/*

 * Copyright 1999-2016 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 <stdlib.h>

#include "internal/cryptlib.h"

# include <openssl/x509.h>

# include <openssl/evp.h>

# include <openssl/hmac.h>

# include "evp_locl.h"

/* set this to print out info about the keygen algorithm */

/* #define OPENSSL_DEBUG_PKCS5V2 */

# ifdef OPENSSL_DEBUG_PKCS5V2

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

# endif

/*

 * This is an implementation of PKCS#5 v2.0 password based encryption key

 * derivation function PBKDF2. SHA1 version verified against test vectors

 * posted by Peter Gutmann to the PKCS-TNG mailing list.

 */

int PKCS5_PBKDF2_HMAC(const char *pass, int passlen,

                      const unsigned char *salt, int saltlen, int iter,

                      const EVP_MD *digest, int keylen, unsigned char *out)

{

    const char *empty = "";

    unsigned char digtmp[EVP_MAX_MD_SIZE], *p, itmp[4];

    int cplen, j, k, tkeylen, mdlen;

    unsigned long i = 1;

    HMAC_CTX *hctx_tpl = NULL, *hctx = NULL;

    mdlen = EVP_MD_size(digest);

    if (mdlen < 0)

        return 0;

    hctx_tpl = HMAC_CTX_new();

    if (hctx_tpl == NULL)

        return 0;

    p = out;

    tkeylen = keylen;

    if (pass == NULL) {

        pass = empty;

        passlen = 0;

    } else if (passlen == -1) {

        passlen = strlen(pass);

    }

    if (!HMAC_Init_ex(hctx_tpl, pass, passlen, digest, NULL)) {

        HMAC_CTX_free(hctx_tpl);

        return 0;

    }

    hctx = HMAC_CTX_new();

    if (hctx == NULL) {

        HMAC_CTX_free(hctx_tpl);

        return 0;

    }

    while (tkeylen) {

        if (tkeylen > mdlen)

            cplen = mdlen;

        else

            cplen = tkeylen;

        /*

         * We are unlikely to ever use more than 256 blocks (5120 bits!) but

         * just in case...

         */

        itmp[0] = (unsigned char)((i >> 24) & 0xff);

        itmp[1] = (unsigned char)((i >> 16) & 0xff);

        itmp[2] = (unsigned char)((i >> 8) & 0xff);

        itmp[3] = (unsigned char)(i & 0xff);

        if (!HMAC_CTX_copy(hctx, hctx_tpl)) {

            HMAC_CTX_free(hctx);

            HMAC_CTX_free(hctx_tpl);

            return 0;

        }

        if (!HMAC_Update(hctx, salt, saltlen)

            || !HMAC_Update(hctx, itmp, 4)

            || !HMAC_Final(hctx, digtmp, NULL)) {

            HMAC_CTX_free(hctx);

            HMAC_CTX_free(hctx_tpl);

            return 0;

        }

        memcpy(p, digtmp, cplen);

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

            if (!HMAC_CTX_copy(hctx, hctx_tpl)) {

                HMAC_CTX_free(hctx);

                HMAC_CTX_free(hctx_tpl);

                return 0;

            }

            if (!HMAC_Update(hctx, digtmp, mdlen)

                || !HMAC_Final(hctx, digtmp, NULL)) {

                HMAC_CTX_free(hctx);

                HMAC_CTX_free(hctx_tpl);

                return 0;

            }

            for (k = 0; k < cplen; k++)

                p[k] ^= digtmp[k];

        }

        tkeylen -= cplen;

        i++;

        p += cplen;

    }

    HMAC_CTX_free(hctx);

    HMAC_CTX_free(hctx_tpl);

# ifdef OPENSSL_DEBUG_PKCS5V2

    fprintf(stderr, "Password:\n");

    h__dump(pass, passlen);

    fprintf(stderr, "Salt:\n");

    h__dump(salt, saltlen);

    fprintf(stderr, "Iteration count %d\n", iter);

    fprintf(stderr, "Key:\n");

    h__dump(out, keylen);

# endif

    return 1;

}

int PKCS5_PBKDF2_HMAC_SHA1(const char *pass, int passlen,

                           const unsigned char *salt, int saltlen, int iter,

                           int keylen, unsigned char *out)

{

    return PKCS5_PBKDF2_HMAC(pass, passlen, salt, saltlen, iter, EVP_sha1(),

                             keylen, out);

}

/*

 * Now the key derivation function itself. This is a bit evil because it has

 * to check the ASN1 parameters are valid: and there are quite a few of

 * them...

 */

int PKCS5_v2_PBE_keyivgen(EVP_CIPHER_CTX *ctx, const char *pass, int passlen,

                          ASN1_TYPE *param, const EVP_CIPHER *c,

                          const EVP_MD *md, int en_de)

{

    PBE2PARAM *pbe2 = NULL;

    const EVP_CIPHER *cipher;

    EVP_PBE_KEYGEN *kdf;

    int rv = 0;

    pbe2 = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(PBE2PARAM), param);

    if (pbe2 == NULL) {

        EVPerr(EVP_F_PKCS5_V2_PBE_KEYIVGEN, EVP_R_DECODE_ERROR);

        goto err;

    }

    /* See if we recognise the key derivation function */

    if (!EVP_PBE_find(EVP_PBE_TYPE_KDF, OBJ_obj2nid(pbe2->keyfunc->algorithm),

                        NULL, NULL, &kdf)) {

        EVPerr(EVP_F_PKCS5_V2_PBE_KEYIVGEN,

               EVP_R_UNSUPPORTED_KEY_DERIVATION_FUNCTION);

        goto err;

    }

    /*

     * lets see if we recognise the encryption algorithm.

     */

    cipher = EVP_get_cipherbyobj(pbe2->encryption->algorithm);

    if (!cipher) {

        EVPerr(EVP_F_PKCS5_V2_PBE_KEYIVGEN, EVP_R_UNSUPPORTED_CIPHER);

        goto err;

    }

    /* Fixup cipher based on AlgorithmIdentifier */

    if (!EVP_CipherInit_ex(ctx, cipher, NULL, NULL, NULL, en_de))

        goto err;

    if (EVP_CIPHER_asn1_to_param(ctx, pbe2->encryption->parameter) < 0) {

        EVPerr(EVP_F_PKCS5_V2_PBE_KEYIVGEN, EVP_R_CIPHER_PARAMETER_ERROR);

        goto err;

    }

    rv = kdf(ctx, pass, passlen, pbe2->keyfunc->parameter, NULL, NULL, en_de);

 err:

    PBE2PARAM_free(pbe2);

    return rv;

}

int PKCS5_v2_PBKDF2_keyivgen(EVP_CIPHER_CTX *ctx, const char *pass,

                             int passlen, ASN1_TYPE *param,

                             const EVP_CIPHER *c, const EVP_MD *md, int en_de)

{

    unsigned char *salt, key[EVP_MAX_KEY_LENGTH];

    int saltlen, iter;

    int rv = 0;

    unsigned int keylen = 0;

    int prf_nid, hmac_md_nid;

    PBKDF2PARAM *kdf = NULL;

    const EVP_MD *prfmd;

    if (EVP_CIPHER_CTX_cipher(ctx) == NULL) {

        EVPerr(EVP_F_PKCS5_V2_PBKDF2_KEYIVGEN, EVP_R_NO_CIPHER_SET);

        goto err;

    }

    keylen = EVP_CIPHER_CTX_key_length(ctx);

    OPENSSL_assert(keylen <= sizeof(key));

    /* Decode parameter */

    kdf = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(PBKDF2PARAM), param);

    if (kdf == NULL) {

        EVPerr(EVP_F_PKCS5_V2_PBKDF2_KEYIVGEN, EVP_R_DECODE_ERROR);

        goto err;

    }

    keylen = EVP_CIPHER_CTX_key_length(ctx);

    /* Now check the parameters of the kdf */

    if (kdf->keylength && (ASN1_INTEGER_get(kdf->keylength) != (int)keylen)) {

        EVPerr(EVP_F_PKCS5_V2_PBKDF2_KEYIVGEN, EVP_R_UNSUPPORTED_KEYLENGTH);

        goto err;

    }

    if (kdf->prf)

        prf_nid = OBJ_obj2nid(kdf->prf->algorithm);

    else

        prf_nid = NID_hmacWithSHA1;

    if (!EVP_PBE_find(EVP_PBE_TYPE_PRF, prf_nid, NULL, &hmac_md_nid, 0)) {

        EVPerr(EVP_F_PKCS5_V2_PBKDF2_KEYIVGEN, EVP_R_UNSUPPORTED_PRF);

        goto err;

    }

    prfmd = EVP_get_digestbynid(hmac_md_nid);

    if (prfmd == NULL) {

        EVPerr(EVP_F_PKCS5_V2_PBKDF2_KEYIVGEN, EVP_R_UNSUPPORTED_PRF);

        goto err;

    }

    if (kdf->salt->type != V_ASN1_OCTET_STRING) {

        EVPerr(EVP_F_PKCS5_V2_PBKDF2_KEYIVGEN, EVP_R_UNSUPPORTED_SALT_TYPE);

        goto err;

    }

    /* it seems that its all OK */

    salt = kdf->salt->value.octet_string->data;

    saltlen = kdf->salt->value.octet_string->length;

    iter = ASN1_INTEGER_get(kdf->iter);

    if (!PKCS5_PBKDF2_HMAC(pass, passlen, salt, saltlen, iter, prfmd,

                           keylen, key))

        goto err;

    rv = EVP_CipherInit_ex(ctx, NULL, NULL, key, NULL, en_de);

 err:

    OPENSSL_cleanse(key, keylen);

    PBKDF2PARAM_free(kdf);

    return rv;

}

# ifdef OPENSSL_DEBUG_PKCS5V2

static void h__dump(const unsigned char *p, int len)

{

    for (; len--; p++)

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

    fprintf(stderr, "\n");

}

# endif