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From 73f214761cff76a18a2a867976bdd3a9adb00b67 Mon Sep 17 00:00:00 2001
From: Javier Martinez Canillas <javierm@redhat.com>
Date: Wed, 24 Feb 2021 14:44:38 +0100
Subject: [PATCH] loader/xnu: Don't allow loading extension and packages when
locked down
The shim_lock verifier validates the XNU kernels but no its extensions
and packages. Prevent these to be loaded when the GRUB is locked down.
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Upstream-Status: Backport [https://git.savannah.gnu.org/cgit/grub.git/commit/?id=9c5565135f12400a925ee901b25984e7af4442f5]
CVE: CVE-2020-27779
Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com>
---
grub-core/loader/xnu.c | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)
diff --git a/grub-core/loader/xnu.c b/grub-core/loader/xnu.c
index 77d7060..07232d2 100644
--- a/grub-core/loader/xnu.c
+++ b/grub-core/loader/xnu.c
@@ -1482,20 +1482,23 @@ GRUB_MOD_INIT(xnu)
N_("Load XNU image."));
cmd_kernel64 = grub_register_command ("xnu_kernel64", grub_cmd_xnu_kernel64,
0, N_("Load 64-bit XNU image."));
- cmd_mkext = grub_register_command ("xnu_mkext", grub_cmd_xnu_mkext, 0,
- N_("Load XNU extension package."));
- cmd_kext = grub_register_command ("xnu_kext", grub_cmd_xnu_kext, 0,
- N_("Load XNU extension."));
- cmd_kextdir = grub_register_command ("xnu_kextdir", grub_cmd_xnu_kextdir,
- /* TRANSLATORS: OSBundleRequired is a
- variable name in xnu extensions
- manifests. It behaves mostly like
- GNU/Linux runlevels.
- */
- N_("DIRECTORY [OSBundleRequired]"),
- /* TRANSLATORS: There are many extensions
- in extension directory. */
- N_("Load XNU extension directory."));
+ cmd_mkext = grub_register_command_lockdown ("xnu_mkext", grub_cmd_xnu_mkext, 0,
+ N_("Load XNU extension package."));
+ cmd_kext = grub_register_command_lockdown ("xnu_kext", grub_cmd_xnu_kext, 0,
+ N_("Load XNU extension."));
+ cmd_kextdir = grub_register_command_lockdown ("xnu_kextdir", grub_cmd_xnu_kextdir,
+ /*
+ * TRANSLATORS: OSBundleRequired is
+ * a variable name in xnu extensions
+ * manifests. It behaves mostly like
+ * GNU/Linux runlevels.
+ */
+ N_("DIRECTORY [OSBundleRequired]"),
+ /*
+ * TRANSLATORS: There are many extensions
+ * in extension directory.
+ */
+ N_("Load XNU extension directory."));
cmd_ramdisk = grub_register_command ("xnu_ramdisk", grub_cmd_xnu_ramdisk, 0,
/* TRANSLATORS: ramdisk here isn't identifier. It can be translated. */
N_("Load XNU ramdisk. "
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