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>
---
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
