From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Date: Fri, 8 Apr 2022 14:03:42 +0000 (+0200)
Subject: ipv6: fix panic when forwarding a pkt with no in6 dev
X-Git-Tag: v4.19.239~4
X-Git-Url: https://git.fsl.cs.sunysb.edu/?a=commitdiff_plain;h=74b68f5249f16c5f7f675d0f604fa6ae20e3a151;p=wrapfs-2.6.37.y.git

ipv6: fix panic when forwarding a pkt with no in6 dev

commit e3fa461d8b0e185b7da8a101fe94dfe6dd500ac0 upstream.

kongweibin reported a kernel panic in ip6_forward() when input interface
has no in6 dev associated.

The following tc commands were used to reproduce this panic:
tc qdisc del dev vxlan100 root
tc qdisc add dev vxlan100 root netem corrupt 5%

CC: stable@vger.kernel.org
Fixes: ccd27f05ae7b ("ipv6: fix 'disable_policy' for fwd packets")
Reported-by: kongweibin <kongweibin2@huawei.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 373df391dc93..6fd1a4b61747 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -460,7 +460,7 @@ int ip6_forward(struct sk_buff *skb)
 		goto drop;
 
 	if (!net->ipv6.devconf_all->disable_policy &&
-	    !idev->cnf.disable_policy &&
+	    (!idev || !idev->cnf.disable_policy) &&
 	    !xfrm6_policy_check(NULL, XFRM_POLICY_FWD, skb)) {
 		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
 		goto drop;