--- a/tagutils/tagutils-wav.c
+++ b/tagutils/tagutils-wav.c
@@ -100,7 +100,7 @@
 		//        isprint(hdr[3]) ? hdr[3] : '?',
 		//        block_len);
 
-		if(block_len < 0)
+		if(block_len > psong->file_size)
 		{
 			close(fd);
 			DPRINTF(E_WARN, L_SCANNER, "Bad block len: %s\n", filename);