ima: generalize x86/EFI arch glue for other EFI architectures

Move the x86 IMA arch code into security/integrity/ima/ima_efi.c,
so that we will be able to wire it up for arm64 in a future patch.

Co-developed-by: Chester Lin <clin@suse.com>
Signed-off-by: Chester Lin <clin@suse.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

3 files changed, 3 insertions, 96 deletions

diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index 7673dc833232..c98f78330b09 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -380,4 +380,7 @@ static inline void efi_fake_memmap_early(void)
 }
 #endif
 
+#define arch_ima_efi_boot_mode	\
+	({ extern struct boot_params boot_params; boot_params.secure_boot; })
+
 #endif /* _ASM_X86_EFI_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 68608bd892c0..5eeb808eb024 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -161,5 +161,3 @@ ifeq ($(CONFIG_X86_64),y)
 	obj-$(CONFIG_MMCONF_FAM10H)	+= mmconf-fam10h_64.o
 	obj-y				+= vsmp_64.o
 endif
-
-obj-$(CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT)	+= ima_arch.o
diff --git a/arch/x86/kernel/ima_arch.c b/arch/x86/kernel/ima_arch.c
deleted file mode 100644
index 7dfb1e808928..000000000000
--- a/arch/x86/kernel/ima_arch.c
+++ /dev/null
@@ -1,94 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0+ */
-/*
- * Copyright (C) 2018 IBM Corporation
- */
-#include <linux/efi.h>
-#include <linux/module.h>
-#include <linux/ima.h>
-
-extern struct boot_params boot_params;
-
-static enum efi_secureboot_mode get_sb_mode(void)
-{
-	efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID;
-	efi_status_t status;
-	unsigned long size;
-	u8 secboot, setupmode;
-
-	size = sizeof(secboot);
-
-	if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE)) {
-		pr_info("ima: secureboot mode unknown, no efi\n");
-		return efi_secureboot_mode_unknown;
-	}
-
-	/* Get variable contents into buffer */
-	status = efi.get_variable(L"SecureBoot", &efi_variable_guid,
-				  NULL, &size, &secboot);
-	if (status == EFI_NOT_FOUND) {
-		pr_info("ima: secureboot mode disabled\n");
-		return efi_secureboot_mode_disabled;
-	}
-
-	if (status != EFI_SUCCESS) {
-		pr_info("ima: secureboot mode unknown\n");
-		return efi_secureboot_mode_unknown;
-	}
-
-	size = sizeof(setupmode);
-	status = efi.get_variable(L"SetupMode", &efi_variable_guid,
-				  NULL, &size, &setupmode);
-
-	if (status != EFI_SUCCESS)	/* ignore unknown SetupMode */
-		setupmode = 0;
-
-	if (secboot == 0 || setupmode == 1) {
-		pr_info("ima: secureboot mode disabled\n");
-		return efi_secureboot_mode_disabled;
-	}
-
-	pr_info("ima: secureboot mode enabled\n");
-	return efi_secureboot_mode_enabled;
-}
-
-bool arch_ima_get_secureboot(void)
-{
-	static enum efi_secureboot_mode sb_mode;
-	static bool initialized;
-
-	if (!initialized && efi_enabled(EFI_BOOT)) {
-		sb_mode = boot_params.secure_boot;
-
-		if (sb_mode == efi_secureboot_mode_unset)
-			sb_mode = get_sb_mode();
-		initialized = true;
-	}
-
-	if (sb_mode == efi_secureboot_mode_enabled)
-		return true;
-	else
-		return false;
-}
-
-/* secureboot arch rules */
-static const char * const sb_arch_rules[] = {
-#if !IS_ENABLED(CONFIG_KEXEC_SIG)
-	"appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig",
-#endif /* CONFIG_KEXEC_SIG */
-	"measure func=KEXEC_KERNEL_CHECK",
-#if !IS_ENABLED(CONFIG_MODULE_SIG)
-	"appraise func=MODULE_CHECK appraise_type=imasig",
-#endif
-	"measure func=MODULE_CHECK",
-	NULL
-};
-
-const char * const *arch_get_ima_policy(void)
-{
-	if (IS_ENABLED(CONFIG_IMA_ARCH_POLICY) && arch_ima_get_secureboot()) {
-		if (IS_ENABLED(CONFIG_MODULE_SIG))
-			set_module_sig_enforced();
-		return sb_arch_rules;
-	}
-	return NULL;
-}