From: Eric Dumazet <eduma...@google.com>
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 <eduma...@google.com>
Cc: Maciej Żenczykowski <m...@google.com>
Cc: Willem de Bruijn <will...@google.com>
Acked-by: Maciej Żenczykowski <m...@google.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Jiri Slaby <jsl...@suse.cz>
---
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
