grub2/0431-script-execute-Don-t-crash-on-a-for-loop-with-no-ite.patch

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Daniel Axtens <dja@axtens.net>
Date: Fri, 22 Jan 2021 16:18:26 +1100
Subject: [PATCH] script/execute: Don't crash on a "for" loop with no items
The following crashes the parser:
for x in; do
0
done
This is because grub_script_arglist_to_argv() doesn't consider the
possibility that arglist is NULL. Catch that explicitly.
This avoids a NULL pointer dereference.
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/script/execute.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/grub-core/script/execute.c b/grub-core/script/execute.c
index 17f4dcab2..266d99ed3 100644
--- a/grub-core/script/execute.c
+++ b/grub-core/script/execute.c
@@ -658,6 +658,9 @@ grub_script_arglist_to_argv (struct grub_script_arglist *arglist,
struct grub_script_arg *arg = 0;
struct grub_script_argv result = { 0, 0, 0 };
+ if (arglist == NULL)
+ return 1;
+
for (; arglist && arglist->arg; arglist = arglist->next)
{
if (grub_script_argv_next (&result))