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."); 468