[PATCH v4 10/10] can: peak_usb: only dump received bytes on decode error

[Stéphane Grosjean]

From: Stéphane Grosjean <s.grosjean@xxxxxxxxxxxxxx>

When the decoding of a received URB fails, peak_usb_read_bulk_callback()
dumps the whole RX buffer to the kernel log. The buffer is allocated with
kmalloc() and its size is the adapter RX buffer size (up to 2048 bytes),
so the bytes beyond urb->actual_length are uninitialized memory or
leftovers from previous transfers.

Dump only the urb->actual_length bytes received from the device. Since a
faulty or malicious device can make every transfer fail to decode, also
rate limit the dump.

Fixes: bb4785551f64 ("can: usb: PEAK-System Technik USB adapters driver core")
Signed-off-by: Stéphane Grosjean <s.grosjean@xxxxxxxxxxxxxx>
---
 drivers/net/can/usb/peak_usb/pcan_usb_core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

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 ccfc26d3e5a6..b86ea6f6b07c 100644
--- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
@@ -265,10 +265,10 @@ static void peak_usb_read_bulk_callback(struct urb *urb)
 		/* handle these kinds of msgs only if _start callback called */
 		if (test_bit(PCAN_USB_STATE_STARTED, &dev->state)) {
 			err = dev->adapter->dev_decode_buf(dev, urb);
-			if (err)
+			if (err && net_ratelimit())
 				pcan_dump_mem("received usb message",
 					      urb->transfer_buffer,
-					      urb->transfer_buffer_length);
+					      urb->actual_length);
 		}
 	}
 

-- 
2.53.0