From: Daniel Borkmann <daniel@iogearbox.net>
To: Nikolay Aleksandrov <razor@blackwall.org>, netdev@vger.kernel.org
Cc: Martynas Pumputis <m@lambda.lt>,
"Jason A . Donenfeld" <Jason@zx2c4.com>,
wireguard@lists.zx2c4.com, kuba@kernel.org, davem@davemloft.net,
stable@vger.kernel.org
Subject: Re: [PATCH net 1/2] wireguard: device: fix metadata_dst xmit null pointer dereference
Date: Thu, 14 Apr 2022 13:28:18 +0200 [thread overview]
Message-ID: <24cac92b-4981-4ddc-9a05-32b61799e688@iogearbox.net> (raw)
In-Reply-To: <20220414104458.3097244-2-razor@blackwall.org>
On 4/14/22 12:44 PM, Nikolay Aleksandrov wrote:
> When we try to transmit an skb with md_dst attached through wireguard
> we hit a null pointer dereference[1] in wg_xmit() due to the use of
> dst_mtu() which calls into dst_blackhole_mtu() which in turn tries to
> dereference dst->dev. Since wireguard doesn't use md_dsts we should use
> skb_valid_dst() which checks for DST_METADATA flag and if it's set then
> fallback to wireguard's device mtu. That gives us the best chance of
> transmitting the packet, otherwise if the blackhole netdev is used we'd
> get ETH_MIN_MTU.
>
[...]
>
> CC: stable@vger.kernel.org
> CC: wireguard@lists.zx2c4.com
> CC: Jason A. Donenfeld <Jason@zx2c4.com>
> CC: Daniel Borkmann <daniel@iogearbox.net>
> CC: Martynas Pumputis <m@lambda.lt>
> Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
> Reported-by: Martynas Pumputis <m@lambda.lt>
> Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Looks good to me, thanks Nik!
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
next prev parent reply other threads:[~2022-04-22 0:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-14 10:44 [PATCH net 0/2] " Nikolay Aleksandrov
2022-04-14 10:44 ` [PATCH net 1/2] " Nikolay Aleksandrov
2022-04-14 11:28 ` Daniel Borkmann [this message]
2022-04-14 11:58 ` Jason A. Donenfeld
2022-04-14 10:44 ` [PATCH net 2/2] wireguard: selftests: add metadata_dst xmit selftest Nikolay Aleksandrov
2022-04-14 12:06 ` Jason A. Donenfeld
2022-04-14 12:12 ` Nikolay Aleksandrov
2022-04-14 12:24 ` Jason A. Donenfeld
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