1 files changed, 78 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/ima_arch.c b/arch/powerpc/kernel/ima_arch.c
new file mode 100644
index 000000000000..e34116255ced
--- /dev/null
+++ b/arch/powerpc/kernel/ima_arch.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ */
+
+#include <linux/ima.h>
+#include <asm/secure_boot.h>
+
+bool arch_ima_get_secureboot(void)
+{
+	return is_ppc_secureboot_enabled();
+}
+
+/*
+ * The "secure_rules" are enabled only on "secureboot" enabled systems.
+ * These rules verify the file signatures against known good values.
+ * The "appraise_type=imasig|modsig" option allows the known good signature
+ * to be stored as an xattr or as an appended signature.
+ *
+ * To avoid duplicate signature verification as much as possible, the IMA
+ * policy rule for module appraisal is added only if CONFIG_MODULE_SIG_FORCE
+ * is not enabled.
+ */
+static const char *const secure_rules[] = {
+	"appraise func=KEXEC_KERNEL_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig",
+#ifndef CONFIG_MODULE_SIG_FORCE
+	"appraise func=MODULE_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig",
+#endif
+	NULL
+};
+
+/*
+ * The "trusted_rules" are enabled only on "trustedboot" enabled systems.
+ * These rules add the kexec kernel image and kernel modules file hashes to
+ * the IMA measurement list.
+ */
+static const char *const trusted_rules[] = {
+	"measure func=KEXEC_KERNEL_CHECK",
+	"measure func=MODULE_CHECK",
+	NULL
+};
+
+/*
+ * The "secure_and_trusted_rules" contains rules for both the secure boot and
+ * trusted boot. The "template=ima-modsig" option includes the appended
+ * signature, when available, in the IMA measurement list.
+ */
+static const char *const secure_and_trusted_rules[] = {
+	"measure func=KEXEC_KERNEL_CHECK template=ima-modsig",
+	"measure func=MODULE_CHECK template=ima-modsig",
+	"appraise func=KEXEC_KERNEL_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig",
+#ifndef CONFIG_MODULE_SIG_FORCE
+	"appraise func=MODULE_CHECK appraise_flag=check_blacklist appraise_type=imasig|modsig",
+#endif
+	NULL
+};
+
+/*
+ * Returns the relevant IMA arch-specific policies based on the system secure
+ * boot state.
+ */
+const char *const *arch_get_ima_policy(void)
+{
+	if (is_ppc_secureboot_enabled()) {
+		if (IS_ENABLED(CONFIG_MODULE_SIG))
+			set_module_sig_enforced();
+
+		if (is_ppc_trustedboot_enabled())
+			return secure_and_trusted_rules;
+		else
+			return secure_rules;
+	} else if (is_ppc_trustedboot_enabled()) {
+		return trusted_rules;
+	}
+
+	return NULL;
+}