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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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13
grub-core/video/readers/png.c
View file

@ -23,6 +23,7 @@
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/bufio.h>
#include <grub/safemath.h>
GRUB_MOD_LICENSE ("GPLv3+");
@ -301,9 +302,17 @@ grub_png_decode_image_header (struct grub_png_data *data)
data->bpp <<= 1;
data->color_bits = color_bits;
data->row_bytes = data->image_width * data->bpp;
if (grub_mul (data->image_width, data->bpp, &data->row_bytes))
return grub_error (GRUB_ERR_OUT_OF_RANGE, N_("overflow is detected"));
if (data->color_bits <= 4)
data->row_bytes = (data->image_width * data->color_bits + 7) / 8;
{
if (grub_mul (data->image_width, data->color_bits + 7, &data->row_bytes))
return grub_error (GRUB_ERR_OUT_OF_RANGE, N_("overflow is detected"));
data->row_bytes >>= 3;
}
#ifndef GRUB_CPU_WORDS_BIGENDIAN
if (data->is_16bit || data->is_gray || data->is_palette)