Re: [PATCH v3] powerpc/pseries: detect secure and trusted boot state of the system.

Michal Suchánek
2020-07-16T08:13:42Z

On Wed, Jul 15, 2020 at 07:52:01AM -0400, Nayna Jain wrote:
> The device-tree property to check secure and trusted boot state is
> different for guests(pseries) compared to baremetal(powernv).
>
> This patch updates the existing is_ppc_secureboot_enabled() and
> is_ppc_trustedboot_enabled() functions to add support for pseries.
>
> The secureboot and trustedboot state are exposed via device-tree property:
> /proc/device-tree/ibm,secure-boot and /proc/device-tree/ibm,trusted-boot
>
> The values of ibm,secure-boot under pseries are interpreted as:
^^^
>
> 0 - Disabled
> 1 - Enabled in Log-only mode. This patch interprets this value as
> disabled, since audit mode is currently not supported for Linux.
> 2 - Enabled and enforced.
> 3-9 - Enabled and enforcing; requirements are at the discretion of the
> operating system.
>
> The values of ibm,trusted-boot under pseries are interpreted as:
^^^
These two should be different I suppose?

Thanks

Michal
> 0 - Disabled
> 1 - Enabled
>
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> Reviewed-by: Daniel Axtens <dja@axtens.net>
> ---
> v3:
> * fixed double check. Thanks Daniel for noticing it.
> * updated patch description.
>
> v2:
> * included Michael Ellerman's feedback.
> * added Daniel Axtens's Reviewed-by.
>
> arch/powerpc/kernel/secure_boot.c | 19 +++++++++++++++++--
> 1 file changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kernel/secure_boot.c b/arch/powerpc/kernel/secure_boot.c
> index 4b982324d368..118bcb5f79c4 100644
> --- a/arch/powerpc/kernel/secure_boot.c
> +++ b/arch/powerpc/kernel/secure_boot.c
> @@ -6,6 +6,7 @@
> #include <linux/types.h>
> #include <linux/of.h>
> #include <asm/secure_boot.h>
> +#include <asm/machdep.h>
>
> static struct device_node *get_ppc_fw_sb_node(void)
> {
> @@ -23,12 +24,19 @@ bool is_ppc_secureboot_enabled(void)
> {
> struct device_node *node;
> bool enabled = false;
> + u32 secureboot;
>
> node = get_ppc_fw_sb_node();
> enabled = of_property_read_bool(node, "os-secureboot-enforcing");
> -
> of_node_put(node);
>
> + if (enabled)
> + goto out;
> +
> + if (!of_property_read_u32(of_root, "ibm,secure-boot", &secureboot))
> + enabled = (secureboot > 1);
> +
> +out:
> pr_info("Secure boot mode %s\n", enabled ? "enabled" : "disabled");
>
> return enabled;
> @@ -38,12 +46,19 @@ bool is_ppc_trustedboot_enabled(void)
> {
> struct device_node *node;
> bool enabled = false;
> + u32 trustedboot;
>
> node = get_ppc_fw_sb_node();
> enabled = of_property_read_bool(node, "trusted-enabled");
> -
> of_node_put(node);
>
> + if (enabled)
> + goto out;
> +
> + if (!of_property_read_u32(of_root, "ibm,trusted-boot", &trustedboot))
> + enabled = (trustedboot > 0);
> +
> +out:
> pr_info("Trusted boot mode %s\n", enabled ? "enabled" : "disabled");
>
> return enabled;
> --
> 2.26.2
>