diff mbox series

[net-next] net: avoid skb_warn_bad_offload on IS_ERR

Message ID 20171212163904.209480-1-willemdebruijn.kernel@gmail.com
State Accepted, archived
Delegated to: David Miller
Headers show
Series [net-next] net: avoid skb_warn_bad_offload on IS_ERR | expand

Commit Message

Willem de Bruijn Dec. 12, 2017, 4:39 p.m. UTC 
From: Willem de Bruijn <willemb@google.com>

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 <willemb@google.com>
---
 net/core/dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

David Miller Dec. 13, 2017, 8:14 p.m. UTC | #1 
From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date: Tue, 12 Dec 2017 11:39:04 -0500

> From: Willem de Bruijn <willemb@google.com>
> 
> 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 <willemb@google.com>

Applied, thanks Willem.
diff mbox series

Patch

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;