wifi: carl9170: fix buffer overflow in rx_stream failover path

[ Upstream commit a1a2199 ]

The failover continuation in carl9170_rx_stream() copies the full tlen
from the second USB transfer instead of capping at rx_failover_missing
bytes. When both transfers are near maximum size, the total exceeds the
65535-byte failover SKB, triggering skb_over_panic.

Limit the copy size to the missing byte count.

Fixes: a84fab3 ("carl9170: 802.11 rx/tx processing and usb backend")
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
Acked-by: Christian Lamparter <chunkeey@gmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=5c1ca6ccaa1215781cac
Link: https://patch.msgid.link/20260421134929.325662-4-tristmd@gmail.com
[Fix checkpatch CHECK:PARENTHESIS_ALIGNMENT]
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Tristan Madani

drivers/net/wireless/ath/carl9170/rx.c

@@ -918,7 +918,9 @@ static void carl9170_rx_stream(struct ar9170 *ar, void *buf, unsigned int len)
 				}
 			}
 
-			skb_put_data(ar->rx_failover, tbuf, tlen);
+			skb_put_data(ar->rx_failover, tbuf,
+				     min_t(unsigned int, tlen,
+					   ar->rx_failover_missing));
 			ar->rx_failover_missing -= tlen;
 
 			if (ar->rx_failover_missing <= 0) {