// SPDX-License-Identifier: GPL-2.0-only
/*
* POWER LPAR Platform KeyStore(PLPKS)
* Copyright (C) 2022 IBM Corporation
* Author: Nayna Jain <[email protected]>
*
* Provides access to variables stored in Power LPAR Platform KeyStore(PLPKS).
*/
#define pr_fmt(fmt) "plpks: " fmt
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/of_fdt.h>
#include <linux/libfdt.h>
#include <linux/memblock.h>
#include <asm/hvcall.h>
#include <asm/machdep.h>
#include <asm/plpks.h>
#include <asm/firmware.h>
static u8 *ospassword;
static u16 ospasswordlength;
// Retrieved with H_PKS_GET_CONFIG
static u8 version;
static u16 objoverhead;
static u16 maxpwsize;
static u16 maxobjsize;
static s16 maxobjlabelsize;
static u32 totalsize;
static u32 usedspace;
static u32 supportedpolicies;
static u32 maxlargeobjectsize;
static u64 signedupdatealgorithms;
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[PLPKS_MAX_NAME_SIZE];
size_t 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_PARAMETER:
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:
case H_LONG_BUSY_ORDER_1_MSEC:
case H_LONG_BUSY_ORDER_10_MSEC:
case H_LONG_BUSY_ORDER_100_MSEC:
case H_LONG_BUSY_ORDER_1_SEC:
case H_LONG_BUSY_ORDER_10_SEC:
case H_LONG_BUSY_ORDER_100_SEC:
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;
case H_STATE:
err = -EIO;
break;
case H_R_STATE:
err = -EIO;
break;
case H_IN_USE:
err = -EEXIST;
break;
case H_ABORTED:
err = -EIO;
break;
default:
err = -EINVAL;
}
pr_debug("Converted hypervisor code %d to Linux %d\n", rc, err);
return err;
}
static int plpks_gen_password(void)
{
unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
u8 *password, consumer = PLPKS_OS_OWNER;
int rc;
// If we booted from kexec, we could be reusing an existing password already
if (ospassword) {
pr_debug("Password of length %u already in use\n", ospasswordlength);
return 0;
}
// The password must not cross a page boundary, so we align to the next power of 2
password = kzalloc(roundup_pow_of_two(maxpwsize), GFP_KERNEL);
if (!password)
return -ENOMEM;
rc = plpar_hcall(H_PKS_GEN_PASSWORD, retbuf, consumer, 0,
virt_to_phys(password), maxpwsize);
if (!rc) {
ospasswordlength = maxpwsize;
ospassword = kzalloc(maxpwsize, GFP_KERNEL);
if (!ospassword) {
kfree_sensitive(password);
return -ENOMEM;
}
memcpy(ospassword, password, ospasswordlength);
} else {
if (rc == H_IN_USE) {
pr_warn("Password already set - authenticated operations will fail\n");
rc = 0;
} else {
goto out;
}
}
out:
kfree_sensitive(password);
return pseries_status_to_err(rc);
}
static struct plpks_auth *construct_auth(u8 consumer)
{
struct plpks_auth *auth;
if (consumer > PLPKS_OS_OWNER)
return ERR_PTR(-EINVAL);
// The auth structure must not cross a page boundary and must be
// 16 byte aligned. We align to the next largest power of 2
auth = kzalloc(roundup_pow_of_two(struct_size(auth, password, maxpwsize)), GFP_KERNEL);
if (!auth)
return ERR_PTR(-ENOMEM);
auth->version = 1;
auth->consumer = consumer;
if (consumer == PLPKS_FW_OWNER || consumer == PLPKS_BOOTLOADER_OWNER)
return auth;
memcpy(auth->password, ospassword, ospasswordlength);
auth->passwordlength = cpu_to_be16(ospasswordlength);
return auth;
}
/*
* Label is combination of label attributes + name.
* Label attributes are used internally by kernel and not exposed to the user.
*/
static struct label *construct_label(char *component, u8 varos, u8 *name,
u16 namelen)
{
struct label *label;
size_t slen = 0;
if (!name || namelen > PLPKS_MAX_NAME_SIZE)
return ERR_PTR(-EINVAL);
// Support NULL component for signed updates
if (component) {
slen = strlen(component);
if (slen > sizeof(label->attr.prefix))
return ERR_PTR(-EINVAL);
}
// The label structure must not cross a page boundary, so we align to the next power of 2
label = kzalloc(roundup_pow_of_two(sizeof(*label)), GFP_KERNEL);
if (!label)
return ERR_PTR(-ENOMEM);
if (component)
memcpy(&label->attr.prefix, component, slen);
label->attr.version = PLPKS_LABEL_VERSION;
label->attr.os = varos;
label->attr.length = PLPKS_MAX_LABEL_ATTR_SIZE;
memcpy(&label->name, name, namelen);
label->size = sizeof(struct label_attr) + namelen;
return label;
}
static int _plpks_get_config(void)
{
unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
struct config {
u8 version;
u8 flags;
__be16 rsvd0;
__be16 objoverhead;
__be16 maxpwsize;
__be16 maxobjlabelsize;
__be16 maxobjsize;
__be32 totalsize;
__be32 usedspace;
__be32 supportedpolicies;
__be32 maxlargeobjectsize;
__be64 signedupdatealgorithms;
u8 rsvd1[476];
} __packed * config;
size_t size;
int rc = 0;
size = sizeof(*config);
// Config struct must not cross a page boundary. So long as the struct
// size is a power of 2, this should be fine as alignment is guaranteed
config = kzalloc(size, GFP_KERNEL);
if (!config) {
rc = -ENOMEM;
goto err;
}
rc = plpar_hcall(H_PKS_GET_CONFIG, retbuf, virt_to_phys(config), size);
if (rc != H_SUCCESS) {
rc = pseries_status_to_err(rc);
goto err;
}
version = config->version;
objoverhead = be16_to_cpu(config->objoverhead);
maxpwsize = be16_to_cpu(config->maxpwsize);
maxobjsize = be16_to_cpu(config->maxobjsize);
maxobjlabelsize = be16_to_cpu(config->maxobjlabelsize);
totalsize = be32_to_cpu(config->totalsize);
usedspace = be32_to_cpu(config->usedspace);
supportedpolicies = be32_to_cpu(config->supportedpolicies);
maxlargeobjectsize = be32_to_cpu(config->maxlargeobjectsize);
signedupdatealgorithms = be64_to_cpu(config->signedupdatealgorithms);
// Validate that the numbers we get back match the requirements of the spec
if (maxpwsize < 32) {
pr_err("Invalid Max Password Size received from hypervisor (%d < 32)\n", maxpwsize);
rc = -EIO;
goto err;
}
if (maxobjlabelsize < 255) {
pr_err("Invalid Max Object Label Size received from hypervisor (%d < 255)\n",
maxobjlabelsize);
rc = -EIO;
goto err;
}
if (totalsize < 4096) {
pr_err("Invalid Total Size received from hypervisor (%d < 4096)\n", totalsize);
rc = -EIO;
goto err;
}
if (version >= 3 && maxlargeobjectsize >= 65536 && maxobjsize != 0xFFFF) {
pr_err("Invalid Max Object Size (0x%x != 0xFFFF)\n", maxobjsize);
rc = -EIO;
goto err;
}
err:
kfree(config);
return rc;
}
u8 plpks_get_version(void)
{
return version;
}
u16 plpks_get_objoverhead(void)
{
return objoverhead;
}
u16 plpks_get_maxpwsize(void)
{
return maxpwsize;
}
u16 plpks_get_maxobjectsize(void)
{
return maxobjsize;
}
u16 plpks_get_maxobjectlabelsize(void)
{
return maxobjlabelsize;
}
u32 plpks_get_totalsize(void)
{
return totalsize;
}
u32 plpks_get_usedspace(void)
{
// Unlike other config values, usedspace regularly changes as objects
// are updated, so we need to refresh.
int rc = _plpks_get_config();
if (rc) {
pr_err("Couldn't get config, rc: %d\n", rc);
return 0;
}
return usedspace;
}
u32 plpks_get_supportedpolicies(void)
{
return supportedpolicies;
}
u32 plpks_get_maxlargeobjectsize(void)
{
return maxlargeobjectsize;
}
u64 plpks_get_signedupdatealgorithms(void)
{
return signedupdatealgorithms;
}
u16 plpks_get_passwordlen(void)
{
return ospasswordlength;
}
bool plpks_is_available(void)
{
int rc;
if (!firmware_has_feature(FW_FEATURE_PLPKS))
return false;
rc = _plpks_get_config();
if (rc)
return false;
return true;
}
static int plpks_confirm_object_flushed(struct label *label,
struct plpks_auth *auth)
{
unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
bool timed_out = true;
u64 timeout = 0;
u8 status;
int rc;
do {
rc = plpar_hcall(H_PKS_CONFIRM_OBJECT_FLUSHED, retbuf,
virt_to_phys(auth), virt_to_phys(label),
label->size);
status = retbuf[0];
if (rc) {
timed_out = false;
if (rc == H_NOT_FOUND && status == 1)
rc = 0;
break;
}
if (!rc && status == 1) {
timed_out = false;
break;
}
fsleep(PLPKS_FLUSH_SLEEP);
timeout = timeout + PLPKS_FLUSH_SLEEP;
} while (timeout < PLPKS_MAX_TIMEOUT);
if (timed_out)
return -ETIMEDOUT;
return pseries_status_to_err(rc);
}
int plpks_signed_update_var(struct plpks_var *var, u64 flags)
{
unsigned long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
int rc;
struct label *label;
struct plpks_auth *auth;
u64 continuetoken = 0;
u64 timeout = 0;
if (!var->data || var->datalen <= 0 || var->namelen > PLPKS_MAX_NAME_SIZE)
return -EINVAL;
if (!(var->policy & PLPKS_SIGNEDUPDATE))
return -EINVAL;
// Signed updates need the component to be NULL.
if (var->component)
return -EINVAL;
auth = construct_auth(PLPKS_OS_OWNER);
if (IS_ERR(auth))
return PTR_ERR(auth);
label = construct_label(var->component, var->os, var->name, var->namelen);
if (IS_ERR(label)) {
rc = PTR_ERR(label);
goto out;
}
do {
rc = plpar_hcall9(H_PKS_SIGNED_UPDATE, retbuf,
virt_to_phys(auth), virt_to_phys(label),
label->size, var->policy, flags,
virt_to_phys(var->data), var->datalen,
continuetoken);
continuetoken = retbuf[0];
if (pseries_status_to_err(rc) == -EBUSY) {
int delay_us = get_longbusy_msecs(rc) * 1000;
fsleep(delay_us);
timeout += delay_us;
}
rc = pseries_status_to_err(rc);
} while (rc == -EBUSY && timeout < PLPKS_MAX_TIMEOUT);
if (!rc)
rc = plpks_confirm_object_flushed(label, auth);
kfree(label);
out:
kfree(auth);
return rc;
}
int plpks_write_var(struct plpks_var var)
{
unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
struct plpks_auth *auth;
struct label *label;
int rc;
if (!var.component || !var.data || var.datalen <= 0 ||
var.namelen > PLPKS_MAX_NAME_SIZE || var.datalen > PLPKS_MAX_DATA_SIZE)
return -EINVAL;
if (var.policy & PLPKS_SIGNEDUPDATE)
return -EINVAL;
auth = construct_auth(PLPKS_OS_OWNER);
if (IS_ERR(auth))
return PTR_ERR(auth);
label = construct_label(var.component, var.os, var.name, var.namelen);
if (IS_ERR(label)) {
rc = PTR_ERR(label);
goto out;
}
rc = plpar_hcall(H_PKS_WRITE_OBJECT, retbuf, virt_to_phys(auth),
virt_to_phys(label), label->size, var.policy,
virt_to_phys(var.data), var.datalen);
if (!rc)
rc = plpks_confirm_object_flushed(label, auth);
rc = pseries_status_to_err(rc);
kfree(label);
out:
kfree(auth);
return rc;
}
int plpks_remove_var(char *component, u8 varos, struct plpks_var_name vname)
{
unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
struct plpks_auth *auth;
struct label *label;
int rc;
if (vname.namelen > PLPKS_MAX_NAME_SIZE)
return -EINVAL;
auth = construct_auth(PLPKS_OS_OWNER);
if (IS_ERR(auth))
return PTR_ERR(auth);
label = construct_label(component, varos, vname.name, vname.namelen);
if (IS_ERR(label)) {
rc = PTR_ERR(label);
goto out;
}
rc = plpar_hcall(H_PKS_REMOVE_OBJECT, retbuf, virt_to_phys(auth),
virt_to_phys(label), label->size);
if (!rc)
rc = plpks_confirm_object_flushed(label, auth);
rc = pseries_status_to_err(rc);
kfree(label);
out:
kfree(auth);
return rc;
}
static int plpks_read_var(u8 consumer, struct plpks_var *var)
{
unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
struct plpks_auth *auth;
struct label *label = NULL;
u8 *output;
int rc;
if (var->namelen > PLPKS_MAX_NAME_SIZE)
return -EINVAL;
auth = construct_auth(consumer);
if (IS_ERR(auth))
return PTR_ERR(auth);
if (consumer == PLPKS_OS_OWNER) {
label = construct_label(var->component, var->os, var->name,
var->namelen);
if (IS_ERR(label)) {
rc = PTR_ERR(label);
goto out_free_auth;
}
}
output = kzalloc(maxobjsize, GFP_KERNEL);
if (!output) {
rc = -ENOMEM;
goto out_free_label;
}
if (consumer == PLPKS_OS_OWNER)
rc = plpar_hcall(H_PKS_READ_OBJECT, retbuf, virt_to_phys(auth),
virt_to_phys(label), label->size, virt_to_phys(output),
maxobjsize);
else
rc = plpar_hcall(H_PKS_READ_OBJECT, retbuf, virt_to_phys(auth),
virt_to_phys(var->name), var->namelen, virt_to_phys(output),
maxobjsize);
if (rc != H_SUCCESS) {
rc = pseries_status_to_err(rc);
goto out_free_output;
}
if (!var->data || var->datalen > retbuf[0])
var->datalen = retbuf[0];
var->policy = retbuf[1];
if (var->data)
memcpy(var->data, output, var->datalen);
rc = 0;
out_free_output:
kfree(output);
out_free_label:
kfree(label);
out_free_auth:
kfree(auth);
return rc;
}
int plpks_read_os_var(struct plpks_var *var)
{
return plpks_read_var(PLPKS_OS_OWNER, var);
}
int plpks_read_fw_var(struct plpks_var *var)
{
return plpks_read_var(PLPKS_FW_OWNER, var);
}
int plpks_read_bootloader_var(struct plpks_var *var)
{
return plpks_read_var(PLPKS_BOOTLOADER_OWNER, var);
}
int plpks_populate_fdt(void *fdt)
{
int chosen_offset = fdt_path_offset(fdt, "/chosen");
if (chosen_offset < 0) {
pr_err("Can't find chosen node: %s\n",
fdt_strerror(chosen_offset));
return chosen_offset;
}
return fdt_setprop(fdt, chosen_offset, "ibm,plpks-pw", ospassword, ospasswordlength);
}
// Once a password is registered with the hypervisor it cannot be cleared without
// rebooting the LPAR, so to keep using the PLPKS across kexec boots we need to
// recover the previous password from the FDT.
//
// There are a few challenges here. We don't want the password to be visible to
// users, so we need to clear it from the FDT. This has to be done in early boot.
// Clearing it from the FDT would make the FDT's checksum invalid, so we have to
// manually cause the checksum to be recalculated.
void __init plpks_early_init_devtree(void)
{
void *fdt = initial_boot_params;
int chosen_node = fdt_path_offset(fdt, "/chosen");
const u8 *password;
int len;
if (chosen_node < 0)
return;
password = fdt_getprop(fdt, chosen_node, "ibm,plpks-pw", &len);
if (len <= 0) {
pr_debug("Couldn't find ibm,plpks-pw node.\n");
return;
}
ospassword = memblock_alloc_raw(len, SMP_CACHE_BYTES);
if (!ospassword) {
pr_err("Error allocating memory for password.\n");
goto out;
}
memcpy(ospassword, password, len);
ospasswordlength = (u16)len;
out:
fdt_nop_property(fdt, chosen_node, "ibm,plpks-pw");
// Since we've cleared the password, we must update the FDT checksum
early_init_dt_verify(fdt);
}
static __init int pseries_plpks_init(void)
{
int rc;
if (!firmware_has_feature(FW_FEATURE_PLPKS))
return -ENODEV;
rc = _plpks_get_config();
if (rc) {
pr_err("POWER LPAR Platform KeyStore is not supported or enabled\n");
return rc;
}
rc = plpks_gen_password();
if (rc)
pr_err("Failed setting POWER LPAR Platform KeyStore Password\n");
else
pr_info("POWER LPAR Platform KeyStore initialized successfully\n");
return rc;
}
machine_arch_initcall(pseries, pseries_plpks_init);
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