tree cbc3875ab43ae11151bd9451696385de5cc845b2
parent 820f2bcacbdb8e537abce8cdf660ff3b2c67871c
author Linus Torvalds <torvalds@linux-foundation.org> 1532893486 -0700
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1533275726 +0200

squashfs: be more careful about metadata corruption

commit 01cfb7937a9af2abb1136c7e89fbf3fd92952956 upstream.

Anatoly Trosinenko reports that a corrupted squashfs image can cause a
kernel oops.  It turns out that squashfs can end up being confused about
negative fragment lengths.

The regular squashfs_read_data() does check for negative lengths, but
squashfs_read_metadata() did not, and the fragment size code just
blindly trusted the on-disk value.  Fix both the fragment parsing and
the metadata reading code.

Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Phillip Lougher <phillip@squashfs.org.uk>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>