[PATCH 5.7 071/124] can: j1939: transport: j1939_simple_recv(): ignore local J1939 messages send not by J1939 stack

Greg Kroah-Hartman
2020-08-24T08:43:27Z

From: Oleksij Rempel <o.rempel@pengutronix.de>

[ Upstream commit b43e3a82bc432c1caaed8950e7662c143470c54c ]

In current J1939 stack implementation, we process all locally send
messages as own messages. Even if it was send by CAN_RAW socket.

To reproduce it use following commands:
testj1939 -P -r can0:0x80 &
cansend can0 18238040#0123

This step will trigger false positive not critical warning:
j1939_simple_recv: Received already invalidated message

With this patch we add additional check to make sure, related skb is own
echo message.

Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20200807105200.26441-2-o.rempel@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/can/j1939/socket.c | 1 +
net/can/j1939/transport.c | 4 ++++
2 files changed, 5 insertions(+)

diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c
index 1b7dc1a8547f3..bf9fd6ee88fe0 100644
--- a/net/can/j1939/socket.c
+++ b/net/can/j1939/socket.c
@@ -398,6 +398,7 @@ static int j1939_sk_init(struct sock *sk)
spin_lock_init(&jsk->sk_session_queue_lock);
INIT_LIST_HEAD(&jsk->sk_session_queue);
sk->sk_destruct = j1939_sk_sock_destruct;
+ sk->sk_protocol = CAN_J1939;

return 0;
}
diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c
index 5bfe6bf15a999..30957c9a8eb7a 100644
--- a/net/can/j1939/transport.c
+++ b/net/can/j1939/transport.c
@@ -2032,6 +2032,10 @@ void j1939_simple_recv(struct j1939_priv *priv, struct sk_buff *skb)
if (!skb->sk)
return;

+ if (skb->sk->sk_family != AF_CAN ||
+ skb->sk->sk_protocol != CAN_J1939)
+ return;
+
j1939_session_list_lock(priv);
session = j1939_session_get_simple(priv, skb);
j1939_session_list_unlock(priv);
--
2.25.1