/**
* libkeccak – Keccak-family hashing library
*
* Copyright © 2014, 2015 Mattias Andrée (maandree@member.fsf.org)
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef LIBKECCAK_STATE_H
#define LIBKECCAK_STATE_H 1
#include "spec.h"
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
/**
* Datastructure that describes the state of a hashing process
*
* The `char`-size of the output hashsum is calculated by `(.n + 7) / 8`
*/
typedef struct libkeccak_state
{
/**
* The lanes (state/sponge)
*/
int64_t S[25];
/**
* The bitrate
*/
long r;
/**
* The capacity
*/
long c;
/**
* The output size
*/
long n;
/**
* The state size
*/
long b;
/**
* The word size
*/
long w;
/**
* The word mask
*/
int64_t wmod;
/**
* ℓ, the binary logarithm of the word size
*/
long l;
/**
* 12 + 2ℓ, the number of rounds
*/
long nr;
/**
* Pointer for `M`
*/
size_t mptr;
/**
* Size of `M`
*/
size_t mlen;
/**
* Left over water to fill the sponge with at next update
*/
char* M;
} libkeccak_state_t;
/**
* Initialise a state according to hashing specifications
*
* @param state The state that should be initialised
* @param spec The specifications for the state
* @return Zero on success, -1 on error
*/
__attribute__((leaf, nonnull))
int libkeccak_state_initialise(libkeccak_state_t* restrict state, const libkeccak_spec_t* restrict spec);
/**
* Reset a state according to hashing specifications
*
* @param state The state that should be reset
*/
static inline __attribute__((nonnull, nothrow, unused))
void libkeccak_state_reset(libkeccak_state_t* restrict state)
{
state->mptr = 0;
memset(state->S, 0, sizeof(state->S));
}
/**
* Release resources allocation for a state without wiping sensitive data
*
* @param state The state that should be destroyed
*/
static inline
void libkeccak_state_fast_destroy(libkeccak_state_t* restrict state)
{
if (state == NULL)
return;
free(state->M);
state->M = NULL;
}
/**
* Wipe data in the state's message wihout freeing any data
*
* @param state The state that should be wipe
*/
__attribute__((leaf, nonnull, nothrow, optimize("-O0")))
void libkeccak_state_wipe_message(volatile libkeccak_state_t* restrict state);
/**
* Wipe data in the state's sponge wihout freeing any data
*
* @param state The state that should be wipe
*/
__attribute__((leaf, nonnull, nothrow, optimize("-O0")))
void libkeccak_state_wipe_sponge(volatile libkeccak_state_t* restrict state);
/**
* Wipe sensitive data wihout freeing any data
*
* @param state The state that should be wipe
*/
__attribute__((nonnull, nothrow, optimize("-O0")))
void libkeccak_state_wipe(volatile libkeccak_state_t* restrict state);
/**
* Release resources allocation for a state and wipe sensitive data
*
* @param state The state that should be destroyed
*/
static inline __attribute__((unused, optimize("-O0")))
void libkeccak_state_destroy(volatile libkeccak_state_t* restrict state)
{
if (state == NULL)
return;
libkeccak_state_wipe(state);
free(state->M);
state->M = NULL;
}
/**
* Wrapper for `libkeccak_state_initialise` that also allocates the states
*
* @param spec The specifications for the state
* @return The state, `NULL` on error
*/
static inline __attribute__((nonnull, unused, warn_unused_result, malloc))
libkeccak_state_t* libkeccak_state_create(const libkeccak_spec_t* restrict spec)
{
libkeccak_state_t* restrict state = malloc(sizeof(libkeccak_state_t));
int saved_errno;
if ((state == NULL) || libkeccak_state_initialise(state, spec))
return saved_errno = errno, free(state), errno = saved_errno, NULL;
return state;
}
/**
* Wrapper for `libkeccak_state_fast_destroy` that also frees the allocation of the state
*
* @param state The state that should be freed
*/
static inline __attribute__((unused))
void libkeccak_state_fast_free(libkeccak_state_t* restrict state)
{
libkeccak_state_fast_destroy(state);
free(state);
}
/**
* Wrapper for `libkeccak_state_destroy` that also frees the allocation of the state
*
* @param state The state that should be freed
*/
static inline __attribute__((unused, optimize("-O0")))
void libkeccak_state_free(volatile libkeccak_state_t* restrict state)
{
#ifdef __GNUC__
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wcast-qual"
#endif
libkeccak_state_destroy(state);
free((libkeccak_state_t*)state);
#ifdef __GNUC__
# pragma GCC diagnostic pop
#endif
}
/**
* Make a copy of a state
*
* @param dest The slot for the duplicate, must not be initialised (memory leak otherwise)
* @param src The state to duplicate
* @return Zero on success, -1 on error
*/
__attribute__((leaf, nonnull))
int libkeccak_state_copy(libkeccak_state_t* restrict dest, const libkeccak_state_t* restrict src);
/**
* A wrapper for `libkeccak_state_copy` that also allocates the duplicate
*
* @param src The state to duplicate
* @return The duplicate, `NULL` on error
*/
static inline __attribute__((nonnull, unused, warn_unused_result, malloc))
libkeccak_state_t* libkeccak_state_duplicate(const libkeccak_state_t* restrict src)
{
libkeccak_state_t* restrict dest = malloc(sizeof(libkeccak_state_t));
int saved_errno;
if ((dest == NULL) || libkeccak_state_copy(dest, src))
return saved_errno = errno, libkeccak_state_free(dest), errno = saved_errno, NULL;
return dest;
}
/**
* Calculates the allocation size required for the second argument
* of `libkeccak_state_marshal` (`char* restrict data)`)
*
* @param state The state as it will be marshalled by a subsequent call to `libkeccak_state_marshal`
* @return The allocation size needed for the buffer to which the state will be marshalled
*/
static inline __attribute__((nonnull, nothrow, unused, warn_unused_result, pure))
size_t libkeccak_state_marshal_size(const libkeccak_state_t* restrict state)
{
return sizeof(libkeccak_state_t) - sizeof(char*) + state->mptr * sizeof(char);
}
/**
* Marshal a `libkeccak_state_t` into a buffer
*
* @param state The state to marshal
* @param data The output buffer
* @return The number of bytes stored to `data`
*/
__attribute__((leaf, nonnull, nothrow))
size_t libkeccak_state_marshal(const libkeccak_state_t* restrict state, char* restrict data);
/**
* Unmarshal a `libkeccak_state_t` from a buffer
*
* @param state The slot for the unmarshalled state, must not be initialised (memory leak otherwise)
* @param data The input buffer
* @return The number of bytes read from `data`, 0 on error
*/
__attribute__((leaf, nonnull))
size_t libkeccak_state_unmarshal(libkeccak_state_t* restrict state, const char* restrict data);
/**
* Gets the number of bytes the `libkeccak_state_t` stored
* at the beginning of `data` occupies
*
* @param data The data buffer
* @return The byte size of the stored state
*/
__attribute__((leaf, nonnull, nothrow, warn_unused_result, pure))
size_t libkeccak_state_unmarshal_skip(const char* restrict data);
#endif
