[PATCH 2/3] rsi: check length before USB read/write register

[Amitkumar Karwar]

From: Amitkumar Karwar <amit.kar...@redpinesignals.com>

These checks are required. Otherwise we may end up getting
memory corruption if invalid length is passed.

Fixes: b97e9b94ad75c ("rsi: Add new host interface operations")
Signed-off-by: Amitkumar Karwar <amit.kar...@redpinesignals.com>
---
 drivers/net/wireless/rsi/rsi_91x_usb.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/wireless/rsi/rsi_91x_usb.c 
b/drivers/net/wireless/rsi/rsi_91x_usb.c
index 99a520a..3d33ce9 100644
--- a/drivers/net/wireless/rsi/rsi_91x_usb.c
+++ b/drivers/net/wireless/rsi/rsi_91x_usb.c
@@ -166,6 +166,9 @@ static int rsi_usb_reg_read(struct usb_device *usbdev,
        if (!buf)
                return status;
 
+       if (len > RSI_USB_CTRL_BUF_SIZE)
+               return -EINVAL;
+
        status = usb_control_msg(usbdev,
                                 usb_rcvctrlpipe(usbdev, 0),
                                 USB_VENDOR_REGISTER_READ,
@@ -208,6 +211,9 @@ static int rsi_usb_reg_write(struct usb_device *usbdev,
        if (!usb_reg_buf)
                return status;
 
+       if (len > RSI_USB_CTRL_BUF_SIZE)
+               return -EINVAL;
+
        usb_reg_buf[0] = (value & 0x00ff);
        usb_reg_buf[1] = (value & 0xff00) >> 8;
        usb_reg_buf[2] = 0x0;
-- 
2.7.4