bpf: sk_msg, fix socket data_ready events

When a skb verdict program is in-use and either another BPF program redirects to that socket or the new SK_PASS support is used the data_ready callback does not wake up application. Instead because the stream parser/verdict is using the sk data_ready callback we wake up the stream parser/verdict block. Fix this by adding a helper to check if the stream parser block is enabled on the sk and if so call the saved pointer which is the upper layers wake up function. This fixes application stalls observed when an application is waiting for data in a blocking read(). Fixes: d829e9c ("tls: convert to generic sk_msg interface") Signed-off-by: John Fastabend <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]>
jbg · Dec 20, 2018 · 552de91 · 552de91
1 parent 5119940
commit 552de91
Show file tree

Hide file tree

Showing 3 changed files with 12 additions and 4 deletions.
diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
@@ -417,6 +417,14 @@ static inline void sk_psock_put(struct sock *sk, struct sk_psock *psock)
 		sk_psock_drop(sk, psock);
 }
 
+static inline void sk_psock_data_ready(struct sock *sk, struct sk_psock *psock)
+{
+	if (psock->parser.enabled)
+		psock->parser.saved_data_ready(sk);
+	else
+		sk->sk_data_ready(sk);
+}
+
 static inline void psock_set_prog(struct bpf_prog **pprog,
 				  struct bpf_prog *prog)
 {

diff --git a/net/core/skmsg.c b/net/core/skmsg.c
@@ -403,7 +403,7 @@ static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
 	msg->skb = skb;
 
 	sk_psock_queue_msg(psock, msg);
-	sk->sk_data_ready(sk);
+	sk_psock_data_ready(sk, psock);
 	return copied;
 }
 
@@ -751,7 +751,7 @@ static int sk_psock_strp_parse(struct strparser *strp, struct sk_buff *skb)
 }
 
 /* Called with socket lock held. */
-static void sk_psock_data_ready(struct sock *sk)
+static void sk_psock_strp_data_ready(struct sock *sk)
 {
 	struct sk_psock *psock;
 
@@ -799,7 +799,7 @@ void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)
 		return;
 
 	parser->saved_data_ready = sk->sk_data_ready;
-	sk->sk_data_ready = sk_psock_data_ready;
+	sk->sk_data_ready = sk_psock_strp_data_ready;
 	sk->sk_write_space = sk_psock_write_space;
 	parser->enabled = true;
 }

diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
@@ -198,7 +198,7 @@ static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
 		msg->sg.start = i;
 		msg->sg.size -= apply_bytes;
 		sk_psock_queue_msg(psock, tmp);
-		sk->sk_data_ready(sk);
+		sk_psock_data_ready(sk, psock);
 	} else {
 		sk_msg_free(sk, tmp);
 		kfree(tmp);