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>

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)) {