integ/grub/grub2/debian/patches/0020-video-readers-jpeg-Block-int-underflow-wild-pointer-.patch
Li Zhou 44f318a38d grub2/grub-efi: fix CVEs
Porting patches from grub2_2.06-3~deb11u1 to fix below CVEs:
CVE-2021-3695
CVE-2021-3696
CVE-2021-3697
CVE-2022-28733
CVE-2022-28734

The source code of grub2_2.06-3~deb11u1 is from:
https://snapshot.debian.org/archive/debian/20220807T030023Z/pool
/main/g/grub2/grub2_2.06-3~deb11u1.debian.tar.xz

The relationship between commits and CVEs is as below:
(1)CVE-2021-3695
commit <video/readers/png: Drop greyscale support to fix heap
out-of-bounds write>
(2)CVE-2021-3696
commit <video/readers/png: Avoid heap OOB R/W inserting huff table items>
(3)CVE-2021-3697
commit <video/readers/jpeg: Block int underflow -> wild pointer write>
(4)CVE-2022-28733
commit <net/ip: Do IP fragment maths safely>
(5)CVE-2022-28734
commit <net/http: Fix OOB write for split http headers>
commit <net/http: Error out on headers with LF without CR>

Test plan:
 - PASS: build grub2/grub-efi.
 - PASS: build-image and install and boot up on lab/qemu.
 - PASS: check that the "stx.N" version number is right for both
         bios(grub2 ver) and uefi(grub-efi ver) boot.

Partial-Bug: #2034119

Signed-off-by: Li Zhou <li.zhou@windriver.com>
Change-Id: Ia27b1ee225f13e9c4ad08a0828f93ea37f8d3dfb
2023-09-07 01:42:31 -04:00

80 lines
2.6 KiB
Diff

From a10c2350a766f9b315735931a49499a7e2c77bf3 Mon Sep 17 00:00:00 2001
From: Daniel Axtens <dja@axtens.net>
Date: Mon, 4 Sep 2023 16:32:43 +0800
Subject: [PATCH 3/6] video/readers/jpeg: Block int underflow -> wild pointer
write
Certain 1 px wide images caused a wild pointer write in
grub_jpeg_ycrcb_to_rgb(). This was caused because in grub_jpeg_decode_data(),
we have the following loop:
for (; data->r1 < nr1 && (!data->dri || rst);
data->r1++, data->bitmap_ptr += (vb * data->image_width - hb * nc1) * 3)
We did not check if vb * width >= hb * nc1.
On a 64-bit platform, if that turns out to be negative, it will underflow,
be interpreted as unsigned 64-bit, then be added to the 64-bit pointer, so
we see data->bitmap_ptr jump, e.g.:
0x6180_0000_0480 to
0x6181_0000_0498
^
~--- carry has occurred and this pointer is now far away from
any object.
On a 32-bit platform, it will decrement the pointer, creating a pointer
that won't crash but will overwrite random data.
Catch the underflow and error out.
Fixes: CVE-2021-3697
Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
[lz: Adapt the patch for context changes]
Signed-off-by: Li Zhou <li.zhou@windriver.com>
---
grub-core/video/readers/jpeg.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/grub-core/video/readers/jpeg.c b/grub-core/video/readers/jpeg.c
index 0eeea0e..fdaef18 100644
--- a/grub-core/video/readers/jpeg.c
+++ b/grub-core/video/readers/jpeg.c
@@ -23,6 +23,7 @@
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/bufio.h>
+#include <grub/safemath.h>
GRUB_MOD_LICENSE ("GPLv3+");
@@ -643,6 +644,7 @@ static grub_err_t
grub_jpeg_decode_data (struct grub_jpeg_data *data)
{
unsigned c1, vb, hb, nr1, nc1;
+ unsigned stride_a, stride_b, stride;
int rst = data->dri;
vb = 8 << data->log_vs;
@@ -654,8 +656,14 @@ grub_jpeg_decode_data (struct grub_jpeg_data *data)
return grub_error(GRUB_ERR_BAD_FILE_TYPE,
"jpeg: attempted to decode data before start of stream");
+ if (grub_mul(vb, data->image_width, &stride_a) ||
+ grub_mul(hb, nc1, &stride_b) ||
+ grub_sub(stride_a, stride_b, &stride))
+ return grub_error (GRUB_ERR_BAD_FILE_TYPE,
+ "jpeg: cannot decode image with these dimensions");
+
for (; data->r1 < nr1 && (!data->dri || rst);
- data->r1++, data->bitmap_ptr += (vb * data->image_width - hb * nc1) * 3)
+ data->r1++, data->bitmap_ptr += stride * 3)
for (c1 = 0; c1 < nc1 && (!data->dri || rst);
c1++, rst--, data->bitmap_ptr += hb * 3)
{
--
2.17.1