On Mon, Sep 15, 2014 at 06:40:06PM +0200, Andreas Färber wrote:
> From: Stefan Hajnoczi <stefa...@redhat.com>
>
> Check incoming_posn to avoid out-of-bounds array accesses if the ivshmem
> server on the host sends invalid values.
>
> Cc: Cam Macdonell <c...@cs.ualberta.ca>
> Reported-by: Sebastian Krahmer <krah...@suse.de>
> Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
> [AF: Tighten upper bound check for posn in close_guest_eventfds()]
> Cc: qemu-sta...@nongnu.org
> Signed-off-by: Andreas Färber <afaer...@suse.de>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
> ---
> hw/misc/ivshmem.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
> index caeee1e..24f74f6 100644
> --- a/hw/misc/ivshmem.c
> +++ b/hw/misc/ivshmem.c
> @@ -389,6 +389,9 @@ static void close_guest_eventfds(IVShmemState *s, int
> posn)
> if (!ivshmem_has_feature(s, IVSHMEM_IOEVENTFD)) {
> return;
> }
> + if (posn < 0 || posn >= s->nb_peers) {
> + return;
> + }
>
> guest_curr_max = s->peers[posn].nb_eventfds;
>
> @@ -455,6 +458,11 @@ static void ivshmem_read(void *opaque, const uint8_t
> *buf, int size)
> }
> }
>
> + if (incoming_posn < -1) {
> + IVSHMEM_DPRINTF("invalid incoming_posn %ld\n", incoming_posn);
> + return;
> + }
> +
> /* pick off s->server_chr->msgfd and store it, posn should accompany msg
> */
> tmp_fd = qemu_chr_fe_get_msgfd(s->server_chr);
> IVSHMEM_DPRINTF("posn is %ld, fd is %d\n", incoming_posn, tmp_fd);
> --
> 1.8.4.5
