Bluetooth: LE L2CAP: Disconnect if sum of payload sizes exceed SDU

[ Upstream commit b6a2bf4 ]

Core 6.0, Vol 3, Part A, 3.4.3:
"... If the sum of the payload sizes for the K-frames exceeds the
specified SDU length, the receiver shall disconnect the channel."

This fixes L2CAP/LE/CFC/BV-27-C (running together with 'l2test -r -P
0x0027 -V le_public').

Fixes: aac23bf ("Bluetooth: Implement LE L2CAP reassembly")
Signed-off-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: ceggers-arri

net/bluetooth/l2cap_core.c

@@ -6721,6 +6721,7 @@ static int l2cap_ecred_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)
 
 	if (chan->sdu->len + skb->len > chan->sdu_len) {
 		BT_ERR("Too much LE L2CAP data received");
+		l2cap_send_disconn_req(chan, ECONNRESET);
 		err = -EINVAL;
 		goto failed;
 	}