ext4: Fix the NULL reference in double_down_write_data_sem()
If EXT4_IOC_MOVE_EXT ioctl is called with NULL donor_fd, fget() in
ext4_ioctl() gets inappropriate file structure for donor; so we need
to do this check earlier, before calling double_down_write_data_sem().
Signed-off-by: Akira Fujita <a-fujita@rs.jp.nec.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 9eca1c0..7e99f4e 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -953,14 +953,6 @@
unsigned int blkbits = orig_inode->i_blkbits;
unsigned int blocksize = 1 << blkbits;
- /* Regular file check */
- if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
- ext4_debug("ext4 move extent: The argument files should be "
- "regular file [ino:orig %lu, donor %lu]\n",
- orig_inode->i_ino, donor_inode->i_ino);
- 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",
@@ -1208,6 +1200,14 @@
return -EINVAL;
}
+ /* Regular file check */
+ if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
+ ext4_debug("ext4 move extent: The argument files should be "
+ "regular file [ino:orig %lu, donor %lu]\n",
+ orig_inode->i_ino, donor_inode->i_ino);
+ return -EINVAL;
+ }
+
/* Protect orig and donor inodes against a truncate */
ret1 = mext_inode_double_lock(orig_inode, donor_inode);
if (ret1 < 0)