netdev - [PATCH net-next] ipv6: fix NULL deref in ip6_rcv

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Date:   Wed, 13 Apr 2022 13:56:53 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     David Ahern <dsahern@...nel.org>, netdev <netdev@...r.kernel.org>,
        Eric Dumazet <edumazet@...gle.com>,
        Eric Dumazet <eric.dumazet@...il.com>,
        Menglong Dong <imagedong@...cent.com>,
        Jiang Biao <benbjiang@...cent.com>,
        Hao Peng <flyingpeng@...cent.com>
Subject: [PATCH net-next] ipv6: fix NULL deref in ip6_rcv_core()

From: Eric Dumazet <edumazet@...gle.com>

idev can be NULL, as the surrounding code suggests.

Fixes: 4daf841a2ef3 ("net: ipv6: add skb drop reasons to ip6_rcv_core()")
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Cc: Menglong Dong <imagedong@...cent.com>
Cc: Jiang Biao <benbjiang@...cent.com>
Cc: Hao Peng <flyingpeng@...cent.com>
---
 net/ipv6/ip6_input.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 126ae3aa67e1dc579bc0eecd21416e9d89dcbf08..0322cc86b84eaaed7529a4b65fdfba4c97a38375 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -166,7 +166,7 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev,
 	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||
 	    !idev || unlikely(idev->cnf.disable_ipv6)) {
 		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);
-		if (unlikely(idev->cnf.disable_ipv6))
+		if (idev && unlikely(idev->cnf.disable_ipv6))
 			SKB_DR_SET(reason, IPV6DISABLED);
 		goto drop;
 	}
-- 
2.35.1.1178.g4f1659d476-goog