[PATCH bpf v3 1/5] bpf, sockmap: Annotate af_unix sock::sk_state data-races

[Michal Luczaj]

sock_map_sk_state_allowed() and sock_map_redirect_allowed() read af_unix
socket sk_state locklessly.

Use READ_ONCE(). Note that for sock_map_redirect_allowed() change affects
not only af_unix, but all non-TCP sockets (UDP, af_vsock).

Suggested-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Suggested-by: Martin KaFai Lau <martin.lau@xxxxxxxxx>
Signed-off-by: Michal Luczaj <mhal@xxxxxxx>
---
 net/core/sock_map.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index b0e96337a269..02a68be3002a 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -530,7 +530,7 @@ static bool sock_map_redirect_allowed(const struct sock *sk)
 	if (sk_is_tcp(sk))
 		return sk->sk_state != TCP_LISTEN;
 	else
-		return sk->sk_state == TCP_ESTABLISHED;
+		return READ_ONCE(sk->sk_state) == TCP_ESTABLISHED;
 }
 
 static bool sock_map_sk_is_suitable(const struct sock *sk)
@@ -543,7 +543,7 @@ static bool sock_map_sk_state_allowed(const struct sock *sk)
 	if (sk_is_tcp(sk))
 		return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_LISTEN);
 	if (sk_is_stream_unix(sk))
-		return (1 << sk->sk_state) & TCPF_ESTABLISHED;
+		return (1 << READ_ONCE(sk->sk_state)) & TCPF_ESTABLISHED;
 	if (sk_is_vsock(sk) &&
 	    (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET))
 		return (1 << sk->sk_state) & TCPF_ESTABLISHED;

-- 
2.52.0