/* $OpenBSD: cms_enc.c,v 1.25 2024/11/01 18:34:06 tb Exp $ */

/*

 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL

 * project.

 */

/* ====================================================================

 * Copyright (c) 2008 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.

 * ====================================================================

 */

#include <stdlib.h>

#include <string.h>

#include <openssl/asn1.h>

#include <openssl/bio.h>

#include <openssl/cms.h>

#include <openssl/err.h>

#include <openssl/evp.h>

#include <openssl/objects.h>

#include <openssl/x509.h>

#include "cms_local.h"

#include "evp_local.h"

/* CMS EncryptedData Utilities */

/* Return BIO based on EncryptedContentInfo and key */

BIO *

cms_EncryptedContent_init_bio(CMS_EncryptedContentInfo *ec)

{

  BIO *b;

  EVP_CIPHER_CTX *ctx;

  const EVP_CIPHER *ciph;

  X509_ALGOR *calg = ec->contentEncryptionAlgorithm;

  unsigned char iv[EVP_MAX_IV_LENGTH], *piv = NULL;

  unsigned char *tkey = NULL;

  size_t tkeylen = 0;

  int ok = 0;

  int enc, keep_key = 0;

  enc = ec->cipher ? 1 : 0;

  b = BIO_new(BIO_f_cipher());

  if (b == NULL) {

    CMSerror(ERR_R_MALLOC_FAILURE);

    return NULL;

  }

  BIO_get_cipher_ctx(b, &ctx);

  if (enc) {

    ciph = ec->cipher;

    /*

     * If not keeping key set cipher to NULL so subsequent calls decrypt.

     */

    if (ec->key)

      ec->cipher = NULL;

  } else {

    ciph = EVP_get_cipherbyobj(calg->algorithm);

    if (!ciph) {

      CMSerror(CMS_R_UNKNOWN_CIPHER);

      goto err;

    }

  }

  if (EVP_CipherInit_ex(ctx, ciph, NULL, NULL, NULL, enc) <= 0) {

    CMSerror(CMS_R_CIPHER_INITIALISATION_ERROR);

    goto err;

  }

  if (enc) {

    int ivlen;

    calg->algorithm = OBJ_nid2obj(EVP_CIPHER_CTX_type(ctx));

    /* Generate a random IV if we need one */

    ivlen = EVP_CIPHER_CTX_iv_length(ctx);

    if (ivlen > 0) {

      arc4random_buf(iv, ivlen);

      piv = iv;

    }

  } else if (EVP_CIPHER_asn1_to_param(ctx, calg->parameter) <= 0) {

    CMSerror(CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);

    goto err;

  }

  tkeylen = EVP_CIPHER_CTX_key_length(ctx);

  /* Generate random session key */

  if (!enc || !ec->key) {

    tkey = malloc(tkeylen);

    if (tkey == NULL) {

      CMSerror(ERR_R_MALLOC_FAILURE);

      goto err;

    }

    if (EVP_CIPHER_CTX_rand_key(ctx, tkey) <= 0)

      goto err;

  }

  if (!ec->key) {

    ec->key = tkey;

    ec->keylen = tkeylen;

    tkey = NULL;

    if (enc)

      keep_key = 1;

    else

      ERR_clear_error();

  }

  if (ec->keylen != tkeylen) {

    /* If necessary set key length */

    if (!EVP_CIPHER_CTX_set_key_length(ctx, ec->keylen)) {

      /*

       * Only reveal failure if debugging so we don't leak information

       * which may be useful in MMA.

       */

      if (enc || ec->debug) {

          CMSerror(CMS_R_INVALID_KEY_LENGTH);

          goto err;

      } else {

          /* Use random key */

          freezero(ec->key, ec->keylen);

          ec->key = tkey;

          ec->keylen = tkeylen;

          tkey = NULL;

          ERR_clear_error();

      }

    }

  }

  if (EVP_CipherInit_ex(ctx, NULL, NULL, ec->key, piv, enc) <= 0) {

    CMSerror(CMS_R_CIPHER_INITIALISATION_ERROR);

    goto err;

  }

  if (enc) {

    calg->parameter = ASN1_TYPE_new();

    if (calg->parameter == NULL) {

      CMSerror(ERR_R_MALLOC_FAILURE);

      goto err;

    }

    if (EVP_CIPHER_param_to_asn1(ctx, calg->parameter) <= 0) {

      CMSerror(CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);

      goto err;

    }

    /* If parameter type not set omit parameter */

    if (calg->parameter->type == V_ASN1_UNDEF) {

      ASN1_TYPE_free(calg->parameter);

      calg->parameter = NULL;

    }

  }

  ok = 1;

 err:

  if (!keep_key || !ok) {

    freezero(ec->key, ec->keylen);

    ec->key = NULL;

  }

  freezero(tkey, tkeylen);

  if (ok)

    return b;

  BIO_free(b);

  return NULL;

}

int

cms_EncryptedContent_init(CMS_EncryptedContentInfo *ec,

    const EVP_CIPHER *cipher, const unsigned char *key, size_t keylen)

{

  ec->cipher = cipher;

  if (key) {

    if ((ec->key = malloc(keylen)) == NULL) {

      CMSerror(ERR_R_MALLOC_FAILURE);

      return 0;

    }

    memcpy(ec->key, key, keylen);

  }

  ec->keylen = keylen;

  if (cipher)

    ec->contentType = OBJ_nid2obj(NID_pkcs7_data);

  return 1;

}

int

CMS_EncryptedData_set1_key(CMS_ContentInfo *cms, const EVP_CIPHER *ciph,

    const unsigned char *key, size_t keylen)

{

  CMS_EncryptedContentInfo *ec;

  if (!key || !keylen) {

    CMSerror(CMS_R_NO_KEY);

    return 0;

  }

  if (ciph) {

    cms->d.encryptedData = (CMS_EncryptedData *)ASN1_item_new(&CMS_EncryptedData_it);

    if (!cms->d.encryptedData) {

      CMSerror(ERR_R_MALLOC_FAILURE);

      return 0;

    }

    cms->contentType = OBJ_nid2obj(NID_pkcs7_encrypted);

    cms->d.encryptedData->version = 0;

  } else if (OBJ_obj2nid(cms->contentType) != NID_pkcs7_encrypted) {

    CMSerror(CMS_R_NOT_ENCRYPTED_DATA);

    return 0;

  }

  ec = cms->d.encryptedData->encryptedContentInfo;

  return cms_EncryptedContent_init(ec, ciph, key, keylen);

}

LCRYPTO_ALIAS(CMS_EncryptedData_set1_key);

BIO *

cms_EncryptedData_init_bio(CMS_ContentInfo *cms)

{

  CMS_EncryptedData *enc = cms->d.encryptedData;

  if (enc->encryptedContentInfo->cipher && enc->unprotectedAttrs)

    enc->version = 2;

  return cms_EncryptedContent_init_bio(enc->encryptedContentInfo);

}