399574c64e
The secure boot mode may not be detected on boot for some reason (eg. buggy firmware). This patch attempts one more time to detect the secure boot mode. Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
76 lines
1.7 KiB
C
76 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Copyright (C) 2018 IBM Corporation
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*/
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#include <linux/efi.h>
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#include <linux/ima.h>
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extern struct boot_params boot_params;
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static enum efi_secureboot_mode get_sb_mode(void)
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{
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efi_char16_t efi_SecureBoot_name[] = L"SecureBoot";
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efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
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efi_status_t status;
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unsigned long size;
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u8 secboot;
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size = sizeof(secboot);
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/* Get variable contents into buffer */
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status = efi.get_variable(efi_SecureBoot_name, &efi_variable_guid,
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NULL, &size, &secboot);
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if (status == EFI_NOT_FOUND) {
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pr_info("ima: secureboot mode disabled\n");
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return efi_secureboot_mode_disabled;
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}
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if (status != EFI_SUCCESS) {
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pr_info("ima: secureboot mode unknown\n");
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return efi_secureboot_mode_unknown;
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}
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if (secboot == 0) {
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pr_info("ima: secureboot mode disabled\n");
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return efi_secureboot_mode_disabled;
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}
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pr_info("ima: secureboot mode enabled\n");
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return efi_secureboot_mode_enabled;
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}
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bool arch_ima_get_secureboot(void)
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{
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static enum efi_secureboot_mode sb_mode;
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static bool initialized;
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if (!initialized && efi_enabled(EFI_BOOT)) {
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sb_mode = boot_params.secure_boot;
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if (sb_mode == efi_secureboot_mode_unset)
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sb_mode = get_sb_mode();
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initialized = true;
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}
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if (sb_mode == efi_secureboot_mode_enabled)
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return true;
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else
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return false;
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}
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/* secureboot arch rules */
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static const char * const sb_arch_rules[] = {
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#if !IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG)
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"appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig",
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#endif /* CONFIG_KEXEC_VERIFY_SIG */
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"measure func=KEXEC_KERNEL_CHECK",
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NULL
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};
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const char * const *arch_get_ima_policy(void)
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{
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if (IS_ENABLED(CONFIG_IMA_ARCH_POLICY) && arch_ima_get_secureboot())
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return sb_arch_rules;
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return NULL;
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}
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