Commit 8a0d57df authored May 24, 2023 by Jakub Kicinski Committed by David S. Miller May 26, 2023

tls: improve lockless access safety of tls_err_abort()



Most protos' poll() methods insert a memory barrier between
writes to sk_err and sk_error_report(). This dates back to
commit a4d25803 ("tcp: Fix race in tcp_poll").

I guess we should do the same thing in TLS, tcp_poll() does
not hold the socket lock.

Fixes: 3c4d7559 ("tls: kernel TLS support")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent aa866ee4

net/tls/tls_strp.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -20,7 +20,9 @@ static void tls_strp_abort_strp(struct tls_strparser *strp, int err)
		strp->stopped = 1;

		/* Report an error on the lower socket */
		strp->sk->sk_err = -err;
		WRITE_ONCE(strp->sk->sk_err, -err);
		/* Paired with smp_rmb() in tcp_poll() */
		smp_wmb();
		sk_error_report(strp->sk);
		}

net/tls/tls_sw.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -70,7 +70,9 @@ noinline void tls_err_abort(struct sock *sk, int err)
		{
		WARN_ON_ONCE(err >= 0);
		/* sk->sk_err should contain a positive error code. */
		sk->sk_err = -err;
		WRITE_ONCE(sk->sk_err, -err);
		/* Paired with smp_rmb() in tcp_poll() */
		smp_wmb();
		sk_error_report(sk);
		}