Bluetooth: Fix race condition in hci_release_sock()
authorDan Carpenter <dan.carpenter@oracle.com>
Wed, 15 Jan 2020 17:49:04 +0000 (20:49 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 5 Feb 2020 13:05:47 +0000 (13:05 +0000)
commit94fd874c64d71fbc73d9f21f9521a4ade6b7d26a
treece41a46f1b4f4d7669e80ad770ee8e1d766ebb77
parent1a270e5039adb18cb35a7e250a85b3138055319f
Bluetooth: Fix race condition in hci_release_sock()

commit 11eb85ec42dc8c7a7ec519b90ccf2eeae9409de8 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/bluetooth/hci_sock.c