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 21:22:42 +0000 (21:22 +0000)
commit07d00820bf987985e04a1e9abf63bc1b1aff3aa5
treefe18d7f2f27498a80fe05d279ffb73349785eb3f
parentf39406a925b09130b5baa53bb09d416ef64e38a7
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