Re: [Qemu-devel] [PATCH v2 0/2] Avoid sending zero-size packets

[Stefan Hajnoczi <stefanha@gmail.com>]

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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
> 
> 

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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