Patch "net: fix incorrect original ingress device index in PKTINFO" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

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

    net: fix incorrect original ingress device index in PKTINFO

to the 4.9-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:
     net-fix-incorrect-original-ingress-device-index-in-pktinfo.patch
and it can be found in the queue-4.9 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 Thu Jan 12 21:37:26 CET 2017
From: Wei Zhang <asuka.com@163.com>
Date: Thu, 29 Dec 2016 16:45:04 +0800
Subject: net: fix incorrect original ingress device index in PKTINFO

From: Wei Zhang <asuka.com@163.com>


[ Upstream commit f0c16ba8933ed217c2688b277410b2a37ba81591 ]

When we send a packet for our own local address on a non-loopback
interface (e.g. eth0), due to the change had been introduced from
commit 0b922b7a829c ("net: original ingress device index in PKTINFO"), the
original ingress device index would be set as the loopback interface.
However, the packet should be considered as if it is being arrived via the
sending interface (eth0), otherwise it would break the expectation of the
userspace application (e.g. the DHCPRELEASE message from dhcp_release
binary would be ignored by the dnsmasq daemon, since it come from lo which
is not the interface dnsmasq bind to)

Fixes: 0b922b7a829c ("net: original ingress device index in PKTINFO")
Acked-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: Wei Zhang <asuka.com@163.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv4/ip_sockglue.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -1202,8 +1202,14 @@ void ipv4_pktinfo_prepare(const struct s
 		 * which has interface index (iif) as the first member of the
 		 * underlying inet{6}_skb_parm struct. This code then overlays
 		 * PKTINFO_SKB_CB and in_pktinfo also has iif as the first
-		 * element so the iif is picked up from the prior IPCB
+		 * element so the iif is picked up from the prior IPCB. If iif
+		 * is the loopback interface, then return the sending interface
+		 * (e.g., process binds socket to eth0 for Tx which is
+		 * redirected to loopback in the rtable/dst).
 		 */
+		if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX)
+			pktinfo->ipi_ifindex = inet_iif(skb);
+
 		pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
 	} else {
 		pktinfo->ipi_ifindex = 0;


Patches currently in stable-queue which might be from asuka.com@163.com are

queue-4.9/net-fix-incorrect-original-ingress-device-index-in-pktinfo.patch