plpks.c

// 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

#define PLPKS_WRAPKEY_COMPONENT	"PLPKSWR"
#define PLPKS_WRAPKEY_NAME	"default-wrapping-key"

/*
 * To 4K align the {input, output} buffers to the {UN}WRAP H_CALLs
 */
#define PLPKS_WRAPPING_BUF_ALIGN	4096

/*
 * To ensure the output buffer's length is at least 1024 bytes greater
 * than the input buffer's length during the WRAP H_CALL
 */
#define PLPKS_WRAPPING_BUF_DIFF	1024

#define PLPKS_WRAP_INTERFACE_BIT	3
#define PLPKS_WRAPPING_KEY_LENGTH	32

#define WRAPFLAG_BE_BIT_SET(be_bit) \
	BIT_ULL(63 - (be_bit))

#define WRAPFLAG_BE_GENMASK(be_bit_hi, be_bit_lo) \
	GENMASK_ULL(63 - (be_bit_hi), 63 - (be_bit_lo))

#define WRAPFLAG_BE_FIELD_PREP(be_bit_hi, be_bit_lo, val) \
	FIELD_PREP(WRAPFLAG_BE_GENMASK(be_bit_hi, be_bit_lo), (val))

#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 <linux/bitfield.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;
static u64 wrappingfeatures;
static bool wrapsupport;

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;
		__be64 wrappingfeatures;
		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);
	wrappingfeatures = be64_to_cpu(config->wrappingfeatures);
	wrapsupport = config->flags & PPC_BIT8(PLPKS_WRAP_INTERFACE_BIT);

	// 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;
}

/**
 * plpks_get_version() - Get the version of the PLPKS config structure.
 *
 * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
 * reads the PLPKS config structure version and saves it in a file local static
 * version variable.
 *
 * Returns: On success the saved PLPKS config structure version is returned, 0
 * if not.
 */
u8 plpks_get_version(void)
{
	return version;
}

/**
 * plpks_get_objoverhead() - Get the hypervisor storage overhead per object.
 *
 * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
 * reads the per object hypervisor storage overhead in bytes into the local
 * static objoverhead variable, excluding the size of the object or the label.
 * This value can be treated as valid only when the PLPKS config structure
 * version >= 2.
 *
 * Returns: If PLPKS config structure version >= 2 then the storage overhead is
 * returned, 0 otherwise.
 */
u16 plpks_get_objoverhead(void)
{
	return objoverhead;
}

/**
 * plpks_get_maxpwsize() - Get the maximum password size.
 *
 * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
 * reads the maximum password size and checks if it is 32 bytes at the least
 * before storing it in the local static maxpwsize variable.
 *
 * Returns: On success the maximum password size is returned, 0 if not.
 */
u16 plpks_get_maxpwsize(void)
{
	return maxpwsize;
}

/**
 * plpks_get_maxobjectsize() - Get the maximum object size supported by the
 * PLPKS.
 *
 * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
 * reads the maximum object size into the file local static maxobjsize variable.
 *
 * Returns: On success the maximum object size is returned, 0 if not.
 */
u16 plpks_get_maxobjectsize(void)
{
	return maxobjsize;
}

/**
 * plpks_get_maxobjectlabelsize() - Get the maximum object label size supported
 * by the PLPKS.
 *
 * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
 * reads the maximum object label size into the local static maxobjlabelsize
 * variable.
 *
 * Returns: On success the maximum object label size is returned, 0 if not.
 */
u16 plpks_get_maxobjectlabelsize(void)
{
	return maxobjlabelsize;
}

/**
 * plpks_get_totalsize() - Get the total size of the PLPKS that is configured.
 *
 * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
 * reads the total size of the PLPKS that is configured for the LPAR into the
 * file local static totalsize variable.
 *
 * Returns: On success the total size of the PLPKS configured is returned, 0 if
 * not.
 */
u32 plpks_get_totalsize(void)
{
	return totalsize;
}

/**
 * plpks_get_usedspace() - Get the used space from the total size of the PLPKS.
 *
 * Invoke the H_PKS_GET_CONFIG HCALL to refresh the latest value for the used
 * space as this keeps changing with the creation and removal of objects in the
 * PLPKS.
 *
 * Returns: On success the used space is returned, 0 if not.
 */
u32 plpks_get_usedspace(void)
{
	int rc = _plpks_get_config();
	if (rc) {
		pr_err("Couldn't get config, rc: %d\n", rc);
		return 0;
	}
	return usedspace;
}

/**
 * plpks_get_supportedpolicies() - Get a bitmask of the policies supported by
 * the hypervisor.
 *
 * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
 * reads a bitmask of the policies supported by the hypervisor into the file
 * local static supportedpolicies variable.
 *
 * Returns: On success the bitmask of the policies supported by the hypervisor
 * are returned, 0 if not.
 */
u32 plpks_get_supportedpolicies(void)
{
	return supportedpolicies;
}

/**
 * plpks_get_maxlargeobjectsize() - Get the maximum object size supported for
 * PLPKS config structure version >= 3
 *
 * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
 * reads the maximum object size into the local static maxlargeobjectsize
 * variable for PLPKS config structure version >= 3. This was introduced
 * starting with PLPKS config structure version 3 to allow for objects of
 * size >= 64K.
 *
 * Returns: If PLPKS config structure version >= 3 then the new maximum object
 * size is returned, 0 if not.
 */
u32 plpks_get_maxlargeobjectsize(void)
{
	return maxlargeobjectsize;
}

/**
 * plpks_get_signedupdatealgorithms() - Get a bitmask of the signature
 * algorithms supported for signed updates.
 *
 * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
 * reads a bitmask of the signature algorithms supported for signed updates into
 * the file local static signedupdatealgorithms variable. This is valid only
 * when the PLPKS config structure version >= 3.
 *
 * Returns: On success the bitmask of the signature algorithms supported for
 * signed updates is returned, 0 if not.
 */
u64 plpks_get_signedupdatealgorithms(void)
{
	return signedupdatealgorithms;
}

/**
 * plpks_get_wrappingfeatures() - Returns a bitmask of the wrapping features
 * supported by the hypervisor.
 *
 * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
 * reads a bitmask of the wrapping features supported by the hypervisor into the
 * file local static wrappingfeatures variable. This is valid only when the
 * PLPKS config structure version >= 3.
 *
 * Return:
 *	bitmask of the wrapping features supported by the hypervisor
 */
u64 plpks_get_wrappingfeatures(void)
{
	return wrappingfeatures;
}

/**
 * plpks_get_passwordlen() - Get the length of the PLPKS password in bytes.
 *
 * The H_PKS_GEN_PASSWORD HCALL makes the hypervisor generate a random password
 * for the specified consumer, apply that password to the PLPKS and return it to
 * the caller. In this process, the password length for the OS consumer is
 * stored in the local static ospasswordlength variable.
 *
 * Returns: On success the password length for the OS consumer in bytes is
 * returned, 0 if not.
 */
u16 plpks_get_passwordlen(void)
{
	return ospasswordlength;
}

/**
 * plpks_is_available() - Get the PLPKS availability status for the LPAR.
 *
 * The availability of PLPKS is inferred based upon the successful execution of
 * the H_PKS_GET_CONFIG HCALL provided the firmware supports this feature. The
 * H_PKS_GET_CONFIG HCALL reads the configuration and status information related
 * to the PLPKS. The configuration structure provides a version number to inform
 * the caller of the supported features.
 *
 * Returns: true is returned if PLPKS is available, false if not.
 */
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);
}

/**
 * plpks_signed_update_var() - Update the specified authenticated variable.
 * @var: authenticated variable to be updated
 * @flags: signed update request operation flags
 *
 * The H_PKS_SIGNED_UPDATE HCALL performs a signed update to an object in the
 * PLPKS. The object must have the signed update policy flag set.
 *
 * Possible reasons for the returned errno values:
 *
 * -ENXIO	if PLPKS is not supported
 * -EIO		if PLPKS access is blocked due to the LPAR's state
 *		if PLPKS modification is blocked due to the LPAR's state
 *		if an error occurred while processing the request
 * -EINVAL	if invalid authorization parameter
 *		if invalid object label parameter
 *		if invalid object label len parameter
 *		if invalid or unsupported policy declaration
 *		if invalid signed update flags
 *		if invalid input data parameter
 *		if invalid input data len parameter
 *		if invalid continue token parameter
 * -EPERM	if access is denied
 * -ENOMEM	if there is inadequate memory to perform the operation
 * -EBUSY	if unable to handle the request or long running operation
 *		initiated, retry later
 *
 * Returns: On success 0 is returned, a negative errno if not.
 */
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;

	if (var->policy & PLPKS_WRAPPINGKEY)
		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;
}

/**
 * plpks_write_var() - Write the specified variable and its data to PLPKS.
 * @var: variable to be written into the PLPKS
 *
 * The H_PKS_WRITE_OBJECT HCALL writes an object into the PLPKS. The caller must
 * provide a valid component type for the variable, and the signed update policy
 * flag must not be set.
 *
 * Possible reasons for the returned errno values:
 *
 * -ENXIO	if PLPKS is not supported
 * -EIO		if PLPKS access is blocked due to the LPAR's state
 *		if PLPKS modification is blocked due to the LPAR's state
 *		if an error occurred while processing the request
 * -EINVAL	if invalid authorization parameter
 *		if invalid object label parameter
 *		if invalid object label len parameter
 *		if invalid or unsupported policy declaration
 *		if invalid input data parameter
 *		if invalid input data len parameter
 * -EPERM	if access is denied
 * -ENOMEM	if unable to store the requested object in the space available
 * -EBUSY	if unable to handle the request
 * -EEXIST	if the object label already exists
 *
 * Returns: On success 0 is returned, a negative errno if not.
 */
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;

	if (var.policy & PLPKS_WRAPPINGKEY)
		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;
}

/**
 * plpks_remove_var() - Remove the specified variable and its data from PLPKS.
 * @component: metadata prefix in the object label metadata structure
 * @varos: metadata OS flags in the object label metadata structure
 * @vname: object label for the object that needs to be removed
 *
 * The H_PKS_REMOVE_OBJECT HCALL removes an object from the PLPKS. The removal
 * is independent of the policy bits that are set.
 *
 * Possible reasons for the returned errno values:
 *
 * -ENXIO	if PLPKS is not supported
 * -EIO		if PLPKS access is blocked due to the LPAR's state
 *		if PLPKS modification is blocked due to the LPAR's state
 *		if an error occurred while processing the request
 * -EINVAL	if invalid authorization parameter
 *		if invalid object label parameter
 *		if invalid object label len parameter
 * -EPERM	if access is denied
 * -ENOENT	if the requested object was not found
 * -EBUSY	if unable to handle the request
 *
 * Returns: On success 0 is returned, a negative errno if not.
 */
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;

	if (var->policy & PLPKS_WRAPPINGKEY)
		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;
}

/**
 * plpks_wrapping_is_supported() - Get the H_PKS_WRAP_OBJECT interface
 * availability status for the LPAR.
 *
 * Successful execution of the H_PKS_GET_CONFIG HCALL during initialization
 * sets bit 3 of the flags variable in the PLPKS config structure if the
 * H_PKS_WRAP_OBJECT interface is supported.
 *
 * Returns: true if the H_PKS_WRAP_OBJECT interface is supported, false if not.
 */
bool plpks_wrapping_is_supported(void)
{
	return wrapsupport;
}
EXPORT_SYMBOL_GPL(plpks_wrapping_is_supported);

/**
 * plpks_gen_wrapping_key() - Generate a new random key with the 'wrapping key'
 * policy set.
 *
 * The H_PKS_GEN_KEY HCALL makes the hypervisor generate a new random key and
 * store the key in a PLPKS object with the provided object label. With the
 * 'wrapping key' policy set, only the label to the newly generated random key
 * would be visible to the user.
 *
 * Possible reasons for the returned errno values:
 *
 * -ENXIO	if PLPKS is not supported
 * -EIO		if PLPKS access is blocked due to the LPAR's state
 *		if PLPKS modification is blocked due to the LPAR's state
 *		if an error occurred while processing the request
 * -EINVAL	if invalid authorization parameter
 *		if invalid object label parameter
 *		if invalid object label len parameter
 *		if invalid or unsupported policy declaration
 *		if invalid output buffer parameter
 *		if invalid output buffer length parameter
 * -EPERM	if access is denied
 * -ENOMEM	if there is inadequate memory to perform this operation
 * -EBUSY	if unable to handle the request
 * -EEXIST	if the object label already exists
 *
 * Returns: On success 0 is returned, a negative errno if not.
 */
int plpks_gen_wrapping_key(void)
{
	unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
	struct plpks_auth *auth;
	struct label *label;
	int rc = 0, pseries_status = 0;
	struct plpks_var var = {
		.name = PLPKS_WRAPKEY_NAME,
		.namelen = strlen(var.name),
		.policy = PLPKS_WRAPPINGKEY,
		.os = PLPKS_VAR_LINUX,
		.component = PLPKS_WRAPKEY_COMPONENT
	};

	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_GEN_KEY, retbuf,
			 virt_to_phys(auth), virt_to_phys(label),
			 label->size, var.policy,
			 NULL, PLPKS_WRAPPING_KEY_LENGTH);

	if (!rc)
		rc = plpks_confirm_object_flushed(label, auth);

	pseries_status = rc;
	rc = pseries_status_to_err(rc);

	if (rc && rc != -EEXIST) {
		pr_err("H_PKS_GEN_KEY failed. pseries_status=%d, rc=%d",
		       pseries_status, rc);
	} else {
		rc = 0;
	}

	kfree(label);
out:
	kfree(auth);
	return rc;
}
EXPORT_SYMBOL_GPL(plpks_gen_wrapping_key);

/**
 * plpks_wrap_object() - Wrap an object using the default wrapping key stored in
 * the PLPKS.
 * @input_buf: buffer containing the data to be wrapped
 * @input_len: length of the input buffer
 * @wrap_flags: object wrapping flags
 * @output_buf: buffer to store the wrapped data
 * @output_len: length of the output buffer
 *
 * The H_PKS_WRAP_OBJECT HCALL wraps an object using a wrapping key stored in
 * the PLPKS and returns the wrapped object to the caller. The caller provides a
 * label to the wrapping key with the 'wrapping key' policy set that must have
 * been previously created with the H_PKS_GEN_KEY HCALL. The provided object is
 * then encrypted with the wrapping key and additional metadata and the result
 * is returned to the user. The metadata includes the wrapping algorithm and the
 * wrapping key name so those parameters are not required during unwrap.
 *
 * Possible reasons for the returned errno values:
 *
 * -ENXIO	if PLPKS is not supported
 * -EIO		if PLPKS access is blocked due to the LPAR's state
 *		if PLPKS modification is blocked due to the LPAR's state
 *		if an error occurred while processing the request
 * -EINVAL	if invalid authorization parameter
 *		if invalid wrapping key label parameter
 *		if invalid wrapping key label length parameter
 *		if invalid or unsupported object wrapping flags
 *		if invalid input buffer parameter
 *		if invalid input buffer length parameter
 *		if invalid output buffer parameter
 *		if invalid output buffer length parameter
 *		if invalid continue token parameter
 *		if the wrapping key is not compatible with the wrapping
 *		algorithm
 * -EPERM	if access is denied
 * -ENOENT	if the requested wrapping key was not found
 * -EBUSY	if unable to handle the request or long running operation
 *		initiated, retry later.
 *
 * Returns: On success 0 is returned, a negative errno if not.
 */
int plpks_wrap_object(u8 **input_buf, u32 input_len, u16 wrap_flags,
		      u8 **output_buf, u32 *output_len)
{
	unsigned long retbuf[PLPAR_HCALL9_BUFSIZE] = { 0 };
	struct plpks_auth *auth;
	struct label *label;
	u64 continuetoken = 0;
	u64 objwrapflags = 0;
	int rc = 0, pseries_status = 0;
	bool sb_audit_or_enforce_bit = wrap_flags & BIT(0);
	bool sb_enforce_bit = wrap_flags & BIT(1);
	struct plpks_var var = {
		.name = PLPKS_WRAPKEY_NAME,
		.namelen = strlen(var.name),
		.os = PLPKS_VAR_LINUX,
		.component = PLPKS_WRAPKEY_COMPONENT
	};

	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;
	}

	/* Set the consumer password requirement bit. A must have. */
	objwrapflags |= WRAPFLAG_BE_BIT_SET(3);

	/* Set the wrapping algorithm bit. Just one algorithm option for now */
	objwrapflags |= WRAPFLAG_BE_FIELD_PREP(60, 63, 0x1);

	if (sb_audit_or_enforce_bit & sb_enforce_bit) {
		pr_err("Cannot set both audit/enforce and enforce bits.");
		rc = -EINVAL;
		goto out_free_label;
	} else if (sb_audit_or_enforce_bit) {
		objwrapflags |= WRAPFLAG_BE_BIT_SET(1);
	} else if (sb_enforce_bit) {
		objwrapflags |= WRAPFLAG_BE_BIT_SET(2);
	}

	*output_len = input_len + PLPKS_WRAPPING_BUF_DIFF;

	*output_buf = kzalloc(ALIGN(*output_len, PLPKS_WRAPPING_BUF_ALIGN),
			      GFP_KERNEL);
	if (!(*output_buf)) {
		pr_err("Output buffer allocation failed. Returning -ENOMEM.");
		rc = -ENOMEM;
		goto out_free_label;
	}

	do {
		rc = plpar_hcall9(H_PKS_WRAP_OBJECT, retbuf,
				  virt_to_phys(auth), virt_to_phys(label),
				  label->size, objwrapflags,
				  virt_to_phys(*input_buf), input_len,
				  virt_to_phys(*output_buf), *output_len,
				  continuetoken);

		continuetoken = retbuf[0];
		pseries_status = rc;
		rc = pseries_status_to_err(rc);
	} while (rc == -EBUSY);

	if (rc) {
		pr_err("H_PKS_WRAP_OBJECT failed. pseries_status=%d, rc=%d",
		       pseries_status, rc);
		kfree(*output_buf);
		*output_buf = NULL;
	} else {
		*output_len = retbuf[1];
	}

out_free_label:
	kfree(label);
out:
	kfree(auth);
	return rc;
}
EXPORT_SYMBOL_GPL(plpks_wrap_object);

/**
 * plpks_unwrap_object() - Unwrap an object using the default wrapping key
 * stored in the PLPKS.
 * @input_buf: buffer containing the data to be unwrapped
 * @input_len: length of the input buffer
 * @output_buf: buffer to store the unwrapped data
 * @output_len: length of the output buffer
 *
 * The H_PKS_UNWRAP_OBJECT HCALL unwraps an object that was previously wrapped
 * using the H_PKS_WRAP_OBJECT HCALL.
 *
 * Possible reasons for the returned errno values:
 *
 * -ENXIO	if PLPKS is not supported
 * -EIO		if PLPKS access is blocked due to the LPAR's state
 *		if PLPKS modification is blocked due to the LPAR's state
 *		if an error occurred while processing the request
 * -EINVAL	if invalid authorization parameter
 *		if invalid or unsupported object unwrapping flags
 *		if invalid input buffer parameter
 *		if invalid input buffer length parameter
 *		if invalid output buffer parameter
 *		if invalid output buffer length parameter
 *		if invalid continue token parameter
 *		if the wrapping key is not compatible with the wrapping
 *		algorithm
 *		if the wrapped object's format is not supported
 *		if the wrapped object is invalid
 * -EPERM	if access is denied
 * -ENOENT	if the wrapping key for the provided object was not found
 * -EBUSY	if unable to handle the request or long running operation
 *		initiated, retry later.
 *
 * Returns: On success 0 is returned, a negative errno if not.
 */
int plpks_unwrap_object(u8 **input_buf, u32 input_len, u8 **output_buf,
			u32 *output_len)
{
	unsigned long retbuf[PLPAR_HCALL9_BUFSIZE] = { 0 };
	struct plpks_auth *auth;
	u64 continuetoken = 0;
	u64 objwrapflags = 0;
	int rc = 0, pseries_status = 0;

	auth = construct_auth(PLPKS_OS_OWNER);
	if (IS_ERR(auth))
		return PTR_ERR(auth);

	*output_len = input_len - PLPKS_WRAPPING_BUF_DIFF;
	*output_buf = kzalloc(ALIGN(*output_len, PLPKS_WRAPPING_BUF_ALIGN),
			      GFP_KERNEL);
	if (!(*output_buf)) {
		pr_err("Output buffer allocation failed. Returning -ENOMEM.");
		rc = -ENOMEM;
		goto out;
	}

	do {
		rc = plpar_hcall9(H_PKS_UNWRAP_OBJECT, retbuf,
				  virt_to_phys(auth), objwrapflags,
				  virt_to_phys(*input_buf), input_len,
				  virt_to_phys(*output_buf), *output_len,
				  continuetoken);

		continuetoken = retbuf[0];
		pseries_status = rc;
		rc = pseries_status_to_err(rc);
	} while (rc == -EBUSY);

	if (rc) {
		pr_err("H_PKS_UNWRAP_OBJECT failed. pseries_status=%d, rc=%d",
		       pseries_status, rc);
		kfree(*output_buf);
		*output_buf = NULL;
	} else {
		*output_len = retbuf[1];
	}

out:
	kfree(auth);
	return rc;
}
EXPORT_SYMBOL_GPL(plpks_unwrap_object);

/**
 * plpks_read_os_var() - Fetch the data for the specified variable that is owned
 * by the OS consumer.
 * @var: variable to be read from the PLPKS
 *
 * The consumer or the owner of the object is the os kernel. The
 * H_PKS_READ_OBJECT HCALL reads an object from the PLPKS. The caller must
 * allocate the buffer var->data and specify the length for this buffer in
 * var->datalen. If no buffer is provided, var->datalen will be populated with
 * the requested object's size.
 *
 * Possible reasons for the returned errno values:
 *
 * -ENXIO	if PLPKS is not supported
 * -EIO		if PLPKS access is blocked due to the LPAR's state
 *		if an error occurred while processing the request
 * -EINVAL	if invalid authorization parameter
 *		if invalid object label parameter
 *		if invalid object label len parameter
 *		if invalid output data parameter
 *		if invalid output data len parameter
 * -EPERM	if access is denied
 * -ENOENT	if the requested object was not found
 * -EFBIG	if the requested object couldn't be
 *		stored in the buffer provided
 * -EBUSY	if unable to handle the request
 *
 * Returns: On success 0 is returned, a negative errno if not.
 */
int plpks_read_os_var(struct plpks_var *var)
{
	return plpks_read_var(PLPKS_OS_OWNER, var);
}

/**
 * plpks_read_fw_var() - Fetch the data for the specified variable that is
 * owned by the firmware consumer.
 * @var: variable to be read from the PLPKS
 *
 * The consumer or the owner of the object is the firmware. The
 * H_PKS_READ_OBJECT HCALL reads an object from the PLPKS. The caller must
 * allocate the buffer var->data and specify the length for this buffer in
 * var->datalen. If no buffer is provided, var->datalen will be populated with
 * the requested object's size.
 *
 * Possible reasons for the returned errno values:
 *
 * -ENXIO	if PLPKS is not supported
 * -EIO		if PLPKS access is blocked due to the LPAR's state
 *		if an error occurred while processing the request
 * -EINVAL	if invalid authorization parameter
 *		if invalid object label parameter
 *		if invalid object label len parameter
 *		if invalid output data parameter
 *		if invalid output data len parameter
 * -EPERM	if access is denied
 * -ENOENT	if the requested object was not found
 * -EFBIG	if the requested object couldn't be
 *		stored in the buffer provided
 * -EBUSY	if unable to handle the request
 *
 * Returns: On success 0 is returned, a negative errno if not.
 */
int plpks_read_fw_var(struct plpks_var *var)
{
	return plpks_read_var(PLPKS_FW_OWNER, var);
}

/**
 * plpks_read_bootloader_var() - Fetch the data for the specified variable
 * owned by the bootloader consumer.
 * @var: variable to be read from the PLPKS
 *
 * The consumer or the owner of the object is the bootloader. The
 * H_PKS_READ_OBJECT HCALL reads an object from the PLPKS. The caller must
 * allocate the buffer var->data and specify the length for this buffer in
 * var->datalen. If no buffer is provided, var->datalen will be populated with
 * the requested object's size.
 *
 * Possible reasons for the returned errno values:
 *
 * -ENXIO	if PLPKS is not supported
 * -EIO		if PLPKS access is blocked due to the LPAR's state
 *		if an error occurred while processing the request
 * -EINVAL	if invalid authorization parameter
 *		if invalid object label parameter
 *		if invalid object label len parameter
 *		if invalid output data parameter
 *		if invalid output data len parameter
 * -EPERM	if access is denied
 * -ENOENT	if the requested object was not found
 * -EFBIG	if the requested object couldn't be
 *		stored in the buffer provided
 * -EBUSY	if unable to handle the request
 *
 * Returns: On success 0 is returned, a negative errno if not.
 */
int plpks_read_bootloader_var(struct plpks_var *var)
{
	return plpks_read_var(PLPKS_BOOTLOADER_OWNER, var);
}

/**
 * plpks_populate_fdt(): Populates the FDT with the PLPKS password to prepare
 * for kexec.
 * @fdt: pointer to the device tree blob
 *
 * Upon confirming the existence of the chosen node, invoke fdt_setprop to
 * populate the device tree with the PLPKS password in order to prepare for
 * kexec.
 *
 * Returns: On success 0 is returned, a negative value if not.
 */
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);
}

/**
 * plpks_early_init_devtree() - Retrieves and clears the PLPKS password from the
 * DT in early init.
 *
 * 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, __pa(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);