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_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                 cERROR(1, "%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                 cERROR(1, "%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                         cERROR(1, "null iovec entry");
  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                         cERROR(1, "%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                 cERROR(1, "%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 /* must be called with server->srv_mutex held */
 120 static int
 121 smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 122 {
 123         int rc = 0;
 124         struct smb2_hdr *smb2_pdu = rqst->rq_iov[0].iov_base;
 125
 126         if (!(smb2_pdu->Flags & SMB2_FLAGS_SIGNED) ||
 127             server->tcpStatus == CifsNeedNegotiate)
 128                 return rc;
 129
 130         if (!server->session_estab) {
 131                 strncpy(smb2_pdu->Signature, "BSRSPYL", 8);
 132                 return rc;
 133         }
 134
 135         rc = smb2_calc_signature(rqst, server);
 136
 137         return rc;
 138 }
 139
 140 int
 141 smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 142 {
 143         unsigned int rc;
 144         char server_response_sig[16];
 145         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 146
 147         if ((smb2_pdu->Command == SMB2_NEGOTIATE) ||
 148             (smb2_pdu->Command == SMB2_OPLOCK_BREAK) ||
 149             (!server->session_estab))
 150                 return 0;
 151
 152         /*
 153          * BB what if signatures are supposed to be on for session but
 154          * server does not send one? BB
 155          */
 156
 157         /* Do not need to verify session setups with signature "BSRSPYL " */
 158         if (memcmp(smb2_pdu->Signature, "BSRSPYL ", 8) == 0)
 159                 cFYI(1, "dummy signature received for smb command 0x%x",
 160                         smb2_pdu->Command);
 161
 162         /*
 163          * Save off the origiginal signature so we can modify the smb and check
 164          * our calculated signature against what the server sent.
 165          */
 166         memcpy(server_response_sig, smb2_pdu->Signature, SMB2_SIGNATURE_SIZE);
 167
 168         memset(smb2_pdu->Signature, 0, SMB2_SIGNATURE_SIZE);
 169
 170         mutex_lock(&server->srv_mutex);
 171         rc = smb2_calc_signature(rqst, server);
 172         mutex_unlock(&server->srv_mutex);
 173
 174         if (rc)
 175                 return rc;
 176
 177         if (memcmp(server_response_sig, smb2_pdu->Signature,
 178                    SMB2_SIGNATURE_SIZE))
 179                 return -EACCES;
 180         else
 181                 return 0;
 182 }
 183
 184 /*
 185  * Set message id for the request. Should be called after wait_for_free_request
 186  * and when srv_mutex is held.
 187  */
 188 static inline void
 189 smb2_seq_num_into_buf(struct TCP_Server_Info *server, struct smb2_hdr *hdr)
 190 {
 191         hdr->MessageId = get_next_mid(server);
 192 }
 193
 194 static struct mid_q_entry *
 195 smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
 196                      struct TCP_Server_Info *server)
 197 {
 198         struct mid_q_entry *temp;
 199
 200         if (server == NULL) {
 201                 cERROR(1, "Null TCP session in smb2_mid_entry_alloc");
 202                 return NULL;
 203         }
 204
 205         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
 206         if (temp == NULL)
 207                 return temp;
 208         else {
 209                 memset(temp, 0, sizeof(struct mid_q_entry));
 210                 temp->mid = smb_buffer->MessageId;      /* always LE */
 211                 temp->pid = current->pid;
 212                 temp->command = smb_buffer->Command;    /* Always LE */
 213                 temp->when_alloc = jiffies;
 214                 temp->server = server;
 215
 216                 /*
 217                  * The default is for the mid to be synchronous, so the
 218                  * default callback just wakes up the current task.
 219                  */
 220                 temp->callback = cifs_wake_up_task;
 221                 temp->callback_data = current;
 222         }
 223
 224         atomic_inc(&midCount);
 225         temp->mid_state = MID_REQUEST_ALLOCATED;
 226         return temp;
 227 }
 228
 229 static int
 230 smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
 231                    struct mid_q_entry **mid)
 232 {
 233         if (ses->server->tcpStatus == CifsExiting)
 234                 return -ENOENT;
 235
 236         if (ses->server->tcpStatus == CifsNeedReconnect) {
 237                 cFYI(1, "tcp session dead - return to caller to retry");
 238                 return -EAGAIN;
 239         }
 240
 241         if (ses->status != CifsGood) {
 242                 /* check if SMB2 session is bad because we are setting it up */
 243                 if ((buf->Command != SMB2_SESSION_SETUP) &&
 244                     (buf->Command != SMB2_NEGOTIATE))
 245                         return -EAGAIN;
 246                 /* else ok - we are setting up session */
 247         }
 248         *mid = smb2_mid_entry_alloc(buf, ses->server);
 249         if (*mid == NULL)
 250                 return -ENOMEM;
 251         spin_lock(&GlobalMid_Lock);
 252         list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
 253         spin_unlock(&GlobalMid_Lock);
 254         return 0;
 255 }
 256
 257 int
 258 smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 259                    bool log_error)
 260 {
 261         unsigned int len = get_rfc1002_length(mid->resp_buf);
 262         struct kvec iov;
 263         struct smb_rqst rqst = { .rq_iov = &iov,
 264                                  .rq_nvec = 1 };
 265
 266         iov.iov_base = (char *)mid->resp_buf;
 267         iov.iov_len = get_rfc1002_length(mid->resp_buf) + 4;
 268
 269         dump_smb(mid->resp_buf, min_t(u32, 80, len));
 270         /* convert the length into a more usable form */
 271         if ((len > 24) &&
 272             (server->sec_mode & (SECMODE_SIGN_REQUIRED|SECMODE_SIGN_ENABLED))) {
 273                 int rc;
 274
 275                 rc = smb2_verify_signature(&rqst, server);
 276                 if (rc)
 277                         cERROR(1, "SMB signature verification returned error = "
 278                                "%d", rc);
 279         }
 280
 281         return map_smb2_to_linux_error(mid->resp_buf, log_error);
 282 }
 283
 284 struct mid_q_entry *
 285 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
 286 {
 287         int rc;
 288         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 289         struct mid_q_entry *mid;
 290
 291         smb2_seq_num_into_buf(ses->server, hdr);
 292
 293         rc = smb2_get_mid_entry(ses, hdr, &mid);
 294         if (rc)
 295                 return ERR_PTR(rc);
 296         rc = smb2_sign_rqst(rqst, ses->server);
 297         if (rc) {
 298                 cifs_delete_mid(mid);
 299                 return ERR_PTR(rc);
 300         }
 301         return mid;
 302 }
 303
 304 struct mid_q_entry *
 305 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 306 {
 307         int rc;
 308         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 309         struct mid_q_entry *mid;
 310
 311         smb2_seq_num_into_buf(server, hdr);
 312
 313         mid = smb2_mid_entry_alloc(hdr, server);
 314         if (mid == NULL)
 315                 return ERR_PTR(-ENOMEM);
 316
 317         rc = smb2_sign_rqst(rqst, server);
 318         if (rc) {
 319                 DeleteMidQEntry(mid);
 320                 return ERR_PTR(rc);
 321         }
 322
 323         return mid;
 324 }