mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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99d5cadfde
This is a preparatory patch for kexec_file_load() lockdown. A locked down kernel needs to prevent unsigned kernel images from being loaded with kexec_file_load(). Currently, the only way to force the signature verification is compiling with KEXEC_VERIFY_SIG. This prevents loading usigned images even when the kernel is not locked down at runtime. This patch splits KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE. Analogous to the MODULE_SIG and MODULE_SIG_FORCE for modules, KEXEC_SIG turns on the signature verification but allows unsigned images to be loaded. KEXEC_SIG_FORCE disallows images without a valid signature. Signed-off-by: Jiri Bohac <jbohac@suse.cz> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Matthew Garrett <mjg59@google.com> cc: kexec@lists.infradead.org Signed-off-by: James Morris <jmorris@namei.org>
89 lines
2.1 KiB
C
89 lines
2.1 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/module.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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if (!efi_enabled(EFI_RUNTIME_SERVICES)) {
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pr_info("ima: secureboot mode unknown, no efi\n");
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return efi_secureboot_mode_unknown;
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}
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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_SIG)
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"appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig",
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#endif /* CONFIG_KEXEC_SIG */
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"measure func=KEXEC_KERNEL_CHECK",
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#if !IS_ENABLED(CONFIG_MODULE_SIG)
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"appraise func=MODULE_CHECK appraise_type=imasig",
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#endif
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"measure func=MODULE_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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if (IS_ENABLED(CONFIG_MODULE_SIG))
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set_module_sig_enforced();
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return sb_arch_rules;
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}
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return NULL;
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}
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