Patch "udp6: fix UDP/IPv6 encap resubmit path" has been added to the 4.4-stable tree

Patch "udp6: fix UDP/IPv6 encap resubmit path" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    udp6: fix UDP/IPv6 encap resubmit path

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     udp6-fix-udp-ipv6-encap-resubmit-path.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Sat Apr 16 10:02:53 PDT 2016
From: Bill Sommerfeld <wsommerfeld@google.com>
Date: Fri, 4 Mar 2016 14:47:21 -0800
Subject: udp6: fix UDP/IPv6 encap resubmit path

From: Bill Sommerfeld <wsommerfeld@google.com>

[ Upstream commit 59dca1d8a6725a121dae6c452de0b2611d5865dc ]

IPv4 interprets a negative return value from a protocol handler as a
request to redispatch to a new protocol.  In contrast, IPv6 interprets a
negative value as an error, and interprets a positive value as a request
for redispatch.

UDP for IPv6 was unaware of this difference.  Change __udp6_lib_rcv() to
return a positive value for redispatch.  Note that the socket's
encap_rcv hook still needs to return a negative value to request
dispatch, and in the case of IPv6 packets, adjust IP6CB(skb)->nhoff to
identify the byte containing the next protocol.

Signed-off-by: Bill Sommerfeld <wsommerfeld@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv6/udp.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -916,11 +916,9 @@ int __udp6_lib_rcv(struct sk_buff *skb,
 		ret = udpv6_queue_rcv_skb(sk, skb);
 		sock_put(sk);
 
-		/* a return value > 0 means to resubmit the input, but
-		 * it wants the return to be -protocol, or 0
-		 */
+		/* a return value > 0 means to resubmit the input */
 		if (ret > 0)
-			return -ret;
+			return ret;
 
 		return 0;
 	}


Patches currently in stable-queue which might be from wsommerfeld@google.com are

queue-4.4/udp6-fix-udp-ipv6-encap-resubmit-path.patch