[PATCH] Bluetooth: hci_uart: check for missing tty operations in protocol handlers

[Vladis Dronov <vdronov@redhat.com>]

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 check for the missing tty
operations to the protocols which use them.

This fixes CVE-2019-10207.

Link: https://syzkaller.appspot.com/bug?id=1b42faa2848963564a5b1b7f8c837ea7b55ffa50
Reported-by: syzbot+79337b501d6aa974d0f6@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org # 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@redhat.com>
---
 drivers/bluetooth/hci_ath.c   | 3 +++
 drivers/bluetooth/hci_bcm.c   | 5 +++++
 drivers/bluetooth/hci_intel.c | 3 +++
 drivers/bluetooth/hci_mrvl.c  | 3 +++
 drivers/bluetooth/hci_qca.c   | 4 ++++
 5 files changed, 18 insertions(+)

diff --git a/drivers/bluetooth/hci_ath.c b/drivers/bluetooth/hci_ath.c
index a55be205b91a..99df8a13e47e 100644
--- a/drivers/bluetooth/hci_ath.c
+++ b/drivers/bluetooth/hci_ath.c
@@ -98,6 +98,9 @@ static int ath_open(struct hci_uart *hu)
 
 	BT_DBG("hu %p", hu);
 
+	if (!hu->tty->driver->ops->tiocmget || !hu->tty->driver->ops->tiocmset)
+		return -ENOTSUPP;
+
 	ath = kzalloc(sizeof(*ath), GFP_KERNEL);
 	if (!ath)
 		return -ENOMEM;
diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
index 8905ad2edde7..8c3e09cc341c 100644
--- a/drivers/bluetooth/hci_bcm.c
+++ b/drivers/bluetooth/hci_bcm.c
@@ -406,6 +406,11 @@ static int bcm_open(struct hci_uart *hu)
 
 	bt_dev_dbg(hu->hdev, "hu %p", hu);
 
+#ifdef CONFIG_PM
+	if (!hu->tty->driver->ops->tiocmget || !hu->tty->driver->ops->tiocmset)
+		return -ENOTSUPP;
+#endif
+
 	bcm = kzalloc(sizeof(*bcm), GFP_KERNEL);
 	if (!bcm)
 		return -ENOMEM;
diff --git a/drivers/bluetooth/hci_intel.c b/drivers/bluetooth/hci_intel.c
index 207bae5e0d46..a314882a1cac 100644
--- a/drivers/bluetooth/hci_intel.c
+++ b/drivers/bluetooth/hci_intel.c
@@ -391,6 +391,9 @@ static int intel_open(struct hci_uart *hu)
 
 	BT_DBG("hu %p", hu);
 
+	if (!hu->tty->driver->ops->tiocmget || !hu->tty->driver->ops->tiocmset)
+		return -ENOTSUPP;
+
 	intel = kzalloc(sizeof(*intel), GFP_KERNEL);
 	if (!intel)
 		return -ENOMEM;
diff --git a/drivers/bluetooth/hci_mrvl.c b/drivers/bluetooth/hci_mrvl.c
index f98e5cc343b2..4ee27c8d8679 100644
--- a/drivers/bluetooth/hci_mrvl.c
+++ b/drivers/bluetooth/hci_mrvl.c
@@ -59,6 +59,9 @@ static int mrvl_open(struct hci_uart *hu)
 
 	BT_DBG("hu %p", hu);
 
+	if (!hu->tty->driver->ops->tiocmget || !hu->tty->driver->ops->tiocmset)
+		return -ENOTSUPP;
+
 	mrvl = kzalloc(sizeof(*mrvl), GFP_KERNEL);
 	if (!mrvl)
 		return -ENOMEM;
diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index 9a5c9c1f9484..a65c202e8995 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -28,6 +28,7 @@
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
 #include <linux/serdev.h>
+#include <linux/tty.h>
 #include <asm/unaligned.h>
 
 #include <net/bluetooth/bluetooth.h>
@@ -473,6 +474,9 @@ static int qca_open(struct hci_uart *hu)
 
 	BT_DBG("hu %p qca_open", hu);
 
+	if (!hu->tty->driver->ops->tiocmget || !hu->tty->driver->ops->tiocmset)
+		return -ENOTSUPP;
+
 	qca = kzalloc(sizeof(struct qca_data), GFP_KERNEL);
 	if (!qca)
 		return -ENOMEM;
-- 
2.20.1