From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792774335; b=282vV/jdS8IBEZtCEOrgPfcWZ5v/z6jVn4wO/QOKKfC5k8UFjom6mJL+eN0wuqEV0oBm KwlEL+cO2jF7pM4VsqFPp8fpC0//CT9yYTG5pIiHACELx1jl5TpLa10gP0kIVeVGJUywd eWf16Rukx0J+OottAa8BBeWcUc16dnv33pdhX43dSJDjB7YKlHToCw1cpuu0eXIMCCmhk w8aeIjtlu2/NMgfL6TOcmxYpAx8Sp59QKo2SJJ2vmZg3Y83k273we2bXzgKeyQ0P+jh6a ECBGJ/wxtsbFO/ZnCqHVeZMdI4joYetKMXUvZuHT42nz+7X9UYQi6BdjKxBvWX02oZA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792774335; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=7jR6woQC/xsn5nze7p/QqDsk9CbTe2gOxLLBvdI11bQ=; b=bpfT65UiWNOJd1c0ax4tzSOTEIChuKJmIciLE9C2rC4k4tcrZdeAMvkFw0rTp1y7iLr/ 2vQb6KXJPy7JL92X0ez8AcCUHDm9PO1VvgTM4jyDU9Nu7Sf00vorratbZ0Nzz1muJHO8V sX99+FCnVYZ6k7ULpiU85EJ7VLGtbGplf9O2Pcsg0bH1UFi3dNufzLeiq76TbKs8ItNVJ W8SRP0MsHv9QLzYRgIfEFtZzjc4oNHE+r38+NBNzpOpNsxGm8VAfC0ElUG9KFoeZ8hU7l iRa7KK8yfptloI+ZNYPyxFoalQHsPDU5mPj0nxLkpGK9rI4EOeSZ5PzFAUTwf7dYD+A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=gFoEMpD+; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6501C606A31A; Fri, 23 Oct 2026 16:52:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=gFoEMpD+ Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3BF71F01825; Fri, 23 Oct 2026 16:52:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792774335; bh=7jR6woQC/xsn5nze7p/QqDsk9CbTe2gOxLLBvdI11bQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gFoEMpD+gm6BlvmW9p2X+b1SbfUiGVCMAa0dy52I2DbyF5DKLrlEVkxXHKEw6OkMl pAyaV5OXye/AW+hUn13btPhysytPoZb4fkaHh0KaxfkzpqBQcyTS9FYL4Uen5Xh1K7 2T71NrXrTKOjgPIwi49xzDOog/j0amjWe4NAgarU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Stefano Garzarella , Bobby Eshleman , Daehyeon Ko <4ncienth@gmail.com>, Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18 184/193] vsock/virtio: validate packet source for connected sockets Date: Fri, 23 Oct 2026 18:37:41 +0200 Message-ID: <20261023163718.574659356@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261023163714.201276352@linuxfoundation.org> References: <20261023163714.201276352@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daehyeon Ko <4ncienth@gmail.com> [ Upstream commit dee44f41f206becb41c492899c1996cfd7f82a1b ] virtio_transport_recv_pkt() looks up sockets first by the full source and destination tuple, then by destination only in the bound table. The fallback is needed for listening and connecting sockets, but sockets remain in the bound table after connect(), so it can also return a non-listening socket. The fallback does not validate the source address. In TCP_SYN_SENT, a RESPONSE from an unrelated source can transition the victim socket to TCP_ESTABLISHED while its stored remote address remains unchanged. Subsequent RW packets from that source are delivered through the same destination-only fallback. This was reproduced with capability-empty processes under different UIDs. The attacker discovered the target tuple through unprivileged AF_VSOCK sock_diag and caused the victim socket to read 16 attacker-chosen bytes; the intended peer-side socket read 0 of those 16 bytes. Add vsock_check_source() to validate the transport, source port and source CID against the peer stored in a non-listening socket. The local transport is the CID exception because its packets are generated internally with VMADDR_CID_LOCAL as their source, including connections using CID aliases. Use the helper after lock_sock() in the virtio receive path. Fixes: 06a8fc78367d ("VSOCK: Introduce virtio_vsock_common.ko") Closes: https://lore.kernel.org/netdev/20260813121236.2328599-1-4ncienth@gmail.com/ Cc: stable@vger.kernel.org Suggested-by: Stefano Garzarella Reviewed-by: Bobby Eshleman Signed-off-by: Daehyeon Ko <4ncienth@gmail.com> Link: https://patch.msgid.link/20260826003929.966160-2-4ncienth@gmail.com Signed-off-by: Jakub Kicinski [ sashal: Adjusted context for existing vsock APIs without network-namespace support. ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- include/net/af_vsock.h | 3 +++ net/vmw_vsock/af_vsock.c | 32 ++++++++++++++++++++++++++++++++ net/vmw_vsock/virtio_transport_common.c | 3 ++- 3 files changed, 37 insertions(+), 1 deletion(-) --- a/include/net/af_vsock.h +++ b/include/net/af_vsock.h @@ -216,6 +216,9 @@ void vsock_remove_connected(struct vsock struct sock *vsock_find_bound_socket(struct sockaddr_vm *addr); struct sock *vsock_find_connected_socket(struct sockaddr_vm *src, struct sockaddr_vm *dst); +bool vsock_check_source(const struct vsock_sock *vsk, + const struct vsock_transport *transport, + const struct sockaddr_vm *src); void vsock_remove_sock(struct vsock_sock *vsk); void vsock_for_each_connected_socket(struct vsock_transport *transport, void (*fn)(struct sock *sk)); --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -335,6 +335,38 @@ struct sock *vsock_find_connected_socket } EXPORT_SYMBOL_GPL(vsock_find_connected_socket); +/** + * vsock_check_source - validate a packet source against a socket peer + * @vsk: socket receiving the packet + * @transport: transport receiving the packet + * @src: source address from the packet + * + * Return: true if the packet arrived on the socket's assigned transport and + * its source matches the stored peer. Loopback packets are generated + * internally and always use the local CID as their source, including + * connections using a valid CID alias. + * + * The caller must hold the socket lock and must not call this for listening + * sockets, which accept packets from any source and have no assigned + * transport. + */ +bool vsock_check_source(const struct vsock_sock *vsk, + const struct vsock_transport *transport, + const struct sockaddr_vm *src) +{ + if (vsk->transport != transport) + return false; + + if (src->svm_port != vsk->remote_addr.svm_port) + return false; + + if (src->svm_cid == vsk->remote_addr.svm_cid) + return true; + + return transport->get_local_cid() == VMADDR_CID_LOCAL; +} +EXPORT_SYMBOL_GPL(vsock_check_source); + void vsock_remove_sock(struct vsock_sock *vsk) { /* Transport reassignment must not remove the binding. */ --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -1819,7 +1819,8 @@ void virtio_transport_recv_pkt(struct vi * lock_sock (note: listener sockets are not assigned to any transport) */ if (sock_flag(sk, SOCK_DONE) || - (sk->sk_state != TCP_LISTEN && vsk->transport != &t->transport)) { + (sk->sk_state != TCP_LISTEN && + !vsock_check_source(vsk, &t->transport, &src))) { (void)virtio_transport_reset_no_sock(t, skb); release_sock(sk); sock_put(sk);