From: David Ahern <dsahern@gmail.com>
Date: Sun, 3 Dec 2017 17:33:00 +0000 (-0800)
Subject: tcp: use IPCB instead of TCP_SKB_CB in inet_exact_dif_match()
X-Git-Tag: v4.15-rc3~47^2~1^2
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=b4d1605a8ea608fd7dc45b926a05d75d340bde4b;p=linux.git

tcp: use IPCB instead of TCP_SKB_CB in inet_exact_dif_match()

After this fix : ("tcp: add tcp_v4_fill_cb()/tcp_v4_restore_cb()"),
socket lookups happen while skb->cb[] has not been mangled yet by TCP.

Fixes: a04a480d4392 ("net: Require exact match for TCP socket lookups if dif is l3mdev")
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 4e09398009c1..6998707e81f3 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -844,12 +844,11 @@ static inline int tcp_v6_sdif(const struct sk_buff *skb)
 }
 #endif
 
-/* TCP_SKB_CB reference means this can not be used from early demux */
 static inline bool inet_exact_dif_match(struct net *net, struct sk_buff *skb)
 {
 #if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
 	if (!net->ipv4.sysctl_tcp_l3mdev_accept &&
-	    skb && ipv4_l3mdev_skb(TCP_SKB_CB(skb)->header.h4.flags))
+	    skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
 		return true;
 #endif
 	return false;