rt2x00: Validate firmware in driver

The get_firmware_crc() callback function isn't flexible
enough when dealing with multiple firmware versions.
It might in some cases be possible that the firmware
file contains multiple CRC checksums.

Create the check_firmware() callback function where the driver
has complete freedom in how to validate the firmware.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 18 insertions, 11 deletions

diff --git a/drivers/net/wireless/rt2x00/rt73usb.c b/drivers/net/wireless/rt2x00/rt73usb.c
index 24e97b341cf8..be791a43c054 100644
--- a/drivers/net/wireless/rt2x00/rt73usb.c
+++ b/drivers/net/wireless/rt2x00/rt73usb.c
@@ -1061,35 +1061,42 @@ static char *rt73usb_get_firmware_name(struct rt2x00_dev *rt2x00dev)
         return FIRMWARE_RT2571;
 }
 
-static u16 rt73usb_get_firmware_crc(const void *data, const size_t len)
+static int rt73usb_check_firmware(struct rt2x00_dev *rt2x00dev,
+                                  const u8 *data, const size_t len)
 {
+        u16 fw_crc;
         u16 crc;
 
         /*
-         * Use the crc itu-t algorithm.
+         * Only support 2kb firmware files.
+         */
+        if (len != 2048)
+                return FW_BAD_LENGTH;
+
+        /*
          * The last 2 bytes in the firmware array are the crc checksum itself,
          * this means that we should never pass those 2 bytes to the crc
          * algorithm.
          */
+        fw_crc = (data[len - 2] << 8 | data[len - 1]);
+
+        /*
+         * Use the crc itu-t algorithm.
+         */
         crc = crc_itu_t(0, data, len - 2);
         crc = crc_itu_t_byte(crc, 0);
         crc = crc_itu_t_byte(crc, 0);
 
-        return crc;
+        return (fw_crc == crc) ? FW_OK : FW_BAD_CRC;
 }
 
-static int rt73usb_load_firmware(struct rt2x00_dev *rt2x00dev, const void *data,
-                                 const size_t len)
+static int rt73usb_load_firmware(struct rt2x00_dev *rt2x00dev,
+                                 const u8 *data, const size_t len)
 {
         unsigned int i;
         int status;
         u32 reg;
 
-        if (len != 2048) {
-                ERROR(rt2x00dev, "Invalid firmware file length (len=%zu)\n", len);
-                return -ENOENT;
-        }
-
         /*
          * Wait for stable hardware.
          */
@@ -2278,7 +2285,7 @@ static const struct ieee80211_ops rt73usb_mac80211_ops = {
 static const struct rt2x00lib_ops rt73usb_rt2x00_ops = {
         .probe_hw               = rt73usb_probe_hw,
         .get_firmware_name      = rt73usb_get_firmware_name,
-        .get_firmware_crc       = rt73usb_get_firmware_crc,
+        .check_firmware         = rt73usb_check_firmware,
         .load_firmware          = rt73usb_load_firmware,
         .initialize             = rt2x00usb_initialize,
         .uninitialize           = rt2x00usb_uninitialize,