From 22b77b87e10a3a6c9bb9885415bc9a9c678378e6 Mon Sep 17 00:00:00 2001

From: Zhang Boyang <zhangboyang.id@gmail.com>

Date: Fri, 28 Oct 2022 17:29:16 +0800

Subject: [PATCH 11/12] font: Assign null_font to glyphs in ascii_font_glyph[]

The calculations in blit_comb() need information from glyph's font, e.g.

grub_font_get_xheight(main_glyph->font). However, main_glyph->font is

NULL if main_glyph comes from ascii_font_glyph[]. Therefore

grub_font_get_*() crashes because of NULL pointer.

There is already a solution, the null_font. So, assign it to those glyphs

in ascii_font_glyph[].

Reported-by: Daniel Axtens <dja@axtens.net>

Signed-off-by: Zhang Boyang <zhangboyang.id@gmail.com>

Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

---

 grub-core/font/font.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/grub-core/font/font.c b/grub-core/font/font.c

index cf15dc2f9..3821937e6 100644

--- a/grub-core/font/font.c

+++ b/grub-core/font/font.c

@@ -137,7 +137,7 @@ ascii_glyph_lookup (grub_uint32_t code)

 	  ascii_font_glyph[current]->offset_x = 0;

 	  ascii_font_glyph[current]->offset_y = -2;

 	  ascii_font_glyph[current]->device_width = 8;

-	  ascii_font_glyph[current]->font = NULL;

+	  ascii_font_glyph[current]->font = &null_font;

 	  grub_memcpy (ascii_font_glyph[current]->bitmap,

 		       &ascii_bitmaps[current * ASCII_BITMAP_SIZE],

-- 

2.33.5