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:     Anton Vasilyev <vasilyev@ispras.ru>,
        Linus Walleij <linus.walleij@linaro.org>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL 4.14 51/89] gpio: ml-ioh: Fix buffer underwrite on
 probe error path
Thread-Topic: [PATCH AUTOSEL 4.14 51/89] gpio: ml-ioh: Fix buffer underwrite
 on probe error path
Thread-Index: AQHUQr3dQ3MApJnmQkuxF2uSKO1jCg==
Date:   Sun, 2 Sep 2018 13:07:13 +0000
Message-ID: <20180902064918.183387-51-alexander.levin@microsoft.com>
References: <20180902064918.183387-1-alexander.levin@microsoft.com>
In-Reply-To: <20180902064918.183387-1-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: f791c73e-e5ad-4194-d1bc-08d610d512f4
X-MS-Exchange-CrossTenant-originalarrivaltime: 02 Sep 2018 13:07:13.2961
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR21MB0503
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: Anton Vasilyev <vasilyev@ispras.ru>

[ Upstream commit 4bf4eed44bfe288f459496eaf38089502ef91a79 ]

If ioh_gpio_probe() fails on devm_irq_alloc_descs() then chip may point
to any element of chip_save array, so reverse iteration from pointer chip
may become chip_save[-1] and gpiochip_remove() will operate with wrong
memory.

The patch fix the error path of ioh_gpio_probe() to correctly bypass
chip_save array.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/gpio/gpio-ml-ioh.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-ml-ioh.c b/drivers/gpio/gpio-ml-ioh.c
index 4b80e996d976..1022fe8d09c7 100644
--- a/drivers/gpio/gpio-ml-ioh.c
+++ b/drivers/gpio/gpio-ml-ioh.c
@@ -497,9 +497,10 @@ static int ioh_gpio_probe(struct pci_dev *pdev,
 	return 0;
=20
 err_gpiochip_add:
+	chip =3D chip_save;
 	while (--i >=3D 0) {
-		chip--;
 		gpiochip_remove(&chip->gpio);
+		chip++;
 	}
 	kfree(chip_save);
=20
--=20
2.17.1