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authorOliver Hartkopp <oliver@hartkopp.net>2009-12-12 04:13:21 +0000
committerDavid S. Miller <davem@davemloft.net>2009-12-13 19:47:42 -0800
commitc7cd606f60e7679c7f9eee7010f02a6f000209c1 (patch)
tree31c19fd7617ede807757b0ae5c29d218587dc43f /drivers/net/can/usb
parentd90a909e1f3e006a1d57fe11fd417173b6494701 (diff)
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 <oliver@hartkopp.net> Signed-off-by: Wolfgang Grandegger <wg@grandegger.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/can/usb')
-rw-r--r--drivers/net/can/usb/ems_usb.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c
index 591eb0eb1c2..efbb05c71bf 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)