linux-kernel - [PATCH v10 4/9] powerpc/ima: define trusted boot policy

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Message-Id: <1572492694-6520-5-git-send-email-zohar@linux.ibm.com>
Date:   Wed, 30 Oct 2019 23:31:29 -0400
From:   Mimi Zohar <zohar@...ux.ibm.com>
To:     linuxppc-dev@...abs.org, linux-efi@...r.kernel.org,
        linux-integrity@...r.kernel.org
Cc:     Nayna Jain <nayna@...ux.ibm.com>, linux-kernel@...r.kernel.org,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Jeremy Kerr <jk@...abs.org>,
        Eric Ricther <erichte@...ux.ibm.com>,
        "Oliver O'Halloran" <oohall@...il.com>,
        Mimi Zohar <zohar@...ux.ibm.com>
Subject: [PATCH v10 4/9] powerpc/ima: define trusted boot policy

From: Nayna Jain <nayna@...ux.ibm.com>

This patch defines an arch-specific trusted boot only policy and a
combined secure and trusted boot policy.

Signed-off-by: Nayna Jain <nayna@...ux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@...ux.ibm.com>
---
 arch/powerpc/kernel/ima_arch.c | 33 ++++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/ima_arch.c b/arch/powerpc/kernel/ima_arch.c
index d88913dc0da7..0ef5956c9753 100644
--- a/arch/powerpc/kernel/ima_arch.c
+++ b/arch/powerpc/kernel/ima_arch.c
@@ -31,13 +31,44 @@ static const char *const secure_rules[] = {
 };
 
 /*
+ * 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_type=imasig|modsig",
+#ifndef CONFIG_MODULE_SIG_FORCE
+	"appraise func=MODULE_CHECK 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())
-		return secure_rules;
+		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;
 }
-- 
2.7.5