ASoC: sigmadsp: Refuse to load firmware files with a non-supported version

Make sure to check the version field of the firmware header to make sure to
not accidentally try to parse a firmware file with a different layout.
Trying to do so can result in loading invalid firmware code to the device.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

sound/soc/codecs/sigmadsp.c

@@ -159,6 +159,13 @@ int _process_sigma_firmware(struct device *dev,
 		goto done;
 	}
 
+	if (ssfw_head->version != 1) {
+		dev_err(dev,
+			"Failed to load firmware: Invalid version %d. Supported firmware versions: 1\n",
+			ssfw_head->version);
+		goto done;
+	}
+
 	crc = crc32(0, fw->data + sizeof(*ssfw_head),
 			fw->size - sizeof(*ssfw_head));
 	pr_debug("%s: crc=%x\n", __func__, crc);