rt2x00: Restrict firmware file lengths

Add extra security to the drivers for firmware loading,
check the firmware file length before uploading it to
the hardware. Incorrect lengths might indicate a firmware
upgrade (which is not yet supported by the driver) or
otherwise incorrect firmware.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt61pci.c

@@ -1199,6 +1199,11 @@ static int rt61pci_load_firmware(struct rt2x00_dev *rt2x00dev, const void *data,
 	int i;
 	u32 reg;
 
+	if (len != 8192) {
+		ERROR(rt2x00dev, "Invalid firmware file length (len=%zu)\n", len);
+		return -ENOENT;
+	}
+
 	/*
 	 * Wait for stable hardware.
 	 */

drivers/net/wireless/rt2x00/rt73usb.c

@@ -1085,6 +1085,11 @@ static int rt73usb_load_firmware(struct rt2x00_dev *rt2x00dev, const void *data,
 	int status;
 	u32 reg;
 
+	if (len != 2048) {
+		ERROR(rt2x00dev, "Invalid firmware file length (len=%zu)\n", len);
+		return -ENOENT;
+	}
+
 	/*
 	 * Wait for stable hardware.
 	 */