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

From: Colin King
Date: Mon Mar 28 2016 - 12:26:21 EST

From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
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);