->label.iov_len = 11;
 364         d->context.iov_base = "ServerOut";
 365         d->context.iov_len = 10;
 366
 367         return generate_smb3signingkey(ses, &triplet);
 368 }
 369
 370 int
 371 generate_smb311signingkey(struct cifs_ses *ses)
 372
 373 {
 374         struct derivation_triplet triplet;
 375         struct derivation *d;
 376
 377         d = &triplet.signing;
 378         d->label.iov_base = "SMB2AESCMAC";
 379         d->label.iov_len = 12;
 380         d->context.iov_base = "SmbSign";
 381         d->context.iov_len = 8;
 382
 383         d = &triplet.encryption;
 384         d->label.iov_base = "SMB2AESCCM";
 385         d->label.iov_len = 11;
 386         d->context.iov_base = "ServerIn ";
 387         d->context.iov_len = 10;
 388
 389         d = &triplet.decryption;
 390         d->label.iov_base = "SMB2AESCCM";
 391         d->label.iov_len = 11;
 392         d->context.iov_base = "ServerOut";
 393         d->context.iov_len = 10;
 394
 395         return generate_smb3signingkey(ses, &triplet);
 396 }
 397
 398 int
 399 smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 400 {
 401         int rc = 0;
 402         unsigned char smb3_signature[SMB2_CMACAES_SIZE];
 403         unsigned char *sigptr = smb3_signature;
 404         struct kvec *iov = rqst->rq_iov;
 405         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
 406         struct cifs_ses *ses;
 407
 408         ses = smb2_find_smb_ses(server, smb2_pdu->SessionId);
 409         if (!ses) {
 410                 cifs_dbg(VFS, "%s: Could not find session\n", __func__);
 411                 return 0;
 412         }
 413
 414         memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE);
 415         memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
 416
 417         rc = crypto_shash_setkey(server->secmech.cmacaes,
 418                 ses->smb3signingkey, SMB2_CMACAES_SIZE);
 419
 420         if (rc) {
 421                 cifs_dbg(VFS, "%s: Could not set key for cmac aes\n", __func__);
 422                 return rc;
 423         }
 424
 425         /*
 426          * we already allocate sdesccmacaes when we init smb3 signing key,
 427          * so unlike smb2 case we do not have to check here if secmech are
 428          * initialized
 429          */
 430         rc = crypto_shash_init(&server->secmech.sdesccmacaes->shash);
 431         if (rc) {
 432                 cifs_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
 433                 return rc;
 434         }
 435
 436         rc = __cifs_calc_signature(rqst, server, sigptr,
 437                                    &server->secmech.sdesccmacaes->shash);
 438
 439         if (!rc)
 440                 memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 441
 442         return rc;
 443 }
 444
 445 /* must be called with server->srv_mutex held */
 446 static int
 447 smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 448 {
 449         int rc = 0;
 450         struct smb2_hdr *smb2_pdu = rqst->rq_iov[0].iov_base;
 451
 452         if (!(smb2_pdu->Flags & SMB2_FLAGS_SIGNED) ||
 453             server->tcpStatus == CifsNeedNegotiate)
 454                 return rc;
 455
 456         if (!server->session_estab) {
 457                 strncpy(smb2_pdu->Signature, "BSRSPYL", 8);
 458                 return rc;
 459         }
 460
 461         rc = server->ops->calc_signature(rqst, server);
 462
 463         return rc;
 464 }
 465
 466 int
 467 smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 468 {
 469         unsigned int rc;
 470         char server_response_sig[16];
 471         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 472
 473         if ((smb2_pdu->Command == SMB2_NEGOTIATE) ||
 474             (smb2_pdu->Command == SMB2_SESSION_SETUP) ||
 475             (smb2_pdu->Command == SMB2_OPLOCK_BREAK) ||
 476             (!server->session_estab))
 477                 return 0;
 478
 479         /*
 480          * BB what if signatures are supposed to be on for session but
 481          * server does not send one? BB
 482          */
 483
 484         /* Do not need to verify session setups with signature "BSRSPYL " */
 485         if (memcmp(smb2_pdu->Signature, "BSRSPYL ", 8) == 0)
 486                 cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
 487                          smb2_pdu->Command);
 488
 489         /*
 490          * Save off the origiginal signature so we can modify the smb and check
 491          * our calculated signature against what the server sent.
 492          */
 493         memcpy(server_response_sig, smb2_pdu->Signature, SMB2_SIGNATURE_SIZE);
 494
 495         memset(smb2_pdu->Signature, 0, SMB2_SIGNATURE_SIZE);
 496
 497         mutex_lock(&server->srv_mutex);
 498         rc = server->ops->calc_signature(rqst, server);
 499         mutex_unlock(&server->srv_mutex);
 500
 501         if (rc)
 502                 return rc;
 503
 504         if (memcmp(server_response_sig, smb2_pdu->Signature,
 505                    SMB2_SIGNATURE_SIZE))
 506                 return -EACCES;
 507         else
 508                 return 0;
 509 }
 510
 511 /*
 512  * Set message id for the request. Should be called after wait_for_free_request
 513  * and when srv_mutex is held.
 514  */
 515 static inline void
 516 smb2_seq_num_into_buf(struct TCP_Server_Info *server, struct smb2_hdr *hdr)
 517 {
 518         unsigned int i, num = le16_to_cpu(hdr->CreditCharge);
 519
 520         hdr->MessageId = get_next_mid64(server);
 521         /* skip message numbers according to CreditCharge field */
 522         for (i = 1; i < num; i++)
 523                 get_next_mid(server);
 524 }
 525
 526 static struct mid_q_entry *
 527 smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
 528                      struct TCP_Server_Info *server)
 529 {
 530         struct mid_q_entry *temp;
 531
 532         if (server == NULL) {
 533                 cifs_dbg(VFS, "Null TCP session in smb2_mid_entry_alloc\n");
 534                 return NULL;
 535         }
 536
 537         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
 538         if (temp == NULL)
 539                 return temp;
 540         else {
 541                 memset(temp, 0, sizeof(struct mid_q_entry));
 542                 temp->mid = le64_to_cpu(smb_buffer->MessageId);
 543                 temp->pid = current->pid;
 544                 temp->command = smb_buffer->Command;    /* Always LE */
 545                 temp->when_alloc = jiffies;
 546                 temp->server = server;
 547
 548                 /*
 549                  * The default is for the mid to be synchronous, so the
 550                  * default callback just wakes up the current task.
 551                  */
 552                 temp->callback = cifs_wake_up_task;
 553                 temp->callback_data = current;
 554         }
 555
 556         atomic_inc(&midCount);
 557         temp->mid_state = MID_REQUEST_ALLOCATED;
 558         return temp;
 559 }
 560
 561 static int
 562 smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
 563                    struct mid_q_entry **mid)
 564 {
 565         if (ses->server->tcpStatus == CifsExiting)
 566                 return -ENOENT;
 567
 568         if (ses->server->tcpStatus == CifsNeedReconnect) {
 569                 cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
 570                 return -EAGAIN;
 571         }
 572
 573         if (ses->status == CifsNew) {
 574                 if ((buf->Command != SMB2_SESSION_SETUP) &&
 575                     (buf->Command != SMB2_NEGOTIATE))
 576                         return -EAGAIN;
 577                 /* else ok - we are setting up session */
 578         }
 579
 580         if (ses->status == CifsExiting) {
 581                 if (buf->Command != SMB2_LOGOFF)
 582                         return -EAGAIN;
 583                 /* else ok - we are shutting down the session */
 584         }
 585
 586         *mid = smb2_mid_entry_alloc(buf, ses->server);
 587         if (*mid == NULL)
 588                 return -ENOMEM;
 589         spin_lock(&GlobalMid_Lock);
 590         list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
 591         spin_unlock(&GlobalMid_Lock);
 592         return 0;
 593 }
 594
 595 int
 596 smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 597                    bool log_error)
 598 {
 599         unsigned int len = get_rfc1002_length(mid->resp_buf);
 600         struct kvec iov;
 601         struct smb_rqst rqst = { .rq_iov = &iov,
 602                                  .rq_nvec = 1 };
 603
 604         iov.iov_base = (char *)mid->resp_buf;
 605         iov.iov_len = get_rfc1002_length(mid->resp_buf) + 4;
 606
 607         dump_smb(mid->resp_buf, min_t(u32, 80, len));
 608         /* convert the length into a more usable form */
 609         if (len > 24 && server->sign) {
 610                 int rc;
 611
 612                 rc = smb2_verify_signature(&rqst, server);
 613                 if (rc)
 614                         cifs_dbg(VFS, "SMB signature verification returned error = %d\n",
 615                                  rc);
 616         }
 617
 618         return map_smb2_to_linux_error(mid->resp_buf, log_error);
 619 }
 620
 621 struct mid_q_entry *
 622 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
 623 {
 624         int rc;
 625         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 626         struct mid_q_entry *mid;
 627
 628         smb2_seq_num_into_buf(ses->server, hdr);
 629
 630         rc = smb2_get_mid_entry(ses, hdr, &mid);
 631         if (rc)
 632                 return ERR_PTR(rc);
 633         rc = smb2_sign_rqst(rqst, ses->server);
 634         if (rc) {
 635                 cifs_delete_mid(mid);
 636                 return ERR_PTR(rc);
 637         }
 638         return mid;
 639 }
 640
 641 struct mid_q_entry *
 642 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 643 {
 644         int rc;
 645         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 646         struct mid_q_entry *mid;
 647
 648         smb2_seq_num_into_buf(server, hdr);
 649
 650         mid = smb2_mid_entry_alloc(hdr, server);
 651         if (mid == NULL)
 652                 return ERR_PTR(-ENOMEM);
 653
 654         rc = smb2_sign_rqst(rqst, server);
 655         if (rc) {
 656                 DeleteMidQEntry(mid);
 657                 return ERR_PTR(rc);
 658         }
 659
 660         return mid;
 661 }