source3/modules/vfs_fileid.c

   1 /*
   2  * VFS module to alter the algorithm to calculate
   3  * the struct file_id used as key for the share mode
   4  * and byte range locking db's.
   5  *
   6  * Copyright (C) 2007, Stefan Metzmacher
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 3 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 #include "includes.h"
  23 #include "smbd/smbd.h"
  24 #include "system/filesys.h"
  25
  26 static int vfs_fileid_debug_level = DBGC_VFS;
  27
  28 #undef DBGC_CLASS
  29 #define DBGC_CLASS vfs_fileid_debug_level
  30
  31 struct fileid_mount_entry {
  32         SMB_DEV_T device;
  33         const char *mnt_fsname;
  34         fsid_t fsid;
  35         uint64_t devid;
  36 };
  37
  38 struct fileid_handle_data {
  39         uint64_t (*device_mapping_fn)(struct fileid_handle_data *data,
  40                                       const SMB_STRUCT_STAT *sbuf);
  41         uint64_t (*extid_mapping_fn)(struct fileid_handle_data *data,
  42                                       const SMB_STRUCT_STAT *sbuf);
  43         char **fstype_deny_list;
  44         char **fstype_allow_list;
  45         char **mntdir_deny_list;
  46         char **mntdir_allow_list;
  47         unsigned num_mount_entries;
  48         struct fileid_mount_entry *mount_entries;
  49         ino_t nolockinode;
  50 };
  51
  52 /* check if a mount entry is allowed based on fstype and mount directory */
  53 static bool fileid_mount_entry_allowed(struct fileid_handle_data *data,
  54                                        struct mntent *m)
  55 {
  56         int i;
  57         char **fstype_deny = data->fstype_deny_list;
  58         char **fstype_allow = data->fstype_allow_list;
  59         char **mntdir_deny = data->mntdir_deny_list;
  60         char **mntdir_allow = data->mntdir_allow_list;
  61
  62         if (fstype_deny != NULL) {
  63                 for (i = 0; fstype_deny[i] != NULL; i++) {
  64                         if (strcmp(m->mnt_type, fstype_deny[i]) == 0) {
  65                                 return false;
  66                         }
  67                 }
  68         }
  69         if (fstype_allow != NULL) {
  70                 for (i = 0; fstype_allow[i] != NULL; i++) {
  71                         if (strcmp(m->mnt_type, fstype_allow[i]) == 0) {
  72                                 break;
  73                         }
  74                 }
  75                 if (fstype_allow[i] == NULL) {
  76                         return false;
  77                 }
  78         }
  79         if (mntdir_deny != NULL) {
  80                 for (i=0; mntdir_deny[i] != NULL; i++) {
  81                         if (strcmp(m->mnt_dir, mntdir_deny[i]) == 0) {
  82                                 return false;
  83                         }
  84                 }
  85         }
  86         if (mntdir_allow != NULL) {
  87                 for (i=0; mntdir_allow[i] != NULL; i++) {
  88                         if (strcmp(m->mnt_dir, mntdir_allow[i]) == 0) {
  89                                 break;
  90                         }
  91                 }
  92                 if (mntdir_allow[i] == NULL) {
  93                         return false;
  94                 }
  95         }
  96         return true;
  97 }
  98
  99
 100 /* load all the mount entries from the mtab */
 101 static void fileid_load_mount_entries(struct fileid_handle_data *data)
 102 {
 103         FILE *f;
 104         struct mntent *m;
 105
 106         data->num_mount_entries = 0;
 107         TALLOC_FREE(data->mount_entries);
 108
 109         f = setmntent("/etc/mtab", "r");
 110         if (!f) return;
 111
 112         while ((m = getmntent(f))) {
 113                 struct stat st;
 114                 struct statfs sfs;
 115                 struct fileid_mount_entry *cur;
 116                 bool allowed;
 117
 118                 allowed = fileid_mount_entry_allowed(data, m);
 119                 if (!allowed) {
 120                         DBG_DEBUG("skipping mount entry %s\n", m->mnt_dir);
 121                         continue;
 122                 }
 123                 if (stat(m->mnt_dir, &st) != 0) continue;
 124                 if (statfs(m->mnt_dir, &sfs) != 0) continue;
 125
 126                 if (strncmp(m->mnt_fsname, "/dev/", 5) == 0) {
 127                         m->mnt_fsname += 5;
 128                 }
 129
 130                 data->mount_entries = talloc_realloc(data,
 131                                                            data->mount_entries,
 132                                                            struct fileid_mount_entry,
 133                                                            data->num_mount_entries+1);
 134                 if (data->mount_entries == NULL) {
 135                         goto nomem;
 136                 }
 137
 138                 cur = &data->mount_entries[data->num_mount_entries];
 139                 cur->device     = st.st_dev;
 140                 cur->mnt_fsname = talloc_strdup(data->mount_entries,
 141                                                 m->mnt_fsname);
 142                 if (!cur->mnt_fsname) goto nomem;
 143                 cur->fsid       = sfs.f_fsid;
 144                 cur->devid      = (uint64_t)-1;
 145
 146                 data->num_mount_entries++;
 147         }
 148         endmntent(f);
 149         return;
 150
 151 nomem:
 152         if (f) endmntent(f);
 153
 154         data->num_mount_entries = 0;
 155         TALLOC_FREE(data->mount_entries);
 156
 157         return;
 158 }
 159
 160 /* find a mount entry given a dev_t */
 161 static struct fileid_mount_entry *fileid_find_mount_entry(struct fileid_handle_data *data,
 162                                                           SMB_DEV_T dev)
 163 {
 164         unsigned i;
 165
 166         if (data->num_mount_entries == 0) {
 167                 fileid_load_mount_entries(data);
 168         }
 169         for (i=0;i<data->num_mount_entries;i++) {
 170                 if (data->mount_entries[i].device == dev) {
 171                         return &data->mount_entries[i];
 172                 }
 173         }
 174         /* 2nd pass after reloading */
 175         fileid_load_mount_entries(data);
 176         for (i=0;i<data->num_mount_entries;i++) {
 177                 if (data->mount_entries[i].device == dev) {
 178                         return &data->mount_entries[i];
 179                 }
 180         }
 181         return NULL;
 182 }
 183
 184
 185 /* a 64 bit hash, based on the one in tdb */
 186 static uint64_t fileid_uint64_hash(const uint8_t *s, size_t len)
 187 {
 188         uint64_t value; /* Used to compute the hash value.  */
 189         uint32_t i;     /* Used to cycle through random values. */
 190
 191         /* Set the initial value from the key size. */
 192         for (value = 0x238F13AFLL * len, i=0; i < len; i++)
 193                 value = (value + (((uint64_t)s[i]) << (i*5 % 24)));
 194
 195         return (1103515243LL * value + 12345LL);
 196 }
 197
 198 /* a device mapping using a fsname */
 199 static uint64_t fileid_device_mapping_fsname(struct fileid_handle_data *data,
 200                                              const SMB_STRUCT_STAT *sbuf)
 201 {
 202         struct fileid_mount_entry *m;
 203
 204         m = fileid_find_mount_entry(data, sbuf->st_ex_dev);
 205         if (!m) return sbuf->st_ex_dev;
 206
 207         if (m->devid == (uint64_t)-1) {
 208                 m->devid = fileid_uint64_hash((const uint8_t *)m->mnt_fsname,
 209                                               strlen(m->mnt_fsname));
 210         }
 211
 212         return m->devid;
 213 }
 214
 215 /* a device mapping using a hostname */
 216 static uint64_t fileid_device_mapping_hostname(struct fileid_handle_data *data,
 217                                                const SMB_STRUCT_STAT *sbuf)
 218 {
 219         char hostname[HOST_NAME_MAX+1];
 220         char *devname = NULL;
 221         uint64_t id;
 222         size_t devname_len;
 223         int rc;
 224
 225         rc = gethostname(hostname, HOST_NAME_MAX+1);
 226         if (rc != 0) {
 227                 DBG_ERR("gethostname failed\n");
 228                 return UINT64_MAX;
 229         }
 230
 231         devname = talloc_asprintf(talloc_tos(), "%s%ju",
 232                                   hostname, (uintmax_t)sbuf->st_ex_dev);
 233         if (devname == NULL) {
 234                 DBG_ERR("talloc_asprintf failed\n");
 235                 return UINT64_MAX;
 236         }
 237         devname_len = talloc_array_length(devname) - 1;
 238
 239         id = fileid_uint64_hash((uint8_t *)devname, devname_len);
 240
 241         TALLOC_FREE(devname);
 242
 243         return id;
 244 }
 245
 246 /* a device mapping using a fsname for files and hostname for dirs */
 247 static uint64_t fileid_device_mapping_fsname_nodirs(
 248         struct fileid_handle_data *data,
 249         const SMB_STRUCT_STAT *sbuf)
 250 {
 251         if (S_ISDIR(sbuf->st_ex_mode)) {
 252                 return fileid_device_mapping_hostname(data, sbuf);
 253         }
 254
 255         return fileid_device_mapping_fsname(data, sbuf);
 256 }
 257
 258 /* device mapping functions using a fsid */
 259 static uint64_t fileid_device_mapping_fsid(struct fileid_handle_data *data,
 260                                            const SMB_STRUCT_STAT *sbuf)
 261 {
 262         struct fileid_mount_entry *m;
 263
 264         m = fileid_find_mount_entry(data, sbuf->st_ex_dev);
 265         if (!m) return sbuf->st_ex_dev;
 266
 267         if (m->devid == (uint64_t)-1) {
 268                 if (sizeof(fsid_t) > sizeof(uint64_t)) {
 269                         m->devid = fileid_uint64_hash((uint8_t *)&m->fsid,
 270                                                       sizeof(m->fsid));
 271                 } else {
 272                         union {
 273                                 uint64_t ret;
 274                                 fsid_t fsid;
 275                         } u;
 276                         ZERO_STRUCT(u);
 277                         u.fsid = m->fsid;
 278                         m->devid = u.ret;
 279                 }
 280         }
 281
 282         return m->devid;
 283 }
 284
 285 static uint64_t fileid_extid_mapping_zero(struct fileid_handle_data *data,
 286                                           const SMB_STRUCT_STAT *sbuf)
 287 {
 288         return 0;
 289 }
 290
 291 static uint64_t fileid_extid_mapping_pid(struct fileid_handle_data *data,
 292                                          const SMB_STRUCT_STAT *sbuf)
 293 {
 294         return getpid();
 295 }
 296
 297 static int get_connectpath_ino(struct vfs_handle_struct *handle,
 298                                ino_t *ino)
 299 {
 300         struct smb_filename *fname = NULL;
 301         int ret;
 302
 303         fname = synthetic_smb_fname(talloc_tos(),
 304                                     handle->conn->connectpath,
 305                                     NULL,
 306                                     NULL,
 307                                     0);
 308         if (fname == NULL) {
 309                 DBG_ERR("synthetic_smb_fname failed\n");
 310                 return -1;
 311         }
 312
 313         ret = SMB_VFS_NEXT_STAT(handle, fname);
 314         if (ret != 0) {
 315                 DBG_ERR("stat failed for %s with %s\n",
 316                         handle->conn->connectpath, strerror(errno));
 317                 TALLOC_FREE(fname);
 318                 return -1;
 319         }
 320         *ino = fname->st.st_ex_ino;
 321         TALLOC_FREE(fname);
 322
 323         return 0;
 324 }
 325
 326 static int fileid_connect(struct vfs_handle_struct *handle,
 327                           const char *service, const char *user)
 328 {
 329         struct fileid_handle_data *data;
 330         const char *algorithm;
 331         const char **fstype_deny_list = NULL;
 332         const char **fstype_allow_list = NULL;
 333         const char **mntdir_deny_list = NULL;
 334         const char **mntdir_allow_list = NULL;
 335         int saved_errno;
 336         int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
 337
 338         if (ret < 0) {
 339                 return ret;
 340         }
 341
 342         data = talloc_zero(handle->conn, struct fileid_handle_data);
 343         if (!data) {
 344                 saved_errno = errno;
 345                 SMB_VFS_NEXT_DISCONNECT(handle);
 346                 DEBUG(0, ("talloc_zero() failed\n"));
 347                 errno = saved_errno;
 348                 return -1;
 349         }
 350
 351         data->nolockinode = 0;
 352
 353         /*
 354          * "fileid:mapping" is only here as fallback for old setups
 355          * "fileid:algorithm" is the option new setups should use
 356          */
 357         algorithm = lp_parm_const_string(SNUM(handle->conn),
 358                                          "fileid", "mapping",
 359                                          "fsname");
 360         algorithm = lp_parm_const_string(SNUM(handle->conn),
 361                                          "fileid", "algorithm",
 362                                          algorithm);
 363         if (strcmp("fsname", algorithm) == 0) {
 364                 data->device_mapping_fn = fileid_device_mapping_fsname;
 365                 data->extid_mapping_fn = fileid_extid_mapping_zero;
 366         } else if (strcmp("fsname_nodirs", algorithm) == 0) {
 367                 data->device_mapping_fn = fileid_device_mapping_fsname_nodirs;
 368                 data->extid_mapping_fn = fileid_extid_mapping_zero;
 369         } else if (strcmp("fsid", algorithm) == 0) {
 370                 data->device_mapping_fn = fileid_device_mapping_fsid;
 371                 data->extid_mapping_fn = fileid_extid_mapping_zero;
 372         } else if (strcmp("hostname", algorithm) == 0) {
 373                 data->device_mapping_fn = fileid_device_mapping_hostname;
 374                 data->extid_mapping_fn = fileid_extid_mapping_zero;
 375         } else if (strcmp("fsname_norootdir", algorithm) == 0) {
 376                 data->device_mapping_fn = fileid_device_mapping_fsname;
 377                 data->extid_mapping_fn = fileid_extid_mapping_zero;
 378
 379                 ret = get_connectpath_ino(handle, &data->nolockinode);
 380                 if (ret != 0) {
 381                         saved_errno = errno;
 382                         SMB_VFS_NEXT_DISCONNECT(handle);
 383                         errno = saved_errno;
 384                         return -1;
 385                 }
 386         } else if (strcmp("fsname_norootdir_ext", algorithm) == 0) {
 387                 data->device_mapping_fn = fileid_device_mapping_fsname;
 388                 data->extid_mapping_fn = fileid_extid_mapping_pid;
 389
 390                 ret = get_connectpath_ino(handle, &data->nolockinode);
 391                 if (ret != 0) {
 392                         saved_errno = errno;
 393                         SMB_VFS_NEXT_DISCONNECT(handle);
 394                         errno = saved_errno;
 395                         return -1;
 396                 }
 397         } else {
 398                 SMB_VFS_NEXT_DISCONNECT(handle);
 399                 DEBUG(0,("fileid_connect(): unknown algorithm[%s]\n", algorithm));
 400                 return -1;
 401         }
 402
 403         fstype_deny_list = lp_parm_string_list(SNUM(handle->conn), "fileid",
 404                                                "fstype deny", NULL);
 405         if (fstype_deny_list != NULL) {
 406                 data->fstype_deny_list = str_list_copy(data, fstype_deny_list);
 407                 if (data->fstype_deny_list == NULL) {
 408                         saved_errno = errno;
 409                         DBG_ERR("str_list_copy failed\n");
 410                         SMB_VFS_NEXT_DISCONNECT(handle);
 411                         errno = saved_errno;
 412                         return -1;
 413                 }
 414         }
 415
 416         fstype_allow_list = lp_parm_string_list(SNUM(handle->conn), "fileid",
 417                                                 "fstype allow", NULL);
 418         if (fstype_allow_list != NULL) {
 419                 data->fstype_allow_list = str_list_copy(data, fstype_allow_list);
 420                 if (data->fstype_allow_list == NULL) {
 421                         saved_errno = errno;
 422                         DBG_ERR("str_list_copy failed\n");
 423                         SMB_VFS_NEXT_DISCONNECT(handle);
 424                         errno = saved_errno;
 425                         return -1;
 426                 }
 427         }
 428
 429         mntdir_deny_list = lp_parm_string_list(SNUM(handle->conn), "fileid",
 430                                                "mntdir deny", NULL);
 431         if (mntdir_deny_list != NULL) {
 432                 data->mntdir_deny_list = str_list_copy(data, mntdir_deny_list);
 433                 if (data->mntdir_deny_list == NULL) {
 434                         saved_errno = errno;
 435                         DBG_ERR("str_list_copy failed\n");
 436                         SMB_VFS_NEXT_DISCONNECT(handle);
 437                         errno = saved_errno;
 438                         return -1;
 439                 }
 440         }
 441
 442         mntdir_allow_list = lp_parm_string_list(SNUM(handle->conn), "fileid",
 443                                                 "mntdir allow", NULL);
 444         if (mntdir_allow_list != NULL) {
 445                 data->mntdir_allow_list = str_list_copy(data, mntdir_allow_list);
 446                 if (data->mntdir_allow_list == NULL) {
 447                         saved_errno = errno;
 448                         DBG_ERR("str_list_copy failed\n");
 449                         SMB_VFS_NEXT_DISCONNECT(handle);
 450                         errno = saved_errno;
 451                         return -1;
 452                 }
 453         }
 454
 455         data->nolockinode = lp_parm_ulong(SNUM(handle->conn), "fileid",
 456                                           "nolockinode", data->nolockinode);
 457
 458         SMB_VFS_HANDLE_SET_DATA(handle, data, NULL,
 459                                 struct fileid_handle_data,
 460                                 return -1);
 461
 462         DBG_DEBUG("connect to service[%s] with algorithm[%s] nolockinode %lli\n",
 463                   service, algorithm, (long long) data->nolockinode);
 464
 465         return 0;
 466 }
 467
 468 static void fileid_disconnect(struct vfs_handle_struct *handle)
 469 {
 470         const struct loadparm_substitution *lp_sub =
 471                 loadparm_s3_global_substitution();
 472
 473         DEBUG(10,("fileid_disconnect() connect to service[%s].\n",
 474                   lp_servicename(talloc_tos(), lp_sub, SNUM(handle->conn))));
 475
 476         SMB_VFS_NEXT_DISCONNECT(handle);
 477 }
 478
 479 static struct file_id fileid_file_id_create(struct vfs_handle_struct *handle,
 480                                             const SMB_STRUCT_STAT *sbuf)
 481 {
 482         struct fileid_handle_data *data;
 483         struct file_id id;
 484         uint64_t devid;
 485
 486         ZERO_STRUCT(id);
 487
 488         SMB_VFS_HANDLE_GET_DATA(handle, data,
 489                                 struct fileid_handle_data,
 490                                 return id);
 491
 492         if ((data->nolockinode != 0) &&
 493             (sbuf->st_ex_ino == data->nolockinode)) {
 494                 devid = fileid_device_mapping_hostname(data, sbuf);
 495                 id.extid = data->extid_mapping_fn(data, sbuf);
 496         } else {
 497                 devid = data->device_mapping_fn(data, sbuf);
 498         }
 499
 500         id.inode        = sbuf->st_ex_ino;
 501         id.devid        = devid;
 502
 503         DBG_DEBUG("Returning dev [%jx] inode [%jx] extid [%jx]\n",
 504                   (uintmax_t)id.devid, (uintmax_t)id.inode, (uintmax_t)id.extid);
 505
 506         return id;
 507 }
 508
 509 static struct vfs_fn_pointers vfs_fileid_fns = {
 510         .connect_fn = fileid_connect,
 511         .disconnect_fn = fileid_disconnect,
 512         .file_id_create_fn = fileid_file_id_create
 513 };
 514
 515 static_decl_vfs;
 516 NTSTATUS vfs_fileid_init(TALLOC_CTX *ctx)
 517 {
 518         NTSTATUS ret;
 519
 520         ret = smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "fileid",
 521                                &vfs_fileid_fns);
 522         if (!NT_STATUS_IS_OK(ret)) {
 523                 return ret;
 524         }
 525
 526         vfs_fileid_debug_level = debug_add_class("fileid");
 527         if (vfs_fileid_debug_level == -1) {
 528                 vfs_fileid_debug_level = DBGC_VFS;
 529                 DEBUG(0, ("vfs_fileid: Couldn't register custom debugging class!\n"));
 530         } else {
 531                 DEBUG(10, ("vfs_fileid: Debug class number of 'fileid': %d\n", vfs_fileid_debug_level));
 532         }
 533
 534         return ret;
 535 }