From: Eric Dumazet <edumazet@xxxxxxxxxx> 3.12-stable review patch. If anyone has any objections, please let me know. =============== [ Upstream commit 4f2e4ad56a65f3b7d64c258e373cb71e8d2499f4 ] Sending zero checksum is ok for TCP, but not for UDP. UDPv6 receiver should by default drop a frame with a 0 checksum, and UDPv4 would not verify the checksum and might accept a corrupted packet. Simply replace such checksum by 0xffff, regardless of transport. This error was caught on SIT tunnels, but seems generic. Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Cc: Maciej Żenczykowski <maze@xxxxxxxxxx> Cc: Willem de Bruijn <willemb@xxxxxxxxxx> Acked-by: Maciej Żenczykowski <maze@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- 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 b3788eb33ce4..80468a34ef12 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2263,7 +2263,7 @@ int skb_checksum_help(struct sk_buff *skb) goto out; } - *(__sum16 *)(skb->data + offset) = csum_fold(csum); + *(__sum16 *)(skb->data + offset) = csum_fold(csum) ?: CSUM_MANGLED_0; out_set_summed: skb->ip_summed = CHECKSUM_NONE; out: -- 2.10.2 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html