1 // SPDX-License-Identifier: CDDL-1.0
2 /*
3 * CDDL HEADER START
4 *
5 * The contents of this file are subject to the terms of the
6 * Common Development and Distribution License (the "License").
7 * You may not use this file except in compliance with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or https://opensource.org/licenses/CDDL-1.0.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26 /*
27 * Copyright (c) 2013, 2016 by Delphix. All rights reserved.
28 */
29
30 /*
31 * Common name validation routines for ZFS. These routines are shared by the
32 * userland code as well as the ioctl() layer to ensure that we don't
33 * inadvertently expose a hole through direct ioctl()s that never gets tested.
34 * In userland, however, we want significantly more information about _why_ the
35 * name is invalid. In the kernel, we only care whether it's valid or not.
36 * Each routine therefore takes a 'namecheck_err_t' which describes exactly why
37 * the name failed to validate.
38 */
39
40 #if !defined(_KERNEL)
41 #include <string.h>
42 #endif
43
44 #include <sys/dsl_dir.h>
45 #include <sys/param.h>
46 #include <sys/nvpair.h>
47 #include "zfs_namecheck.h"
48 #include "zfs_deleg.h"
49
50 /*
51 * Deeply nested datasets can overflow the stack, so we put a limit
52 * in the amount of nesting a path can have. zfs_max_dataset_nesting
53 * can be tuned temporarily to fix existing datasets that exceed our
54 * predefined limit.
55 */
56 int zfs_max_dataset_nesting = 50;
57
58 static int
valid_char(char c)59 valid_char(char c)
60 {
61 return ((c >= 'a' && c <= 'z') ||
62 (c >= 'A' && c <= 'Z') ||
63 (c >= '0' && c <= '9') ||
64 c == '-' || c == '_' || c == '.' || c == ':' || c == ' ');
65 }
66
67 /*
68 * Looks at a path and returns its level of nesting (depth).
69 */
70 int
get_dataset_depth(const char * path)71 get_dataset_depth(const char *path)
72 {
73 const char *loc = path;
74 int nesting = 0;
75
76 /*
77 * Keep track of nesting until you hit the end of the
78 * path or found the snapshot/bookmark separator.
79 */
80 for (int i = 0; loc[i] != '\0' &&
81 loc[i] != '@' &&
82 loc[i] != '#'; i++) {
83 if (loc[i] == '/')
84 nesting++;
85 }
86
87 return (nesting);
88 }
89
90 /*
91 * Snapshot names must be made up of alphanumeric characters plus the following
92 * characters:
93 *
94 * [-_.: ]
95 *
96 * Returns 0 on success, -1 on error.
97 */
98 int
zfs_component_namecheck(const char * path,namecheck_err_t * why,char * what)99 zfs_component_namecheck(const char *path, namecheck_err_t *why, char *what)
100 {
101 const char *loc;
102
103 if (strlen(path) >= ZFS_MAX_DATASET_NAME_LEN) {
104 if (why)
105 *why = NAME_ERR_TOOLONG;
106 return (-1);
107 }
108
109 if (path[0] == '\0') {
110 if (why)
111 *why = NAME_ERR_EMPTY_COMPONENT;
112 return (-1);
113 }
114
115 for (loc = path; *loc; loc++) {
116 if (!valid_char(*loc)) {
117 if (why) {
118 *why = NAME_ERR_INVALCHAR;
119 *what = *loc;
120 }
121 return (-1);
122 }
123 }
124 return (0);
125 }
126
127
128 /*
129 * Permissions set name must start with the letter '@' followed by the
130 * same character restrictions as snapshot names, except that the name
131 * cannot exceed 64 characters.
132 *
133 * Returns 0 on success, -1 on error.
134 */
135 int
permset_namecheck(const char * path,namecheck_err_t * why,char * what)136 permset_namecheck(const char *path, namecheck_err_t *why, char *what)
137 {
138 if (strlen(path) >= ZFS_PERMSET_MAXLEN) {
139 if (why)
140 *why = NAME_ERR_TOOLONG;
141 return (-1);
142 }
143
144 if (path[0] != '@') {
145 if (why) {
146 *why = NAME_ERR_NO_AT;
147 *what = path[0];
148 }
149 return (-1);
150 }
151
152 return (zfs_component_namecheck(&path[1], why, what));
153 }
154
155 /*
156 * Dataset paths should not be deeper than zfs_max_dataset_nesting
157 * in terms of nesting.
158 *
159 * Returns 0 on success, -1 on error.
160 */
161 int
dataset_nestcheck(const char * path)162 dataset_nestcheck(const char *path)
163 {
164 return ((get_dataset_depth(path) < zfs_max_dataset_nesting) ? 0 : -1);
165 }
166
167 /*
168 * Entity names must be of the following form:
169 *
170 * [component/]*[component][(@|#)component]?
171 *
172 * Where each component is made up of alphanumeric characters plus the following
173 * characters:
174 *
175 * [-_.: %]
176 *
177 * We allow '%' here as we use that character internally to create unique
178 * names for temporary clones (for online recv).
179 *
180 * Returns 0 on success, -1 on error.
181 */
182 int
entity_namecheck(const char * path,namecheck_err_t * why,char * what)183 entity_namecheck(const char *path, namecheck_err_t *why, char *what)
184 {
185 const char *end;
186
187 EQUIV(why == NULL, what == NULL);
188
189 /*
190 * Make sure the name is not too long.
191 */
192 if (strlen(path) >= ZFS_MAX_DATASET_NAME_LEN) {
193 if (why)
194 *why = NAME_ERR_TOOLONG;
195 return (-1);
196 }
197
198 /* Explicitly check for a leading slash. */
199 if (path[0] == '/') {
200 if (why)
201 *why = NAME_ERR_LEADING_SLASH;
202 return (-1);
203 }
204
205 if (path[0] == '\0') {
206 if (why)
207 *why = NAME_ERR_EMPTY_COMPONENT;
208 return (-1);
209 }
210
211 const char *start = path;
212 boolean_t found_delim = B_FALSE;
213 for (;;) {
214 /* Find the end of this component */
215 end = start;
216 while (*end != '/' && *end != '@' && *end != '#' &&
217 *end != '\0')
218 end++;
219
220 if (*end == '\0' && end[-1] == '/') {
221 /* trailing slashes are not allowed */
222 if (why)
223 *why = NAME_ERR_TRAILING_SLASH;
224 return (-1);
225 }
226
227 /* Validate the contents of this component */
228 for (const char *loc = start; loc != end; loc++) {
229 if (!valid_char(*loc) && *loc != '%') {
230 if (why) {
231 *why = NAME_ERR_INVALCHAR;
232 *what = *loc;
233 }
234 return (-1);
235 }
236 }
237
238 if (*end == '\0' || *end == '/') {
239 int component_length = end - start;
240 /* Validate the contents of this component is not '.' */
241 if (component_length == 1) {
242 if (start[0] == '.') {
243 if (why)
244 *why = NAME_ERR_SELF_REF;
245 return (-1);
246 }
247 }
248
249 /* Validate the content of this component is not '..' */
250 if (component_length == 2) {
251 if (start[0] == '.' && start[1] == '.') {
252 if (why)
253 *why = NAME_ERR_PARENT_REF;
254 return (-1);
255 }
256 }
257 }
258
259 /* Snapshot or bookmark delimiter found */
260 if (*end == '@' || *end == '#') {
261 /* Multiple delimiters are not allowed */
262 if (found_delim != 0) {
263 if (why)
264 *why = NAME_ERR_MULTIPLE_DELIMITERS;
265 return (-1);
266 }
267
268 found_delim = B_TRUE;
269 }
270
271 /* Zero-length components are not allowed */
272 if (start == end) {
273 if (why)
274 *why = NAME_ERR_EMPTY_COMPONENT;
275 return (-1);
276 }
277
278 /* If we've reached the end of the string, we're OK */
279 if (*end == '\0')
280 return (0);
281
282 /*
283 * If there is a '/' in a snapshot or bookmark name
284 * then report an error
285 */
286 if (*end == '/' && found_delim != 0) {
287 if (why)
288 *why = NAME_ERR_TRAILING_SLASH;
289 return (-1);
290 }
291
292 /* Update to the next component */
293 start = end + 1;
294 }
295 }
296
297 /*
298 * Dataset is any entity, except bookmark
299 */
300 int
dataset_namecheck(const char * path,namecheck_err_t * why,char * what)301 dataset_namecheck(const char *path, namecheck_err_t *why, char *what)
302 {
303 int ret = entity_namecheck(path, why, what);
304
305 if (ret == 0 && strchr(path, '#') != NULL) {
306 if (why != NULL) {
307 *why = NAME_ERR_INVALCHAR;
308 *what = '#';
309 }
310 return (-1);
311 }
312
313 return (ret);
314 }
315
316 /*
317 * Assert path is a valid bookmark name
318 */
319 int
bookmark_namecheck(const char * path,namecheck_err_t * why,char * what)320 bookmark_namecheck(const char *path, namecheck_err_t *why, char *what)
321 {
322 int ret = entity_namecheck(path, why, what);
323
324 if (ret == 0 && strchr(path, '#') == NULL) {
325 if (why != NULL) {
326 *why = NAME_ERR_NO_POUND;
327 *what = '#';
328 }
329 return (-1);
330 }
331
332 return (ret);
333 }
334
335 /*
336 * Assert path is a valid snapshot name
337 */
338 int
snapshot_namecheck(const char * path,namecheck_err_t * why,char * what)339 snapshot_namecheck(const char *path, namecheck_err_t *why, char *what)
340 {
341 int ret = entity_namecheck(path, why, what);
342
343 if (ret == 0 && strchr(path, '@') == NULL) {
344 if (why != NULL) {
345 *why = NAME_ERR_NO_AT;
346 *what = '@';
347 }
348 return (-1);
349 }
350
351 return (ret);
352 }
353
354 /*
355 * mountpoint names must be of the following form:
356 *
357 * /[component][/]*[component][/]
358 *
359 * Returns 0 on success, -1 on error.
360 */
361 int
mountpoint_namecheck(const char * path,namecheck_err_t * why)362 mountpoint_namecheck(const char *path, namecheck_err_t *why)
363 {
364 const char *start, *end;
365
366 /*
367 * Make sure none of the mountpoint component names are too long.
368 * If a component name is too long then the mkdir of the mountpoint
369 * will fail but then the mountpoint property will be set to a value
370 * that can never be mounted. Better to fail before setting the prop.
371 * Extra slashes are OK, they will be tossed by the mountpoint mkdir.
372 */
373
374 if (path == NULL || *path != '/') {
375 if (why)
376 *why = NAME_ERR_LEADING_SLASH;
377 return (-1);
378 }
379
380 /* Skip leading slash */
381 start = &path[1];
382 do {
383 end = start;
384 while (*end != '/' && *end != '\0')
385 end++;
386
387 if (end - start >= ZFS_MAX_DATASET_NAME_LEN) {
388 if (why)
389 *why = NAME_ERR_TOOLONG;
390 return (-1);
391 }
392 start = end + 1;
393
394 } while (*end != '\0');
395
396 return (0);
397 }
398
399 /*
400 * For pool names, we have the same set of valid characters as described in
401 * dataset names, with the additional restriction that the pool name must begin
402 * with a letter. The pool names 'raidz' and 'mirror' are also reserved names
403 * that cannot be used.
404 *
405 * Returns 0 on success, -1 on error.
406 */
407 int
pool_namecheck(const char * pool,namecheck_err_t * why,char * what)408 pool_namecheck(const char *pool, namecheck_err_t *why, char *what)
409 {
410 const char *c;
411
412 /*
413 * Make sure the name is not too long.
414 * If we're creating a pool with version >= SPA_VERSION_DSL_SCRUB (v11)
415 * we need to account for additional space needed by the origin ds which
416 * will also be snapshotted: "poolname"+"/"+"$ORIGIN"+"@"+"$ORIGIN".
417 * Play it safe and enforce this limit even if the pool version is < 11
418 * so it can be upgraded without issues.
419 */
420 if (strlen(pool) >= (ZFS_MAX_DATASET_NAME_LEN - 2 -
421 strlen(ORIGIN_DIR_NAME) * 2)) {
422 if (why)
423 *why = NAME_ERR_TOOLONG;
424 return (-1);
425 }
426
427 c = pool;
428 while (*c != '\0') {
429 if (!valid_char(*c)) {
430 if (why) {
431 *why = NAME_ERR_INVALCHAR;
432 *what = *c;
433 }
434 return (-1);
435 }
436 c++;
437 }
438
439 if (!(*pool >= 'a' && *pool <= 'z') &&
440 !(*pool >= 'A' && *pool <= 'Z')) {
441 if (why)
442 *why = NAME_ERR_NOLETTER;
443 return (-1);
444 }
445
446 if (strcmp(pool, "mirror") == 0 ||
447 strcmp(pool, "raidz") == 0 ||
448 strcmp(pool, "draid") == 0) {
449 if (why)
450 *why = NAME_ERR_RESERVED;
451 return (-1);
452 }
453
454 return (0);
455 }
456
457 EXPORT_SYMBOL(entity_namecheck);
458 EXPORT_SYMBOL(pool_namecheck);
459 EXPORT_SYMBOL(dataset_namecheck);
460 EXPORT_SYMBOL(bookmark_namecheck);
461 EXPORT_SYMBOL(snapshot_namecheck);
462 EXPORT_SYMBOL(zfs_component_namecheck);
463 EXPORT_SYMBOL(dataset_nestcheck);
464 EXPORT_SYMBOL(get_dataset_depth);
465 EXPORT_SYMBOL(zfs_max_dataset_nesting);
466
467 ZFS_MODULE_PARAM(zfs, zfs_, max_dataset_nesting, INT, ZMOD_RW,
468 "Limit to the amount of nesting a path can have. Defaults to 50.");
469