From: Vladis Dronov <vdronov@xxxxxxxxxx> commit b36a1552d7319bbfd5cf7f08726c23c5c66d4f73 upstream. Certain ttys operations (pty_unix98_ops) lack tiocmget() and tiocmset() functions which are called by the certain HCI UART protocols (hci_ath, hci_bcm, hci_intel, hci_mrvl, hci_qca) via hci_uart_set_flow_control() or directly. This leads to an execution at NULL and can be triggered by an unprivileged user. Fix this by adding a helper function and a check for the missing tty operations in the protocols code. This fixes CVE-2019-10207. The Fixes: lines list commits where calls to tiocm[gs]et() or hci_uart_set_flow_control() were added to the HCI UART protocols. Link: https://syzkaller.appspot.com/bug?id=1b42faa2848963564a5b1b7f8c837ea7b55ffa50 Reported-by: syzbot+79337b501d6aa974d0f6@xxxxxxxxxxxxxxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx # v2.6.36+ Fixes: b3190df62861 ("Bluetooth: Support for Atheros AR300x serial chip") Fixes: 118612fb9165 ("Bluetooth: hci_bcm: Add suspend/resume PM functions") Fixes: ff2895592f0f ("Bluetooth: hci_intel: Add Intel baudrate configuration support") Fixes: 162f812f23ba ("Bluetooth: hci_uart: Add Marvell support") Fixes: fa9ad876b8e0 ("Bluetooth: hci_qca: Add support for Qualcomm Bluetooth chip wcn3990") Signed-off-by: Vladis Dronov <vdronov@xxxxxxxxxx> Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx> Reviewed-by: Yu-Chen, Cho <acho@xxxxxxxx> Tested-by: Yu-Chen, Cho <acho@xxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/bluetooth/hci_ath.c | 3 +++ drivers/bluetooth/hci_bcm.c | 3 +++ drivers/bluetooth/hci_intel.c | 3 +++ drivers/bluetooth/hci_ldisc.c | 9 +++++++++ drivers/bluetooth/hci_uart.h | 1 + 5 files changed, 19 insertions(+) --- a/drivers/bluetooth/hci_ath.c +++ b/drivers/bluetooth/hci_ath.c @@ -101,6 +101,9 @@ static int ath_open(struct hci_uart *hu) BT_DBG("hu %p", hu); + if (!hci_uart_has_flow_control(hu)) + return -EOPNOTSUPP; + ath = kzalloc(sizeof(*ath), GFP_KERNEL); if (!ath) return -ENOMEM; --- a/drivers/bluetooth/hci_bcm.c +++ b/drivers/bluetooth/hci_bcm.c @@ -279,6 +279,9 @@ static int bcm_open(struct hci_uart *hu) bt_dev_dbg(hu->hdev, "hu %p", hu); + if (!hci_uart_has_flow_control(hu)) + return -EOPNOTSUPP; + bcm = kzalloc(sizeof(*bcm), GFP_KERNEL); if (!bcm) return -ENOMEM; --- a/drivers/bluetooth/hci_intel.c +++ b/drivers/bluetooth/hci_intel.c @@ -407,6 +407,9 @@ static int intel_open(struct hci_uart *h BT_DBG("hu %p", hu); + if (!hci_uart_has_flow_control(hu)) + return -EOPNOTSUPP; + intel = kzalloc(sizeof(*intel), GFP_KERNEL); if (!intel) return -ENOMEM; --- a/drivers/bluetooth/hci_ldisc.c +++ b/drivers/bluetooth/hci_ldisc.c @@ -257,6 +257,15 @@ static int hci_uart_send_frame(struct hc return 0; } +/* Check the underlying device or tty has flow control support */ +bool hci_uart_has_flow_control(struct hci_uart *hu) +{ + if (hu->tty->driver->ops->tiocmget && hu->tty->driver->ops->tiocmset) + return true; + + return false; +} + /* Flow control or un-flow control the device */ void hci_uart_set_flow_control(struct hci_uart *hu, bool enable) { --- a/drivers/bluetooth/hci_uart.h +++ b/drivers/bluetooth/hci_uart.h @@ -105,6 +105,7 @@ int hci_uart_tx_wakeup(struct hci_uart * int hci_uart_init_ready(struct hci_uart *hu); void hci_uart_init_tty(struct hci_uart *hu); void hci_uart_set_baudrate(struct hci_uart *hu, unsigned int speed); +bool hci_uart_has_flow_control(struct hci_uart *hu); void hci_uart_set_flow_control(struct hci_uart *hu, bool enable); void hci_uart_set_speeds(struct hci_uart *hu, unsigned int init_speed, unsigned int oper_speed);
