[PATCH v5 2/3] powerpc/pseries: PLPKS SED Opal keystore support

[gjoyce@linux.vnet.ibm.com]

From: Greg Joyce <gjoyce@linux.vnet.ibm.com>

Define operations for SED Opal to read/write keys
from POWER LPAR Platform KeyStore(PLPKS). This allows
for non-volatile storage of SED Opal keys.

Signed-off-by: Greg Joyce <gjoyce@linux.vnet.ibm.com>
Reviewed-by: Jonathan Derrick <jonathan.derrick@linux.dev>
---
 arch/powerpc/platforms/pseries/Makefile       |   1 +
 .../powerpc/platforms/pseries/plpks_sed_ops.c | 129 ++++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100644 arch/powerpc/platforms/pseries/plpks_sed_ops.c

diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index 92310202bdd7..5bedc06ee2cc 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_PPC_SPLPAR)	+= vphn.o
 obj-$(CONFIG_PPC_SVM)		+= svm.o
 obj-$(CONFIG_FA_DUMP)		+= rtas-fadump.o
 obj-$(CONFIG_PSERIES_PLPKS) += plpks.o
+obj-$(CONFIG_PSERIES_PLPKS) += plpks_sed_ops.o
 
 obj-$(CONFIG_SUSPEND)		+= suspend.o
 obj-$(CONFIG_PPC_VAS)		+= vas.o vas-sysfs.o
diff --git a/arch/powerpc/platforms/pseries/plpks_sed_ops.c b/arch/powerpc/platforms/pseries/plpks_sed_ops.c
new file mode 100644
index 000000000000..cd1084d07716
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/plpks_sed_ops.c
@@ -0,0 +1,129 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * POWER Platform specific code for non-volatile SED key access
+ * Copyright (C) 2022 IBM Corporation
+ *
+ * Define operations for SED Opal to read/write keys
+ * from POWER LPAR Platform KeyStore(PLPKS).
+ *
+ * Self Encrypting Drives(SED) key storage using PLPKS
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/ioctl.h>
+#include <linux/sed-opal-key.h>
+#include "plpks.h"
+
+/*
+ * structure that contains all SED data
+ */
+struct plpks_sed_object_data {
+	u_char version;
+	u_char pad1[7];
+	u_long authority;
+	u_long range;
+	u_int  key_len;
+	u_char key[32];
+};
+
+#define PLPKS_PLATVAR_POLICY            WORLDREADABLE
+#define PLPKS_PLATVAR_OS_COMMON         4
+
+#define PLPKS_SED_OBJECT_DATA_V0        0
+#define PLPKS_SED_MANGLED_LABEL         "/default/pri"
+#define PLPKS_SED_COMPONENT             "sed-opal"
+#define PLPKS_SED_KEY                   "opal-boot-pin"
+
+/*
+ * authority is admin1 and range is global
+ */
+#define PLPKS_SED_AUTHORITY  0x0000000900010001
+#define PLPKS_SED_RANGE      0x0000080200000001
+
+void plpks_init_var(struct plpks_var *var, char *keyname)
+{
+	var->name = keyname;
+	var->namelen = strlen(keyname);
+	if (strcmp(PLPKS_SED_KEY, keyname) == 0) {
+		var->name = PLPKS_SED_MANGLED_LABEL;
+		var->namelen = strlen(keyname);
+	}
+	var->policy = PLPKS_PLATVAR_POLICY;
+	var->os = PLPKS_PLATVAR_OS_COMMON;
+	var->data = NULL;
+	var->datalen = 0;
+	var->component = PLPKS_SED_COMPONENT;
+}
+
+/*
+ * Read the SED Opal key from PLPKS given the label
+ */
+int sed_read_key(char *keyname, char *key, u_int *keylen)
+{
+	struct plpks_var var;
+	struct plpks_sed_object_data *data;
+	u_int offset;
+	int ret;
+	u_int len;
+
+	plpks_init_var(&var, keyname);
+
+	ret = plpks_read_os_var(&var);
+	if (ret != 0)
+		return ret;
+
+	offset = offsetof(struct plpks_sed_object_data, key);
+	if (offset > var.datalen) {
+		kfree(var.data);
+		return -EINVAL;
+	}
+
+	data = (struct plpks_sed_object_data *)var.data;
+	len = min(be32_to_cpu(data->key_len), *keylen);
+
+	if (var.data) {
+		memcpy(key, data->key, len);
+		kfree(var.data);
+	} else
+		len = 0;
+
+	key[len] = '\0';
+	*keylen = len;
+
+	return 0;
+}
+
+/*
+ * Write the SED Opal key to PLPKS given the label
+ */
+int sed_write_key(char *keyname, char *key, u_int keylen)
+{
+	struct plpks_var var;
+	struct plpks_sed_object_data data;
+	struct plpks_var_name vname;
+
+	plpks_init_var(&var, keyname);
+
+	var.datalen = sizeof(struct plpks_sed_object_data);
+	var.data = (u8 *)&data;
+
+	/* initialize SED object */
+	data.version = PLPKS_SED_OBJECT_DATA_V0;
+	data.authority = cpu_to_be64(PLPKS_SED_AUTHORITY);
+	data.range = cpu_to_be64(PLPKS_SED_RANGE);
+	memset(&data.pad1, '\0', sizeof(data.pad1));
+	data.key_len = cpu_to_be32(keylen);
+	memcpy(data.key, (char *)key, keylen);
+
+	/*
+	 * Key update requires remove first. The return value
+	 * is ignored since it's okay if the key doesn't exist.
+	 */
+	vname.namelen = var.namelen;
+	vname.name = var.name;
+	plpks_remove_var(var.component, var.os, vname);
+
+	return plpks_write_var(var);
+}
-- 
gjoyce@linux.vnet.ibm.com