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grub2/0005-efi-Add-secure-boot-detection.patch

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From 12650d0953372674fb587c2e6331257fc7a90a94 Mon Sep 17 00:00:00 2001
From: Daniel Kiper <daniel.kiper@oracle.com>
Date: Thu, 3 Dec 2020 16:01:48 +0100
Subject: [PATCH 05/46] efi: Add secure boot detection
Introduce grub_efi_get_secureboot() function which returns whether
UEFI Secure Boot is enabled or not on UEFI systems.
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Marco A Benatto <mbenatto@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---
grub-core/Makefile.am | 1 +
grub-core/Makefile.core.def | 1 +
grub-core/kern/efi/sb.c | 109 ++++++++++++++++++++++++++++++++++++
include/grub/efi/sb.h | 40 +++++++++++++
4 files changed, 151 insertions(+)
create mode 100644 grub-core/kern/efi/sb.c
create mode 100644 include/grub/efi/sb.h
diff --git a/grub-core/Makefile.am b/grub-core/Makefile.am
index ede596170..5ff3afd62 100644
--- a/grub-core/Makefile.am
+++ b/grub-core/Makefile.am
@@ -71,6 +71,7 @@ KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/command.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/device.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/disk.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/dl.h
+KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/efi/sb.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/env.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/env_private.h
KERNEL_HEADER_FILES += $(top_srcdir)/include/grub/err.h
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index ce4f71ebe..072b1628c 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -203,6 +203,7 @@ kernel = {
efi = term/efi/console.c;
efi = kern/acpi.c;
efi = kern/efi/acpi.c;
+ efi = kern/efi/sb.c;
i386_coreboot = kern/i386/pc/acpi.c;
i386_multiboot = kern/i386/pc/acpi.c;
i386_coreboot = kern/acpi.c;
diff --git a/grub-core/kern/efi/sb.c b/grub-core/kern/efi/sb.c
new file mode 100644
index 000000000..19658d962
--- /dev/null
+++ b/grub-core/kern/efi/sb.c
@@ -0,0 +1,109 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2020 Free Software Foundation, Inc.
+ *
+ * GRUB is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * UEFI Secure Boot related checkings.
+ */
+
+#include <grub/efi/efi.h>
+#include <grub/efi/pe32.h>
+#include <grub/efi/sb.h>
+#include <grub/err.h>
+#include <grub/i386/linux.h>
+#include <grub/mm.h>
+#include <grub/types.h>
+
+/*
+ * Determine whether we're in secure boot mode.
+ *
+ * Please keep the logic in sync with the Linux kernel,
+ * drivers/firmware/efi/libstub/secureboot.c:efi_get_secureboot().
+ */
+grub_uint8_t
+grub_efi_get_secureboot (void)
+{
+ static grub_efi_guid_t efi_variable_guid = GRUB_EFI_GLOBAL_VARIABLE_GUID;
+ static grub_efi_guid_t efi_shim_lock_guid = GRUB_EFI_SHIM_LOCK_GUID;
+ grub_efi_status_t status;
+ grub_efi_uint32_t attr = 0;
+ grub_size_t size = 0;
+ grub_uint8_t *secboot = NULL;
+ grub_uint8_t *setupmode = NULL;
+ grub_uint8_t *moksbstate = NULL;
+ grub_uint8_t secureboot = GRUB_EFI_SECUREBOOT_MODE_UNKNOWN;
+ const char *secureboot_str = "UNKNOWN";
+
+ status = grub_efi_get_variable ("SecureBoot", &efi_variable_guid,
+ &size, (void **) &secboot);
+
+ if (status == GRUB_EFI_NOT_FOUND)
+ {
+ secureboot = GRUB_EFI_SECUREBOOT_MODE_DISABLED;
+ goto out;
+ }
+
+ if (status != GRUB_EFI_SUCCESS)
+ goto out;
+
+ status = grub_efi_get_variable ("SetupMode", &efi_variable_guid,
+ &size, (void **) &setupmode);
+
+ if (status != GRUB_EFI_SUCCESS)
+ goto out;
+
+ if ((*secboot == 0) || (*setupmode == 1))
+ {
+ secureboot = GRUB_EFI_SECUREBOOT_MODE_DISABLED;
+ goto out;
+ }
+
+ /*
+ * See if a user has put the shim into insecure mode. If so, and if the
+ * variable doesn't have the runtime attribute set, we might as well
+ * honor that.
+ */
+ status = grub_efi_get_variable_with_attributes ("MokSBState", &efi_shim_lock_guid,
+ &size, (void **) &moksbstate, &attr);
+
+ /* If it fails, we don't care why. Default to secure. */
+ if (status != GRUB_EFI_SUCCESS)
+ {
+ secureboot = GRUB_EFI_SECUREBOOT_MODE_ENABLED;
+ goto out;
+ }
+
+ if (!(attr & GRUB_EFI_VARIABLE_RUNTIME_ACCESS) && *moksbstate == 1)
+ {
+ secureboot = GRUB_EFI_SECUREBOOT_MODE_DISABLED;
+ goto out;
+ }
+
+ secureboot = GRUB_EFI_SECUREBOOT_MODE_ENABLED;
+
+ out:
+ grub_free (moksbstate);
+ grub_free (setupmode);
+ grub_free (secboot);
+
+ if (secureboot == GRUB_EFI_SECUREBOOT_MODE_DISABLED)
+ secureboot_str = "Disabled";
+ else if (secureboot == GRUB_EFI_SECUREBOOT_MODE_ENABLED)
+ secureboot_str = "Enabled";
+
+ grub_dprintf ("efi", "UEFI Secure Boot state: %s\n", secureboot_str);
+
+ return secureboot;
+}
diff --git a/include/grub/efi/sb.h b/include/grub/efi/sb.h
new file mode 100644
index 000000000..a33d985e3
--- /dev/null
+++ b/include/grub/efi/sb.h
@@ -0,0 +1,40 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2020 Free Software Foundation, Inc.
+ *
+ * GRUB is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GRUB_EFI_SB_H
+#define GRUB_EFI_SB_H 1
+
+#include <grub/types.h>
+#include <grub/dl.h>
+
+#define GRUB_EFI_SECUREBOOT_MODE_UNSET 0
+#define GRUB_EFI_SECUREBOOT_MODE_UNKNOWN 1
+#define GRUB_EFI_SECUREBOOT_MODE_DISABLED 2
+#define GRUB_EFI_SECUREBOOT_MODE_ENABLED 3
+
+#ifdef GRUB_MACHINE_EFI
+extern grub_uint8_t
+EXPORT_FUNC (grub_efi_get_secureboot) (void);
+#else
+static inline grub_uint8_t
+grub_efi_get_secureboot (void)
+{
+ return GRUB_EFI_SECUREBOOT_MODE_UNSET;
+}
+#endif
+#endif /* GRUB_EFI_SB_H */
--
2.26.2
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