tree 5dd3e16d510ab10ee3d2c2aa843daa44ed34f25c
parent 7159a45b2bf2dcb9f49f1e27d1d3d135a0247a2f
author Kevin Wolf <kwolf@redhat.com> 1400163011 +0200
committer Kevin Wolf <kwolf@redhat.com> 1400492209 +0200

qcow1: Validate L2 table size (CVE-2014-0222)

Too large L2 table sizes cause unbounded allocations. Images actually
created by qemu-img only have 512 byte or 4k L2 tables.

To keep things consistent with cluster sizes, allow ranges between 512
bytes and 64k (in fact, down to 1 entry = 8 bytes is technically
working, but L2 table sizes smaller than a cluster don't make a lot of
sense).

This also means that the number of bytes on the virtual disk that are
described by the same L2 table is limited to at most 8k * 64k or 2^29,
preventively avoiding any integer overflows.

Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>