[PATCH 5.18 107/158] amt: drop unexpected multicast data

[Greg Kroah-Hartman]

From: Taehee Yoo <ap420073@xxxxxxxxx>

[ Upstream commit e882827d5b8942a27b4d28548aa27562a3a7e94c ]

AMT gateway interface should not receive unexpected multicast data.
Multicast data message type should be received after sending an update
message, which means all establishment between gateway and relay is
finished.
So, amt_multicast_data_handler() checks amt->status.

Fixes: cbc21dc1cfe9 ("amt: add data plane of amt interface")
Signed-off-by: Taehee Yoo <ap420073@xxxxxxxxx>
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/amt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/amt.c b/drivers/net/amt.c
index 5c65908abd5a..4277924ab3b9 100644
--- a/drivers/net/amt.c
+++ b/drivers/net/amt.c
@@ -2282,6 +2282,9 @@ static bool amt_multicast_data_handler(struct amt_dev *amt, struct sk_buff *skb)
 	struct ethhdr *eth;
 	struct iphdr *iph;
 
+	if (READ_ONCE(amt->status) != AMT_STATUS_SENT_UPDATE)
+		return true;
+
 	hdr_size = sizeof(*amtmd) + sizeof(struct udphdr);
 	if (!pskb_may_pull(skb, hdr_size))
 		return true;
-- 
2.35.1