squashfs: more metadata hardening
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>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index ce62a38..cec0fa2 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -166,6 +166,8 @@
}
if (compressed) {
+ if (!msblk->stream)
+ goto read_failure;
length = squashfs_decompress(msblk, bh, b, offset, length,
output);
if (length < 0)