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 int
  43 smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
  44 {
  45         int i, rc;
  46         unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
  47         unsigned char *sigptr = smb2_signature;
  48         struct kvec *iov = rqst->rq_iov;
  49         int n_vec = rqst->rq_nvec;
  50         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
  51
  52         memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
  53         memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
  54
  55         rc = crypto_shash_setkey(server->secmech.hmacsha256,
  56                 server->session_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
  57         if (rc) {
  58                 cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
  59                 return rc;
  60         }
  61
  62         rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
  63         if (rc) {
  64                 cifs_dbg(VFS, "%s: Could not init md5\n", __func__);
  65                 return rc;
  66         }
  67
  68         for (i = 0; i < n_vec; i++) {
  69                 if (iov[i].iov_len == 0)
  70                         continue;
  71                 if (iov[i].iov_base == NULL) {
  72                         cifs_dbg(VFS, "null iovec entry\n");
  73                         return -EIO;
  74                 }
  75                 /*
  76                  * The first entry includes a length field (which does not get
  77                  * signed that occupies the first 4 bytes before the header).
  78                  */
  79                 if (i == 0) {
  80                         if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
  81                                 break; /* nothing to sign or corrupt header */
  82                         rc =
  83                         crypto_shash_update(
  84                                 &server->secmech.sdeschmacsha256->shash,
  85                                 iov[i].iov_base + 4, iov[i].iov_len - 4);
  86                 } else {
  87                         rc =
  88                         crypto_shash_update(
  89                                 &server->secmech.sdeschmacsha256->shash,
  90                                 iov[i].iov_base, iov[i].iov_len);
  91                 }
  92                 if (rc) {
  93                         cifs_dbg(VFS, "%s: Could not update with payload\n",
  94                                  __func__);
  95                         return rc;
  96                 }
  97         }
  98
  99         /* now hash over the rq_pages array */
 100         for (i = 0; i < rqst->rq_npages; i++) {
 101                 struct kvec p_iov;
 102
 103                 cifs_rqst_page_to_kvec(rqst, i, &p_iov);
 104                 crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
 105                                         p_iov.iov_base, p_iov.iov_len);
 106                 kunmap(rqst->rq_pages[i]);
 107         }
 108
 109         rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
 110                                 sigptr);
 111         if (rc)
 112                 cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
 113
 114         memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 115
 116         return rc;
 117 }
 118
 119 void
 120 generate_smb3signingkey(struct TCP_Server_Info *server)
 121 {
 122         unsigned char zero = 0x0;
 123         __u8 i[4] = {0, 0, 0, 1};
 124         __u8 L[4] = {0, 0, 0, 128};
 125         int rc = 0;
 126         unsigned char prfhash[SMB2_HMACSHA256_SIZE];
 127         unsigned char *hashptr = prfhash;
 128
 129         memset(prfhash, 0x0, SMB2_HMACSHA256_SIZE);
 130         memset(server->smb3signingkey, 0x0, SMB3_SIGNKEY_SIZE);
 131
 132         rc = crypto_shash_setkey(server->secmech.hmacsha256,
 133                 server->session_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
 134         if (rc) {
 135                 cifs_dbg(VFS, "%s: Could not set with session key\n", __func__);
 136                 goto smb3signkey_ret;
 137         }
 138
 139         rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
 140         if (rc) {
 141                 cifs_dbg(VFS, "%s: Could not init sign hmac\n", __func__);
 142                 goto smb3signkey_ret;
 143         }
 144
 145         rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
 146                                 i, 4);
 147         if (rc) {
 148                 cifs_dbg(VFS, "%s: Could not update with n\n", __func__);
 149                 goto smb3signkey_ret;
 150         }
 151
 152         rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
 153                                 "SMB2AESCMAC", 12);
 154         if (rc) {
 155                 cifs_dbg(VFS, "%s: Could not update with label\n", __func__);
 156                 goto smb3signkey_ret;
 157         }
 158
 159         rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
 160                                 &zero, 1);
 161         if (rc) {
 162                 cifs_dbg(VFS, "%s: Could not update with zero\n", __func__);
 163                 goto smb3signkey_ret;
 164         }
 165
 166         rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
 167                                 "SmbSign", 8);
 168         if (rc) {
 169                 cifs_dbg(VFS, "%s: Could not update with context\n", __func__);
 170                 goto smb3signkey_ret;
 171         }
 172
 173         rc = crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
 174                                 L, 4);
 175         if (rc) {
 176                 cifs_dbg(VFS, "%s: Could not update with L\n", __func__);
 177                 goto smb3signkey_ret;
 178         }
 179
 180         rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
 181                                 hashptr);
 182         if (rc) {
 183                 cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
 184                 goto smb3signkey_ret;
 185         }
 186
 187         memcpy(server->smb3signingkey, hashptr, SMB3_SIGNKEY_SIZE);
 188
 189 smb3signkey_ret:
 190         return;
 191 }
 192
 193 int
 194 smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 195 {
 196         int i, rc;
 197         unsigned char smb3_signature[SMB2_CMACAES_SIZE];
 198         unsigned char *sigptr = smb3_signature;
 199         struct kvec *iov = rqst->rq_iov;
 200         int n_vec = rqst->rq_nvec;
 201         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
 202
 203         memset(smb3_signature, 0x0, SMB2_CMACAES_SIZE);
 204         memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
 205
 206         rc = crypto_shash_setkey(server->secmech.cmacaes,
 207                 server->smb3signingkey, SMB2_CMACAES_SIZE);
 208         if (rc) {
 209                 cifs_dbg(VFS, "%s: Could not set key for cmac aes\n", __func__);
 210                 return rc;
 211         }
 212
 213         rc = crypto_shash_init(&server->secmech.sdesccmacaes->shash);
 214         if (rc) {
 215                 cifs_dbg(VFS, "%s: Could not init cmac aes\n", __func__);
 216                 return rc;
 217         }
 218
 219         for (i = 0; i < n_vec; i++) {
 220                 if (iov[i].iov_len == 0)
 221                         continue;
 222                 if (iov[i].iov_base == NULL) {
 223                         cifs_dbg(VFS, "null iovec entry");
 224                         return -EIO;
 225                 }
 226                 /*
 227                  * The first entry includes a length field (which does not get
 228                  * signed that occupies the first 4 bytes before the header).
 229                  */
 230                 if (i == 0) {
 231                         if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
 232                                 break; /* nothing to sign or corrupt header */
 233                         rc =
 234                         crypto_shash_update(
 235                                 &server->secmech.sdesccmacaes->shash,
 236                                 iov[i].iov_base + 4, iov[i].iov_len - 4);
 237                 } else {
 238                         rc =
 239                         crypto_shash_update(
 240                                 &server->secmech.sdesccmacaes->shash,
 241                                 iov[i].iov_base, iov[i].iov_len);
 242                 }
 243                 if (rc) {
 244                         cifs_dbg(VFS, "%s: Couldn't update cmac aes with payload\n",
 245                                                         __func__);
 246                         return rc;
 247                 }
 248         }
 249
 250         /* now hash over the rq_pages array */
 251         for (i = 0; i < rqst->rq_npages; i++) {
 252                 struct kvec p_iov;
 253
 254                 cifs_rqst_page_to_kvec(rqst, i, &p_iov);
 255                 crypto_shash_update(&server->secmech.sdesccmacaes->shash,
 256                                         p_iov.iov_base, p_iov.iov_len);
 257                 kunmap(rqst->rq_pages[i]);
 258         }
 259
 260         rc = crypto_shash_final(&server->secmech.sdesccmacaes->shash,
 261                                                 sigptr);
 262         if (rc)
 263                 cifs_dbg(VFS, "%s: Could not generate cmac aes\n", __func__);
 264
 265         memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
 266
 267         return rc;
 268 }
 269
 270 /* must be called with server->srv_mutex held */
 271 static int
 272 smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 273 {
 274         int rc = 0;
 275         struct smb2_hdr *smb2_pdu = rqst->rq_iov[0].iov_base;
 276
 277         if (!(smb2_pdu->Flags & SMB2_FLAGS_SIGNED) ||
 278             server->tcpStatus == CifsNeedNegotiate)
 279                 return rc;
 280
 281         if (!server->session_estab) {
 282                 strncpy(smb2_pdu->Signature, "BSRSPYL", 8);
 283                 return rc;
 284         }
 285
 286         rc = server->ops->calc_signature(rqst, server);
 287
 288         return rc;
 289 }
 290
 291 int
 292 smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 293 {
 294         unsigned int rc;
 295         char server_response_sig[16];
 296         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 297
 298         if ((smb2_pdu->Command == SMB2_NEGOTIATE) ||
 299             (smb2_pdu->Command == SMB2_OPLOCK_BREAK) ||
 300             (!server->session_estab))
 301                 return 0;
 302
 303         /*
 304          * BB what if signatures are supposed to be on for session but
 305          * server does not send one? BB
 306          */
 307
 308         /* Do not need to verify session setups with signature "BSRSPYL " */
 309         if (memcmp(smb2_pdu->Signature, "BSRSPYL ", 8) == 0)
 310                 cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
 311                          smb2_pdu->Command);
 312
 313         /*
 314          * Save off the origiginal signature so we can modify the smb and check
 315          * our calculated signature against what the server sent.
 316          */
 317         memcpy(server_response_sig, smb2_pdu->Signature, SMB2_SIGNATURE_SIZE);
 318
 319         memset(smb2_pdu->Signature, 0, SMB2_SIGNATURE_SIZE);
 320
 321         mutex_lock(&server->srv_mutex);
 322         rc = server->ops->calc_signature(rqst, server);
 323         mutex_unlock(&server->srv_mutex);
 324
 325         if (rc)
 326                 return rc;
 327
 328         if (memcmp(server_response_sig, smb2_pdu->Signature,
 329                    SMB2_SIGNATURE_SIZE))
 330                 return -EACCES;
 331         else
 332                 return 0;
 333 }
 334
 335 /*
 336  * Set message id for the request. Should be called after wait_for_free_request
 337  * and when srv_mutex is held.
 338  */
 339 static inline void
 340 smb2_seq_num_into_buf(struct TCP_Server_Info *server, struct smb2_hdr *hdr)
 341 {
 342         hdr->MessageId = get_next_mid(server);
 343 }
 344
 345 static struct mid_q_entry *
 346 smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
 347                      struct TCP_Server_Info *server)
 348 {
 349         struct mid_q_entry *temp;
 350
 351         if (server == NULL) {
 352                 cifs_dbg(VFS, "Null TCP session in smb2_mid_entry_alloc\n");
 353                 return NULL;
 354         }
 355
 356         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
 357         if (temp == NULL)
 358                 return temp;
 359         else {
 360                 memset(temp, 0, sizeof(struct mid_q_entry));
 361                 temp->mid = smb_buffer->MessageId;      /* always LE */
 362                 temp->pid = current->pid;
 363                 temp->command = smb_buffer->Command;    /* Always LE */
 364                 temp->when_alloc = jiffies;
 365                 temp->server = server;
 366
 367                 /*
 368                  * The default is for the mid to be synchronous, so the
 369                  * default callback just wakes up the current task.
 370                  */
 371                 temp->callback = cifs_wake_up_task;
 372                 temp->callback_data = current;
 373         }
 374
 375         atomic_inc(&midCount);
 376         temp->mid_state = MID_REQUEST_ALLOCATED;
 377         return temp;
 378 }
 379
 380 static int
 381 smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
 382                    struct mid_q_entry **mid)
 383 {
 384         if (ses->server->tcpStatus == CifsExiting)
 385                 return -ENOENT;
 386
 387         if (ses->server->tcpStatus == CifsNeedReconnect) {
 388                 cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
 389                 return -EAGAIN;
 390         }
 391
 392         if (ses->status != CifsGood) {
 393                 /* check if SMB2 session is bad because we are setting it up */
 394                 if ((buf->Command != SMB2_SESSION_SETUP) &&
 395                     (buf->Command != SMB2_NEGOTIATE))
 396                         return -EAGAIN;
 397                 /* else ok - we are setting up session */
 398         }
 399         *mid = smb2_mid_entry_alloc(buf, ses->server);
 400         if (*mid == NULL)
 401                 return -ENOMEM;
 402         spin_lock(&GlobalMid_Lock);
 403         list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
 404         spin_unlock(&GlobalMid_Lock);
 405         return 0;
 406 }
 407
 408 int
 409 smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 410                    bool log_error)
 411 {
 412         unsigned int len = get_rfc1002_length(mid->resp_buf);
 413         struct kvec iov;
 414         struct smb_rqst rqst = { .rq_iov = &iov,
 415                                  .rq_nvec = 1 };
 416
 417         iov.iov_base = (char *)mid->resp_buf;
 418         iov.iov_len = get_rfc1002_length(mid->resp_buf) + 4;
 419
 420         dump_smb(mid->resp_buf, min_t(u32, 80, len));
 421         /* convert the length into a more usable form */
 422         if (len > 24 && server->sign) {
 423                 int rc;
 424
 425                 rc = smb2_verify_signature(&rqst, server);
 426                 if (rc)
 427                         cifs_dbg(VFS, "SMB signature verification returned error = %d\n",
 428                                  rc);
 429         }
 430
 431         return map_smb2_to_linux_error(mid->resp_buf, log_error);
 432 }
 433
 434 struct mid_q_entry *
 435 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
 436 {
 437         int rc;
 438         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 439         struct mid_q_entry *mid;
 440
 441         smb2_seq_num_into_buf(ses->server, hdr);
 442
 443         rc = smb2_get_mid_entry(ses, hdr, &mid);
 444         if (rc)
 445                 return ERR_PTR(rc);
 446         rc = smb2_sign_rqst(rqst, ses->server);
 447         if (rc) {
 448                 cifs_delete_mid(mid);
 449                 return ERR_PTR(rc);
 450         }
 451         return mid;
 452 }
 453
 454 struct mid_q_entry *
 455 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 456 {
 457         int rc;
 458         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 459         struct mid_q_entry *mid;
 460
 461         smb2_seq_num_into_buf(server, hdr);
 462
 463         mid = smb2_mid_entry_alloc(hdr, server);
 464         if (mid == NULL)
 465                 return ERR_PTR(-ENOMEM);
 466
 467         rc = smb2_sign_rqst(rqst, server);
 468         if (rc) {
 469                 DeleteMidQEntry(mid);
 470                 return ERR_PTR(rc);
 471         }
 472
 473         return mid;
 474 }