kumquat-buildroot/boot/grub2/0006-kern-efi-sb-Reject-non-kernel-files-in-the-shim_lock.patch
Thomas Petazzoni 65c99394ff boot/grub2: backport fixes for numerous CVEs
Grub 2.06 is affected by a number of CVEs, which have been fixed in
the master branch of Grub, but are not yet part of any release (there
is a 2.12-rc1 release, but nothing else between 2.06 and 2.12-rc1).

So this patch backports the relevant fixes for CVE-2022-28736,
CVE-2022-28735, CVE-2021-3695, CVE-2021-3696, CVE-2021-3697,
CVE-2022-28733, CVE-2022-28734, CVE-2022-2601 and CVE-2022-3775.

It should be noted that CVE-2021-3695, CVE-2021-3696, CVE-2021-3697
are not reported as affecting Grub by our CVE matching logic because
the NVD database uses an incorrect CPE ID in those CVEs: it uses
"grub" as the product instead of "grub2" like all other CVEs for
grub. This issue has been reported to the NVD maintainers.

This requires backporting a lot of patches, but jumping from 2.06 to
2.12-rc1 implies getting 592 commits, which is quite a lot.

All Grub test cases are working fine:

  https://gitlab.com/tpetazzoni/buildroot/-/pipelines/984500585
  https://gitlab.com/tpetazzoni/buildroot/-/pipelines/984500679

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[Arnout: fix check-package warning in patch 0002]
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>
2023-08-30 21:54:23 +02:00

106 lines
3.6 KiB
Diff

From 1e1b1271b7a7c6ac20a4c5f8e0dc29614b4975d1 Mon Sep 17 00:00:00 2001
From: Julian Andres Klode <julian.klode@canonical.com>
Date: Thu, 2 Dec 2021 15:03:53 +0100
Subject: [PATCH] kern/efi/sb: Reject non-kernel files in the shim_lock
verifier
We must not allow other verifiers to pass things like the GRUB modules.
Instead of maintaining a blocklist, maintain an allowlist of things
that we do not care about.
This allowlist really should be made reusable, and shared by the
lockdown verifier, but this is the minimal patch addressing
security concerns where the TPM verifier was able to mark modules
as verified (or the OpenPGP verifier for that matter), when it
should not do so on shim-powered secure boot systems.
Fixes: CVE-2022-28735
Signed-off-by: Julian Andres Klode <julian.klode@canonical.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Upstream: 6fe755c5c07bb386fda58306bfd19e4a1c974c53
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
---
grub-core/kern/efi/sb.c | 39 ++++++++++++++++++++++++++++++++++++---
include/grub/verify.h | 1 +
2 files changed, 37 insertions(+), 3 deletions(-)
diff --git a/grub-core/kern/efi/sb.c b/grub-core/kern/efi/sb.c
index c52ec6226..89c4bb3fd 100644
--- a/grub-core/kern/efi/sb.c
+++ b/grub-core/kern/efi/sb.c
@@ -119,10 +119,11 @@ shim_lock_verifier_init (grub_file_t io __attribute__ ((unused)),
void **context __attribute__ ((unused)),
enum grub_verify_flags *flags)
{
- *flags = GRUB_VERIFY_FLAGS_SKIP_VERIFICATION;
+ *flags = GRUB_VERIFY_FLAGS_NONE;
switch (type & GRUB_FILE_TYPE_MASK)
{
+ /* Files we check. */
case GRUB_FILE_TYPE_LINUX_KERNEL:
case GRUB_FILE_TYPE_MULTIBOOT_KERNEL:
case GRUB_FILE_TYPE_BSD_KERNEL:
@@ -130,11 +131,43 @@ shim_lock_verifier_init (grub_file_t io __attribute__ ((unused)),
case GRUB_FILE_TYPE_PLAN9_KERNEL:
case GRUB_FILE_TYPE_EFI_CHAINLOADED_IMAGE:
*flags = GRUB_VERIFY_FLAGS_SINGLE_CHUNK;
+ return GRUB_ERR_NONE;
- /* Fall through. */
+ /* Files that do not affect secureboot state. */
+ case GRUB_FILE_TYPE_NONE:
+ case GRUB_FILE_TYPE_LOOPBACK:
+ case GRUB_FILE_TYPE_LINUX_INITRD:
+ case GRUB_FILE_TYPE_OPENBSD_RAMDISK:
+ case GRUB_FILE_TYPE_XNU_RAMDISK:
+ case GRUB_FILE_TYPE_SIGNATURE:
+ case GRUB_FILE_TYPE_PUBLIC_KEY:
+ case GRUB_FILE_TYPE_PUBLIC_KEY_TRUST:
+ 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:
+ case GRUB_FILE_TYPE_CMP:
+ case GRUB_FILE_TYPE_HASHLIST:
+ case GRUB_FILE_TYPE_TO_HASH:
+ case GRUB_FILE_TYPE_KEYBOARD_LAYOUT:
+ case GRUB_FILE_TYPE_PIXMAP:
+ case GRUB_FILE_TYPE_GRUB_MODULE_LIST:
+ case GRUB_FILE_TYPE_CONFIG:
+ case GRUB_FILE_TYPE_THEME:
+ case GRUB_FILE_TYPE_GETTEXT_CATALOG:
+ case GRUB_FILE_TYPE_FS_SEARCH:
+ case GRUB_FILE_TYPE_LOADENV:
+ case GRUB_FILE_TYPE_SAVEENV:
+ case GRUB_FILE_TYPE_VERIFY_SIGNATURE:
+ *flags = GRUB_VERIFY_FLAGS_SKIP_VERIFICATION;
+ return GRUB_ERR_NONE;
+ /* Other files. */
default:
- return GRUB_ERR_NONE;
+ return grub_error (GRUB_ERR_ACCESS_DENIED, N_("prohibited by secure boot policy"));
}
}
diff --git a/include/grub/verify.h b/include/grub/verify.h
index cd129c398..672ae1692 100644
--- a/include/grub/verify.h
+++ b/include/grub/verify.h
@@ -24,6 +24,7 @@
enum grub_verify_flags
{
+ GRUB_VERIFY_FLAGS_NONE = 0,
GRUB_VERIFY_FLAGS_SKIP_VERIFICATION = 1,
GRUB_VERIFY_FLAGS_SINGLE_CHUNK = 2,
/* Defer verification to another authority. */
--
2.41.0