providers/implementations/macs/kmac_prov.c - third_party/openssl - Git at Google

 /*
  * Copyright 2018-2021 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"
 #include "internal/cryptlib.h" /* ossl_assert */

 /*
  * 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 */

 /*
  * Length encoding will be  a 1 byte size + length in bits (3 bytes max)
  * This gives a range of 0..0XFFFFFF bits = 2097151 bytes).
  */
 #define KMAC_MAX_OUTPUT_LEN (0xFFFFFF / 8)
 #define KMAC_MAX_ENCODED_HEADER_LEN (1 + 3)

 /*
  * Restrict the maximum length of the customisation string.  This must not
  * exceed 64 bits = 8k bytes.
  */
 #define KMAC_MAX_CUSTOM 256

 /* Maximum size of encoded custom string */
 #define KMAC_MAX_CUSTOM_ENCODED (KMAC_MAX_CUSTOM + KMAC_MAX_ENCODED_HEADER_LEN)

 /* Maximum key size in bytes = 256 (2048 bits) */
 #define KMAC_MAX_KEY 256
 #define KMAC_MIN_KEY 4

 /*
  * Maximum Encoded Key size will be padded to a multiple of the blocksize
  * i.e KMAC_MAX_KEY + KMAC_MAX_ENCODED_HEADER_LEN = 256 + 4
  * 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;
     size_t key_len;
     size_t 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, size_t out_max_len, size_t *out_len,
                          const unsigned char *in, size_t in_len);
 static int right_encode(unsigned char *out, size_t out_max_len, size_t *out_len,
                         size_t bits);
 static int bytepad(unsigned char *out, size_t *out_len,
                    const unsigned char *in1, size_t in1_len,
                    const unsigned char *in2, size_t in2_len,
                    size_t w);
 static int kmac_bytepad_encode_key(unsigned char *out, size_t out_max_len,
                                    size_t *out_len,
                                    const unsigned char *in, size_t in_len,
                                    size_t 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_get_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 int kmac_setkey(struct kmac_data_st *kctx, const unsigned char *key,
                        size_t keylen)
 {
     const EVP_MD *digest = ossl_prov_digest_md(&kctx->digest);
     int w = EVP_MD_get_block_size(digest);

     if (keylen < KMAC_MIN_KEY || keylen > KMAC_MAX_KEY) {
         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
         return 0;
     }
     if (w < 0) {
         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_DIGEST_LENGTH);
         return 0;
     }
     if (!kmac_bytepad_encode_key(kctx->key, sizeof(kctx->key), &kctx->key_len,
                                  key, keylen, (size_t)w))
         return 0;
     return 1;
 }

 /*
  * 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, const unsigned char *key,
                      size_t keylen, const OSSL_PARAM params[])
 {
     struct kmac_data_st *kctx = vmacctx;
     EVP_MD_CTX *ctx = kctx->ctx;
     unsigned char *out;
     size_t out_len, block_len;
     int res, t;

     if (!ossl_prov_is_running() || !kmac_set_ctx_params(kctx, params))
         return 0;

     if (key != NULL) {
         if (!kmac_setkey(kctx, key, keylen))
             return 0;
     } else if (kctx->key_len == 0) {
         /* Check key has been set */
         ERR_raise(ERR_LIB_PROV, PROV_R_NO_KEY_SET);
         return 0;
     }
     if (!EVP_DigestInit_ex(kctx->ctx, ossl_prov_digest_md(&kctx->digest),
                            NULL))
         return 0;

     t = EVP_MD_get_block_size(ossl_prov_digest_md(&kctx->digest));
     if (t < 0) {
         ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_DIGEST_LENGTH);
         return 0;
     }
     block_len = t;

     /* Set default custom string if it is not already set */
     if (kctx->custom_len == 0) {
         const OSSL_PARAM cparams[] = {
             OSSL_PARAM_octet_string(OSSL_MAC_PARAM_CUSTOM, "", 0),
             OSSL_PARAM_END
         };
         (void)kmac_set_ctx_params(kctx, cparams);
     }

     if (!bytepad(NULL, &out_len, kmac_string, sizeof(kmac_string),
                  kctx->custom, kctx->custom_len, block_len)) {
         ERR_raise(ERR_LIB_PROV, ERR_R_INTERNAL_ERROR);
         return 0;
     }
     out = OPENSSL_malloc(out_len);
     if (out == NULL) {
         ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
         return 0;
     }
     res = bytepad(out, NULL, 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);
     OPENSSL_free(out);
     return res;
 }

 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;
     size_t lbits, len;
     unsigned char encoded_outlen[KMAC_MAX_ENCODED_HEADER_LEN];
     int ok;

     if (!ossl_prov_is_running())
         return 0;

     /* KMAC XOF mode sets the encoded length to 0 */
     lbits = (kctx->xof_mode ? 0 : (kctx->out_len * 8));

     ok = right_encode(encoded_outlen, sizeof(encoded_outlen), &len, lbits)
         && EVP_DigestUpdate(ctx, encoded_outlen, len)
         && EVP_DigestFinalXOF(ctx, out, kctx->out_len);
     *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_size_t(OSSL_MAC_PARAM_BLOCK_SIZE, NULL),
     OSSL_PARAM_END
 };
 static const OSSL_PARAM *kmac_gettable_ctx_params(ossl_unused void *ctx,
                                                   ossl_unused void *provctx)
 {
     return known_gettable_ctx_params;
 }

 static int kmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
 {
     struct kmac_data_st *kctx = vmacctx;
     OSSL_PARAM *p;
     int sz;

     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL
             && !OSSL_PARAM_set_size_t(p, kctx->out_len))
         return 0;

     if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_BLOCK_SIZE)) != NULL) {
         sz = EVP_MD_block_size(ossl_prov_digest_md(&kctx->digest));
         if (!OSSL_PARAM_set_int(p, sz))
             return 0;
     }

     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(ossl_unused void *ctx,
                                                   ossl_unused void *provctx)
 {
     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;

     if (params == NULL)
         return 1;

     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) {
         size_t sz = 0;

         if (!OSSL_PARAM_get_size_t(p, &sz))
             return 0;
         if (sz > KMAC_MAX_OUTPUT_LEN) {
             ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_OUTPUT_LENGTH);
             return 0;
         }
         kctx->out_len = sz;
     }
     if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL
             && !kmac_setkey(kctx, p->data, p->data_size))
         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, sizeof(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, size_t out_max_len, size_t *out_len,
                         size_t bits)
 {
     unsigned int len = get_encode_size(bits);
     int i;

     if (len >= out_max_len) {
         ERR_raise(ERR_LIB_PROV, PROV_R_LENGTH_TOO_LARGE);
         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, size_t out_max_len, size_t *out_len,
                          const unsigned char *in, size_t in_len)
 {
     if (in == NULL) {
         *out_len = 0;
     } else {
         size_t i, bits, len, sz;

         bits = 8 * in_len;
         len = get_encode_size(bits);
         sz = 1 + len + in_len;

         if (sz > out_max_len) {
             ERR_raise(ERR_LIB_PROV, PROV_R_LENGTH_TOO_LARGE);
             return 0;
         }

         out[0] = (unsigned char)len;
         for (i = len; i > 0; --i) {
             out[i] = (bits & 0xFF);
             bits >>= 8;
         }
         memcpy(out + len + 1, in, in_len);
         *out_len = sz;
     }
     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, size_t *out_len,
                    const unsigned char *in1, size_t in1_len,
                    const unsigned char *in2, size_t in2_len, size_t w)
 {
     int len;
     unsigned char *p = out;
     int sz = w;

     if (out == NULL) {
         if (out_len == NULL) {
             ERR_raise(ERR_LIB_PROV, ERR_R_PASSED_NULL_PARAMETER);
             return 0;
         }
         sz = 2 + in1_len + (in2 != NULL ? in2_len : 0);
         *out_len = (sz + w - 1) / w * w;
         return 1;
     }

     if (!ossl_assert(w <= 255))
         return 0;

     /* Left encoded w */
     *p++ = 1;
     *p++ = (unsigned char)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;
     sz = (len + w - 1) / w * w;
     /* zero pad the end of the buffer */
     if (sz != len)
         memset(p, 0, sz - len);
     if (out_len != NULL)
         *out_len = sz;
     return 1;
 }

 /* Returns out = bytepad(encode_string(in), w) */
 static int kmac_bytepad_encode_key(unsigned char *out, size_t out_max_len,
                                    size_t *out_len,
                                    const unsigned char *in, size_t in_len,
                                    size_t w)
 {
     unsigned char tmp[KMAC_MAX_KEY + KMAC_MAX_ENCODED_HEADER_LEN];
     size_t tmp_len;

     if (!encode_string(tmp, sizeof(tmp), &tmp_len, in, in_len))
         return 0;
     if (!bytepad(NULL, out_len, tmp, tmp_len, NULL, 0, w))
         return 0;
     if (!ossl_assert(*out_len <= out_max_len))
         return 0;
     return bytepad(out, NULL, tmp, tmp_len, NULL, 0, w);
 }

 const OSSL_DISPATCH ossl_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 ossl_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 }
 };
	/*
	* Copyright 2018-2021 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"
	#include "internal/cryptlib.h" /* ossl_assert */

	/*
	* 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 */

	/*
	* Length encoding will be a 1 byte size + length in bits (3 bytes max)
	* This gives a range of 0..0XFFFFFF bits = 2097151 bytes).
	*/
	#define KMAC_MAX_OUTPUT_LEN (0xFFFFFF / 8)
	#define KMAC_MAX_ENCODED_HEADER_LEN (1 + 3)

	/*
	* Restrict the maximum length of the customisation string. This must not
	* exceed 64 bits = 8k bytes.
	*/
	#define KMAC_MAX_CUSTOM 256

	/* Maximum size of encoded custom string */
	#define KMAC_MAX_CUSTOM_ENCODED (KMAC_MAX_CUSTOM + KMAC_MAX_ENCODED_HEADER_LEN)

	/* Maximum key size in bytes = 256 (2048 bits) */
	#define KMAC_MAX_KEY 256
	#define KMAC_MIN_KEY 4

	/*
	* Maximum Encoded Key size will be padded to a multiple of the blocksize
	* i.e KMAC_MAX_KEY + KMAC_MAX_ENCODED_HEADER_LEN = 256 + 4
	* 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;
	size_t key_len;
	size_t 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, size_t out_max_len, size_t out_len,
	const unsigned char *in, size_t in_len);
	static int right_encode(unsigned char out, size_t out_max_len, size_t out_len,
	size_t bits);
	static int bytepad(unsigned char out, size_t out_len,
	const unsigned char *in1, size_t in1_len,
	const unsigned char *in2, size_t in2_len,
	size_t w);
	static int kmac_bytepad_encode_key(unsigned char *out, size_t out_max_len,
	size_t *out_len,
	const unsigned char *in, size_t in_len,
	size_t 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_get_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 int kmac_setkey(struct kmac_data_st kctx, const unsigned char key,
	size_t keylen)
	{
	const EVP_MD *digest = ossl_prov_digest_md(&kctx->digest);
	int w = EVP_MD_get_block_size(digest);

	if (keylen < KMAC_MIN_KEY \|\| keylen > KMAC_MAX_KEY) {
	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);
	return 0;
	}
	if (w < 0) {
	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_DIGEST_LENGTH);
	return 0;
	}
	if (!kmac_bytepad_encode_key(kctx->key, sizeof(kctx->key), &kctx->key_len,
	key, keylen, (size_t)w))
	return 0;
	return 1;
	}

	/*
	* 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, const unsigned char key,
	size_t keylen, const OSSL_PARAM params[])
	{
	struct kmac_data_st *kctx = vmacctx;
	EVP_MD_CTX *ctx = kctx->ctx;
	unsigned char *out;
	size_t out_len, block_len;
	int res, t;

	if (!ossl_prov_is_running() \|\| !kmac_set_ctx_params(kctx, params))
	return 0;

	if (key != NULL) {
	if (!kmac_setkey(kctx, key, keylen))
	return 0;
	} else if (kctx->key_len == 0) {
	/* Check key has been set */
	ERR_raise(ERR_LIB_PROV, PROV_R_NO_KEY_SET);
	return 0;
	}
	if (!EVP_DigestInit_ex(kctx->ctx, ossl_prov_digest_md(&kctx->digest),
	NULL))
	return 0;

	t = EVP_MD_get_block_size(ossl_prov_digest_md(&kctx->digest));
	if (t < 0) {
	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_DIGEST_LENGTH);
	return 0;
	}
	block_len = t;

	/* Set default custom string if it is not already set */
	if (kctx->custom_len == 0) {
	const OSSL_PARAM cparams[] = {
	OSSL_PARAM_octet_string(OSSL_MAC_PARAM_CUSTOM, "", 0),
	OSSL_PARAM_END
	};
	(void)kmac_set_ctx_params(kctx, cparams);
	}

	if (!bytepad(NULL, &out_len, kmac_string, sizeof(kmac_string),
	kctx->custom, kctx->custom_len, block_len)) {
	ERR_raise(ERR_LIB_PROV, ERR_R_INTERNAL_ERROR);
	return 0;
	}
	out = OPENSSL_malloc(out_len);
	if (out == NULL) {
	ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);
	return 0;
	}
	res = bytepad(out, NULL, 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);
	OPENSSL_free(out);
	return res;
	}

	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;
	size_t lbits, len;
	unsigned char encoded_outlen[KMAC_MAX_ENCODED_HEADER_LEN];
	int ok;

	if (!ossl_prov_is_running())
	return 0;

	/* KMAC XOF mode sets the encoded length to 0 */
	lbits = (kctx->xof_mode ? 0 : (kctx->out_len * 8));

	ok = right_encode(encoded_outlen, sizeof(encoded_outlen), &len, lbits)
	&& EVP_DigestUpdate(ctx, encoded_outlen, len)
	&& EVP_DigestFinalXOF(ctx, out, kctx->out_len);
	*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_size_t(OSSL_MAC_PARAM_BLOCK_SIZE, NULL),
	OSSL_PARAM_END
	};
	static const OSSL_PARAM kmac_gettable_ctx_params(ossl_unused void ctx,
	ossl_unused void *provctx)
	{
	return known_gettable_ctx_params;
	}

	static int kmac_get_ctx_params(void *vmacctx, OSSL_PARAM params[])
	{
	struct kmac_data_st *kctx = vmacctx;
	OSSL_PARAM *p;
	int sz;

	if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_SIZE)) != NULL
	&& !OSSL_PARAM_set_size_t(p, kctx->out_len))
	return 0;

	if ((p = OSSL_PARAM_locate(params, OSSL_MAC_PARAM_BLOCK_SIZE)) != NULL) {
	sz = EVP_MD_block_size(ossl_prov_digest_md(&kctx->digest));
	if (!OSSL_PARAM_set_int(p, sz))
	return 0;
	}

	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(ossl_unused void ctx,
	ossl_unused void *provctx)
	{
	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;

	if (params == NULL)
	return 1;

	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) {
	size_t sz = 0;

	if (!OSSL_PARAM_get_size_t(p, &sz))
	return 0;
	if (sz > KMAC_MAX_OUTPUT_LEN) {
	ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_OUTPUT_LENGTH);
	return 0;
	}
	kctx->out_len = sz;
	}
	if ((p = OSSL_PARAM_locate_const(params, OSSL_MAC_PARAM_KEY)) != NULL
	&& !kmac_setkey(kctx, p->data, p->data_size))
	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, sizeof(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, size_t out_max_len, size_t out_len,
	size_t bits)
	{
	unsigned int len = get_encode_size(bits);
	int i;

	if (len >= out_max_len) {
	ERR_raise(ERR_LIB_PROV, PROV_R_LENGTH_TOO_LARGE);
	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, size_t out_max_len, size_t out_len,
	const unsigned char *in, size_t in_len)
	{
	if (in == NULL) {
	*out_len = 0;
	} else {
	size_t i, bits, len, sz;

	bits = 8 * in_len;
	len = get_encode_size(bits);
	sz = 1 + len + in_len;

	if (sz > out_max_len) {
	ERR_raise(ERR_LIB_PROV, PROV_R_LENGTH_TOO_LARGE);
	return 0;
	}

	out[0] = (unsigned char)len;
	for (i = len; i > 0; --i) {
	out[i] = (bits & 0xFF);
	bits >>= 8;
	}
	memcpy(out + len + 1, in, in_len);
	*out_len = sz;
	}
	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, size_t out_len,
	const unsigned char *in1, size_t in1_len,
	const unsigned char *in2, size_t in2_len, size_t w)
	{
	int len;
	unsigned char *p = out;
	int sz = w;

	if (out == NULL) {
	if (out_len == NULL) {
	ERR_raise(ERR_LIB_PROV, ERR_R_PASSED_NULL_PARAMETER);
	return 0;
	}
	sz = 2 + in1_len + (in2 != NULL ? in2_len : 0);
	out_len = (sz + w - 1) / w w;
	return 1;
	}

	if (!ossl_assert(w <= 255))
	return 0;

	/* Left encoded w */
	*p++ = 1;
	*p++ = (unsigned char)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;
	sz = (len + w - 1) / w * w;
	/* zero pad the end of the buffer */
	if (sz != len)
	memset(p, 0, sz - len);
	if (out_len != NULL)
	*out_len = sz;
	return 1;
	}

	/* Returns out = bytepad(encode_string(in), w) */
	static int kmac_bytepad_encode_key(unsigned char *out, size_t out_max_len,
	size_t *out_len,
	const unsigned char *in, size_t in_len,
	size_t w)
	{
	unsigned char tmp[KMAC_MAX_KEY + KMAC_MAX_ENCODED_HEADER_LEN];
	size_t tmp_len;

	if (!encode_string(tmp, sizeof(tmp), &tmp_len, in, in_len))
	return 0;
	if (!bytepad(NULL, out_len, tmp, tmp_len, NULL, 0, w))
	return 0;
	if (!ossl_assert(*out_len <= out_max_len))
	return 0;
	return bytepad(out, NULL, tmp, tmp_len, NULL, 0, w);
	}

	const OSSL_DISPATCH ossl_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 ossl_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 }
	};