diff mbox series

[5.8,134/255] can: j1939: transport: j1939_xtp_rx_dat_one(): compare own packets to detect corruptions

Message ID 20200901151007.136796033@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH Sept. 1, 2020, 3:09 p.m. UTC 
From: Oleksij Rempel <o.rempel@pengutronix.de>

[ Upstream commit e052d0540298bfe0f6cbbecdc7e2ea9b859575b2 ]

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>
Link: https://lore.kernel.org/r/20200807105200.26441-6-o.rempel@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/can/j1939/transport.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
index dbd215cbc53d8..a8dd956b5e8e1 100644
--- a/net/can/j1939/transport.c
+++ b/net/can/j1939/transport.c
@@ -1803,7 +1803,20 @@  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++;