text: /* crypto/cms/cms_enc.c */
  /* 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 "cryptlib.h"
  #include <openssl/asn1t.h>
  #include <openssl/pem.h>
  #include <openssl/x509v3.h>
  #include <openssl/err.h>
  #include <openssl/cms.h>
  #include <openssl/rand.h>
  #include "cms_lcl.h"
  
  /* CMS EncryptedData Utilities */
  
  DECLARE_ASN1_ITEM(CMS_EncryptedData)
  
  /* 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)
  		{
  		CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
  							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)
  			{
  			CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
  							CMS_R_UNKNOWN_CIPHER);
  			goto err;
  			}
  		}
  
  	if (EVP_CipherInit_ex(ctx, ciph, NULL, NULL, NULL, enc) <= 0)
  		{
  		CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
  				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)
  			{
  			if (RAND_pseudo_bytes(iv, ivlen) <= 0)
  				goto err;
  			piv = iv;
  			}
  		}
  	else if (EVP_CIPHER_asn1_to_param(ctx, calg->parameter) <= 0)
  		{
  		CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
  				CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
  		goto err;
  		}
  	tkeylen = EVP_CIPHER_CTX_key_length(ctx);
  	/* Generate random session key */
  	if (!enc || !ec->key)
  		{
  		tkey = OPENSSL_malloc(tkeylen);
  		if (!tkey)
  			{
  			CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
  							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) <= 0)
  			{
  			/* Only reveal failure if debugging so we don't
  			 * leak information which may be useful in MMA.
  			 */
  			if (enc || ec->debug)
  				{
  				CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
  						CMS_R_INVALID_KEY_LENGTH);
  				goto err;
  				}
  			else
  				{
  				/* Use random key */
  				OPENSSL_cleanse(ec->key, ec->keylen);
  				OPENSSL_free(ec->key);
  				ec->key = tkey;
  				ec->keylen = tkeylen;
  				tkey = NULL;
  				ERR_clear_error();
  				}
  			}
  		}
  
  	if (EVP_CipherInit_ex(ctx, NULL, NULL, ec->key, piv, enc) <= 0)
  		{
  		CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
  				CMS_R_CIPHER_INITIALISATION_ERROR);
  		goto err;
  		}
  
  	if (piv)
  		{
  		calg->parameter = ASN1_TYPE_new();
  		if (!calg->parameter)
  			{
  			CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
  							ERR_R_MALLOC_FAILURE);
  			goto err;
  			}
  		if (EVP_CIPHER_param_to_asn1(ctx, calg->parameter) <= 0)
  			{
  			CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
  				CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
  			goto err;
  			}
  		}
  	ok = 1;
  
  	err:
  	if (ec->key && !keep_key)
  		{
  		OPENSSL_cleanse(ec->key, ec->keylen);
  		OPENSSL_free(ec->key);
  		ec->key = NULL;
  		}
  	if (tkey)
  		{
  		OPENSSL_cleanse(tkey, tkeylen);
  		OPENSSL_free(tkey);
  		}
  	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)
  		{
  		ec->key = OPENSSL_malloc(keylen);
  		if (!ec->key)
  			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)
  		{
  		CMSerr(CMS_F_CMS_ENCRYPTEDDATA_SET1_KEY, CMS_R_NO_KEY);
  		return 0;
  		}
  	if (ciph)
  		{
  		cms->d.encryptedData = M_ASN1_new_of(CMS_EncryptedData);
  		if (!cms->d.encryptedData)
  			{
  			CMSerr(CMS_F_CMS_ENCRYPTEDDATA_SET1_KEY,
  				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)
  		{
  		CMSerr(CMS_F_CMS_ENCRYPTEDDATA_SET1_KEY,
  						CMS_R_NOT_ENCRYPTED_DATA);
  		return 0;
  		}
  	ec = cms->d.encryptedData->encryptedContentInfo;
  	return cms_EncryptedContent_init(ec, ciph, key, keylen);
  	}
  
  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);
  	}
  