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authorAkira Fujita <a-fujita@rs.jp.nec.com>2009-12-06 23:38:31 -0500
committerTheodore Ts'o <tytso@mit.edu>2009-12-06 23:38:31 -0500
commit4a58579b9e4e2a35d57e6c9c8483e52f6f1b7fd6 (patch)
treef3a7f898a081d0917f7fe7f051aba687308cbf0a
parentb436b9bef84de6893e86346d8fbf7104bc520645 (diff)
ext4: Fix insufficient checks in EXT4_IOC_MOVE_EXT
This patch fixes three problems in the handling of the EXT4_IOC_MOVE_EXT ioctl: 1. In current EXT4_IOC_MOVE_EXT, there are read access mode checks for original and donor files, but they allow the illegal write access to donor file, since donor file is overwritten by original file data. To fix this problem, change access mode checks of original (r->r/w) and donor (r->w) files. 2. Disallow the use of donor files that have a setuid or setgid bits. 3. Call mnt_want_write() and mnt_drop_write() before and after ext4_move_extents() calling to get write access to a mount. Signed-off-by: Akira Fujita <a-fujita@rs.jp.nec.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
-rw-r--r--fs/ext4/ioctl.c30
-rw-r--r--fs/ext4/move_extent.c7
2 files changed, 25 insertions, 12 deletions
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 31e5ee0c858f..b63d193126db 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -221,32 +221,38 @@ setversion_out:
struct file *donor_filp;
int err;
+ if (!(filp->f_mode & FMODE_READ) ||
+ !(filp->f_mode & FMODE_WRITE))
+ return -EBADF;
+
if (copy_from_user(&me,
(struct move_extent __user *)arg, sizeof(me)))
return -EFAULT;
+ me.moved_len = 0;
donor_filp = fget(me.donor_fd);
if (!donor_filp)
return -EBADF;
- if (!capable(CAP_DAC_OVERRIDE)) {
- if ((current->real_cred->fsuid != inode->i_uid) ||
- !(inode->i_mode & S_IRUSR) ||
- !(donor_filp->f_dentry->d_inode->i_mode &
- S_IRUSR)) {
- fput(donor_filp);
- return -EACCES;
- }
+ if (!(donor_filp->f_mode & FMODE_WRITE)) {
+ err = -EBADF;
+ goto mext_out;
}
- me.moved_len = 0;
+ err = mnt_want_write(filp->f_path.mnt);
+ if (err)
+ goto mext_out;
+
err = ext4_move_extents(filp, donor_filp, me.orig_start,
me.donor_start, me.len, &me.moved_len);
- fput(donor_filp);
+ mnt_drop_write(filp->f_path.mnt);
+ if (me.moved_len > 0)
+ file_remove_suid(donor_filp);
if (copy_to_user((struct move_extent *)arg, &me, sizeof(me)))
- return -EFAULT;
-
+ err = -EFAULT;
+mext_out:
+ fput(donor_filp);
return err;
}
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index cad1e2edda7e..82c415be87a4 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -957,6 +957,13 @@ mext_check_arguments(struct inode *orig_inode,
return -EINVAL;
}
+ if (donor_inode->i_mode & (S_ISUID|S_ISGID)) {
+ ext4_debug("ext4 move extent: suid or sgid is set"
+ " to donor file [ino:orig %lu, donor %lu]\n",
+ orig_inode->i_ino, donor_inode->i_ino);
+ return -EINVAL;
+ }
+
/* Ext4 move extent does not support swapfile */
if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
ext4_debug("ext4 move extent: The argument files should "