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

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

[Nayna Jain]

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() function to add support for pseries.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
---
 arch/powerpc/kernel/secure_boot.c | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/secure_boot.c b/arch/powerpc/kernel/secure_boot.c
index 4b982324d368..43fc6607c7a5 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)
 {
@@ -23,11 +24,20 @@ bool is_ppc_secureboot_enabled(void)
 {
 	struct device_node *node;
 	bool enabled = false;
+	const u32 *secureboot;
 
-	node = get_ppc_fw_sb_node();
-	enabled = of_property_read_bool(node, "os-secureboot-enforcing");
+	if (machine_is(powernv)) {
+		node = get_ppc_fw_sb_node();
+		enabled =
+		    of_property_read_bool(node, "os-secureboot-enforcing");
+		of_node_put(node);
+	}
 
-	of_node_put(node);
+	if (machine_is(pseries)) {
+		secureboot = of_get_property(of_root, "ibm,secure-boot", NULL);
+		if (secureboot)
+			enabled = (*secureboot > 1) ? true : false;
+	}
 
 	pr_info("Secure boot mode %s\n", enabled ? "enabled" : "disabled");
 
@@ -38,11 +48,20 @@ bool is_ppc_trustedboot_enabled(void)
 {
 	struct device_node *node;
 	bool enabled = false;
+	const u32 *trustedboot;
 
-	node = get_ppc_fw_sb_node();
-	enabled = of_property_read_bool(node, "trusted-enabled");
+	if (machine_is(powernv)) {
+		node = get_ppc_fw_sb_node();
+		enabled = of_property_read_bool(node, "trusted-enabled");
+		of_node_put(node);
+	}
 
-	of_node_put(node);
+	if (machine_is(pseries)) {
+		trustedboot =
+		    of_get_property(of_root, "ibm,trusted-boot", NULL);
+		if (trustedboot)
+			enabled = (*trustedboot > 0) ? true : false;
+	}
 
 	pr_info("Trusted boot mode %s\n", enabled ? "enabled" : "disabled");
 
-- 
2.18.1

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

[Daniel Axtens]

Thanks Nayna!

I'm hoping to get better public documentation for this soon as it's not
documented in a public PAPR yet.

Until then:

The values of ibm,secure-boot under PowerVM are:

 0 - disabled
 
 1 - audit mode only. This patch ignores this value for Linux, which I
     think is the appropriate thing to do.

 2 - enabled and enforcing

 3-9 - enabled, OS-defined behaviour. In this patch we map all these
       values to enabled and enforcing. Again I think this is the
       appropriate thing to do.

ibm,trusted-boot isn't published by a current PowerVM LPAR but will be
published in future. (Currently, trusted boot state is inferred by the
presence or absense of a vTPM.) It's simply 1 = enabled, 0 = disabled.

As for this patch specifically, with the very small nits below,

Reviewed-by: Daniel Axtens <dja@axtens.net>

> -	node = get_ppc_fw_sb_node();
> -	enabled = of_property_read_bool(node, "os-secureboot-enforcing");
> +	if (machine_is(powernv)) {
> +		node = get_ppc_fw_sb_node();
> +		enabled =
> +		    of_property_read_bool(node, "os-secureboot-enforcing");
> +		of_node_put(node);
> +	}
>  
> -	of_node_put(node);
> +	if (machine_is(pseries)) {
Maybe this should be an else if?

> +		secureboot = of_get_property(of_root, "ibm,secure-boot", NULL);
> +		if (secureboot)
> +			enabled = (*secureboot > 1) ? true : false;
> +	}
>  
>  	pr_info("Secure boot mode %s\n", enabled ? "enabled" : "disabled");
>  
> @@ -38,11 +48,20 @@ bool is_ppc_trustedboot_enabled(void)
>  {
>  	struct device_node *node;
>  	bool enabled = false;
> +	const u32 *trustedboot;
>  
> -	node = get_ppc_fw_sb_node();
> -	enabled = of_property_read_bool(node, "trusted-enabled");
> +	if (machine_is(powernv)) {
> +		node = get_ppc_fw_sb_node();
> +		enabled = of_property_read_bool(node, "trusted-enabled");
> +		of_node_put(node);
> +	}
>  
> -	of_node_put(node);
> +	if (machine_is(pseries)) {
Likewise.
> +		trustedboot =
> +		    of_get_property(of_root, "ibm,trusted-boot", NULL);
> +		if (trustedboot)
> +			enabled = (*trustedboot > 0) ? true : false;

Regards,
Daniel

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

[Daniel Axtens]

As a final extra note,

  https://github.com/daxtens/qemu/tree/pseries-secboot

is a qemu repository that fakes out the relevant properties if anyone
else wants to test this.

Also,

>  3-9 - enabled, OS-defined behaviour. In this patch we map all these
>        values to enabled and enforcing. Again I think this is the
>        appropriate thing to do.

this should read "enabled and enforcing, requirements are at the
discretion of the operating system". Apologies.

Regards,
Daniel

> ibm,trusted-boot isn't published by a current PowerVM LPAR but will be
> published in future. (Currently, trusted boot state is inferred by the
> presence or absense of a vTPM.) It's simply 1 = enabled, 0 = disabled.
>
> As for this patch specifically, with the very small nits below,
>
> Reviewed-by: Daniel Axtens <dja@axtens.net>
>
>> -	node = get_ppc_fw_sb_node();
>> -	enabled = of_property_read_bool(node, "os-secureboot-enforcing");
>> +	if (machine_is(powernv)) {
>> +		node = get_ppc_fw_sb_node();
>> +		enabled =
>> +		    of_property_read_bool(node, "os-secureboot-enforcing");
>> +		of_node_put(node);
>> +	}
>>  
>> -	of_node_put(node);
>> +	if (machine_is(pseries)) {
> Maybe this should be an else if?
>
>> +		secureboot = of_get_property(of_root, "ibm,secure-boot", NULL);
>> +		if (secureboot)
>> +			enabled = (*secureboot > 1) ? true : false;
>> +	}
>>  
>>  	pr_info("Secure boot mode %s\n", enabled ? "enabled" : "disabled");
>>  
>> @@ -38,11 +48,20 @@ bool is_ppc_trustedboot_enabled(void)
>>  {
>>  	struct device_node *node;
>>  	bool enabled = false;
>> +	const u32 *trustedboot;
>>  
>> -	node = get_ppc_fw_sb_node();
>> -	enabled = of_property_read_bool(node, "trusted-enabled");
>> +	if (machine_is(powernv)) {
>> +		node = get_ppc_fw_sb_node();
>> +		enabled = of_property_read_bool(node, "trusted-enabled");
>> +		of_node_put(node);
>> +	}
>>  
>> -	of_node_put(node);
>> +	if (machine_is(pseries)) {
> Likewise.
>> +		trustedboot =
>> +		    of_get_property(of_root, "ibm,trusted-boot", NULL);
>> +		if (trustedboot)
>> +			enabled = (*trustedboot > 0) ? true : false;
>
> Regards,
> Daniel

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

[Michael Ellerman]

Nayna Jain <nayna@linux.ibm.com> writes:
> 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() function to add support for pseries.
>
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> ---
>  arch/powerpc/kernel/secure_boot.c | 31 +++++++++++++++++++++++++------
>  1 file changed, 25 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/kernel/secure_boot.c b/arch/powerpc/kernel/secure_boot.c
> index 4b982324d368..43fc6607c7a5 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)
>  {
> @@ -23,11 +24,20 @@ bool is_ppc_secureboot_enabled(void)
>  {
>  	struct device_node *node;
>  	bool enabled = false;
> +	const u32 *secureboot;
>  
> -	node = get_ppc_fw_sb_node();
> -	enabled = of_property_read_bool(node, "os-secureboot-enforcing");
> +	if (machine_is(powernv)) {
> +		node = get_ppc_fw_sb_node();
> +		enabled =
> +		    of_property_read_bool(node, "os-secureboot-enforcing");
> +		of_node_put(node);
> +	}

We generally try to avoid adding new machine_is() checks if we can.

In a case like this I think you can just check for both properties
regardless of what platform you're on.
  
> -	of_node_put(node);
> +	if (machine_is(pseries)) {
> +		secureboot = of_get_property(of_root, "ibm,secure-boot", NULL);
> +		if (secureboot)
> +			enabled = (*secureboot > 1) ? true : false;
> +	}

Please don't use of_get_property() in new code. Use one of the properly
typed accessors that handles endian conversion for you.

cheers