/* 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)

        return NULL;

    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();

    if (encalg == NULL) {

        goto merr;

    }

    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_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);

    if (!tmp)

        return 0;

    /* 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_bytes(out + 4 + inlen, olen - 4 - inlen) <= 0)

            return 0;

        /* 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;

}