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/*
* Copyright 2018-2020 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
/*
* See SP800-185 "Appendix A - KMAC, .... in Terms of Keccak[c]"
*
* Inputs are:
* K = Key (len(K) < 2^2040 bits)
* X = Input
* L = Output length (0 <= L < 2^2040 bits)
* S = Customization String Default="" (len(S) < 2^2040 bits)
*
* KMAC128(K, X, L, S)
* {
* newX = bytepad(encode_string(K), 168) || X || right_encode(L).
* T = bytepad(encode_string("KMAC") || encode_string(S), 168).
* return KECCAK[256](T || newX || 00, L).
* }
*
* KMAC256(K, X, L, S)
* {
* newX = bytepad(encode_string(K), 136) || X || right_encode(L).
* T = bytepad(encode_string("KMAC") || encode_string(S), 136).
* return KECCAK[512](T || newX || 00, L).
* }
*
* KMAC128XOF(K, X, L, S)
* {
* newX = bytepad(encode_string(K), 168) || X || right_encode(0).
* T = bytepad(encode_string("KMAC") || encode_string(S), 168).
* return KECCAK[256](T || newX || 00, L).
* }
*
* KMAC256XOF(K, X, L, S)
* {
* newX = bytepad(encode_string(K), 136) || X || right_encode(0).
* T = bytepad(encode_string("KMAC") || encode_string(S), 136).
* return KECCAK[512](T || newX || 00, L).
* }
*
*/
#include <stdlib.h>
#include <string.h>
#include <openssl/core_dispatch.h>
#include <openssl/core_names.h>
#include <openssl/params.h>
#include <openssl/evp.h>
#include <openssl/err.h>
#include <openssl/proverr.h>
#include "prov/implementations.h"
#include "prov/provider_ctx.h"
#include "prov/provider_util.h"
#include "prov/providercommon.h"
/*
* Forward declaration of everything implemented here. This is not strictly
* necessary for the compiler, but provides an assurance that the signatures
* of the functions in the dispatch table are correct.
*/
static OSSL_FUNC_mac_newctx_fn kmac128_new;
static OSSL_FUNC_mac_newctx_fn kmac256_new;
static OSSL_FUNC_mac_dupctx_fn kmac_dup;
static OSSL_FUNC_mac_freectx_fn kmac_free;
static OSSL_FUNC_mac_gettable_ctx_params_fn kmac_gettable_ctx_params;
static OSSL_FUNC_mac_get_ctx_params_fn kmac_get_ctx_params;
static OSSL_FUNC_mac_settable_ctx_params_fn kmac_settable_ctx_params;
static OSSL_FUNC_mac_set_ctx_params_fn kmac_set_ctx_params;
static OSSL_FUNC_mac_init_fn kmac_init;
static OSSL_FUNC_mac_update_fn kmac_update;
static OSSL_FUNC_mac_final_fn kmac_final;
#define KMAC_MAX_BLOCKSIZE ((1600 - 128*2) / 8) /* 168 */
#define KMAC_MIN_BLOCKSIZE ((1600 - 256*2) / 8) /* 136 */
/* Length encoding will be a 1 byte size + length in bits (2 bytes max) */
#define KMAC_MAX_ENCODED_HEADER_LEN 3
/*
* Custom string max size is chosen such that:
* len(encoded_string(custom) + len(kmac_encoded_string) <= KMAC_MIN_BLOCKSIZE
* i.e: (KMAC_MAX_CUSTOM + KMAC_MAX_ENCODED_LEN) + 6 <= 136
*/
#define KMAC_MAX_CUSTOM 127
/* Maximum size of encoded custom string */
#define KMAC_MAX_CUSTOM_ENCODED (KMAC_MAX_CUSTOM + KMAC_MAX_ENCODED_HEADER_LEN)
/* Maximum key size in bytes = 2040 / 8 */
#define KMAC_MAX_KEY 255
/*
* Maximum Encoded Key size will be padded to a multiple of the blocksize
* i.e KMAC_MAX_KEY + KMAC_MAX_ENCODED_LEN = 258
* Padded to a multiple of KMAC_MAX_BLOCKSIZE
*/
#define KMAC_MAX_KEY_ENCODED (KMAC_MAX_BLOCKSIZE * 2)
/* Fixed value of encode_string("KMAC") */
static const unsigned char kmac_string[] = {
0x01, 0x20, 0x4B, 0x4D, 0x41, 0x43
};
#define KMAC_FLAG_XOF_MODE 1
struct kmac_data_st {
void *provctx;
EVP_MD_CTX *ctx;
PROV_DIGEST digest;
size_t out_len;
int key_len;
int custom_len;
/* If xof_mode = 1 then we use right_encode(0) */
int xof_mode;
/* key and custom are stored in encoded form */
unsigned char key[KMAC_MAX_KEY_ENCODED];
unsigned char custom[KMAC_MAX_CUSTOM_ENCODED];
};
static int encode_string(unsigned char *out, int *out_len,
const unsigned char *in, int in_len);
static int right_encode(unsigned char *out, int *out_len, size_t bits);
static int bytepad(unsigned char *out, int *out_len,
const unsigned char *in1, int in1_len,
const unsigned char *in2, int in2_len,
int w);
static int kmac_bytepad_encode_key(unsigned char *out, int *out_len,
const unsigned char *in, int in_len,
int w);
static void kmac_free(void *vmacctx)
{
struct kmac_data_st *kctx = vmacctx;
if (kctx != NULL) {
EVP_MD_CTX_free(kctx->ctx);
ossl_prov_digest_reset(&kctx->digest);
OPENSSL_cleanse(kctx->key, kctx->key_len);
OPENSSL_cleanse(kctx->custom, kctx->custom_len);
OPENSSL_free(kctx);
}
}
/*
* We have KMAC implemented as a hash, which we can use instead of
* reimplementing the EVP functionality with direct use of
* keccak_mac_init() and friends.
*/
static struct kmac_data_st *kmac_new(void *provctx)
{
struct kmac_data_st *kctx;
if (!ossl_prov_is_running())
return NULL;
if ((kctx = OPENSSL_zalloc(sizeof(*kctx))) == NULL
|| (kctx->ctx = EVP_MD_CTX_new()) == NULL) {
kmac_free(kctx);
return NULL;
}
kctx->provctx = provctx;
return kctx;
}
static void *kmac_fetch_new(void *provctx, const OSSL_PARAM *params)
{
struct kmac_data_st *kctx = kmac_new(provctx);
if (kctx == NULL)
return 0;
if (!ossl_prov_digest_load_from_params(&kctx->digest, params,
PROV_LIBCTX_OF(provctx))) {
kmac_free(kctx);
return 0;
}
kctx->out_len = EVP_MD_size(ossl_prov_digest_md(&kctx->digest));
return kctx;
}
static void *kmac128_new(void *provctx)
{
static const OSSL_PARAM kmac128_params[] = {
OSSL_PARAM_utf8_string("digest", OSSL_DIGEST_NAME_KECCAK_KMAC128,
sizeof(OSSL_DIGEST_NAME_KECCAK_KMAC128)),
OSSL_PARAM_END
};
return kmac_fetch_new(provctx, kmac128_params);
}
static void *kmac256_new(void *provctx)
{
static const OSSL_PARAM kmac256_params[] = {
OSSL_PARAM_utf8_string("digest", OSSL_DIGEST_NAME_KECCAK_KMAC256,
sizeof(OSSL_DIGEST_NAME_KECCAK_KMAC256)),
OSSL_PARAM_END
};
return kmac_fetch_new(provctx, kmac256_params);
}
static void *kmac_dup(void *vsrc)
{
struct kmac_data_st *src = vsrc;
struct kmac_data_st *dst;
if (!ossl_prov_is_running())
return NULL;
dst = kmac_new(src->provctx);
if (dst == NULL)
return NULL;
if (!EVP_MD_CTX_copy(dst->ctx, src->ctx)
|| !ossl_prov_digest_copy(&dst->digest, &src->digest)) {
kmac_free(dst);
return NULL;
}
dst->out_len = src->out_len;
dst->key_len = src->key_len;
dst->custom_len = src->custom_len;
dst->xof_mode = src->xof_mode;
memcpy(dst->key, src->key, src->key_len);
memcpy(dst->custom, src->custom, dst->custom_len);
return dst;
}
static size_t kmac_size(void *vmacctx)
{
struct kmac_data_st *kctx = vmacctx;
return kctx->out_len;
}
/*
* The init() assumes that any ctrl methods are set beforehand for
* md, key and custom. Setting the fields afterwards will have no
* effect on the output mac.
*/
static int kmac_init(void *vmacctx)
{
struct kmac_data_st *kctx = vmacctx;
EVP_MD_CTX *ctx = kctx->ctx;
unsigned char out[KMAC_MAX_BLOCKSIZE];
int out_len, block_len;
if (!ossl_prov_is_running())
return 0;
/* Check key has been set */
if (kctx->key_len == 0) {
ERR_raise(ERR_LIB_EVP, EVP_R_NO_KEY_SET);
return 0;
}
if (!EVP_DigestInit_ex(kctx->ctx, ossl_prov_digest_md(&kctx->digest),
NULL))
return 0;
block_len = EVP_MD_block_size(o
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