4 * Copyright (C) 1991, 1992 Linus Torvalds
5 * changes by Thomas Schoebel-Theuer
8 #include <linux/module.h>
9 #include <linux/time.h>
11 #include <linux/string.h>
12 #include <linux/capability.h>
13 #include <linux/fsnotify.h>
14 #include <linux/fcntl.h>
15 #include <linux/security.h>
17 /* Taken over from the old code... */
19 /* POSIX UID/GID verification for setting inode attributes. */
20 int inode_change_ok(const struct inode *inode, struct iattr *attr)
23 unsigned int ia_valid = attr->ia_valid;
25 /* If force is set do it anyway. */
26 if (ia_valid & ATTR_FORCE)
29 /* Make sure a caller can chown. */
30 if ((ia_valid & ATTR_UID) &&
31 (current_fsuid() != inode->i_uid ||
32 attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
35 /* Make sure caller can chgrp. */
36 if ((ia_valid & ATTR_GID) &&
37 (current_fsuid() != inode->i_uid ||
38 (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
42 /* Make sure a caller can chmod. */
43 if (ia_valid & ATTR_MODE) {
44 if (!is_owner_or_cap(inode))
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;
52 /* Check for setting the inode time. */
53 if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) {
54 if (!is_owner_or_cap(inode))
62 EXPORT_SYMBOL(inode_change_ok);
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
70 * inode_newsize_ok must be called with i_mutex held.
72 * inode_newsize_ok will check filesystem limits and ulimits to check that the
73 * new inode size is within limits. inode_newsize_ok will also send SIGXFSZ
74 * when necessary. Caller must not proceed with inode size change if failure is
75 * returned. @inode must be a file (not directory), with appropriate
76 * permissions to allow truncate (inode_newsize_ok does NOT check these
79 int inode_newsize_ok(const struct inode *inode, loff_t offset)
81 if (inode->i_size < offset) {
84 limit = rlimit(RLIMIT_FSIZE);
85 if (limit != RLIM_INFINITY && offset > limit)
87 if (offset > inode->i_sb->s_maxbytes)
91 * truncation of in-use swapfiles is disallowed - it would
92 * cause subsequent swapout to scribble on the now-freed
95 if (IS_SWAPFILE(inode))
101 send_sig(SIGXFSZ, current, 0);
105 EXPORT_SYMBOL(inode_newsize_ok);
108 * setattr_copy - copy simple metadata updates into the generic inode
109 * @inode: the inode to be updated
110 * @attr: the new attributes
112 * setattr_copy must be called with i_mutex held.
114 * setattr_copy updates the inode's metadata with that specified
115 * in attr. Noticably missing is inode size update, which is more complex
116 * as it requires pagecache updates. See simple_setsize.
118 * The inode is not marked as dirty after this operation. The rationale is
119 * that for "simple" filesystems, the struct inode is the inode storage.
120 * The caller is free to mark the inode dirty afterwards if needed.
122 void setattr_copy(struct inode *inode, const struct iattr *attr)
124 unsigned int ia_valid = attr->ia_valid;
126 if (ia_valid & ATTR_UID)
127 inode->i_uid = attr->ia_uid;
128 if (ia_valid & ATTR_GID)
129 inode->i_gid = attr->ia_gid;
130 if (ia_valid & ATTR_ATIME)
131 inode->i_atime = timespec_trunc(attr->ia_atime,
132 inode->i_sb->s_time_gran);
133 if (ia_valid & ATTR_MTIME)
134 inode->i_mtime = timespec_trunc(attr->ia_mtime,
135 inode->i_sb->s_time_gran);
136 if (ia_valid & ATTR_CTIME)
137 inode->i_ctime = timespec_trunc(attr->ia_ctime,
138 inode->i_sb->s_time_gran);
139 if (ia_valid & ATTR_MODE) {
140 umode_t mode = attr->ia_mode;
142 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
144 inode->i_mode = mode;
147 EXPORT_SYMBOL(setattr_copy);
149 int notify_change(struct dentry * dentry, struct iattr * attr)
151 struct inode *inode = dentry->d_inode;
152 mode_t mode = inode->i_mode;
155 unsigned int ia_valid = attr->ia_valid;
157 if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) {
158 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
162 now = current_fs_time(inode->i_sb);
164 attr->ia_ctime = now;
165 if (!(ia_valid & ATTR_ATIME_SET))
166 attr->ia_atime = now;
167 if (!(ia_valid & ATTR_MTIME_SET))
168 attr->ia_mtime = now;
169 if (ia_valid & ATTR_KILL_PRIV) {
170 attr->ia_valid &= ~ATTR_KILL_PRIV;
171 ia_valid &= ~ATTR_KILL_PRIV;
172 error = security_inode_need_killpriv(dentry);
174 error = security_inode_killpriv(dentry);
180 * We now pass ATTR_KILL_S*ID to the lower level setattr function so
181 * that the function has the ability to reinterpret a mode change
182 * that's due to these bits. This adds an implicit restriction that
183 * no function will ever call notify_change with both ATTR_MODE and
184 * ATTR_KILL_S*ID set.
186 if ((ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) &&
187 (ia_valid & ATTR_MODE))
190 if (ia_valid & ATTR_KILL_SUID) {
191 if (mode & S_ISUID) {
192 ia_valid = attr->ia_valid |= ATTR_MODE;
193 attr->ia_mode = (inode->i_mode & ~S_ISUID);
196 if (ia_valid & ATTR_KILL_SGID) {
197 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
198 if (!(ia_valid & ATTR_MODE)) {
199 ia_valid = attr->ia_valid |= ATTR_MODE;
200 attr->ia_mode = inode->i_mode;
202 attr->ia_mode &= ~S_ISGID;
205 if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID)))
208 error = security_inode_setattr(dentry, attr);
212 if (ia_valid & ATTR_SIZE)
213 down_write(&dentry->d_inode->i_alloc_sem);
215 if (inode->i_op->setattr)
216 error = inode->i_op->setattr(dentry, attr);
218 error = simple_setattr(dentry, attr);
220 if (ia_valid & ATTR_SIZE)
221 up_write(&dentry->d_inode->i_alloc_sem);
224 fsnotify_change(dentry, ia_valid);
229 EXPORT_SYMBOL(notify_change);