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
valid_char(char c)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
get_dataset_depth(const char * path)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
zfs_component_namecheck(const char * path,namecheck_err_t * why,char * what)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
permset_namecheck(const char * path,namecheck_err_t * why,char * what)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
dataset_nestcheck(const char * path)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
entity_namecheck(const char * path,namecheck_err_t * why,char * what)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
dataset_namecheck(const char * path,namecheck_err_t * why,char * what)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
bookmark_namecheck(const char * path,namecheck_err_t * why,char * what)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
snapshot_namecheck(const char * path,namecheck_err_t * why,char * what)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
mountpoint_namecheck(const char * path,namecheck_err_t * why)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
pool_namecheck(const char * pool,namecheck_err_t * why,char * what)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