grub2/0198-blscfg-return-NULL-instead-of-a-zero-length-array-in.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Mon, 16 Mar 2020 13:51:45 +0100
Subject: [PATCH] blscfg: return NULL instead of a zero-length array in
 bls_make_list()

The bls_make_list() function returns a list of all the values for a given
key and if there is none a NULL pointer should be returned. But currently
is returnin a zero-length array instead.

This makes the callers to wrongly assume that there are values for a key
and populate wrong menu entries. For example menu entries are populated
with an initrd command even if there is no initrd fiel in the BLS file.

Resolves: rhbz#1806022

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
---
 grub-core/commands/blscfg.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/grub-core/commands/blscfg.c b/grub-core/commands/blscfg.c
index aa4e624905e..df6947f58cd 100644
--- a/grub-core/commands/blscfg.c
+++ b/grub-core/commands/blscfg.c
@@ -600,6 +600,12 @@ static char **bls_make_list (struct bls_entry *entry, const char *key, int *num)
       list[nlist] = NULL;
   }
 
+  if (!nlist)
+    {
+      grub_free (list);
+      return NULL;
+    }
+
   if (num)
     *num = nlist;