From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755274AbdKODAp (ORCPT ); Tue, 14 Nov 2017 22:00:45 -0500 Received: from omzsmtpe02.verizonbusiness.com ([199.249.25.209]:39893 "EHLO omzsmtpe02.verizonbusiness.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756688AbdKOCs5 (ORCPT ); Tue, 14 Nov 2017 21:48:57 -0500 From: alexander.levin@verizon.com Cc: Juergen Gross , alexander.levin@verizon.com X-Host: surveyor.tdc.vzwcorp.com To: "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: [PATCH AUTOSEL for 4.4 28/28] xen: xenbus driver must not accept invalid transaction ids Thread-Topic: [PATCH AUTOSEL for 4.4 28/28] xen: xenbus driver must not accept invalid transaction ids Thread-Index: AQHTXbvh87F5PXGqbEioOgd+oV4+SA== Date: Wed, 15 Nov 2017 02:46:05 +0000 Message-ID: <20171115024551.5988-28-alexander.levin@verizon.com> References: <20171115024551.5988-1-alexander.levin@verizon.com> In-Reply-To: <20171115024551.5988-1-alexander.levin@verizon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-messagesentrepresentingtype: 1 x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.144.60.250] Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by nfs id vAF30pe4030931 From: Juergen Gross [ Upstream commit 639b08810d6ad74ded2c5f6e233c4fcb9d147168 ] When accessing Xenstore in a transaction the user is specifying a transaction id which he normally obtained from Xenstore when starting the transaction. Xenstore is validating a transaction id against all known transaction ids of the connection the request came in. As all requests of a domain not being the one where Xenstore lives share one connection, validation of transaction ids of different users of Xenstore in that domain should be done by the kernel of that domain being the multiplexer between the Xenstore users in that domain and Xenstore. In order to prohibit one Xenstore user "hijacking" a transaction from another user the xenbus driver has to verify a given transaction id against all known transaction ids of the user before forwarding it to Xenstore. Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross Signed-off-by: Sasha Levin --- drivers/xen/xenbus/xenbus_dev_frontend.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c index 0e0eb10f82a0..816a0e08ef10 100644 --- a/drivers/xen/xenbus/xenbus_dev_frontend.c +++ b/drivers/xen/xenbus/xenbus_dev_frontend.c @@ -316,7 +316,7 @@ static int xenbus_write_transaction(unsigned msg_type, rc = -ENOMEM; goto out; } - } else if (msg_type == XS_TRANSACTION_END) { + } else if (u->u.msg.tx_id != 0) { list_for_each_entry(trans, &u->transactions, list) if (trans->handle.id == u->u.msg.tx_id) break; -- 2.11.0