From: Oleksij Rempel Date: Fri, 7 Aug 2020 10:52:00 +0000 (+0200) Subject: can: j1939: transport: j1939_xtp_rx_dat_one(): compare own packets to detect corruptions X-Git-Tag: v5.10.7~1808^2~35^2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e052d0540298bfe0f6cbbecdc7e2ea9b859575b2;p=platform%2Fkernel%2Flinux-rpi.git can: j1939: transport: j1939_xtp_rx_dat_one(): compare own packets to detect corruptions 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 Link: https://lore.kernel.org/r/20200807105200.26441-6-o.rempel@pengutronix.de Signed-off-by: Marc Kleine-Budde --- diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c index 90a2baa..5cf107c 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++;