[PATCH 3.16 306/366] squashfs: more metadata hardening

Ben Hutchings
2018-11-11T19:59:01Z

From: Linus Torvalds <torvalds@linux-foundation.org>

commit d512584780d3e6a7cacb2f482834849453d444a1 upstream.

Anatoly reports another squashfs fuzzing issue, where the decompression
parameters themselves are in a compressed block.

This causes squashfs_read_data() to be called in order to read the
decompression options before the decompression stream having been set
up, making squashfs go sideways.

Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com>
Acked-by: Phillip Lougher <phillip.lougher@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/squashfs/block.c | 2 ++
1 file changed, 2 insertions(+)

--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -166,6 +166,8 @@ int squashfs_read_data(struct super_bloc
}

if (compressed) {
+ if (!msblk->stream)
+ goto read_failure;
length = squashfs_decompress(msblk, bh, b, offset, length,
output);
if (length < 0)