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 | 14 | #include <linux/fcntl.h> |
1da177e4 | 15 | #include <linux/security.h> |
1da177e4 LT |
16 | |
17 | /* Taken over from the old code... */ | |
18 | ||
19 | /* POSIX UID/GID verification for setting inode attributes. */ | |
25d9e2d1 | 20 | int inode_change_ok(const struct inode *inode, struct iattr *attr) |
1da177e4 LT |
21 | { |
22 | int retval = -EPERM; | |
23 | unsigned int ia_valid = attr->ia_valid; | |
24 | ||
25 | /* If force is set do it anyway. */ | |
26 | if (ia_valid & ATTR_FORCE) | |
27 | goto fine; | |
28 | ||
29 | /* Make sure a caller can chown. */ | |
30 | if ((ia_valid & ATTR_UID) && | |
da9592ed | 31 | (current_fsuid() != inode->i_uid || |
1da177e4 LT |
32 | attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN)) |
33 | goto error; | |
34 | ||
35 | /* Make sure caller can chgrp. */ | |
36 | if ((ia_valid & ATTR_GID) && | |
da9592ed | 37 | (current_fsuid() != inode->i_uid || |
1da177e4 LT |
38 | (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) && |
39 | !capable(CAP_CHOWN)) | |
40 | goto error; | |
41 | ||
42 | /* Make sure a caller can chmod. */ | |
43 | if (ia_valid & ATTR_MODE) { | |
3bd858ab | 44 | if (!is_owner_or_cap(inode)) |
1da177e4 LT |
45 | goto error; |
46 | /* Also check the setgid bit! */ | |
47 | if (!in_group_p((ia_valid & ATTR_GID) ? attr->ia_gid : | |
48 | inode->i_gid) && !capable(CAP_FSETID)) | |
49 | attr->ia_mode &= ~S_ISGID; | |
50 | } | |
51 | ||
52 | /* Check for setting the inode time. */ | |
9767d749 | 53 | if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) { |
3bd858ab | 54 | if (!is_owner_or_cap(inode)) |
1da177e4 LT |
55 | goto error; |
56 | } | |
57 | fine: | |
58 | retval = 0; | |
59 | error: | |
60 | return retval; | |
61 | } | |
1da177e4 LT |
62 | EXPORT_SYMBOL(inode_change_ok); |
63 | ||
25d9e2d1 | 64 | /** |
65 | * inode_newsize_ok - may this inode be truncated to a given size | |
66 | * @inode: the inode to be truncated | |
67 | * @offset: the new size to assign to the inode | |
68 | * @Returns: 0 on success, -ve errno on failure | |
69 | * | |
70 | * inode_newsize_ok will check filesystem limits and ulimits to check that the | |
71 | * new inode size is within limits. inode_newsize_ok will also send SIGXFSZ | |
72 | * when necessary. Caller must not proceed with inode size change if failure is | |
73 | * returned. @inode must be a file (not directory), with appropriate | |
74 | * permissions to allow truncate (inode_newsize_ok does NOT check these | |
75 | * conditions). | |
76 | * | |
77 | * inode_newsize_ok must be called with i_mutex held. | |
78 | */ | |
79 | int inode_newsize_ok(const struct inode *inode, loff_t offset) | |
80 | { | |
81 | if (inode->i_size < offset) { | |
82 | unsigned long limit; | |
83 | ||
d554ed89 | 84 | limit = rlimit(RLIMIT_FSIZE); |
25d9e2d1 | 85 | if (limit != RLIM_INFINITY && offset > limit) |
86 | goto out_sig; | |
87 | if (offset > inode->i_sb->s_maxbytes) | |
88 | goto out_big; | |
89 | } else { | |
90 | /* | |
91 | * truncation of in-use swapfiles is disallowed - it would | |
92 | * cause subsequent swapout to scribble on the now-freed | |
93 | * blocks. | |
94 | */ | |
95 | if (IS_SWAPFILE(inode)) | |
96 | return -ETXTBSY; | |
97 | } | |
98 | ||
99 | return 0; | |
100 | out_sig: | |
101 | send_sig(SIGXFSZ, current, 0); | |
102 | out_big: | |
103 | return -EFBIG; | |
104 | } | |
105 | EXPORT_SYMBOL(inode_newsize_ok); | |
106 | ||
1da177e4 LT |
107 | int inode_setattr(struct inode * inode, struct iattr * attr) |
108 | { | |
109 | unsigned int ia_valid = attr->ia_valid; | |
4a30131e N |
110 | |
111 | if (ia_valid & ATTR_SIZE && | |
112 | attr->ia_size != i_size_read(inode)) { | |
113 | int error = vmtruncate(inode, attr->ia_size); | |
114 | if (error) | |
115 | return error; | |
1da177e4 LT |
116 | } |
117 | ||
118 | if (ia_valid & ATTR_UID) | |
119 | inode->i_uid = attr->ia_uid; | |
120 | if (ia_valid & ATTR_GID) | |
121 | inode->i_gid = attr->ia_gid; | |
122 | if (ia_valid & ATTR_ATIME) | |
123 | inode->i_atime = timespec_trunc(attr->ia_atime, | |
124 | inode->i_sb->s_time_gran); | |
125 | if (ia_valid & ATTR_MTIME) | |
126 | inode->i_mtime = timespec_trunc(attr->ia_mtime, | |
127 | inode->i_sb->s_time_gran); | |
128 | if (ia_valid & ATTR_CTIME) | |
129 | inode->i_ctime = timespec_trunc(attr->ia_ctime, | |
130 | inode->i_sb->s_time_gran); | |
131 | if (ia_valid & ATTR_MODE) { | |
132 | umode_t mode = attr->ia_mode; | |
133 | ||
134 | if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID)) | |
135 | mode &= ~S_ISGID; | |
136 | inode->i_mode = mode; | |
137 | } | |
138 | mark_inode_dirty(inode); | |
4a30131e N |
139 | |
140 | return 0; | |
1da177e4 | 141 | } |
1da177e4 LT |
142 | EXPORT_SYMBOL(inode_setattr); |
143 | ||
1da177e4 LT |
144 | int notify_change(struct dentry * dentry, struct iattr * attr) |
145 | { | |
146 | struct inode *inode = dentry->d_inode; | |
6de0ec00 | 147 | mode_t mode = inode->i_mode; |
1da177e4 LT |
148 | int error; |
149 | struct timespec now; | |
150 | unsigned int ia_valid = attr->ia_valid; | |
151 | ||
beb29e05 MS |
152 | if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) { |
153 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) | |
154 | return -EPERM; | |
155 | } | |
156 | ||
1da177e4 LT |
157 | now = current_fs_time(inode->i_sb); |
158 | ||
159 | attr->ia_ctime = now; | |
160 | if (!(ia_valid & ATTR_ATIME_SET)) | |
161 | attr->ia_atime = now; | |
162 | if (!(ia_valid & ATTR_MTIME_SET)) | |
163 | attr->ia_mtime = now; | |
b5376771 SH |
164 | if (ia_valid & ATTR_KILL_PRIV) { |
165 | attr->ia_valid &= ~ATTR_KILL_PRIV; | |
166 | ia_valid &= ~ATTR_KILL_PRIV; | |
167 | error = security_inode_need_killpriv(dentry); | |
168 | if (error > 0) | |
169 | error = security_inode_killpriv(dentry); | |
170 | if (error) | |
171 | return error; | |
172 | } | |
6de0ec00 JL |
173 | |
174 | /* | |
175 | * We now pass ATTR_KILL_S*ID to the lower level setattr function so | |
176 | * that the function has the ability to reinterpret a mode change | |
177 | * that's due to these bits. This adds an implicit restriction that | |
178 | * no function will ever call notify_change with both ATTR_MODE and | |
179 | * ATTR_KILL_S*ID set. | |
180 | */ | |
181 | if ((ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) && | |
182 | (ia_valid & ATTR_MODE)) | |
183 | BUG(); | |
184 | ||
1da177e4 | 185 | if (ia_valid & ATTR_KILL_SUID) { |
1da177e4 | 186 | if (mode & S_ISUID) { |
6de0ec00 JL |
187 | ia_valid = attr->ia_valid |= ATTR_MODE; |
188 | attr->ia_mode = (inode->i_mode & ~S_ISUID); | |
1da177e4 LT |
189 | } |
190 | } | |
191 | if (ia_valid & ATTR_KILL_SGID) { | |
1da177e4 LT |
192 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { |
193 | if (!(ia_valid & ATTR_MODE)) { | |
194 | ia_valid = attr->ia_valid |= ATTR_MODE; | |
195 | attr->ia_mode = inode->i_mode; | |
196 | } | |
197 | attr->ia_mode &= ~S_ISGID; | |
198 | } | |
199 | } | |
6de0ec00 | 200 | if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID))) |
1da177e4 LT |
201 | return 0; |
202 | ||
a77b72da MS |
203 | error = security_inode_setattr(dentry, attr); |
204 | if (error) | |
205 | return error; | |
206 | ||
1da177e4 LT |
207 | if (ia_valid & ATTR_SIZE) |
208 | down_write(&dentry->d_inode->i_alloc_sem); | |
209 | ||
210 | if (inode->i_op && inode->i_op->setattr) { | |
a77b72da | 211 | error = inode->i_op->setattr(dentry, attr); |
1da177e4 LT |
212 | } else { |
213 | error = inode_change_ok(inode, attr); | |
759bfee6 CH |
214 | if (!error) |
215 | error = inode_setattr(inode, attr); | |
1da177e4 LT |
216 | } |
217 | ||
218 | if (ia_valid & ATTR_SIZE) | |
219 | up_write(&dentry->d_inode->i_alloc_sem); | |
220 | ||
0eeca283 RL |
221 | if (!error) |
222 | fsnotify_change(dentry, ia_valid); | |
223 | ||
1da177e4 LT |
224 | return error; |
225 | } | |
226 | ||
227 | EXPORT_SYMBOL(notify_change); |