On 12/13/20 2:49 AM, Willem de Bruijn wrote:
> On Sat, Dec 12, 2020 at 5:01 AM Vasily Averin <v...@virtuozzo.com> wrote:
>>
>> On 12/11/20 6:37 PM, Vasily Averin wrote:
>>> It seems for me the similar problem can happen in __skb_trim_rcsum().
>>> Also I doubt that that skb_checksum_start_offset(skb) checks in
>>> __skb_postpull_rcsum() and skb_csum_unnecessary() are correct,
>>> becasue they do not guarantee that skb have correct CHECKSUM_PARTIAL.
>>> Could somebody confirm it?
>>
>> I've rechecked the code and I think now that other places are not affected,
>> i.e. skb_push_rcsum() only should be patched.
>
> Thanks for investigating this. So tun was able to insert a packet with
> csum_start + csum_off + 2 beyond the packet after trimming, using
> virtio_net_hdr.csum_...
>
> Any packet with an offset beyond the end of the packet is bogus
> really. No need to try to accept it by downgrading to CHECKSUM_NONE.
Do you mean it's better to force pskb_trim_rcsum() to return -EINVAL instead?
Thank you,
Vasily Averin
