[PATCH 4.8 36/37] can: bcm: fix support for CAN FD frames

From: Greg Kroah-Hartman
Date: Wed Nov 30 2016 - 04:34:59 EST


4.8-stable review patch. If anyone has any objections, please let me know.

------------------

From: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>

commit 5499a6b22e5508b921c447757685b0a5e40a07ed upstream.

Since commit 6f3b911d5f29b98 ("can: bcm: add support for CAN FD frames") the
CAN broadcast manager supports CAN and CAN FD data frames.

As these data frames are embedded in struct can[fd]_frames which have a
different length the access to the provided array of CAN frames became
dependend of op->cfsiz. By using a struct canfd_frame pointer for the array of
CAN frames the new offset calculation based on op->cfsiz was accidently applied
to CAN FD frame element lengths.

This fix makes the pointer to the arrays of the different CAN frame types a
void pointer so that the offset calculation in bytes accesses the correct CAN
frame elements.

Reference: http://marc.info/?l=linux-netdev&m=147980658909653

Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Tested-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
net/can/bcm.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -77,7 +77,7 @@
(CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
(CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))

-#define CAN_BCM_VERSION "20160617"
+#define CAN_BCM_VERSION "20161123"

MODULE_DESCRIPTION("PF_CAN broadcast manager protocol");
MODULE_LICENSE("Dual BSD/GPL");
@@ -109,8 +109,9 @@ struct bcm_op {
u32 count;
u32 nframes;
u32 currframe;
- struct canfd_frame *frames;
- struct canfd_frame *last_frames;
+ /* void pointers to arrays of struct can[fd]_frame */
+ void *frames;
+ void *last_frames;
struct canfd_frame sframe;
struct canfd_frame last_sframe;
struct sock *sk;
@@ -681,7 +682,7 @@ static void bcm_rx_handler(struct sk_buf

if (op->flags & RX_FILTER_ID) {
/* the easiest case */
- bcm_rx_update_and_send(op, &op->last_frames[0], rxframe);
+ bcm_rx_update_and_send(op, op->last_frames, rxframe);
goto rx_starttimer;
}

@@ -1068,7 +1069,7 @@ static int bcm_rx_setup(struct bcm_msg_h

if (msg_head->nframes) {
/* update CAN frames content */
- err = memcpy_from_msg((u8 *)op->frames, msg,
+ err = memcpy_from_msg(op->frames, msg,
msg_head->nframes * op->cfsiz);
if (err < 0)
return err;
@@ -1118,7 +1119,7 @@ static int bcm_rx_setup(struct bcm_msg_h
}

if (msg_head->nframes) {
- err = memcpy_from_msg((u8 *)op->frames, msg,
+ err = memcpy_from_msg(op->frames, msg,
msg_head->nframes * op->cfsiz);
if (err < 0) {
if (op->frames != &op->sframe)
@@ -1163,6 +1164,7 @@ static int bcm_rx_setup(struct bcm_msg_h
/* check flags */

if (op->flags & RX_RTR_FRAME) {
+ struct canfd_frame *frame0 = op->frames;

/* no timers in RTR-mode */
hrtimer_cancel(&op->thrtimer);
@@ -1174,8 +1176,8 @@ static int bcm_rx_setup(struct bcm_msg_h
* prevent a full-load-loopback-test ... ;-]
*/
if ((op->flags & TX_CP_CAN_ID) ||
- (op->frames[0].can_id == op->can_id))
- op->frames[0].can_id = op->can_id & ~CAN_RTR_FLAG;
+ (frame0->can_id == op->can_id))
+ frame0->can_id = op->can_id & ~CAN_RTR_FLAG;

} else {
if (op->flags & SETTIMER) {