[PATCH v1 5/5] can: j1939: transport: j1939_xtp_rx_dat_one(): compare own packets to detect corruptions
From: Oleksij Rempel <o.rempel@pengutronix.de>
Date: 2020-08-07 11:00:10
Also in:
linux-can
Subsystem:
can network layer, can-j1939 network layer, the rest · Maintainers:
Oliver Hartkopp, Marc Kleine-Budde, Robin van der Gracht, Oleksij Rempel, Linus Torvalds
Since the stack relays on receiving own packets, it was overwriting own transmit buffer from received packets. At least theoretically, the received echo buffer can be corrupt or changed and the session partner can request to resend previous data. In this case we will re-send bad data. With this patch we will stop to overwrite own TX buffer and use it for sanity checking. Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> --- net/can/j1939/transport.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
index 90a2baac8a4a..5cf107cb447c 100644
--- a/net/can/j1939/transport.c
+++ b/net/can/j1939/transport.c@@ -1792,7 +1792,20 @@ static void j1939_xtp_rx_dat_one(struct j1939_session *session, } tpdat = se_skb->data; - memcpy(&tpdat[offset], &dat[1], nbytes); + if (!session->transmission) { + memcpy(&tpdat[offset], &dat[1], nbytes); + } else { + int err; + + err = memcmp(&tpdat[offset], &dat[1], nbytes); + if (err) + netdev_err_once(priv->ndev, + "%s: 0x%p: Data of RX-looped back packet (%*ph) doesn't match TX data (%*ph)!\n", + __func__, session, + nbytes, &dat[1], + nbytes, &tpdat[offset]); + } + if (packet == session->pkt.rx) session->pkt.rx++;
--
2.28.0