/* $OpenBSD: cms_enc.c,v 1.26 2025/05/10 05:54:38 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/evp.h>
#include <openssl/objects.h>
#include <openssl/x509.h>

#include "cms_local.h"
#include "err_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);
}