Commit | Line | Data |
---|---|---|
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 LT |
14 | #include <linux/fcntl.h> |
15 | #include <linux/quotaops.h> | |
16 | #include <linux/security.h> | |
1da177e4 LT |
17 | |
18 | /* Taken over from the old code... */ | |
19 | ||
20 | /* POSIX UID/GID verification for setting inode attributes. */ | |
25d9e2d1 | 21 | int inode_change_ok(const struct inode *inode, struct iattr *attr) |
1da177e4 LT |
22 | { |
23 | int retval = -EPERM; | |
24 | unsigned int ia_valid = attr->ia_valid; | |
25 | ||
26 | /* If force is set do it anyway. */ | |
27 | if (ia_valid & ATTR_FORCE) | |
28 | goto fine; | |
29 | ||
30 | /* Make sure a caller can chown. */ | |
31 | if ((ia_valid & ATTR_UID) && | |
da9592ed | 32 | (current_fsuid() != inode->i_uid || |
1da177e4 LT |
33 | attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN)) |
34 | goto error; | |
35 | ||
36 | /* Make sure caller can chgrp. */ | |
37 | if ((ia_valid & ATTR_GID) && | |
da9592ed | 38 | (current_fsuid() != inode->i_uid || |
1da177e4 LT |
39 | (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) && |
40 | !capable(CAP_CHOWN)) | |
41 | goto error; | |
42 | ||
43 | /* Make sure a caller can chmod. */ | |
44 | if (ia_valid & ATTR_MODE) { | |
3bd858ab | 45 | if (!is_owner_or_cap(inode)) |
1da177e4 LT |
46 | goto error; |
47 | /* Also check the setgid bit! */ | |
48 | if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid : | |
49 | inode->i_gid) && !capable(CAP_FSETID)) | |
50 | attr->ia_mode &= ~S_ISGID; | |
51 | } | |
52 | ||
53 | /* Check for setting the inode time. */ | |
9767d749 | 54 | if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) { |
3bd858ab | 55 | if (!is_owner_or_cap(inode)) |
1da177e4 LT |
56 | goto error; |
57 | } | |
58 | fine: | |
59 | retval = 0; | |
60 | error: | |
61 | return retval; | |
62 | } | |
1da177e4 LT |
63 | EXPORT_SYMBOL(inode_change_ok); |
64 | ||
25d9e2d1 | 65 | /** |
66 | * inode_newsize_ok - may this inode be truncated to a given size | |
67 | * @inode: the inode to be truncated | |
68 | * @offset: the new size to assign to the inode | |
69 | * @Returns: 0 on success, -ve errno on failure | |
70 | * | |
71 | * inode_newsize_ok will check filesystem limits and ulimits to check that the | |
72 | * new inode size is within limits. inode_newsize_ok will also send SIGXFSZ | |
73 | * when necessary. Caller must not proceed with inode size change if failure is | |
74 | * returned. @inode must be a file (not directory), with appropriate | |
75 | * permissions to allow truncate (inode_newsize_ok does NOT check these | |
76 | * conditions). | |
77 | * | |
78 | * inode_newsize_ok must be called with i_mutex held. | |
79 | */ | |
80 | int inode_newsize_ok(const struct inode *inode, loff_t offset) | |
81 | { | |
82 | if (inode->i_size < offset) { | |
83 | unsigned long limit; | |
84 | ||
85 | limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; | |
86 | if (limit != RLIM_INFINITY && offset > limit) | |
87 | goto out_sig; | |
88 | if (offset > inode->i_sb->s_maxbytes) | |
89 | goto out_big; | |
90 | } else { | |
91 | /* | |
92 | * truncation of in-use swapfiles is disallowed - it would | |
93 | * cause subsequent swapout to scribble on the now-freed | |
94 | * blocks. | |
95 | */ | |
96 | if (IS_SWAPFILE(inode)) | |
97 | return -ETXTBSY; | |
98 | } | |
99 | ||
100 | return 0; | |
101 | out_sig: | |
102 | send_sig(SIGXFSZ, current, 0); | |
103 | out_big: | |
104 | return -EFBIG; | |
105 | } | |
106 | EXPORT_SYMBOL(inode_newsize_ok); | |
107 | ||
1da177e4 LT |
108 | int inode_setattr(struct inode * inode, struct iattr * attr) |
109 | { | |
110 | unsigned int ia_valid = attr->ia_valid; | |
4a30131e N |
111 | |
112 | if (ia_valid & ATTR_SIZE && | |
113 | attr->ia_size != i_size_read(inode)) { | |
114 | int error = vmtruncate(inode, attr->ia_size); | |
115 | if (error) | |
116 | return error; | |
1da177e4 LT |
117 | } |
118 | ||
119 | if (ia_valid & ATTR_UID) | |
120 | inode->i_uid = attr->ia_uid; | |
121 | if (ia_valid & ATTR_GID) | |
122 | inode->i_gid = attr->ia_gid; | |
123 | if (ia_valid & ATTR_ATIME) | |
124 | inode->i_atime = timespec_trunc(attr->ia_atime, | |
125 | inode->i_sb->s_time_gran); | |
126 | if (ia_valid & ATTR_MTIME) | |
127 | inode->i_mtime = timespec_trunc(attr->ia_mtime, | |
128 | inode->i_sb->s_time_gran); | |
129 | if (ia_valid & ATTR_CTIME) | |
130 | inode->i_ctime = timespec_trunc(attr->ia_ctime, | |
131 | inode->i_sb->s_time_gran); | |
132 | if (ia_valid & ATTR_MODE) { | |
133 | umode_t mode = attr->ia_mode; | |
134 | ||
135 | if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) | |
136 | mode &= ~S_ISGID; | |
137 | inode->i_mode = mode; | |
138 | } | |
139 | mark_inode_dirty(inode); | |
4a30131e N |
140 | |
141 | return 0; | |
1da177e4 | 142 | } |
1da177e4 LT |
143 | EXPORT_SYMBOL(inode_setattr); |
144 | ||
1da177e4 LT |
145 | int notify_change(struct dentry * dentry, struct iattr * attr) |
146 | { | |
147 | struct inode *inode = dentry->d_inode; | |
6de0ec00 | 148 | mode_t mode = inode->i_mode; |
1da177e4 LT |
149 | int error; |
150 | struct timespec now; | |
151 | unsigned int ia_valid = attr->ia_valid; | |
152 | ||
beb29e05 MS |
153 | if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) { |
154 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) | |
155 | return -EPERM; | |
156 | } | |
157 | ||
1da177e4 LT |
158 | now = current_fs_time(inode->i_sb); |
159 | ||
160 | attr->ia_ctime = now; | |
161 | if (!(ia_valid & ATTR_ATIME_SET)) | |
162 | attr->ia_atime = now; | |
163 | if (!(ia_valid & ATTR_MTIME_SET)) | |
164 | attr->ia_mtime = now; | |
b5376771 SH |
165 | if (ia_valid & ATTR_KILL_PRIV) { |
166 | attr->ia_valid &= ~ATTR_KILL_PRIV; | |
167 | ia_valid &= ~ATTR_KILL_PRIV; | |
168 | error = security_inode_need_killpriv(dentry); | |
169 | if (error > 0) | |
170 | error = security_inode_killpriv(dentry); | |
171 | if (error) | |
172 | return error; | |
173 | } | |
6de0ec00 JL |
174 | |
175 | /* | |
176 | * We now pass ATTR_KILL_S*ID to the lower level setattr function so | |
177 | * that the function has the ability to reinterpret a mode change | |
178 | * that's due to these bits. This adds an implicit restriction that | |
179 | * no function will ever call notify_change with both ATTR_MODE and | |
180 | * ATTR_KILL_S*ID set. | |
181 | */ | |
182 | if ((ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) && | |
183 | (ia_valid & ATTR_MODE)) | |
184 | BUG(); | |
185 | ||
1da177e4 | 186 | if (ia_valid & ATTR_KILL_SUID) { |
1da177e4 | 187 | if (mode & S_ISUID) { |
6de0ec00 JL |
188 | ia_valid = attr->ia_valid |= ATTR_MODE; |
189 | attr->ia_mode = (inode->i_mode & ~S_ISUID); | |
1da177e4 LT |
190 | } |
191 | } | |
192 | if (ia_valid & ATTR_KILL_SGID) { | |
1da177e4 LT |
193 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { |
194 | if (!(ia_valid & ATTR_MODE)) { | |
195 | ia_valid = attr->ia_valid |= ATTR_MODE; | |
196 | attr->ia_mode = inode->i_mode; | |
197 | } | |
198 | attr->ia_mode &= ~S_ISGID; | |
199 | } | |
200 | } | |
6de0ec00 | 201 | if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID))) |
1da177e4 LT |
202 | return 0; |
203 | ||
a77b72da MS |
204 | error = security_inode_setattr(dentry, attr); |
205 | if (error) | |
206 | return error; | |
207 | ||
1da177e4 LT |
208 | if (ia_valid & ATTR_SIZE) |
209 | down_write(&dentry->d_inode->i_alloc_sem); | |
210 | ||
211 | if (inode->i_op && inode->i_op->setattr) { | |
a77b72da | 212 | error = inode->i_op->setattr(dentry, attr); |
1da177e4 LT |
213 | } else { |
214 | error = inode_change_ok(inode, attr); | |
1da177e4 LT |
215 | if (!error) { |
216 | if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) || | |
217 | (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) | |
9e3509e2 JK |
218 | error = vfs_dq_transfer(inode, attr) ? |
219 | -EDQUOT : 0; | |
1da177e4 LT |
220 | if (!error) |
221 | error = inode_setattr(inode, attr); | |
222 | } | |
223 | } | |
224 | ||
225 | if (ia_valid & ATTR_SIZE) | |
226 | up_write(&dentry->d_inode->i_alloc_sem); | |
227 | ||
0eeca283 RL |
228 | if (!error) |
229 | fsnotify_change(dentry, ia_valid); | |
230 | ||
1da177e4 LT |
231 | return error; |
232 | } | |
233 | ||
234 | EXPORT_SYMBOL(notify_change); |