| David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 1 | /* SPDX-License-Identifier: GPL-2.0+ */ |
| 2 | /* |
| 3 | * Copyright (C) 2018 IBM Corporation |
| 4 | */ |
| 5 | #include <linux/efi.h> |
| 6 | #include <linux/module.h> |
| 7 | #include <linux/ima.h> |
| 8 | |
| 9 | extern struct boot_params boot_params; |
| 10 | |
| 11 | static enum efi_secureboot_mode get_sb_mode(void) |
| 12 | { |
| 13 | efi_char16_t efi_SecureBoot_name[] = L"SecureBoot"; |
| 14 | efi_char16_t efi_SetupMode_name[] = L"SecureBoot"; |
| 15 | efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID; |
| 16 | efi_status_t status; |
| 17 | unsigned long size; |
| 18 | u8 secboot, setupmode; |
| 19 | |
| 20 | size = sizeof(secboot); |
| 21 | |
| 22 | if (!efi_enabled(EFI_RUNTIME_SERVICES)) { |
| 23 | pr_info("ima: secureboot mode unknown, no efi\n"); |
| 24 | return efi_secureboot_mode_unknown; |
| 25 | } |
| 26 | |
| 27 | /* Get variable contents into buffer */ |
| 28 | status = efi.get_variable(efi_SecureBoot_name, &efi_variable_guid, |
| 29 | NULL, &size, &secboot); |
| 30 | if (status == EFI_NOT_FOUND) { |
| 31 | pr_info("ima: secureboot mode disabled\n"); |
| 32 | return efi_secureboot_mode_disabled; |
| 33 | } |
| 34 | |
| 35 | if (status != EFI_SUCCESS) { |
| 36 | pr_info("ima: secureboot mode unknown\n"); |
| 37 | return efi_secureboot_mode_unknown; |
| 38 | } |
| 39 | |
| 40 | size = sizeof(setupmode); |
| 41 | status = efi.get_variable(efi_SetupMode_name, &efi_variable_guid, |
| 42 | NULL, &size, &setupmode); |
| 43 | |
| 44 | if (status != EFI_SUCCESS) /* ignore unknown SetupMode */ |
| 45 | setupmode = 0; |
| 46 | |
| 47 | if (secboot == 0 || setupmode == 1) { |
| 48 | pr_info("ima: secureboot mode disabled\n"); |
| 49 | return efi_secureboot_mode_disabled; |
| 50 | } |
| 51 | |
| 52 | pr_info("ima: secureboot mode enabled\n"); |
| 53 | return efi_secureboot_mode_enabled; |
| 54 | } |
| 55 | |
| 56 | bool arch_ima_get_secureboot(void) |
| 57 | { |
| 58 | static enum efi_secureboot_mode sb_mode; |
| 59 | static bool initialized; |
| 60 | |
| 61 | if (!initialized && efi_enabled(EFI_BOOT)) { |
| 62 | sb_mode = boot_params.secure_boot; |
| 63 | |
| 64 | if (sb_mode == efi_secureboot_mode_unset) |
| 65 | sb_mode = get_sb_mode(); |
| 66 | initialized = true; |
| 67 | } |
| 68 | |
| 69 | if (sb_mode == efi_secureboot_mode_enabled) |
| 70 | return true; |
| 71 | else |
| 72 | return false; |
| 73 | } |
| 74 | |
| 75 | /* secureboot arch rules */ |
| 76 | static const char * const sb_arch_rules[] = { |
| 77 | #if !IS_ENABLED(CONFIG_KEXEC_SIG) |
| 78 | "appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig", |
| 79 | #endif /* CONFIG_KEXEC_SIG */ |
| 80 | "measure func=KEXEC_KERNEL_CHECK", |
| 81 | #if !IS_ENABLED(CONFIG_MODULE_SIG) |
| 82 | "appraise func=MODULE_CHECK appraise_type=imasig", |
| 83 | #endif |
| 84 | "measure func=MODULE_CHECK", |
| 85 | NULL |
| 86 | }; |
| 87 | |
| 88 | const char * const *arch_get_ima_policy(void) |
| 89 | { |
| 90 | if (IS_ENABLED(CONFIG_IMA_ARCH_POLICY) && arch_ima_get_secureboot()) { |
| 91 | if (IS_ENABLED(CONFIG_MODULE_SIG)) |
| 92 | set_module_sig_enforced(); |
| 93 | return sb_arch_rules; |
| 94 | } |
| 95 | return NULL; |
| 96 | } |