module/zcommon/zfs_namecheck.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or https://opensource.org/licenses/CDDL-1.0.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25 /*
  26  * Copyright (c) 2013, 2016 by Delphix. All rights reserved.
  27  */
  28
  29 /*
  30  * Common name validation routines for ZFS.  These routines are shared by the
  31  * userland code as well as the ioctl() layer to ensure that we don't
  32  * inadvertently expose a hole through direct ioctl()s that never gets tested.
  33  * In userland, however, we want significantly more information about _why_ the
  34  * name is invalid.  In the kernel, we only care whether it's valid or not.
  35  * Each routine therefore takes a 'namecheck_err_t' which describes exactly why
  36  * the name failed to validate.
  37  */
  38
  39 #if !defined(_KERNEL)
  40 #include <string.h>
  41 #endif
  42
  43 #include <sys/dsl_dir.h>
  44 #include <sys/param.h>
  45 #include <sys/nvpair.h>
  46 #include "zfs_namecheck.h"
  47 #include "zfs_deleg.h"
  48
  49 /*
  50  * Deeply nested datasets can overflow the stack, so we put a limit
  51  * in the amount of nesting a path can have. zfs_max_dataset_nesting
  52  * can be tuned temporarily to fix existing datasets that exceed our
  53  * predefined limit.
  54  */
  55 int zfs_max_dataset_nesting = 50;
  56
  57 static int
  58 valid_char(char c)
  59 {
  60         return ((c >= 'a' && c <= 'z') ||
  61             (c >= 'A' && c <= 'Z') ||
  62             (c >= '0' && c <= '9') ||
  63             c == '-' || c == '_' || c == '.' || c == ':' || c == ' ');
  64 }
  65
  66 /*
  67  * Looks at a path and returns its level of nesting (depth).
  68  */
  69 int
  70 get_dataset_depth(const char *path)
  71 {
  72         const char *loc = path;
  73         int nesting = 0;
  74
  75         /*
  76          * Keep track of nesting until you hit the end of the
  77          * path or found the snapshot/bookmark separator.
  78          */
  79         for (int i = 0; loc[i] != '\0' &&
  80             loc[i] != '@' &&
  81             loc[i] != '#'; i++) {
  82                 if (loc[i] == '/')
  83                         nesting++;
  84         }
  85
  86         return (nesting);
  87 }
  88
  89 /*
  90  * Snapshot names must be made up of alphanumeric characters plus the following
  91  * characters:
  92  *
  93  *      [-_.: ]
  94  *
  95  * Returns 0 on success, -1 on error.
  96  */
  97 int
  98 zfs_component_namecheck(const char *path, namecheck_err_t *why, char *what)
  99 {
 100         const char *loc;
 101
 102         if (strlen(path) >= ZFS_MAX_DATASET_NAME_LEN) {
 103                 if (why)
 104                         *why = NAME_ERR_TOOLONG;
 105                 return (-1);
 106         }
 107
 108         if (path[0] == '\0') {
 109                 if (why)
 110                         *why = NAME_ERR_EMPTY_COMPONENT;
 111                 return (-1);
 112         }
 113
 114         for (loc = path; *loc; loc++) {
 115                 if (!valid_char(*loc)) {
 116                         if (why) {
 117                                 *why = NAME_ERR_INVALCHAR;
 118                                 *what = *loc;
 119                         }
 120                         return (-1);
 121                 }
 122         }
 123         return (0);
 124 }
 125
 126
 127 /*
 128  * Permissions set name must start with the letter '@' followed by the
 129  * same character restrictions as snapshot names, except that the name
 130  * cannot exceed 64 characters.
 131  *
 132  * Returns 0 on success, -1 on error.
 133  */
 134 int
 135 permset_namecheck(const char *path, namecheck_err_t *why, char *what)
 136 {
 137         if (strlen(path) >= ZFS_PERMSET_MAXLEN) {
 138                 if (why)
 139                         *why = NAME_ERR_TOOLONG;
 140                 return (-1);
 141         }
 142
 143         if (path[0] != '@') {
 144                 if (why) {
 145                         *why = NAME_ERR_NO_AT;
 146                         *what = path[0];
 147                 }
 148                 return (-1);
 149         }
 150
 151         return (zfs_component_namecheck(&path[1], why, what));
 152 }
 153
 154 /*
 155  * Dataset paths should not be deeper than zfs_max_dataset_nesting
 156  * in terms of nesting.
 157  *
 158  * Returns 0 on success, -1 on error.
 159  */
 160 int
 161 dataset_nestcheck(const char *path)
 162 {
 163         return ((get_dataset_depth(path) < zfs_max_dataset_nesting) ? 0 : -1);
 164 }
 165
 166 /*
 167  * Entity names must be of the following form:
 168  *
 169  *      [component/]*[component][(@|#)component]?
 170  *
 171  * Where each component is made up of alphanumeric characters plus the following
 172  * characters:
 173  *
 174  *      [-_.: %]
 175  *
 176  * We allow '%' here as we use that character internally to create unique
 177  * names for temporary clones (for online recv).
 178  *
 179  * Returns 0 on success, -1 on error.
 180  */
 181 int
 182 entity_namecheck(const char *path, namecheck_err_t *why, char *what)
 183 {
 184         const char *end;
 185
 186         EQUIV(why == NULL, what == NULL);
 187
 188         /*
 189          * Make sure the name is not too long.
 190          */
 191         if (strlen(path) >= ZFS_MAX_DATASET_NAME_LEN) {
 192                 if (why)
 193                         *why = NAME_ERR_TOOLONG;
 194                 return (-1);
 195         }
 196
 197         /* Explicitly check for a leading slash.  */
 198         if (path[0] == '/') {
 199                 if (why)
 200                         *why = NAME_ERR_LEADING_SLASH;
 201                 return (-1);
 202         }
 203
 204         if (path[0] == '\0') {
 205                 if (why)
 206                         *why = NAME_ERR_EMPTY_COMPONENT;
 207                 return (-1);
 208         }
 209
 210         const char *start = path;
 211         boolean_t found_delim = B_FALSE;
 212         for (;;) {
 213                 /* Find the end of this component */
 214                 end = start;
 215                 while (*end != '/' && *end != '@' && *end != '#' &&
 216                     *end != '\0')
 217                         end++;
 218
 219                 if (*end == '\0' && end[-1] == '/') {
 220                         /* trailing slashes are not allowed */
 221                         if (why)
 222                                 *why = NAME_ERR_TRAILING_SLASH;
 223                         return (-1);
 224                 }
 225
 226                 /* Validate the contents of this component */
 227                 for (const char *loc = start; loc != end; loc++) {
 228                         if (!valid_char(*loc) && *loc != '%') {
 229                                 if (why) {
 230                                         *why = NAME_ERR_INVALCHAR;
 231                                         *what = *loc;
 232                                 }
 233                                 return (-1);
 234                         }
 235                 }
 236
 237                 if (*end == '\0' || *end == '/') {
 238                         int component_length = end - start;
 239                         /* Validate the contents of this component is not '.' */
 240                         if (component_length == 1) {
 241                                 if (start[0] == '.') {
 242                                         if (why)
 243                                                 *why = NAME_ERR_SELF_REF;
 244                                         return (-1);
 245                                 }
 246                         }
 247
 248                         /* Validate the content of this component is not '..' */
 249                         if (component_length == 2) {
 250                                 if (start[0] == '.' && start[1] == '.') {
 251                                         if (why)
 252                                                 *why = NAME_ERR_PARENT_REF;
 253                                         return (-1);
 254                                 }
 255                         }
 256                 }
 257
 258                 /* Snapshot or bookmark delimiter found */
 259                 if (*end == '@' || *end == '#') {
 260                         /* Multiple delimiters are not allowed */
 261                         if (found_delim != 0) {
 262                                 if (why)
 263                                         *why = NAME_ERR_MULTIPLE_DELIMITERS;
 264                                 return (-1);
 265                         }
 266
 267                         found_delim = B_TRUE;
 268                 }
 269
 270                 /* Zero-length components are not allowed */
 271                 if (start == end) {
 272                         if (why)
 273                                 *why = NAME_ERR_EMPTY_COMPONENT;
 274                         return (-1);
 275                 }
 276
 277                 /* If we've reached the end of the string, we're OK */
 278                 if (*end == '\0')
 279                         return (0);
 280
 281                 /*
 282                  * If there is a '/' in a snapshot or bookmark name
 283                  * then report an error
 284                  */
 285                 if (*end == '/' && found_delim != 0) {
 286                         if (why)
 287                                 *why = NAME_ERR_TRAILING_SLASH;
 288                         return (-1);
 289                 }
 290
 291                 /* Update to the next component */
 292                 start = end + 1;
 293         }
 294 }
 295
 296 /*
 297  * Dataset is any entity, except bookmark
 298  */
 299 int
 300 dataset_namecheck(const char *path, namecheck_err_t *why, char *what)
 301 {
 302         int ret = entity_namecheck(path, why, what);
 303
 304         if (ret == 0 && strchr(path, '#') != NULL) {
 305                 if (why != NULL) {
 306                         *why = NAME_ERR_INVALCHAR;
 307                         *what = '#';
 308                 }
 309                 return (-1);
 310         }
 311
 312         return (ret);
 313 }
 314
 315 /*
 316  * Assert path is a valid bookmark name
 317  */
 318 int
 319 bookmark_namecheck(const char *path, namecheck_err_t *why, char *what)
 320 {
 321         int ret = entity_namecheck(path, why, what);
 322
 323         if (ret == 0 && strchr(path, '#') == NULL) {
 324                 if (why != NULL) {
 325                         *why = NAME_ERR_NO_POUND;
 326                         *what = '#';
 327                 }
 328                 return (-1);
 329         }
 330
 331         return (ret);
 332 }
 333
 334 /*
 335  * Assert path is a valid snapshot name
 336  */
 337 int
 338 snapshot_namecheck(const char *path, namecheck_err_t *why, char *what)
 339 {
 340         int ret = entity_namecheck(path, why, what);
 341
 342         if (ret == 0 && strchr(path, '@') == NULL) {
 343                 if (why != NULL) {
 344                         *why = NAME_ERR_NO_AT;
 345                         *what = '@';
 346                 }
 347                 return (-1);
 348         }
 349
 350         return (ret);
 351 }
 352
 353 /*
 354  * mountpoint names must be of the following form:
 355  *
 356  *      /[component][/]*[component][/]
 357  *
 358  * Returns 0 on success, -1 on error.
 359  */
 360 int
 361 mountpoint_namecheck(const char *path, namecheck_err_t *why)
 362 {
 363         const char *start, *end;
 364
 365         /*
 366          * Make sure none of the mountpoint component names are too long.
 367          * If a component name is too long then the mkdir of the mountpoint
 368          * will fail but then the mountpoint property will be set to a value
 369          * that can never be mounted.  Better to fail before setting the prop.
 370          * Extra slashes are OK, they will be tossed by the mountpoint mkdir.
 371          */
 372
 373         if (path == NULL || *path != '/') {
 374                 if (why)
 375                         *why = NAME_ERR_LEADING_SLASH;
 376                 return (-1);
 377         }
 378
 379         /* Skip leading slash  */
 380         start = &path[1];
 381         do {
 382                 end = start;
 383                 while (*end != '/' && *end != '\0')
 384                         end++;
 385
 386                 if (end - start >= ZFS_MAX_DATASET_NAME_LEN) {
 387                         if (why)
 388                                 *why = NAME_ERR_TOOLONG;
 389                         return (-1);
 390                 }
 391                 start = end + 1;
 392
 393         } while (*end != '\0');
 394
 395         return (0);
 396 }
 397
 398 /*
 399  * For pool names, we have the same set of valid characters as described in
 400  * dataset names, with the additional restriction that the pool name must begin
 401  * with a letter.  The pool names 'raidz' and 'mirror' are also reserved names
 402  * that cannot be used.
 403  *
 404  * Returns 0 on success, -1 on error.
 405  */
 406 int
 407 pool_namecheck(const char *pool, namecheck_err_t *why, char *what)
 408 {
 409         const char *c;
 410
 411         /*
 412          * Make sure the name is not too long.
 413          * If we're creating a pool with version >= SPA_VERSION_DSL_SCRUB (v11)
 414          * we need to account for additional space needed by the origin ds which
 415          * will also be snapshotted: "poolname"+"/"+"$ORIGIN"+"@"+"$ORIGIN".
 416          * Play it safe and enforce this limit even if the pool version is < 11
 417          * so it can be upgraded without issues.
 418          */
 419         if (strlen(pool) >= (ZFS_MAX_DATASET_NAME_LEN - 2 -
 420             strlen(ORIGIN_DIR_NAME) * 2)) {
 421                 if (why)
 422                         *why = NAME_ERR_TOOLONG;
 423                 return (-1);
 424         }
 425
 426         c = pool;
 427         while (*c != '\0') {
 428                 if (!valid_char(*c)) {
 429                         if (why) {
 430                                 *why = NAME_ERR_INVALCHAR;
 431                                 *what = *c;
 432                         }
 433                         return (-1);
 434                 }
 435                 c++;
 436         }
 437
 438         if (!(*pool >= 'a' && *pool <= 'z') &&
 439             !(*pool >= 'A' && *pool <= 'Z')) {
 440                 if (why)
 441                         *why = NAME_ERR_NOLETTER;
 442                 return (-1);
 443         }
 444
 445         if (strcmp(pool, "mirror") == 0 ||
 446             strcmp(pool, "raidz") == 0 ||
 447             strcmp(pool, "draid") == 0) {
 448                 if (why)
 449                         *why = NAME_ERR_RESERVED;
 450                 return (-1);
 451         }
 452
 453         return (0);
 454 }
 455
 456 EXPORT_SYMBOL(entity_namecheck);
 457 EXPORT_SYMBOL(pool_namecheck);
 458 EXPORT_SYMBOL(dataset_namecheck);
 459 EXPORT_SYMBOL(bookmark_namecheck);
 460 EXPORT_SYMBOL(snapshot_namecheck);
 461 EXPORT_SYMBOL(zfs_component_namecheck);
 462 EXPORT_SYMBOL(dataset_nestcheck);
 463 EXPORT_SYMBOL(get_dataset_depth);
 464 EXPORT_SYMBOL(zfs_max_dataset_nesting);
 465
 466 ZFS_MODULE_PARAM(zfs, zfs_, max_dataset_nesting, INT, ZMOD_RW,
 467         "Limit to the amount of nesting a path can have. Defaults to 50.");