From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: shiming.cheng@mediatek.com, willemdebruijn.kernel@gmail.com,
edumazet@google.com, davem@davemloft.net, kuba@kernel.org,
pabeni@redhat.com, matthias.bgg@gmail.com
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
shiming.cheng@mediatek.com, Lena Wang <lena.wang@mediatek.com>,
daniel@iogearbox.net
Subject: Re: [PATCH net] net: prevent pulling SKB_GSO_FRAGLIST skb
Date: Mon, 29 Apr 2024 09:28:07 -0400 [thread overview]
Message-ID: <662fa067c7066_2e2f1d294a0@willemb.c.googlers.com.notmuch> (raw)
In-Reply-To: <20240428142913.18666-1-shiming.cheng@mediatek.com>
shiming.cheng@ wrote:
> From: Shiming Cheng <shiming.cheng@mediatek.com>
>
> BPF or TC callers may pull in a length longer than skb_headlen()
> for a SKB_GSO_FRAGLIST skb. The data in fraglist will be pulled
> into the linear space. However it destroys the skb's structure
> and may result in an invalid segmentation or kernel exception.
>
> So we should add protection to stop the operation and return
> error to remind callers.
>
> Fixes: 3a1296a38d0c ("net: Support GRO/GSO fraglist chaining.")
> Signed-off-by: Shiming Cheng <shiming.cheng@mediatek.com>
> Signed-off-by: Lena Wang <lena.wang@mediatek.com>
>
> ---
> net/core/skbuff.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index f68f2679b086..2d35e009e814 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -6100,6 +6100,12 @@ EXPORT_SYMBOL(skb_vlan_untag);
>
> int skb_ensure_writable(struct sk_buff *skb, unsigned int write_len)
> {
> + if (skb_is_gso(skb) &&
> + (skb_shinfo(skb)->gso_type & SKB_GSO_FRAGLIST) &&
> + write_len > skb_headlen(skb)) {
> + return -ENOMEM;
> + }
> +
Most callers of skb_ensure_writable pull less than headlen.
It might be good to start with the write_len check. Before
looking at gso type.
> if (!pskb_may_pull(skb, write_len))
> return -ENOMEM;
>
> --
> 2.18.0
>
next prev parent reply other threads:[~2024-04-29 13:28 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-28 14:29 [PATCH net] net: prevent pulling SKB_GSO_FRAGLIST skb shiming.cheng
2024-04-29 13:28 ` Willem de Bruijn [this message]
2024-04-29 13:42 ` Jakub Kicinski
2024-05-15 9:02 ` Lena Wang (王娜)
2024-05-16 15:11 ` Jakub Kicinski
2024-05-23 10:03 ` Lena Wang (王娜)
2024-05-23 12:46 ` Willem de Bruijn
2024-05-23 14:59 ` Willem de Bruijn
2024-05-29 11:35 ` Lena Wang (王娜)
2024-05-29 14:04 ` Willem de Bruijn
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