/* $OpenBSD: p5_pbev2.c,v 1.38 2025/05/24 02:57:14 tb Exp $ */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project 1999-2004.
 */
/* ====================================================================
 * Copyright (c) 1999 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <openssl/asn1t.h>
#include <openssl/x509.h>

#include "err_local.h"
#include "evp_local.h"
#include "x509_local.h"

/*
 * RFC 8018, sections 6.2 and 4 specify at least 64 bits for PBES2, apparently
 * FIPS will require at least 128 bits in the future, OpenSSL does that.
 */
#define PKCS5_PBE2_SALT_LEN     16

/* PKCS#5 v2.0 password based encryption structures */

static const ASN1_TEMPLATE PBE2PARAM_seq_tt[] = {
        {
                .offset = offsetof(PBE2PARAM, keyfunc),
                .field_name = "keyfunc",
                .item = &X509_ALGOR_it,
        },
        {
                .offset = offsetof(PBE2PARAM, encryption),
                .field_name = "encryption",
                .item = &X509_ALGOR_it,
        },
};

const ASN1_ITEM PBE2PARAM_it = {
        .itype = ASN1_ITYPE_SEQUENCE,
        .utype = V_ASN1_SEQUENCE,
        .templates = PBE2PARAM_seq_tt,
        .tcount = sizeof(PBE2PARAM_seq_tt) / sizeof(ASN1_TEMPLATE),
        .size = sizeof(PBE2PARAM),
        .sname = "PBE2PARAM",
};


PBE2PARAM *
d2i_PBE2PARAM(PBE2PARAM **a, const unsigned char **in, long len)
{
        return (PBE2PARAM *)ASN1_item_d2i((ASN1_VALUE **)a, in, len,
            &PBE2PARAM_it);
}

int
i2d_PBE2PARAM(PBE2PARAM *a, unsigned char **out)
{
        return ASN1_item_i2d((ASN1_VALUE *)a, out, &PBE2PARAM_it);
}

PBE2PARAM *
PBE2PARAM_new(void)
{
        return (PBE2PARAM *)ASN1_item_new(&PBE2PARAM_it);
}

void
PBE2PARAM_free(PBE2PARAM *a)
{
        ASN1_item_free((ASN1_VALUE *)a, &PBE2PARAM_it);
}

static const ASN1_TEMPLATE PBKDF2PARAM_seq_tt[] = {
        {
                .offset = offsetof(PBKDF2PARAM, salt),
                .field_name = "salt",
                .item = &ASN1_ANY_it,
        },
        {
                .offset = offsetof(PBKDF2PARAM, iter),
                .field_name = "iter",
                .item = &ASN1_INTEGER_it,
        },
        {
                .flags = ASN1_TFLG_OPTIONAL,
                .offset = offsetof(PBKDF2PARAM, keylength),
                .field_name = "keylength",
                .item = &ASN1_INTEGER_it,
        },
        {
                .flags = ASN1_TFLG_OPTIONAL,
                .offset = offsetof(PBKDF2PARAM, prf),
                .field_name = "prf",
                .item = &X509_ALGOR_it,
        },
};

const ASN1_ITEM PBKDF2PARAM_it = {
        .itype = ASN1_ITYPE_SEQUENCE,
        .utype = V_ASN1_SEQUENCE,
        .templates = PBKDF2PARAM_seq_tt,
        .tcount = sizeof(PBKDF2PARAM_seq_tt) / sizeof(ASN1_TEMPLATE),
        .size = sizeof(PBKDF2PARAM),
        .sname = "PBKDF2PARAM",
};


PBKDF2PARAM *
d2i_PBKDF2PARAM(PBKDF2PARAM **a, const unsigned char **in, long len)
{
        return (PBKDF2PARAM *)ASN1_item_d2i((ASN1_VALUE **)a, in, len,
            &PBKDF2PARAM_it);
}

int
i2d_PBKDF2PARAM(PBKDF2PARAM *a, unsigned char **out)
{
        return ASN1_item_i2d((ASN1_VALUE *)a, out, &PBKDF2PARAM_it);
}

PBKDF2PARAM *
PBKDF2PARAM_new(void)
{
        return (PBKDF2PARAM *)ASN1_item_new(&PBKDF2PARAM_it);
}

void
PBKDF2PARAM_free(PBKDF2PARAM *a)
{
        ASN1_item_free((ASN1_VALUE *)a, &PBKDF2PARAM_it);
}

/*
 * Return an algorithm identifier for a PKCS#5 v2.0 PBE algorithm:
 * yes I know this is horrible!
 */

X509_ALGOR *
PKCS5_pbe2_set(const EVP_CIPHER *cipher, int iter, unsigned char *salt,
    int saltlen)
{
        X509_ALGOR *scheme = NULL, *kalg = NULL, *ret = NULL;
        int prf_nid = NID_hmacWithSHA256;
        int alg_nid, keylen;
        EVP_CIPHER_CTX ctx;
        unsigned char iv[EVP_MAX_IV_LENGTH];
        PBE2PARAM *pbe2 = NULL;
        ASN1_OBJECT *obj;

        alg_nid = EVP_CIPHER_type(cipher);
        if (alg_nid == NID_undef) {
                ASN1error(ASN1_R_CIPHER_HAS_NO_OBJECT_IDENTIFIER);
                goto err;
        }
        obj = OBJ_nid2obj(alg_nid);

        if (!(pbe2 = PBE2PARAM_new()))
                goto merr;

        /* Setup the AlgorithmIdentifier for the encryption scheme */
        scheme = pbe2->encryption;

        scheme->algorithm = obj;
        if (!(scheme->parameter = ASN1_TYPE_new()))
                goto merr;

        /* Create random IV */
        if (EVP_CIPHER_iv_length(cipher) > 0)
                arc4random_buf(iv, EVP_CIPHER_iv_length(cipher));

        EVP_CIPHER_CTX_legacy_clear(&ctx);

        /* Dummy cipherinit to just setup the IV, and PRF */
        if (!EVP_CipherInit_ex(&ctx, cipher, NULL, NULL, iv, 0))
                goto err;
        if (EVP_CIPHER_param_to_asn1(&ctx, scheme->parameter) < 0) {
                ASN1error(ASN1_R_ERROR_SETTING_CIPHER_PARAMS);
                EVP_CIPHER_CTX_cleanup(&ctx);
                goto err;
        }
        EVP_CIPHER_CTX_cleanup(&ctx);

        /* If its RC2 then we'd better setup the key length */

        if (alg_nid == NID_rc2_cbc)
                keylen = EVP_CIPHER_key_length(cipher);
        else
                keylen = -1;

        /* Setup keyfunc */

        X509_ALGOR_free(pbe2->keyfunc);

        pbe2->keyfunc = PKCS5_pbkdf2_set(iter, salt, saltlen, prf_nid, keylen);

        if (!pbe2->keyfunc)
                goto merr;

        /* Now set up top level AlgorithmIdentifier */

        if (!(ret = X509_ALGOR_new()))
                goto merr;
        if (!(ret->parameter = ASN1_TYPE_new()))
                goto merr;

        ret->algorithm = OBJ_nid2obj(NID_pbes2);

        /* Encode PBE2PARAM into parameter */

        if (!ASN1_item_pack(pbe2, &PBE2PARAM_it,
                &ret->parameter->value.sequence)) goto merr;
        ret->parameter->type = V_ASN1_SEQUENCE;

        PBE2PARAM_free(pbe2);
        pbe2 = NULL;

        return ret;

 merr:
        ASN1error(ERR_R_MALLOC_FAILURE);

 err:
        PBE2PARAM_free(pbe2);
        /* Note 'scheme' is freed as part of pbe2 */
        X509_ALGOR_free(kalg);
        X509_ALGOR_free(ret);

        return NULL;
}

X509_ALGOR *
PKCS5_pbkdf2_set(int iter, unsigned char *salt, int saltlen, int prf_nid,
    int keylen)
{
        X509_ALGOR *keyfunc = NULL;
        PBKDF2PARAM *kdf = NULL;
        ASN1_OCTET_STRING *osalt = NULL;

        if (!(kdf = PBKDF2PARAM_new()))
                goto merr;
        if (!(osalt = ASN1_OCTET_STRING_new()))
                goto merr;

        kdf->salt->value.octet_string = osalt;
        kdf->salt->type = V_ASN1_OCTET_STRING;

        if (!saltlen)
                saltlen = PKCS5_PBE2_SALT_LEN;
        if (!(osalt->data = malloc (saltlen)))
                goto merr;

        osalt->length = saltlen;

        if (salt)
                memcpy (osalt->data, salt, saltlen);
        else
                arc4random_buf(osalt->data, saltlen);

        if (iter <= 0)
                iter = PKCS5_DEFAULT_ITER;

        if (!ASN1_INTEGER_set(kdf->iter, iter))
                goto merr;

        /* If have a key len set it up */

        if (keylen > 0) {
                if (!(kdf->keylength = ASN1_INTEGER_new()))
                        goto merr;
                if (!ASN1_INTEGER_set(kdf->keylength, keylen))
                        goto merr;
        }

        /* prf can stay NULL if we are using hmacWithSHA1 */
        if (prf_nid > 0 && prf_nid != NID_hmacWithSHA1) {
                kdf->prf = X509_ALGOR_new();
                if (!kdf->prf)
                        goto merr;
                X509_ALGOR_set0(kdf->prf, OBJ_nid2obj(prf_nid),
                V_ASN1_NULL, NULL);
        }

        /* Finally setup the keyfunc structure */

        keyfunc = X509_ALGOR_new();
        if (!keyfunc)
                goto merr;

        keyfunc->algorithm = OBJ_nid2obj(NID_id_pbkdf2);

        /* Encode PBKDF2PARAM into parameter of pbe2 */

        if (!(keyfunc->parameter = ASN1_TYPE_new()))
                goto merr;

        if (!ASN1_item_pack(kdf, &PBKDF2PARAM_it,
                &keyfunc->parameter->value.sequence))
                goto merr;
        keyfunc->parameter->type = V_ASN1_SEQUENCE;

        PBKDF2PARAM_free(kdf);
        return keyfunc;

 merr:
        ASN1error(ERR_R_MALLOC_FAILURE);
        PBKDF2PARAM_free(kdf);
        X509_ALGOR_free(keyfunc);
        return NULL;
}