1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
From: David Howells <dhowells@redhat.com>
Date: Mon, 18 Feb 2019 12:45:03 +0000
Subject: [28/30] efi: Add an EFI_SECURE_BOOT flag to indicate secure boot mode
Origin: https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit?id=a5d70c55c603233c192b375f72116a395909da28
UEFI machines can be booted in Secure Boot mode. Add an EFI_SECURE_BOOT
flag that can be passed to efi_enabled() to find out whether secure boot is
enabled.
Move the switch-statement in x86's setup_arch() that inteprets the
secure_boot boot parameter to generic code and set the bit there.
Suggested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
cc: linux-efi@vger.kernel.org
[rperier: Forward-ported to 5.5:
- Use pr_warn()
- Adjust context]
[bwh: Forward-ported to 5.6: adjust context]
[bwh: Forward-ported to 5.7:
- Use the next available bit in efi.flags
- Adjust context]
---
arch/x86/kernel/setup.c | 14 +----------
drivers/firmware/efi/Makefile | 1 +
drivers/firmware/efi/secureboot.c | 39 +++++++++++++++++++++++++++++++
include/linux/efi.h | 16 ++++++++-----
4 files changed, 51 insertions(+), 19 deletions(-)
create mode 100644 drivers/firmware/efi/secureboot.c
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1205,19 +1205,7 @@ void __init setup_arch(char **cmdline_p)
/* Allocate bigger log buffer */
setup_log_buf(1);
- if (efi_enabled(EFI_BOOT)) {
- switch (boot_params.secure_boot) {
- case efi_secureboot_mode_disabled:
- pr_info("Secure boot disabled\n");
- break;
- case efi_secureboot_mode_enabled:
- pr_info("Secure boot enabled\n");
- break;
- default:
- pr_info("Secure boot could not be determined\n");
- break;
- }
- }
+ efi_set_secure_boot(boot_params.secure_boot);
reserve_initrd();
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_EFI_FAKE_MEMMAP) += fake_m
obj-$(CONFIG_EFI_BOOTLOADER_CONTROL) += efibc.o
obj-$(CONFIG_EFI_TEST) += test/
obj-$(CONFIG_EFI_DEV_PATH_PARSER) += dev-path-parser.o
+obj-$(CONFIG_EFI) += secureboot.o
obj-$(CONFIG_APPLE_PROPERTIES) += apple-properties.o
obj-$(CONFIG_EFI_RCI2_TABLE) += rci2-table.o
obj-$(CONFIG_EFI_EMBEDDED_FIRMWARE) += embedded-firmware.o
--- /dev/null
+++ b/drivers/firmware/efi/secureboot.c
@@ -0,0 +1,39 @@
+
+/* Core kernel secure boot support.
+ *
+ * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/efi.h>
+#include <linux/kernel.h>
+#include <linux/printk.h>
+
+/*
+ * Decide what to do when UEFI secure boot mode is enabled.
+ */
+void __init efi_set_secure_boot(enum efi_secureboot_mode mode)
+{
+ if (efi_enabled(EFI_BOOT)) {
+ switch (mode) {
+ case efi_secureboot_mode_disabled:
+ pr_info("Secure boot disabled\n");
+ break;
+ case efi_secureboot_mode_enabled:
+ set_bit(EFI_SECURE_BOOT, &efi.flags);
+ pr_info("Secure boot enabled\n");
+ break;
+ default:
+ pr_warn("Secure boot could not be determined (mode %u)\n",
+ mode);
+ break;
+ }
+ }
+}
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -849,6 +849,14 @@ extern int __init efi_setup_pcdp_console
#define EFI_MEM_ATTR 10 /* Did firmware publish an EFI_MEMORY_ATTRIBUTES table? */
#define EFI_MEM_NO_SOFT_RESERVE 11 /* Is the kernel configured to ignore soft reservations? */
#define EFI_PRESERVE_BS_REGIONS 12 /* Are EFI boot-services memory segments available? */
+#define EFI_SECURE_BOOT 13 /* Are we in Secure Boot mode? */
+
+enum efi_secureboot_mode {
+ efi_secureboot_mode_unset,
+ efi_secureboot_mode_unknown,
+ efi_secureboot_mode_disabled,
+ efi_secureboot_mode_enabled,
+};
#ifdef CONFIG_EFI
/*
@@ -873,6 +881,7 @@ static inline bool efi_rt_services_suppo
return (efi.runtime_supported_mask & mask) == mask;
}
extern void efi_find_mirror(void);
+extern void __init efi_set_secure_boot(enum efi_secureboot_mode mode);
#else
static inline bool efi_enabled(int feature)
{
@@ -892,6 +901,7 @@ static inline bool efi_rt_services_suppo
}
static inline void efi_find_mirror(void) {}
+static inline void efi_set_secure_boot(enum efi_secureboot_mode mode) {}
#endif
extern int efi_status_to_err(efi_status_t status);
@@ -1107,13 +1117,6 @@ static inline bool efi_runtime_disabled(
extern void efi_call_virt_check_flags(unsigned long flags, const char *call);
extern unsigned long efi_call_virt_save_flags(void);
-enum efi_secureboot_mode {
- efi_secureboot_mode_unset,
- efi_secureboot_mode_unknown,
- efi_secureboot_mode_disabled,
- efi_secureboot_mode_enabled,
-};
-
static inline
enum efi_secureboot_mode efi_get_secureboot_mode(efi_get_variable_t *get_var)
{
|
