diff options
| author | Jeremy Cline <jcline@redhat.com> | 2019-02-06 12:54:16 -0500 |
|---|---|---|
| committer | Marcel Holtmann <marcel@holtmann.org> | 2019-02-18 13:54:53 +0100 |
| commit | 32a7b4cbe93b0a0ef7e63d31ca69ce54736c4412 (patch) | |
| tree | 7d576c23965430a2d3b65ff5ec107e867f7e1e07 /drivers/bluetooth | |
| parent | 035a960e7a279a59d74585105dcd263559d74f24 (diff) | |
Bluetooth: hci_ldisc: Initialize hci_dev before open()
The hci_dev struct hdev is referenced in work queues and timers started
by open() in some protocols. This creates a race between the
initialization function and the work or timer which can result hdev
being dereferenced while it is still null.
The syzbot report contains a reliable reproducer which causes a null
pointer dereference of hdev in hci_uart_write_work() by making the
memory allocation for hdev fail.
To fix this, ensure hdev is valid from before calling a protocol's
open() until after calling a protocol's close().
Reported-by: syzbot+257790c15bcdef6fe00c@syzkaller.appspotmail.com
Signed-off-by: Jeremy Cline <jcline@redhat.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Diffstat (limited to 'drivers/bluetooth')
| -rw-r--r-- | drivers/bluetooth/hci_ldisc.c | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c index fbf7b4df23ab..4918fefc4a6f 100644 --- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -207,11 +207,11 @@ void hci_uart_init_work(struct work_struct *work) err = hci_register_dev(hu->hdev); if (err < 0) { BT_ERR("Can't register HCI device"); + clear_bit(HCI_UART_PROTO_READY, &hu->flags); + hu->proto->close(hu); hdev = hu->hdev; hu->hdev = NULL; hci_free_dev(hdev); - clear_bit(HCI_UART_PROTO_READY, &hu->flags); - hu->proto->close(hu); return; } @@ -616,6 +616,7 @@ static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data, static int hci_uart_register_dev(struct hci_uart *hu) { struct hci_dev *hdev; + int err; BT_DBG(""); @@ -659,11 +660,22 @@ static int hci_uart_register_dev(struct hci_uart *hu) else hdev->dev_type = HCI_PRIMARY; + /* Only call open() for the protocol after hdev is fully initialized as + * open() (or a timer/workqueue it starts) may attempt to reference it. + */ + err = hu->proto->open(hu); + if (err) { + hu->hdev = NULL; + hci_free_dev(hdev); + return err; + } + if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags)) return 0; if (hci_register_dev(hdev) < 0) { BT_ERR("Can't register HCI device"); + hu->proto->close(hu); hu->hdev = NULL; hci_free_dev(hdev); return -ENODEV; @@ -683,17 +695,12 @@ static int hci_uart_set_proto(struct hci_uart *hu, int id) if (!p) return -EPROTONOSUPPORT; - err = p->open(hu); - if (err) - return err; - hu->proto = p; set_bit(HCI_UART_PROTO_READY, &hu->flags); err = hci_uart_register_dev(hu); if (err) { clear_bit(HCI_UART_PROTO_READY, &hu->flags); - p->close(hu); return err; } |