[SECURITY PATCH 07/28] font: Do not load more than one NAME section

[Daniel Kiper]

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>
---
 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 5edb477ac..d09bb38d8 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;
-- 
2.11.0