[PATCH 3.13.y-ckt 121/138] ipv6/udp: use sticky pktinfo egress ifindex on connect()

From: Kamal Mostafa
Date: Wed Mar 09 2016 - 18:20:58 EST

3.13.11-ckt36 -stable review patch. If anyone has any objections, please let me know.


From: Paolo Abeni <pabeni@xxxxxxxxxx>

commit 1cdda91871470f15e79375991bd2eddc6e86ddb1 upstream.

Currently, the egress interface index specified via IPV6_PKTINFO
is ignored by __ip6_datagram_connect(), so that RFC 3542 section 6.7
can be subverted when the user space application calls connect()
before sendmsg().
Fix it by initializing properly flowi6_oif in connect() before
performing the route lookup.

Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Acked-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
net/ipv6/datagram.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
index 6e85cb9..28be769 100644
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -162,6 +162,9 @@ ipv4_connected:
fl6.fl6_dport = inet->inet_dport;
fl6.fl6_sport = inet->inet_sport;

+ if (!fl6.flowi6_oif)
+ fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
if (!fl6.flowi6_oif && (addr_type&IPV6_ADDR_MULTICAST))
fl6.flowi6_oif = np->mcast_oif;