[net] udpv6: Fix the checksum computation when HW checksum does not apply

Message ID 1505352651-14828-1-git-send-email-subashab@codeaurora.org
State Accepted
Delegated to: David Miller
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Series
  • [net] udpv6: Fix the checksum computation when HW checksum does not apply
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Commit Message

Subash Abhinov Kasiviswanathan Sept. 14, 2017, 1:30 a.m.
While trying an ESP transport mode encryption for UDPv6 packets of
datagram size 1436 with MTU 1500, checksum error was observed in
the secondary fragment.

This error occurs due to the UDP payload checksum being missed out
when computing the full checksum for these packets in
udp6_hwcsum_outgoing().

Fixes: d39d938c8228 ("ipv6: Introduce udpv6_send_skb()")
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
---
 net/ipv6/udp.c | 1 +
 1 file changed, 1 insertion(+)

Comments

David Miller Sept. 18, 2017, 6:43 p.m. | #1
From: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Date: Wed, 13 Sep 2017 19:30:51 -0600

> While trying an ESP transport mode encryption for UDPv6 packets of
> datagram size 1436 with MTU 1500, checksum error was observed in
> the secondary fragment.
> 
> This error occurs due to the UDP payload checksum being missed out
> when computing the full checksum for these packets in
> udp6_hwcsum_outgoing().
> 
> Fixes: d39d938c8228 ("ipv6: Introduce udpv6_send_skb()")
> Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>

Good catch, applied and queued up for -stable.

Patch

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index e2ecfb1..40d7234 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1015,6 +1015,7 @@  static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
 		 */
 		offset = skb_transport_offset(skb);
 		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
+		csum = skb->csum;
 
 		skb->ip_summed = CHECKSUM_NONE;