linux-kernel - [PATCH] intel_menlow: set cdev after null device check to avoid null pointer dereference

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1459181919-13825-1-git-send-email-colin.king@canonical.com>
Date:	Mon, 28 Mar 2016 17:18:39 +0100
From:	Colin King <colin.king@...onical.com>
To:	Sujith Thomas <sujith.thomas@...el.com>,
	Darren Hart <dvhart@...radead.org>,
	platform-driver-x86@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH] intel_menlow: set cdev after null device check to avoid null pointer dereference

From: Colin Ian King <colin.king@...onical.com>

intel_menlow_memory_remove sanity checks to see if device is null, however,
this check is performed after we have already passed device into a call
to acpi_driver_data.  If device is null, then acpi_driver_data will produce
a null pointer dereference on device. The correct action is to sanity check
device, then assign cdev, then check if cdev is null.

Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/platform/x86/intel_menlow.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/intel_menlow.c b/drivers/platform/x86/intel_menlow.c
index 0a919d8..185a1bd 100644
--- a/drivers/platform/x86/intel_menlow.c
+++ b/drivers/platform/x86/intel_menlow.c
@@ -196,9 +196,13 @@ static int intel_menlow_memory_add(struct acpi_device *device)
 
 static int intel_menlow_memory_remove(struct acpi_device *device)
 {
-	struct thermal_cooling_device *cdev = acpi_driver_data(device);
+	struct thermal_cooling_device *cdev;
+
+	if (!device)
+		return -EINVAL;
 
-	if (!device || !cdev)
+	cdev = acpi_driver_data(device);
+	if (!cdev)
 		return -EINVAL;
 
 	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
-- 
2.7.4