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malloc: Use overflow checking primitives where we do complex allocations

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This attempts to fix the places where we do the following where
arithmetic_expr may include unvalidated data:

  X = grub_malloc(arithmetic_expr);

It accomplishes this by doing the arithmetic ahead of time using grub_add(),
grub_sub(), grub_mul() and testing for overflow before proceeding.

Among other issues, this fixes:
  - allocation of integer overflow in grub_video_bitmap_create()
    reported by Chris Coulson,
  - allocation of integer overflow in grub_png_decode_image_header()
    reported by Chris Coulson,
  - allocation of integer overflow in grub_squash_read_symlink()
    reported by Chris Coulson,
  - allocation of integer overflow in grub_ext2_read_symlink()
    reported by Chris Coulson,
  - allocation of integer overflow in read_section_as_string()
    reported by Chris Coulson.

Fixes: CVE-2020-14309, CVE-2020-14310, CVE-2020-14311

Signed-off-by: Peter Jones <pjones@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Peter Jones 2020-06-15 12:28:27 -04:00 • committed by Daniel Kiper
parent f725fa7cb2
commit 3f05d693d1
23 changed files with 382 additions and 113 deletions
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7
grub-core/font/font.c
View file

@ -30,6 +30,7 @@
#include <grub/unicode.h>
#include <grub/fontformat.h>
#include <grub/env.h>
#include <grub/safemath.h>
GRUB_MOD_LICENSE ("GPLv3+");
@ -360,9 +361,13 @@ static char *
read_section_as_string (struct font_file_section *section)
{
char *str;
grub_size_t sz;
grub_ssize_t ret;
str = grub_malloc (section->length + 1);
if (grub_add (section->length, 1, &sz))
return NULL;
str = grub_malloc (sz);
if (!str)
return 0;