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=1792689103; b=MSWafgXhSv8xGW8m1Oxiu0I5P9R9u/KCDk1kQc6Px0rS48WTqNsizhFLpkDXhL45DZ1g lkM42KjYfJyQZtcWvJ6RVWzKD6gA/QcWhukzupaHgrMHhJLUbZ0ByG6sr98BLi76GmXUn 1jGqtySrm5oTFTFrR7YVx4IsjdTyF58v4PZ2x2xqFgQdZY8qv/gZR6S3hZjgEshfLlXMw uFuVeDiKLjnyOGLe3BX0Cc5rofkaOI6VI5Qv1wizxNIsWIbZCfY82vmFnjPGHwa6aahRS V9hPrmP5ynhOo1SCSm6ZwDzar/BRW3xD5R5bHNzNRISBaBwUI2txysQL47v33/wapHQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792689103; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=Xzcs4Is05M4RgjUyVw2eCgUKNMuM+8vsPDL9M5kZvM8=; b=HluFqxrSNu7okgvI003qznm7VHkQRmZ2jER6Eqy/o+TAk111ZT6g4T9jMjS6KUDeVNhT HlKzL/UwtommailSh1QshTadkY8B6krPWo6l/DWyMwjc+F72154LajK8nQsa6ZAFM7yS4 WaWg+4uVSrLLrvzho7mBCyv7NLTRIXiGI9HeImqef/xz4XrcaziIFrGxFx19P91wwGby5 DULMs6N7xPzkm4Sd/csAzlI6455okJ78xgopAr94AEsQseRFuWXUoF3B/B1neybCTF6Su dAz1PSJB27ZGe03IOqv+AU6GjXjwjMAtvboJbs8Id9DOmFMNvcW6bRs/dnnTmIcrihA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=cOW078k7; 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 33095606A319 for ; Thu, 22 Oct 2026 17:11:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=cOW078k7 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1523C1F01828; Thu, 22 Oct 2026 17:11:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792689102; bh=Xzcs4Is05M4RgjUyVw2eCgUKNMuM+8vsPDL9M5kZvM8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cOW078k7UMYAExs5Y+Mow8zDtWrqngCJNaFOPj3ojHHNldCq+jLLTATTkaK6yL5Vi r2fA1NAwkAyYItb4kDqPRXw5H3YperNEQseUWwZAkdegUMtmUVbWPUcdDvfY2ekKSo HEM5d1nr1kvl+p+FWUyzv9fiDgzwYCRRat8twSG5TvQRU3hPAZe1zeh5KoD3HeKUFp JmvFlZFdfBi/3BoQ4ER4P/aVbm1nV+YmtGOntb+XGnTRw3gQ4SkMOceGdHjgbPOglj 7rJcYCpfNccay+xa0ACKcpLIKoXTfw4Nuc5ZdAWX6H3eoURcCbAX7/OCEbGQRwzNmP +nIS9XY+0TmQw== From: Sasha Levin To: stable@vger.kernel.org Cc: Daehyeon Ko <4ncienth@gmail.com>, Stefano Garzarella , Bobby Eshleman , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12.y 2/2] vsock/virtio: validate packet source for connected sockets Date: Thu, 22 Oct 2026 13:11:39 -0400 Message-ID: <20261022170952.1760451-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261022170952.1760451-1-sashal@kernel.org> References: <2026102110-finalize-subpar-d30e@gregkh> <20261022170952.1760451-1-sashal@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 socket lookup and reset helpers without network namespace parameters ] Signed-off-by: Sasha Levin --- 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(-) diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h index 70302c92d329f..20bbe02d2cfc5 100644 --- a/include/net/af_vsock.h +++ b/include/net/af_vsock.h @@ -216,6 +216,9 @@ void vsock_remove_connected(struct vsock_sock *vsk); 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)); diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index 228e45bf2d769..999cccb323f79 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -335,6 +335,38 @@ struct sock *vsock_find_connected_socket(struct sockaddr_vm *src, } 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. */ diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index 75df280bcc81f..cf7f3dcc075c7 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -1837,7 +1837,8 @@ void virtio_transport_recv_pkt(struct virtio_transport *t, * 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); -- 2.53.0