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[PATCH 1/4] efi: Load env block from GRUB_ENV EFI variable in early init
From: |
Glenn Washburn |
Subject: |
[PATCH 1/4] efi: Load env block from GRUB_ENV EFI variable in early init |
Date: |
Wed, 26 Jul 2023 15:59:59 -0500 |
From: Peter Jones <pjones@redhat.com>
This allows setting GRUB variables before any user interaction or GRUB
script can run. It is primarily intended to be used to turn on early
debugging.
Signed-off-by: Peter Jones <pjones@redhat.com>
Replace grub_efi_guid_t -> grub_guid_t
Signed-off-by: Glenn Washburn <development@efficientek.com>
---
grub-core/Makefile.core.def | 1 +
grub-core/kern/efi/init.c | 31 +++++++++++++++++++++++++++++++
include/grub/efi/efi.h | 5 +++++
3 files changed, 37 insertions(+)
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index d2cf29584a1a..0b447dd6dc67 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -219,6 +219,7 @@ kernel = {
efi = kern/efi/acpi.c;
efi = kern/efi/sb.c;
efi = kern/lockdown.c;
+ efi = lib/envblk.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/init.c b/grub-core/kern/efi/init.c
index 9cdda3f5ca05..18329b1eacd7 100644
--- a/grub-core/kern/efi/init.c
+++ b/grub-core/kern/efi/init.c
@@ -28,8 +28,11 @@
#include <grub/env.h>
#include <grub/mm.h>
#include <grub/kernel.h>
+
#include <grub/stack_protector.h>
+#include <grub/lib/envblk.h>
+
#ifdef GRUB_STACK_PROTECTOR
static grub_efi_char16_t stack_chk_fail_msg[] =
@@ -111,6 +114,31 @@ stack_protector_init (void)
grub_addr_t grub_modbase;
+/* Helper for grub_efi_env_init */
+static int
+set_var (const char *name, const char *value,
+ void *whitelist __attribute__((__unused__)))
+{
+ grub_env_set (name, value);
+ return 0;
+}
+
+static void
+grub_efi_env_init (void)
+{
+ grub_guid_t efi_grub_guid = GRUB_EFI_GRUB_VARIABLE_GUID;
+ struct grub_envblk envblk_s = { NULL, 0 };
+ grub_envblk_t envblk = &envblk_s;
+
+ grub_efi_get_variable ("GRUB_ENV", &efi_grub_guid, &envblk_s.size,
+ (void **) &envblk_s.buf);
+ if (envblk_s.buf == NULL || envblk_s.size < 1)
+ return;
+
+ grub_envblk_iterate (envblk, NULL, set_var);
+ grub_free (envblk_s.buf);
+}
+
void
grub_efi_init (void)
{
@@ -124,6 +152,9 @@ grub_efi_init (void)
/* Initialize the memory management system. */
grub_efi_mm_init ();
+ /* Populate environment with variables from EFI envblk, if it exists. */
+ grub_efi_env_init ();
+
/*
* Lockdown the GRUB and register the shim_lock verifier
* if the UEFI Secure Boot is enabled.
diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
index 564c2f62045b..aa6a360a4999 100644
--- a/include/grub/efi/efi.h
+++ b/include/grub/efi/efi.h
@@ -25,6 +25,11 @@
#include <grub/efi/api.h>
#include <grub/efi/pe32.h>
+#define GRUB_EFI_GRUB_VARIABLE_GUID \
+ { 0x91376aff, 0xcba6, 0x42be, \
+ { 0x94, 0x9d, 0x06, 0xfd, 0xe8, 0x11, 0x28, 0xe8 } \
+ }
+
#define GRUB_LINUX_ARM_MAGIC_SIGNATURE 0x016f2818
struct linux_arch_kernel_header {
--
2.34.1