Re: [PATCH] net: tls: fix possible race condition between do_tls_getsockopt_conf() and do_tls_setsockopt_conf()

Jakub Kicinski
2023-02-27T19:08:02Z

On Mon, 27 Feb 2023 11:26:18 +0800 Hangyu Hua wrote:
> In order to reduce ambiguity, I think it may be a good idea only to
> lock do_tls_getsockopt_conf() like we did in do_tls_setsockopt()
>
> It will look like:
>
> static int do_tls_getsockopt(struct sock *sk, int optname,
> char __user *optval, int __user *optlen)
> {
> int rc = 0;
>
> switch (optname) {
> case TLS_TX:
> case TLS_RX:
> + lock_sock(sk);
> rc = do_tls_getsockopt_conf(sk, optval, optlen,
> optname == TLS_TX);
> + release_sock(sk);
> break;
> case TLS_TX_ZEROCOPY_RO:
> rc = do_tls_getsockopt_tx_zc(sk, optval, optlen);
> break;
> case TLS_RX_EXPECT_NO_PAD:
> rc = do_tls_getsockopt_no_pad(sk, optval, optlen);
> break;
> default:
> rc = -ENOPROTOOPT;
> break;
> }
> return rc;
> }
>
> Of cause, I will clean the lock in do_tls_getsockopt_conf(). What do you
> guys think?

I'd suggest to take the lock around the entire switch statement.