From nobody Tue Dec 2 02:18:59 2025 Received: from mailtransmit04.runbox.com (mailtransmit04.runbox.com [185.226.149.37]) (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 5959A2FB0BD; Wed, 19 Nov 2025 14:04:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.226.149.37 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763561069; cv=none; b=Yt8MBNeqtKmnvyk4PnavGzvB0M7OWnPwnFRgLf7VN6AILY9hF8q4xEFWTMDFOFUwhChwkLKwu8SDOAAdWfW4K/a/It+RPRCYcQjfhNh7sQCZvM1moI5DDvYCTZDPxdeSJOrbqy07mIEz9KTh6494Y57baV3JsMezY8JOY9xRzvQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763561069; c=relaxed/simple; bh=/+BPYtNUG5Xu5+ISDv/HUJHRqC36BinwRESOVXe6Aa4=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=JQTev5lZI/NlOgcS1oHVDgL5/JWPowPVwP9UMJWMp/M0kTBt02yw1sbsFy3M71bjGkfAsJd73WnUVFvITVPalhMSz8wKlNry84E3b2YWb4eDbNrXpNgzi7gVSEsynN5xRP9HZ/qDfbBE1HTZNv/qjBafizDgnZvpuYu1cwgHdM8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rbox.co; spf=pass smtp.mailfrom=rbox.co; dkim=pass (2048-bit key) header.d=rbox.co header.i=@rbox.co header.b=xco3s39q; arc=none smtp.client-ip=185.226.149.37 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=rbox.co Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=rbox.co Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=rbox.co header.i=@rbox.co header.b="xco3s39q" Received: from mailtransmit03.runbox ([10.9.9.163] helo=aibo.runbox.com) by mailtransmit04.runbox.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1vLinA-005mv9-3g; Wed, 19 Nov 2025 15:04:16 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=rbox.co; s=selector1; h=Cc:To:Message-Id:Content-Transfer-Encoding:Content-Type: MIME-Version:Subject:Date:From; bh=LL1kx54MTYNXzaYfz6YCwaEQd6cdxw7HMjZNJrr5nf0=; b=xco3s39qM71PqlAo+Xqb/nar0N kToWfsOyzPkN62CvWVnE4HN+owlB8sFFFl/jnYaEXKBpAY380ZU+HzbEOV7QH2lCVjtrRAIWBLOFA smJ2I5h4KFG1gVqHoic+8jnHw0xFQkH90+j65LrGJcY/xmRxECj1utt/T5HFgcDRxdEid8tfjmJzp 4KragQmk8IoFCu1Z1IrkZ+KeUBL9h5mf9gU0IFvZ0YFoGS37WGDTdfHN9t9DF6ZjulXRqR17L9CaC 10d74XSAxNMvhyvFrzsehI0kyjerH3Q7vXJo9AEQ32COCfT2bncGMs6x49yiiyR2aQqBXv5l/XWF4 O7RNb1cg==; Received: from [10.9.9.73] (helo=submission02.runbox) by mailtransmit03.runbox with esmtp (Exim 4.86_2) (envelope-from ) id 1vLin9-0000kv-3C; Wed, 19 Nov 2025 15:04:15 +0100 Received: by submission02.runbox with esmtpsa [Authenticated ID (604044)] (TLS1.2:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) id 1vLim2-00FgY3-Qx; Wed, 19 Nov 2025 15:03:06 +0100 From: Michal Luczaj Date: Wed, 19 Nov 2025 15:02:59 +0100 Subject: [PATCH net v2] vsock: Ignore signal/timeout on connect() if already established Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20251119-vsock-interrupted-connect-v2-1-70734cf1233f@rbox.co> X-B4-Tracking: v=1; b=H4sIABLOHWkC/32NQQrCMBBFr1Jm7UgmWmpdeQ/pop1MbBASSWKol N7d2AO4fP/z318hSXSS4NqsEKW45IKvoA8N8Dz6h6AzlUEr3aoLtVhS4Cc6nyXG9yuLQQ7eC2e 0vTZ2bNVZs4G6f0Wxbtndd/CSYajh7FIO8bP/Fdqrn5qIuj/qQkg4sdIkver4ZG9xCsuRAwzbt n0BrRB3kMUAAAA= X-Change-ID: 20250815-vsock-interrupted-connect-f92dfa5042cd To: Stefano Garzarella , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , George Zhang , Andy King , Dmitry Torokhov Cc: virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Michal Luczaj X-Mailer: b4 0.14.3 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@rb= ox.co/ [2]: https://lore.kernel.org/netdev/20250317-vsock-trans-signal-race-v4-0-f= c8837f3f1d4@rbox.co/ [3]: https://lore.kernel.org/netdev/60f1b7db-3099-4f6a-875e-af9f6ef194f6@rb= ox.co/ Fixes: d021c344051a ("VSOCK: Introduce VM Sockets") Signed-off-by: Michal Luczaj Reviewed-by: Stefano Garzarella --- Changes in v2: - Keep changes to minimum, fold in vsock_reset_interrupted() [Stefano] - Link to v1: https://lore.kernel.org/r/20251117-vsock-interrupted-connect-= v1-1-bc021e907c3f@rbox.co --- 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 76763247a377..a9ca9c3b87b3 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -1661,18 +1661,40 @@ static int vsock_connect(struct socket *sock, struc= t sockaddr *addr, timeout =3D schedule_timeout(timeout); lock_sock(sk); =20 - if (signal_pending(current)) { - err =3D sock_intr_errno(timeout); - sk->sk_state =3D sk->sk_state =3D=3D TCP_ESTABLISHED ? TCP_CLOSING : TC= P_CLOSE; - sock->state =3D SS_UNCONNECTED; - vsock_transport_cancel_pkt(vsk); - vsock_remove_connected(vsk); - goto out_wait; - } else if ((sk->sk_state !=3D TCP_ESTABLISHED) && (timeout =3D=3D 0)) { - err =3D -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 =3D=3D 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 !=3D TCP_ESTABLISHED implies that socket is not on + * vsock_connected_table. We keep the binding and the transport + * assigned. + */ + if (signal_pending(current) || timeout =3D=3D 0) { + err =3D timeout =3D=3D 0 ? -ETIMEDOUT : sock_intr_errno(timeout); + + /* Listener might have already responded with + * VIRTIO_VSOCK_OP_RESPONSE. Its handling expects our + * sk_state =3D=3D TCP_SYN_SENT, which hereby we break. + * In such case VIRTIO_VSOCK_OP_RST will follow. + */ sk->sk_state =3D TCP_CLOSE; sock->state =3D SS_UNCONNECTED; + + /* Try to cancel VIRTIO_VSOCK_OP_REQUEST skb sent out by + * transport->connect(). + */ vsock_transport_cancel_pkt(vsk); + goto out_wait; } =20 --- base-commit: 106a67494c53c56f55a2bd0757be0edb6eaa5407 change-id: 20250815-vsock-interrupted-connect-f92dfa5042cd Best regards, --=20 Michal Luczaj