Squashfs: fix mount time sanity check for corrupted superblock

commit cc37f75a9ffbbfcb1c3297534f293c8284e3c5a6 upstream.

A Squashfs filesystem containing nothing but an empty directory,
although unusual and ultimately pointless, is still valid.

The directory_table >= next_table sanity check rejects these
filesystems as invalid because the directory_table is empty and
equal to next_table.

Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c
index 2da1715..4619247 100644 (file)
--- a/fs/squashfs/super.c
+++ b/fs/squashfs/super.c
@@ -290,7 +290,7 @@ handle_fragments:
 
 check_directory_table:
        /* Sanity check directory_table */
 
 check_directory_table:
        /* Sanity check directory_table */

-       if (msblk->directory_table >= next_table) {
+       if (msblk->directory_table > next_table) {

                err = -EINVAL;
                goto failed_mount;
        }
                err = -EINVAL;
                goto failed_mount;
        }