]> git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blame - fs/attr.c
BKL: Remove BKL from HFS
[mirror_ubuntu-artful-kernel.git] / fs / attr.c
CommitLineData
1da177e4
LT
1/*
2 * linux/fs/attr.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * changes by Thomas Schoebel-Theuer
6 */
7
8#include <linux/module.h>
9#include <linux/time.h>
10#include <linux/mm.h>
11#include <linux/string.h>
16f7e0fe 12#include <linux/capability.h>
0eeca283 13#include <linux/fsnotify.h>
1da177e4 14#include <linux/fcntl.h>
1da177e4 15#include <linux/security.h>
1da177e4 16
2c27c65e
CH
17/**
18 * inode_change_ok - check if attribute changes to an inode are allowed
19 * @inode: inode to check
20 * @attr: attributes to change
21 *
22 * Check if we are allowed to change the attributes contained in @attr
23 * in the given inode. This includes the normal unix access permission
24 * checks, as well as checks for rlimits and others.
25 *
26 * Should be called as the first thing in ->setattr implementations,
27 * possibly after taking additional locks.
28 */
25d9e2d1 29int inode_change_ok(const struct inode *inode, struct iattr *attr)
1da177e4 30{
1da177e4
LT
31 unsigned int ia_valid = attr->ia_valid;
32
2c27c65e
CH
33 /*
34 * First check size constraints. These can't be overriden using
35 * ATTR_FORCE.
36 */
37 if (ia_valid & ATTR_SIZE) {
38 int error = inode_newsize_ok(inode, attr->ia_size);
39 if (error)
40 return error;
41 }
42
1da177e4
LT
43 /* If force is set do it anyway. */
44 if (ia_valid & ATTR_FORCE)
2c27c65e 45 return 0;
1da177e4
LT
46
47 /* Make sure a caller can chown. */
48 if ((ia_valid & ATTR_UID) &&
da9592ed 49 (current_fsuid() != inode->i_uid ||
1da177e4 50 attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
2c27c65e 51 return -EPERM;
1da177e4
LT
52
53 /* Make sure caller can chgrp. */
54 if ((ia_valid & ATTR_GID) &&
da9592ed 55 (current_fsuid() != inode->i_uid ||
1da177e4
LT
56 (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
57 !capable(CAP_CHOWN))
2c27c65e 58 return -EPERM;
1da177e4
LT
59
60 /* Make sure a caller can chmod. */
61 if (ia_valid & ATTR_MODE) {
3bd858ab 62 if (!is_owner_or_cap(inode))
2c27c65e 63 return -EPERM;
1da177e4
LT
64 /* Also check the setgid bit! */
65 if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid :
66 inode->i_gid) && !capable(CAP_FSETID))
67 attr->ia_mode &= ~S_ISGID;
68 }
69
70 /* Check for setting the inode time. */
9767d749 71 if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) {
3bd858ab 72 if (!is_owner_or_cap(inode))
2c27c65e 73 return -EPERM;
1da177e4 74 }
2c27c65e
CH
75
76 return 0;
1da177e4 77}
1da177e4
LT
78EXPORT_SYMBOL(inode_change_ok);
79
25d9e2d1 80/**
81 * inode_newsize_ok - may this inode be truncated to a given size
82 * @inode: the inode to be truncated
83 * @offset: the new size to assign to the inode
84 * @Returns: 0 on success, -ve errno on failure
85 *
7bb46a67 86 * inode_newsize_ok must be called with i_mutex held.
87 *
25d9e2d1 88 * inode_newsize_ok will check filesystem limits and ulimits to check that the
89 * new inode size is within limits. inode_newsize_ok will also send SIGXFSZ
90 * when necessary. Caller must not proceed with inode size change if failure is
91 * returned. @inode must be a file (not directory), with appropriate
92 * permissions to allow truncate (inode_newsize_ok does NOT check these
93 * conditions).
25d9e2d1 94 */
95int inode_newsize_ok(const struct inode *inode, loff_t offset)
96{
97 if (inode->i_size < offset) {
98 unsigned long limit;
99
d554ed89 100 limit = rlimit(RLIMIT_FSIZE);
25d9e2d1 101 if (limit != RLIM_INFINITY && offset > limit)
102 goto out_sig;
103 if (offset > inode->i_sb->s_maxbytes)
104 goto out_big;
105 } else {
106 /*
107 * truncation of in-use swapfiles is disallowed - it would
108 * cause subsequent swapout to scribble on the now-freed
109 * blocks.
110 */
111 if (IS_SWAPFILE(inode))
112 return -ETXTBSY;
113 }
114
115 return 0;
116out_sig:
117 send_sig(SIGXFSZ, current, 0);
118out_big:
119 return -EFBIG;
120}
121EXPORT_SYMBOL(inode_newsize_ok);
122
7bb46a67 123/**
6a1a90ad 124 * setattr_copy - copy simple metadata updates into the generic inode
7bb46a67 125 * @inode: the inode to be updated
126 * @attr: the new attributes
127 *
6a1a90ad 128 * setattr_copy must be called with i_mutex held.
7bb46a67 129 *
6a1a90ad 130 * setattr_copy updates the inode's metadata with that specified
7bb46a67 131 * in attr. Noticably missing is inode size update, which is more complex
2c27c65e 132 * as it requires pagecache updates.
7bb46a67 133 *
134 * The inode is not marked as dirty after this operation. The rationale is
135 * that for "simple" filesystems, the struct inode is the inode storage.
136 * The caller is free to mark the inode dirty afterwards if needed.
137 */
6a1a90ad 138void setattr_copy(struct inode *inode, const struct iattr *attr)
1da177e4
LT
139{
140 unsigned int ia_valid = attr->ia_valid;
4a30131e 141
1da177e4
LT
142 if (ia_valid & ATTR_UID)
143 inode->i_uid = attr->ia_uid;
144 if (ia_valid & ATTR_GID)
145 inode->i_gid = attr->ia_gid;
146 if (ia_valid & ATTR_ATIME)
147 inode->i_atime = timespec_trunc(attr->ia_atime,
148 inode->i_sb->s_time_gran);
149 if (ia_valid & ATTR_MTIME)
150 inode->i_mtime = timespec_trunc(attr->ia_mtime,
151 inode->i_sb->s_time_gran);
152 if (ia_valid & ATTR_CTIME)
153 inode->i_ctime = timespec_trunc(attr->ia_ctime,
154 inode->i_sb->s_time_gran);
155 if (ia_valid & ATTR_MODE) {
156 umode_t mode = attr->ia_mode;
157
158 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
159 mode &= ~S_ISGID;
160 inode->i_mode = mode;
161 }
7bb46a67 162}
6a1a90ad 163EXPORT_SYMBOL(setattr_copy);
7bb46a67 164
1da177e4
LT
165int notify_change(struct dentry * dentry, struct iattr * attr)
166{
167 struct inode *inode = dentry->d_inode;
6de0ec00 168 mode_t mode = inode->i_mode;
1da177e4
LT
169 int error;
170 struct timespec now;
171 unsigned int ia_valid = attr->ia_valid;
172
beb29e05
MS
173 if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) {
174 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
175 return -EPERM;
176 }
177
1da177e4
LT
178 now = current_fs_time(inode->i_sb);
179
180 attr->ia_ctime = now;
181 if (!(ia_valid & ATTR_ATIME_SET))
182 attr->ia_atime = now;
183 if (!(ia_valid & ATTR_MTIME_SET))
184 attr->ia_mtime = now;
b5376771
SH
185 if (ia_valid & ATTR_KILL_PRIV) {
186 attr->ia_valid &= ~ATTR_KILL_PRIV;
187 ia_valid &= ~ATTR_KILL_PRIV;
188 error = security_inode_need_killpriv(dentry);
189 if (error > 0)
190 error = security_inode_killpriv(dentry);
191 if (error)
192 return error;
193 }
6de0ec00
JL
194
195 /*
196 * We now pass ATTR_KILL_S*ID to the lower level setattr function so
197 * that the function has the ability to reinterpret a mode change
198 * that's due to these bits. This adds an implicit restriction that
199 * no function will ever call notify_change with both ATTR_MODE and
200 * ATTR_KILL_S*ID set.
201 */
202 if ((ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) &&
203 (ia_valid & ATTR_MODE))
204 BUG();
205
1da177e4 206 if (ia_valid & ATTR_KILL_SUID) {
1da177e4 207 if (mode & S_ISUID) {
6de0ec00
JL
208 ia_valid = attr->ia_valid |= ATTR_MODE;
209 attr->ia_mode = (inode->i_mode & ~S_ISUID);
1da177e4
LT
210 }
211 }
212 if (ia_valid & ATTR_KILL_SGID) {
1da177e4
LT
213 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
214 if (!(ia_valid & ATTR_MODE)) {
215 ia_valid = attr->ia_valid |= ATTR_MODE;
216 attr->ia_mode = inode->i_mode;
217 }
218 attr->ia_mode &= ~S_ISGID;
219 }
220 }
6de0ec00 221 if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID)))
1da177e4
LT
222 return 0;
223
a77b72da
MS
224 error = security_inode_setattr(dentry, attr);
225 if (error)
226 return error;
227
1da177e4
LT
228 if (ia_valid & ATTR_SIZE)
229 down_write(&dentry->d_inode->i_alloc_sem);
230
eef2380c 231 if (inode->i_op->setattr)
a77b72da 232 error = inode->i_op->setattr(dentry, attr);
eef2380c
CH
233 else
234 error = simple_setattr(dentry, attr);
1da177e4
LT
235
236 if (ia_valid & ATTR_SIZE)
237 up_write(&dentry->d_inode->i_alloc_sem);
238
0eeca283
RL
239 if (!error)
240 fsnotify_change(dentry, ia_valid);
241
1da177e4
LT
242 return error;
243}
244
245EXPORT_SYMBOL(notify_change);