text: /* crypto/cms/cms_pwri.c */
  /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   * project.
   */
  /* ====================================================================
   * Copyright (c) 2009 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 <openssl/aes.h>
  #include "cms_lcl.h"
  #include "asn1_locl.h"
  
  int CMS_RecipientInfo_set0_password(CMS_RecipientInfo *ri, 
  				unsigned char *pass, ossl_ssize_t passlen)
  	{
  	CMS_PasswordRecipientInfo *pwri;
  	if (ri->type != CMS_RECIPINFO_PASS)
  		{
  		CMSerr(CMS_F_CMS_RECIPIENTINFO_SET0_PASSWORD, CMS_R_NOT_PWRI);
  		return 0;
  		}
  
  	pwri = ri->d.pwri;
  	pwri->pass = pass;
  	if (pass && passlen < 0)
  		passlen = strlen((char *)pass);
  	pwri->passlen = passlen;
  	return 1;
  	}
  
  CMS_RecipientInfo *CMS_add0_recipient_password(CMS_ContentInfo *cms,
  					int iter, int wrap_nid, int pbe_nid,
  					unsigned char *pass,
  					ossl_ssize_t passlen,
  					const EVP_CIPHER *kekciph)
  	{
  	CMS_RecipientInfo *ri = NULL;
  	CMS_EnvelopedData *env;
  	CMS_PasswordRecipientInfo *pwri;
  	EVP_CIPHER_CTX ctx;
  	X509_ALGOR *encalg = NULL;
  	unsigned char iv[EVP_MAX_IV_LENGTH];
  	int ivlen;
  	env = cms_get0_enveloped(cms);
  	if (!env)
  		goto err;
  
  	if (wrap_nid <= 0)
  		wrap_nid = NID_id_alg_PWRI_KEK;
  
  	if (pbe_nid <= 0)
  		pbe_nid = NID_id_pbkdf2;
  
  	/* Get from enveloped data */
  	if (kekciph == NULL)
  		kekciph = env->encryptedContentInfo->cipher;
  
  	if (kekciph == NULL)
  		{
  		CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, CMS_R_NO_CIPHER);
  		return NULL;
  		}
  	if (wrap_nid != NID_id_alg_PWRI_KEK)
  		{
  		CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD,
  				CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);
  		return NULL;
  		}
  
  	/* Setup algorithm identifier for cipher */
  	encalg = X509_ALGOR_new();
  	EVP_CIPHER_CTX_init(&ctx);
  
  	if (EVP_EncryptInit_ex(&ctx, kekciph, NULL, NULL, NULL) <= 0)
  		{
  		CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, ERR_R_EVP_LIB);
  		goto err;
  		}
  
  	ivlen = EVP_CIPHER_CTX_iv_length(&ctx);
  
  	if (ivlen > 0)
  		{
  		if (RAND_pseudo_bytes(iv, ivlen) <= 0)
  			goto err;
  		if (EVP_EncryptInit_ex(&ctx, NULL, NULL, NULL, iv) <= 0)
  			{
  			CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD,
  							ERR_R_EVP_LIB);
  			goto err;
  			}
  		encalg->parameter = ASN1_TYPE_new();
  		if (!encalg->parameter)
  			{
  			CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD,
  							ERR_R_MALLOC_FAILURE);
  			goto err;
  			}
  		if (EVP_CIPHER_param_to_asn1(&ctx, encalg->parameter) <= 0)
  			{
  			CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD,
  				CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
  			goto err;
  			}
  		}
  
  
  	encalg->algorithm = OBJ_nid2obj(EVP_CIPHER_CTX_type(&ctx));
  
  	EVP_CIPHER_CTX_cleanup(&ctx);
  
  	/* Initialize recipient info */
  	ri = M_ASN1_new_of(CMS_RecipientInfo);
  	if (!ri)
  		goto merr;
  
  	ri->d.pwri = M_ASN1_new_of(CMS_PasswordRecipientInfo);
  	if (!ri->d.pwri)
  		goto merr;
  	ri->type = CMS_RECIPINFO_PASS;
  
  	pwri = ri->d.pwri;
  	/* Since this is overwritten, free up empty structure already there */
  	X509_ALGOR_free(pwri->keyEncryptionAlgorithm);
  	pwri->keyEncryptionAlgorithm = X509_ALGOR_new();
  	if (!pwri->keyEncryptionAlgorithm)
  		goto merr;
  	pwri->keyEncryptionAlgorithm->algorithm = OBJ_nid2obj(wrap_nid);
  	pwri->keyEncryptionAlgorithm->parameter = ASN1_TYPE_new();
  	if (!pwri->keyEncryptionAlgorithm->parameter)
  		goto merr;
  
          if(!ASN1_item_pack(encalg, ASN1_ITEM_rptr(X509_ALGOR),
  	    &pwri->keyEncryptionAlgorithm->parameter->value.sequence))
  		goto merr;
          pwri->keyEncryptionAlgorithm->parameter->type = V_ASN1_SEQUENCE;
  
  	X509_ALGOR_free(encalg);
  	encalg = NULL;
  
  	/* Setup PBE algorithm */
  
  	pwri->keyDerivationAlgorithm = PKCS5_pbkdf2_set(iter, NULL, 0, -1, -1);
  
  	if (!pwri->keyDerivationAlgorithm)
  		goto err;
  
  	CMS_RecipientInfo_set0_password(ri, pass, passlen);
  	pwri->version = 0;
  
  	if (!sk_CMS_RecipientInfo_push(env->recipientInfos, ri))
  		goto merr;
  
  	return ri;
  
  	merr:
  	CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, ERR_R_MALLOC_FAILURE);
  	err:
  	EVP_CIPHER_CTX_cleanup(&ctx);
  	if (ri)
  		M_ASN1_free_of(ri, CMS_RecipientInfo);
  	if (encalg)
  		X509_ALGOR_free(encalg);
  	return NULL;
  
  	}
  
  /* This is an implementation of the key wrapping mechanism in RFC3211,
   * at some point this should go into EVP.
   */
  
  static int kek_unwrap_key(unsigned char *out, size_t *outlen,
  		const unsigned char *in, size_t inlen, EVP_CIPHER_CTX *ctx)
  	{
  	size_t blocklen = EVP_CIPHER_CTX_block_size(ctx);
  	unsigned char *tmp;
  	int outl, rv = 0;
  	if (inlen < 2 * blocklen)
  		{
  		/* too small */
  		return 0;
  		}
  	if (inlen % blocklen)
  		{
  		/* Invalid size */
  		return 0;
  		}
  	tmp = OPENSSL_malloc(inlen);
  	/* setup IV by decrypting last two blocks */
  	EVP_DecryptUpdate(ctx, tmp + inlen - 2 * blocklen, &outl,
  				in  + inlen - 2 * blocklen, blocklen * 2);
  	/* Do a decrypt of last decrypted block to set IV to correct value
  	 * output it to start of buffer so we don't corrupt decrypted block
  	 * this works because buffer is at least two block lengths long.
  	 */
  	EVP_DecryptUpdate(ctx, tmp, &outl,
  				tmp  + inlen - blocklen, blocklen);
  	/* Can now decrypt first n - 1 blocks */
  	EVP_DecryptUpdate(ctx, tmp, &outl, in, inlen - blocklen);
  
  	/* Reset IV to original value */
  	EVP_DecryptInit_ex(ctx, NULL, NULL, NULL, NULL);
  	/* Decrypt again */
  	EVP_DecryptUpdate(ctx, tmp, &outl, tmp, inlen);
  	/* Check check bytes */
  	if (((tmp[1] ^ tmp[4]) & (tmp[2] ^ tmp[5]) & (tmp[3] ^ tmp[6])) != 0xff)
  		{
  		/* Check byte failure */
  		goto err;
  		}
  	if (inlen < (size_t)(tmp[0] - 4 ))
  		{
  		/* Invalid length value */
  		goto err;
  		}
  	*outlen = (size_t)tmp[0];
  	memcpy(out, tmp + 4, *outlen);
  	rv = 1;
  	err:
  	OPENSSL_cleanse(tmp, inlen);
  	OPENSSL_free(tmp);
  	return rv;
  
  	}
  
  static int kek_wrap_key(unsigned char *out, size_t *outlen,
  		const unsigned char *in, size_t inlen, EVP_CIPHER_CTX *ctx)
  	{
  	size_t blocklen = EVP_CIPHER_CTX_block_size(ctx);
  	size_t olen;
  	int dummy;
  	/* First decide length of output buffer: need header and round up to
  	 * multiple of block length.
  	 */
  	olen = (inlen + 4 + blocklen - 1)/blocklen;
  	olen *= blocklen;
  	if (olen < 2 * blocklen)
  		{
  		/* Key too small */
  		return 0;
  		}
  	if (inlen > 0xFF)
  		{
  		/* Key too large */
  		return 0;
  		}
  	if (out)
  		{
  		/* Set header */
  		out[0] = (unsigned char)inlen;
  		out[1] = in[0] ^ 0xFF;
  		out[2] = in[1] ^ 0xFF;
  		out[3] = in[2] ^ 0xFF;
  		memcpy(out + 4, in, inlen);
  		/* Add random padding to end */
  		if (olen > inlen + 4)
  			RAND_pseudo_bytes(out + 4 + inlen, olen - 4 - inlen);
  		/* Encrypt twice */
  		EVP_EncryptUpdate(ctx, out, &dummy, out, olen);
  		EVP_EncryptUpdate(ctx, out, &dummy, out, olen);
  		}
  
  	*outlen = olen;
  
  	return 1;
  	}
  
  /* Encrypt/Decrypt content key in PWRI recipient info */
  
  int cms_RecipientInfo_pwri_crypt(CMS_ContentInfo *cms, CMS_RecipientInfo *ri,
  							int en_de)
  	{
  	CMS_EncryptedContentInfo *ec;
  	CMS_PasswordRecipientInfo *pwri;
  	const unsigned char *p = NULL;
  	int plen;
  	int r = 0;
  	X509_ALGOR *algtmp, *kekalg = NULL;
  	EVP_CIPHER_CTX kekctx;
  	const EVP_CIPHER *kekcipher;
  	unsigned char *key = NULL;
  	size_t keylen;
  
  	ec = cms->d.envelopedData->encryptedContentInfo;
  
  	pwri = ri->d.pwri;
  	EVP_CIPHER_CTX_init(&kekctx);
  
  	if (!pwri->pass)
  		{
  		CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, CMS_R_NO_PASSWORD);
  		return 0;
  		}
  	algtmp = pwri->keyEncryptionAlgorithm;
  
  	if (!algtmp || OBJ_obj2nid(algtmp->algorithm) != NID_id_alg_PWRI_KEK)
  		{
  		CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT,
  				CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);
  		return 0;
  		}
  
  	if (algtmp->parameter->type == V_ASN1_SEQUENCE)
  		{
  		p = algtmp->parameter->value.sequence->data;
  		plen = algtmp->parameter->value.sequence->length;
  		kekalg = d2i_X509_ALGOR(NULL, &p, plen);
  		}
  	if (kekalg == NULL)
  		{
  		CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT,
  				CMS_R_INVALID_KEY_ENCRYPTION_PARAMETER);
  		return 0;
  		}
  
  	kekcipher = EVP_get_cipherbyobj(kekalg->algorithm);
  		
  	if(!kekcipher)
  		{
  		CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT,
  				CMS_R_UNKNOWN_CIPHER);
  		goto err;
  		}
  
  	/* Fixup cipher based on AlgorithmIdentifier to set IV etc */
  	if (!EVP_CipherInit_ex(&kekctx, kekcipher, NULL, NULL, NULL, en_de))
  		goto err;
  	EVP_CIPHER_CTX_set_padding(&kekctx, 0);
  	if(EVP_CIPHER_asn1_to_param(&kekctx, kekalg->parameter) < 0)
  		{
  		CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT,
  				CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
  		goto err;
  		}
  
  	algtmp = pwri->keyDerivationAlgorithm;
  
  	/* Finish password based key derivation to setup key in "ctx" */
  
  	if (EVP_PBE_CipherInit(algtmp->algorithm,
  				(char *)pwri->pass, pwri->passlen,
  				algtmp->parameter, &kekctx, en_de) < 0)
  		{
  		CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, ERR_R_EVP_LIB);
  		goto err;
  		}
  
  	/* Finally wrap/unwrap the key */
  
  	if (en_de)
  		{
  
  		if (!kek_wrap_key(NULL, &keylen, ec->key, ec->keylen, &kekctx))
  			goto err;
  
  		key = OPENSSL_malloc(keylen);
  
  		if (!key)
  			goto err;
  
  		if (!kek_wrap_key(key, &keylen, ec->key, ec->keylen, &kekctx))
  			goto err;
  		pwri->encryptedKey->data = key;
  		pwri->encryptedKey->length = keylen;
  		}
  	else
  		{
  		key = OPENSSL_malloc(pwri->encryptedKey->length);
  
  		if (!key)
  			{
  			CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT,
  							ERR_R_MALLOC_FAILURE);
  			goto err;
  			}
  		if (!kek_unwrap_key(key, &keylen,
  					pwri->encryptedKey->data,
  					pwri->encryptedKey->length, &kekctx))
  			{
  			CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT,
  							CMS_R_UNWRAP_FAILURE);
  			goto err;
  			}
  
  		ec->key = key;
  		ec->keylen = keylen;
  
  		}
  
  	r = 1;
  
  	err:
  
  	EVP_CIPHER_CTX_cleanup(&kekctx);
  
  	if (!r && key)
  		OPENSSL_free(key);
  	X509_ALGOR_free(kekalg);
  
  	return r;
  
  	}
  