[PATCH 1/2] powerpc/pseries: define driver for Platform KeyStore
Murilo Opsfelder Araújo
muriloo at linux.ibm.com
Thu Jul 21 02:29:36 AEST 2022
Hi, Nayna.
Some comments below.
On 7/12/22 21:59, Nayna Jain wrote:
> PowerVM provides an isolated Platform Keystore(PKS) storage allocation
> for each LPAR with individually managed access controls to store
> sensitive information securely. It provides a new set of hypervisor
> calls for Linux kernel to access PKS storage.
I think it would be nice to have some consistency as to spaces before
acronymous, e.g.: "Keystore(PKS)" vs. "Keystore (PKS)". The same could
be applied to "Keystore" vs. "KeyStore" vs. "Key Storage".
>
> Define PLPKS driver using H_CALL interface to access PKS storage.
>
> Signed-off-by: Nayna Jain <nayna at linux.ibm.com>
> ---
> arch/powerpc/include/asm/hvcall.h | 9 +
> arch/powerpc/include/asm/plpks.h | 90 ++++
> arch/powerpc/platforms/pseries/Kconfig | 13 +
> arch/powerpc/platforms/pseries/Makefile | 2 +
> arch/powerpc/platforms/pseries/plpks/Makefile | 7 +
> arch/powerpc/platforms/pseries/plpks/plpks.c | 509 ++++++++++++++++++
> 6 files changed, 630 insertions(+)
> create mode 100644 arch/powerpc/include/asm/plpks.h
> create mode 100644 arch/powerpc/platforms/pseries/plpks/Makefile
> create mode 100644 arch/powerpc/platforms/pseries/plpks/plpks.c
>
> diff --git a/arch/powerpc/include/asm/hvcall.h b/arch/powerpc/include/asm/hvcall.h
> index d92a20a85395..24b661b0717c 100644
> --- a/arch/powerpc/include/asm/hvcall.h
> +++ b/arch/powerpc/include/asm/hvcall.h
> @@ -97,6 +97,7 @@
> #define H_OP_MODE -73
> #define H_COP_HW -74
> #define H_STATE -75
> +#define H_IN_USE -77
> #define H_UNSUPPORTED_FLAG_START -256
> #define H_UNSUPPORTED_FLAG_END -511
> #define H_MULTI_THREADS_ACTIVE -9005
> @@ -321,6 +322,14 @@
> #define H_SCM_UNBIND_ALL 0x3FC
> #define H_SCM_HEALTH 0x400
> #define H_SCM_PERFORMANCE_STATS 0x418
> +#define H_PKS_GET_CONFIG 0x41C
> +#define H_PKS_SET_PASSWORD 0x420
> +#define H_PKS_GEN_PASSWORD 0x424
> +#define H_PKS_WRITE_OBJECT 0x42C
> +#define H_PKS_GEN_KEY 0x430
> +#define H_PKS_READ_OBJECT 0x434
> +#define H_PKS_REMOVE_OBJECT 0x438
> +#define H_PKS_CONFIRM_OBJECT_FLUSHED 0x43C
> #define H_RPT_INVALIDATE 0x448
> #define H_SCM_FLUSH 0x44C
> #define H_GET_ENERGY_SCALE_INFO 0x450
> diff --git a/arch/powerpc/include/asm/plpks.h b/arch/powerpc/include/asm/plpks.h
> new file mode 100644
> index 000000000000..cf60e53e1f15
> --- /dev/null
> +++ b/arch/powerpc/include/asm/plpks.h
> @@ -0,0 +1,90 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2022 IBM Corporation
> + * Author: Nayna Jain <nayna at linux.ibm.com>
> + *
> + * Platform keystore for pseries LPAR(PLPKS).
> + */
> +
> +#ifndef _PSERIES_PLPKS_H
> +#define _PSERIES_PLPKS_H
> +
> +#include <linux/types.h>
> +#include <linux/list.h>
> +
> +#define OSSECBOOTAUDIT 0x40000000
> +#define OSSECBOOTENFORCE 0x20000000
> +#define WORLDREADABLE 0x08000000
> +#define SIGNEDUPDATE 0x01000000
> +
> +#define PLPKS_VAR_LINUX 0x01
> +#define PLPKS_VAR_COMMON 0x04
> +
> +struct plpks_var {
> + char *component;
> + u8 os;
> + u8 *name;
> + u16 namelen;
> + u32 policy;
> + u16 datalen;
> + u8 *data;
> +};
> +
> +struct plpks_var_name {
> + u16 namelen;
> + u8 *name;
> +};
> +
> +struct plpks_var_name_list {
> + u32 varcount;
> + struct plpks_var_name varlist[];
> +};
> +
> +struct plpks_config {
> + u8 version;
> + u8 flags;
> + u32 rsvd0;
> + u16 maxpwsize;
> + u16 maxobjlabelsize;
> + u16 maxobjsize;
> + u32 totalsize;
> + u32 usedspace;
> + u32 supportedpolicies;
> + u64 rsvd1;
> +} __packed;
> +
> +/**
> + * Successful return from this API implies PKS is available.
> + * This is used to initialize kernel driver and user interfaces.
> + */
> +struct plpks_config *plpks_get_config(void);
> +
> +/**
> + * Writes the specified var and its data to PKS.
> + * Any caller of PKS driver should present a valid component type for
> + * their variable.
> + */
> +int plpks_write_var(struct plpks_var var);
> +
> +/**
> + * Removes the specified var and its data from PKS.
> + */
> +int plpks_remove_var(char *component, u8 varos,
> + struct plpks_var_name vname);
> +
> +/**
> + * Returns the data for the specified os variable.
> + */
> +int plpks_read_os_var(struct plpks_var *var);
> +
> +/**
> + * Returns the data for the specified firmware variable.
> + */
> +int plpks_read_fw_var(struct plpks_var *var);
> +
> +/**
> + * Returns the data for the specified bootloader variable.
> + */
> +int plpks_read_bootloader_var(struct plpks_var *var);
> +
> +#endif
> diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig
> index f7fd91d153a4..de6efe5d18c2 100644
> --- a/arch/powerpc/platforms/pseries/Kconfig
> +++ b/arch/powerpc/platforms/pseries/Kconfig
> @@ -142,6 +142,19 @@ config IBMEBUS
> help
> Bus device driver for GX bus based adapters.
>
> +config PSERIES_PLPKS
> + depends on PPC_PSERIES
> + tristate "Support for the Platform Key Storage"
> + help
> + PowerVM provides an isolated Platform Keystore(PKS) storage
> + allocation for each LPAR with individually managed access
> + controls to store sensitive information securely. It can be
> + used to store asymmetric public keys or secrets as required
> + by different usecases. Select this config to enable
> + operating system interface to hypervisor to access this space.
> +
> + If unsure, select N.
> +
> config PAPR_SCM
> depends on PPC_PSERIES && MEMORY_HOTPLUG && LIBNVDIMM
> tristate "Support for the PAPR Storage Class Memory interface"
> diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
> index 7aaff5323544..d6a9209e08c0 100644
> --- a/arch/powerpc/platforms/pseries/Makefile
> +++ b/arch/powerpc/platforms/pseries/Makefile
> @@ -37,3 +37,5 @@ obj-$(CONFIG_ARCH_HAS_CC_PLATFORM) += cc_platform.o
> # nothing that operates in real mode is safe for KASAN
> KASAN_SANITIZE_ras.o := n
> KASAN_SANITIZE_kexec.o := n
> +
> +obj-$(CONFIG_PSERIES_PLPKS) += plpks/
> diff --git a/arch/powerpc/platforms/pseries/plpks/Makefile b/arch/powerpc/platforms/pseries/plpks/Makefile
> new file mode 100644
> index 000000000000..e651ace920db
> --- /dev/null
> +++ b/arch/powerpc/platforms/pseries/plpks/Makefile
> @@ -0,0 +1,7 @@
> +# SPDX-License-Identifier: GPL-2.0-only
> +#
> +# Copyright (C) 2022 IBM Corporation
> +# Author: Nayna Jain <nayna at linux.ibm.com>
> +#
> +
> +obj-$(CONFIG_PSERIES_PLPKS) += plpks.o
> diff --git a/arch/powerpc/platforms/pseries/plpks/plpks.c b/arch/powerpc/platforms/pseries/plpks/plpks.c
> new file mode 100644
> index 000000000000..463ce93f9066
> --- /dev/null
> +++ b/arch/powerpc/platforms/pseries/plpks/plpks.c
> @@ -0,0 +1,509 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * POWER LPAR Platform KeyStore (PLPKS)
> + * Copyright (C) 2022 IBM Corporation
> + * Author: Nayna Jain <nayna at linux.ibm.com>
> + *
> + * Provides access to variables stored in Power LPAR Platform KeyStore(PLPKS).
> + */
> +
> +#include <linux/module.h>
> +#include <linux/types.h>
> +#include <linux/errno.h>
> +#include <linux/string.h>
> +#include <linux/slab.h>
> +#include <linux/delay.h>
> +#include <asm/hvcall.h>
> +#include <asm/plpks.h>
> +#include <asm/unaligned.h>
> +#include <asm/machdep.h>
> +
> +#define MODULE_VERS "1.0"
> +#define MODULE_NAME "pseries-plpks"
> +
> +#define PKS_FW_OWNER 0x1
> +#define PKS_BOOTLOADER_OWNER 0x2
> +#define PKS_OS_OWNER 0x3
> +
> +#define MAX_LABEL_ATTR_SIZE 16
> +#define MAX_NAME_SIZE 239
> +#define MAX_DATA_SIZE 4000
> +
> +#define PKS_FLUSH_MAX_TIMEOUT 5000 //msec
> +#define PKS_FLUSH_SLEEP 10 //msec
> +#define PKS_FLUSH_SLEEP_RANGE 400
> +
> +static bool configset;
> +static struct plpks_config *config;
> +static u8 *ospassword;
> +static u16 ospasswordlength;
> +
> +struct plpks_auth {
> + u8 version;
> + u8 consumer;
> + __be64 rsvd0;
> + __be32 rsvd1;
> + __be16 passwordlength;
> + u8 password[];
> +} __packed __aligned(16);
> +
> +struct label_attr {
> + u8 prefix[8];
> + u8 version;
> + u8 os;
> + u8 length;
> + u8 reserved[5];
> +};
> +
> +struct label {
> + struct label_attr attr;
> + u8 name[MAX_NAME_SIZE];
> +};
> +
> +static int pseries_status_to_err(int rc)
> +{
> + int err;
> +
> + switch (rc) {
> + case H_SUCCESS:
> + err = 0;
> + break;
> + case H_FUNCTION:
> + err = -ENXIO;
> + break;
> + case H_P2:
> + case H_P3:
> + case H_P4:
> + case H_P5:
> + case H_P6:
> + err = -EINVAL;
> + break;
> + case H_NOT_FOUND:
> + err = -ENOENT;
> + break;
> + case H_BUSY:
> + err = -EBUSY;
> + break;
> + case H_AUTHORITY:
> + err = -EPERM;
> + break;
> + case H_NO_MEM:
> + err = -ENOMEM;
> + break;
> + case H_RESOURCE:
> + err = -EEXIST;
> + break;
> + case H_TOO_BIG:
> + err = -EFBIG;
> + break;
> + default:
> + err = -EINVAL;
> + }
> +
> + return err;
> +}
Shouldn't we handle other platform return codes, e.g.: H_STATE,
H_IN_USE?
> +
> +static int plpks_gen_password(void)
> +{
> + unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = {0};
> + u8 consumer = PKS_OS_OWNER;
> + int rc;
> +
> + ospassword = kzalloc(config->maxpwsize, GFP_KERNEL);
> + if (!ospassword)
> + return -ENOMEM;
> +
> + ospasswordlength = config->maxpwsize;
> + rc = plpar_hcall(H_PKS_GEN_PASSWORD,
> + retbuf,
> + consumer,
> + 0,
> + virt_to_phys(ospassword),
> + config->maxpwsize);
> +
> + return pseries_status_to_err(rc);
> +}
> +
> +static int construct_auth(u8 consumer, struct plpks_auth **auth)
> +{
> + pr_debug("max password size is %u\n", config->maxpwsize);
> +
> + if (!auth || consumer > 3)
> + return -EINVAL;
> +
> + *auth = kmalloc(struct_size(*auth, password, config->maxpwsize),
> + GFP_KERNEL);
> + if (!*auth)
> + return -ENOMEM;
> +
> + (*auth)->version = 1;
> + (*auth)->consumer = consumer;
> + (*auth)->rsvd0 = 0;
> + (*auth)->rsvd1 = 0;
> + if (consumer == PKS_FW_OWNER || consumer == PKS_BOOTLOADER_OWNER) {
> + pr_debug("consumer is bootloader or firmware\n");
> + (*auth)->passwordlength = 0;
> + return 0;
> + }
> +
> + (*auth)->passwordlength = (__force __be16)ospasswordlength;
> +
> + memcpy((*auth)->password, ospassword,
> + flex_array_size(*auth, password,
> + (__force u16)((*auth)->passwordlength)));
> + (*auth)->passwordlength = cpu_to_be16((__force u16)((*auth)->passwordlength));
> +
> + return 0;
> +}
> +
> +/**
> + * Label is combination of label attributes + name.
> + * Label attributes are used internally by kernel and not exposed to the user.
> + */
> +static int construct_label(char *component, u8 varos, u8 *name, u16 namelen, u8 **label)
> +{
> + int varlen;
> + int len = 0;
> + int llen = 0;
> + int i;
> + int rc = 0;
> + u8 labellength = MAX_LABEL_ATTR_SIZE;
> +
> + if (!label)
> + return -EINVAL;
> +
> + varlen = namelen + sizeof(struct label_attr);
> + *label = kzalloc(varlen, GFP_KERNEL);
> +
> + if (!*label)
> + return -ENOMEM;
> +
> + if (component) {
> + len = strlen(component);
> + memcpy(*label, component, len);
> + }
> + llen = len;
> +
> + if (component)
> + len = 8 - strlen(component);
> + else
> + len = 8;
> +
> + memset(*label + llen, 0, len);
> + llen = llen + len;
> +
> + ((*label)[llen]) = 0;
> + llen = llen + 1;
> +
> + memcpy(*label + llen, &varos, 1);
> + llen = llen + 1;
> +
> + memcpy(*label + llen, &labellength, 1);
> + llen = llen + 1;
> +
> + memset(*label + llen, 0, 5);
> + llen = llen + 5;
> +
> + memcpy(*label + llen, name, namelen);
> + llen = llen + namelen;
> +
> + for (i = 0; i < llen; i++)
> + pr_debug("%c", (*label)[i]);
> +
> + rc = llen;
> + return rc;
> +}
> +
> +static int _plpks_get_config(void)
> +{
> + unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = {0};
> + int rc;
> + size_t size = sizeof(struct plpks_config);
> +
> + config = kzalloc(size, GFP_KERNEL);
> + if (!config)
> + return -ENOMEM;
> +
> + rc = plpar_hcall(H_PKS_GET_CONFIG,
> + retbuf,
> + virt_to_phys(config),
> + size);
> +
> + if (rc != H_SUCCESS)
> + return pseries_status_to_err(rc);
> +
> + config->rsvd0 = be32_to_cpu((__force __be32)config->rsvd0);
> + config->maxpwsize = be16_to_cpu((__force __be16)config->maxpwsize);
> + config->maxobjlabelsize = be16_to_cpu((__force __be16)config->maxobjlabelsize);
> + config->maxobjsize = be16_to_cpu((__force __be16)config->maxobjsize);
> + config->totalsize = be32_to_cpu((__force __be32)config->totalsize);
> + config->usedspace = be32_to_cpu((__force __be32)config->usedspace);
> + config->supportedpolicies = be32_to_cpu((__force __be32)config->supportedpolicies);
> + config->rsvd1 = be64_to_cpu((__force __be64)config->rsvd1);
> +
> + configset = true;
> +
> + return 0;
> +}
> +
> +static int plpks_confirm_object_flushed(u8 *label, u16 labellen)
> +{
> + unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = {0};
> + int rc;
> + u64 timeout = 0;
> + struct plpks_auth *auth;
> + u8 status;
> + int i;
> +
> + rc = construct_auth(PKS_OS_OWNER, &auth);
> + if (rc)
> + return rc;
> +
> + for (i = 0; i < labellen; i++)
> + pr_debug("%02x ", label[i]);
> +
> + do {
> + rc = plpar_hcall(H_PKS_CONFIRM_OBJECT_FLUSHED,
> + retbuf,
> + virt_to_phys(auth),
> + virt_to_phys(label),
> + labellen);
> +
> + status = retbuf[0];
> + if (rc) {
> + pr_info("rc is %d, status is %d\n", rc, status);
> + if (rc == H_NOT_FOUND && status == 1)
> + rc = 0;
> + break;
> + }
> +
> + pr_debug("rc is %d, status is %d\n", rc, status);
> +
> + if (!rc && status == 1)
> + break;
> +
> + usleep_range(PKS_FLUSH_SLEEP, PKS_FLUSH_SLEEP + PKS_FLUSH_SLEEP_RANGE);
> + timeout = timeout + PKS_FLUSH_SLEEP;
> + pr_debug("timeout is %llu\n", timeout);
> +
> + } while (timeout < PKS_FLUSH_MAX_TIMEOUT);
> +
> + rc = pseries_status_to_err(rc);
> +
> + kfree(auth);
> +
> + return rc;
> +}
> +
> +int plpks_write_var(struct plpks_var var)
> +{
> + unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = {0};
> + int rc;
> + u8 *label;
> + u16 varlen;
> + u8 *data = var.data;
> + struct plpks_auth *auth;
> +
> + if (!var.component || !data || var.datalen <= 0 ||
> + var.namelen > MAX_NAME_SIZE ||
> + var.datalen > MAX_DATA_SIZE)
> + return -EINVAL;
> +
> + if (var.policy & SIGNEDUPDATE)
> + return -EINVAL;
> +
> + rc = construct_auth(PKS_OS_OWNER, &auth);
> + if (rc)
> + return rc;
> +
> + rc = construct_label(var.component, var.os, var.name, var.namelen,
> + &label);
> + if (rc <= 0)
> + goto out;
> +
> + varlen = rc;
> + pr_debug("Name to be written is of label size %d\n", varlen);
> + rc = plpar_hcall(H_PKS_WRITE_OBJECT,
> + retbuf,
> + virt_to_phys(auth),
> + virt_to_phys(label),
> + varlen,
> + var.policy,
> + virt_to_phys(data),
> + var.datalen);
> +
> + if (!rc)
> + rc = plpks_confirm_object_flushed(label, varlen);
> +
> + rc = pseries_status_to_err(rc);
> + kfree(label);
> +
> +out:
> + kfree(auth);
> +
> + return rc;
> +}
> +EXPORT_SYMBOL(plpks_write_var);
> +
> +int plpks_remove_var(char *component, u8 varos, struct plpks_var_name vname)
> +{
> + unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = {0};
> + int rc;
> + u8 *label;
> + u16 varlen;
> + struct plpks_auth *auth;
> +
> + if (!component || vname.namelen > MAX_NAME_SIZE)
> + return -EINVAL;
> +
> + rc = construct_auth(PKS_OS_OWNER, &auth);
> + if (rc)
> + return rc;
> +
> + rc = construct_label(component, varos, vname.name, vname.namelen, &label);
> + if (rc <= 0)
> + goto out;
> +
> + varlen = rc;
> + pr_debug("Name to be written is of label size %d\n", varlen);
> + rc = plpar_hcall(H_PKS_REMOVE_OBJECT,
> + retbuf,
> + virt_to_phys(auth),
> + virt_to_phys(label),
> + varlen);
> +
> + if (!rc)
> + rc = plpks_confirm_object_flushed(label, varlen);
> +
> + rc = pseries_status_to_err(rc);
> + kfree(label);
> +
> +out:
> + kfree(auth);
> +
> + return rc;
> +}
> +EXPORT_SYMBOL(plpks_remove_var);
> +
> +static int plpks_read_var(u8 consumer, struct plpks_var *var)
> +{
> + unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = {0};
> + int rc;
> + u16 outlen = config->maxobjsize;
> + u8 *label;
> + u8 *out;
> + u16 varlen;
> + struct plpks_auth *auth;
> +
> + if (var->namelen > MAX_NAME_SIZE)
> + return -EINVAL;
> +
> + rc = construct_auth(PKS_OS_OWNER, &auth);
> + if (rc)
> + return rc;
> +
> + rc = construct_label(var->component, var->os, var->name, var->namelen,
> + &label);
> + if (rc <= 0)
> + goto out;
> +
> + varlen = rc;
> + pr_debug("Name to be written is of label size %d\n", varlen);
> + out = kzalloc(outlen, GFP_KERNEL);
> + if (!out)
> + goto out1;
> +
> + rc = plpar_hcall(H_PKS_READ_OBJECT,
> + retbuf,
> + virt_to_phys(auth),
> + virt_to_phys(label),
> + varlen,
> + virt_to_phys(out),
> + outlen);
> +
> + if (rc != H_SUCCESS) {
> + pr_err("Failed to read %d\n", rc);
> + rc = pseries_status_to_err(rc);
> + goto out2;
> + }
> +
> + if (var->datalen == 0 || var->datalen > retbuf[0])
> + var->datalen = retbuf[0];
> +
> + var->data = kzalloc(var->datalen, GFP_KERNEL);
> + if (!var->data) {
> + rc = -ENOMEM;
> + goto out2;
> + }
> + var->policy = retbuf[1];
> +
> + memcpy(var->data, out, var->datalen);
> +
> +out2:
> + kfree(out);
> +
> +out1:
> + kfree(label);
> +
> +out:
> + kfree(auth);
> +
> + return rc;
> +}
> +
> +int plpks_read_os_var(struct plpks_var *var)
> +{
> + return plpks_read_var(PKS_OS_OWNER, var);
> +}
> +EXPORT_SYMBOL(plpks_read_os_var);
> +
> +int plpks_read_fw_var(struct plpks_var *var)
> +{
> + return plpks_read_var(PKS_FW_OWNER, var);
> +}
> +EXPORT_SYMBOL(plpks_read_fw_var);
> +
> +int plpks_read_bootloader_var(struct plpks_var *var)
> +{
> + return plpks_read_var(PKS_BOOTLOADER_OWNER, var);
> +}
> +EXPORT_SYMBOL(plpks_read_bootloader_var);
> +
> +struct plpks_config *plpks_get_config(void)
> +{
> + if (!configset) {
> + if (_plpks_get_config())
> + return NULL;
> + }
> +
> + return config;
> +}
> +EXPORT_SYMBOL(plpks_get_config);
> +
> +static __init int pseries_plpks_init(void)
> +{
> + int rc = 0;
> +
> + rc = _plpks_get_config();
> +
> + if (rc) {
> + pr_err("Error initializing plpks\n");
> + return rc;
> + }
> +
> + rc = plpks_gen_password();
> + if (rc) {
> + if (rc == H_IN_USE) {
The rc value will never be H_IN_USE here because
pseries_status_to_err() is called within plpks_gen_password() before
returning and the plpar_hcall() return code is not propagated. You
will get -EINVAL here if plpar_hcall() returned H_IN_USE.
I think we could enhance the error handling to print messages like
"PKS not supported", "PKS access blocked due to partition state", and
"PKS password already in use". I bet these messages will help
troubleshooting issues.
> + rc = 0;
> + } else {
> + pr_err("Failed setting password %d\n", rc);
> + rc = pseries_status_to_err(rc);
Here, pseries_status_to_err() is called again (it was already called
within plpks_gen_password()). After calling it twice, the rc will
always be -EINVAL here, won't it?
> + return rc;
> + }
> + }
> +
> + pr_info("POWER LPAR Platform Keystore initialized successfully\n");
> +
> + return rc;
> +}
> +arch_initcall(pseries_plpks_init);
--
Murilo
--
Murilo
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