This is a note to let you know that I've just added the patch titled
tls: improve lockless access safety of tls_err_abort()
to the 6.3-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tls-improve-lockless-access-safety-of-tls_err_abort.patch
and it can be found in the queue-6.3 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 886c05c76858275a8eb45bd9ddd9114364ceb1d0
Author: Jakub Kicinski <kuba@xxxxxxxxxx>
Date: Wed May 24 22:17:41 2023 -0700
tls: improve lockless access safety of tls_err_abort()
[ Upstream commit 8a0d57df8938e9fd2e99d47a85b7f37d86f91097 ]
Most protos' poll() methods insert a memory barrier between
writes to sk_err and sk_error_report(). This dates back to
commit a4d258036ed9 ("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: 3c4d7559159b ("tls: kernel TLS support")
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/tls/tls_strp.c b/net/tls/tls_strp.c
index da95abbb7ea32..f37f4a0fcd3c2 100644
--- a/net/tls/tls_strp.c
+++ b/net/tls/tls_strp.c
@@ -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);
}
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 6e6a7c37d685c..1a53c8f481e9a 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -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);
}
