xref: /optee_os/ta/pkcs11/src/processing.c (revision 4dad6642f7009ed11de0d69769f5af15a8458ba7)

// SPDX-License-Identifier: BSD-2-Clause
/*
 * Copyright (c) 2017-2020, Linaro Limited
 */

#include <assert.h>
#include <pkcs11_ta.h>
#include <string.h>
#include <tee_api_defines.h>
#include <tee_internal_api.h>
#include <tee_internal_api_extensions.h>
#include <util.h>

#include "attributes.h"
#include "object.h"
#include "pkcs11_attributes.h"
#include "pkcs11_helpers.h"
#include "pkcs11_token.h"
#include "processing.h"
#include "serializer.h"

static enum pkcs11_rc get_ready_session(struct pkcs11_session *session)
{
	if (session_is_active(session))
		return PKCS11_CKR_OPERATION_ACTIVE;

	return PKCS11_CKR_OK;
}

static bool func_matches_state(enum processing_func function,
			       enum pkcs11_proc_state state)
{
	switch (function) {
	case PKCS11_FUNCTION_ENCRYPT:
		return state == PKCS11_SESSION_ENCRYPTING ||
		       state == PKCS11_SESSION_DIGESTING_ENCRYPTING ||
		       state == PKCS11_SESSION_SIGNING_ENCRYPTING;
	case PKCS11_FUNCTION_DECRYPT:
		return state == PKCS11_SESSION_DECRYPTING ||
		       state == PKCS11_SESSION_DECRYPTING_DIGESTING ||
		       state == PKCS11_SESSION_DECRYPTING_VERIFYING;
	case PKCS11_FUNCTION_DIGEST:
		return state == PKCS11_SESSION_DIGESTING ||
		       state == PKCS11_SESSION_DIGESTING_ENCRYPTING;
	case PKCS11_FUNCTION_SIGN:
		return state == PKCS11_SESSION_SIGNING ||
		       state == PKCS11_SESSION_SIGNING_ENCRYPTING;
	case PKCS11_FUNCTION_VERIFY:
		return state == PKCS11_SESSION_VERIFYING ||
		       state == PKCS11_SESSION_DECRYPTING_VERIFYING;
	case PKCS11_FUNCTION_SIGN_RECOVER:
		return state == PKCS11_SESSION_SIGNING_RECOVER;
	case PKCS11_FUNCTION_VERIFY_RECOVER:
		return state == PKCS11_SESSION_SIGNING_RECOVER;
	default:
		TEE_Panic(function);
		return false;
	}
}

static enum pkcs11_rc get_active_session(struct pkcs11_session *session,
					 enum processing_func function)
{
	enum pkcs11_rc rc = PKCS11_CKR_OPERATION_NOT_INITIALIZED;

	if (session->processing &&
	    func_matches_state(function, session->processing->state))
		rc = PKCS11_CKR_OK;

	return rc;
}

void release_active_processing(struct pkcs11_session *session)
{
	if (!session->processing)
		return;

	if (session->processing->tee_op_handle != TEE_HANDLE_NULL) {
		TEE_FreeOperation(session->processing->tee_op_handle);
		session->processing->tee_op_handle = TEE_HANDLE_NULL;
	}

	TEE_Free(session->processing->extra_ctx);

	TEE_Free(session->processing);
	session->processing = NULL;
}

size_t get_object_key_bit_size(struct pkcs11_object *obj)
{
	uint32_t a_size = 0;
	struct obj_attrs *attrs = obj->attributes;

	switch (get_key_type(attrs)) {
	case PKCS11_CKK_AES:
	case PKCS11_CKK_GENERIC_SECRET:
	case PKCS11_CKK_MD5_HMAC:
	case PKCS11_CKK_SHA_1_HMAC:
	case PKCS11_CKK_SHA224_HMAC:
	case PKCS11_CKK_SHA256_HMAC:
	case PKCS11_CKK_SHA384_HMAC:
	case PKCS11_CKK_SHA512_HMAC:
		if (get_attribute_ptr(attrs, PKCS11_CKA_VALUE, NULL, &a_size))
			return 0;

		return a_size * 8;
	default:
		TEE_Panic(0);
		return 0;
	}
}

static enum pkcs11_rc generate_random_key_value(struct obj_attrs **head)
{
	enum pkcs11_rc rc = PKCS11_CKR_GENERAL_ERROR;
	void *data = NULL;
	uint32_t data_size = 0;
	uint32_t value_len = 0;
	void *value = NULL;

	if (!*head)
		return PKCS11_CKR_TEMPLATE_INCONSISTENT;

	rc = get_attribute_ptr(*head, PKCS11_CKA_VALUE_LEN, &data, &data_size);
	if (rc || data_size != sizeof(uint32_t)) {
		DMSG("%s", rc ? "No attribute value_len found" :
		     "Invalid size for attribute VALUE_LEN");

		return PKCS11_CKR_ATTRIBUTE_VALUE_INVALID;
	}
	TEE_MemMove(&value_len, data, data_size);

	/* Remove the default empty value attribute if found */
	rc = remove_empty_attribute(head, PKCS11_CKA_VALUE);
	if (rc != PKCS11_CKR_OK && rc != PKCS11_RV_NOT_FOUND)
		return PKCS11_CKR_GENERAL_ERROR;

	value = TEE_Malloc(value_len, TEE_USER_MEM_HINT_NO_FILL_ZERO);
	if (!value)
		return PKCS11_CKR_DEVICE_MEMORY;

	TEE_GenerateRandom(value, value_len);

	rc = add_attribute(head, PKCS11_CKA_VALUE, value, value_len);

	TEE_Free(value);

	return rc;
}

enum pkcs11_rc entry_generate_secret(struct pkcs11_client *client,
				     uint32_t ptypes, TEE_Param *params)
{
	const uint32_t exp_pt = TEE_PARAM_TYPES(TEE_PARAM_TYPE_MEMREF_INOUT,
						TEE_PARAM_TYPE_NONE,
						TEE_PARAM_TYPE_MEMREF_OUTPUT,
						TEE_PARAM_TYPE_NONE);
	TEE_Param *ctrl = params;
	TEE_Param *out = params + 2;
	enum pkcs11_rc rc = PKCS11_CKR_GENERAL_ERROR;
	struct serialargs ctrlargs = { };
	struct pkcs11_session *session = NULL;
	struct pkcs11_attribute_head *proc_params = NULL;
	struct obj_attrs *head = NULL;
	struct pkcs11_object_head *template = NULL;
	size_t template_size = 0;
	uint32_t obj_handle = 0;

	if (!client || ptypes != exp_pt ||
	    out->memref.size != sizeof(obj_handle))
		return PKCS11_CKR_ARGUMENTS_BAD;

	serialargs_init(&ctrlargs, ctrl->memref.buffer, ctrl->memref.size);

	rc = serialargs_get_session_from_handle(&ctrlargs, client, &session);
	if (rc)
		return rc;

	rc = serialargs_alloc_get_one_attribute(&ctrlargs, &proc_params);
	if (rc)
		goto out;

	rc = serialargs_alloc_get_attributes(&ctrlargs, &template);
	if (rc)
		goto out;

	if (serialargs_remaining_bytes(&ctrlargs)) {
		rc = PKCS11_CKR_ARGUMENTS_BAD;
		goto out;
	}

	rc = get_ready_session(session);
	if (rc)
		goto out;

	template_size = sizeof(*template) + template->attrs_size;

	rc = check_mechanism_against_processing(session, proc_params->id,
						PKCS11_FUNCTION_GENERATE,
						PKCS11_FUNC_STEP_INIT);
	if (rc) {
		DMSG("Invalid mechanism %#"PRIx32": %#x", proc_params->id, rc);
		goto out;
	}

	/*
	 * Prepare a clean initial state for the requested object attributes.
	 * Free temporary template once done.
	 */
	rc = create_attributes_from_template(&head, template, template_size,
					     NULL, PKCS11_FUNCTION_GENERATE,
					     proc_params->id,
					     PKCS11_CKO_UNDEFINED_ID);
	if (rc)
		goto out;

	TEE_Free(template);
	template = NULL;

	rc = check_created_attrs(head, NULL);
	if (rc)
		goto out;

	rc = check_created_attrs_against_processing(proc_params->id, head);
	if (rc)
		goto out;

	rc = check_created_attrs_against_token(session, head);
	if (rc)
		goto out;

	/*
	 * Execute target processing and add value as attribute
	 * PKCS11_CKA_VALUE. Symm key generation: depends on target
	 * processing to be used.
	 */
	switch (proc_params->id) {
	case PKCS11_CKM_GENERIC_SECRET_KEY_GEN:
	case PKCS11_CKM_AES_KEY_GEN:
		/* Generate random of size specified by attribute VALUE_LEN */
		rc = generate_random_key_value(&head);
		if (rc)
			goto out;
		break;

	default:
		rc = PKCS11_CKR_MECHANISM_INVALID;
		goto out;
	}

	TEE_Free(proc_params);
	proc_params = NULL;

	/*
	 * Object is ready, register it and return a handle.
	 */
	rc = create_object(session, head, &obj_handle);
	if (rc)
		goto out;

	/*
	 * Now obj_handle (through the related struct pkcs11_object instance)
	 * owns the serialized buffer that holds the object attributes.
	 * We reset head to NULL as it is no more the buffer owner and would
	 * be freed at function out.
	 */
	head = NULL;

	TEE_MemMove(out->memref.buffer, &obj_handle, sizeof(obj_handle));
	out->memref.size = sizeof(obj_handle);

	DMSG("PKCS11 session %"PRIu32": generate secret %#"PRIx32,
	     session->handle, obj_handle);

out:
	TEE_Free(proc_params);
	TEE_Free(template);
	TEE_Free(head);

	return rc;
}

/*
 * entry_processing_init - Generic entry for initializing a processing
 *
 * @client = client reference
 * @ptype = Invocation parameter types
 * @params = Invocation parameters reference
 * @function - encrypt, decrypt, sign, verify, digest, ...
 */
enum pkcs11_rc entry_processing_init(struct pkcs11_client *client,
				     uint32_t ptypes, TEE_Param *params,
				     enum processing_func function)
{
	const uint32_t exp_pt = TEE_PARAM_TYPES(TEE_PARAM_TYPE_MEMREF_INOUT,
						TEE_PARAM_TYPE_NONE,
						TEE_PARAM_TYPE_NONE,
						TEE_PARAM_TYPE_NONE);
	TEE_Param *ctrl = params;
	enum pkcs11_rc rc = PKCS11_CKR_OK;
	struct serialargs ctrlargs = { };
	struct pkcs11_session *session = NULL;
	struct pkcs11_attribute_head *proc_params = NULL;
	uint32_t key_handle = 0;
	struct pkcs11_object *obj = NULL;

	if (!client || ptypes != exp_pt)
		return PKCS11_CKR_ARGUMENTS_BAD;

	serialargs_init(&ctrlargs, ctrl->memref.buffer, ctrl->memref.size);

	rc = serialargs_get_session_from_handle(&ctrlargs, client, &session);
	if (rc)
		return rc;

	rc = serialargs_get(&ctrlargs, &key_handle, sizeof(uint32_t));
	if (rc)
		return rc;

	rc = serialargs_alloc_get_one_attribute(&ctrlargs, &proc_params);
	if (rc)
		return rc;

	if (serialargs_remaining_bytes(&ctrlargs)) {
		rc = PKCS11_CKR_ARGUMENTS_BAD;
		goto out;
	}

	rc = get_ready_session(session);
	if (rc)
		goto out;

	obj = pkcs11_handle2object(key_handle, session);
	if (!obj) {
		rc = PKCS11_CKR_KEY_HANDLE_INVALID;
		goto out;
	}

	rc = set_processing_state(session, function, obj, NULL);
	if (rc)
		goto out;

	rc = check_mechanism_against_processing(session, proc_params->id,
						function,
						PKCS11_FUNC_STEP_INIT);
	if (rc)
		goto out;

	rc = check_parent_attrs_against_processing(proc_params->id, function,
						   obj->attributes);
	if (rc)
		goto out;

	rc = check_access_attrs_against_token(session, obj->attributes);
	if (rc)
		goto out;

	if (processing_is_tee_symm(proc_params->id))
		rc = init_symm_operation(session, function, proc_params, obj);
	else
		rc = PKCS11_CKR_MECHANISM_INVALID;

	if (rc == PKCS11_CKR_OK) {
		session->processing->mecha_type = proc_params->id;
		DMSG("PKCS11 session %"PRIu32": init processing %s %s",
		     session->handle, id2str_proc(proc_params->id),
		     id2str_function(function));
	}

out:
	if (rc && session)
		release_active_processing(session);

	TEE_Free(proc_params);

	return rc;
}

/*
 * entry_processing_step - Generic entry on active processing
 *
 * @client = client reference
 * @ptype = Invocation parameter types
 * @params = Invocation parameters reference
 * @function - encrypt, decrypt, sign, verify, digest, ...
 * @step - update, oneshot, final
 */
enum pkcs11_rc entry_processing_step(struct pkcs11_client *client,
				     uint32_t ptypes, TEE_Param *params,
				     enum processing_func function,
				     enum processing_step step)
{
	TEE_Param *ctrl = params;
	enum pkcs11_rc rc = PKCS11_CKR_OK;
	struct serialargs ctrlargs = { };
	struct pkcs11_session *session = NULL;
	enum pkcs11_mechanism_id mecha_type = PKCS11_CKM_UNDEFINED_ID;

	if (!client ||
	    TEE_PARAM_TYPE_GET(ptypes, 0) != TEE_PARAM_TYPE_MEMREF_INOUT)
		return PKCS11_CKR_ARGUMENTS_BAD;

	serialargs_init(&ctrlargs, ctrl->memref.buffer, ctrl->memref.size);

	rc = serialargs_get_session_from_handle(&ctrlargs, client, &session);
	if (rc)
		return rc;

	if (serialargs_remaining_bytes(&ctrlargs))
		return PKCS11_CKR_ARGUMENTS_BAD;

	rc = get_active_session(session, function);
	if (rc)
		return rc;

	mecha_type = session->processing->mecha_type;
	rc = check_mechanism_against_processing(session, mecha_type,
						function, step);
	if (rc)
		goto out;

	if (processing_is_tee_symm(mecha_type))
		rc = step_symm_operation(session, function, step,
					 ptypes, params);
	else
		rc = PKCS11_CKR_MECHANISM_INVALID;

	if (rc == PKCS11_CKR_OK && step == PKCS11_FUNC_STEP_UPDATE) {
		session->processing->updated = true;
		DMSG("PKCS11 session%"PRIu32": processing %s %s",
		     session->handle, id2str_proc(mecha_type),
		     id2str_function(function));
	}

out:
	switch (step) {
	case PKCS11_FUNC_STEP_UPDATE:
		if (rc != PKCS11_CKR_OK && rc != PKCS11_CKR_BUFFER_TOO_SMALL)
			release_active_processing(session);
		break;
	default:
		/* ONESHOT and FINAL terminates processing on success */
		if (rc != PKCS11_CKR_BUFFER_TOO_SMALL)
			release_active_processing(session);
		break;
	}

	return rc;
}

enum pkcs11_rc entry_processing_key(struct pkcs11_client *client,
				    uint32_t ptypes, TEE_Param *params,
				    enum processing_func function)
{
	const uint32_t exp_pt = TEE_PARAM_TYPES(TEE_PARAM_TYPE_MEMREF_INOUT,
						TEE_PARAM_TYPE_NONE,
						TEE_PARAM_TYPE_MEMREF_OUTPUT,
						TEE_PARAM_TYPE_NONE);
	TEE_Param *ctrl = params;
	TEE_Param *out = params + 2;
	enum pkcs11_rc rc = PKCS11_CKR_GENERAL_ERROR;
	struct serialargs ctrlargs = { };
	struct pkcs11_session *session = NULL;
	struct pkcs11_attribute_head *proc_params = NULL;
	struct pkcs11_object_head *template = NULL;
	uint32_t parent_handle = 0;
	uint32_t obj_handle = 0;
	struct pkcs11_object *parent = NULL;
	struct obj_attrs *head = NULL;
	size_t template_size = 0;
	void *out_buf = NULL;
	uint32_t out_size = 0;

	if (!client || ptypes != exp_pt ||
	    out->memref.size != sizeof(obj_handle))
		return PKCS11_CKR_ARGUMENTS_BAD;

	serialargs_init(&ctrlargs, ctrl->memref.buffer, ctrl->memref.size);

	rc = serialargs_get_session_from_handle(&ctrlargs, client, &session);
	if (rc)
		return rc;

	rc = serialargs_get(&ctrlargs, &parent_handle, sizeof(uint32_t));
	if (rc)
		return rc;

	rc = serialargs_alloc_get_one_attribute(&ctrlargs, &proc_params);
	if (rc)
		goto out_free;

	rc = serialargs_alloc_get_attributes(&ctrlargs, &template);
	if (rc)
		goto out_free;

	if (serialargs_remaining_bytes(&ctrlargs)) {
		rc = PKCS11_CKR_ARGUMENTS_BAD;
		goto out_free;
	}

	/* Return error if processing already active */
	rc = get_ready_session(session);
	if (rc)
		goto out_free;

	/* Check parent handle */
	parent = pkcs11_handle2object(parent_handle, session);
	if (!parent) {
		rc = PKCS11_CKR_KEY_HANDLE_INVALID;
		goto out_free;
	}

	/* Check if mechanism can be used for derivation function */
	rc = check_mechanism_against_processing(session, proc_params->id,
						function,
						PKCS11_FUNC_STEP_INIT);
	if (rc)
		goto out_free;

	/* Set the processing state to active */
	rc = set_processing_state(session, function, parent, NULL);
	if (rc)
		goto out_free;

	/*
	 * Check if base/parent key has CKA_DERIVE set and its key type is
	 * compatible with the mechanism passed
	 */
	rc = check_parent_attrs_against_processing(proc_params->id, function,
						   parent->attributes);
	if (rc)
		goto out;

	/* Check access of base/parent key */
	rc = check_access_attrs_against_token(session, parent->attributes);
	if (rc)
		goto out;

	template_size = sizeof(*template) + template->attrs_size;
	/*
	 * Prepare a clean initial state for the requested object attributes
	 * using base/parent key attributes. Free temporary template once done.
	 */
	rc = create_attributes_from_template(&head, template, template_size,
					     parent->attributes,
					     function,
					     proc_params->id,
					     PKCS11_CKO_UNDEFINED_ID);
	if (rc)
		goto out;

	TEE_Free(template);
	template = NULL;

	/* check_created_attrs() is called later once key size is known */

	rc = check_created_attrs_against_processing(proc_params->id, head);
	if (rc)
		goto out;

	rc = check_created_attrs_against_token(session, head);
	if (rc)
		goto out;

	if (processing_is_tee_symm(proc_params->id)) {
		/*
		 * These derivation mechanism require encryption to be
		 * performed on the data passed in proc_params by parent
		 * key. Hence pass function as PKCS11_FUNCTION_ENCRYPT
		 * to init_symm_operation()
		 */
		rc = init_symm_operation(session, PKCS11_FUNCTION_ENCRYPT,
					 proc_params, parent);
		if (rc)
			goto out;

		session->processing->mecha_type = proc_params->id;

		rc = derive_key_by_symm_enc(session, &out_buf, &out_size);
		if (rc)
			goto out;
	} else {
		rc = PKCS11_CKR_MECHANISM_INVALID;
		goto out;
	}

	rc = set_key_data(&head, out_buf, out_size);
	if (rc)
		goto out;

	TEE_Free(out_buf);
	out_buf = NULL;

	TEE_Free(proc_params);
	proc_params = NULL;

	/*
	 * Object is ready, register it and return a handle.
	 */
	rc = create_object(session, head, &obj_handle);
	if (rc)
		goto out;

	/*
	 * Now obj_handle (through the related struct pkcs11_object instance)
	 * owns the serialized buffer that holds the object attributes.
	 * We reset head to NULL as it is no more the buffer owner and would
	 * be freed at function out.
	 */
	head = NULL;

	TEE_MemMove(out->memref.buffer, &obj_handle, sizeof(obj_handle));
	out->memref.size = sizeof(obj_handle);

	DMSG("PKCS11 session %"PRIu32": derive secret %#"PRIx32,
	     session->handle, obj_handle);

out:
	release_active_processing(session);
out_free:
	TEE_Free(proc_params);
	TEE_Free(template);
	TEE_Free(head);
	TEE_Free(out_buf);

	return rc;
}