cms_enc.c

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/* crypto/cms/cms_enc.c */
/* Written by Dr Stephen N Henson ([email protected]) 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
 *    [email protected].
 *
 * 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;

    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);
    }