Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Dan Carpenter <dan.carpenter@oracle.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL 4.18 005/136] vmci: type promotion bug in
 qp_host_get_user_memory()
Thread-Topic: [PATCH AUTOSEL 4.18 005/136] vmci: type promotion bug in
 qp_host_get_user_memory()
Thread-Index: AQHUTjKO4PYqOSy6V0GMYHxZIZGsMw==
Date:   Mon, 17 Sep 2018 03:00:13 +0000
Message-ID: <20180917030006.245495-5-alexander.levin@microsoft.com>
References: <20180917030006.245495-1-alexander.levin@microsoft.com>
In-Reply-To: <20180917030006.245495-1-alexander.levin@microsoft.com>
Accept-Language: en-US
Content-Language: en-US
received-spf: None (protection.outlook.com: microsoft.com does not designate
 permitted sender hosts)
spamdiagnosticoutput: 1:99
spamdiagnosticmetadata: NSPM
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-MS-Exchange-CrossTenant-Network-Message-Id: 3bdd61e9-ab5b-44cb-5d12-08d61c49b0a8
X-MS-Exchange-CrossTenant-originalarrivaltime: 17 Sep 2018 03:00:14.0424
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR21MB0134
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit 7fb2fd4e25fc1fb10dcb30b5519de257cfeae84c ]

The problem is that if get_user_pages_fast() fails and returns a
negative error code, it gets type promoted to a high positive value and
treated as a success.

Fixes: 06164d2b72aa ("VMCI: queue pairs implementation.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/misc/vmw_vmci/vmci_queue_pair.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmc=
i/vmci_queue_pair.c
index b4d7774cfe07..d95e8648e7b3 100644
--- a/drivers/misc/vmw_vmci/vmci_queue_pair.c
+++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c
@@ -668,7 +668,7 @@ static int qp_host_get_user_memory(u64 produce_uva,
 	retval =3D get_user_pages_fast((uintptr_t) produce_uva,
 				     produce_q->kernel_if->num_pages, 1,
 				     produce_q->kernel_if->u.h.header_page);
-	if (retval < produce_q->kernel_if->num_pages) {
+	if (retval < (int)produce_q->kernel_if->num_pages) {
 		pr_debug("get_user_pages_fast(produce) failed (retval=3D%d)",
 			retval);
 		qp_release_pages(produce_q->kernel_if->u.h.header_page,
@@ -680,7 +680,7 @@ static int qp_host_get_user_memory(u64 produce_uva,
 	retval =3D get_user_pages_fast((uintptr_t) consume_uva,
 				     consume_q->kernel_if->num_pages, 1,
 				     consume_q->kernel_if->u.h.header_page);
-	if (retval < consume_q->kernel_if->num_pages) {
+	if (retval < (int)consume_q->kernel_if->num_pages) {
 		pr_debug("get_user_pages_fast(consume) failed (retval=3D%d)",
 			retval);
 		qp_release_pages(consume_q->kernel_if->u.h.header_page,
--=20
2.17.1