/*

 * Copyright 1999-2021 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/pkcs12.h>

#include <openssl/bn.h>

/* Uncomment out this line to get debugging info about key generation */

/*

 * #define OPENSSL_DEBUG_KEYGEN

 */

#ifdef OPENSSL_DEBUG_KEYGEN

# include <openssl/bio.h>

extern BIO *bio_err;

void h__dump(unsigned char *p, int len);

#endif

/* PKCS12 compatible key/IV generation */

#ifndef min

# define min(a,b) ((a) < (b) ? (a) : (b))

#endif

int PKCS12_key_gen_asc(const char *pass, int passlen, unsigned char *salt,

                       int saltlen, int id, int iter, int n,

                       unsigned char *out, const EVP_MD *md_type)

{

    int ret;

    unsigned char *unipass;

    int uniplen;

    if (!pass) {

        unipass = NULL;

        uniplen = 0;

    } else if (!OPENSSL_asc2uni(pass, passlen, &unipass, &uniplen)) {

        PKCS12err(PKCS12_F_PKCS12_KEY_GEN_ASC, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    ret = PKCS12_key_gen_uni(unipass, uniplen, salt, saltlen,

                             id, iter, n, out, md_type);

    if (ret <= 0)

        return 0;

    OPENSSL_clear_free(unipass, uniplen);

    return ret;

}

int PKCS12_key_gen_utf8(const char *pass, int passlen, unsigned char *salt,

                        int saltlen, int id, int iter, int n,

                        unsigned char *out, const EVP_MD *md_type)

{

    int ret;

    unsigned char *unipass;

    int uniplen;

    if (!pass) {

        unipass = NULL;

        uniplen = 0;

    } else if (!OPENSSL_utf82uni(pass, passlen, &unipass, &uniplen)) {

        PKCS12err(PKCS12_F_PKCS12_KEY_GEN_UTF8, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    ret = PKCS12_key_gen_uni(unipass, uniplen, salt, saltlen,

                             id, iter, n, out, md_type);

    if (ret <= 0)

        return 0;

    OPENSSL_clear_free(unipass, uniplen);

    return ret;

}

int PKCS12_key_gen_uni(unsigned char *pass, int passlen, unsigned char *salt,

                       int saltlen, int id, int iter, int n,

                       unsigned char *out, const EVP_MD *md_type)

{

    unsigned char *B = NULL, *D = NULL, *I = NULL, *p = NULL, *Ai = NULL;

    int Slen, Plen, Ilen;

    int i, j, u, v;

    int ret = 0;

    EVP_MD_CTX *ctx = NULL;

#ifdef  OPENSSL_DEBUG_KEYGEN

    unsigned char *tmpout = out;

    int tmpn = n;

#endif

    ctx = EVP_MD_CTX_new();

    if (ctx == NULL)

        goto err;

#ifdef  OPENSSL_DEBUG_KEYGEN

    fprintf(stderr, "KEYGEN DEBUG\n");

    fprintf(stderr, "ID %d, ITER %d\n", id, iter);

    fprintf(stderr, "Password (length %d):\n", passlen);

    h__dump(pass, passlen);

    fprintf(stderr, "Salt (length %d):\n", saltlen);

    h__dump(salt, saltlen);

#endif

    v = EVP_MD_block_size(md_type);

    u = EVP_MD_size(md_type);

    if (u <= 0 || v <= 0)

        goto err;

    D = OPENSSL_malloc(v);

    Ai = OPENSSL_malloc(u);

    B = OPENSSL_malloc(v + 1);

    Slen = v * ((saltlen + v - 1) / v);

    if (passlen)

        Plen = v * ((passlen + v - 1) / v);

    else

        Plen = 0;

    Ilen = Slen + Plen;

    I = OPENSSL_malloc(Ilen);

    if (D == NULL || Ai == NULL || B == NULL || I == NULL)

        goto err;

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

        D[i] = id;

    p = I;

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

        *p++ = salt[i % saltlen];

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

        *p++ = pass[i % passlen];

    for (;;) {

        if (!EVP_DigestInit_ex(ctx, md_type, NULL)

            || !EVP_DigestUpdate(ctx, D, v)

            || !EVP_DigestUpdate(ctx, I, Ilen)

            || !EVP_DigestFinal_ex(ctx, Ai, NULL))

            goto err;

        for (j = 1; j < iter; j++) {

            if (!EVP_DigestInit_ex(ctx, md_type, NULL)

                || !EVP_DigestUpdate(ctx, Ai, u)

                || !EVP_DigestFinal_ex(ctx, Ai, NULL))

                goto err;

        }

        memcpy(out, Ai, min(n, u));

        if (u >= n) {

#ifdef OPENSSL_DEBUG_KEYGEN

            fprintf(stderr, "Output KEY (length %d)\n", tmpn);

            h__dump(tmpout, tmpn);

#endif

            ret = 1;

            goto end;

        }

        n -= u;

        out += u;

        for (j = 0; j < v; j++)

            B[j] = Ai[j % u];

        for (j = 0; j < Ilen; j += v) {

            int k;

            unsigned char *Ij = I + j;

            uint16_t c = 1;

            /* Work out Ij = Ij + B + 1 */

            for (k = v - 1; k >= 0; k--) {

                c += Ij[k] + B[k];

                Ij[k] = (unsigned char)c;

                c >>= 8;

            }

        }

    }

 err:

    PKCS12err(PKCS12_F_PKCS12_KEY_GEN_UNI, ERR_R_MALLOC_FAILURE);

 end:

    OPENSSL_free(Ai);

    OPENSSL_free(B);

    OPENSSL_free(D);

    OPENSSL_free(I);

    EVP_MD_CTX_free(ctx);

    return ret;

}

#ifdef OPENSSL_DEBUG_KEYGEN

void h__dump(unsigned char *p, int len)

{

    for (; len--; p++)

        fprintf(stderr, "%02X", *p);

    fprintf(stderr, "\n");

}

#endif