[PATCH net 2/3] can: j1939: j1939_can_recv(): ignore messages with invalid source address

[Zhang Changzhong]

According to SAE-J1939-82 2015 (A.3.6 Row 2), a receiver should never
send TP.CM_CTS to the global address, so we can add a check in
j1939_can_recv() to drop messages with invalid source address.

Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Signed-off-by: Zhang Changzhong <zhangchangzhong@xxxxxxxxxx>
---
 net/can/j1939/main.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
index 08c8606..4f1e4bb 100644
--- a/net/can/j1939/main.c
+++ b/net/can/j1939/main.c
@@ -75,6 +75,10 @@ static void j1939_can_recv(struct sk_buff *iskb, void *data)
 	skcb->addr.pgn = (cf->can_id >> 8) & J1939_PGN_MAX;
 	/* set default message type */
 	skcb->addr.type = J1939_TP;
+	if (!j1939_address_is_valid(skcb->addr.sa))
+		/* ignore messages whose sa is broadcast address */
+		goto done;
+
 	if (j1939_pgn_is_pdu1(skcb->addr.pgn)) {
 		/* Type 1: with destination address */
 		skcb->addr.da = skcb->addr.pgn;
-- 
2.9.5