On Thu, Oct 14, 2021 at 05:26:40PM +0800, Zhang Changzhong wrote: > The receiver should abort TP if 'total message size' in TP.CM_RTS and > TP.CM_BAM is less than 9 or greater than 1785 [1], but currently the > j1939 stack only checks the upper bound and the receiver will accept the > following broadcast message: > vcan1 18ECFF00 [8] 20 08 00 02 FF 00 23 01 > vcan1 18EBFF00 [8] 01 00 00 00 00 00 00 00 > vcan1 18EBFF00 [8] 02 00 FF FF FF FF FF FF > > This patch adds check for the lower bound and abort illegal TP. > > [1] SAE-J1939-82 A.3.4 Row 2 and A.3.6 Row 6. > > Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") > Signed-off-by: Zhang Changzhong <zhangchangzhong@xxxxxxxxxx> Acked-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx> Thank you! > --- > net/can/j1939/j1939-priv.h | 1 + > net/can/j1939/transport.c | 2 ++ > 2 files changed, 3 insertions(+) > > diff --git a/net/can/j1939/j1939-priv.h b/net/can/j1939/j1939-priv.h > index f6df208..16af1a7 100644 > --- a/net/can/j1939/j1939-priv.h > +++ b/net/can/j1939/j1939-priv.h > @@ -330,6 +330,7 @@ int j1939_session_activate(struct j1939_session *session); > void j1939_tp_schedule_txtimer(struct j1939_session *session, int msec); > void j1939_session_timers_cancel(struct j1939_session *session); > > +#define J1939_MIN_TP_PACKET_SIZE 9 > #define J1939_MAX_TP_PACKET_SIZE (7 * 0xff) > #define J1939_MAX_ETP_PACKET_SIZE (7 * 0x00ffffff) > > diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c > index bb5c4b8..b685d31 100644 > --- a/net/can/j1939/transport.c > +++ b/net/can/j1939/transport.c > @@ -1609,6 +1609,8 @@ j1939_session *j1939_xtp_rx_rts_session_new(struct j1939_priv *priv, > abort = J1939_XTP_ABORT_FAULT; > else if (len > priv->tp_max_packet_size) > abort = J1939_XTP_ABORT_RESOURCE; > + else if (len < J1939_MIN_TP_PACKET_SIZE) > + abort = J1939_XTP_ABORT_FAULT; > } > > if (abort != J1939_XTP_NO_ABORT) { > -- > 2.9.5 > > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |