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 http://www.opensolaris.org/os/licensing.
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 <sys/systm.h>
41 #else
42 #include <string.h>
43 #endif
44
45 #include <sys/dsl_dir.h>
46 #include <sys/param.h>
47 #include <sys/nvpair.h>
48 #include "zfs_namecheck.h"
49 #include "zfs_deleg.h"
50
51 /*
52 * Deeply nested datasets can overflow the stack, so we put a limit
53 * in the amount of nesting a path can have. zfs_max_dataset_nesting
54 * can be tuned temporarily to fix existing datasets that exceed our
55 * predefined limit.
56 */
57 int zfs_max_dataset_nesting = 50;
58
59 static int
valid_char(char c)60 valid_char(char c)
61 {
62 return ((c >= 'a' && c <= 'z') ||
63 (c >= 'A' && c <= 'Z') ||
64 (c >= '0' && c <= '9') ||
65 c == '-' || c == '_' || c == '.' || c == ':' || c == ' ');
66 }
67
68 /*
69 * Looks at a path and returns its level of nesting (depth).
70 */
71 int
get_dataset_depth(const char * path)72 get_dataset_depth(const char *path)
73 {
74 const char *loc = path;
75 int nesting = 0;
76
77 /*
78 * Keep track of nesting until you hit the end of the
79 * path or found the snapshot/bookmark seperator.
80 */
81 for (int i = 0; loc[i] != '\0' &&
82 loc[i] != '@' &&
83 loc[i] != '#'; i++) {
84 if (loc[i] == '/')
85 nesting++;
86 }
87
88 return (nesting);
89 }
90
91 /*
92 * Snapshot names must be made up of alphanumeric characters plus the following
93 * characters:
94 *
95 * [-_.: ]
96 *
97 * Returns 0 on success, -1 on error.
98 */
99 int
zfs_component_namecheck(const char * path,namecheck_err_t * why,char * what)100 zfs_component_namecheck(const char *path, namecheck_err_t *why, char *what)
101 {
102 const char *loc;
103
104 if (strlen(path) >= ZFS_MAX_DATASET_NAME_LEN) {
105 if (why)
106 *why = NAME_ERR_TOOLONG;
107 return (-1);
108 }
109
110 if (path[0] == '\0') {
111 if (why)
112 *why = NAME_ERR_EMPTY_COMPONENT;
113 return (-1);
114 }
115
116 for (loc = path; *loc; loc++) {
117 if (!valid_char(*loc)) {
118 if (why) {
119 *why = NAME_ERR_INVALCHAR;
120 *what = *loc;
121 }
122 return (-1);
123 }
124 }
125 return (0);
126 }
127
128
129 /*
130 * Permissions set name must start with the letter '@' followed by the
131 * same character restrictions as snapshot names, except that the name
132 * cannot exceed 64 characters.
133 *
134 * Returns 0 on success, -1 on error.
135 */
136 int
permset_namecheck(const char * path,namecheck_err_t * why,char * what)137 permset_namecheck(const char *path, namecheck_err_t *why, char *what)
138 {
139 if (strlen(path) >= ZFS_PERMSET_MAXLEN) {
140 if (why)
141 *why = NAME_ERR_TOOLONG;
142 return (-1);
143 }
144
145 if (path[0] != '@') {
146 if (why) {
147 *why = NAME_ERR_NO_AT;
148 *what = path[0];
149 }
150 return (-1);
151 }
152
153 return (zfs_component_namecheck(&path[1], why, what));
154 }
155
156 /*
157 * Dataset paths should not be deeper than zfs_max_dataset_nesting
158 * in terms of nesting.
159 *
160 * Returns 0 on success, -1 on error.
161 */
162 int
dataset_nestcheck(const char * path)163 dataset_nestcheck(const char *path)
164 {
165 return ((get_dataset_depth(path) < zfs_max_dataset_nesting) ? 0 : -1);
166 }
167
168 /*
169 * Entity names must be of the following form:
170 *
171 * [component/]*[component][(@|#)component]?
172 *
173 * Where each component is made up of alphanumeric characters plus the following
174 * characters:
175 *
176 * [-_.:%]
177 *
178 * We allow '%' here as we use that character internally to create unique
179 * names for temporary clones (for online recv).
180 *
181 * Returns 0 on success, -1 on error.
182 */
183 int
entity_namecheck(const char * path,namecheck_err_t * why,char * what)184 entity_namecheck(const char *path, namecheck_err_t *why, char *what)
185 {
186 const char *end;
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 /* Snapshot or bookmark delimiter found */
238 if (*end == '@' || *end == '#') {
239 /* Multiple delimiters are not allowed */
240 if (found_delim != 0) {
241 if (why)
242 *why = NAME_ERR_MULTIPLE_DELIMITERS;
243 return (-1);
244 }
245
246 found_delim = B_TRUE;
247 }
248
249 /* Zero-length components are not allowed */
250 if (start == end) {
251 if (why)
252 *why = NAME_ERR_EMPTY_COMPONENT;
253 return (-1);
254 }
255
256 /* If we've reached the end of the string, we're OK */
257 if (*end == '\0')
258 return (0);
259
260 /*
261 * If there is a '/' in a snapshot or bookmark name
262 * then report an error
263 */
264 if (*end == '/' && found_delim != 0) {
265 if (why)
266 *why = NAME_ERR_TRAILING_SLASH;
267 return (-1);
268 }
269
270 /* Update to the next component */
271 start = end + 1;
272 }
273 }
274
275 /*
276 * Dataset is any entity, except bookmark
277 */
278 int
dataset_namecheck(const char * path,namecheck_err_t * why,char * what)279 dataset_namecheck(const char *path, namecheck_err_t *why, char *what)
280 {
281 int ret = entity_namecheck(path, why, what);
282
283 if (ret == 0 && strchr(path, '#') != NULL) {
284 if (why != NULL) {
285 *why = NAME_ERR_INVALCHAR;
286 *what = '#';
287 }
288 return (-1);
289 }
290
291 return (ret);
292 }
293
294 /*
295 * mountpoint names must be of the following form:
296 *
297 * /[component][/]*[component][/]
298 *
299 * Returns 0 on success, -1 on error.
300 */
301 int
mountpoint_namecheck(const char * path,namecheck_err_t * why)302 mountpoint_namecheck(const char *path, namecheck_err_t *why)
303 {
304 const char *start, *end;
305
306 /*
307 * Make sure none of the mountpoint component names are too long.
308 * If a component name is too long then the mkdir of the mountpoint
309 * will fail but then the mountpoint property will be set to a value
310 * that can never be mounted. Better to fail before setting the prop.
311 * Extra slashes are OK, they will be tossed by the mountpoint mkdir.
312 */
313
314 if (path == NULL || *path != '/') {
315 if (why)
316 *why = NAME_ERR_LEADING_SLASH;
317 return (-1);
318 }
319
320 /* Skip leading slash */
321 start = &path[1];
322 do {
323 end = start;
324 while (*end != '/' && *end != '\0')
325 end++;
326
327 if (end - start >= ZFS_MAX_DATASET_NAME_LEN) {
328 if (why)
329 *why = NAME_ERR_TOOLONG;
330 return (-1);
331 }
332 start = end + 1;
333
334 } while (*end != '\0');
335
336 return (0);
337 }
338
339 /*
340 * For pool names, we have the same set of valid characters as described in
341 * dataset names, with the additional restriction that the pool name must begin
342 * with a letter. The pool names 'raidz' and 'mirror' are also reserved names
343 * that cannot be used.
344 *
345 * Returns 0 on success, -1 on error.
346 */
347 int
pool_namecheck(const char * pool,namecheck_err_t * why,char * what)348 pool_namecheck(const char *pool, namecheck_err_t *why, char *what)
349 {
350 const char *c;
351
352 /*
353 * Make sure the name is not too long.
354 * If we're creating a pool with version >= SPA_VERSION_DSL_SCRUB (v11)
355 * we need to account for additional space needed by the origin ds which
356 * will also be snapshotted: "poolname"+"/"+"$ORIGIN"+"@"+"$ORIGIN".
357 * Play it safe and enforce this limit even if the pool version is < 11
358 * so it can be upgraded without issues.
359 */
360 if (strlen(pool) >= (ZFS_MAX_DATASET_NAME_LEN - 2 -
361 strlen(ORIGIN_DIR_NAME) * 2)) {
362 if (why)
363 *why = NAME_ERR_TOOLONG;
364 return (-1);
365 }
366
367 c = pool;
368 while (*c != '\0') {
369 if (!valid_char(*c)) {
370 if (why) {
371 *why = NAME_ERR_INVALCHAR;
372 *what = *c;
373 }
374 return (-1);
375 }
376 c++;
377 }
378
379 if (!(*pool >= 'a' && *pool <= 'z') &&
380 !(*pool >= 'A' && *pool <= 'Z')) {
381 if (why)
382 *why = NAME_ERR_NOLETTER;
383 return (-1);
384 }
385
386 if (strcmp(pool, "mirror") == 0 || strcmp(pool, "raidz") == 0) {
387 if (why)
388 *why = NAME_ERR_RESERVED;
389 return (-1);
390 }
391
392 if (pool[0] == 'c' && (pool[1] >= '0' && pool[1] <= '9')) {
393 if (why)
394 *why = NAME_ERR_DISKLIKE;
395 return (-1);
396 }
397
398 return (0);
399 }
400