From: Eric Dumazet <edumazet@google.com>
Date: Thu, 2 Jun 2016 21:52:43 +0000 (-0700)
Subject: Possible problem with e6afc8ac ("udp: remove headers from UDP packets before queueing")
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ce25d66ad5f8d921bac5fe2d32d62fa30c0f9a70;p=linux-beck.git

Possible problem with e6afc8ac ("udp: remove headers from UDP packets before queueing")

Paul Moore tracked a regression caused by a recent commit, which
mistakenly assumed that sk_filter() could be avoided if socket
had no current BPF filter.

The intent was to avoid udp_lib_checksum_complete() overhead.

But sk_filter() also checks skb_pfmemalloc() and
security_sock_rcv_skb(), so better call it.

Fixes: e6afc8ace6dd ("udp: remove headers from UDP packets before queueing")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Paul Moore <paul@paul-moore.com>
Tested-by: Paul Moore <paul@paul-moore.com>
Tested-by: Stephen Smalley <sds@tycho.nsa.gov>
Cc: samanthakumar <samanthakumar@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index d56c0559b477..0ff31d97d485 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1618,12 +1618,12 @@ int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		}
 	}
 
-	if (rcu_access_pointer(sk->sk_filter)) {
-		if (udp_lib_checksum_complete(skb))
+	if (rcu_access_pointer(sk->sk_filter) &&
+	    udp_lib_checksum_complete(skb))
 			goto csum_error;
-		if (sk_filter(sk, skb))
-			goto drop;
-	}
+
+	if (sk_filter(sk, skb))
+		goto drop;
 
 	udp_csum_pull_header(skb);
 	if (sk_rcvqueues_full(sk, sk->sk_rcvbuf)) {
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 2da1896af934..f421c9f23c5b 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -653,12 +653,12 @@ int udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		}
 	}
 
-	if (rcu_access_pointer(sk->sk_filter)) {
-		if (udp_lib_checksum_complete(skb))
-			goto csum_error;
-		if (sk_filter(sk, skb))
-			goto drop;
-	}
+	if (rcu_access_pointer(sk->sk_filter) &&
+	    udp_lib_checksum_complete(skb))
+		goto csum_error;
+
+	if (sk_filter(sk, skb))
+		goto drop;
 
 	udp_csum_pull_header(skb);
 	if (sk_rcvqueues_full(sk, sk->sk_rcvbuf)) {