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[GIT PULL 0/7] EFI updates for v4.11 part 2

Started byArd Biesheuvel <ard.biesheuvel@linaro.org>
First post2017-02-06 12:30 +0100
Last post2017-02-07 10:50 +0100
Articles 5 — 2 participants

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Contents

  [GIT PULL 0/7] EFI updates for v4.11 part 2 Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-02-06 12:30 +0100
    [PATCH 4/7] efi: Get the secure boot status Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-02-06 12:30 +0100
      [tip:efi/core] efi: Get and store the secure boot status tip-bot for David Howells <tipbot@zytor.com> - 2017-02-07 10:50 +0100
    [PATCH 1/7] x86/efi: Allow invocation of arbitrary runtime services Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-02-06 12:30 +0100
      [tip:efi/core] x86/efi: Allow invocation of arbitrary runtime  services tip-bot for David Howells <tipbot@zytor.com> - 2017-02-07 10:50 +0100

#1574568 — [GIT PULL 0/7] EFI updates for v4.11 part 2

FromArd Biesheuvel <ard.biesheuvel@linaro.org>
Date2017-02-06 12:30 +0100
Subject[GIT PULL 0/7] EFI updates for v4.11 part 2
Message-ID<t7PEC-4iF-5@gated-at.bofh.it>
These are patches that were still being discussed when I sent the first pull
request last week, but we feel they are now in shape to be merged.

Please pull.

The following changes since commit a21a300289bb5a582cc96be23446fa35236a6a9a:

  efi: libstub: Preserve .debug sections after absolute relocation check (2017-01-31 11:47:39 +0000)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git tags/efi-next

for you to fetch changes up to dfe7b0e7e1ab9dc02d754c7dd11e465be0944603:

  efi: libstub: Make file I/O chunking x86-specific (2017-02-03 17:01:06 +0000)

----------------------------------------------------------------
Some more EFI changes we've queued up for v4.11:
* Changes to the EFI init code to infer from various EFI and shim variables
  whether secure boot authentication was performed at boot time. (Note that
  this is the uncontroversial part: I expect some fierce debate about future
  patches that impose or relax certain restrictions based on this information,
  but collecting it is useful in itself.)
* Disable a x86 specific file I/O chunking workaround on ARM so it does not
  spuriously trigger build time checks in the ARM decompressor.

----------------------------------------------------------------
Ard Biesheuvel (1):
      efi: libstub: Make file I/O chunking x86-specific

David Howells (5):
      x86/efi: Allow invocation of arbitrary runtime services
      arm/efi: Allow invocation of arbitrary runtime services
      efi: Add SHIM and image security database GUID definitions
      efi: Get the secure boot status
      efi: Print the secure boot status in x86 setup_arch()

Josh Boyer (1):
      efi: Disable secure boot if shim is in insecure mode

 Documentation/x86/zero-page.txt                |  2 +
 arch/arm/include/asm/efi.h                     |  1 +
 arch/arm64/include/asm/efi.h                   |  1 +
 arch/x86/boot/compressed/eboot.c               |  8 +++
 arch/x86/boot/compressed/head_32.S             |  6 +-
 arch/x86/boot/compressed/head_64.S             |  8 +--
 arch/x86/include/asm/efi.h                     |  5 ++
 arch/x86/include/uapi/asm/bootparam.h          |  3 +-
 arch/x86/kernel/asm-offsets.c                  |  1 +
 arch/x86/kernel/setup.c                        | 14 +++++
 drivers/firmware/efi/libstub/Makefile          |  2 +-
 drivers/firmware/efi/libstub/arm-stub.c        | 63 ++-----------------
 drivers/firmware/efi/libstub/efi-stub-helper.c | 12 +++-
 drivers/firmware/efi/libstub/secureboot.c      | 86 ++++++++++++++++++++++++++
 include/linux/efi.h                            | 11 ++++
 15 files changed, 156 insertions(+), 67 deletions(-)
 create mode 100644 drivers/firmware/efi/libstub/secureboot.c

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#1574570 — [PATCH 4/7] efi: Get the secure boot status

FromArd Biesheuvel <ard.biesheuvel@linaro.org>
Date2017-02-06 12:30 +0100
Subject[PATCH 4/7] efi: Get the secure boot status
Message-ID<t7PED-4iF-33@gated-at.bofh.it>
In reply to#1574568
From: David Howells <dhowells@redhat.com>

Get the firmware's secure-boot status in the kernel boot wrapper and stash
it somewhere that the main kernel image can find.

The efi_get_secureboot() function is extracted from the arm stub and (a)
generalised so that it can be called from x86 and (b) made to use
efi_call_runtime() so that it can be run in mixed-mode.

For x86, it is stored in boot_params and can be overridden by the boot
loader or kexec.  This allows secure-boot mode to be passed on to a new
kernel.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 Documentation/x86/zero-page.txt           |  2 +
 arch/x86/boot/compressed/eboot.c          |  7 ++++
 arch/x86/include/uapi/asm/bootparam.h     |  3 +-
 arch/x86/kernel/asm-offsets.c             |  1 +
 drivers/firmware/efi/libstub/Makefile     |  2 +-
 drivers/firmware/efi/libstub/arm-stub.c   | 63 +++----------------------------
 drivers/firmware/efi/libstub/secureboot.c | 63 +++++++++++++++++++++++++++++++
 include/linux/efi.h                       |  8 ++++
 8 files changed, 90 insertions(+), 59 deletions(-)
 create mode 100644 drivers/firmware/efi/libstub/secureboot.c

diff --git a/Documentation/x86/zero-page.txt b/Documentation/x86/zero-page.txt
index 95a4d34af3fd..b8527c6b7646 100644
--- a/Documentation/x86/zero-page.txt
+++ b/Documentation/x86/zero-page.txt
@@ -31,6 +31,8 @@ Offset	Proto	Name		Meaning
 1E9/001	ALL	eddbuf_entries	Number of entries in eddbuf (below)
 1EA/001	ALL	edd_mbr_sig_buf_entries	Number of entries in edd_mbr_sig_buffer
 				(below)
+1EB/001	ALL     kbd_status      Numlock is enabled
+1EC/001	ALL     secure_boot	Secure boot is enabled in the firmware
 1EF/001	ALL	sentinel	Used to detect broken bootloaders
 290/040	ALL	edd_mbr_sig_buffer EDD MBR signatures
 2D0/A00	ALL	e820_map	E820 memory map table
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index f99978db6b6f..801c7a158e55 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -988,6 +988,13 @@ struct boot_params *efi_main(struct efi_config *c,
 	else
 		setup_boot_services32(efi_early);
 
+	/*
+	 * If the boot loader gave us a value for secure_boot then we use that,
+	 * otherwise we ask the BIOS.
+	 */
+	if (boot_params->secure_boot == efi_secureboot_mode_unset)
+		boot_params->secure_boot = efi_get_secureboot(sys_table);
+
 	setup_graphics(boot_params);
 
 	setup_efi_pci(boot_params);
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index b10bf319ed20..5138dacf8bb8 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -135,7 +135,8 @@ struct boot_params {
 	__u8  eddbuf_entries;				/* 0x1e9 */
 	__u8  edd_mbr_sig_buf_entries;			/* 0x1ea */
 	__u8  kbd_status;				/* 0x1eb */
-	__u8  _pad5[3];					/* 0x1ec */
+	__u8  secure_boot;				/* 0x1ec */
+	__u8  _pad5[2];					/* 0x1ed */
 	/*
 	 * The sentinel is set to a nonzero value (0xff) in header.S.
 	 *
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index c62e015b126c..de827d6ac8c2 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -81,6 +81,7 @@ void common(void) {
 
 	BLANK();
 	OFFSET(BP_scratch, boot_params, scratch);
+	OFFSET(BP_secure_boot, boot_params, secure_boot);
 	OFFSET(BP_loadflags, boot_params, hdr.loadflags);
 	OFFSET(BP_hardware_subarch, boot_params, hdr.hardware_subarch);
 	OFFSET(BP_version, boot_params, hdr.version);
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 33e0e2f1a730..f7425960f6a5 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -28,7 +28,7 @@ OBJECT_FILES_NON_STANDARD	:= y
 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
 KCOV_INSTRUMENT			:= n
 
-lib-y				:= efi-stub-helper.o gop.o
+lib-y				:= efi-stub-helper.o gop.o secureboot.o
 
 # include the stub's generic dependencies from lib/ when building for ARM/arm64
 arm-deps := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c sort.c
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
index 6fca48c9e054..d4056c6be1ec 100644
--- a/drivers/firmware/efi/libstub/arm-stub.c
+++ b/drivers/firmware/efi/libstub/arm-stub.c
@@ -20,52 +20,6 @@
 
 bool __nokaslr;
 
-static int efi_get_secureboot(efi_system_table_t *sys_table_arg)
-{
-	static efi_char16_t const sb_var_name[] = {
-		'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
-	static efi_char16_t const sm_var_name[] = {
-		'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 };
-
-	efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
-	efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
-	u8 val;
-	unsigned long size = sizeof(val);
-	efi_status_t status;
-
-	status = f_getvar((efi_char16_t *)sb_var_name, (efi_guid_t *)&var_guid,
-			  NULL, &size, &val);
-
-	if (status != EFI_SUCCESS)
-		goto out_efi_err;
-
-	if (val == 0)
-		return 0;
-
-	status = f_getvar((efi_char16_t *)sm_var_name, (efi_guid_t *)&var_guid,
-			  NULL, &size, &val);
-
-	if (status != EFI_SUCCESS)
-		goto out_efi_err;
-
-	if (val == 1)
-		return 0;
-
-	return 1;
-
-out_efi_err:
-	switch (status) {
-	case EFI_NOT_FOUND:
-		return 0;
-	case EFI_DEVICE_ERROR:
-		return -EIO;
-	case EFI_SECURITY_VIOLATION:
-		return -EACCES;
-	default:
-		return -EINVAL;
-	}
-}
-
 efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
 			     void *__image, void **__fh)
 {
@@ -157,7 +111,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
 	efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
 	unsigned long reserve_addr = 0;
 	unsigned long reserve_size = 0;
-	int secure_boot = 0;
+	enum efi_secureboot_mode secure_boot;
 	struct screen_info *si;
 
 	/* Check if we were booted by the EFI firmware */
@@ -227,19 +181,14 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
 		pr_efi_err(sys_table, "Failed to parse EFI cmdline options\n");
 
 	secure_boot = efi_get_secureboot(sys_table);
-	if (secure_boot > 0)
-		pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
-
-	if (secure_boot < 0) {
-		pr_efi_err(sys_table,
-			"could not determine UEFI Secure Boot status.\n");
-	}
 
 	/*
-	 * Unauthenticated device tree data is a security hazard, so
-	 * ignore 'dtb=' unless UEFI Secure Boot is disabled.
+	 * Unauthenticated device tree data is a security hazard, so ignore
+	 * 'dtb=' unless UEFI Secure Boot is disabled.  We assume that secure
+	 * boot is enabled if we can't determine its state.
 	 */
-	if (secure_boot != 0 && strstr(cmdline_ptr, "dtb=")) {
+	if (secure_boot != efi_secureboot_mode_disabled &&
+	    strstr(cmdline_ptr, "dtb=")) {
 		pr_efi(sys_table, "Ignoring DTB from command line.\n");
 	} else {
 		status = handle_cmdline_files(sys_table, image, cmdline_ptr,
diff --git a/drivers/firmware/efi/libstub/secureboot.c b/drivers/firmware/efi/libstub/secureboot.c
new file mode 100644
index 000000000000..62d6904da800
--- /dev/null
+++ b/drivers/firmware/efi/libstub/secureboot.c
@@ -0,0 +1,63 @@
+/*
+ * Secure boot handling.
+ *
+ * Copyright (C) 2013,2014 Linaro Limited
+ *     Roy Franz <roy.franz@linaro.org
+ * Copyright (C) 2013 Red Hat, Inc.
+ *     Mark Salter <msalter@redhat.com>
+ *
+ * This file is part of the Linux kernel, and is made available under the
+ * terms of the GNU General Public License version 2.
+ *
+ */
+
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+/* BIOS variables */
+static const efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
+static const efi_char16_t const efi_SecureBoot_name[] = {
+	'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0
+};
+static const efi_char16_t const efi_SetupMode_name[] = {
+	'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0
+};
+
+#define get_efi_var(name, vendor, ...) \
+	efi_call_runtime(get_variable, \
+			 (efi_char16_t *)(name), (efi_guid_t *)(vendor), \
+			 __VA_ARGS__);
+
+/*
+ * Determine whether we're in secure boot mode.
+ */
+enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg)
+{
+	u8 secboot, setupmode;
+	unsigned long size;
+	efi_status_t status;
+
+	size = sizeof(secboot);
+	status = get_efi_var(efi_SecureBoot_name, &efi_variable_guid,
+			     NULL, &size, &secboot);
+	if (status != EFI_SUCCESS)
+		goto out_efi_err;
+
+	size = sizeof(setupmode);
+	status = get_efi_var(efi_SetupMode_name, &efi_variable_guid,
+			     NULL, &size, &setupmode);
+	if (status != EFI_SUCCESS)
+		goto out_efi_err;
+
+	if (secboot == 0 || setupmode == 1)
+		return efi_secureboot_mode_disabled;
+
+	pr_efi(sys_table_arg, "UEFI Secure Boot is enabled.\n");
+	return efi_secureboot_mode_enabled;
+
+out_efi_err:
+	pr_efi_err(sys_table_arg, "Could not determine UEFI Secure Boot status.\n");
+	if (status == EFI_NOT_FOUND)
+		return efi_secureboot_mode_disabled;
+	return efi_secureboot_mode_unknown;
+}
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 52c87de3e50d..729ee6a2579b 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1480,6 +1480,14 @@ efi_status_t efi_setup_gop(efi_system_table_t *sys_table_arg,
 bool efi_runtime_disabled(void);
 extern void efi_call_virt_check_flags(unsigned long flags, const char *call);
 
+enum efi_secureboot_mode {
+	efi_secureboot_mode_unset,
+	efi_secureboot_mode_unknown,
+	efi_secureboot_mode_disabled,
+	efi_secureboot_mode_enabled,
+};
+enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table);
+
 /*
  * Arch code can implement the following three template macros, avoiding
  * reptition for the void/non-void return cases of {__,}efi_call_virt():
-- 
2.7.4

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#1575515 — [tip:efi/core] efi: Get and store the secure boot status

Fromtip-bot for David Howells <tipbot@zytor.com>
Date2017-02-07 10:50 +0100
Subject[tip:efi/core] efi: Get and store the secure boot status
Message-ID<t8azn-16x-1@gated-at.bofh.it>
In reply to#1574570
Commit-ID:  de8cb458625c164bb3f93c4e415e479afce8fa9d
Gitweb:     http://git.kernel.org/tip/de8cb458625c164bb3f93c4e415e479afce8fa9d
Author:     David Howells <dhowells@redhat.com>
AuthorDate: Mon, 6 Feb 2017 11:22:43 +0000
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 7 Feb 2017 10:42:10 +0100

efi: Get and store the secure boot status

Get the firmware's secure-boot status in the kernel boot wrapper and stash
it somewhere that the main kernel image can find.

The efi_get_secureboot() function is extracted from the ARM stub and (a)
generalised so that it can be called from x86 and (b) made to use
efi_call_runtime() so that it can be run in mixed-mode.

For x86, it is stored in boot_params and can be overridden by the boot
loader or kexec.  This allows secure-boot mode to be passed on to a new
kernel.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1486380166-31868-5-git-send-email-ard.biesheuvel@linaro.org
[ Small readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 Documentation/x86/zero-page.txt           |  2 +
 arch/x86/boot/compressed/eboot.c          |  7 ++++
 arch/x86/include/uapi/asm/bootparam.h     |  3 +-
 arch/x86/kernel/asm-offsets.c             |  1 +
 drivers/firmware/efi/libstub/Makefile     |  2 +-
 drivers/firmware/efi/libstub/arm-stub.c   | 63 +++----------------------------
 drivers/firmware/efi/libstub/secureboot.c | 61 ++++++++++++++++++++++++++++++
 include/linux/efi.h                       |  8 ++++
 8 files changed, 88 insertions(+), 59 deletions(-)

diff --git a/Documentation/x86/zero-page.txt b/Documentation/x86/zero-page.txt
index 95a4d34..b8527c6 100644
--- a/Documentation/x86/zero-page.txt
+++ b/Documentation/x86/zero-page.txt
@@ -31,6 +31,8 @@ Offset	Proto	Name		Meaning
 1E9/001	ALL	eddbuf_entries	Number of entries in eddbuf (below)
 1EA/001	ALL	edd_mbr_sig_buf_entries	Number of entries in edd_mbr_sig_buffer
 				(below)
+1EB/001	ALL     kbd_status      Numlock is enabled
+1EC/001	ALL     secure_boot	Secure boot is enabled in the firmware
 1EF/001	ALL	sentinel	Used to detect broken bootloaders
 290/040	ALL	edd_mbr_sig_buffer EDD MBR signatures
 2D0/A00	ALL	e820_map	E820 memory map table
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index f99978d..801c7a1 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -988,6 +988,13 @@ struct boot_params *efi_main(struct efi_config *c,
 	else
 		setup_boot_services32(efi_early);
 
+	/*
+	 * If the boot loader gave us a value for secure_boot then we use that,
+	 * otherwise we ask the BIOS.
+	 */
+	if (boot_params->secure_boot == efi_secureboot_mode_unset)
+		boot_params->secure_boot = efi_get_secureboot(sys_table);
+
 	setup_graphics(boot_params);
 
 	setup_efi_pci(boot_params);
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index b10bf31..5138dac 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -135,7 +135,8 @@ struct boot_params {
 	__u8  eddbuf_entries;				/* 0x1e9 */
 	__u8  edd_mbr_sig_buf_entries;			/* 0x1ea */
 	__u8  kbd_status;				/* 0x1eb */
-	__u8  _pad5[3];					/* 0x1ec */
+	__u8  secure_boot;				/* 0x1ec */
+	__u8  _pad5[2];					/* 0x1ed */
 	/*
 	 * The sentinel is set to a nonzero value (0xff) in header.S.
 	 *
diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c
index c62e015..de827d6 100644
--- a/arch/x86/kernel/asm-offsets.c
+++ b/arch/x86/kernel/asm-offsets.c
@@ -81,6 +81,7 @@ void common(void) {
 
 	BLANK();
 	OFFSET(BP_scratch, boot_params, scratch);
+	OFFSET(BP_secure_boot, boot_params, secure_boot);
 	OFFSET(BP_loadflags, boot_params, hdr.loadflags);
 	OFFSET(BP_hardware_subarch, boot_params, hdr.hardware_subarch);
 	OFFSET(BP_version, boot_params, hdr.version);
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 33e0e2f..f742596 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -28,7 +28,7 @@ OBJECT_FILES_NON_STANDARD	:= y
 # Prevents link failures: __sanitizer_cov_trace_pc() is not linked in.
 KCOV_INSTRUMENT			:= n
 
-lib-y				:= efi-stub-helper.o gop.o
+lib-y				:= efi-stub-helper.o gop.o secureboot.o
 
 # include the stub's generic dependencies from lib/ when building for ARM/arm64
 arm-deps := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c sort.c
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
index 6fca48c..d4056c6 100644
--- a/drivers/firmware/efi/libstub/arm-stub.c
+++ b/drivers/firmware/efi/libstub/arm-stub.c
@@ -20,52 +20,6 @@
 
 bool __nokaslr;
 
-static int efi_get_secureboot(efi_system_table_t *sys_table_arg)
-{
-	static efi_char16_t const sb_var_name[] = {
-		'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
-	static efi_char16_t const sm_var_name[] = {
-		'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 };
-
-	efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
-	efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
-	u8 val;
-	unsigned long size = sizeof(val);
-	efi_status_t status;
-
-	status = f_getvar((efi_char16_t *)sb_var_name, (efi_guid_t *)&var_guid,
-			  NULL, &size, &val);
-
-	if (status != EFI_SUCCESS)
-		goto out_efi_err;
-
-	if (val == 0)
-		return 0;
-
-	status = f_getvar((efi_char16_t *)sm_var_name, (efi_guid_t *)&var_guid,
-			  NULL, &size, &val);
-
-	if (status != EFI_SUCCESS)
-		goto out_efi_err;
-
-	if (val == 1)
-		return 0;
-
-	return 1;
-
-out_efi_err:
-	switch (status) {
-	case EFI_NOT_FOUND:
-		return 0;
-	case EFI_DEVICE_ERROR:
-		return -EIO;
-	case EFI_SECURITY_VIOLATION:
-		return -EACCES;
-	default:
-		return -EINVAL;
-	}
-}
-
 efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
 			     void *__image, void **__fh)
 {
@@ -157,7 +111,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
 	efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
 	unsigned long reserve_addr = 0;
 	unsigned long reserve_size = 0;
-	int secure_boot = 0;
+	enum efi_secureboot_mode secure_boot;
 	struct screen_info *si;
 
 	/* Check if we were booted by the EFI firmware */
@@ -227,19 +181,14 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
 		pr_efi_err(sys_table, "Failed to parse EFI cmdline options\n");
 
 	secure_boot = efi_get_secureboot(sys_table);
-	if (secure_boot > 0)
-		pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
-
-	if (secure_boot < 0) {
-		pr_efi_err(sys_table,
-			"could not determine UEFI Secure Boot status.\n");
-	}
 
 	/*
-	 * Unauthenticated device tree data is a security hazard, so
-	 * ignore 'dtb=' unless UEFI Secure Boot is disabled.
+	 * Unauthenticated device tree data is a security hazard, so ignore
+	 * 'dtb=' unless UEFI Secure Boot is disabled.  We assume that secure
+	 * boot is enabled if we can't determine its state.
 	 */
-	if (secure_boot != 0 && strstr(cmdline_ptr, "dtb=")) {
+	if (secure_boot != efi_secureboot_mode_disabled &&
+	    strstr(cmdline_ptr, "dtb=")) {
 		pr_efi(sys_table, "Ignoring DTB from command line.\n");
 	} else {
 		status = handle_cmdline_files(sys_table, image, cmdline_ptr,
diff --git a/drivers/firmware/efi/libstub/secureboot.c b/drivers/firmware/efi/libstub/secureboot.c
new file mode 100644
index 0000000..b20b8b4
--- /dev/null
+++ b/drivers/firmware/efi/libstub/secureboot.c
@@ -0,0 +1,61 @@
+/*
+ * Secure boot handling.
+ *
+ * Copyright (C) 2013,2014 Linaro Limited
+ *     Roy Franz <roy.franz@linaro.org
+ * Copyright (C) 2013 Red Hat, Inc.
+ *     Mark Salter <msalter@redhat.com>
+ *
+ * This file is part of the Linux kernel, and is made available under the
+ * terms of the GNU General Public License version 2.
+ */
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+/* BIOS variables */
+static const efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
+static const efi_char16_t const efi_SecureBoot_name[] = {
+	'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0
+};
+static const efi_char16_t const efi_SetupMode_name[] = {
+	'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0
+};
+
+#define get_efi_var(name, vendor, ...) \
+	efi_call_runtime(get_variable, \
+			 (efi_char16_t *)(name), (efi_guid_t *)(vendor), \
+			 __VA_ARGS__);
+
+/*
+ * Determine whether we're in secure boot mode.
+ */
+enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table_arg)
+{
+	u8 secboot, setupmode;
+	unsigned long size;
+	efi_status_t status;
+
+	size = sizeof(secboot);
+	status = get_efi_var(efi_SecureBoot_name, &efi_variable_guid,
+			     NULL, &size, &secboot);
+	if (status != EFI_SUCCESS)
+		goto out_efi_err;
+
+	size = sizeof(setupmode);
+	status = get_efi_var(efi_SetupMode_name, &efi_variable_guid,
+			     NULL, &size, &setupmode);
+	if (status != EFI_SUCCESS)
+		goto out_efi_err;
+
+	if (secboot == 0 || setupmode == 1)
+		return efi_secureboot_mode_disabled;
+
+	pr_efi(sys_table_arg, "UEFI Secure Boot is enabled.\n");
+	return efi_secureboot_mode_enabled;
+
+out_efi_err:
+	pr_efi_err(sys_table_arg, "Could not determine UEFI Secure Boot status.\n");
+	if (status == EFI_NOT_FOUND)
+		return efi_secureboot_mode_disabled;
+	return efi_secureboot_mode_unknown;
+}
diff --git a/include/linux/efi.h b/include/linux/efi.h
index d00538a..94d34e0 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1480,6 +1480,14 @@ efi_status_t efi_setup_gop(efi_system_table_t *sys_table_arg,
 bool efi_runtime_disabled(void);
 extern void efi_call_virt_check_flags(unsigned long flags, const char *call);
 
+enum efi_secureboot_mode {
+	efi_secureboot_mode_unset,
+	efi_secureboot_mode_unknown,
+	efi_secureboot_mode_disabled,
+	efi_secureboot_mode_enabled,
+};
+enum efi_secureboot_mode efi_get_secureboot(efi_system_table_t *sys_table);
+
 /*
  * Arch code can implement the following three template macros, avoiding
  * reptition for the void/non-void return cases of {__,}efi_call_virt():

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#1574572 — [PATCH 1/7] x86/efi: Allow invocation of arbitrary runtime services

FromArd Biesheuvel <ard.biesheuvel@linaro.org>
Date2017-02-06 12:30 +0100
Subject[PATCH 1/7] x86/efi: Allow invocation of arbitrary runtime services
Message-ID<t7PED-4iF-35@gated-at.bofh.it>
In reply to#1574568
From: David Howells <dhowells@redhat.com>

Provide the ability to perform mixed-mode runtime service calls for x86 in
the same way that commit 0a637ee61247bd4bed9b2a07568ef7a1cfc76187
("x86/efi: Allow invocation of arbitrary boot services") provides the
ability to invoke arbitrary boot services.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/boot/compressed/eboot.c   | 1 +
 arch/x86/boot/compressed/head_32.S | 6 +++---
 arch/x86/boot/compressed/head_64.S | 8 ++++----
 arch/x86/include/asm/efi.h         | 5 +++++
 4 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 6d3aeabbce68..f99978db6b6f 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -32,6 +32,7 @@ static void setup_boot_services##bits(struct efi_config *c)		\
 									\
 	table = (typeof(table))sys_table;				\
 									\
+	c->runtime_services = table->runtime;				\
 	c->boot_services = table->boottime;				\
 	c->text_output = table->con_out;				\
 }
diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index fd0b6a272dd5..d85b9625e836 100644
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -82,7 +82,7 @@ ENTRY(efi_pe_entry)
 
 	/* Relocate efi_config->call() */
 	leal	efi32_config(%esi), %eax
-	add	%esi, 32(%eax)
+	add	%esi, 40(%eax)
 	pushl	%eax
 
 	call	make_boot_params
@@ -108,7 +108,7 @@ ENTRY(efi32_stub_entry)
 
 	/* Relocate efi_config->call() */
 	leal	efi32_config(%esi), %eax
-	add	%esi, 32(%eax)
+	add	%esi, 40(%eax)
 	pushl	%eax
 2:
 	call	efi_main
@@ -264,7 +264,7 @@ relocated:
 #ifdef CONFIG_EFI_STUB
 	.data
 efi32_config:
-	.fill 4,8,0
+	.fill 5,8,0
 	.long efi_call_phys
 	.long 0
 	.byte 0
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 4d85e600db78..d2ae1f821e0c 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -264,7 +264,7 @@ ENTRY(efi_pe_entry)
 	/*
 	 * Relocate efi_config->call().
 	 */
-	addq	%rbp, efi64_config+32(%rip)
+	addq	%rbp, efi64_config+40(%rip)
 
 	movq	%rax, %rdi
 	call	make_boot_params
@@ -284,7 +284,7 @@ handover_entry:
 	 * Relocate efi_config->call().
 	 */
 	movq	efi_config(%rip), %rax
-	addq	%rbp, 32(%rax)
+	addq	%rbp, 40(%rax)
 2:
 	movq	efi_config(%rip), %rdi
 	call	efi_main
@@ -456,14 +456,14 @@ efi_config:
 #ifdef CONFIG_EFI_MIXED
 	.global efi32_config
 efi32_config:
-	.fill	4,8,0
+	.fill	5,8,0
 	.quad	efi64_thunk
 	.byte	0
 #endif
 
 	.global efi64_config
 efi64_config:
-	.fill	4,8,0
+	.fill	5,8,0
 	.quad	efi_call
 	.byte	1
 #endif /* CONFIG_EFI_STUB */
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index e99675b9c861..2f77bcefe6b4 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -191,6 +191,7 @@ static inline efi_status_t efi_thunk_set_virtual_address_map(
 struct efi_config {
 	u64 image_handle;
 	u64 table;
+	u64 runtime_services;
 	u64 boot_services;
 	u64 text_output;
 	efi_status_t (*call)(unsigned long, ...);
@@ -226,6 +227,10 @@ static inline bool efi_is_64bit(void)
 #define __efi_call_early(f, ...)					\
 	__efi_early()->call((unsigned long)f, __VA_ARGS__);
 
+#define efi_call_runtime(f, ...)					\
+	__efi_early()->call(efi_table_attr(efi_runtime_services, f,	\
+		__efi_early()->runtime_services), __VA_ARGS__)
+
 extern bool efi_reboot_required(void);
 
 #else
-- 
2.7.4

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#1575527 — [tip:efi/core] x86/efi: Allow invocation of arbitrary runtime services

Fromtip-bot for David Howells <tipbot@zytor.com>
Date2017-02-07 10:50 +0100
Subject[tip:efi/core] x86/efi: Allow invocation of arbitrary runtime services
Message-ID<t8azo-16x-35@gated-at.bofh.it>
In reply to#1574572
Commit-ID:  a2cd2f3f29f26782b7484b32e2af172e29313717
Gitweb:     http://git.kernel.org/tip/a2cd2f3f29f26782b7484b32e2af172e29313717
Author:     David Howells <dhowells@redhat.com>
AuthorDate: Mon, 6 Feb 2017 11:22:40 +0000
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 7 Feb 2017 10:42:09 +0100

x86/efi: Allow invocation of arbitrary runtime services

Provide the ability to perform mixed-mode runtime service calls for x86 in
the same way the following commit provided the ability to invoke for boot
services:

  0a637ee61247bd ("x86/efi: Allow invocation of arbitrary boot services")

Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1486380166-31868-2-git-send-email-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/boot/compressed/eboot.c   | 1 +
 arch/x86/boot/compressed/head_32.S | 6 +++---
 arch/x86/boot/compressed/head_64.S | 8 ++++----
 arch/x86/include/asm/efi.h         | 5 +++++
 4 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index 6d3aeab..f99978d 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -32,6 +32,7 @@ static void setup_boot_services##bits(struct efi_config *c)		\
 									\
 	table = (typeof(table))sys_table;				\
 									\
+	c->runtime_services = table->runtime;				\
 	c->boot_services = table->boottime;				\
 	c->text_output = table->con_out;				\
 }
diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index fd0b6a2..d85b962 100644
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -82,7 +82,7 @@ ENTRY(efi_pe_entry)
 
 	/* Relocate efi_config->call() */
 	leal	efi32_config(%esi), %eax
-	add	%esi, 32(%eax)
+	add	%esi, 40(%eax)
 	pushl	%eax
 
 	call	make_boot_params
@@ -108,7 +108,7 @@ ENTRY(efi32_stub_entry)
 
 	/* Relocate efi_config->call() */
 	leal	efi32_config(%esi), %eax
-	add	%esi, 32(%eax)
+	add	%esi, 40(%eax)
 	pushl	%eax
 2:
 	call	efi_main
@@ -264,7 +264,7 @@ relocated:
 #ifdef CONFIG_EFI_STUB
 	.data
 efi32_config:
-	.fill 4,8,0
+	.fill 5,8,0
 	.long efi_call_phys
 	.long 0
 	.byte 0
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 4d85e60..d2ae1f8 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -264,7 +264,7 @@ ENTRY(efi_pe_entry)
 	/*
 	 * Relocate efi_config->call().
 	 */
-	addq	%rbp, efi64_config+32(%rip)
+	addq	%rbp, efi64_config+40(%rip)
 
 	movq	%rax, %rdi
 	call	make_boot_params
@@ -284,7 +284,7 @@ handover_entry:
 	 * Relocate efi_config->call().
 	 */
 	movq	efi_config(%rip), %rax
-	addq	%rbp, 32(%rax)
+	addq	%rbp, 40(%rax)
 2:
 	movq	efi_config(%rip), %rdi
 	call	efi_main
@@ -456,14 +456,14 @@ efi_config:
 #ifdef CONFIG_EFI_MIXED
 	.global efi32_config
 efi32_config:
-	.fill	4,8,0
+	.fill	5,8,0
 	.quad	efi64_thunk
 	.byte	0
 #endif
 
 	.global efi64_config
 efi64_config:
-	.fill	4,8,0
+	.fill	5,8,0
 	.quad	efi_call
 	.byte	1
 #endif /* CONFIG_EFI_STUB */
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index e99675b..2f77bce 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -191,6 +191,7 @@ static inline efi_status_t efi_thunk_set_virtual_address_map(
 struct efi_config {
 	u64 image_handle;
 	u64 table;
+	u64 runtime_services;
 	u64 boot_services;
 	u64 text_output;
 	efi_status_t (*call)(unsigned long, ...);
@@ -226,6 +227,10 @@ static inline bool efi_is_64bit(void)
 #define __efi_call_early(f, ...)					\
 	__efi_early()->call((unsigned long)f, __VA_ARGS__);
 
+#define efi_call_runtime(f, ...)					\
+	__efi_early()->call(efi_table_attr(efi_runtime_services, f,	\
+		__efi_early()->runtime_services), __VA_ARGS__)
+
 extern bool efi_reboot_required(void);
 
 #else

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