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                 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 int
 120 smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 121 {
 122         cFYI(1, "smb3 signatures not supported yet");
 123         return -EOPNOTSUPP;
 124 }
 125
 126 /* must be called with server->srv_mutex held */
 127 static int
 128 smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 129 {
 130         int rc = 0;
 131         struct smb2_hdr *smb2_pdu = rqst->rq_iov[0].iov_base;
 132
 133         if (!(smb2_pdu->Flags & SMB2_FLAGS_SIGNED) ||
 134             server->tcpStatus == CifsNeedNegotiate)
 135                 return rc;
 136
 137         if (!server->session_estab) {
 138                 strncpy(smb2_pdu->Signature, "BSRSPYL", 8);
 139                 return rc;
 140         }
 141
 142         rc = server->ops->calc_signature(rqst, server);
 143
 144         return rc;
 145 }
 146
 147 int
 148 smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 149 {
 150         unsigned int rc;
 151         char server_response_sig[16];
 152         struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 153
 154         if ((smb2_pdu->Command == SMB2_NEGOTIATE) ||
 155             (smb2_pdu->Command == SMB2_OPLOCK_BREAK) ||
 156             (!server->session_estab))
 157                 return 0;
 158
 159         /*
 160          * BB what if signatures are supposed to be on for session but
 161          * server does not send one? BB
 162          */
 163
 164         /* Do not need to verify session setups with signature "BSRSPYL " */
 165         if (memcmp(smb2_pdu->Signature, "BSRSPYL ", 8) == 0)
 166                 cFYI(1, "dummy signature received for smb command 0x%x",
 167                         smb2_pdu->Command);
 168
 169         /*
 170          * Save off the origiginal signature so we can modify the smb and check
 171          * our calculated signature against what the server sent.
 172          */
 173         memcpy(server_response_sig, smb2_pdu->Signature, SMB2_SIGNATURE_SIZE);
 174
 175         memset(smb2_pdu->Signature, 0, SMB2_SIGNATURE_SIZE);
 176
 177         mutex_lock(&server->srv_mutex);
 178         rc = server->ops->calc_signature(rqst, server);
 179         mutex_unlock(&server->srv_mutex);
 180
 181         if (rc)
 182                 return rc;
 183
 184         if (memcmp(server_response_sig, smb2_pdu->Signature,
 185                    SMB2_SIGNATURE_SIZE))
 186                 return -EACCES;
 187         else
 188                 return 0;
 189 }
 190
 191 /*
 192  * Set message id for the request. Should be called after wait_for_free_request
 193  * and when srv_mutex is held.
 194  */
 195 static inline void
 196 smb2_seq_num_into_buf(struct TCP_Server_Info *server, struct smb2_hdr *hdr)
 197 {
 198         hdr->MessageId = get_next_mid(server);
 199 }
 200
 201 static struct mid_q_entry *
 202 smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
 203                      struct TCP_Server_Info *server)
 204 {
 205         struct mid_q_entry *temp;
 206
 207         if (server == NULL) {
 208                 cERROR(1, "Null TCP session in smb2_mid_entry_alloc");
 209                 return NULL;
 210         }
 211
 212         temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
 213         if (temp == NULL)
 214                 return temp;
 215         else {
 216                 memset(temp, 0, sizeof(struct mid_q_entry));
 217                 temp->mid = smb_buffer->MessageId;      /* always LE */
 218                 temp->pid = current->pid;
 219                 temp->command = smb_buffer->Command;    /* Always LE */
 220                 temp->when_alloc = jiffies;
 221                 temp->server = server;
 222
 223                 /*
 224                  * The default is for the mid to be synchronous, so the
 225                  * default callback just wakes up the current task.
 226                  */
 227                 temp->callback = cifs_wake_up_task;
 228                 temp->callback_data = current;
 229         }
 230
 231         atomic_inc(&midCount);
 232         temp->mid_state = MID_REQUEST_ALLOCATED;
 233         return temp;
 234 }
 235
 236 static int
 237 smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
 238                    struct mid_q_entry **mid)
 239 {
 240         if (ses->server->tcpStatus == CifsExiting)
 241                 return -ENOENT;
 242
 243         if (ses->server->tcpStatus == CifsNeedReconnect) {
 244                 cFYI(1, "tcp session dead - return to caller to retry");
 245                 return -EAGAIN;
 246         }
 247
 248         if (ses->status != CifsGood) {
 249                 /* check if SMB2 session is bad because we are setting it up */
 250                 if ((buf->Command != SMB2_SESSION_SETUP) &&
 251                     (buf->Command != SMB2_NEGOTIATE))
 252                         return -EAGAIN;
 253                 /* else ok - we are setting up session */
 254         }
 255         *mid = smb2_mid_entry_alloc(buf, ses->server);
 256         if (*mid == NULL)
 257                 return -ENOMEM;
 258         spin_lock(&GlobalMid_Lock);
 259         list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
 260         spin_unlock(&GlobalMid_Lock);
 261         return 0;
 262 }
 263
 264 int
 265 smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 266                    bool log_error)
 267 {
 268         unsigned int len = get_rfc1002_length(mid->resp_buf);
 269         struct kvec iov;
 270         struct smb_rqst rqst = { .rq_iov = &iov,
 271                                  .rq_nvec = 1 };
 272
 273         iov.iov_base = (char *)mid->resp_buf;
 274         iov.iov_len = get_rfc1002_length(mid->resp_buf) + 4;
 275
 276         dump_smb(mid->resp_buf, min_t(u32, 80, len));
 277         /* convert the length into a more usable form */
 278         if ((len > 24) &&
 279             (server->sec_mode & (SECMODE_SIGN_REQUIRED|SECMODE_SIGN_ENABLED))) {
 280                 int rc;
 281
 282                 rc = smb2_verify_signature(&rqst, server);
 283                 if (rc)
 284                         cERROR(1, "SMB signature verification returned error = "
 285                                "%d", rc);
 286         }
 287
 288         return map_smb2_to_linux_error(mid->resp_buf, log_error);
 289 }
 290
 291 struct mid_q_entry *
 292 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
 293 {
 294         int rc;
 295         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 296         struct mid_q_entry *mid;
 297
 298         smb2_seq_num_into_buf(ses->server, hdr);
 299
 300         rc = smb2_get_mid_entry(ses, hdr, &mid);
 301         if (rc)
 302                 return ERR_PTR(rc);
 303         rc = smb2_sign_rqst(rqst, ses->server);
 304         if (rc) {
 305                 cifs_delete_mid(mid);
 306                 return ERR_PTR(rc);
 307         }
 308         return mid;
 309 }
 310
 311 struct mid_q_entry *
 312 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
 313 {
 314         int rc;
 315         struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
 316         struct mid_q_entry *mid;
 317
 318         smb2_seq_num_into_buf(server, hdr);
 319
 320         mid = smb2_mid_entry_alloc(hdr, server);
 321         if (mid == NULL)
 322                 return ERR_PTR(-ENOMEM);
 323
 324         rc = smb2_sign_rqst(rqst, server);
 325         if (rc) {
 326                 DeleteMidQEntry(mid);
 327                 return ERR_PTR(rc);
 328         }
 329
 330         return mid;
 331 }