[PATCH] platform/x86: panasonic-laptop: set pcc after null device check to avoid null pointer dereference

[PATCH] platform/x86: panasonic-laptop: set pcc after null device check to avoid null pointer dereference

[Colin King]

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

acpi_pcc_hotkey_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 pcc, then check if pcc is null.

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

diff --git a/drivers/platform/x86/panasonic-laptop.c b/drivers/platform/x86/panasonic-laptop.c
index 3f87097..39c1ebc 100644
--- a/drivers/platform/x86/panasonic-laptop.c
+++ b/drivers/platform/x86/panasonic-laptop.c
@@ -651,9 +651,13 @@ out_hotkey:
 
 static int acpi_pcc_hotkey_remove(struct acpi_device *device)
 {
-	struct pcc_acpi *pcc = acpi_driver_data(device);
+	struct pcc_acpi *pcc;
+
+	if (!device)
+		return -EINVAL;
 
-	if (!device || !pcc)
+	pcc = acpi_driver_data(device);
+	if (!pcc)
 		return -EINVAL;
 
 	sysfs_remove_group(&device->dev.kobj, &pcc_attr_group);
-- 
2.7.4

Re: [PATCH] platform/x86: panasonic-laptop: set pcc after null device check to avoid null pointer dereference

[Harald Welte]

On Mon, Mar 28, 2016 at 05:26:12PM +0100, Colin King wrote:
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Acked-by: Harald Welte <laforge@gnumonks.org>
-- 
- Harald Welte <laforge@gnumonks.org>           http://laforge.gnumonks.org/
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