[PATCH 5.4 131/214] can: j1939: transport: j1939_xtp_rx_dat_one(): compare own packets to detect corruptions

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>

[ 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@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200807105200.26441-6-o.rempel@xxxxxxxxxxxxxx
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 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++;
 
-- 
2.25.1






[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux