[PATCH v9 0/4] powerpc: expose secure variables to the kernel and userspace

[PATCH v9 0/4] powerpc: expose secure variables to the kernel and userspace

[Nayna Jain]

In order to verify the OS kernel on PowerNV systems, secure boot requires
X.509 certificates trusted by the platform. These are stored in secure
variables controlled by OPAL, called OPAL secure variables. In order to
enable users to manage the keys, the secure variables need to be exposed
to userspace.

OPAL provides the runtime services for the kernel to be able to access the
secure variables[1]. This patchset defines the kernel interface for the
OPAL APIs. These APIs are used by the hooks, which load these variables
to the keyring and expose them to the userspace for reading/writing.

The previous version[2] of the patchset added support only for the sysfs
interface. This patch adds two more patches that involves loading of
the firmware trusted keys to the kernel keyring.

Overall, this patchset adds the following support:

* expose secure variables to the kernel via OPAL Runtime API interface
* expose secure variables to the userspace via kernel sysfs interface
* load kernel verification and revocation keys to .platform and
.blacklist keyring respectively.

The secure variables can be read/written using simple linux utilities
cat/hexdump.

For example:
Path to the secure variables is:
/sys/firmware/secvar/vars

Each secure variable is listed as directory. 
$ ls -l
total 0
drwxr-xr-x. 2 root root 0 Aug 20 21:20 db
drwxr-xr-x. 2 root root 0 Aug 20 21:20 KEK
drwxr-xr-x. 2 root root 0 Aug 20 21:20 PK

The attributes of each of the secure variables are(for example: PK):
[db]$ ls -l
total 0
-r--r--r--. 1 root root  4096 Oct  1 15:10 data
-r--r--r--. 1 root root 65536 Oct  1 15:10 size
--w-------. 1 root root  4096 Oct  1 15:12 update

The "data" is used to read the existing variable value using hexdump. The
data is stored in ESL format.
The "update" is used to write a new value using cat. The update is
to be submitted as AUTH file.

[1] Depends on skiboot OPAL API changes which removes metadata from
the API. https://lists.ozlabs.org/pipermail/skiboot/2019-September/015203.html.
[2] https://lkml.org/lkml/2019/6/13/1644

Changelog:
v9:
* Updated Patch 1,2,4 to search secvar device tree node based on
generic compatible string.
* Renamed "backend" attribute to "format" attribute, and updated it
with the value of "format" property of secvar backend
* Updated Patch 4/4 to look for "format" property to ensure
edk2-compat-v1 variables format

v8
* rebased on v5.4-rc6
* Patch 2 related to sysfs
  * fixed error message as per Greg's feedback
  * fixed minor formatting 
  * renamed error code from ret to rc in backend_show()
* Patch 4 - loading of keys to keyring
  * as per Michael's feedback, removed select for LOAD_PPC_KEYS, instead
  made it default "yes" if the pre-requisites are satisfied
  * fixed an error message for more clarity

v7 (on behalf of Nayna, by Eric Richter):
* secvar-sysfs now a bool rather than a tristate option
* added documentation for backend sysfs entry

v6 (on behalf of Nayna, by Eric Richter):
* updated device tree layout
  * secvar node now sets compatible based on backend
  * all ibm,secvar-v1 compatible-checking code checks for
    ibm,edk2-compat-v1
* added backend attribute to secvar-sysfs to expose backend version to
  userspace
* loading certs from db now depends on backend (not all backends may
  have a "db")
* fixed device node leaks
* fixed leaking string on early exit

v5:
* rebased to v5.4-rc3
* includes Oliver's feedbacks
  * changed OPAL API as platform driver
  * sysfs are made default enabled and dependent on PPC_SECURE_BOOT
  * fixed code specific changes in both OPAL API and sysfs
  * reading size of the "data" and "update" file from device-tree.  
  * fixed sysfs documentation to also reflect the data and update file
  size interpretation
  * This patchset is no more dependent on ima-arch/blacklist patchset

v4:
* rebased to v5.4-rc1 
* uses __BIN_ATTR_WO macro to create binary attribute as suggested by
  Greg
* removed email id from the file header
* renamed argument keysize to keybufsize in get_next() function
* updated default binary file sizes to 0, as firmware handles checking
against the maximum size
* fixed minor formatting issues in Patch 4/4
* added Greg's and Mimi's Reviewed-by and Ack-by

v3:
* includes Greg's feedbacks:
 * fixes in Patch 2/4
   * updates the Documentation.
   * fixes code feedbacks
    * adds SYSFS Kconfig dependency for SECVAR_SYSFS
    * fixes mixed tabs and spaces
    * removes "name" attribute for each of the variable name based
    directories
    * fixes using __ATTR_RO() and __BIN_ATTR_RO() and statics and const
    * fixes the racing issue by using kobj_type default groups. Also,
    fixes the kobject leakage.
    * removes extra print messages
  * updates patch description for Patch 3/4
  * removes file name from Patch 4/4 file header comment and removed
  def_bool y from the LOAD_PPC_KEYS Kconfig

* includes Oliver's feedbacks:
  * fixes Patch 1/2
   * moves OPAL API wrappers after opal_nx_proc_init(), fixed the
   naming, types and removed extern.
   * fixes spaces
   * renames get_variable() to get(), get_next_variable() to get_next()
   and set_variable() to set()
   * removed get_secvar_ops() and defined secvar_ops as global
   * fixes consts and statics
   * removes generic secvar_init() and defined platform specific
   opal_secar_init()
   * updates opal_secvar_supported() to check for secvar support even
   before checking the OPAL APIs support and also fixed the error codes.
   * addes function that converts OPAL return codes to linux errno
   * moves secvar check support in the opal_secvar_init() and defined its
   prototype in opal.h
  * fixes Patch 2/2
   * fixes static/const
   * defines macro for max name size
   * replaces OPAL error codes with linux errno and also updated error
   handling
   * moves secvar support check before creating sysfs kobjects in 
   secvar_sysfs_init()
   * fixes spaces  

v2:
* removes complete efi-sms from the sysfs implementation and is simplified
* includes Greg's and Oliver's feedbacks:
 * adds sysfs documentation
 * moves sysfs code to arch/powerpc
 * other code related feedbacks.
* adds two new patches to load keys to .platform and .blacklist keyring.
These patches are added to this series as they are also dependent on
OPAL APIs.

Nayna Jain (4):
  powerpc/powernv: Add OPAL API interface to access secure variable
  powerpc: expose secure variables to userspace via sysfs
  x86/efi: move common keyring handler functions to new file
  powerpc: load firmware trusted keys/hashes into kernel keyring

 Documentation/ABI/testing/sysfs-secvar             |  46 ++++
 arch/powerpc/Kconfig                               |  11 +
 arch/powerpc/include/asm/opal-api.h                |   5 +-
 arch/powerpc/include/asm/opal.h                    |   7 +
 arch/powerpc/include/asm/secvar.h                  |  35 +++
 arch/powerpc/kernel/Makefile                       |   3 +-
 arch/powerpc/kernel/secvar-ops.c                   |  16 ++
 arch/powerpc/kernel/secvar-sysfs.c                 | 248 +++++++++++++++++++++
 arch/powerpc/platforms/powernv/Makefile            |   2 +-
 arch/powerpc/platforms/powernv/opal-call.c         |   3 +
 arch/powerpc/platforms/powernv/opal-secvar.c       | 140 ++++++++++++
 arch/powerpc/platforms/powernv/opal.c              |   3 +
 security/integrity/Kconfig                         |   9 +
 security/integrity/Makefile                        |   7 +-
 .../integrity/platform_certs/keyring_handler.c     |  80 +++++++
 .../integrity/platform_certs/keyring_handler.h     |  32 +++
 security/integrity/platform_certs/load_powerpc.c   |  99 ++++++++
 security/integrity/platform_certs/load_uefi.c      |  67 +-----
 18 files changed, 742 insertions(+), 71 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-secvar
 create mode 100644 arch/powerpc/include/asm/secvar.h
 create mode 100644 arch/powerpc/kernel/secvar-ops.c
 create mode 100644 arch/powerpc/kernel/secvar-sysfs.c
 create mode 100644 arch/powerpc/platforms/powernv/opal-secvar.c
 create mode 100644 security/integrity/platform_certs/keyring_handler.c
 create mode 100644 security/integrity/platform_certs/keyring_handler.h
 create mode 100644 security/integrity/platform_certs/load_powerpc.c

-- 
2.13.6

[PATCH v9 1/4] powerpc/powernv: Add OPAL API interface to access secure variable

[Nayna Jain]

The X.509 certificates trusted by the platform and required to secure boot
the OS kernel are wrapped in secure variables, which are controlled by
OPAL.

This patch adds firmware/kernel interface to read and write OPAL secure
variables based on the unique key.

This support can be enabled using CONFIG_OPAL_SECVAR.

Signed-off-by: Claudio Carvalho <cclaudio@linux.ibm.com>
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Eric Richter <erichte@linux.ibm.com>
---
 arch/powerpc/include/asm/opal-api.h          |   5 +-
 arch/powerpc/include/asm/opal.h              |   7 ++
 arch/powerpc/include/asm/secvar.h            |  35 +++++++
 arch/powerpc/kernel/Makefile                 |   2 +-
 arch/powerpc/kernel/secvar-ops.c             |  16 +++
 arch/powerpc/platforms/powernv/Makefile      |   2 +-
 arch/powerpc/platforms/powernv/opal-call.c   |   3 +
 arch/powerpc/platforms/powernv/opal-secvar.c | 140 +++++++++++++++++++++++++++
 arch/powerpc/platforms/powernv/opal.c        |   3 +
 9 files changed, 210 insertions(+), 3 deletions(-)
 create mode 100644 arch/powerpc/include/asm/secvar.h
 create mode 100644 arch/powerpc/kernel/secvar-ops.c
 create mode 100644 arch/powerpc/platforms/powernv/opal-secvar.c

diff --git a/arch/powerpc/include/asm/opal-api.h b/arch/powerpc/include/asm/opal-api.h
index 378e3997845a..c1f25a760eb1 100644
--- a/arch/powerpc/include/asm/opal-api.h
+++ b/arch/powerpc/include/asm/opal-api.h
@@ -211,7 +211,10 @@
 #define OPAL_MPIPL_UPDATE			173
 #define OPAL_MPIPL_REGISTER_TAG			174
 #define OPAL_MPIPL_QUERY_TAG			175
-#define OPAL_LAST				175
+#define OPAL_SECVAR_GET				176
+#define OPAL_SECVAR_GET_NEXT			177
+#define OPAL_SECVAR_ENQUEUE_UPDATE		178
+#define OPAL_LAST				178
 
 #define QUIESCE_HOLD			1 /* Spin all calls at entry */
 #define QUIESCE_REJECT			2 /* Fail all calls with OPAL_BUSY */
diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index a0cf8fba4d12..9986ac34b8e2 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -298,6 +298,13 @@ int opal_sensor_group_clear(u32 group_hndl, int token);
 int opal_sensor_group_enable(u32 group_hndl, int token, bool enable);
 int opal_nx_coproc_init(uint32_t chip_id, uint32_t ct);
 
+int opal_secvar_get(const char *key, uint64_t key_len, u8 *data,
+		    uint64_t *data_size);
+int opal_secvar_get_next(const char *key, uint64_t *key_len,
+			 uint64_t key_buf_size);
+int opal_secvar_enqueue_update(const char *key, uint64_t key_len, u8 *data,
+			       uint64_t data_size);
+
 s64 opal_mpipl_update(enum opal_mpipl_ops op, u64 src, u64 dest, u64 size);
 s64 opal_mpipl_register_tag(enum opal_mpipl_tags tag, u64 addr);
 s64 opal_mpipl_query_tag(enum opal_mpipl_tags tag, u64 *addr);
diff --git a/arch/powerpc/include/asm/secvar.h b/arch/powerpc/include/asm/secvar.h
new file mode 100644
index 000000000000..4cc35b58b986
--- /dev/null
+++ b/arch/powerpc/include/asm/secvar.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ *
+ * PowerPC secure variable operations.
+ */
+#ifndef SECVAR_OPS_H
+#define SECVAR_OPS_H
+
+#include <linux/types.h>
+#include <linux/errno.h>
+
+extern const struct secvar_operations *secvar_ops;
+
+struct secvar_operations {
+	int (*get)(const char *key, uint64_t key_len, u8 *data,
+		   uint64_t *data_size);
+	int (*get_next)(const char *key, uint64_t *key_len,
+			uint64_t keybufsize);
+	int (*set)(const char *key, uint64_t key_len, u8 *data,
+		   uint64_t data_size);
+};
+
+#ifdef CONFIG_PPC_SECURE_BOOT
+
+extern void set_secvar_ops(const struct secvar_operations *ops);
+
+#else
+
+static inline void set_secvar_ops(const struct secvar_operations *ops) { }
+
+#endif
+
+#endif
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index e8eb2955b7d5..3cf26427334f 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -161,7 +161,7 @@ ifneq ($(CONFIG_PPC_POWERNV)$(CONFIG_PPC_SVM),)
 obj-y				+= ucall.o
 endif
 
-obj-$(CONFIG_PPC_SECURE_BOOT)	+= secure_boot.o ima_arch.o
+obj-$(CONFIG_PPC_SECURE_BOOT)	+= secure_boot.o ima_arch.o secvar-ops.o
 
 # Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_prom_init.o := n
diff --git a/arch/powerpc/kernel/secvar-ops.c b/arch/powerpc/kernel/secvar-ops.c
new file mode 100644
index 000000000000..4cfa7dbd8850
--- /dev/null
+++ b/arch/powerpc/kernel/secvar-ops.c
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ *
+ * This file initializes secvar operations for PowerPC Secureboot
+ */
+
+#include <asm/secvar.h>
+
+const struct secvar_operations *secvar_ops;
+
+void set_secvar_ops(const struct secvar_operations *ops)
+{
+	secvar_ops = ops;
+}
diff --git a/arch/powerpc/platforms/powernv/Makefile b/arch/powerpc/platforms/powernv/Makefile
index a3ac9646119d..f9c4fa99e8b9 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -4,7 +4,7 @@ obj-y			+= idle.o opal-rtc.o opal-nvram.o opal-lpc.o opal-flash.o
 obj-y			+= rng.o opal-elog.o opal-dump.o opal-sysparam.o opal-sensor.o
 obj-y			+= opal-msglog.o opal-hmi.o opal-power.o opal-irqchip.o
 obj-y			+= opal-kmsg.o opal-powercap.o opal-psr.o opal-sensor-groups.o
-obj-y			+= ultravisor.o
+obj-y			+= ultravisor.o opal-secvar.o
 
 obj-$(CONFIG_SMP)	+= smp.o subcore.o subcore-asm.o
 obj-$(CONFIG_FA_DUMP)	+= opal-fadump.o
diff --git a/arch/powerpc/platforms/powernv/opal-call.c b/arch/powerpc/platforms/powernv/opal-call.c
index a2aa5e433ac8..5cd0f52d258f 100644
--- a/arch/powerpc/platforms/powernv/opal-call.c
+++ b/arch/powerpc/platforms/powernv/opal-call.c
@@ -290,3 +290,6 @@ OPAL_CALL(opal_nx_coproc_init,			OPAL_NX_COPROC_INIT);
 OPAL_CALL(opal_mpipl_update,			OPAL_MPIPL_UPDATE);
 OPAL_CALL(opal_mpipl_register_tag,		OPAL_MPIPL_REGISTER_TAG);
 OPAL_CALL(opal_mpipl_query_tag,			OPAL_MPIPL_QUERY_TAG);
+OPAL_CALL(opal_secvar_get,			OPAL_SECVAR_GET);
+OPAL_CALL(opal_secvar_get_next,			OPAL_SECVAR_GET_NEXT);
+OPAL_CALL(opal_secvar_enqueue_update,		OPAL_SECVAR_ENQUEUE_UPDATE);
diff --git a/arch/powerpc/platforms/powernv/opal-secvar.c b/arch/powerpc/platforms/powernv/opal-secvar.c
new file mode 100644
index 000000000000..14133e120bdd
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/opal-secvar.c
@@ -0,0 +1,140 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PowerNV code for secure variables
+ *
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Claudio Carvalho
+ *         Nayna Jain
+ *
+ * APIs to access secure variables managed by OPAL.
+ */
+
+#define pr_fmt(fmt) "secvar: "fmt
+
+#include <linux/types.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
+#include <asm/opal.h>
+#include <asm/secvar.h>
+#include <asm/secure_boot.h>
+
+static int opal_status_to_err(int rc)
+{
+	int err;
+
+	switch (rc) {
+	case OPAL_SUCCESS:
+		err = 0;
+		break;
+	case OPAL_UNSUPPORTED:
+		err = -ENXIO;
+		break;
+	case OPAL_PARAMETER:
+		err = -EINVAL;
+		break;
+	case OPAL_RESOURCE:
+		err = -ENOSPC;
+		break;
+	case OPAL_HARDWARE:
+		err = -EIO;
+		break;
+	case OPAL_NO_MEM:
+		err = -ENOMEM;
+		break;
+	case OPAL_EMPTY:
+		err = -ENOENT;
+		break;
+	case OPAL_PARTIAL:
+		err = -EFBIG;
+		break;
+	default:
+		err = -EINVAL;
+	}
+
+	return err;
+}
+
+static int opal_get_variable(const char *key, uint64_t ksize,
+			     u8 *data, uint64_t *dsize)
+{
+	int rc;
+
+	if (!key || !dsize)
+		return -EINVAL;
+
+	*dsize = cpu_to_be64(*dsize);
+
+	rc = opal_secvar_get(key, ksize, data, dsize);
+
+	*dsize = be64_to_cpu(*dsize);
+
+	return opal_status_to_err(rc);
+}
+
+static int opal_get_next_variable(const char *key, uint64_t *keylen,
+				  uint64_t keybufsize)
+{
+	int rc;
+
+	if (!key || !keylen)
+		return -EINVAL;
+
+	*keylen = cpu_to_be64(*keylen);
+
+	rc = opal_secvar_get_next(key, keylen, keybufsize);
+
+	*keylen = be64_to_cpu(*keylen);
+
+	return opal_status_to_err(rc);
+}
+
+static int opal_set_variable(const char *key, uint64_t ksize, u8 *data,
+			     uint64_t dsize)
+{
+	int rc;
+
+	if (!key || !data)
+		return -EINVAL;
+
+	rc = opal_secvar_enqueue_update(key, ksize, data, dsize);
+
+	return opal_status_to_err(rc);
+}
+
+static const struct secvar_operations opal_secvar_ops = {
+	.get = opal_get_variable,
+	.get_next = opal_get_next_variable,
+	.set = opal_set_variable,
+};
+
+static int opal_secvar_probe(struct platform_device *pdev)
+{
+	if (!opal_check_token(OPAL_SECVAR_GET)
+			|| !opal_check_token(OPAL_SECVAR_GET_NEXT)
+			|| !opal_check_token(OPAL_SECVAR_ENQUEUE_UPDATE)) {
+		pr_err("OPAL doesn't support secure variables\n");
+		return -ENODEV;
+	}
+
+	set_secvar_ops(&opal_secvar_ops);
+
+	return 0;
+}
+
+static const struct of_device_id opal_secvar_match[] = {
+	{ .compatible = "ibm,secvar-backend",},
+	{},
+};
+
+static struct platform_driver opal_secvar_driver = {
+	.driver = {
+		.name = "secvar",
+		.of_match_table = opal_secvar_match,
+	},
+};
+
+static int __init opal_secvar_init(void)
+{
+	return platform_driver_probe(&opal_secvar_driver, opal_secvar_probe);
+}
+device_initcall(opal_secvar_init);
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 38e90270280b..8355bcd00f93 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -1002,6 +1002,9 @@ static int __init opal_init(void)
 	/* Initialise OPAL Power control interface */
 	opal_power_control_init();
 
+	/* Initialize OPAL secure variables */
+	opal_pdev_init("ibm,secvar-backend");
+
 	return 0;
 }
 machine_subsys_initcall(powernv, opal_init);
-- 
2.13.6

[PATCH v9 2/4] powerpc: expose secure variables to userspace via sysfs

[Nayna Jain]

PowerNV secure variables, which store the keys used for OS kernel
verification, are managed by the firmware. These secure variables need to
be accessed by the userspace for addition/deletion of the certificates.

This patch adds the sysfs interface to expose secure variables for PowerNV
secureboot. The users shall use this interface for manipulating
the keys stored in the secure variables.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Eric Richter <erichte@linux.ibm.com>
---
 Documentation/ABI/testing/sysfs-secvar |  46 ++++++
 arch/powerpc/Kconfig                   |  11 ++
 arch/powerpc/kernel/Makefile           |   1 +
 arch/powerpc/kernel/secvar-sysfs.c     | 248 +++++++++++++++++++++++++++++++++
 4 files changed, 306 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-secvar
 create mode 100644 arch/powerpc/kernel/secvar-sysfs.c

diff --git a/Documentation/ABI/testing/sysfs-secvar b/Documentation/ABI/testing/sysfs-secvar
new file mode 100644
index 000000000000..feebb8c57294
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-secvar
@@ -0,0 +1,46 @@
+What:		/sys/firmware/secvar
+Date:		August 2019
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	This directory is created if the POWER firmware supports OS
+		secureboot, thereby secure variables. It exposes interface
+		for reading/writing the secure variables
+
+What:		/sys/firmware/secvar/vars
+Date:		August 2019
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	This directory lists all the secure variables that are supported
+		by the firmware.
+
+What:		/sys/firmware/secvar/format
+Date:		August 2019
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	A string indicating which backend is in use by the firmware.
+		This determines the format of the variable and the accepted
+		format of variable updates.
+
+What:		/sys/firmware/secvar/vars/<variable name>
+Date:		August 2019
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	Each secure variable is represented as a directory named as
+		<variable_name>. The variable name is unique and is in ASCII
+		representation. The data and size can be determined by reading
+		their respective attribute files.
+
+What:		/sys/firmware/secvar/vars/<variable_name>/size
+Date:		August 2019
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	An integer representation of the size of the content of the
+		variable. In other words, it represents the size of the data.
+
+What:		/sys/firmware/secvar/vars/<variable_name>/data
+Date:		August 2019
+Contact:	Nayna Jain h<nayna@linux.ibm.com>
+Description:	A read-only file containing the value of the variable. The size
+		of the file represents the maximum size of the variable data.
+
+What:		/sys/firmware/secvar/vars/<variable_name>/update
+Date:		August 2019
+Contact:	Nayna Jain <nayna@linux.ibm.com>
+Description:	A write-only file that is used to submit the new value for the
+		variable. The size of the file represents the maximum size of
+		the variable data that can be written.
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c795039bdc73..cabc091f3fe1 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -945,6 +945,17 @@ config PPC_SECURE_BOOT
 	  to enable OS secure boot on systems that have firmware support for
 	  it. If in doubt say N.
 
+config PPC_SECVAR_SYSFS
+	bool "Enable sysfs interface for POWER secure variables"
+	default y
+	depends on PPC_SECURE_BOOT
+	depends on SYSFS
+	help
+	  POWER secure variables are managed and controlled by firmware.
+	  These variables are exposed to userspace via sysfs to enable
+	  read/write operations on these variables. Say Y if you have
+	  secure boot enabled and want to expose variables to userspace.
+
 endmenu
 
 config ISA_DMA_API
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 3cf26427334f..b216e9f316ee 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -162,6 +162,7 @@ obj-y				+= ucall.o
 endif
 
 obj-$(CONFIG_PPC_SECURE_BOOT)	+= secure_boot.o ima_arch.o secvar-ops.o
+obj-$(CONFIG_PPC_SECVAR_SYSFS)	+= secvar-sysfs.o
 
 # Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_prom_init.o := n
diff --git a/arch/powerpc/kernel/secvar-sysfs.c b/arch/powerpc/kernel/secvar-sysfs.c
new file mode 100644
index 000000000000..a0a78aba2083
--- /dev/null
+++ b/arch/powerpc/kernel/secvar-sysfs.c
@@ -0,0 +1,248 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 IBM Corporation <nayna@linux.ibm.com>
+ *
+ * This code exposes secure variables to user via sysfs
+ */
+
+#define pr_fmt(fmt) "secvar-sysfs: "fmt
+
+#include <linux/slab.h>
+#include <linux/compat.h>
+#include <linux/string.h>
+#include <linux/of.h>
+#include <asm/secvar.h>
+
+#define NAME_MAX_SIZE	   1024
+
+static struct kobject *secvar_kobj;
+static struct kset *secvar_kset;
+
+static ssize_t format_show(struct kobject *kobj, struct kobj_attribute *attr,
+			   char *buf)
+{
+	ssize_t rc = 0;
+	struct device_node *node;
+	const char *format;
+
+	node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend");
+	if (!of_device_is_available(node))
+		return -ENODEV;
+
+	rc = of_property_read_string(node, "format", &format);
+	if (rc)
+		return rc;
+
+	rc = sprintf(buf, "%s\n", format);
+
+	of_node_put(node);
+
+	return rc;
+}
+
+
+static ssize_t size_show(struct kobject *kobj, struct kobj_attribute *attr,
+			 char *buf)
+{
+	uint64_t dsize;
+	int rc;
+
+	rc = secvar_ops->get(kobj->name, strlen(kobj->name) + 1, NULL, &dsize);
+	if (rc) {
+		pr_err("Error retrieving %s variable size %d\n", kobj->name,
+		       rc);
+		return rc;
+	}
+
+	return sprintf(buf, "%llu\n", dsize);
+}
+
+static ssize_t data_read(struct file *filep, struct kobject *kobj,
+			 struct bin_attribute *attr, char *buf, loff_t off,
+			 size_t count)
+{
+	uint64_t dsize;
+	char *data;
+	int rc;
+
+	rc = secvar_ops->get(kobj->name, strlen(kobj->name) + 1, NULL, &dsize);
+	if (rc) {
+		pr_err("Error getting %s variable size %d\n", kobj->name, rc);
+		return rc;
+	}
+	pr_debug("dsize is %llu\n", dsize);
+
+	data = kzalloc(dsize, GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	rc = secvar_ops->get(kobj->name, strlen(kobj->name) + 1, data, &dsize);
+	if (rc) {
+		pr_err("Error getting %s variable %d\n", kobj->name, rc);
+		goto data_fail;
+	}
+
+	rc = memory_read_from_buffer(buf, count, &off, data, dsize);
+
+data_fail:
+	kfree(data);
+	return rc;
+}
+
+static ssize_t update_write(struct file *filep, struct kobject *kobj,
+			    struct bin_attribute *attr, char *buf, loff_t off,
+			    size_t count)
+{
+	int rc;
+
+	pr_debug("count is %ld\n", count);
+	rc = secvar_ops->set(kobj->name, strlen(kobj->name) + 1, buf, count);
+	if (rc) {
+		pr_err("Error setting the %s variable %d\n", kobj->name, rc);
+		return rc;
+	}
+
+	return count;
+}
+
+static struct kobj_attribute format_attr = __ATTR_RO(format);
+
+static struct kobj_attribute size_attr = __ATTR_RO(size);
+
+static struct bin_attribute data_attr = __BIN_ATTR_RO(data, 0);
+
+static struct bin_attribute update_attr = __BIN_ATTR_WO(update, 0);
+
+static struct bin_attribute *secvar_bin_attrs[] = {
+	&data_attr,
+	&update_attr,
+	NULL,
+};
+
+static struct attribute *secvar_attrs[] = {
+	&size_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group secvar_attr_group = {
+	.attrs = secvar_attrs,
+	.bin_attrs = secvar_bin_attrs,
+};
+__ATTRIBUTE_GROUPS(secvar_attr);
+
+static struct kobj_type secvar_ktype = {
+	.sysfs_ops	= &kobj_sysfs_ops,
+	.default_groups = secvar_attr_groups,
+};
+
+static int update_kobj_size(void)
+{
+
+	struct device_node *node;
+	u64 varsize;
+	int rc = 0;
+
+	node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend");
+	if (!of_device_is_available(node)) {
+		rc = -ENODEV;
+		goto out;
+	}
+
+	rc = of_property_read_u64(node, "max-var-size", &varsize);
+	if (rc)
+		goto out;
+
+	data_attr.size = varsize;
+	update_attr.size = varsize;
+
+out:
+	of_node_put(node);
+
+	return rc;
+}
+
+static int secvar_sysfs_load(void)
+{
+	char *name;
+	uint64_t namesize = 0;
+	struct kobject *kobj;
+	int rc;
+
+	name = kzalloc(NAME_MAX_SIZE, GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+
+	do {
+		rc = secvar_ops->get_next(name, &namesize, NAME_MAX_SIZE);
+		if (rc) {
+			if (rc != -ENOENT)
+				pr_err("error getting secvar from firmware %d\n",
+				       rc);
+			break;
+		}
+
+		kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
+		if (!kobj) {
+			rc = -ENOMEM;
+			break;
+		}
+
+		kobject_init(kobj, &secvar_ktype);
+
+		rc = kobject_add(kobj, &secvar_kset->kobj, "%s", name);
+		if (rc) {
+			pr_warn("kobject_add error %d for attribute: %s\n", rc,
+				name);
+			kobject_put(kobj);
+			kobj = NULL;
+		}
+
+		if (kobj)
+			kobject_uevent(kobj, KOBJ_ADD);
+
+	} while (!rc);
+
+	kfree(name);
+	return rc;
+}
+
+static int secvar_sysfs_init(void)
+{
+	int rc;
+
+	if (!secvar_ops) {
+		pr_warn("secvar: failed to retrieve secvar operations.\n");
+		return -ENODEV;
+	}
+
+	secvar_kobj = kobject_create_and_add("secvar", firmware_kobj);
+	if (!secvar_kobj) {
+		pr_err("secvar: Failed to create firmware kobj\n");
+		return -ENOMEM;
+	}
+
+	rc = sysfs_create_file(secvar_kobj, &format_attr.attr);
+	if (rc) {
+		kobject_put(secvar_kobj);
+		return -ENOMEM;
+	}
+
+	secvar_kset = kset_create_and_add("vars", NULL, secvar_kobj);
+	if (!secvar_kset) {
+		pr_err("secvar: sysfs kobject registration failed.\n");
+		kobject_put(secvar_kobj);
+		return -ENOMEM;
+	}
+
+	rc = update_kobj_size();
+	if (rc) {
+		pr_err("Cannot read the size of the attribute\n");
+		return rc;
+	}
+
+	secvar_sysfs_load();
+
+	return 0;
+}
+
+late_initcall(secvar_sysfs_init);
-- 
2.13.6

[PATCH v9 3/4] x86/efi: move common keyring handler functions to new file

[Nayna Jain]

The handlers to add the keys to the .platform keyring and blacklisted
hashes to the .blacklist keyring is common for both the uefi and powerpc
mechanisms of loading the keys/hashes from the firmware.

This patch moves the common code from load_uefi.c to keyring_handler.c

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Eric Richter <erichte@linux.ibm.com>
---
 security/integrity/Makefile                        |  3 +-
 .../integrity/platform_certs/keyring_handler.c     | 80 ++++++++++++++++++++++
 .../integrity/platform_certs/keyring_handler.h     | 32 +++++++++
 security/integrity/platform_certs/load_uefi.c      | 67 +-----------------
 4 files changed, 115 insertions(+), 67 deletions(-)
 create mode 100644 security/integrity/platform_certs/keyring_handler.c
 create mode 100644 security/integrity/platform_certs/keyring_handler.h

diff --git a/security/integrity/Makefile b/security/integrity/Makefile
index 35e6ca773734..351c9662994b 100644
--- a/security/integrity/Makefile
+++ b/security/integrity/Makefile
@@ -11,7 +11,8 @@ integrity-$(CONFIG_INTEGRITY_SIGNATURE) += digsig.o
 integrity-$(CONFIG_INTEGRITY_ASYMMETRIC_KEYS) += digsig_asymmetric.o
 integrity-$(CONFIG_INTEGRITY_PLATFORM_KEYRING) += platform_certs/platform_keyring.o
 integrity-$(CONFIG_LOAD_UEFI_KEYS) += platform_certs/efi_parser.o \
-					platform_certs/load_uefi.o
+				      platform_certs/load_uefi.o \
+				      platform_certs/keyring_handler.o
 integrity-$(CONFIG_LOAD_IPL_KEYS) += platform_certs/load_ipl_s390.o
 
 obj-$(CONFIG_IMA)			+= ima/
diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c
new file mode 100644
index 000000000000..c5ba695c10e3
--- /dev/null
+++ b/security/integrity/platform_certs/keyring_handler.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <linux/efi.h>
+#include <linux/slab.h>
+#include <keys/asymmetric-type.h>
+#include <keys/system_keyring.h>
+#include "../integrity.h"
+
+static efi_guid_t efi_cert_x509_guid __initdata = EFI_CERT_X509_GUID;
+static efi_guid_t efi_cert_x509_sha256_guid __initdata =
+	EFI_CERT_X509_SHA256_GUID;
+static efi_guid_t efi_cert_sha256_guid __initdata = EFI_CERT_SHA256_GUID;
+
+/*
+ * Blacklist a hash.
+ */
+static __init void uefi_blacklist_hash(const char *source, const void *data,
+				       size_t len, const char *type,
+				       size_t type_len)
+{
+	char *hash, *p;
+
+	hash = kmalloc(type_len + len * 2 + 1, GFP_KERNEL);
+	if (!hash)
+		return;
+	p = memcpy(hash, type, type_len);
+	p += type_len;
+	bin2hex(p, data, len);
+	p += len * 2;
+	*p = 0;
+
+	mark_hash_blacklisted(hash);
+	kfree(hash);
+}
+
+/*
+ * Blacklist an X509 TBS hash.
+ */
+static __init void uefi_blacklist_x509_tbs(const char *source,
+					   const void *data, size_t len)
+{
+	uefi_blacklist_hash(source, data, len, "tbs:", 4);
+}
+
+/*
+ * Blacklist the hash of an executable.
+ */
+static __init void uefi_blacklist_binary(const char *source,
+					 const void *data, size_t len)
+{
+	uefi_blacklist_hash(source, data, len, "bin:", 4);
+}
+
+/*
+ * Return the appropriate handler for particular signature list types found in
+ * the UEFI db and MokListRT tables.
+ */
+__init efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type)
+{
+	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
+		return add_to_platform_keyring;
+	return 0;
+}
+
+/*
+ * Return the appropriate handler for particular signature list types found in
+ * the UEFI dbx and MokListXRT tables.
+ */
+__init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type)
+{
+	if (efi_guidcmp(*sig_type, efi_cert_x509_sha256_guid) == 0)
+		return uefi_blacklist_x509_tbs;
+	if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0)
+		return uefi_blacklist_binary;
+	return 0;
+}
diff --git a/security/integrity/platform_certs/keyring_handler.h b/security/integrity/platform_certs/keyring_handler.h
new file mode 100644
index 000000000000..2462bfa08fe3
--- /dev/null
+++ b/security/integrity/platform_certs/keyring_handler.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef PLATFORM_CERTS_INTERNAL_H
+#define PLATFORM_CERTS_INTERNAL_H
+
+#include <linux/efi.h>
+
+void blacklist_hash(const char *source, const void *data,
+		    size_t len, const char *type,
+		    size_t type_len);
+
+/*
+ * Blacklist an X509 TBS hash.
+ */
+void blacklist_x509_tbs(const char *source, const void *data, size_t len);
+
+/*
+ * Blacklist the hash of an executable.
+ */
+void blacklist_binary(const char *source, const void *data, size_t len);
+
+/*
+ * Return the handler for particular signature list types found in the db.
+ */
+efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type);
+
+/*
+ * Return the handler for particular signature list types found in the dbx.
+ */
+efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type);
+
+#endif
diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c
index 81b19c52832b..4369204a19cd 100644
--- a/security/integrity/platform_certs/load_uefi.c
+++ b/security/integrity/platform_certs/load_uefi.c
@@ -9,6 +9,7 @@
 #include <keys/asymmetric-type.h>
 #include <keys/system_keyring.h>
 #include "../integrity.h"
+#include "keyring_handler.h"
 
 static efi_guid_t efi_cert_x509_guid __initdata = EFI_CERT_X509_GUID;
 static efi_guid_t efi_cert_x509_sha256_guid __initdata =
@@ -68,72 +69,6 @@ static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
 }
 
 /*
- * Blacklist a hash.
- */
-static __init void uefi_blacklist_hash(const char *source, const void *data,
-				       size_t len, const char *type,
-				       size_t type_len)
-{
-	char *hash, *p;
-
-	hash = kmalloc(type_len + len * 2 + 1, GFP_KERNEL);
-	if (!hash)
-		return;
-	p = memcpy(hash, type, type_len);
-	p += type_len;
-	bin2hex(p, data, len);
-	p += len * 2;
-	*p = 0;
-
-	mark_hash_blacklisted(hash);
-	kfree(hash);
-}
-
-/*
- * Blacklist an X509 TBS hash.
- */
-static __init void uefi_blacklist_x509_tbs(const char *source,
-					   const void *data, size_t len)
-{
-	uefi_blacklist_hash(source, data, len, "tbs:", 4);
-}
-
-/*
- * Blacklist the hash of an executable.
- */
-static __init void uefi_blacklist_binary(const char *source,
-					 const void *data, size_t len)
-{
-	uefi_blacklist_hash(source, data, len, "bin:", 4);
-}
-
-/*
- * Return the appropriate handler for particular signature list types found in
- * the UEFI db and MokListRT tables.
- */
-static __init efi_element_handler_t get_handler_for_db(const efi_guid_t *
-						       sig_type)
-{
-	if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0)
-		return add_to_platform_keyring;
-	return 0;
-}
-
-/*
- * Return the appropriate handler for particular signature list types found in
- * the UEFI dbx and MokListXRT tables.
- */
-static __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *
-							sig_type)
-{
-	if (efi_guidcmp(*sig_type, efi_cert_x509_sha256_guid) == 0)
-		return uefi_blacklist_x509_tbs;
-	if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0)
-		return uefi_blacklist_binary;
-	return 0;
-}
-
-/*
  * Load the certs contained in the UEFI databases into the platform trusted
  * keyring and the UEFI blacklisted X.509 cert SHA256 hashes into the blacklist
  * keyring.
-- 
2.13.6

[PATCH v9 4/4] powerpc: load firmware trusted keys/hashes into kernel keyring

[Nayna Jain]

The keys used to verify the Host OS kernel are managed by firmware as
secure variables. This patch loads the verification keys into the .platform
keyring and revocation hashes into .blacklist keyring. This enables
verification and loading of the kernels signed by the boot time keys which
are trusted by firmware.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Eric Richter <erichte@linux.ibm.com>
---
 security/integrity/Kconfig                       |  9 +++
 security/integrity/Makefile                      |  4 +-
 security/integrity/platform_certs/load_powerpc.c | 99 ++++++++++++++++++++++++
 3 files changed, 111 insertions(+), 1 deletion(-)
 create mode 100644 security/integrity/platform_certs/load_powerpc.c

diff --git a/security/integrity/Kconfig b/security/integrity/Kconfig
index 0bae6adb63a9..71f0177e8716 100644
--- a/security/integrity/Kconfig
+++ b/security/integrity/Kconfig
@@ -72,6 +72,15 @@ config LOAD_IPL_KEYS
        depends on S390
        def_bool y
 
+config LOAD_PPC_KEYS
+	bool "Enable loading of platform and blacklisted keys for POWER"
+	depends on INTEGRITY_PLATFORM_KEYRING
+	depends on PPC_SECURE_BOOT
+	default y
+	help
+	  Enable loading of keys to the .platform keyring and blacklisted
+	  hashes to the .blacklist keyring for powerpc based platforms.
+
 config INTEGRITY_AUDIT
 	bool "Enables integrity auditing support "
 	depends on AUDIT
diff --git a/security/integrity/Makefile b/security/integrity/Makefile
index 351c9662994b..7ee39d66cf16 100644
--- a/security/integrity/Makefile
+++ b/security/integrity/Makefile
@@ -14,6 +14,8 @@ integrity-$(CONFIG_LOAD_UEFI_KEYS) += platform_certs/efi_parser.o \
 				      platform_certs/load_uefi.o \
 				      platform_certs/keyring_handler.o
 integrity-$(CONFIG_LOAD_IPL_KEYS) += platform_certs/load_ipl_s390.o
-
+integrity-$(CONFIG_LOAD_PPC_KEYS) += platform_certs/efi_parser.o \
+                                     platform_certs/load_powerpc.o \
+                                     platform_certs/keyring_handler.o
 obj-$(CONFIG_IMA)			+= ima/
 obj-$(CONFIG_EVM)			+= evm/
diff --git a/security/integrity/platform_certs/load_powerpc.c b/security/integrity/platform_certs/load_powerpc.c
new file mode 100644
index 000000000000..9b2596e838ac
--- /dev/null
+++ b/security/integrity/platform_certs/load_powerpc.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 IBM Corporation
+ * Author: Nayna Jain
+ *
+ *      - loads keys and hashes stored and controlled by the firmware.
+ */
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <asm/secure_boot.h>
+#include <asm/secvar.h>
+#include "keyring_handler.h"
+
+/*
+ * Get a certificate list blob from the named secure variable.
+ */
+static __init void *get_cert_list(u8 *key, unsigned long keylen, uint64_t *size)
+{
+	int rc;
+	void *db;
+
+	rc = secvar_ops->get(key, keylen, NULL, size);
+	if (rc) {
+		pr_err("Couldn't get size: %d\n", rc);
+		return NULL;
+	}
+
+	db = kmalloc(*size, GFP_KERNEL);
+	if (!db)
+		return NULL;
+
+	rc = secvar_ops->get(key, keylen, db, size);
+	if (rc) {
+		kfree(db);
+		pr_err("Error reading %s var: %d\n", key, rc);
+		return NULL;
+	}
+
+	return db;
+}
+
+/*
+ * Load the certs contained in the keys databases into the platform trusted
+ * keyring and the blacklisted X.509 cert SHA256 hashes into the blacklist
+ * keyring.
+ */
+static int __init load_powerpc_certs(void)
+{
+	void *db = NULL, *dbx = NULL;
+	uint64_t dbsize = 0, dbxsize = 0;
+	int rc = 0;
+	struct device_node *node;
+
+	if (!secvar_ops)
+		return -ENODEV;
+
+	/* The following only applies for the edk2-compat backend.
+	 * Return early if it is not set.
+	 */
+
+	node = of_find_compatible_node(NULL, NULL, "ibm,secvar-backend");
+	rc = of_property_match_string(node, "format", "ibm,edk2-compat-v1");
+	if (rc)
+		return -ENODEV;
+
+	/* Get db, and dbx.  They might not exist, so it isn't
+	 * an error if we can't get them.
+	 */
+	db = get_cert_list("db", 3, &dbsize);
+	if (!db) {
+		pr_err("Couldn't get db list from firmware\n");
+	} else {
+		rc = parse_efi_signature_list("powerpc:db", db, dbsize,
+					      get_handler_for_db);
+		if (rc)
+			pr_err("Couldn't parse db signatures: %d\n", rc);
+		kfree(db);
+	}
+
+	dbx = get_cert_list("dbx", 4,  &dbxsize);
+	if (!dbx) {
+		pr_info("Couldn't get dbx list from firmware\n");
+	} else {
+		rc = parse_efi_signature_list("powerpc:dbx", dbx, dbxsize,
+					      get_handler_for_dbx);
+		if (rc)
+			pr_err("Couldn't parse dbx signatures: %d\n", rc);
+		kfree(dbx);
+	}
+
+	of_node_put(node);
+
+	return rc;
+}
+late_initcall(load_powerpc_certs);
-- 
2.13.6

Re: [PATCH v9 0/4] powerpc: expose secure variables to the kernel and userspace

[Lakshmi Ramasubramanian]

On 11/10/19 7:10 PM, Nayna Jain wrote:

Hi Nayna,

> In order to verify the OS kernel on PowerNV systems, secure boot requires
> X.509 certificates trusted by the platform. These are stored in secure
> variables controlled by OPAL, called OPAL secure variables. In order to
> enable users to manage the keys, the secure variables need to be exposed
> to userspace.
Are you planning to split the patches in this patch set into smaller 
chunks so that it is easier to code review and also perhaps make it 
easier when merging the changes?

Just a suggestion - but if, folks familiar with this code base don't 
have any objections, please feel free to ignore my comment.

Patch #1
  1, opal-api.h which adds the #defines  OPAL_SECVAR_ and the API signature.
  2, secvar.h then adds secvar_operations struct
  3, powerpc/kernel for the Interface definitions
  4, powernv/opal-secvar.c for the API implementations
  5, powernv/opal-call.c for the API calls
  6, powernv/opal.c for the secvar init calls.

Patch #2
1, Definitions of attribute functions like backend_show, size_show, etc.
2, secvar_sysfs_load
3, secvar_sysfs_init
4, secvar_sysfs_exit

thanks,
  -lakshmi

Re: [PATCH v9 0/4] powerpc: expose secure variables to the kernel and userspace

[Michael Ellerman]

Lakshmi Ramasubramanian <nramas@linux.microsoft.com> writes:
> On 11/10/19 7:10 PM, Nayna Jain wrote:
>
> Hi Nayna,
>
>> In order to verify the OS kernel on PowerNV systems, secure boot requires
>> X.509 certificates trusted by the platform. These are stored in secure
>> variables controlled by OPAL, called OPAL secure variables. In order to
>> enable users to manage the keys, the secure variables need to be exposed
>> to userspace.
> Are you planning to split the patches in this patch set into smaller 
> chunks so that it is easier to code review and also perhaps make it 
> easier when merging the changes?

I don't think splitting them would add any value. They're already split
into the firmware specific bits (patch 1), and the sysfs parts (patch
2), which is sufficient for me.

cheers

Re: [PATCH v9 1/4] powerpc/powernv: Add OPAL API interface to access secure variable

[Michael Ellerman]

On Mon, 2019-11-11 at 03:10:33 UTC, Nayna Jain wrote:
> The X.509 certificates trusted by the platform and required to secure boot
> the OS kernel are wrapped in secure variables, which are controlled by
> OPAL.
> 
> This patch adds firmware/kernel interface to read and write OPAL secure
> variables based on the unique key.
> 
> This support can be enabled using CONFIG_OPAL_SECVAR.
> 
> Signed-off-by: Claudio Carvalho <cclaudio@linux.ibm.com>
> Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
> Signed-off-by: Eric Richter <erichte@linux.ibm.com>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/9155e2341aa8b5df057dc1c77633b33d1a4f17d2

cheers