From: Simon Horman <horms@kernel.org>
To: Julius Bairaktaris <julius@bairaktaris.de>
Cc: netdev@vger.kernel.org, dsahern@kernel.org, idosch@nvidia.com,
davem@davemloft.net, edumazet@kernel.org, kuba@kernel.org,
pabeni@redhat.com, steffen.klassert@secunet.com,
willemb@google.com, jiayuan.chen@linux.dev,
mfleming@cloudflare.com, almasrymina@google.com,
bigeasy@linutronix.de, richardbgobert@gmail.com,
ecree.xilinx@gmail.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net v4 1/4] net: make room for the tunnel header in skb_segment_list()
Date: Tue, 3 Nov 2026 12:43:46 +0000 [thread overview]
Message-ID: <20261103124346.GJ865646@horms.kernel.org> (raw)
In-Reply-To: <b27640960edcb8e072fdd2e8d282c1deee747b8a.1792838740.git.julius@bairaktaris.de>
On Sun, Nov 01, 2026 at 05:42:29PM +0100, Julius Bairaktaris wrote:
> skb_segment_list() pushes each frag_list member back to the outer MAC
> header and copies the tunnel headers in front of it, but never checks
> that the member has the headroom. A fraglist GRO packet forwarded into
> a tunnel and segmented in software then hits skb_under_panic() on IPIP,
> and on VXLAN the copy writes before the member's head (KASAN:
> slab-out-of-bounds write in skb_segment_list()).
>
> Call skb_cow_head() on each member before pushing it.
>
> Fixes: 3a1296a38d0c ("net: Support GRO/GSO fraglist chaining.")
> Signed-off-by: Julius Bairaktaris <julius@bairaktaris.de>
Reviewed-by: Simon Horman <horms@kernel.org>
next prev parent reply other threads:[~2026-11-03 12:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-01 16:42 [PATCH net v4 0/4] ipmr: forward GSO multicast packets Julius Bairaktaris
2026-11-01 16:42 ` [PATCH net v4 1/4] net: make room for the tunnel header in skb_segment_list() Julius Bairaktaris
2026-11-03 12:43 ` Simon Horman [this message]
2026-11-03 13:05 ` Eric Dumazet
2026-11-01 16:42 ` [PATCH net v4 2/4] net: gso: count the inner UDP header of encapsulated UDP GSO packets Julius Bairaktaris
2026-11-03 12:44 ` Simon Horman
2026-11-03 13:08 ` Eric Dumazet
2026-11-01 16:42 ` [PATCH net v4 3/4] ipmr: set up GSO state for tunnel vifs Julius Bairaktaris
2026-11-03 12:44 ` Simon Horman
2026-11-03 13:13 ` Eric Dumazet
2026-11-01 16:42 ` [PATCH net v4 4/4] ipmr: do not drop GSO packets that fit the MTU after segmentation Julius Bairaktaris
2026-11-03 12:44 ` Simon Horman
2026-11-03 13:15 ` Eric Dumazet
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