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 <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 */
55int zfs_max_dataset_nesting = 50;
56
57static int
58valid_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 */
69int
70get_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 */
97int
98zfs_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 */
134int
135permset_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 */
160int
161dataset_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 */
181int
182entity_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 */
299int
300dataset_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 */
318int
319bookmark_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 */
337int
338snapshot_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 */
360int
361mountpoint_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 */
406int
407pool_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
456EXPORT_SYMBOL(entity_namecheck);
457EXPORT_SYMBOL(pool_namecheck);
458EXPORT_SYMBOL(dataset_namecheck);
459EXPORT_SYMBOL(bookmark_namecheck);
460EXPORT_SYMBOL(snapshot_namecheck);
461EXPORT_SYMBOL(zfs_component_namecheck);
462EXPORT_SYMBOL(dataset_nestcheck);
463EXPORT_SYMBOL(get_dataset_depth);
464EXPORT_SYMBOL(zfs_max_dataset_nesting);
465
466ZFS_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