On Mon, Jul 22, 2019 at 01:24:44PM +0000, Oleinik, Alexander wrote:
> While fuzzing the virtio-net tx vq, I ran into an assertion failure due
> to iov_copy offsets larger than the total iov size. Though there is
> a check to cover this, it does not execute when !n->has_vnet_hdr. This
> patch tries to fix this.
> The call stack for the assertion failure:
>
> #8 in __assert_fail (libc.so.6+0x300f1)
> #9 in iov_copy iov.c:266:5
> #10 in virtio_net_flush_tx virtio-net.c:2073:23
> #11 in virtio_net_tx_bh virtio-net.c:2197:11
> #12 in aio_bh_poll async.c:118:13
> #13 in aio_dispatch aio-posix.c:460:5
> #14 in aio_ctx_dispatch async.c:261:5
> #15 in g_main_context_dispatch (libglib-2.0.so.0+0x4df2d)
> #16 in glib_pollfds_poll main-loop.c:213:9
> #17 in os_host_main_loop_wait main-loop.c:236
> #18 in main_loop_wait main-loop.c:512
> #19 in virtio_net_tx_fuzz virtio-net-fuzz.c:160:3
>
> v2: add details to comment for the change to qemu_sendv_packet_async
>
> Alexander Oleinik (2):
> net: assert that tx packets have nonzero size
> virtio-net: check that tx packet has positive size
>
> hw/net/virtio-net.c | 15 +++++++++------
> net/net.c | 9 +++++++++
> 2 files changed, 18 insertions(+), 6 deletions(-)
>
> --
> 2.20.1
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