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 */
57int zfs_max_dataset_nesting = 50;
58
59static int
60valid_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 */
71int
72get_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 */
99int
100zfs_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 */
136int
137permset_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 */
162int
163dataset_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 */
183int
184entity_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 */
278int
279dataset_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 */
301int
302mountpoint_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 */
347int
348pool_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