integ/grub/grub-efi/debian/patches/0029-kern-efi-sb-Enforce-verification-of-font-files.patch
Li Zhou d10d6fb187 grub2/grub-efi: fix CVE-2022-2601/CVE-2022-3775
Porting patches from grub2_2.06-3~deb11u4 to fix
CVE-2022-2601/CVE-2022-3775.

The source code of grub2_2.06-3~deb11u4 is from:
https://snapshot.debian.org/archive/debian/20221124T030451Z/
pool/main/g/grub2/grub2_2.06-3~deb11u4.debian.tar.xz

Refer to above source code and this link for the fix:
https://lists.gnu.org/archive/html/grub-devel/2022-11/msg00059.html

The 1st patch in the list is for making proper context for the 14
patches of the 2 CVEs. No content changes for all the patches from
debian release.

We do this because grub2/grub-efi is ported from wrlinux for
secure boot bringing up.

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.

Closes-bug: 2020730

Signed-off-by: Li Zhou <li.zhou@windriver.com>
Change-Id: Ia6c58a2021a786ef92f760b3cfe035fbccedacf7
2023-06-01 06:08:44 -04:00

55 lines
2.1 KiB
Diff

From 630deb8c0d8b02b670ced4b7030414bcf17aa080 Mon Sep 17 00:00:00 2001
From: Zhang Boyang <zhangboyang.id@gmail.com>
Date: Sun, 14 Aug 2022 15:51:54 +0800
Subject: [PATCH 09/14] kern/efi/sb: Enforce verification of font files
As a mitigation and hardening measure enforce verification of font
files. Then only trusted font files can be load. This will reduce the
attack surface at cost of losing the ability of end-users to customize
fonts if e.g. UEFI Secure Boot is enabled. Vendors can always customize
fonts because they have ability to pack fonts into their GRUB bundles.
This goal is achieved by:
* Removing GRUB_FILE_TYPE_FONT from shim lock verifier's
skip-verification list.
* Adding GRUB_FILE_TYPE_FONT to lockdown verifier's defer-auth list,
so font files must be verified by a verifier before they can be loaded.
Suggested-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Zhang Boyang <zhangboyang.id@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/kern/efi/sb.c | 1 -
grub-core/kern/lockdown.c | 1 +
2 files changed, 1 insertion(+), 1 deletion(-)
diff --git a/grub-core/kern/efi/sb.c b/grub-core/kern/efi/sb.c
index 89c4bb3fd..db42c2539 100644
--- a/grub-core/kern/efi/sb.c
+++ b/grub-core/kern/efi/sb.c
@@ -145,7 +145,6 @@ shim_lock_verifier_init (grub_file_t io __attribute__ ((unused)),
case GRUB_FILE_TYPE_PRINT_BLOCKLIST:
case GRUB_FILE_TYPE_TESTLOAD:
case GRUB_FILE_TYPE_GET_SIZE:
- case GRUB_FILE_TYPE_FONT:
case GRUB_FILE_TYPE_ZFS_ENCRYPTION_KEY:
case GRUB_FILE_TYPE_CAT:
case GRUB_FILE_TYPE_HEXCAT:
diff --git a/grub-core/kern/lockdown.c b/grub-core/kern/lockdown.c
index 0bc70fd42..af6d493cd 100644
--- a/grub-core/kern/lockdown.c
+++ b/grub-core/kern/lockdown.c
@@ -51,6 +51,7 @@ lockdown_verifier_init (grub_file_t io __attribute__ ((unused)),
case GRUB_FILE_TYPE_EFI_CHAINLOADED_IMAGE:
case GRUB_FILE_TYPE_ACPI_TABLE:
case GRUB_FILE_TYPE_DEVICE_TREE_IMAGE:
+ case GRUB_FILE_TYPE_FONT:
*flags = GRUB_VERIFY_FLAGS_DEFER_AUTH;
/* Fall through. */
--
2.30.2