[v2,2/2] arm64/ima: add ima_arch support

Commit Message

Chester Lin Oct. 14, 2020, 10:40 a.m. UTC

Add arm64 IMA arch support. The code and arch policy is mainly inherited
from x86.

Signed-off-by: Chester Lin <[e-mail]>
---
 arch/arm64/Kconfig           |  1 +
 arch/arm64/kernel/Makefile   |  2 ++
 arch/arm64/kernel/ima_arch.c | 46 ++++++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+)
 create mode 100644 arch/arm64/kernel/ima_arch.c

Patch

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 08fa3a1c50f0..15b7a3bbb7e5 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -199,6 +199,7 @@  config ARM64
 	select SWIOTLB
 	select SYSCTL_EXCEPTION_TRACE
 	select THREAD_INFO_IN_TASK
+	imply IMA_SECURE_AND_OR_TRUSTED_BOOT if EFI
 	help
 	  ARM 64-bit (AArch64) Linux support.
 
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index bbaf0bc4ad60..0f6cbb50668c 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -69,3 +69,5 @@  extra-y					+= $(head-y) vmlinux.lds
 ifeq ($(CONFIG_DEBUG_EFI),y)
 AFLAGS_head.o += -DVMLINUX_PATH="\"$(realpath $(objtree)/vmlinux)\""
 endif
+
+obj-$(CONFIG_IMA_SECURE_AND_OR_TRUSTED_BOOT)	+= ima_arch.o
diff --git a/arch/arm64/kernel/ima_arch.c b/arch/arm64/kernel/ima_arch.c
new file mode 100644
index 000000000000..f3103c8a2cab
--- /dev/null
+++ b/arch/arm64/kernel/ima_arch.c
@@ -0,0 +1,46 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 IBM Corporation
+ */
+#include <linux/efi.h>
+#include <linux/module.h>
+#include <linux/ima.h>
+
+bool arch_ima_get_secureboot(void)
+{
+	static enum efi_secureboot_mode sb_mode;
+	static bool initialized;
+
+	if (!initialized && efi_enabled(EFI_BOOT)) {
+		sb_mode = efi_get_secureboot_mode();
+		initialized = true;
+	}
+
+	if (sb_mode == efi_secureboot_mode_enabled)
+		return true;
+	else
+		return false;
+}
+
+/* secure and trusted boot 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;
+}