[PATCH v3 3/3] arm64/ima: add ima_arch support

Chester Lin
2020-10-30T06:09:38Z

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

Signed-off-by: Chester Lin <clin@suse.com>
---
arch/arm64/Kconfig | 1 +
arch/arm64/kernel/Makefile | 2 ++
arch/arm64/kernel/ima_arch.c | 43 ++++++++++++++++++++++++++++++++++++
3 files changed, 46 insertions(+)
create mode 100644 arch/arm64/kernel/ima_arch.c

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index a42e8d13cc88..496a4a26afc6 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -201,6 +201,7 @@ 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..564236d77adc
--- /dev/null
+++ b/arch/arm64/kernel/ima_arch.c
@@ -0,0 +1,43 @@
+// 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 bool sb_enabled;
+ static bool initialized;
+
+ if (!initialized & efi_enabled(EFI_BOOT)) {
+ sb_enabled = ima_get_efi_secureboot();
+ initialized = true;
+ }
+
+ return sb_enabled;
+}
+
+/* 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;
+}
--
2.28.0