From mboxrd@z Thu Jan 1 00:00:00 1970 From: Willem de Bruijn Subject: [PATCH net-next] net: avoid skb_warn_bad_offload on IS_ERR Date: Tue, 12 Dec 2017 11:39:04 -0500 Message-ID: <20171212163904.209480-1-willemdebruijn.kernel@gmail.com> Cc: edumazet@google.com, davem@davemloft.net, Willem de Bruijn To: netdev@vger.kernel.org Return-path: Received: from mail-yb0-f196.google.com ([209.85.213.196]:33835 "EHLO mail-yb0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751625AbdLLQjI (ORCPT ); Tue, 12 Dec 2017 11:39:08 -0500 Received: by mail-yb0-f196.google.com with SMTP id z11so4009091ybm.1 for ; Tue, 12 Dec 2017 08:39:08 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: From: Willem de Bruijn skb_warn_bad_offload warns when packets enter the GSO stack that require skb_checksum_help or vice versa. Do not warn on arbitrary bad packets. Packet sockets can craft many. Syzkaller was able to demonstrate another one with eth_type games. In particular, suppress the warning when segmentation returns an error, which is for reasons other than checksum offload. See also commit 36c92474498a ("net: WARN if skb_checksum_help() is called on skb requiring segmentation") for context on this warning. Signed-off-by: Willem de Bruijn --- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/dev.c b/net/core/dev.c index 8aa2f70995e8..b0eee49a2489 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2803,7 +2803,7 @@ struct sk_buff *__skb_gso_segment(struct sk_buff *skb, segs = skb_mac_gso_segment(skb, features); - if (unlikely(skb_needs_check(skb, tx_path))) + if (unlikely(skb_needs_check(skb, tx_path) && !IS_ERR(segs))) skb_warn_bad_offload(skb); return segs; -- 2.15.1.424.g9478a66081-goog