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- /*
- * Copyright 2018 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_numbers.h>
- #include <openssl/core_names.h>
- #include <openssl/params.h>
- #include <openssl/evp.h>
- #include <openssl/err.h>
- #include "internal/providercommonerr.h"
- #include "internal/provider_algs.h"
- #include "internal/provider_ctx.h"
- #include "internal/provider_util.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_OP_mac_newctx_fn kmac128_new;
- static OSSL_OP_mac_newctx_fn kmac256_new;
- static OSSL_OP_mac_dupctx_fn kmac_dup;
- static OSSL_OP_mac_freectx_fn kmac_free;
- static OSSL_OP_mac_gettable_ctx_params_fn kmac_gettable_ctx_params;
- static OSSL_OP_mac_get_ctx_params_fn kmac_get_ctx_params;
- static OSSL_OP_mac_settable_ctx_params_fn kmac_settable_ctx_params;
- static OSSL_OP_mac_set_ctx_params_fn kmac_set_ctx_params;
- static OSSL_OP_mac_size_fn kmac_size;
- static OSSL_OP_mac_init_fn kmac_init;
- static OSSL_OP_mac_update_fn kmac_update;
- static OSSL_OP_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 ((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_LIBRARY_CONTEXT_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 = 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;
- }
- /*
- * 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;
- /* Check key has been set */
- if (kctx->key_len == 0) {
- EVPerr(EVP_F_KMAC_INIT, 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(ossl_prov_digest_md(&kctx->digest));
- /* Set default custom string if it is not already set */
- if (kctx->custom_len == 0) {
- const OSSL_PARAM params[] = {
- OSSL_PARAM_octet_string(OSSL_MAC_PARAM_CUSTOM, "", 0),
- OSSL_PARAM_END
- };
- (void)kmac_set_ctx_params(kctx, params);
- }
- return bytepad(out, &out_len, kmac_string, sizeof(kmac_string),
- kctx->custom, kctx->custom_len, block_len)
- && EVP_DigestUpdate(ctx, out, out_len)
- && EVP_DigestUpdate(ctx, kctx->key, kctx->key_len);
- }
- static size_t kmac_size(void *vmacctx)
- {
- struct kmac_data_st *kctx = vmacctx;
- return kctx->out_len;
- }
- static int kmac_update(void *vmacctx, const unsigned char *data,
- size_t datalen)
- {
- struct kmac_data_st *kctx = vmacctx;
- return EVP_DigestUpdate(kctx->ctx, data, datalen);
- }
- static int kmac_final(void *vmacctx, unsigned char *out, size_t *outl,
- size_t outsize)
- {
- struct kmac_data_st *kctx = vmacctx;
- EVP_MD_CTX *ctx = kctx->ctx;
- int lbits, len;
- unsigned char encoded_outlen[KMAC_MAX_ENCODED_HEADER_LEN];
- int ok;
- /* KMAC XOF mode sets the encoded length to 0 */
- lbits = (kctx->xof_mode ? 0 : (kctx->out_len * 8));
- ok = right_encode(encoded_outlen, &len, lbits)
- && EVP_DigestUpdate(ctx, encoded_outlen, len)
- && EVP_DigestFinalXOF(ctx, out, kctx->out_len);
- if (ok && outl != NULL)
- *outl = kctx->out_len;
- return ok;
- }
- static const OSSL_PARAM known_gettable_ctx_params[] = {
- OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
- OSSL_PARAM_END
- };
- static const OSSL_PARAM *kmac_gettable_ctx_params(void)
- {
- return known_gettable_ctx_params;
- }
- static int kmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
- {
- OSSL_PARAM *p;
- if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL)
- return OSSL_PARAM_set_size_t(p, kmac_size(vmacctx));
- return 1;
- }
- static const OSSL_PARAM known_settable_ctx_params[] = {
- OSSL_PARAM_int(OSSL_MAC_PARAM_XOF, NULL),
- OSSL_PARAM_size_t(OSSL_MAC_PARAM_SIZE, NULL),
- OSSL_PARAM_octet_string(OSSL_MAC_PARAM_KEY, NULL, 0),
- OSSL_PARAM_octet_string(OSSL_MAC_PARAM_CUSTOM, NULL, 0),
- OSSL_PARAM_END
- };
- static const OSSL_PARAM *kmac_settable_ctx_params(void)
- {
- return known_settable_ctx_params;
- }
- /*
- * The following params can be set any time before final():
- * - "outlen" or "size": The requested output length.
- * - "xof": If set, this indicates that right_encoded(0)
- * is part of the digested data, otherwise it
- * uses right_encoded(requested output length).
- *
- * All other params should be set before init().
- */
- static int kmac_set_ctx_params(void *vmacctx, const OSSL_PARAM *params)
- {
- struct kmac_data_st *kctx = vmacctx;
- const OSSL_PARAM *p;
- const EVP_MD *digest = ossl_prov_digest_md(&kctx->digest);
- if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_XOF)) != NULL
- && !OSSL_PARAM_get_int(p, &kctx->xof_mode))
- return 0;
- if (((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_SIZE)) != NULL)
- && !OSSL_PARAM_get_size_t(p, &kctx->out_len))
- return 0;
- if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL) {
- if (p->data_size < 4 || p->data_size > KMAC_MAX_KEY) {
- ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
- return 0;
- }
- if (!kmac_bytepad_encode_key(kctx->key, &kctx->key_len,
- p->data, p->data_size,
- EVP_MD_block_size(digest)))
- return 0;
- }
- if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_CUSTOM))
- != NULL) {
- if (p->data_size > KMAC_MAX_CUSTOM) {
- ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_CUSTOM_LENGTH);
- return 0;
- }
- if (!encode_string(kctx->custom, &kctx->custom_len,
- p->data, p->data_size))
- return 0;
- }
- return 1;
- }
- /*
- * Encoding/Padding Methods.
- */
- /* Returns the number of bytes required to store 'bits' into a byte array */
- static unsigned int get_encode_size(size_t bits)
- {
- unsigned int cnt = 0, sz = sizeof(size_t);
- while (bits && (cnt < sz)) {
- ++cnt;
- bits >>= 8;
- }
- /* If bits is zero 1 byte is required */
- if (cnt == 0)
- cnt = 1;
- return cnt;
- }
- /*
- * Convert an integer into bytes . The number of bytes is appended
- * to the end of the buffer. Returns an array of bytes 'out' of size
- * *out_len.
- *
- * e.g if bits = 32, out[2] = { 0x20, 0x01 }
- *
- */
- static int right_encode(unsigned char *out, int *out_len, size_t bits)
- {
- unsigned int len = get_encode_size(bits);
- int i;
- /* The length is constrained to a single byte: 2040/8 = 255 */
- if (len > 0xFF)
- return 0;
- /* MSB's are at the start of the bytes array */
- for (i = len - 1; i >= 0; --i) {
- out[i] = (unsigned char)(bits & 0xFF);
- bits >>= 8;
- }
- /* Tack the length onto the end */
- out[len] = (unsigned char)len;
- /* The Returned length includes the tacked on byte */
- *out_len = len + 1;
- return 1;
- }
- /*
- * Encodes a string with a left encoded length added. Note that the
- * in_len is converted to bits (*8).
- *
- * e.g- in="KMAC" gives out[6] = { 0x01, 0x20, 0x4B, 0x4D, 0x41, 0x43 }
- * len bits K M A C
- */
- static int encode_string(unsigned char *out, int *out_len,
- const unsigned char *in, int in_len)
- {
- if (in == NULL) {
- *out_len = 0;
- } else {
- int i, bits, len;
- bits = 8 * in_len;
- len = get_encode_size(bits);
- if (len > 0xFF)
- return 0;
- out[0] = len;
- for (i = len; i > 0; --i) {
- out[i] = (bits & 0xFF);
- bits >>= 8;
- }
- memcpy(out + len + 1, in, in_len);
- *out_len = (1 + len + in_len);
- }
- return 1;
- }
- /*
- * Returns a zero padded encoding of the inputs in1 and an optional
- * in2 (can be NULL). The padded output must be a multiple of the blocksize 'w'.
- * The value of w is in bytes (< 256).
- *
- * The returned output is:
- * zero_padded(multiple of w, (left_encode(w) || in1 [|| in2])
- */
- 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)
- {
- int len;
- unsigned char *p = out;
- int sz = w;
- /* Left encoded w */
- *p++ = 1;
- *p++ = w;
- /* || in1 */
- memcpy(p, in1, in1_len);
- p += in1_len;
- /* [ || in2 ] */
- if (in2 != NULL && in2_len > 0) {
- memcpy(p, in2, in2_len);
- p += in2_len;
- }
- /* Figure out the pad size (divisible by w) */
- len = p - out;
- while (len > sz) {
- sz += w;
- }
- /* zero pad the end of the buffer */
- memset(p, 0, sz - len);
- *out_len = sz;
- return 1;
- }
- /*
- * Returns out = bytepad(encode_string(in), w)
- */
- static int kmac_bytepad_encode_key(unsigned char *out, int *out_len,
- const unsigned char *in, int in_len,
- int w)
- {
- unsigned char tmp[KMAC_MAX_KEY + KMAC_MAX_ENCODED_HEADER_LEN];
- int tmp_len;
- if (!encode_string(tmp, &tmp_len, in, in_len))
- return 0;
- return bytepad(out, out_len, tmp, tmp_len, NULL, 0, w);
- }
- const OSSL_DISPATCH kmac128_functions[] = {
- { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))kmac128_new },
- { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))kmac_dup },
- { OSSL_FUNC_MAC_FREECTX, (void (*)(void))kmac_free },
- { OSSL_FUNC_MAC_INIT, (void (*)(void))kmac_init },
- { OSSL_FUNC_MAC_UPDATE, (void (*)(void))kmac_update },
- { OSSL_FUNC_MAC_FINAL, (void (*)(void))kmac_final },
- { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
- (void (*)(void))kmac_gettable_ctx_params },
- { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))kmac_get_ctx_params },
- { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
- (void (*)(void))kmac_settable_ctx_params },
- { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))kmac_set_ctx_params },
- { 0, NULL }
- };
- const OSSL_DISPATCH kmac256_functions[] = {
- { OSSL_FUNC_MAC_NEWCTX, (void (*)(void))kmac256_new },
- { OSSL_FUNC_MAC_DUPCTX, (void (*)(void))kmac_dup },
- { OSSL_FUNC_MAC_FREECTX, (void (*)(void))kmac_free },
- { OSSL_FUNC_MAC_INIT, (void (*)(void))kmac_init },
- { OSSL_FUNC_MAC_UPDATE, (void (*)(void))kmac_update },
- { OSSL_FUNC_MAC_FINAL, (void (*)(void))kmac_final },
- { OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS,
- (void (*)(void))kmac_gettable_ctx_params },
- { OSSL_FUNC_MAC_GET_CTX_PARAMS, (void (*)(void))kmac_get_ctx_params },
- { OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS,
- (void (*)(void))kmac_settable_ctx_params },
- { OSSL_FUNC_MAC_SET_CTX_PARAMS, (void (*)(void))kmac_set_ctx_params },
- { 0, NULL }
- };
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