[074/205] ipv6: fix NULL reference in proxy neighbor discovery

[Greg KH]

2.6.34-stable review patch.  If anyone has any objections, please let us know.

------------------

From: stephen hemminger <shemminger@xxxxxxxxxx>

commit 9f888160bdcccf0565dd2774956b8d9456e610be upstream.

The addition of TLLAO option created a kernel OOPS regression
for the case where neighbor advertisement is being sent via
proxy path.  When using proxy, ipv6_get_ifaddr() returns NULL
causing the NULL dereference.

Change causing the bug was:
commit f7734fdf61ec6bb848e0bafc1fb8bad2c124bb50
Author: Octavian Purdila <opurdila@xxxxxxxxxxx>
Date:   Fri Oct 2 11:39:15 2009 +0000

    make TLLAO option for NA packets configurable

Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxxxx>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@xxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 net/ipv6/ndisc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -586,6 +586,7 @@ static void ndisc_send_na(struct net_dev
 		src_addr = solicited_addr;
 		if (ifp->flags & IFA_F_OPTIMISTIC)
 			override = 0;
+		inc_opt |= ifp->idev->cnf.force_tllao;
 		in6_ifa_put(ifp);
 	} else {
 		if (ipv6_dev_get_saddr(dev_net(dev), dev, daddr,
@@ -599,7 +600,6 @@ static void ndisc_send_na(struct net_dev
 	icmp6h.icmp6_solicited = solicited;
 	icmp6h.icmp6_override = override;
 
-	inc_opt |= ifp->idev->cnf.force_tllao;
 	__ndisc_send(dev, neigh, daddr, src_addr,
 		     &icmp6h, solicited_addr,
 		     inc_opt ? ND_OPT_TARGET_LL_ADDR : 0);


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