Re: [PATCH] hw/net: Discard overly fragmented packets

[Thomas Huth]

On 05/07/2021 10.40, Philippe Mathieu-Daudé wrote:
> Our infrastructure can handle fragmented packets up to
> NET_MAX_FRAG_SG_LIST (64) pieces. This hard limit has
> been proven enough in production for years. If it is
> reached, it is likely an evil crafted packet. Discard it.
>
> Include the qtest reproducer provided by Alexander Bulekov:
>
>    $ make check-qtest-i386
>    ...
>    Running test qtest-i386/fuzz-vmxnet3-test
>    qemu-system-i386: net/eth.c:334: void eth_setup_ip4_fragmentation(const void 
> *, size_t, void *, size_t, size_t, size_t, _Bool):
>    Assertion `frag_offset % IP_FRAG_UNIT_SIZE == 0' failed.
>
> Cc: qemu-stable@nongnu.org
> Reported-by: OSS-Fuzz (Issue 35799)
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/460
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>   hw/net/net_tx_pkt.c             |   8 ++
>   tests/qtest/fuzz-vmxnet3-test.c | 195 ++++++++++++++++++++++++++++++++
>   MAINTAINERS                     |   1 +
>   tests/qtest/meson.build         |   1 +
>   4 files changed, 205 insertions(+)
>   create mode 100644 tests/qtest/fuzz-vmxnet3-test.c

Reviewed-by: Thomas Huth <thuth@redhat.com>

Jason, I think this would even still qualify for QEMU v6.1 ?