/*

 * Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (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

 */

#include <stdio.h>

#include "internal/cryptlib.h"

#include <openssl/kdf.h>

#include <openssl/evp.h>

#include "crypto/evp.h"

static int tls1_prf_alg(const EVP_MD *md,

                        const unsigned char *sec, size_t slen,

                        const unsigned char *seed, size_t seed_len,

                        unsigned char *out, size_t olen);

#define TLS1_PRF_MAXBUF 1024

/* TLS KDF pkey context structure */

typedef struct {

    /* Digest to use for PRF */

    const EVP_MD *md;

    /* Secret value to use for PRF */

    unsigned char *sec;

    size_t seclen;

    /* Buffer of concatenated seed data */

    unsigned char seed[TLS1_PRF_MAXBUF];

    size_t seedlen;

} TLS1_PRF_PKEY_CTX;

static int pkey_tls1_prf_init(EVP_PKEY_CTX *ctx)

{

    TLS1_PRF_PKEY_CTX *kctx;

    if ((kctx = OPENSSL_zalloc(sizeof(*kctx))) == NULL) {

        KDFerr(KDF_F_PKEY_TLS1_PRF_INIT, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    ctx->data = kctx;

    return 1;

}

static void pkey_tls1_prf_cleanup(EVP_PKEY_CTX *ctx)

{

    TLS1_PRF_PKEY_CTX *kctx = ctx->data;

    OPENSSL_clear_free(kctx->sec, kctx->seclen);

    OPENSSL_cleanse(kctx->seed, kctx->seedlen);

    OPENSSL_free(kctx);

}

static int pkey_tls1_prf_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)

{

    TLS1_PRF_PKEY_CTX *kctx = ctx->data;

    switch (type) {

    case EVP_PKEY_CTRL_TLS_MD:

        kctx->md = p2;

        return 1;

    case EVP_PKEY_CTRL_TLS_SECRET:

        if (p1 < 0)

            return 0;

        if (kctx->sec != NULL)

            OPENSSL_clear_free(kctx->sec, kctx->seclen);

        OPENSSL_cleanse(kctx->seed, kctx->seedlen);

        kctx->seedlen = 0;

        kctx->sec = OPENSSL_memdup(p2, p1);

        if (kctx->sec == NULL)

            return 0;

        kctx->seclen  = p1;

        return 1;

    case EVP_PKEY_CTRL_TLS_SEED:

        if (p1 == 0 || p2 == NULL)

            return 1;

        if (p1 < 0 || p1 > (int)(TLS1_PRF_MAXBUF - kctx->seedlen))

            return 0;

        memcpy(kctx->seed + kctx->seedlen, p2, p1);

        kctx->seedlen += p1;

        return 1;

    default:

        return -2;

    }

}

static int pkey_tls1_prf_ctrl_str(EVP_PKEY_CTX *ctx,

                                  const char *type, const char *value)

{

    if (value == NULL) {

        KDFerr(KDF_F_PKEY_TLS1_PRF_CTRL_STR, KDF_R_VALUE_MISSING);

        return 0;

    }

    if (strcmp(type, "md") == 0) {

        TLS1_PRF_PKEY_CTX *kctx = ctx->data;

        const EVP_MD *md = EVP_get_digestbyname(value);

        if (md == NULL) {

            KDFerr(KDF_F_PKEY_TLS1_PRF_CTRL_STR, KDF_R_INVALID_DIGEST);

            return 0;

        }

        kctx->md = md;

        return 1;

    }

    if (strcmp(type, "secret") == 0)

        return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_TLS_SECRET, value);

    if (strcmp(type, "hexsecret") == 0)

        return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_TLS_SECRET, value);

    if (strcmp(type, "seed") == 0)

        return EVP_PKEY_CTX_str2ctrl(ctx, EVP_PKEY_CTRL_TLS_SEED, value);

    if (strcmp(type, "hexseed") == 0)

        return EVP_PKEY_CTX_hex2ctrl(ctx, EVP_PKEY_CTRL_TLS_SEED, value);

    KDFerr(KDF_F_PKEY_TLS1_PRF_CTRL_STR, KDF_R_UNKNOWN_PARAMETER_TYPE);

    return -2;

}

static int pkey_tls1_prf_derive(EVP_PKEY_CTX *ctx, unsigned char *key,

                                size_t *keylen)

{

    TLS1_PRF_PKEY_CTX *kctx = ctx->data;

    if (kctx->md == NULL) {

        KDFerr(KDF_F_PKEY_TLS1_PRF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);

        return 0;

    }

    if (kctx->sec == NULL) {

        KDFerr(KDF_F_PKEY_TLS1_PRF_DERIVE, KDF_R_MISSING_SECRET);

        return 0;

    }

    if (kctx->seedlen == 0) {

        KDFerr(KDF_F_PKEY_TLS1_PRF_DERIVE, KDF_R_MISSING_SEED);

        return 0;

    }

    return tls1_prf_alg(kctx->md, kctx->sec, kctx->seclen,

                        kctx->seed, kctx->seedlen,

                        key, *keylen);

}

const EVP_PKEY_METHOD tls1_prf_pkey_meth = {

    EVP_PKEY_TLS1_PRF,

    0,

    pkey_tls1_prf_init,

    0,

    pkey_tls1_prf_cleanup,

    0, 0,

    0, 0,

    0,

    0,

    0,

    0,

    0, 0,

    0, 0, 0, 0,

    0, 0,

    0, 0,

    0,

    pkey_tls1_prf_derive,

    pkey_tls1_prf_ctrl,

    pkey_tls1_prf_ctrl_str

};

static int tls1_prf_P_hash(const EVP_MD *md,

                           const unsigned char *sec, size_t sec_len,

                           const unsigned char *seed, size_t seed_len,

                           unsigned char *out, size_t olen)

{

    int chunk;

    EVP_MD_CTX *ctx = NULL, *ctx_tmp = NULL, *ctx_init = NULL;

    EVP_PKEY *mac_key = NULL;

    unsigned char A1[EVP_MAX_MD_SIZE];

    size_t A1_len;

    int ret = 0;

    chunk = EVP_MD_size(md);

    if (!ossl_assert(chunk > 0))

        goto err;

    ctx = EVP_MD_CTX_new();

    ctx_tmp = EVP_MD_CTX_new();

    ctx_init = EVP_MD_CTX_new();

    if (ctx == NULL || ctx_tmp == NULL || ctx_init == NULL)

        goto err;

    EVP_MD_CTX_set_flags(ctx_init, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);

    mac_key = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, sec, sec_len);

    if (mac_key == NULL)

        goto err;

    if (!EVP_DigestSignInit(ctx_init, NULL, md, NULL, mac_key))

        goto err;

    if (!EVP_MD_CTX_copy_ex(ctx, ctx_init))

        goto err;

    if (seed != NULL && !EVP_DigestSignUpdate(ctx, seed, seed_len))

        goto err;

    if (!EVP_DigestSignFinal(ctx, A1, &A1_len))

        goto err;

    for (;;) {

        /* Reinit mac contexts */

        if (!EVP_MD_CTX_copy_ex(ctx, ctx_init))

            goto err;

        if (!EVP_DigestSignUpdate(ctx, A1, A1_len))

            goto err;

        if (olen > (size_t)chunk && !EVP_MD_CTX_copy_ex(ctx_tmp, ctx))

            goto err;

        if (seed && !EVP_DigestSignUpdate(ctx, seed, seed_len))

            goto err;

        if (olen > (size_t)chunk) {

            size_t mac_len;

            if (!EVP_DigestSignFinal(ctx, out, &mac_len))

                goto err;

            out += mac_len;

            olen -= mac_len;

            /* calc the next A1 value */

            if (!EVP_DigestSignFinal(ctx_tmp, A1, &A1_len))

                goto err;

        } else {                /* last one */

            if (!EVP_DigestSignFinal(ctx, A1, &A1_len))

                goto err;

            memcpy(out, A1, olen);

            break;

        }

    }

    ret = 1;

 err:

    EVP_PKEY_free(mac_key);

    EVP_MD_CTX_free(ctx);

    EVP_MD_CTX_free(ctx_tmp);

    EVP_MD_CTX_free(ctx_init);

    OPENSSL_cleanse(A1, sizeof(A1));

    return ret;

}

static int tls1_prf_alg(const EVP_MD *md,

                        const unsigned char *sec, size_t slen,

                        const unsigned char *seed, size_t seed_len,

                        unsigned char *out, size_t olen)

{

    if (EVP_MD_type(md) == NID_md5_sha1) {

        size_t i;

        unsigned char *tmp;

        if (!tls1_prf_P_hash(EVP_md5(), sec, slen/2 + (slen & 1),

                         seed, seed_len, out, olen))

            return 0;

        if ((tmp = OPENSSL_malloc(olen)) == NULL) {

            KDFerr(KDF_F_TLS1_PRF_ALG, ERR_R_MALLOC_FAILURE);

            return 0;

        }

        if (!tls1_prf_P_hash(EVP_sha1(), sec + slen/2, slen/2 + (slen & 1),

                         seed, seed_len, tmp, olen)) {

            OPENSSL_clear_free(tmp, olen);

            return 0;

        }

        for (i = 0; i < olen; i++)

            out[i] ^= tmp[i];

        OPENSSL_clear_free(tmp, olen);

        return 1;

    }

    if (!tls1_prf_P_hash(md, sec, slen, seed, seed_len, out, olen))

        return 0;

    return 1;

}