On 3/6/26 00:30, Michal Luczaj wrote:
> 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 <[email protected]>
> Suggested-by: Martin KaFai Lau <[email protected]>
> Signed-off-by: Michal Luczaj <[email protected]>
> ---
> 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
...
> @@ -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;
>
Another reason to (conditionally) take unix_state_lock() at
sock_map_update_elem{,_sys}(): chunk above can be dropped.
