netdev - Re: [PATCH net-next] virtio-net: invoke zerocopy callback on xmit path if no tx napi

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 22 Aug 2017 11:01:08 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     mst@...hat.com
Cc:     jasowang@...hat.com, willemdebruijn.kernel@...il.com,
        den@...ipeden.com, virtualization@...ts.linux-foundation.org,
        netdev@...r.kernel.org
Subject: Re: [PATCH net-next] virtio-net: invoke zerocopy callback on xmit
 path if no tx napi

From: "Michael S. Tsirkin" <mst@...hat.com>
Date: Tue, 22 Aug 2017 20:55:56 +0300

> Which reminds me that skb_linearize in net core seems to be
> fundamentally racy - I suspect that if skb is cloned, and someone is
> trying to use the shared frags while another thread calls skb_linearize,
> we get some use after free bugs which likely mostly go undetected
> because the corrupted packets mostly go on wire and get dropped
> by checksum code.

Indeed, it does assume that the skb from which the clone was made
never has it's geometry changed.

I don't think even the TCP retransmit queue has this guarantee.