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         char **fstype_deny_list;
  42         char **fstype_allow_list;
  43         char **mntdir_deny_list;
  44         char **mntdir_allow_list;
  45         unsigned num_mount_entries;
  46         struct fileid_mount_entry *mount_entries;
  47         ino_t nolockinode;
  48 };
  49
  50 /* check if a mount entry is allowed based on fstype and mount directory */
  51 static bool fileid_mount_entry_allowed(struct fileid_handle_data *data,
  52                                        struct mntent *m)
  53 {
  54         int i;
  55         char **fstype_deny = data->fstype_deny_list;
  56         char **fstype_allow = data->fstype_allow_list;
  57         char **mntdir_deny = data->mntdir_deny_list;
  58         char **mntdir_allow = data->mntdir_allow_list;
  59
  60         if (fstype_deny != NULL) {
  61                 for (i = 0; fstype_deny[i] != NULL; i++) {
  62                         if (strcmp(m->mnt_type, fstype_deny[i]) == 0) {
  63                                 return false;
  64                         }
  65                 }
  66         }
  67         if (fstype_allow != NULL) {
  68                 for (i = 0; fstype_allow[i] != NULL; i++) {
  69                         if (strcmp(m->mnt_type, fstype_allow[i]) == 0) {
  70                                 break;
  71                         }
  72                 }
  73                 if (fstype_allow[i] == NULL) {
  74                         return false;
  75                 }
  76         }
  77         if (mntdir_deny != NULL) {
  78                 for (i=0; mntdir_deny[i] != NULL; i++) {
  79                         if (strcmp(m->mnt_dir, mntdir_deny[i]) == 0) {
  80                                 return false;
  81                         }
  82                 }
  83         }
  84         if (mntdir_allow != NULL) {
  85                 for (i=0; mntdir_allow[i] != NULL; i++) {
  86                         if (strcmp(m->mnt_dir, mntdir_allow[i]) == 0) {
  87                                 break;
  88                         }
  89                 }
  90                 if (mntdir_allow[i] == NULL) {
  91                         return false;
  92                 }
  93         }
  94         return true;
  95 }
  96
  97
  98 /* load all the mount entries from the mtab */
  99 static void fileid_load_mount_entries(struct fileid_handle_data *data)
 100 {
 101         FILE *f;
 102         struct mntent *m;
 103
 104         data->num_mount_entries = 0;
 105         TALLOC_FREE(data->mount_entries);
 106
 107         f = setmntent("/etc/mtab", "r");
 108         if (!f) return;
 109
 110         while ((m = getmntent(f))) {
 111                 struct stat st;
 112                 struct statfs sfs;
 113                 struct fileid_mount_entry *cur;
 114                 bool allowed;
 115
 116                 allowed = fileid_mount_entry_allowed(data, m);
 117                 if (!allowed) {
 118                         DBG_DEBUG("skipping mount entry %s\n", m->mnt_dir);
 119                         continue;
 120                 }
 121                 if (stat(m->mnt_dir, &st) != 0) continue;
 122                 if (statfs(m->mnt_dir, &sfs) != 0) continue;
 123
 124                 if (strncmp(m->mnt_fsname, "/dev/", 5) == 0) {
 125                         m->mnt_fsname += 5;
 126                 }
 127
 128                 data->mount_entries = talloc_realloc(data,
 129                                                            data->mount_entries,
 130                                                            struct fileid_mount_entry,
 131                                                            data->num_mount_entries+1);
 132                 if (data->mount_entries == NULL) {
 133                         goto nomem;
 134                 }
 135
 136                 cur = &data->mount_entries[data->num_mount_entries];
 137                 cur->device     = st.st_dev;
 138                 cur->mnt_fsname = talloc_strdup(data->mount_entries,
 139                                                 m->mnt_fsname);
 140                 if (!cur->mnt_fsname) goto nomem;
 141                 cur->fsid       = sfs.f_fsid;
 142                 cur->devid      = (uint64_t)-1;
 143
 144                 data->num_mount_entries++;
 145         }
 146         endmntent(f);
 147         return;
 148
 149 nomem:
 150         if (f) endmntent(f);
 151
 152         data->num_mount_entries = 0;
 153         TALLOC_FREE(data->mount_entries);
 154
 155         return;
 156 }
 157
 158 /* find a mount entry given a dev_t */
 159 static struct fileid_mount_entry *fileid_find_mount_entry(struct fileid_handle_data *data,
 160                                                           SMB_DEV_T dev)
 161 {
 162         unsigned i;
 163
 164         if (data->num_mount_entries == 0) {
 165                 fileid_load_mount_entries(data);
 166         }
 167         for (i=0;i<data->num_mount_entries;i++) {
 168                 if (data->mount_entries[i].device == dev) {
 169                         return &data->mount_entries[i];
 170                 }
 171         }
 172         /* 2nd pass after reloading */
 173         fileid_load_mount_entries(data);
 174         for (i=0;i<data->num_mount_entries;i++) {
 175                 if (data->mount_entries[i].device == dev) {
 176                         return &data->mount_entries[i];
 177                 }
 178         }
 179         return NULL;
 180 }
 181
 182
 183 /* a 64 bit hash, based on the one in tdb */
 184 static uint64_t fileid_uint64_hash(const uint8_t *s, size_t len)
 185 {
 186         uint64_t value; /* Used to compute the hash value.  */
 187         uint32_t i;     /* Used to cycle through random values. */
 188
 189         /* Set the initial value from the key size. */
 190         for (value = 0x238F13AFLL * len, i=0; i < len; i++)
 191                 value = (value + (((uint64_t)s[i]) << (i*5 % 24)));
 192
 193         return (1103515243LL * value + 12345LL);
 194 }
 195
 196 /* a device mapping using a fsname */
 197 static uint64_t fileid_device_mapping_fsname(struct fileid_handle_data *data,
 198                                              const SMB_STRUCT_STAT *sbuf)
 199 {
 200         struct fileid_mount_entry *m;
 201
 202         m = fileid_find_mount_entry(data, sbuf->st_ex_dev);
 203         if (!m) return sbuf->st_ex_dev;
 204
 205         if (m->devid == (uint64_t)-1) {
 206                 m->devid = fileid_uint64_hash((const uint8_t *)m->mnt_fsname,
 207                                               strlen(m->mnt_fsname));
 208         }
 209
 210         return m->devid;
 211 }
 212
 213 /* a device mapping using a hostname */
 214 static uint64_t fileid_device_mapping_hostname(struct fileid_handle_data *data,
 215                                                const SMB_STRUCT_STAT *sbuf)
 216 {
 217         char hostname[HOST_NAME_MAX+1];
 218         char *devname = NULL;
 219         uint64_t id;
 220         size_t devname_len;
 221         int rc;
 222
 223         rc = gethostname(hostname, HOST_NAME_MAX+1);
 224         if (rc != 0) {
 225                 DBG_ERR("gethostname failed\n");
 226                 return UINT64_MAX;
 227         }
 228
 229         devname = talloc_asprintf(talloc_tos(), "%s%lu",
 230                                   hostname, sbuf->st_ex_dev);
 231         if (devname == NULL) {
 232                 DBG_ERR("talloc_asprintf failed\n");
 233                 return UINT64_MAX;
 234         }
 235         devname_len = talloc_array_length(devname) - 1;
 236         TALLOC_FREE(devname);
 237
 238         id = fileid_uint64_hash((uint8_t *)devname, devname_len);
 239         return id;
 240 }
 241
 242 /* a device mapping using a fsname for files and hostname for dirs */
 243 static uint64_t fileid_device_mapping_fsname_nodirs(
 244         struct fileid_handle_data *data,
 245         const SMB_STRUCT_STAT *sbuf)
 246 {
 247         if (S_ISDIR(sbuf->st_ex_mode)) {
 248                 return fileid_device_mapping_hostname(data, sbuf);
 249         }
 250
 251         return fileid_device_mapping_fsname(data, sbuf);
 252 }
 253
 254 /* device mapping functions using a fsid */
 255 static uint64_t fileid_device_mapping_fsid(struct fileid_handle_data *data,
 256                                            const SMB_STRUCT_STAT *sbuf)
 257 {
 258         struct fileid_mount_entry *m;
 259
 260         m = fileid_find_mount_entry(data, sbuf->st_ex_dev);
 261         if (!m) return sbuf->st_ex_dev;
 262
 263         if (m->devid == (uint64_t)-1) {
 264                 if (sizeof(fsid_t) > sizeof(uint64_t)) {
 265                         m->devid = fileid_uint64_hash((uint8_t *)&m->fsid,
 266                                                       sizeof(m->fsid));
 267                 } else {
 268                         union {
 269                                 uint64_t ret;
 270                                 fsid_t fsid;
 271                         } u;
 272                         ZERO_STRUCT(u);
 273                         u.fsid = m->fsid;
 274                         m->devid = u.ret;
 275                 }
 276         }
 277
 278         return m->devid;
 279 }
 280
 281 static int fileid_connect(struct vfs_handle_struct *handle,
 282                           const char *service, const char *user)
 283 {
 284         struct fileid_handle_data *data;
 285         const char *algorithm;
 286         const char **fstype_deny_list = NULL;
 287         const char **fstype_allow_list = NULL;
 288         const char **mntdir_deny_list = NULL;
 289         const char **mntdir_allow_list = NULL;
 290         int saved_errno;
 291         int ret = SMB_VFS_NEXT_CONNECT(handle, service, user);
 292
 293         if (ret < 0) {
 294                 return ret;
 295         }
 296
 297         data = talloc_zero(handle->conn, struct fileid_handle_data);
 298         if (!data) {
 299                 saved_errno = errno;
 300                 SMB_VFS_NEXT_DISCONNECT(handle);
 301                 DEBUG(0, ("talloc_zero() failed\n"));
 302                 errno = saved_errno;
 303                 return -1;
 304         }
 305
 306         /*
 307          * "fileid:mapping" is only here as fallback for old setups
 308          * "fileid:algorithm" is the option new setups should use
 309          */
 310         algorithm = lp_parm_const_string(SNUM(handle->conn),
 311                                          "fileid", "mapping",
 312                                          "fsname");
 313         algorithm = lp_parm_const_string(SNUM(handle->conn),
 314                                          "fileid", "algorithm",
 315                                          algorithm);
 316         if (strcmp("fsname", algorithm) == 0) {
 317                 data->device_mapping_fn = fileid_device_mapping_fsname;
 318         } else if (strcmp("fsname_nodirs", algorithm) == 0) {
 319                 data->device_mapping_fn = fileid_device_mapping_fsname_nodirs;
 320         } else if (strcmp("fsid", algorithm) == 0) {
 321                 data->device_mapping_fn = fileid_device_mapping_fsid;
 322         } else if (strcmp("hostname", algorithm) == 0) {
 323                 data->device_mapping_fn = fileid_device_mapping_hostname;
 324         } else {
 325                 SMB_VFS_NEXT_DISCONNECT(handle);
 326                 DEBUG(0,("fileid_connect(): unknown algorithm[%s]\n", algorithm));
 327                 return -1;
 328         }
 329
 330         fstype_deny_list = lp_parm_string_list(SNUM(handle->conn), "fileid",
 331                                                "fstype deny", NULL);
 332         if (fstype_deny_list != NULL) {
 333                 data->fstype_deny_list = str_list_copy(data, fstype_deny_list);
 334                 if (data->fstype_deny_list == NULL) {
 335                         saved_errno = errno;
 336                         DBG_ERR("str_list_copy failed\n");
 337                         SMB_VFS_NEXT_DISCONNECT(handle);
 338                         errno = saved_errno;
 339                         return -1;
 340                 }
 341         }
 342
 343         fstype_allow_list = lp_parm_string_list(SNUM(handle->conn), "fileid",
 344                                                 "fstype allow", NULL);
 345         if (fstype_allow_list != NULL) {
 346                 data->fstype_allow_list = str_list_copy(data, fstype_allow_list);
 347                 if (data->fstype_allow_list == NULL) {
 348                         saved_errno = errno;
 349                         DBG_ERR("str_list_copy failed\n");
 350                         SMB_VFS_NEXT_DISCONNECT(handle);
 351                         errno = saved_errno;
 352                         return -1;
 353                 }
 354         }
 355
 356         mntdir_deny_list = lp_parm_string_list(SNUM(handle->conn), "fileid",
 357                                                "mntdir deny", NULL);
 358         if (mntdir_deny_list != NULL) {
 359                 data->mntdir_deny_list = str_list_copy(data, mntdir_deny_list);
 360                 if (data->mntdir_deny_list == NULL) {
 361                         saved_errno = errno;
 362                         DBG_ERR("str_list_copy failed\n");
 363                         SMB_VFS_NEXT_DISCONNECT(handle);
 364                         errno = saved_errno;
 365                         return -1;
 366                 }
 367         }
 368
 369         mntdir_allow_list = lp_parm_string_list(SNUM(handle->conn), "fileid",
 370                                                 "mntdir allow", NULL);
 371         if (mntdir_allow_list != NULL) {
 372                 data->mntdir_allow_list = str_list_copy(data, mntdir_allow_list);
 373                 if (data->mntdir_allow_list == NULL) {
 374                         saved_errno = errno;
 375                         DBG_ERR("str_list_copy failed\n");
 376                         SMB_VFS_NEXT_DISCONNECT(handle);
 377                         errno = saved_errno;
 378                         return -1;
 379                 }
 380         }
 381
 382         data->nolockinode = lp_parm_ulong(SNUM(handle->conn), "fileid",
 383                                           "nolockinode", 0);
 384
 385         SMB_VFS_HANDLE_SET_DATA(handle, data, NULL,
 386                                 struct fileid_handle_data,
 387                                 return -1);
 388
 389         DEBUG(10, ("fileid_connect(): connect to service[%s] with algorithm[%s]\n",
 390                 service, algorithm));
 391
 392         return 0;
 393 }
 394
 395 static void fileid_disconnect(struct vfs_handle_struct *handle)
 396 {
 397         DEBUG(10,("fileid_disconnect() connect to service[%s].\n",
 398                   lp_servicename(talloc_tos(), SNUM(handle->conn))));
 399
 400         SMB_VFS_NEXT_DISCONNECT(handle);
 401 }
 402
 403 static struct file_id fileid_file_id_create(struct vfs_handle_struct *handle,
 404                                             const SMB_STRUCT_STAT *sbuf)
 405 {
 406         struct fileid_handle_data *data;
 407         struct file_id id;
 408         uint64_t devid;
 409
 410         ZERO_STRUCT(id);
 411
 412         SMB_VFS_HANDLE_GET_DATA(handle, data,
 413                                 struct fileid_handle_data,
 414                                 return id);
 415
 416         if ((data->nolockinode != 0) && (id.inode == data->nolockinode)) {
 417                 devid = fileid_device_mapping_hostname(data, sbuf);
 418         } else {
 419                 devid = data->device_mapping_fn(data, sbuf);
 420         }
 421
 422         id.inode        = sbuf->st_ex_ino;
 423         id.devid        = devid;
 424
 425         DBG_DEBUG("Returning dev [%jx] inode [%jx]\n",
 426                   (uintmax_t)id.devid, (uintmax_t)id.inode);
 427
 428         return id;
 429 }
 430
 431 static struct vfs_fn_pointers vfs_fileid_fns = {
 432         .connect_fn = fileid_connect,
 433         .disconnect_fn = fileid_disconnect,
 434         .file_id_create_fn = fileid_file_id_create
 435 };
 436
 437 static_decl_vfs;
 438 NTSTATUS vfs_fileid_init(TALLOC_CTX *ctx)
 439 {
 440         NTSTATUS ret;
 441
 442         ret = smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "fileid",
 443                                &vfs_fileid_fns);
 444         if (!NT_STATUS_IS_OK(ret)) {
 445                 return ret;
 446         }
 447
 448         vfs_fileid_debug_level = debug_add_class("fileid");
 449         if (vfs_fileid_debug_level == -1) {
 450                 vfs_fileid_debug_level = DBGC_VFS;
 451                 DEBUG(0, ("vfs_fileid: Couldn't register custom debugging class!\n"));
 452         } else {
 453                 DEBUG(10, ("vfs_fileid: Debug class number of 'fileid': %d\n", vfs_fileid_debug_level));
 454         }
 455
 456         return ret;
 457 }