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authorDan Carpenter <dan.carpenter@oracle.com>2020-01-15 20:49:04 +0300
committerJohan Hedberg <johan.hedberg@intel.com>2020-01-26 10:34:17 +0200
commit11eb85ec42dc8c7a7ec519b90ccf2eeae9409de8 (patch)
treea88ca07a4de1b08600afabe48fb8b92b15b5cc28 /net/bluetooth
parent18f81241b74fb49d576c83fbbab9a0b6e3bb20d4 (diff)
Bluetooth: Fix race condition in hci_release_sock()
Syzbot managed to trigger a use after free "KASAN: use-after-free Write in hci_sock_bind". I have reviewed the code manually and one possibly cause I have found is that we are not holding lock_sock(sk) when we do the hci_dev_put(hdev) in hci_sock_release(). My theory is that the bind and the release are racing against each other which results in this use after free. Reported-by: syzbot+eba992608adf3d796bcc@syzkaller.appspotmail.com Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Diffstat (limited to 'net/bluetooth')
-rw-r--r--net/bluetooth/hci_sock.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index 5756b124c2cb..9c4a093f8960 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -839,6 +839,8 @@ static int hci_sock_release(struct socket *sock)
if (!sk)
return 0;
+ lock_sock(sk);
+
switch (hci_pi(sk)->channel) {
case HCI_CHANNEL_MONITOR:
atomic_dec(&monitor_promisc);
@@ -886,6 +888,7 @@ static int hci_sock_release(struct socket *sock)
skb_queue_purge(&sk->sk_receive_queue);
skb_queue_purge(&sk->sk_write_queue);
+ release_sock(sk);
sock_put(sk);
return 0;
}