diff --git a/bin/ls/util.c b/bin/ls/util.c
index 4d1173d793d1..4f80c784f725 100644
--- a/bin/ls/util.c
+++ b/bin/ls/util.c
@@ -58,7 +58,7 @@ prcopy(src, dest, len)
 	int ch;
 
 	while (len--) {
-		ch = *src++;
+		ch = *src++ & 0xff;
 		*dest++ = isprint(ch) ? ch : '?';
 	}
 }