From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2B8A5334366; Thu, 27 Nov 2025 14:55:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764255315; cv=none; b=qMuhNffui5la7Qg9vnV0n9jbdsGXCvcP0vlFmf15LdwWxEbCg76SRXuuCapEIXee08LWjv6IucS5Fxa5hyMiRPeqbBhQ/bi9rZHn22FZ6iyI3u6c2zkLBrKHVP/jec8qG0nXaaO3CaP0cDvy0h6BcJ8wHrXCsrKbWvRcrgzo/rw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764255315; c=relaxed/simple; bh=sCR0I3HWYvW3rSMgsGNqK9N5euQTGj8Gljz+KO4fhJ0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kGcqvwxgtXtPnhZyrB6FiAT+3d+rtj8jMJNewS0rgExHjGj11WvSDW82kfyDfw6LtermGXnLwhsltIkACXdMA5f40DZq7ZQifsIdN3BCxMzPniXm2R4BPry+BdiPpKFnER/hwM+nhmsiBrK6di/oZuQI3d0LErbqTxsCp5N+KMM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=I+H1CTpD; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="I+H1CTpD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9EB2CC4CEF8; Thu, 27 Nov 2025 14:55:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1764255315; bh=sCR0I3HWYvW3rSMgsGNqK9N5euQTGj8Gljz+KO4fhJ0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=I+H1CTpDwfhRn/3Mze0rO1Wsmhj+HIzu1RDIRVn+MMYaK82eloxOWk9bom8zelLwh XEbyAORFi8KSz+/ke2pTeA2pY/c6DiZfOGW6TKdU2pfEGst80zjZRSGKvBOcAqVr5J 3OyVN7QdOu967mRUkEqkE+cSHBH6toO8NrcFkd4o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Michal Luczaj , Stefano Garzarella , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12 082/112] vsock: Ignore signal/timeout on connect() if already established Date: Thu, 27 Nov 2025 15:46:24 +0100 Message-ID: <20251127144035.843386660@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251127144032.705323598@linuxfoundation.org> References: <20251127144032.705323598@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Luczaj [ Upstream commit 002541ef650b742a198e4be363881439bb9d86b4 ] During connect(), acting on a signal/timeout by disconnecting an already established socket leads to several issues: 1. connect() invoking vsock_transport_cancel_pkt() -> virtio_transport_purge_skbs() may race with sendmsg() invoking virtio_transport_get_credit(). This results in a permanently elevated `vvs->bytes_unsent`. Which, in turn, confuses the SOCK_LINGER handling. 2. connect() resetting a connected socket's state may race with socket being placed in a sockmap. A disconnected socket remaining in a sockmap breaks sockmap's assumptions. And gives rise to WARNs. 3. connect() transitioning SS_CONNECTED -> SS_UNCONNECTED allows for a transport change/drop after TCP_ESTABLISHED. Which poses a problem for any simultaneous sendmsg() or connect() and may result in a use-after-free/null-ptr-deref. Do not disconnect socket on signal/timeout. Keep the logic for unconnected sockets: they don't linger, can't be placed in a sockmap, are rejected by sendmsg(). [1]: https://lore.kernel.org/netdev/e07fd95c-9a38-4eea-9638-133e38c2ec9b@rbox.co/ [2]: https://lore.kernel.org/netdev/20250317-vsock-trans-signal-race-v4-0-fc8837f3f1d4@rbox.co/ [3]: https://lore.kernel.org/netdev/60f1b7db-3099-4f6a-875e-af9f6ef194f6@rbox.co/ Fixes: d021c344051a ("VSOCK: Introduce VM Sockets") Signed-off-by: Michal Luczaj Reviewed-by: Stefano Garzarella Link: https://patch.msgid.link/20251119-vsock-interrupted-connect-v2-1-70734cf1233f@rbox.co Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/vmw_vsock/af_vsock.c | 40 +++++++++++++++++++++++++++++++--------- 1 file changed, 31 insertions(+), 9 deletions(-) diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index 68a9d4214584f..621be9be64f67 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -1616,18 +1616,40 @@ static int vsock_connect(struct socket *sock, struct sockaddr *addr, timeout = schedule_timeout(timeout); lock_sock(sk); - if (signal_pending(current)) { - err = sock_intr_errno(timeout); - sk->sk_state = sk->sk_state == TCP_ESTABLISHED ? TCP_CLOSING : TCP_CLOSE; - sock->state = SS_UNCONNECTED; - vsock_transport_cancel_pkt(vsk); - vsock_remove_connected(vsk); - goto out_wait; - } else if ((sk->sk_state != TCP_ESTABLISHED) && (timeout == 0)) { - err = -ETIMEDOUT; + /* Connection established. Whatever happens to socket once we + * release it, that's not connect()'s concern. No need to go + * into signal and timeout handling. Call it a day. + * + * Note that allowing to "reset" an already established socket + * here is racy and insecure. + */ + if (sk->sk_state == TCP_ESTABLISHED) + break; + + /* If connection was _not_ established and a signal/timeout came + * to be, we want the socket's state reset. User space may want + * to retry. + * + * sk_state != TCP_ESTABLISHED implies that socket is not on + * vsock_connected_table. We keep the binding and the transport + * assigned. + */ + if (signal_pending(current) || timeout == 0) { + err = timeout == 0 ? -ETIMEDOUT : sock_intr_errno(timeout); + + /* Listener might have already responded with + * VIRTIO_VSOCK_OP_RESPONSE. Its handling expects our + * sk_state == TCP_SYN_SENT, which hereby we break. + * In such case VIRTIO_VSOCK_OP_RST will follow. + */ sk->sk_state = TCP_CLOSE; sock->state = SS_UNCONNECTED; + + /* Try to cancel VIRTIO_VSOCK_OP_REQUEST skb sent out by + * transport->connect(). + */ vsock_transport_cancel_pkt(vsk); + goto out_wait; } -- 2.51.0