From: Zhang Changzhong zhangchangzhong@huawei.com

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") Link: https://lore.kernel.org/all/1634203601-3460-1-git-send-email-zhangchangzhong... Cc: stable@vger.kernel.org Signed-off-by: Zhang Changzhong zhangchangzhong@huawei.com Acked-by: Oleksij Rempel o.rempel@pengutronix.de Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de --- 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 f6df20808f5e..16af1a7f80f6 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 1ea6fee3d986..6c0a0ebdd024 100644 --- a/net/can/j1939/transport.c +++ b/net/can/j1939/transport.c @@ -1608,6 +1608,8 @@ 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) {