watchdog: ziirave_wdt: Don't read out more than 'len' firmware bytes

We only compare first 'len' bytes of read firmware, so we don't need
to read more that that.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Rick Ramstetter <rick@anteaterllc.com>
Cc: linux-watchdog@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20190812200906.31344-14-andrew.smirnov@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_wdt.c
index 4b95467bf2396adba9548b70aafea6a3182ebefe..f05095b08016de3023b21b6b17ff8499d402a4a8 100644 (file)
--- a/drivers/watchdog/ziirave_wdt.c
+++ b/drivers/watchdog/ziirave_wdt.c
@@ -318,6 +318,8 @@ static int ziirave_firm_verify(struct watchdog_device *wdd,
        u16 addr;
 
        for (rec = (void *)fw->data; rec; rec = ihex_next_binrec(rec)) {
+               const u16 len = be16_to_cpu(rec->len);
+
                addr = (be32_to_cpu(rec->addr) & 0xffff) >> 1;
                if (addr < ZIIRAVE_FIRM_FLASH_MEMORY_START ||
                    addr > ZIIRAVE_FIRM_FLASH_MEMORY_END)
@@ -331,7 +333,7 @@ static int ziirave_firm_verify(struct watchdog_device *wdd,
                        return ret;
                }
 
-               for (i = 0; i < ARRAY_SIZE(data); i++) {
+               for (i = 0; i < len; i++) {
                        ret = i2c_smbus_read_byte_data(client,
                                                ZIIRAVE_CMD_DOWNLOAD_READ_BYTE);
                        if (ret < 0) {
@@ -342,7 +344,7 @@ static int ziirave_firm_verify(struct watchdog_device *wdd,
                        data[i] = ret;
                }
 
-               if (memcmp(data, rec->data, be16_to_cpu(rec->len))) {
+               if (memcmp(data, rec->data, len)) {
                        dev_err(&client->dev,
                                "Firmware mismatch at address 0x%04x\n", addr);
                        return -EINVAL;