[PATCH 3/3] Bluetooth: btusb: Fix short read errors in btusb_qca_send_vendor_req()

[Greg Kroah-Hartman]

If btusb_qca_send_vendor_req() gets a "short" read from a device, it
will accidentally treat that as a "real" read and populate the returned
value with some unknown and probably totally invalid data.

Fix this logic error up by calling usb_control_msg_recv() which
guarantees a "full" read happens, and then simplify the error checking
for when btusb_qca_send_vendor_req() is called.

Cc: stable <stable at kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
 drivers/bluetooth/btusb.c | 30 +++++++++---------------------
 1 file changed, 9 insertions(+), 21 deletions(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 8f7ed469cac6..184e95c1625e 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -3424,28 +3424,16 @@ static const char *qca_get_fw_subdirectory(const struct qca_version *ver)
 static int btusb_qca_send_vendor_req(struct usb_device *udev, u8 request,
 				     void *data, u16 size)
 {
-	int pipe, err;
-	u8 *buf;
-
-	buf = kmalloc(size, GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
+	int err;
 
 	/* Found some of USB hosts have IOT issues with ours so that we should
 	 * not wait until HCI layer is ready.
 	 */
-	pipe = usb_rcvctrlpipe(udev, 0);
-	err = usb_control_msg(udev, pipe, request, USB_TYPE_VENDOR | USB_DIR_IN,
-			      0, 0, buf, size, USB_CTRL_GET_TIMEOUT);
-	if (err < 0) {
+	err = usb_control_msg_recv(udev, 0, request, USB_TYPE_VENDOR | USB_DIR_IN,
+				   0, 0, data, size, USB_CTRL_GET_TIMEOUT,
+				   GFP_KERNEL);
+	if (err)
 		dev_err(&udev->dev, "Failed to access otp area (%d)", err);
-		goto done;
-	}
-
-	memcpy(data, buf, size);
-
-done:
-	kfree(buf);
 
 	return err;
 }
@@ -3652,7 +3640,7 @@ static bool btusb_qca_need_patch(struct usb_device *udev)
 	struct qca_version ver;
 
 	if (btusb_qca_send_vendor_req(udev, QCA_GET_TARGET_VERSION, &ver,
-				      sizeof(ver)) < 0)
+				      sizeof(ver)))
 		return false;
 	/* only low ROM versions need patches */
 	return !(le32_to_cpu(ver.rom_version) & ~0xffffU);
@@ -3670,7 +3658,7 @@ static int btusb_setup_qca(struct hci_dev *hdev)
 
 	err = btusb_qca_send_vendor_req(udev, QCA_GET_TARGET_VERSION, &ver,
 					sizeof(ver));
-	if (err < 0)
+	if (err)
 		return err;
 
 	ver_rom = le32_to_cpu(ver.rom_version);
@@ -3693,7 +3681,7 @@ static int btusb_setup_qca(struct hci_dev *hdev)
 
 	err = btusb_qca_send_vendor_req(udev, QCA_CHECK_STATUS, &status,
 					sizeof(status));
-	if (err < 0)
+	if (err)
 		return err;
 
 	if (!(status & QCA_PATCH_UPDATED)) {
@@ -3704,7 +3692,7 @@ static int btusb_setup_qca(struct hci_dev *hdev)
 
 	err = btusb_qca_send_vendor_req(udev, QCA_GET_TARGET_VERSION, &ver,
 					sizeof(ver));
-	if (err < 0)
+	if (err)
 		return err;
 
 	btdata->qca_dump.fw_version = le32_to_cpu(ver.patch_version);

-- 
2.55.0