From: Prasad J Pandit <p...@fedoraproject.org> virtio back end uses set of buffers to facilitate I/O operations. If its size is too large, 'cpu_physical_memory_map' could return a null address. This would result in a null dereference while un-mapping descriptors. Add check to avoid it.
Reported-by: Qinghao Tang <luodalon...@gmail.com> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> --- hw/virtio/virtio.c | 5 +++++ 1 file changed, 5 insertions(+) Update per: -> https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg03889.html diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c index 15ee3a7..311dd0b 100644 --- a/hw/virtio/virtio.c +++ b/hw/virtio/virtio.c @@ -472,6 +472,11 @@ static void virtqueue_map_desc(unsigned int *p_num_sg, hwaddr *addr, struct iove } iov[num_sg].iov_base = cpu_physical_memory_map(pa, &len, is_write); + if (!iov[num_sg].iov_base) { + error_report("virtio: bogus descriptor or out of resources"); + exit(EXIT_FAILURE); + } + iov[num_sg].iov_len = len; addr[num_sg] = pa; -- 2.5.5
