From: Zhang Changzhong zhangchangzhong@huawei.com

commit 164051a6ab5445bd97f719f50b16db8b32174269 upstream.

The TP.CM_BAM message must be sent to the global address [1], so add a check to drop TP.CM_BAM sent to a non-global address.

Without this patch, the receiver will treat the following packets as normal RTS/CTS transport: 18EC0102#20090002FF002301 18EB0102#0100000000000000 18EB0102#020000FFFFFFFFFF

[1] SAE-J1939-82 2015 A.3.3 Row 1.

Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Link: https://lore.kernel.org/all/1635431907-15617-4-git-send-email-zhangchangzhon... 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 --- changes: - rebase against v5.10.82

net/can/j1939/transport.c | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/net/can/j1939/transport.c b/net/can/j1939/transport.c index fe35fdad35c9..9c39b0f5d6e0 100644 --- a/net/can/j1939/transport.c +++ b/net/can/j1939/transport.c @@ -2004,6 +2004,12 @@ static void j1939_tp_cmd_recv(struct j1939_priv *priv, struct sk_buff *skb) extd = J1939_ETP; fallthrough; case J1939_TP_CMD_BAM: + if (cmd == J1939_TP_CMD_BAM && !j1939_cb_is_broadcast(skcb)) { + netdev_err_once(priv->ndev, "%s: BAM to unicast (%02x), ignoring!\n", + __func__, skcb->addr.sa); + return; + } + fallthrough; case J1939_TP_CMD_RTS: /* fall through */ if (skcb->addr.type != extd) return;