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af16df54b8
Currently, an unsigned kernel could be kexec'ed when IMA arch specific
policy is configured unless lockdown is enabled. Enforce kernel
signature verification check in the kexec_file_load syscall when IMA
arch specific policy is configured.
Fixes: 99d5cadfde ("kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE")
Reported-and-suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Coiby Xu <coxu@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
76 lines
1.8 KiB
C
76 lines
1.8 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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#include <asm/efi.h>
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#ifndef arch_ima_efi_boot_mode
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#define arch_ima_efi_boot_mode efi_secureboot_mode_unset
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#endif
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static enum efi_secureboot_mode get_sb_mode(void)
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{
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enum efi_secureboot_mode mode;
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if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE)) {
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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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mode = efi_get_secureboot_mode(efi.get_variable);
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if (mode == efi_secureboot_mode_disabled)
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pr_info("ima: secureboot mode disabled\n");
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else if (mode == efi_secureboot_mode_unknown)
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pr_info("ima: secureboot mode unknown\n");
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else
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pr_info("ima: secureboot mode enabled\n");
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return mode;
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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 = arch_ima_efi_boot_mode;
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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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if (IS_ENABLED(CONFIG_KEXEC_SIG))
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set_kexec_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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