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/quotaops.h>
16 #include <linux/security.h>
18 /* Taken over from the old code... */
20 /* POSIX UID/GID verification for setting inode attributes. */
21 int inode_change_ok(struct inode *inode, struct iattr *attr)
24 unsigned int ia_valid = attr->ia_valid;
26 /* If force is set do it anyway. */
27 if (ia_valid & ATTR_FORCE)
30 /* Make sure a caller can chown. */
31 if ((ia_valid & ATTR_UID) &&
32 (current->fsuid != inode->i_uid ||
33 attr->ia_uid != inode->i_uid) && !capable(CAP_CHOWN))
36 /* Make sure caller can chgrp. */
37 if ((ia_valid & ATTR_GID) &&
38 (current->fsuid != inode->i_uid ||
39 (!in_group_p(attr->ia_gid) && attr->ia_gid != inode->i_gid)) &&
43 /* Make sure a caller can chmod. */
44 if (ia_valid & ATTR_MODE) {
45 if (!is_owner_or_cap(inode))
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;
53 /* Check for setting the inode time. */
54 if (ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) {
55 if (!is_owner_or_cap(inode))
64 EXPORT_SYMBOL(inode_change_ok);
66 int inode_setattr(struct inode * inode, struct iattr * attr)
68 unsigned int ia_valid = attr->ia_valid;
70 if (ia_valid & ATTR_SIZE &&
71 attr->ia_size != i_size_read(inode)) {
72 int error = vmtruncate(inode, attr->ia_size);
77 if (ia_valid & ATTR_UID)
78 inode->i_uid = attr->ia_uid;
79 if (ia_valid & ATTR_GID)
80 inode->i_gid = attr->ia_gid;
81 if (ia_valid & ATTR_ATIME)
82 inode->i_atime = timespec_trunc(attr->ia_atime,
83 inode->i_sb->s_time_gran);
84 if (ia_valid & ATTR_MTIME)
85 inode->i_mtime = timespec_trunc(attr->ia_mtime,
86 inode->i_sb->s_time_gran);
87 if (ia_valid & ATTR_CTIME)
88 inode->i_ctime = timespec_trunc(attr->ia_ctime,
89 inode->i_sb->s_time_gran);
90 if (ia_valid & ATTR_MODE) {
91 umode_t mode = attr->ia_mode;
93 if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
97 mark_inode_dirty(inode);
101 EXPORT_SYMBOL(inode_setattr);
103 int notify_change(struct dentry * dentry, struct iattr * attr)
105 struct inode *inode = dentry->d_inode;
106 mode_t mode = inode->i_mode;
109 unsigned int ia_valid = attr->ia_valid;
111 now = current_fs_time(inode->i_sb);
113 attr->ia_ctime = now;
114 if (!(ia_valid & ATTR_ATIME_SET))
115 attr->ia_atime = now;
116 if (!(ia_valid & ATTR_MTIME_SET))
117 attr->ia_mtime = now;
118 if (ia_valid & ATTR_KILL_PRIV) {
119 attr->ia_valid &= ~ATTR_KILL_PRIV;
120 ia_valid &= ~ATTR_KILL_PRIV;
121 error = security_inode_need_killpriv(dentry);
123 error = security_inode_killpriv(dentry);
129 * We now pass ATTR_KILL_S*ID to the lower level setattr function so
130 * that the function has the ability to reinterpret a mode change
131 * that's due to these bits. This adds an implicit restriction that
132 * no function will ever call notify_change with both ATTR_MODE and
133 * ATTR_KILL_S*ID set.
135 if ((ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) &&
136 (ia_valid & ATTR_MODE))
139 if (ia_valid & ATTR_KILL_SUID) {
140 if (mode & S_ISUID) {
141 ia_valid = attr->ia_valid |= ATTR_MODE;
142 attr->ia_mode = (inode->i_mode & ~S_ISUID);
145 if (ia_valid & ATTR_KILL_SGID) {
146 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
147 if (!(ia_valid & ATTR_MODE)) {
148 ia_valid = attr->ia_valid |= ATTR_MODE;
149 attr->ia_mode = inode->i_mode;
151 attr->ia_mode &= ~S_ISGID;
154 if (!(attr->ia_valid & ~(ATTR_KILL_SUID | ATTR_KILL_SGID)))
157 if (ia_valid & ATTR_SIZE)
158 down_write(&dentry->d_inode->i_alloc_sem);
160 if (inode->i_op && inode->i_op->setattr) {
161 error = security_inode_setattr(dentry, attr);
163 error = inode->i_op->setattr(dentry, attr);
165 error = inode_change_ok(inode, attr);
167 error = security_inode_setattr(dentry, attr);
169 if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
170 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid))
171 error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
173 error = inode_setattr(inode, attr);
177 if (ia_valid & ATTR_SIZE)
178 up_write(&dentry->d_inode->i_alloc_sem);
181 fsnotify_change(dentry, ia_valid);
186 EXPORT_SYMBOL(notify_change);