From nobody Thu Oct 9 10:38:29 2025 Received: from mailtransmit05.runbox.com (mailtransmit05.runbox.com [185.226.149.38]) (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 66F09285053 for ; Wed, 18 Jun 2025 12:34:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.226.149.38 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750250095; cv=none; b=Wj0XxzQSlyH4w2f5aJM8HubduqVPN5ccgDO+WsZ2lSzAGWWHTsRgloBu58h/0dG/W7aoPWXQsR1KGj/XqUPzjq2obWY6vdSsnrLnm8wFJxavhcSGFR9z4PSQ1bMmBAfYqUFsWa7wXyvnnDOujsp7c0lqKtLbtv8ePyp4KMvMh7o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750250095; c=relaxed/simple; bh=+xdQqkU9neaPKDSewD9n2v8JbhsqM+sf1DMZOvK233o=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=X9wPvaRQfs5J5GoHU7tFds+ho8ESCM8o7cA+OlmGy9H5N/oTkB5EVIDxr2ockrPccO6+oLgJULNra0cmgX/nQUDkKq+gkmOco+a1J6txB3u9clbyeGd2LXpfw9M1Zz0BCpYI+fSXYoKgysYOMKTmopwHm3XAPYKS13jhwtiAOhU= 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=XvAbdhO9; arc=none smtp.client-ip=185.226.149.38 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="XvAbdhO9" Received: from mailtransmit02.runbox ([10.9.9.162] helo=aibo.runbox.com) by mailtransmit05.runbox.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1uRs0B-00CiFK-Bx; Wed, 18 Jun 2025 14:34:51 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=rbox.co; s=selector2; h=Cc:To:In-Reply-To:References:Message-Id: Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date:From; bh=1LkTAo+m9WKRSreDzMStbwx7+niLQSYtLsSyhAAe21M=; b=XvAbdhO9KtxJO1qpncN+sUSEsM rU3XMLdFUByT85WjEVJWzsRO59VfiZ2o0E5izBBBLhW3Ll6QOncuu3kwkydfPHAiAB6zDEJeCzg27 Ubienf0YiWiBW5QjFDIcUEcyapQbnEFfYnd6qAtvGQKOnwuGLj6wwbVLKn7AC5oUxb0qQOWukETzt u5YM3L/DFC2UoNXwfcohWA5lGwVV6q+1xmA2iq0MB5rTeoDBwEyi4n3baWp/yXU3XlT/4cmaNtm6V bHF551DtBzyZaGnJJ1001WTg6DfkCnlY5hTcjPL3AUXB8hxSiV4JzUTNC9iiyr2S9QTASYWspjNOH GwlXgJFw==; Received: from [10.9.9.72] (helo=submission01.runbox) by mailtransmit02.runbox with esmtp (Exim 4.86_2) (envelope-from ) id 1uRs0B-0004by-0H; Wed, 18 Jun 2025 14:34:51 +0200 Received: by submission01.runbox with esmtpsa [Authenticated ID (604044)] (TLS1.2:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.93) id 1uRrzp-00DbRZ-RC; Wed, 18 Jun 2025 14:34:29 +0200 From: Michal Luczaj Date: Wed, 18 Jun 2025 14:34:02 +0200 Subject: [PATCH net 3/3] vsock: Fix transport_* TOCTOU 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: <20250618-vsock-transports-toctou-v1-3-dd2d2ede9052@rbox.co> References: <20250618-vsock-transports-toctou-v1-0-dd2d2ede9052@rbox.co> In-Reply-To: <20250618-vsock-transports-toctou-v1-0-dd2d2ede9052@rbox.co> To: Stefano Garzarella , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman Cc: virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Michal Luczaj X-Mailer: b4 0.14.2 Transport assignment may race with module unload. Protect new_transport from becoming a stale pointer. This also takes care of an insecure call in vsock_use_local_transport(); add a lockdep assert. BUG: unable to handle page fault for address: fffffbfff8056000 Oops: Oops: 0000 [#1] SMP KASAN RIP: 0010:vsock_assign_transport+0x366/0x600 Call Trace: vsock_connect+0x59c/0xc40 __sys_connect+0xe8/0x100 __x64_sys_connect+0x6e/0xc0 do_syscall_64+0x92/0x1c0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Signed-off-by: Michal Luczaj --- net/vmw_vsock/af_vsock.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index 337540efc237c8bc482a6730948fc773c00854f1..133d7c8d2231e5c2e5e6a697de3= b104fe05d8020 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -407,6 +407,8 @@ EXPORT_SYMBOL_GPL(vsock_enqueue_accept); =20 static bool vsock_use_local_transport(unsigned int remote_cid) { + lockdep_assert_held(&vsock_register_mutex); + if (!transport_local) return false; =20 @@ -464,6 +466,8 @@ int vsock_assign_transport(struct vsock_sock *vsk, stru= ct vsock_sock *psk) =20 remote_flags =3D vsk->remote_addr.svm_flags; =20 + mutex_lock(&vsock_register_mutex); + switch (sk->sk_type) { case SOCK_DGRAM: new_transport =3D transport_dgram; @@ -479,12 +483,15 @@ int vsock_assign_transport(struct vsock_sock *vsk, st= ruct vsock_sock *psk) new_transport =3D transport_h2g; break; default: - return -ESOCKTNOSUPPORT; + ret =3D -ESOCKTNOSUPPORT; + goto unlock; } =20 if (vsk->transport) { - if (vsk->transport =3D=3D new_transport) - return 0; + if (vsk->transport =3D=3D new_transport) { + ret =3D 0; + goto unlock; + } =20 /* transport->release() must be called with sock lock acquired. * This path can only be taken during vsock_connect(), where we @@ -508,8 +515,12 @@ int vsock_assign_transport(struct vsock_sock *vsk, str= uct vsock_sock *psk) /* We increase the module refcnt to prevent the transport unloading * while there are open sockets assigned to it. */ - if (!new_transport || !try_module_get(new_transport->module)) - return -ENODEV; + if (!new_transport || !try_module_get(new_transport->module)) { + ret =3D -ENODEV; + goto unlock; + } + + mutex_unlock(&vsock_register_mutex); =20 if (sk->sk_type =3D=3D SOCK_SEQPACKET) { if (!new_transport->seqpacket_allow || @@ -528,6 +539,9 @@ int vsock_assign_transport(struct vsock_sock *vsk, stru= ct vsock_sock *psk) vsk->transport =3D new_transport; =20 return 0; +unlock: + mutex_unlock(&vsock_register_mutex); + return ret; } EXPORT_SYMBOL_GPL(vsock_assign_transport); =20 --=20 2.49.0