fs/cifs/misc.c

   1 /*
   2  *   fs/cifs/misc.c
   3  *
   4  *   Copyright (C) International Business Machines  Corp., 2002,2008
   5  *   Author(s): Steve French (sfrench@us.ibm.com)
   6  *
   7  *   This library is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU Lesser General Public License as published
   9  *   by the Free Software Foundation; either version 2.1 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This library is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  15  *   the GNU Lesser General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU Lesser General Public License
  18  *   along with this library; if not, write to the Free Software
  19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21
  22 #include <linux/slab.h>
  23 #include <linux/ctype.h>
  24 #include <linux/mempool.h>
  25 #include "cifspdu.h"
  26 #include "cifsglob.h"
  27 #include "cifsproto.h"
  28 #include "cifs_debug.h"
  29 #include "smberr.h"
  30 #include "nterr.h"
  31 #include "cifs_unicode.h"
  32 #ifdef CONFIG_CIFS_SMB2
  33 #include "smb2pdu.h"
  34 #endif
  35
  36 extern mempool_t *cifs_sm_req_poolp;
  37 extern mempool_t *cifs_req_poolp;
  38
  39 /* The xid serves as a useful identifier for each incoming vfs request,
  40    in a similar way to the mid which is useful to track each sent smb,
  41    and CurrentXid can also provide a running counter (although it
  42    will eventually wrap past zero) of the total vfs operations handled
  43    since the cifs fs was mounted */
  44
  45 unsigned int
  46 _get_xid(void)
  47 {
  48         unsigned int xid;
  49
  50         spin_lock(&GlobalMid_Lock);
  51         GlobalTotalActiveXid++;
  52
  53         /* keep high water mark for number of simultaneous ops in filesystem */
  54         if (GlobalTotalActiveXid > GlobalMaxActiveXid)
  55                 GlobalMaxActiveXid = GlobalTotalActiveXid;
  56         if (GlobalTotalActiveXid > 65000)
  57                 cFYI(1, "warning: more than 65000 requests active");
  58         xid = GlobalCurrentXid++;
  59         spin_unlock(&GlobalMid_Lock);
  60         return xid;
  61 }
  62
  63 void
  64 _free_xid(unsigned int xid)
  65 {
  66         spin_lock(&GlobalMid_Lock);
  67         /* if (GlobalTotalActiveXid == 0)
  68                 BUG(); */
  69         GlobalTotalActiveXid--;
  70         spin_unlock(&GlobalMid_Lock);
  71 }
  72
  73 struct cifs_ses *
  74 sesInfoAlloc(void)
  75 {
  76         struct cifs_ses *ret_buf;
  77
  78         ret_buf = kzalloc(sizeof(struct cifs_ses), GFP_KERNEL);
  79         if (ret_buf) {
  80                 atomic_inc(&sesInfoAllocCount);
  81                 ret_buf->status = CifsNew;
  82                 ++ret_buf->ses_count;
  83                 INIT_LIST_HEAD(&ret_buf->smb_ses_list);
  84                 INIT_LIST_HEAD(&ret_buf->tcon_list);
  85                 mutex_init(&ret_buf->session_mutex);
  86         }
  87         return ret_buf;
  88 }
  89
  90 void
  91 sesInfoFree(struct cifs_ses *buf_to_free)
  92 {
  93         if (buf_to_free == NULL) {
  94                 cFYI(1, "Null buffer passed to sesInfoFree");
  95                 return;
  96         }
  97
  98         atomic_dec(&sesInfoAllocCount);
  99         kfree(buf_to_free->serverOS);
 100         kfree(buf_to_free->serverDomain);
 101         kfree(buf_to_free->serverNOS);
 102         if (buf_to_free->password) {
 103                 memset(buf_to_free->password, 0, strlen(buf_to_free->password));
 104                 kfree(buf_to_free->password);
 105         }
 106         kfree(buf_to_free->user_name);
 107         kfree(buf_to_free->domainName);
 108         kfree(buf_to_free);
 109 }
 110
 111 struct cifs_tcon *
 112 tconInfoAlloc(void)
 113 {
 114         struct cifs_tcon *ret_buf;
 115         ret_buf = kzalloc(sizeof(struct cifs_tcon), GFP_KERNEL);
 116         if (ret_buf) {
 117                 atomic_inc(&tconInfoAllocCount);
 118                 ret_buf->tidStatus = CifsNew;
 119                 ++ret_buf->tc_count;
 120                 INIT_LIST_HEAD(&ret_buf->openFileList);
 121                 INIT_LIST_HEAD(&ret_buf->tcon_list);
 122 #ifdef CONFIG_CIFS_STATS
 123                 spin_lock_init(&ret_buf->stat_lock);
 124 #endif
 125         }
 126         return ret_buf;
 127 }
 128
 129 void
 130 tconInfoFree(struct cifs_tcon *buf_to_free)
 131 {
 132         if (buf_to_free == NULL) {
 133                 cFYI(1, "Null buffer passed to tconInfoFree");
 134                 return;
 135         }
 136         atomic_dec(&tconInfoAllocCount);
 137         kfree(buf_to_free->nativeFileSystem);
 138         if (buf_to_free->password) {
 139                 memset(buf_to_free->password, 0, strlen(buf_to_free->password));
 140                 kfree(buf_to_free->password);
 141         }
 142         kfree(buf_to_free);
 143 }
 144
 145 struct smb_hdr *
 146 cifs_buf_get(void)
 147 {
 148         struct smb_hdr *ret_buf = NULL;
 149         size_t buf_size = sizeof(struct smb_hdr);
 150
 151 #ifdef CONFIG_CIFS_SMB2
 152         /*
 153          * SMB2 header is bigger than CIFS one - no problems to clean some
 154          * more bytes for CIFS.
 155          */
 156         buf_size = sizeof(struct smb2_hdr);
 157 #endif
 158         /*
 159          * We could use negotiated size instead of max_msgsize -
 160          * but it may be more efficient to always alloc same size
 161          * albeit slightly larger than necessary and maxbuffersize
 162          * defaults to this and can not be bigger.
 163          */
 164         ret_buf = mempool_alloc(cifs_req_poolp, GFP_NOFS);
 165
 166         /* clear the first few header bytes */
 167         /* for most paths, more is cleared in header_assemble */
 168         if (ret_buf) {
 169                 memset(ret_buf, 0, buf_size + 3);
 170                 atomic_inc(&bufAllocCount);
 171 #ifdef CONFIG_CIFS_STATS2
 172                 atomic_inc(&totBufAllocCount);
 173 #endif /* CONFIG_CIFS_STATS2 */
 174         }
 175
 176         return ret_buf;
 177 }
 178
 179 void
 180 cifs_buf_release(void *buf_to_free)
 181 {
 182         if (buf_to_free == NULL) {
 183                 /* cFYI(1, "Null buffer passed to cifs_buf_release");*/
 184                 return;
 185         }
 186         mempool_free(buf_to_free, cifs_req_poolp);
 187
 188         atomic_dec(&bufAllocCount);
 189         return;
 190 }
 191
 192 struct smb_hdr *
 193 cifs_small_buf_get(void)
 194 {
 195         struct smb_hdr *ret_buf = NULL;
 196
 197 /* We could use negotiated size instead of max_msgsize -
 198    but it may be more efficient to always alloc same size
 199    albeit slightly larger than necessary and maxbuffersize
 200    defaults to this and can not be bigger */
 201         ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
 202         if (ret_buf) {
 203         /* No need to clear memory here, cleared in header assemble */
 204         /*      memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
 205                 atomic_inc(&smBufAllocCount);
 206 #ifdef CONFIG_CIFS_STATS2
 207                 atomic_inc(&totSmBufAllocCount);
 208 #endif /* CONFIG_CIFS_STATS2 */
 209
 210         }
 211         return ret_buf;
 212 }
 213
 214 void
 215 cifs_small_buf_release(void *buf_to_free)
 216 {
 217
 218         if (buf_to_free == NULL) {
 219                 cFYI(1, "Null buffer passed to cifs_small_buf_release");
 220                 return;
 221         }
 222         mempool_free(buf_to_free, cifs_sm_req_poolp);
 223
 224         atomic_dec(&smBufAllocCount);
 225         return;
 226 }
 227
 228 /* NB: MID can not be set if treeCon not passed in, in that
 229    case it is responsbility of caller to set the mid */
 230 void
 231 header_assemble(struct smb_hdr *buffer, char smb_command /* command */ ,
 232                 const struct cifs_tcon *treeCon, int word_count
 233                 /* length of fixed section (word count) in two byte units  */)
 234 {
 235         char *temp = (char *) buffer;
 236
 237         memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */
 238
 239         buffer->smb_buf_length = cpu_to_be32(
 240             (2 * word_count) + sizeof(struct smb_hdr) -
 241             4 /*  RFC 1001 length field does not count */  +
 242             2 /* for bcc field itself */) ;
 243
 244         buffer->Protocol[0] = 0xFF;
 245         buffer->Protocol[1] = 'S';
 246         buffer->Protocol[2] = 'M';
 247         buffer->Protocol[3] = 'B';
 248         buffer->Command = smb_command;
 249         buffer->Flags = 0x00;   /* case sensitive */
 250         buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
 251         buffer->Pid = cpu_to_le16((__u16)current->tgid);
 252         buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
 253         if (treeCon) {
 254                 buffer->Tid = treeCon->tid;
 255                 if (treeCon->ses) {
 256                         if (treeCon->ses->capabilities & CAP_UNICODE)
 257                                 buffer->Flags2 |= SMBFLG2_UNICODE;
 258                         if (treeCon->ses->capabilities & CAP_STATUS32)
 259                                 buffer->Flags2 |= SMBFLG2_ERR_STATUS;
 260
 261                         /* Uid is not converted */
 262                         buffer->Uid = treeCon->ses->Suid;
 263                         buffer->Mid = get_next_mid(treeCon->ses->server);
 264                 }
 265                 if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
 266                         buffer->Flags2 |= SMBFLG2_DFS;
 267                 if (treeCon->nocase)
 268                         buffer->Flags  |= SMBFLG_CASELESS;
 269                 if ((treeCon->ses) && (treeCon->ses->server))
 270                         if (treeCon->ses->server->sec_mode &
 271                           (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
 272                                 buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
 273         }
 274
 275 /*  endian conversion of flags is now done just before sending */
 276         buffer->WordCount = (char) word_count;
 277         return;
 278 }
 279
 280 static int
 281 check_smb_hdr(struct smb_hdr *smb, __u16 mid)
 282 {
 283         /* does it have the right SMB "signature" ? */
 284         if (*(__le32 *) smb->Protocol != cpu_to_le32(0x424d53ff)) {
 285                 cERROR(1, "Bad protocol string signature header 0x%x",
 286                         *(unsigned int *)smb->Protocol);
 287                 return 1;
 288         }
 289
 290         /* Make sure that message ids match */
 291         if (mid != smb->Mid) {
 292                 cERROR(1, "Mids do not match. received=%u expected=%u",
 293                         smb->Mid, mid);
 294                 return 1;
 295         }
 296
 297         /* if it's a response then accept */
 298         if (smb->Flags & SMBFLG_RESPONSE)
 299                 return 0;
 300
 301         /* only one valid case where server sends us request */
 302         if (smb->Command == SMB_COM_LOCKING_ANDX)
 303                 return 0;
 304
 305         cERROR(1, "Server sent request, not response. mid=%u", smb->Mid);
 306         return 1;
 307 }
 308
 309 int
 310 checkSMB(char *buf, unsigned int total_read)
 311 {
 312         struct smb_hdr *smb = (struct smb_hdr *)buf;
 313         __u16 mid = smb->Mid;
 314         __u32 rfclen = be32_to_cpu(smb->smb_buf_length);
 315         __u32 clc_len;  /* calculated length */
 316         cFYI(0, "checkSMB Length: 0x%x, smb_buf_length: 0x%x",
 317                 total_read, rfclen);
 318
 319         /* is this frame too small to even get to a BCC? */
 320         if (total_read < 2 + sizeof(struct smb_hdr)) {
 321                 if ((total_read >= sizeof(struct smb_hdr) - 1)
 322                             && (smb->Status.CifsError != 0)) {
 323                         /* it's an error return */
 324                         smb->WordCount = 0;
 325                         /* some error cases do not return wct and bcc */
 326                         return 0;
 327                 } else if ((total_read == sizeof(struct smb_hdr) + 1) &&
 328                                 (smb->WordCount == 0)) {
 329                         char *tmp = (char *)smb;
 330                         /* Need to work around a bug in two servers here */
 331                         /* First, check if the part of bcc they sent was zero */
 332                         if (tmp[sizeof(struct smb_hdr)] == 0) {
 333                                 /* some servers return only half of bcc
 334                                  * on simple responses (wct, bcc both zero)
 335                                  * in particular have seen this on
 336                                  * ulogoffX and FindClose. This leaves
 337                                  * one byte of bcc potentially unitialized
 338                                  */
 339                                 /* zero rest of bcc */
 340                                 tmp[sizeof(struct smb_hdr)+1] = 0;
 341                                 return 0;
 342                         }
 343                         cERROR(1, "rcvd invalid byte count (bcc)");
 344                 } else {
 345                         cERROR(1, "Length less than smb header size");
 346                 }
 347                 return -EIO;
 348         }
 349
 350         /* otherwise, there is enough to get to the BCC */
 351         if (check_smb_hdr(smb, mid))
 352                 return -EIO;
 353         clc_len = smbCalcSize(smb);
 354
 355         if (4 + rfclen != total_read) {
 356                 cERROR(1, "Length read does not match RFC1001 length %d",
 357                                 rfclen);
 358                 return -EIO;
 359         }
 360
 361         if (4 + rfclen != clc_len) {
 362                 /* check if bcc wrapped around for large read responses */
 363                 if ((rfclen > 64 * 1024) && (rfclen > clc_len)) {
 364                         /* check if lengths match mod 64K */
 365                         if (((4 + rfclen) & 0xFFFF) == (clc_len & 0xFFFF))
 366                                 return 0; /* bcc wrapped */
 367                 }
 368                 cFYI(1, "Calculated size %u vs length %u mismatch for mid=%u",
 369                                 clc_len, 4 + rfclen, smb->Mid);
 370
 371                 if (4 + rfclen < clc_len) {
 372                         cERROR(1, "RFC1001 size %u smaller than SMB for mid=%u",
 373                                         rfclen, smb->Mid);
 374                         return -EIO;
 375                 } else if (rfclen > clc_len + 512) {
 376                         /*
 377                          * Some servers (Windows XP in particular) send more
 378                          * data than the lengths in the SMB packet would
 379                          * indicate on certain calls (byte range locks and
 380                          * trans2 find first calls in particular). While the
 381                          * client can handle such a frame by ignoring the
 382                          * trailing data, we choose limit the amount of extra
 383                          * data to 512 bytes.
 384                          */
 385                         cERROR(1, "RFC1001 size %u more than 512 bytes larger "
 386                                   "than SMB for mid=%u", rfclen, smb->Mid);
 387                         return -EIO;
 388                 }
 389         }
 390         return 0;
 391 }
 392
 393 bool
 394 is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
 395 {
 396         struct smb_hdr *buf = (struct smb_hdr *)buffer;
 397         struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
 398         struct list_head *tmp, *tmp1, *tmp2;
 399         struct cifs_ses *ses;
 400         struct cifs_tcon *tcon;
 401         struct cifsInodeInfo *pCifsInode;
 402         struct cifsFileInfo *netfile;
 403
 404         cFYI(1, "Checking for oplock break or dnotify response");
 405         if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
 406            (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
 407                 struct smb_com_transaction_change_notify_rsp *pSMBr =
 408                         (struct smb_com_transaction_change_notify_rsp *)buf;
 409                 struct file_notify_information *pnotify;
 410                 __u32 data_offset = 0;
 411                 if (get_bcc(buf) > sizeof(struct file_notify_information)) {
 412                         data_offset = le32_to_cpu(pSMBr->DataOffset);
 413
 414                         pnotify = (struct file_notify_information *)
 415                                 ((char *)&pSMBr->hdr.Protocol + data_offset);
 416                         cFYI(1, "dnotify on %s Action: 0x%x",
 417                                  pnotify->FileName, pnotify->Action);
 418                         /*   cifs_dump_mem("Rcvd notify Data: ",buf,
 419                                 sizeof(struct smb_hdr)+60); */
 420                         return true;
 421                 }
 422                 if (pSMBr->hdr.Status.CifsError) {
 423                         cFYI(1, "notify err 0x%d",
 424                                 pSMBr->hdr.Status.CifsError);
 425                         return true;
 426                 }
 427                 return false;
 428         }
 429         if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 430                 return false;
 431         if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
 432                 /* no sense logging error on invalid handle on oplock
 433                    break - harmless race between close request and oplock
 434                    break response is expected from time to time writing out
 435                    large dirty files cached on the client */
 436                 if ((NT_STATUS_INVALID_HANDLE) ==
 437                    le32_to_cpu(pSMB->hdr.Status.CifsError)) {
 438                         cFYI(1, "invalid handle on oplock break");
 439                         return true;
 440                 } else if (ERRbadfid ==
 441                    le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
 442                         return true;
 443                 } else {
 444                         return false; /* on valid oplock brk we get "request" */
 445                 }
 446         }
 447         if (pSMB->hdr.WordCount != 8)
 448                 return false;
 449
 450         cFYI(1, "oplock type 0x%d level 0x%d",
 451                  pSMB->LockType, pSMB->OplockLevel);
 452         if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
 453                 return false;
 454
 455         /* look up tcon based on tid & uid */
 456         spin_lock(&cifs_tcp_ses_lock);
 457         list_for_each(tmp, &srv->smb_ses_list) {
 458                 ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
 459                 list_for_each(tmp1, &ses->tcon_list) {
 460                         tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 461                         if (tcon->tid != buf->Tid)
 462                                 continue;
 463
 464                         cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
 465                         spin_lock(&cifs_file_list_lock);
 466                         list_for_each(tmp2, &tcon->openFileList) {
 467                                 netfile = list_entry(tmp2, struct cifsFileInfo,
 468                                                      tlist);
 469                                 if (pSMB->Fid != netfile->netfid)
 470                                         continue;
 471
 472                                 cFYI(1, "file id match, oplock break");
 473                                 pCifsInode = CIFS_I(netfile->dentry->d_inode);
 474
 475                                 cifs_set_oplock_level(pCifsInode,
 476                                         pSMB->OplockLevel ? OPLOCK_READ : 0);
 477                                 queue_work(cifsiod_wq,
 478                                            &netfile->oplock_break);
 479                                 netfile->oplock_break_cancelled = false;
 480
 481                                 spin_unlock(&cifs_file_list_lock);
 482                                 spin_unlock(&cifs_tcp_ses_lock);
 483                                 return true;
 484                         }
 485                         spin_unlock(&cifs_file_list_lock);
 486                         spin_unlock(&cifs_tcp_ses_lock);
 487                         cFYI(1, "No matching file for oplock break");
 488                         return true;
 489                 }
 490         }
 491         spin_unlock(&cifs_tcp_ses_lock);
 492         cFYI(1, "Can not process oplock break for non-existent connection");
 493         return true;
 494 }
 495
 496 void
 497 dump_smb(void *buf, int smb_buf_length)
 498 {
 499         int i, j;
 500         char debug_line[17];
 501         unsigned char *buffer = buf;
 502
 503         if (traceSMB == 0)
 504                 return;
 505
 506         for (i = 0, j = 0; i < smb_buf_length; i++, j++) {
 507                 if (i % 8 == 0) {
 508                         /* have reached the beginning of line */
 509                         printk(KERN_DEBUG "| ");
 510                         j = 0;
 511                 }
 512                 printk("%0#4x ", buffer[i]);
 513                 debug_line[2 * j] = ' ';
 514                 if (isprint(buffer[i]))
 515                         debug_line[1 + (2 * j)] = buffer[i];
 516                 else
 517                         debug_line[1 + (2 * j)] = '_';
 518
 519                 if (i % 8 == 7) {
 520                         /* reached end of line, time to print ascii */
 521                         debug_line[16] = 0;
 522                         printk(" | %s\n", debug_line);
 523                 }
 524         }
 525         for (; j < 8; j++) {
 526                 printk("     ");
 527                 debug_line[2 * j] = ' ';
 528                 debug_line[1 + (2 * j)] = ' ';
 529         }
 530         printk(" | %s\n", debug_line);
 531         return;
 532 }
 533
 534 void
 535 cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 536 {
 537         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 538                 cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 539                 cERROR(1, "Autodisabling the use of server inode numbers on "
 540                            "%s. This server doesn't seem to support them "
 541                            "properly. Hardlinks will not be recognized on this "
 542                            "mount. Consider mounting with the \"noserverino\" "
 543                            "option to silence this message.",
 544                            cifs_sb_master_tcon(cifs_sb)->treeName);
 545         }
 546 }
 547
 548 void cifs_set_oplock_level(struct cifsInodeInfo *cinode, __u32 oplock)
 549 {
 550         oplock &= 0xF;
 551
 552         if (oplock == OPLOCK_EXCLUSIVE) {
 553                 cinode->clientCanCacheAll = true;
 554                 cinode->clientCanCacheRead = true;
 555                 cFYI(1, "Exclusive Oplock granted on inode %p",
 556                      &cinode->vfs_inode);
 557         } else if (oplock == OPLOCK_READ) {
 558                 cinode->clientCanCacheAll = false;
 559                 cinode->clientCanCacheRead = true;
 560                 cFYI(1, "Level II Oplock granted on inode %p",
 561                     &cinode->vfs_inode);
 562         } else {
 563                 cinode->clientCanCacheAll = false;
 564                 cinode->clientCanCacheRead = false;
 565         }
 566 }
 567
 568 bool
 569 backup_cred(struct cifs_sb_info *cifs_sb)
 570 {
 571         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPUID) {
 572                 if (cifs_sb->mnt_backupuid == current_fsuid())
 573                         return true;
 574         }
 575         if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_BACKUPGID) {
 576                 if (in_group_p(cifs_sb->mnt_backupgid))
 577                         return true;
 578         }
 579
 580         return false;
 581 }