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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: David Howells <dhowells@redhat.com>
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Date: Tue, 27 Feb 2018 10:04:55 +0000
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Subject: [PATCH] efi: Add an EFI_SECURE_BOOT flag to indicate secure boot mode
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UEFI machines can be booted in Secure Boot mode.  Add an EFI_SECURE_BOOT
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flag that can be passed to efi_enabled() to find out whether secure boot is
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enabled.
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Move the switch-statement in x86's setup_arch() that inteprets the
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secure_boot boot parameter to generic code and set the bit there.
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Upstream Status: RHEL only
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Suggested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
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Signed-off-by: David Howells <dhowells@redhat.com>
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Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
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cc: linux-efi@vger.kernel.org
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[Rebased for context; efi_is_table_address was moved to arch/x86]
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Signed-off-by: Jeremy Cline <jcline@redhat.com>
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---
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 arch/x86/kernel/setup.c           | 14 +-----------
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 drivers/firmware/efi/Makefile     |  1 +
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 drivers/firmware/efi/secureboot.c | 38 +++++++++++++++++++++++++++++++
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 include/linux/efi.h               | 18 ++++++++++-----
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 4 files changed, 52 insertions(+), 19 deletions(-)
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 create mode 100644 drivers/firmware/efi/secureboot.c
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diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
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index 112efbef3414..c9de4b36ca51 100644
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--- a/arch/x86/kernel/setup.c
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+++ b/arch/x86/kernel/setup.c
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@@ -1255,19 +1255,7 @@ void __init setup_arch(char **cmdline_p)
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 	/* Allocate bigger log buffer */
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 	setup_log_buf(1);
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-	if (efi_enabled(EFI_BOOT)) {
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-		switch (boot_params.secure_boot) {
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-		case efi_secureboot_mode_disabled:
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-			pr_info("Secure boot disabled\n");
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-			break;
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-		case efi_secureboot_mode_enabled:
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-			pr_info("Secure boot enabled\n");
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-			break;
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-		default:
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-			pr_info("Secure boot could not be determined\n");
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-			break;
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-		}
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-	}
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+	efi_set_secure_boot(boot_params.secure_boot);
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 	reserve_initrd();
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diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
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index 7a216984552b..f0ef02d733af 100644
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--- a/drivers/firmware/efi/Makefile
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+++ b/drivers/firmware/efi/Makefile
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@@ -25,6 +25,7 @@ obj-$(CONFIG_EFI_FAKE_MEMMAP)		+= fake_map.o
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 obj-$(CONFIG_EFI_BOOTLOADER_CONTROL)	+= efibc.o
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 obj-$(CONFIG_EFI_TEST)			+= test/
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 obj-$(CONFIG_EFI_DEV_PATH_PARSER)	+= dev-path-parser.o
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+obj-$(CONFIG_EFI)			+= secureboot.o
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 obj-$(CONFIG_APPLE_PROPERTIES)		+= apple-properties.o
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 obj-$(CONFIG_EFI_RCI2_TABLE)		+= rci2-table.o
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 obj-$(CONFIG_EFI_EMBEDDED_FIRMWARE)	+= embedded-firmware.o
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diff --git a/drivers/firmware/efi/secureboot.c b/drivers/firmware/efi/secureboot.c
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new file mode 100644
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index 000000000000..de0a3714a5d4
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--- /dev/null
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+++ b/drivers/firmware/efi/secureboot.c
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@@ -0,0 +1,38 @@
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+/* Core kernel secure boot support.
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+ *
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+ * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
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+ * Written by David Howells (dhowells@redhat.com)
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+ *
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+ * This program is free software; you can redistribute it and/or
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+ * modify it under the terms of the GNU General Public Licence
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+ * as published by the Free Software Foundation; either version
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+ * 2 of the Licence, or (at your option) any later version.
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+ */
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+
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+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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+
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+#include <linux/efi.h>
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+#include <linux/kernel.h>
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+#include <linux/printk.h>
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+
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+/*
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+ * Decide what to do when UEFI secure boot mode is enabled.
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+ */
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+void __init efi_set_secure_boot(enum efi_secureboot_mode mode)
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+{
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+	if (efi_enabled(EFI_BOOT)) {
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+		switch (mode) {
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+		case efi_secureboot_mode_disabled:
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+			pr_info("Secure boot disabled\n");
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+			break;
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+		case efi_secureboot_mode_enabled:
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+			set_bit(EFI_SECURE_BOOT, &efi.flags);
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+			pr_info("Secure boot enabled\n");
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+			break;
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+		default:
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+			pr_warn("Secure boot could not be determined (mode %u)\n",
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+				   mode);
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+			break;
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+		}
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+	}
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+}
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diff --git a/include/linux/efi.h b/include/linux/efi.h
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index 92aa4697f558..1cdc5d8b6ac3 100644
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--- a/include/linux/efi.h
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+++ b/include/linux/efi.h
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@@ -785,6 +785,14 @@ extern int __init efi_setup_pcdp_console(char *);
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 #define EFI_MEM_ATTR		10	/* Did firmware publish an EFI_MEMORY_ATTRIBUTES table? */
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 #define EFI_MEM_NO_SOFT_RESERVE	11	/* Is the kernel configured to ignore soft reservations? */
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 #define EFI_PRESERVE_BS_REGIONS	12	/* Are EFI boot-services memory segments available? */
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+#define EFI_SECURE_BOOT		13	/* Are we in Secure Boot mode? */
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+
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+enum efi_secureboot_mode {
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+	efi_secureboot_mode_unset,
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+	efi_secureboot_mode_unknown,
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+	efi_secureboot_mode_disabled,
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+	efi_secureboot_mode_enabled,
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+};
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 #ifdef CONFIG_EFI
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 /*
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@@ -796,6 +804,8 @@ static inline bool efi_enabled(int feature)
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 }
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 extern void efi_reboot(enum reboot_mode reboot_mode, const char *__unused);
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+extern void __init efi_set_secure_boot(enum efi_secureboot_mode mode);
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+
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 bool __pure __efi_soft_reserve_enabled(void);
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 static inline bool __pure efi_soft_reserve_enabled(void)
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@@ -822,6 +832,8 @@ efi_capsule_pending(int *reset_type)
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 	return false;
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 }
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+static inline void efi_set_secure_boot(enum efi_secureboot_mode mode) {}
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+
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 static inline bool efi_soft_reserve_enabled(void)
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 {
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 	return false;
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@@ -1094,12 +1106,6 @@ static inline bool efi_runtime_disabled(void) { return true; }
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 extern void efi_call_virt_check_flags(unsigned long flags, const char *call);
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 extern unsigned long efi_call_virt_save_flags(void);
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-enum efi_secureboot_mode {
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-	efi_secureboot_mode_unset,
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-	efi_secureboot_mode_unknown,
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-	efi_secureboot_mode_disabled,
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-	efi_secureboot_mode_enabled,
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-};
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 enum efi_secureboot_mode efi_get_secureboot(void);
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 #ifdef CONFIG_RESET_ATTACK_MITIGATION
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-- 
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2.28.0
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