grub2/0231-font-Do-not-load-more-than-one-NAME-section.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Daniel Kiper <daniel.kiper@oracle.com>
Date: Tue, 7 Jul 2020 15:36:26 +0200
Subject: [PATCH] font: Do not load more than one NAME section

The GRUB font file can have one NAME section only. Though if somebody
crafts a broken font file with many NAME sections and loads it then the
GRUB leaks memory. So, prevent against that by loading first NAME
section and failing in controlled way on following one.

Reported-by: Chris Coulson <chris.coulson@canonical.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Reviewed-by: Jan Setje-Eilers <jan.setjeeilers@oracle.com>
Upstream-commit-id: 482814113dc
---
 grub-core/font/font.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/grub-core/font/font.c b/grub-core/font/font.c
index 5edb477ac2e..d09bb38d896 100644
--- a/grub-core/font/font.c
+++ b/grub-core/font/font.c
@@ -532,6 +532,12 @@ grub_font_load (const char *filename)
       if (grub_memcmp (section.name, FONT_FORMAT_SECTION_NAMES_FONT_NAME,
 		       sizeof (FONT_FORMAT_SECTION_NAMES_FONT_NAME) - 1) == 0)
 	{
+	  if (font->name != NULL)
+	    {
+	      grub_error (GRUB_ERR_BAD_FONT, "invalid font file: too many NAME sections");
+	      goto fail;
+	    }
+
 	  font->name = read_section_as_string (&section);
 	  if (!font->name)
 	    goto fail;