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font: Fix integer overflow in ensure_comb_space()

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In fact it can't overflow at all because glyph_id->ncomb is only 8-bit
wide. But let's keep safe if somebody changes the width of glyph_id->ncomb
in the future. This patch also fixes the inconsistency between
render_max_comb_glyphs and render_combining_glyphs when grub_malloc()
returns NULL.

Signed-off-by: Zhang Boyang <zhangboyang.id@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Zhang Boyang 2022-08-05 02:27:05 +08:00 committed by Steve McIntyre
parent abce8a8ff6
commit 96409d679a
2 changed files with 57 additions and 5 deletions
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48
debian/patches/cve_2022_2601/0006-font-Fix-integer-overflow-in-ensure_comb_space.patch vendored Normal file
View File

@ -0,0 +1,48 @@
From b2740b7e4a03bb8331d48b54b119afea76bb9d5f Mon Sep 17 00:00:00 2001
From: Zhang Boyang <zhangboyang.id@gmail.com>
Date: Fri, 5 Aug 2022 02:27:05 +0800
Subject: [PATCH 06/14] font: Fix integer overflow in ensure_comb_space()
In fact it can't overflow at all because glyph_id->ncomb is only 8-bit
wide. But let's keep safe if somebody changes the width of glyph_id->ncomb
in the future. This patch also fixes the inconsistency between
render_max_comb_glyphs and render_combining_glyphs when grub_malloc()
returns NULL.
Signed-off-by: Zhang Boyang <zhangboyang.id@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/font/font.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/grub-core/font/font.c b/grub-core/font/font.c
index a8576ffec..9e3e0a94e 100644
--- a/grub-core/font/font.c
+++ b/grub-core/font/font.c
@@ -1468,14 +1468,18 @@ ensure_comb_space (const struct grub_unicode_glyph *glyph_id)
if (glyph_id->ncomb <= render_max_comb_glyphs)
return;
- render_max_comb_glyphs = 2 * glyph_id->ncomb;
- if (render_max_comb_glyphs < 8)
+ if (grub_mul (glyph_id->ncomb, 2, &render_max_comb_glyphs))
+ render_max_comb_glyphs = 0;
+ if (render_max_comb_glyphs > 0 && render_max_comb_glyphs < 8)
render_max_comb_glyphs = 8;
grub_free (render_combining_glyphs);
- render_combining_glyphs = grub_malloc (render_max_comb_glyphs
- * sizeof (render_combining_glyphs[0]));
+ render_combining_glyphs = (render_max_comb_glyphs > 0) ?
+ grub_calloc (render_max_comb_glyphs, sizeof (render_combining_glyphs[0])) : NULL;
if (!render_combining_glyphs)
- grub_errno = 0;
+ {
+ render_max_comb_glyphs = 0;
+ grub_errno = GRUB_ERR_NONE;
+ }
}
int
--
2.30.2

14
grub-core/font/font.c
View File

@ -1468,14 +1468,18 @@ ensure_comb_space (const struct grub_unicode_glyph *glyph_id)
if (glyph_id->ncomb <= render_max_comb_glyphs)
return;
render_max_comb_glyphs = 2 * glyph_id->ncomb;
if (render_max_comb_glyphs < 8)
if (grub_mul (glyph_id->ncomb, 2, &render_max_comb_glyphs))
render_max_comb_glyphs = 0;
if (render_max_comb_glyphs > 0 && render_max_comb_glyphs < 8)
render_max_comb_glyphs = 8;
grub_free (render_combining_glyphs);
render_combining_glyphs = grub_malloc (render_max_comb_glyphs
* sizeof (render_combining_glyphs[0]));
render_combining_glyphs = (render_max_comb_glyphs > 0) ?
grub_calloc (render_max_comb_glyphs, sizeof (render_combining_glyphs[0])) : NULL;
if (!render_combining_glyphs)
grub_errno = 0;
{
render_max_comb_glyphs = 0;
grub_errno = GRUB_ERR_NONE;
}
}
int