ext4: Make sure the MOVE_EXT ioctl can't overwrite append-only files
Dan Roseberg has reported a problem with the MOVE_EXT ioctl. If the
donor file is an append-only file, we should not allow the operation
to proceed, lest we end up overwriting the contents of an append-only
file.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Dan Rosenberg <dan.j.rosenberg@gmail.com>
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index 3a6c92a..52abfa1 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -960,6 +960,9 @@
return -EINVAL;
}
+ if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode))
+ return -EPERM;
+
/* 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 "