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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 Daniel Kiper
parent c51292274d
commit 23843fe894
1 changed files with 9 additions and 5 deletions
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14
grub-core/font/font.c
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@ -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