From: millert <millert@openbsd.org>
Date: Mon, 5 Jul 2021 13:41:46 +0000 (+0000)
Subject: Do not permit an empty list between "while" and "do".
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=4685f2425243bee1be89977409e0daafa2db3d6d;p=openbsd

Do not permit an empty list between "while" and "do".
This avoids a cpu loop for "while do done" and is consistent with
the behavior of AT&T ksh and most other shells.  OK jca@ halex@
---

diff --git a/bin/ksh/syn.c b/bin/ksh/syn.c
index 4d845d9eca5..5de47704dc6 100644
--- a/bin/ksh/syn.c
+++ b/bin/ksh/syn.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: syn.c,v 1.39 2018/04/24 08:25:16 kn Exp $	*/
+/*	$OpenBSD: syn.c,v 1.40 2021/07/05 13:41:46 millert Exp $	*/
 
 /*
  * shell parser (C version)
@@ -331,6 +331,8 @@ get_command(int cf)
 		nesting_push(&old_nesting, c);
 		t = newtp((c == WHILE) ? TWHILE : TUNTIL);
 		t->left = c_list(true);
+		if (t->left == NULL)
+			syntaxerr(NULL);
 		t->right = dogroup();
 		nesting_pop(&old_nesting);
 		break;