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 (c) 1990, 2010, Oracle and/or its affiliates. All rights reserved.
23 */
24
25 #include <sys/types.h>
26 #include <sys/errno.h>
27 #include <sys/param.h>
28 #include <sys/t_lock.h>
29 #include <sys/systm.h>
30 #include <sys/sysmacros.h>
31 #include <sys/debug.h>
32 #include <sys/time.h>
33 #include <sys/cmn_err.h>
34 #include <sys/vnode.h>
35 #include <sys/stat.h>
36 #include <sys/vfs.h>
37 #include <sys/cred.h>
38 #include <sys/kmem.h>
39 #include <sys/atomic.h>
40 #include <sys/policy.h>
41 #include <sys/fs/tmp.h>
42 #include <sys/fs/tmpnode.h>
43
44 #define MODESHIFT 3
45
46 int
47 tmp_taccess(void *vtp, int mode, struct cred *cred)
48 {
49 struct tmpnode *tp = vtp;
50 int shift = 0;
51 /*
52 * Check access based on owner, group and
53 * public permissions in tmpnode.
54 */
55 if (crgetuid(cred) != tp->tn_uid) {
56 shift += MODESHIFT;
57 if (groupmember(tp->tn_gid, cred) == 0)
58 shift += MODESHIFT;
59 }
60
61 return (secpolicy_vnode_access2(cred, TNTOV(tp), tp->tn_uid,
62 tp->tn_mode << shift, mode));
63 }
64
65 /*
66 * Decide whether it is okay to remove within a sticky directory.
67 * Two conditions need to be met: write access to the directory
68 * is needed. In sticky directories, write access is not sufficient;
69 * you can remove entries from a directory only if you own the directory,
70 * if you are privileged, if you own the entry or if they entry is
71 * a plain file and you have write access to that file.
72 * Function returns 0 if remove access is granted.
73 */
74
75 int
76 tmp_sticky_remove_access(struct tmpnode *dir, struct tmpnode *entry,
77 struct cred *cr)
78 {
79 uid_t uid = crgetuid(cr);
80
81 if ((dir->tn_mode & S_ISVTX) &&
82 uid != dir->tn_uid &&
83 uid != entry->tn_uid &&
84 (entry->tn_type != VREG ||
85 tmp_taccess(entry, VWRITE, cr) != 0))
86 return (secpolicy_vnode_remove(cr));
87
88 return (0);
89 }
90
91 /*
92 * Allocate zeroed memory if tmpfs_maxkmem has not been exceeded
93 * or the 'musthave' flag is set. 'musthave' allocations should
94 * always be subordinate to normal allocations so that tmpfs_maxkmem
111 if (last_warning != now) {
112 last_warning = now;
113 cmn_err(CE_WARN, "tmp_memalloc: tmpfs over memory limit");
114 }
115 return (NULL);
116 }
117
118 void
119 tmp_memfree(void *cp, size_t size)
120 {
121 kmem_free(cp, size);
122 atomic_add_long(&tmp_kmemspace, -size);
123 }
124
125 /*
126 * Convert a string containing a number (number of bytes) to a pgcnt_t,
127 * containing the corresponding number of pages. On 32-bit kernels, the
128 * maximum value encoded in 'str' is PAGESIZE * ULONG_MAX, while the value
129 * returned in 'maxpg' is at most ULONG_MAX.
130 *
131 * If the number is followed by a "k" or "K", the value is converted from
132 * kilobytes to bytes. If it is followed by an "m" or "M" it is converted
133 * from megabytes to bytes. If it is not followed by a character it is
134 * assumed to be in bytes. Multiple letter options are allowed, so for instance
135 * '2mk' is interpreted as 2gb.
136 *
137 * Parse and overflow errors are detected and a non-zero number returned on
138 * error.
139 */
140
141 int
142 tmp_convnum(char *str, pgcnt_t *maxpg)
143 {
144 uint64_t num = 0, oldnum;
145 #ifdef _LP64
146 uint64_t max_bytes = ULONG_MAX;
147 #else
148 uint64_t max_bytes = PAGESIZE * (uint64_t)ULONG_MAX;
149 #endif
150 char *c;
151
152 if (str == NULL)
153 return (EINVAL);
154 c = str;
155
156 /*
157 * Convert str to number
158 */
159 while ((*c >= '0') && (*c <= '9')) {
160 oldnum = num;
161 num = num * 10 + (*c++ - '0');
162 if (oldnum > num) /* overflow */
163 return (EINVAL);
164 }
165
166 /*
167 * Terminate on null
168 */
169 while (*c != '\0') {
170 switch (*c++) {
171
172 /*
173 * convert from kilobytes
174 */
175 case 'k':
176 case 'K':
177 if (num > max_bytes / 1024) /* will overflow */
178 return (EINVAL);
179 num *= 1024;
180 break;
181
182 /*
183 * convert from megabytes
184 */
185 case 'm':
186 case 'M':
187 if (num > max_bytes / (1024 * 1024)) /* will overflow */
188 return (EINVAL);
189 num *= 1024 * 1024;
190 break;
191
192 default:
193 return (EINVAL);
194 }
195 }
196
197 /*
198 * Since btopr() rounds up to page granularity, this round-up can
199 * cause an overflow only if 'num' is between (max_bytes - PAGESIZE)
200 * and (max_bytes). In this case the resulting number is zero, which
201 * is what we check for below.
202 */
203 if ((*maxpg = (pgcnt_t)btopr(num)) == 0 && num != 0)
204 return (EINVAL);
205 return (0);
206 }
|
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 (c) 1990, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright 2015 Joyent, Inc.
24 */
25
26 #include <sys/types.h>
27 #include <sys/errno.h>
28 #include <sys/param.h>
29 #include <sys/t_lock.h>
30 #include <sys/systm.h>
31 #include <sys/sysmacros.h>
32 #include <sys/debug.h>
33 #include <sys/time.h>
34 #include <sys/cmn_err.h>
35 #include <sys/vnode.h>
36 #include <sys/stat.h>
37 #include <sys/vfs.h>
38 #include <sys/cred.h>
39 #include <sys/kmem.h>
40 #include <sys/atomic.h>
41 #include <sys/policy.h>
42 #include <sys/fs/tmp.h>
43 #include <sys/fs/tmpnode.h>
44 #include <sys/ddi.h>
45 #include <sys/sunddi.h>
46
47 #define KILOBYTE 1024
48 #define MEGABYTE (1024 * KILOBYTE)
49 #define GIGABYTE (1024 * MEGABYTE)
50
51 #define MODESHIFT 3
52
53 #define VALIDMODEBITS 07777
54
55 extern pgcnt_t swapfs_minfree;
56
57 int
58 tmp_taccess(void *vtp, int mode, struct cred *cred)
59 {
60 struct tmpnode *tp = vtp;
61 int shift = 0;
62 /*
63 * Check access based on owner, group and
64 * public permissions in tmpnode.
65 */
66 if (crgetuid(cred) != tp->tn_uid) {
67 shift += MODESHIFT;
68 if (groupmember(tp->tn_gid, cred) == 0)
69 shift += MODESHIFT;
70 }
71
72 return (secpolicy_vnode_access2(cred, TNTOV(tp), tp->tn_uid,
73 tp->tn_mode << shift, mode));
74 }
75
76 /*
77 * Decide whether it is okay to remove within a sticky directory.
78 * Two conditions need to be met: write access to the directory
79 * is needed. In sticky directories, write access is not sufficient;
80 * you can remove entries from a directory only if you own the directory,
81 * if you are privileged, if you own the entry or if they entry is
82 * a plain file and you have write access to that file.
83 * Function returns 0 if remove access is granted.
84 */
85 int
86 tmp_sticky_remove_access(struct tmpnode *dir, struct tmpnode *entry,
87 struct cred *cr)
88 {
89 uid_t uid = crgetuid(cr);
90
91 if ((dir->tn_mode & S_ISVTX) &&
92 uid != dir->tn_uid &&
93 uid != entry->tn_uid &&
94 (entry->tn_type != VREG ||
95 tmp_taccess(entry, VWRITE, cr) != 0))
96 return (secpolicy_vnode_remove(cr));
97
98 return (0);
99 }
100
101 /*
102 * Allocate zeroed memory if tmpfs_maxkmem has not been exceeded
103 * or the 'musthave' flag is set. 'musthave' allocations should
104 * always be subordinate to normal allocations so that tmpfs_maxkmem
121 if (last_warning != now) {
122 last_warning = now;
123 cmn_err(CE_WARN, "tmp_memalloc: tmpfs over memory limit");
124 }
125 return (NULL);
126 }
127
128 void
129 tmp_memfree(void *cp, size_t size)
130 {
131 kmem_free(cp, size);
132 atomic_add_long(&tmp_kmemspace, -size);
133 }
134
135 /*
136 * Convert a string containing a number (number of bytes) to a pgcnt_t,
137 * containing the corresponding number of pages. On 32-bit kernels, the
138 * maximum value encoded in 'str' is PAGESIZE * ULONG_MAX, while the value
139 * returned in 'maxpg' is at most ULONG_MAX.
140 *
141 * The number may be followed by a magnitude suffix: "k" or "K" for kilobytes;
142 * "m" or "M" for megabytes; "g" or "G" for gigabytes. This interface allows
143 * for an arguably esoteric interpretation of multiple suffix characters:
144 * namely, they cascade. For example, the caller may specify "2mk", which is
145 * interpreted as 2 gigabytes. It would seem, at this late stage, that the
146 * horse has left not only the barn but indeed the country, and possibly the
147 * entire planetary system. Alternatively, the number may be followed by a
148 * single '%' sign, indicating the size is a percentage of either the zone's
149 * swap limit or the system's overall swap size.
150 *
151 * Parse and overflow errors are detected and a non-zero number returned on
152 * error.
153 */
154 int
155 tmp_convnum(char *str, pgcnt_t *maxpg)
156 {
157 u_longlong_t num = 0;
158 #ifdef _LP64
159 u_longlong_t max_bytes = ULONG_MAX;
160 #else
161 u_longlong_t max_bytes = PAGESIZE * (uint64_t)ULONG_MAX;
162 #endif
163 char *c;
164 const struct convchar {
165 char *cc_char;
166 uint64_t cc_factor;
167 } convchars[] = {
168 { "kK", KILOBYTE },
169 { "mM", MEGABYTE },
170 { "gG", GIGABYTE },
171 { NULL, 0 }
172 };
173
174 if (str == NULL) {
175 return (EINVAL);
176 }
177 c = str;
178
179 /*
180 * Convert the initial numeric portion of the input string.
181 */
182 if (ddi_strtoull(str, &c, 10, &num) != 0) {
183 return (EINVAL);
184 }
185
186 /*
187 * Handle a size in percent. Anything other than a single percent
188 * modifier is invalid. We use either the zone's swap limit or the
189 * system's total available swap size as the initial value. Perform the
190 * intermediate calculation in pages to avoid overflow.
191 */
192 if (*c == '%') {
193 u_longlong_t cap;
194
195 if (*(c + 1) != '\0')
196 return (EINVAL);
197
198 if (num > 100)
199 return (EINVAL);
200
201 cap = (u_longlong_t)curproc->p_zone->zone_max_swap_ctl;
202 if (cap == UINT64_MAX) {
203 /*
204 * Use the amount of available physical and memory swap
205 */
206 mutex_enter(&anoninfo_lock);
207 cap = TOTAL_AVAILABLE_SWAP;
208 mutex_exit(&anoninfo_lock);
209 } else {
210 cap = btop(cap);
211 }
212
213 num = ptob(cap * num / 100);
214 goto done;
215 }
216
217 /*
218 * Apply the (potentially cascading) magnitude suffixes until an
219 * invalid character is found, or the string comes to an end.
220 */
221 for (; *c != '\0'; c++) {
222 int i;
223
224 for (i = 0; convchars[i].cc_char != NULL; i++) {
225 /*
226 * Check if this character matches this multiplier
227 * class:
228 */
229 if (strchr(convchars[i].cc_char, *c) != NULL) {
230 /*
231 * Check for overflow:
232 */
233 if (num > max_bytes / convchars[i].cc_factor) {
234 return (EINVAL);
235 }
236
237 num *= convchars[i].cc_factor;
238 goto valid_char;
239 }
240 }
241
242 /*
243 * This was not a valid multiplier suffix character.
244 */
245 return (EINVAL);
246
247 valid_char:
248 continue;
249 }
250
251 done:
252 /*
253 * Since btopr() rounds up to page granularity, this round-up can
254 * cause an overflow only if 'num' is between (max_bytes - PAGESIZE)
255 * and (max_bytes). In this case the resulting number is zero, which
256 * is what we check for below.
257 */
258 if ((*maxpg = (pgcnt_t)btopr(num)) == 0 && num != 0)
259 return (EINVAL);
260 return (0);
261 }
262
263 /*
264 * Parse an octal mode string for use as the permissions set for the root
265 * of the tmpfs mount.
266 */
267 int
268 tmp_convmode(char *str, mode_t *mode)
269 {
270 ulong_t num;
271 char *c;
272
273 if (str == NULL) {
274 return (EINVAL);
275 }
276
277 if (ddi_strtoul(str, &c, 8, &num) != 0) {
278 return (EINVAL);
279 }
280
281 if ((num & ~VALIDMODEBITS) != 0) {
282 return (EINVAL);
283 }
284
285 *mode = VALIDMODEBITS & num;
286 return (0);
287 }
|