From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Darren Kenny <darren.kenny@oracle.com>
Date: Fri, 27 Nov 2020 15:10:26 +0000
Subject: [PATCH] net/net: Fix possible dereference to of a NULL pointer

It is always possible that grub_zalloc() could fail, so we should check for
a NULL return. Otherwise we run the risk of dereferencing a NULL pointer.

Fixes: CID 296221

Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
 grub-core/net/net.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/grub-core/net/net.c b/grub-core/net/net.c
index 1fd104aea..a27c53eee 100644
--- a/grub-core/net/net.c
+++ b/grub-core/net/net.c
@@ -89,8 +89,13 @@ grub_net_link_layer_add_address (struct grub_net_card *card,
 
   /* Add sender to cache table.  */
   if (card->link_layer_table == NULL)
-    card->link_layer_table = grub_zalloc (LINK_LAYER_CACHE_SIZE
-					  * sizeof (card->link_layer_table[0]));
+    {
+      card->link_layer_table = grub_zalloc (LINK_LAYER_CACHE_SIZE
+					    * sizeof (card->link_layer_table[0]));
+      if (card->link_layer_table == NULL)
+	return;
+    }
+
   entry = &(card->link_layer_table[card->new_ll_entry]);
   entry->avail = 1;
   grub_memcpy (&entry->ll_address, ll, sizeof (entry->ll_address));