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 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 /*
29  * Common name validation routines for ZFS.  These routines are shared by the
30  * userland code as well as the ioctl() layer to ensure that we don't
31  * inadvertently expose a hole through direct ioctl()s that never gets tested.
32  * In userland, however, we want significantly more information about _why_ the
33  * name is invalid.  In the kernel, we only care whether it's valid or not.
34  * Each routine therefore takes a 'namecheck_err_t' which describes exactly why
35  * the name failed to validate.
36  *
37  * Each function returns 0 on success, -1 on error.
38  */
39 
40 #if defined(_KERNEL)
41 #include <sys/systm.h>
42 #else
43 #include <string.h>
44 #endif
45 
46 #include <sys/param.h>
47 #include <sys/nvpair.h>
48 #include "zfs_namecheck.h"
49 #include "zfs_deleg.h"
50 
51 static int
52 valid_char(char c)
53 {
54 	return ((c >= 'a' && c <= 'z') ||
55 	    (c >= 'A' && c <= 'Z') ||
56 	    (c >= '0' && c <= '9') ||
57 	    c == '-' || c == '_' || c == '.' || c == ':');
58 }
59 
60 /*
61  * Snapshot names must be made up of alphanumeric characters plus the following
62  * characters:
63  *
64  * 	[-_.:]
65  */
66 int
67 snapshot_namecheck(const char *path, namecheck_err_t *why, char *what)
68 {
69 	const char *loc;
70 
71 	if (strlen(path) >= MAXNAMELEN) {
72 		if (why)
73 			*why = NAME_ERR_TOOLONG;
74 		return (-1);
75 	}
76 
77 	if (path[0] == '\0') {
78 		if (why)
79 			*why = NAME_ERR_EMPTY_COMPONENT;
80 		return (-1);
81 	}
82 
83 	for (loc = path; *loc; loc++) {
84 		if (!valid_char(*loc)) {
85 			if (why) {
86 				*why = NAME_ERR_INVALCHAR;
87 				*what = *loc;
88 			}
89 			return (-1);
90 		}
91 	}
92 	return (0);
93 }
94 
95 
96 /*
97  * Permissions set name must start with the letter '@' followed by the
98  * same character restrictions as snapshot names, except that the name
99  * cannot exceed 64 characters.
100  */
101 int
102 permset_namecheck(const char *path, namecheck_err_t *why, char *what)
103 {
104 	if (strlen(path) >= ZFS_PERMSET_MAXLEN) {
105 		if (why)
106 			*why = NAME_ERR_TOOLONG;
107 		return (-1);
108 	}
109 
110 	if (path[0] != '@') {
111 		if (why) {
112 			*why = NAME_ERR_NO_AT;
113 			*what = path[0];
114 		}
115 		return (-1);
116 	}
117 
118 	return (snapshot_namecheck(&path[1], why, what));
119 }
120 
121 /*
122  * Dataset names must be of the following form:
123  *
124  * 	[component][/]*[component][@component]
125  *
126  * Where each component is made up of alphanumeric characters plus the following
127  * characters:
128  *
129  * 	[-_.:%]
130  *
131  * We allow '%' here as we use that character internally to create unique
132  * names for temporary clones (for online recv).
133  */
134 int
135 dataset_namecheck(const char *path, namecheck_err_t *why, char *what)
136 {
137 	const char *loc, *end;
138 	int found_snapshot;
139 
140 	/*
141 	 * Make sure the name is not too long.
142 	 *
143 	 * ZFS_MAXNAMELEN is the maximum dataset length used in the userland
144 	 * which is the same as MAXNAMELEN used in the kernel.
145 	 * If ZFS_MAXNAMELEN value is changed, make sure to cleanup all
146 	 * places using MAXNAMELEN.
147 	 */
148 
149 	if (strlen(path) >= MAXNAMELEN) {
150 		if (why)
151 			*why = NAME_ERR_TOOLONG;
152 		return (-1);
153 	}
154 
155 	/* Explicitly check for a leading slash.  */
156 	if (path[0] == '/') {
157 		if (why)
158 			*why = NAME_ERR_LEADING_SLASH;
159 		return (-1);
160 	}
161 
162 	if (path[0] == '\0') {
163 		if (why)
164 			*why = NAME_ERR_EMPTY_COMPONENT;
165 		return (-1);
166 	}
167 
168 	loc = path;
169 	found_snapshot = 0;
170 	for (;;) {
171 		/* Find the end of this component */
172 		end = loc;
173 		while (*end != '/' && *end != '@' && *end != '\0')
174 			end++;
175 
176 		if (*end == '\0' && end[-1] == '/') {
177 			/* trailing slashes are not allowed */
178 			if (why)
179 				*why = NAME_ERR_TRAILING_SLASH;
180 			return (-1);
181 		}
182 
183 		/* Zero-length components are not allowed */
184 		if (loc == end) {
185 			if (why) {
186 				/*
187 				 * Make sure this is really a zero-length
188 				 * component and not a '@@'.
189 				 */
190 				if (*end == '@' && found_snapshot) {
191 					*why = NAME_ERR_MULTIPLE_AT;
192 				} else {
193 					*why = NAME_ERR_EMPTY_COMPONENT;
194 				}
195 			}
196 
197 			return (-1);
198 		}
199 
200 		/* Validate the contents of this component */
201 		while (loc != end) {
202 			if (!valid_char(*loc) && *loc != '%') {
203 				if (why) {
204 					*why = NAME_ERR_INVALCHAR;
205 					*what = *loc;
206 				}
207 				return (-1);
208 			}
209 			loc++;
210 		}
211 
212 		/* If we've reached the end of the string, we're OK */
213 		if (*end == '\0')
214 			return (0);
215 
216 		if (*end == '@') {
217 			/*
218 			 * If we've found an @ symbol, indicate that we're in
219 			 * the snapshot component, and report a second '@'
220 			 * character as an error.
221 			 */
222 			if (found_snapshot) {
223 				if (why)
224 					*why = NAME_ERR_MULTIPLE_AT;
225 				return (-1);
226 			}
227 
228 			found_snapshot = 1;
229 		}
230 
231 		/*
232 		 * If there is a '/' in a snapshot name
233 		 * then report an error
234 		 */
235 		if (*end == '/' && found_snapshot) {
236 			if (why)
237 				*why = NAME_ERR_TRAILING_SLASH;
238 			return (-1);
239 		}
240 
241 		/* Update to the next component */
242 		loc = end + 1;
243 	}
244 }
245 
246 
247 /*
248  * mountpoint names must be of the following form:
249  *
250  *	/[component][/]*[component][/]
251  */
252 int
253 mountpoint_namecheck(const char *path, namecheck_err_t *why)
254 {
255 	const char *start, *end;
256 
257 	/*
258 	 * Make sure none of the mountpoint component names are too long.
259 	 * If a component name is too long then the mkdir of the mountpoint
260 	 * will fail but then the mountpoint property will be set to a value
261 	 * that can never be mounted.  Better to fail before setting the prop.
262 	 * Extra slashes are OK, they will be tossed by the mountpoint mkdir.
263 	 */
264 
265 	if (path == NULL || *path != '/') {
266 		if (why)
267 			*why = NAME_ERR_LEADING_SLASH;
268 		return (-1);
269 	}
270 
271 	/* Skip leading slash  */
272 	start = &path[1];
273 	do {
274 		end = start;
275 		while (*end != '/' && *end != '\0')
276 			end++;
277 
278 		if (end - start >= MAXNAMELEN) {
279 			if (why)
280 				*why = NAME_ERR_TOOLONG;
281 			return (-1);
282 		}
283 		start = end + 1;
284 
285 	} while (*end != '\0');
286 
287 	return (0);
288 }
289 
290 /*
291  * For pool names, we have the same set of valid characters as described in
292  * dataset names, with the additional restriction that the pool name must begin
293  * with a letter.  The pool names 'raidz' and 'mirror' are also reserved names
294  * that cannot be used.
295  */
296 int
297 pool_namecheck(const char *pool, namecheck_err_t *why, char *what)
298 {
299 	const char *c;
300 
301 	/*
302 	 * Make sure the name is not too long.
303 	 *
304 	 * ZPOOL_MAXNAMELEN is the maximum pool length used in the userland
305 	 * which is the same as MAXNAMELEN used in the kernel.
306 	 * If ZPOOL_MAXNAMELEN value is changed, make sure to cleanup all
307 	 * places using MAXNAMELEN.
308 	 */
309 	if (strlen(pool) >= MAXNAMELEN) {
310 		if (why)
311 			*why = NAME_ERR_TOOLONG;
312 		return (-1);
313 	}
314 
315 	c = pool;
316 	while (*c != '\0') {
317 		if (!valid_char(*c)) {
318 			if (why) {
319 				*why = NAME_ERR_INVALCHAR;
320 				*what = *c;
321 			}
322 			return (-1);
323 		}
324 		c++;
325 	}
326 
327 	if (!(*pool >= 'a' && *pool <= 'z') &&
328 	    !(*pool >= 'A' && *pool <= 'Z')) {
329 		if (why)
330 			*why = NAME_ERR_NOLETTER;
331 		return (-1);
332 	}
333 
334 	if (strcmp(pool, "mirror") == 0 || strcmp(pool, "raidz") == 0) {
335 		if (why)
336 			*why = NAME_ERR_RESERVED;
337 		return (-1);
338 	}
339 
340 	if (pool[0] == 'c' && (pool[1] >= '0' && pool[1] <= '9')) {
341 		if (why)
342 			*why = NAME_ERR_DISKLIKE;
343 		return (-1);
344 	}
345 
346 	return (0);
347 }
348 
349 /*
350  * Check if the dataset name is private for internal usage.
351  * '$' is reserved for internal dataset names. e.g. "$MOS"
352  *
353  * Return 1 if the given name is used internally.
354  * Return 0 if it is not.
355  */
356 int
357 dataset_name_hidden(const char *name)
358 {
359 	if (strchr(name, '$') != NULL)
360 		return (1);
361 
362 	return (0);
363 }
364