From f4712fa993f688d0a48e0c28728fcdeb88c1ea58 Mon Sep 17 00:00:00 2001 From: Desmond Cheong Zhi Xi Date: Thu, 2 Sep 2021 23:13:05 -0400 Subject: Bluetooth: call sock_hold earlier in sco_conn_del In sco_conn_del, conn->sk is read while holding on to the sco_conn.lock to avoid races with a socket that could be released concurrently. However, in between unlocking sco_conn.lock and calling sock_hold, it's possible for the socket to be freed, which would cause a use-after-free write when sock_hold is finally called. To fix this, the reference count of the socket should be increased while the sco_conn.lock is still held. Signed-off-by: Desmond Cheong Zhi Xi Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/sco.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/bluetooth/sco.c') diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c index b62c91c627e2..4a057f99b60a 100644 --- a/net/bluetooth/sco.c +++ b/net/bluetooth/sco.c @@ -187,10 +187,11 @@ static void sco_conn_del(struct hci_conn *hcon, int err) /* Kill socket */ sco_conn_lock(conn); sk = conn->sk; + if (sk) + sock_hold(sk); sco_conn_unlock(conn); if (sk) { - sock_hold(sk); lock_sock(sk); sco_sock_clear_timer(sk); sco_chan_del(sk, err); -- cgit v1.2.3