Re: linux kernel memory corruption with ipv6 udp offloading

[Kurt Seifried <kseifried () redhat com>]

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On 09/28/2013 12:30 AM, Hannes Frederic Sowa wrote:
> Hi!
>
> I guess the following patch might be worth a CVE:
>
> | [PATCH] ipv6: udp packets following an UFO enqueued packet need
> also be handled by UFO | | In the following scenario the socket is
> corked: | If the first UDP packet is larger then the mtu we try to
> append it to the | write queue via ip6_ufo_append_data. A following
> packet, which is smaller | than the mtu would be appended to the
> already queued up gso-skb via | plain ip6_append_data. This causes
> random memory corruptions. | | In ip6_ufo_append_data we also have
> to be careful to not queue up the | same skb multiple times. So
> setup the gso frame only when no first skb | is available. | | This
> also fixes a shortcoming where we add the current packet's length
> to | cork->length but return early because of a packet > mtu with
> dontfrag set | (instead of sutracting it again). | | Found with
> trinity.
>
> While writing a reproducer to test this patch, I have seen silent
> memory corruption (which later manifests as e.g. a panic or hangs
> on shutdown) and oopses.
>
> It has been reported to netdev by Dmitry Vyukov
> <dvyukov () google com> and was found with the AddressSanitizer for
> the kernel[1] and trinity.
>
> The patch is queued up for stable: 
> http://patchwork.ozlabs.org/patch/276835/ and is already committed
> to linux-net: 
> https://git.kernel.org/cgit/linux/kernel/git/davem/net.git/commit/?id=2811ebac2521ceac84f2bdae402455baa6a7fb47
>
>  I guess the erroneous behaviour was introduced here: | git
> describe --contains e89e9cf539a28df7d0eb1d0a545368e9920b34ac |
> v2.6.15-rc1~731^2~31
>
> The reproducers are available on request.
>
> [1]
> https://code.google.com/p/address-sanitizer/wiki/AddressSanitizerForKernel
>
>  Thanks,
>
> Hannes

Please use CVE-2013-4387 for this issue.

- -- 
Kurt Seifried Red Hat Security Response Team (SRT)
PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993
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