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:     Mauricio Faria de Oliveira <mfo@canonical.com>,
        Jens Axboe <axboe@kernel.dk>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL 4.14 69/89] partitions/aix: fix usage of uninitialized
 lv_info and lvname structures
Thread-Topic: [PATCH AUTOSEL 4.14 69/89] partitions/aix: fix usage of
 uninitialized lv_info and lvname structures
Thread-Index: AQHUQr3pZpBRrMcSzEyAmJnfiPOoCg==
Date:   Sun, 2 Sep 2018 13:07:34 +0000
Message-ID: <20180902064918.183387-69-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: 56c61159-878e-4574-fc1a-08d610d5170b
X-MS-Exchange-CrossTenant-originalarrivaltime: 02 Sep 2018 13:07:34.0524
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY4PR21MB0149
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: Mauricio Faria de Oliveira <mfo@canonical.com>

[ Upstream commit 14cb2c8a6c5dae57ee3e2da10fa3db2b9087e39e ]

The if-block that sets a successful return value in aix_partition()
uses 'lvip[].pps_per_lv' and 'n[].name' potentially uninitialized.

For example, if 'numlvs' is zero or alloc_lvn() fails, neither is
initialized, but are used anyway if alloc_pvd() succeeds after it.

So, make the alloc_pvd() call conditional on their initialization.

This has been hit when attaching an apparently corrupted/stressed
AIX LUN, misleading the kernel to pr_warn() invalid data and hang.

    [...] partition (null) (11 pp's found) is not contiguous
    [...] partition (null) (2 pp's found) is not contiguous
    [...] partition (null) (3 pp's found) is not contiguous
    [...] partition (null) (64 pp's found) is not contiguous

Fixes: 6ceea22bbbc8 ("partitions: add aix lvm partition support files")
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 block/partitions/aix.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/partitions/aix.c b/block/partitions/aix.c
index 238aca56f552..903f3ed175d0 100644
--- a/block/partitions/aix.c
+++ b/block/partitions/aix.c
@@ -178,7 +178,7 @@ int aix_partition(struct parsed_partitions *state)
 	u32 vgda_sector =3D 0;
 	u32 vgda_len =3D 0;
 	int numlvs =3D 0;
-	struct pvd *pvd;
+	struct pvd *pvd =3D NULL;
 	struct lv_info {
 		unsigned short pps_per_lv;
 		unsigned short pps_found;
@@ -232,10 +232,11 @@ int aix_partition(struct parsed_partitions *state)
 				if (lvip[i].pps_per_lv)
 					foundlvs +=3D 1;
 			}
+			/* pvd loops depend on n[].name and lvip[].pps_per_lv */
+			pvd =3D alloc_pvd(state, vgda_sector + 17);
 		}
 		put_dev_sector(sect);
 	}
-	pvd =3D alloc_pvd(state, vgda_sector + 17);
 	if (pvd) {
 		int numpps =3D be16_to_cpu(pvd->pp_count);
 		int psn_part1 =3D be32_to_cpu(pvd->psn_part1);
--=20
2.17.1