[9610] wlbt: SCSC Driver version 10.9.1.0
[GitHub/LineageOS/android_kernel_motorola_exynos9610.git] / fs / attr.c
CommitLineData
b2441318 1// SPDX-License-Identifier: GPL-2.0
1da177e4
LT
2/*
3 * linux/fs/attr.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 * changes by Thomas Schoebel-Theuer
7 */
8
630d9c47 9#include <linux/export.h>
1da177e4
LT
10#include <linux/time.h>
11#include <linux/mm.h>
12#include <linux/string.h>
3f07c014 13#include <linux/sched/signal.h>
16f7e0fe 14#include <linux/capability.h>
0eeca283 15#include <linux/fsnotify.h>
1da177e4 16#include <linux/fcntl.h>
1da177e4 17#include <linux/security.h>
975d2943 18#include <linux/evm.h>
9957a504 19#include <linux/ima.h>
1da177e4 20
2c27c65e 21/**
31051c85
JK
22 * setattr_prepare - check if attribute changes to a dentry are allowed
23 * @dentry: dentry to check
2c27c65e
CH
24 * @attr: attributes to change
25 *
26 * Check if we are allowed to change the attributes contained in @attr
31051c85
JK
27 * in the given dentry. This includes the normal unix access permission
28 * checks, as well as checks for rlimits and others. The function also clears
29 * SGID bit from mode if user is not allowed to set it. Also file capabilities
30 * and IMA extended attributes are cleared if ATTR_KILL_PRIV is set.
2c27c65e
CH
31 *
32 * Should be called as the first thing in ->setattr implementations,
33 * possibly after taking additional locks.
34 */
31051c85 35int setattr_prepare(struct dentry *dentry, struct iattr *attr)
1da177e4 36{
31051c85 37 struct inode *inode = d_inode(dentry);
1da177e4
LT
38 unsigned int ia_valid = attr->ia_valid;
39
2c27c65e
CH
40 /*
41 * First check size constraints. These can't be overriden using
42 * ATTR_FORCE.
43 */
44 if (ia_valid & ATTR_SIZE) {
45 int error = inode_newsize_ok(inode, attr->ia_size);
46 if (error)
47 return error;
48 }
49
1da177e4
LT
50 /* If force is set do it anyway. */
51 if (ia_valid & ATTR_FORCE)
030b533c 52 goto kill_priv;
1da177e4
LT
53
54 /* Make sure a caller can chown. */
55 if ((ia_valid & ATTR_UID) &&
8e96e3b7 56 (!uid_eq(current_fsuid(), inode->i_uid) ||
7fa294c8 57 !uid_eq(attr->ia_uid, inode->i_uid)) &&
23adbe12 58 !capable_wrt_inode_uidgid(inode, CAP_CHOWN))
2c27c65e 59 return -EPERM;
1da177e4
LT
60
61 /* Make sure caller can chgrp. */
62 if ((ia_valid & ATTR_GID) &&
8e96e3b7
EB
63 (!uid_eq(current_fsuid(), inode->i_uid) ||
64 (!in_group_p(attr->ia_gid) && !gid_eq(attr->ia_gid, inode->i_gid))) &&
23adbe12 65 !capable_wrt_inode_uidgid(inode, CAP_CHOWN))
2c27c65e 66 return -EPERM;
1da177e4
LT
67
68 /* Make sure a caller can chmod. */
69 if (ia_valid & ATTR_MODE) {
2e149670 70 if (!inode_owner_or_capable(inode))
2c27c65e 71 return -EPERM;
1da177e4
LT
72 /* Also check the setgid bit! */
73 if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
7fa294c8 74 inode->i_gid) &&
23adbe12 75 !capable_wrt_inode_uidgid(inode, CAP_FSETID))
1da177e4
LT
76 attr->ia_mode &= ~S_ISGID;
77 }
78
79 /* Check for setting the inode time. */
9767d749 80 if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) {
2e149670 81 if (!inode_owner_or_capable(inode))
2c27c65e 82 return -EPERM;
1da177e4 83 }
2c27c65e 84
030b533c
JK
85kill_priv:
86 /* User has permission for the change */
87 if (ia_valid & ATTR_KILL_PRIV) {
88 int error;
89
90 error = security_inode_killpriv(dentry);
91 if (error)
92 return error;
93 }
94
2c27c65e 95 return 0;
1da177e4 96}
31051c85 97EXPORT_SYMBOL(setattr_prepare);
1da177e4 98
25d9e2d1 99/**
100 * inode_newsize_ok - may this inode be truncated to a given size
101 * @inode: the inode to be truncated
102 * @offset: the new size to assign to the inode
103 * @Returns: 0 on success, -ve errno on failure
104 *
7bb46a67 105 * inode_newsize_ok must be called with i_mutex held.
106 *
25d9e2d1 107 * inode_newsize_ok will check filesystem limits and ulimits to check that the
108 * new inode size is within limits. inode_newsize_ok will also send SIGXFSZ
109 * when necessary. Caller must not proceed with inode size change if failure is
110 * returned. @inode must be a file (not directory), with appropriate
111 * permissions to allow truncate (inode_newsize_ok does NOT check these
112 * conditions).
25d9e2d1 113 */
114int inode_newsize_ok(const struct inode *inode, loff_t offset)
115{
116 if (inode->i_size < offset) {
117 unsigned long limit;
118
d554ed89 119 limit = rlimit(RLIMIT_FSIZE);
25d9e2d1 120 if (limit != RLIM_INFINITY && offset > limit)
121 goto out_sig;
122 if (offset > inode->i_sb->s_maxbytes)
123 goto out_big;
124 } else {
125 /*
126 * truncation of in-use swapfiles is disallowed - it would
127 * cause subsequent swapout to scribble on the now-freed
128 * blocks.
129 */
130 if (IS_SWAPFILE(inode))
131 return -ETXTBSY;
132 }
133
134 return 0;
135out_sig:
136 send_sig(SIGXFSZ, current, 0);
137out_big:
138 return -EFBIG;
139}
140EXPORT_SYMBOL(inode_newsize_ok);
141
7bb46a67 142/**
6a1a90ad 143 * setattr_copy - copy simple metadata updates into the generic inode
7bb46a67 144 * @inode: the inode to be updated
145 * @attr: the new attributes
146 *
6a1a90ad 147 * setattr_copy must be called with i_mutex held.
7bb46a67 148 *
6a1a90ad 149 * setattr_copy updates the inode's metadata with that specified
25985edc 150 * in attr. Noticeably missing is inode size update, which is more complex
2c27c65e 151 * as it requires pagecache updates.
7bb46a67 152 *
153 * The inode is not marked as dirty after this operation. The rationale is
154 * that for "simple" filesystems, the struct inode is the inode storage.
155 * The caller is free to mark the inode dirty afterwards if needed.
156 */
6a1a90ad 157void setattr_copy(struct inode *inode, const struct iattr *attr)
1da177e4
LT
158{
159 unsigned int ia_valid = attr->ia_valid;
4a30131e 160
1da177e4
LT
161 if (ia_valid & ATTR_UID)
162 inode->i_uid = attr->ia_uid;
163 if (ia_valid & ATTR_GID)
164 inode->i_gid = attr->ia_gid;
165 if (ia_valid & ATTR_ATIME)
166 inode->i_atime = timespec_trunc(attr->ia_atime,
167 inode->i_sb->s_time_gran);
168 if (ia_valid & ATTR_MTIME)
169 inode->i_mtime = timespec_trunc(attr->ia_mtime,
170 inode->i_sb->s_time_gran);
171 if (ia_valid & ATTR_CTIME)
172 inode->i_ctime = timespec_trunc(attr->ia_ctime,
173 inode->i_sb->s_time_gran);
174 if (ia_valid & ATTR_MODE) {
175 umode_t mode = attr->ia_mode;
176
7fa294c8 177 if (!in_group_p(inode->i_gid) &&
23adbe12 178 !capable_wrt_inode_uidgid(inode, CAP_FSETID))
1da177e4
LT
179 mode &= ~S_ISGID;
180 inode->i_mode = mode;
181 }
7bb46a67 182}
6a1a90ad 183EXPORT_SYMBOL(setattr_copy);
7bb46a67 184
27ac0ffe
BF
185/**
186 * notify_change - modify attributes of a filesytem object
187 * @dentry: object affected
188 * @iattr: new attributes
189 * @delegated_inode: returns inode, if the inode is delegated
190 *
191 * The caller must hold the i_mutex on the affected object.
192 *
193 * If notify_change discovers a delegation in need of breaking,
194 * it will return -EWOULDBLOCK and return a reference to the inode in
195 * delegated_inode. The caller should then break the delegation and
196 * retry. Because breaking a delegation may take a long time, the
197 * caller should drop the i_mutex before doing so.
198 *
199 * Alternatively, a caller may pass NULL for delegated_inode. This may
200 * be appropriate for callers that expect the underlying filesystem not
201 * to be NFS exported. Also, passing NULL is fine for callers holding
202 * the file open for write, as there can be no conflicting delegation in
203 * that case.
204 */
06b4c450 205int notify_change2(struct vfsmount *mnt, struct dentry * dentry, struct iattr * attr, struct inode **delegated_inode)
1da177e4
LT
206{
207 struct inode *inode = dentry->d_inode;
8d334acd 208 umode_t mode = inode->i_mode;
1da177e4
LT
209 int error;
210 struct timespec now;
211 unsigned int ia_valid = attr->ia_valid;
212
5955102c 213 WARN_ON_ONCE(!inode_is_locked(inode));
c4107b30 214
beb29e05
MS
215 if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) {
216 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
217 return -EPERM;
218 }
219
f2b20f6e
MS
220 /*
221 * If utimes(2) and friends are called with times == NULL (or both
222 * times are UTIME_NOW), then we need to check for write permission
223 */
224 if (ia_valid & ATTR_TOUCH) {
225 if (IS_IMMUTABLE(inode))
226 return -EPERM;
227
228 if (!inode_owner_or_capable(inode)) {
571be173 229 error = inode_permission2(mnt, inode, MAY_WRITE);
f2b20f6e
MS
230 if (error)
231 return error;
232 }
233 }
234
69b45732 235 if ((ia_valid & ATTR_MODE)) {
8d334acd 236 umode_t amode = attr->ia_mode;
69b45732
AK
237 /* Flag setting protected by i_mutex */
238 if (is_sxid(amode))
239 inode->i_flags &= ~S_NOSEC;
240 }
241
c2050a45 242 now = current_time(inode);
1da177e4
LT
243
244 attr->ia_ctime = now;
245 if (!(ia_valid & ATTR_ATIME_SET))
246 attr->ia_atime = now;
247 if (!(ia_valid & ATTR_MTIME_SET))
248 attr->ia_mtime = now;
b5376771 249 if (ia_valid & ATTR_KILL_PRIV) {
b5376771 250 error = security_inode_need_killpriv(dentry);
030b533c 251 if (error < 0)
b5376771 252 return error;
030b533c
JK
253 if (error == 0)
254 ia_valid = attr->ia_valid &= ~ATTR_KILL_PRIV;
b5376771 255 }
6de0ec00
JL
256
257 /*
258 * We now pass ATTR_KILL_S*ID to the lower level setattr function so
259 * that the function has the ability to reinterpret a mode change
260 * that's due to these bits. This adds an implicit restriction that
261 * no function will ever call notify_change with both ATTR_MODE and
262 * ATTR_KILL_S*ID set.
263 */
264 if ((ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) &&
265 (ia_valid & ATTR_MODE))
266 BUG();
267
1da177e4 268 if (ia_valid & ATTR_KILL_SUID) {
1da177e4 269 if (mode & S_ISUID) {
6de0ec00
JL
270 ia_valid = attr->ia_valid |= ATTR_MODE;
271 attr->ia_mode = (inode->i_mode & ~S_ISUID);
1da177e4
LT
272 }
273 }
274 if (ia_valid & ATTR_KILL_SGID) {
1da177e4
LT
275 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
276 if (!(ia_valid & ATTR_MODE)) {
277 ia_valid = attr->ia_valid |= ATTR_MODE;
278 attr->ia_mode = inode->i_mode;
279 }
280 attr->ia_mode &= ~S_ISGID;
281 }
282 }
6de0ec00 283 if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID)))
1da177e4
LT
284 return 0;
285
a475acf0
SF
286 /*
287 * Verify that uid/gid changes are valid in the target
288 * namespace of the superblock.
289 */
290 if (ia_valid & ATTR_UID &&
291 !kuid_has_mapping(inode->i_sb->s_user_ns, attr->ia_uid))
292 return -EOVERFLOW;
293 if (ia_valid & ATTR_GID &&
294 !kgid_has_mapping(inode->i_sb->s_user_ns, attr->ia_gid))
295 return -EOVERFLOW;
296
0bd23d09
EB
297 /* Don't allow modifications of files with invalid uids or
298 * gids unless those uids & gids are being made valid.
299 */
300 if (!(ia_valid & ATTR_UID) && !uid_valid(inode->i_uid))
301 return -EOVERFLOW;
302 if (!(ia_valid & ATTR_GID) && !gid_valid(inode->i_gid))
303 return -EOVERFLOW;
304
a77b72da 305 error = security_inode_setattr(dentry, attr);
27ac0ffe
BF
306 if (error)
307 return error;
308 error = try_break_deleg(inode, delegated_inode);
a77b72da
MS
309 if (error)
310 return error;
311
06b4c450
DR
312 if (mnt && inode->i_op->setattr2)
313 error = inode->i_op->setattr2(mnt, dentry, attr);
314 else if (inode->i_op->setattr)
a77b72da 315 error = inode->i_op->setattr(dentry, attr);
eef2380c
CH
316 else
317 error = simple_setattr(dentry, attr);
1da177e4 318
975d2943 319 if (!error) {
0eeca283 320 fsnotify_change(dentry, ia_valid);
9957a504 321 ima_inode_post_setattr(dentry);
975d2943
MZ
322 evm_inode_post_setattr(dentry, ia_valid);
323 }
0eeca283 324
1da177e4
LT
325 return error;
326}
06b4c450
DR
327EXPORT_SYMBOL(notify_change2);
328
329int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **delegated_inode)
330{
331 return notify_change2(NULL, dentry, attr, delegated_inode);
332}
1da177e4 333EXPORT_SYMBOL(notify_change);