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From:   Zhang Changzhong <zhangchangzhong@huawei.com>
To:     Robin van der Gracht <robin@protonic.nl>,
        Oleksij Rempel <linux@rempel-privat.de>,
        <kernel@pengutronix.de>, Oliver Hartkopp <socketcan@hartkopp.net>,
        Marc Kleine-Budde <mkl@pengutronix.de>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>
CC:     Zhang Changzhong <zhangchangzhong@huawei.com>,
        <linux-can@vger.kernel.org>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH net 2/3] can: j1939: j1939_can_recv(): ignore messages with invalid source address
Date:   Thu, 21 Oct 2021 22:04:16 +0800
Message-ID: <1634825057-47915-3-git-send-email-zhangchangzhong@huawei.com>
In-Reply-To: <1634825057-47915-1-git-send-email-zhangchangzhong@huawei.com>
References: <1634825057-47915-1-git-send-email-zhangchangzhong@huawei.com>
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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@huawei.com>
---
 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