On 09/19/16 17:55, Stefan Hajnoczi wrote: > On Mon, Sep 19, 2016 at 02:36:11PM +0530, P J P wrote: >> 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); > > exit(1) is used everywhere else in the file (including just a few lines > above in the same function). Please use exit(1) for consistency.
Laurent's pending series [Qemu-devel] [PATCH 00/26] trivial: use exit(EXIT_SUCCESS) and exit(EXIT_FAILURE) specifically his patch [Qemu-devel] [PATCH 11/26] pci, virtio: use exit(EXIT_SUCCESS) and exit(EXIT_FAILURE) converts the argument of the exit() that you name to EXIT_FAILURE. So using EXIT_FAILURE in Prasad's patch is actually what will uphold consistency. > Looks fine otherwise. > Thanks! Laszlo