[PATCH] can: peak_usb: fix slab info leak

From: Johan Hovold
Date: Wed Oct 23 2019 - 04:27:31 EST

Fix a small slab info leak due to a failure to clear the command buffer
at allocation.

The first 16 bytes of the command buffer are always sent to the device
in pcan_usb_send_cmd() even though only the first two may have been
initialised in case no argument payload is provided (e.g. when waiting
for a response).

Fixes: bb4785551f64 ("can: usb: PEAK-System Technik USB adapters driver core")
Cc: stable <stable@xxxxxxxxxxxxxxx> # 3.4
Reported-by: syzbot+863724e7128e14b26732@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
drivers/net/can/usb/peak_usb/pcan_usb_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_core.c b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
index 65dce642b86b..0b7766b715fd 100644
--- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
@@ -750,7 +750,7 @@ static int peak_usb_create_dev(const struct peak_usb_adapter *peak_usb_adapter,
dev = netdev_priv(netdev);

/* allocate a buffer large enough to send commands */
- dev->cmd_buf = kmalloc(PCAN_USB_MAX_CMD_LEN, GFP_KERNEL);
+ dev->cmd_buf = kzalloc(PCAN_USB_MAX_CMD_LEN, GFP_KERNEL);
if (!dev->cmd_buf) {
err = -ENOMEM;
goto lbl_free_candev;