Commit e052d054 authored by Oleksij Rempel's avatar Oleksij Rempel Committed by Marc Kleine-Budde

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: default avatarOleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20200807105200.26441-6-o.rempel@pengutronix.deSigned-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 840835c9
...@@ -1792,7 +1792,20 @@ static void j1939_xtp_rx_dat_one(struct j1939_session *session, ...@@ -1792,7 +1792,20 @@ static void j1939_xtp_rx_dat_one(struct j1939_session *session,
} }
tpdat = se_skb->data; 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) if (packet == session->pkt.rx)
session->pkt.rx++; session->pkt.rx++;
......
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