/*

 * Copyright 2018-2023 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 512

/* Maximum size of encoded custom string */

#define KMAC_MAX_CUSTOM_ENCODED (KMAC_MAX_CUSTOM + KMAC_MAX_ENCODED_HEADER_LEN)

/* Maximum key size in bytes = 512 (4096 bits) */

#define KMAC_MAX_KEY 512

#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 = 512 + 4

 * Padded to a multiple of KMAC_MAX_BLOCKSIZE

 */

#define KMAC_MAX_KEY_ENCODED (KMAC_MAX_BLOCKSIZE * 4)

/* 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);

    int md_size;

    if (kctx == NULL)

        return 0;

    if (!ossl_prov_digest_load_from_params(&kctx->digest, params,

                                      PROV_LIBCTX_OF(provctx))) {

        kmac_free(kctx);

        return 0;

    }

    md_size = EVP_MD_get_size(ossl_prov_digest_md(&kctx->digest));

    if (md_size <= 0) {

        kmac_free(kctx);

        return 0;

    }

    kctx->out_len = (size_t)md_size;

    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)

        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 },

    OSSL_DISPATCH_END

};

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 },

    OSSL_DISPATCH_END

};