From 701ba0df95205187f1afc4f3f520bff57ba4001d Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Tue, 12 Dec 2017 11:39:04 -0500 Subject: [PATCH] net: avoid skb_warn_bad_offload on IS_ERR commit 8d74e9f88d65af8bb2e095aff506aa6eac755ada upstream. 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- 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 ffee085f0357..d33bbed640b1 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2792,7 +2792,7 @@ 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; -- 2.20.1