diff --git a/scripts/dtc/flattree.c b/scripts/dtc/flattree.c
index bd99fa2..ec14954 100644
--- a/scripts/dtc/flattree.c
+++ b/scripts/dtc/flattree.c
@@ -889,7 +889,7 @@
 
 	if (version >= 3) {
 		uint32_t size_str = fdt32_to_cpu(fdt->size_dt_strings);
-		if (off_str+size_str > totalsize)
+		if ((off_str+size_str < off_str) || (off_str+size_str > totalsize))
 			die("String table extends past total size\n");
 		inbuf_init(&strbuf, blob + off_str, blob + off_str + size_str);
 	} else {
@@ -898,7 +898,7 @@
 
 	if (version >= 17) {
 		size_dt = fdt32_to_cpu(fdt->size_dt_struct);
-		if (off_dt+size_dt > totalsize)
+		if ((off_dt+size_dt < off_dt) || (off_dt+size_dt > totalsize))
 			die("Structure block extends past total size\n");
 	}