rimage: propagate verification result to the exit code

Verify mode logged signature failures and a missing header but returned success,
so callers using the exit code as a gate would accept a tampered image. Return
an error when no header is found and propagate the verification result.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>

Author: lrgirdwo

tools/rimage/src/manifest.c

@@ -1688,9 +1688,13 @@ int verify_image(struct image *image)
 	/* no header found */
 	fprintf(stderr, "error: could not find valid CSE header $CPD in %s\n",
 		image->verify_file);
+	ret = -EINVAL;
 out:
 	fclose(in_file);
-	return 0;
+	/* propagate verification result so callers (and the exit code) can
+	 * detect a failed/missing verification instead of always seeing success
+	 */
+	return ret;
 }