From c7cd606f60e7679c7f9eee7010f02a6f000209c1 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Sat, 12 Dec 2009 04:13:21 +0000 Subject: can: Fix data length code handling in rx path A valid CAN dataframe can have a data length code (DLC) of 0 .. 8 data bytes. When reading the CAN controllers register the 4-bit value may contain values from 0 .. 15 which may exceed the reserved space in the socket buffer! The ISO 11898-1 Chapter 8.4.2.3 (DLC field) says that register values > 8 should be reduced to 8 without any error reporting or frame drop. This patch introduces a new helper macro to cast a given 4-bit data length code (dlc) to __u8 and ensure the DLC value to be max. 8 bytes. The different handlings in the rx path of the CAN netdevice drivers are fixed. Signed-off-by: Oliver Hartkopp Signed-off-by: Wolfgang Grandegger Signed-off-by: David S. Miller --- drivers/net/can/usb/ems_usb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/net/can/usb/ems_usb.c') diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c index 591eb0eb1c2b..efbb05c71bf4 100644 --- a/drivers/net/can/usb/ems_usb.c +++ b/drivers/net/can/usb/ems_usb.c @@ -316,7 +316,7 @@ static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg) return; cf->can_id = le32_to_cpu(msg->msg.can_msg.id); - cf->can_dlc = min_t(u8, msg->msg.can_msg.length, 8); + cf->can_dlc = get_can_dlc(msg->msg.can_msg.length & 0xF); if (msg->type == CPC_MSG_TYPE_EXT_CAN_FRAME || msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME) -- cgit v1.2.3