2019-10-24 19:11:53

by Nayna Jain

Subject: [PATCH v9 4/8] powerpc/ima: define trusted boot policy

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

Signed-off-by: Nayna Jain <[email protected]>
---
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
@@ -30,6 +30,32 @@ static const char *const secure_rules[] = {
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_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.
@@ -37,7 +63,12 @@ static const char *const secure_rules[] = {
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;
}
--
2.20.1

2019-10-25 18:48:55

by Lakshmi Ramasubramanian

Subject: Re: [PATCH v9 4/8] powerpc/ima: define trusted boot policy

On 10/23/2019 8:47 PM, Nayna Jain wrote:

> +/*
> + * 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
> +};

Same comment as earlier - any way to avoid using conditional compilation
in C file?

-lakshmi