qcow2: fix offset overflow in qcow2_alloc_clusters_at()
When cluster size is big enough it can lead to an offset overflow
in qcow2_alloc_clusters_at(). This patch fixes it.
The allocation is stopped each time at L2 table boundary
(see handle_alloc()), so the possible maximum bytes could be
2^(cluster_bits - 3 + cluster_bits)
cluster_bits - 3 is used to compute the number of entry by L2
and the additional cluster_bits is to take into account each
clusters referenced by the L2 entries.
so int is safe for cluster_bits<=17, unsafe otherwise.
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Benoit Canet <benoit@irqsave.net>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
1 file changed
