[PATCH] fix: net/bluetooth: iso_conn_del: extra iso_conn_put on iso_sock_hold failure path

[WenTao Liang <vulab@iscas.ac.cn>]

In iso_conn_del(), iso_conn_hold_unless_zero() acquires a temporary
  reference which is correctly balanced by iso_conn_put() at line 279. When
  iso_sock_hold() returns NULL (sk == NULL), an additional
  iso_conn_put(conn) is called, dropping hcon's reference to conn too
  early. The caller (e.g., hci_conn_del) will later also iso_conn_put(),
  causing a double-free or use-after-free.

Remove the extra iso_conn_put(conn) on the sk == NULL path.

Cc: stable@vger.kernel.org
Fixes: dc26097bdb86 ("Bluetooth: ISO: Use kref to track lifetime of iso_conn")
Signed-off-by: WenTao Liang <vulab@iscas.ac.cn>
---
 net/bluetooth/iso.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c
index 3abd8111dda8..99755671e469 100644
--- a/net/bluetooth/iso.c
+++ b/net/bluetooth/iso.c
@@ -278,10 +278,8 @@ static void iso_conn_del(struct hci_conn *hcon, int err)
 	iso_conn_unlock(conn);
 	iso_conn_put(conn);
 
-	if (!sk) {
-		iso_conn_put(conn);
+	if (!sk)
 		return;
-	}
 
 	lock_sock(sk);
 	iso_sock_clear_timer(sk);
-- 
2.39.5 (Apple Git-154)