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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Paul Moore <paul@paul-moore.com>, David Miller <davem@davemloft.net>
Cc: samanthakumar@google.com, linux-security-module@vger.kernel.org,
	selinux@tycho.nsa.gov, netdev@vger.kernel.org,
	Stephen Smalley <sds@tycho.nsa.gov>,
	samanthakumar <samanthakumar@google.com>
Subject: Re: Possible problem with e6afc8ac ("udp: remove headers from UDP packets before queueing")
Date: Thu, 02 Jun 2016 14:52:43 -0700	[thread overview]
Message-ID: <1464904363.5939.185.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <CAHC9VhQAiTRWMN-vNDXgAni2MhsyEYP8f2mZDY63xrx=5SxenQ@mail.gmail.com>

From: Eric Dumazet <edumazet@google.com>

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>
---
 net/ipv4/udp.c |   10 +++++-----
 net/ipv6/udp.c |   12 ++++++------
 2 files changed, 11 insertions(+), 11 deletions(-)

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)) {

  parent reply	other threads:[~2016-06-02 21:52 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-01 19:01 Possible problem with e6afc8ac ("udp: remove headers from UDP packets before queueing") Paul Moore
2016-06-01 19:18 ` Eric Dumazet
     [not found]   ` <1464808695.5939.167.camel-XN9IlZ5yJG9HTL0Zs8A6p+yfmBU6pStAUsxypvmhUTTZJqsBc5GL+g@public.gmane.org>
2016-06-01 20:44     ` Stephen Smalley
2016-06-01 20:44       ` Stephen Smalley
2016-06-02 21:36       ` Paul Moore
2016-06-02 21:44         ` Eric Dumazet
2016-06-02 21:52         ` Eric Dumazet [this message]
2016-06-02 22:31           ` David Miller
2016-06-03  2:58             ` Eric Dumazet
2016-06-03  4:23               ` David Miller

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