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/*
* Copyright (c) 2017, Linaro Limited
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __TEE_FS_HTREE_H
#define __TEE_FS_HTREE_H
/*
* The purpose of this API is to provide file integrity and confidentiality
* in order to implement secure storage. On-disk data structures are
* duplicated to make updates atomic, an update is finalized to disk with
* tee_fs_htree_sync_to_storage().
*
* This implementation doesn't provide rollback protection, it only
* guarantees the integrity and confidentiality of the file.
*/
#include <tee_api_types.h>
#include <utee_defines.h>
#define TEE_FS_HTREE_HASH_SIZE TEE_SHA256_HASH_SIZE
#define TEE_FS_HTREE_IV_SIZE 16
#define TEE_FS_HTREE_FEK_SIZE 16
#define TEE_FS_HTREE_TAG_SIZE 16
/* Internal struct provided to let the rpc callbacks know the size if needed */
struct tee_fs_htree_node_image {
/* Note that calc_node_hash() depends on hash first in struct */
uint8_t hash[TEE_FS_HTREE_HASH_SIZE];
uint8_t iv[TEE_FS_HTREE_IV_SIZE];
uint8_t tag[TEE_FS_HTREE_TAG_SIZE];
uint16_t flags;
};
/*
* This struct is not interpreted by the hash tree, it's up to the user of
* the interface to update etc if needed.
*/
struct tee_fs_htree_meta {
uint64_t length;
};
/* Internal struct needed by struct tee_fs_htree_image */
struct tee_fs_htree_imeta {
struct tee_fs_htree_meta meta;
uint32_t max_node_id;
};
/* Internal struct provided to let the rpc callbacks know the size if needed */
struct tee_fs_htree_image {
uint8_t iv[TEE_FS_HTREE_IV_SIZE];
uint8_t tag[TEE_FS_HTREE_TAG_SIZE];
uint8_t enc_fek[TEE_FS_HTREE_FEK_SIZE];
uint8_t imeta[sizeof(struct tee_fs_htree_imeta)];
uint32_t counter;
};
/**
* enum tee_fs_htree_type - type of hash tree element
* @TEE_FS_HTREE_TYPE_HEAD: indicates a struct tee_fs_htree_image
* @TEE_FS_HTREE_TYPE_NODE: indicates a struct tee_fs_htree_node_image
* @TEE_FS_HTREE_TYPE_BLOCK: indicates a data block
*/
enum tee_fs_htree_type {
TEE_FS_HTREE_TYPE_HEAD,
TEE_FS_HTREE_TYPE_NODE,
TEE_FS_HTREE_TYPE_BLOCK,
};
struct tee_fs_rpc_operation;
/**
* struct tee_fs_htree_storage - storage description supplied by user of
* this interface
* @block_size: size of data blocks
* @rpc_read_init: initialize a struct tee_fs_rpc_operation for an RPC read
* operation
* @rpc_write_init: initialize a struct tee_fs_rpc_operation for an RPC
* write operation
*
* The @idx arguments starts counting from 0. The @vers arguments are either
* 0 or 1. The @data arguments is a pointer to a buffer in non-secure shared
* memory where the encrypted data is stored.
*/
struct tee_fs_htree_storage {
size_t block_size;
TEE_Result (*rpc_read_init)(void *aux, struct tee_fs_rpc_operation *op,
enum tee_fs_htree_type type, size_t idx,
uint8_t vers, void **data);
TEE_Result (*rpc_read_final)(struct tee_fs_rpc_operation *op,
size_t *bytes);
TEE_Result (*rpc_write_init)(void *aux, struct tee_fs_rpc_operation *op,
enum tee_fs_htree_type type, size_t idx,
uint8_t vers, void **data);
TEE_Result (*rpc_write_final)(struct tee_fs_rpc_operation *op);
};
struct tee_fs_htree;
/**
* tee_fs_htree_open() - opens/creates a hash tree
* @create: true if a new hash tree is to be created, else the hash tree
* is read in and verified
* @stor: storage description
* @stor_aux: auxilary pointer supplied to callbacks in struct
* tee_fs_htree_storage
* @ht: returned hash tree on success
*/
TEE_Result tee_fs_htree_open(bool create,
const struct tee_fs_htree_storage *stor,
void *stor_aux, struct tee_fs_htree **ht);
/**
* tee_fs_htree_close() - close a hash tree
* @ht: hash tree
*/
void tee_fs_htree_close(struct tee_fs_htree **ht);
/**
* tee_fs_htree_get_meta() - get a pointer to associated struct
* tee_fs_htree_meta
* @ht: hash tree
*/
struct tee_fs_htree_meta *tee_fs_htree_get_meta(struct tee_fs_htree *ht);
/**
* tee_fs_htree_sync_to_storage() - synchronize hash tree to storage
* @ht: hash tree
*
* Frees the hash tree and sets *ht to NULL on failure and returns an error code
*/
TEE_Result tee_fs_htree_sync_to_storage(struct tee_fs_htree **ht);
/**
* tee_fs_htree_truncate() - truncate a hash tree
* @ht: hash tree
* @block_num: the number of nodes to truncate to
*
* Frees the hash tree and sets *ht to NULL on failure and returns an error code
*/
TEE_Result tee_fs_htree_truncate(struct tee_fs_htree **ht, size_t block_num);
/**
* tee_fs_htree_write_block() - encrypt and write a data block to storage
* @ht: hash tree
* @block_num: block number
* @block: pointer to a block of stor->block_size size
*
* Frees the hash tree and sets *ht to NULL on failure and returns an error code
*/
TEE_Result tee_fs_htree_write_block(struct tee_fs_htree **ht, size_t block_num,
const void *block);
/**
* tee_fs_htree_write_block() - read and decrypt a data block from storage
* @ht: hash tree
* @block_num: block number
* @block: pointer to a block of stor->block_size size
*
* Frees the hash tree and sets *ht to NULL on failure and returns an error code
*/
TEE_Result tee_fs_htree_read_block(struct tee_fs_htree **ht, size_t block_num,
void *block);
#endif /*__TEE_FS_HTREE_H*/
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