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>

5 files changed, 68 insertions, 34 deletions

diff --git a/drivers/net/wireless/rt2x00/rt2x00.h b/drivers/net/wireless/rt2x00/rt2x00.h
index 94fb571667f..84bd6f19acb 100644
--- a/drivers/net/wireless/rt2x00/rt2x00.h
+++ b/drivers/net/wireless/rt2x00/rt2x00.h
@@ -468,9 +468,10 @@ struct rt2x00lib_ops {
          */
         int (*probe_hw) (struct rt2x00_dev *rt2x00dev);
         char *(*get_firmware_name) (struct rt2x00_dev *rt2x00dev);
-        u16 (*get_firmware_crc) (const void *data, const size_t len);
-        int (*load_firmware) (struct rt2x00_dev *rt2x00dev, const void *data,
-                              const size_t len);
+        int (*check_firmware) (struct rt2x00_dev *rt2x00dev,
+                               const u8 *data, const size_t len);
+        int (*load_firmware) (struct rt2x00_dev *rt2x00dev,
+                              const u8 *data, const size_t len);
 
         /*
          * Device initialization/deinitialization handlers.
diff --git a/drivers/net/wireless/rt2x00/rt2x00firmware.c b/drivers/net/wireless/rt2x00/rt2x00firmware.c
index 2a7e8bc0016..d2deea2f267 100644
--- a/drivers/net/wireless/rt2x00/rt2x00firmware.c
+++ b/drivers/net/wireless/rt2x00/rt2x00firmware.c
@@ -35,7 +35,6 @@ static int rt2x00lib_request_firmware(struct rt2x00_dev *rt2x00dev)
         const struct firmware *fw;
         char *fw_name;
         int retval;
-        u16 crc;
 
         /*
          * Read correct firmware from harddisk.
@@ -61,16 +60,26 @@ static int rt2x00lib_request_firmware(struct rt2x00_dev *rt2x00dev)
                 return -ENOENT;
         }
 
-        crc = rt2x00dev->ops->lib->get_firmware_crc(fw->data, fw->size);
-        if (crc != (fw->data[fw->size - 2] << 8 | fw->data[fw->size - 1])) {
-                ERROR(rt2x00dev, "Firmware checksum error.\n");
-                retval = -ENOENT;
-                goto exit;
-        }
-
         INFO(rt2x00dev, "Firmware detected - version: %d.%d.\n",
              fw->data[fw->size - 4], fw->data[fw->size - 3]);
 
+        retval = rt2x00dev->ops->lib->check_firmware(rt2x00dev, fw->data, fw->size);
+        switch (retval) {
+        case FW_OK:
+                break;
+        case FW_BAD_CRC:
+                ERROR(rt2x00dev, "Firmware checksum error.\n");
+                goto exit;
+        case FW_BAD_LENGTH:
+                ERROR(rt2x00dev,
+                      "Invalid firmware file length (len=%zu)\n", fw->size);
+                goto exit;
+        case FW_BAD_VERSION:
+                ERROR(rt2x00dev,
+                      "Current firmware does not support detected chipset.\n");
+                goto exit;
+        };
+
         rt2x00dev->fw = fw;
 
         return 0;
@@ -78,7 +87,7 @@ static int rt2x00lib_request_firmware(struct rt2x00_dev *rt2x00dev)
 exit:
         release_firmware(fw);
 
-        return retval;
+        return -ENOENT;
 }
 
 int rt2x00lib_load_firmware(struct rt2x00_dev *rt2x00dev)
diff --git a/drivers/net/wireless/rt2x00/rt2x00reg.h b/drivers/net/wireless/rt2x00/rt2x00reg.h
index 9ddc2d07eef..861322d97fc 100644
--- a/drivers/net/wireless/rt2x00/rt2x00reg.h
+++ b/drivers/net/wireless/rt2x00/rt2x00reg.h
@@ -135,6 +135,16 @@ enum rate_modulation {
 };
 
 /*
+ * Firmware validation error codes
+ */
+enum firmware_errors {
+        FW_OK,
+        FW_BAD_CRC,
+        FW_BAD_LENGTH,
+        FW_BAD_VERSION,
+};
+
+/*
  * Register handlers.
  * We store the position of a register field inside a field structure,
  * This will simplify the process of setting and reading a certain field
diff --git a/drivers/net/wireless/rt2x00/rt61pci.c b/drivers/net/wireless/rt2x00/rt61pci.c
index c7ad1b3d476..0be147f364e 100644
--- a/drivers/net/wireless/rt2x00/rt61pci.c
+++ b/drivers/net/wireless/rt2x00/rt61pci.c
@@ -1176,34 +1176,41 @@ static char *rt61pci_get_firmware_name(struct rt2x00_dev *rt2x00dev)
         return fw_name;
 }
 
-static u16 rt61pci_get_firmware_crc(const void *data, const size_t len)
+static int rt61pci_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 8kb firmware files.
+         */
+        if (len != 8192)
+                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 rt61pci_load_firmware(struct rt2x00_dev *rt2x00dev, const void *data,
-                                 const size_t len)
+static int rt61pci_load_firmware(struct rt2x00_dev *rt2x00dev,
+                                 const u8 *data, const size_t len)
 {
         int i;
         u32 reg;
 
-        if (len != 8192) {
-                ERROR(rt2x00dev, "Invalid firmware file length (len=%zu)\n", len);
-                return -ENOENT;
-        }
-
         /*
          * Wait for stable hardware.
          */
@@ -2750,7 +2757,7 @@ static const struct rt2x00lib_ops rt61pci_rt2x00_ops = {
         .irq_handler            = rt61pci_interrupt,
         .probe_hw               = rt61pci_probe_hw,
         .get_firmware_name      = rt61pci_get_firmware_name,
-        .get_firmware_crc       = rt61pci_get_firmware_crc,
+        .check_firmware         = rt61pci_check_firmware,
         .load_firmware          = rt61pci_load_firmware,
         .initialize             = rt2x00pci_initialize,
         .uninitialize           = rt2x00pci_uninitialize,
diff --git a/drivers/net/wireless/rt2x00/rt73usb.c b/drivers/net/wireless/rt2x00/rt73usb.c
index 24e97b341cf..be791a43c05 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,