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

Daniel Axtens
2020-07-17T05:58:11Z

Michal Suchánek <msuchanek@suse.de> writes:

> 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?

I'm not quite sure what you mean? They'll be documented in a future
revision of the PAPR, once I get my act together and submit the
relevant internal paperwork.

Daniel
>
> 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
>>