can: isotp: isotp_bind(): return -EINVAL on incorrect CAN ID formatting

Commit 3ea566422cbd ("can: isotp: sanitize CAN ID checks in
isotp_bind()") checks the given CAN ID address information by
sanitizing the input values.

This check (silently) removes obsolete bits by masking the given CAN
IDs.

Derek Will suggested to give a feedback to the application programmer
when the 'sanitizing' was actually needed which means the programmer
provided CAN ID content in a wrong format (e.g. SFF CAN IDs with a CAN
ID > 0x7FF).

Link: https://lore.kernel.org/all/20220515181633.76671-1-socketcan@hartkopp.net
Suggested-by: Derek Will <derekrobertwill@gmail.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/net/can/isotp.c b/net/can/isotp.c
index 2caeeae..4a4007f 100644 (file)
--- a/net/can/isotp.c
+++ b/net/can/isotp.c
@@ -1232,6 +1232,11 @@ static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
        else
                rx_id &= CAN_SFF_MASK;
 
+       /* give feedback on wrong CAN-ID values */
+       if (tx_id != addr->can_addr.tp.tx_id ||
+           rx_id != addr->can_addr.tp.rx_id)
+               return -EINVAL;
+
        if (!addr->can_ifindex)
                return -ENODEV;