[PATCH 4/6] efi: Get the secure boot status
From: David Howells
Date: Mon Nov 21 2016 - 19:32:11 EST
Get the firmware's secure-boot status in the kernel boot wrapper and stash
it somewhere that the main kernel image can find.
Signed-off-by: Matthew Garrett <matthew.garrett@xxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---
Documentation/x86/zero-page.txt | 2 +
arch/x86/boot/compressed/eboot.c | 5 ++
arch/x86/include/uapi/asm/bootparam.h | 3 +
drivers/firmware/efi/libstub/Makefile | 2 -
drivers/firmware/efi/libstub/arm-stub.c | 46 --------------------
drivers/firmware/efi/libstub/secureboot.c | 66 +++++++++++++++++++++++++++++
include/linux/efi.h | 2 +
7 files changed, 78 insertions(+), 48 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 c8c32ebcdfdb..fd6506de480d 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -12,6 +12,7 @@
#include <asm/efi.h>
#include <asm/setup.h>
#include <asm/desc.h>
+#include <asm/bootparam_utils.h>
#include "../string.h"
#include "eboot.h"
@@ -1158,6 +1159,10 @@ struct boot_params *efi_main(struct efi_config *c,
else
setup_boot_services32(efi_early);
+ sanitize_boot_params(boot_params);
+
+ boot_params->secure_boot = efi_get_secureboot();
+
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/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 6621b13c370f..9af966863612 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 b4f7d78f9e8b..552ee61ddbed 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)
{
diff --git a/drivers/firmware/efi/libstub/secureboot.c b/drivers/firmware/efi/libstub/secureboot.c
new file mode 100644
index 000000000000..e44d8c9ee150
--- /dev/null
+++ b/drivers/firmware/efi/libstub/secureboot.c
@@ -0,0 +1,66 @@
+/*
+ * Secure boot handling.
+ *
+ * Copyright (C) 2013,2014 Linaro Limited
+ * Roy Franz <roy.franz@xxxxxxxxxx
+ * Copyright (C) 2013 Red Hat, Inc.
+ * Mark Salter <msalter@xxxxxxxxxx>
+ *
+ * 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 <linux/sort.h>
+#include <asm/efi.h>
+
+#include "efistub.h"
+
+int efi_get_secureboot(void)
+{
+ static const efi_char16_t const sb_var_name[] = {
+ 'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };
+ static const efi_char16_t const sm_var_name[] = {
+ 'S', 'e', 't', 'u', 'p', 'M', 'o', 'd', 'e', 0 };
+
+ static const efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID;
+
+ u8 val;
+ unsigned long size = sizeof(val);
+ efi_status_t status;
+
+#define f_getvar(...) efi_call_runtime(get_variable, __VA_ARGS__)
+
+ 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;
+ }
+}
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 24db4e5ec817..615d8704f048 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1477,6 +1477,8 @@ 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);
+int efi_get_secureboot(void);
+
/*
* Arch code can implement the following three template macros, avoiding
* reptition for the void/non-void return cases of {__,}efi_call_virt():