From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Darren Kenny <darren.kenny@oracle.com>
Date: Fri, 23 Oct 2020 09:49:59 +0000
Subject: [PATCH] kern/partition: Check for NULL before dereferencing input
 string

There is the possibility that the value of str comes from an external
source and continuing to use it before ever checking its validity is
wrong. So, needs fixing.

Additionally, drop unneeded part initialization.

Fixes: CID 292444

Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
 grub-core/kern/partition.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/grub-core/kern/partition.c b/grub-core/kern/partition.c
index e499147cbcb..b10a184e3fa 100644
--- a/grub-core/kern/partition.c
+++ b/grub-core/kern/partition.c
@@ -109,11 +109,14 @@ grub_partition_map_probe (const grub_partition_map_t partmap,
 grub_partition_t
 grub_partition_probe (struct grub_disk *disk, const char *str)
 {
-  grub_partition_t part = 0;
+  grub_partition_t part;
   grub_partition_t curpart = 0;
   grub_partition_t tail;
   const char *ptr;
 
+  if (str == NULL)
+    return 0;
+
   part = tail = disk->partition;
 
   for (ptr = str; *ptr;)