/* crypto/cms/cms_kari.c */

/*

 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL

 * project.

 */

/* ====================================================================

 * Copyright (c) 2013 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"

DECLARE_ASN1_ITEM(CMS_KeyAgreeRecipientInfo)

DECLARE_ASN1_ITEM(CMS_RecipientEncryptedKey)

DECLARE_ASN1_ITEM(CMS_OriginatorPublicKey)

DECLARE_ASN1_ITEM(CMS_RecipientKeyIdentifier)

/* Key Agreement Recipient Info (KARI) routines */

int CMS_RecipientInfo_kari_get0_alg(CMS_RecipientInfo *ri,

                                    X509_ALGOR **palg,

                                    ASN1_OCTET_STRING **pukm)

{

    if (ri->type != CMS_RECIPINFO_AGREE) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_GET0_ALG,

               CMS_R_NOT_KEY_AGREEMENT);

        return 0;

    }

    if (palg)

        *palg = ri->d.kari->keyEncryptionAlgorithm;

    if (pukm)

        *pukm = ri->d.kari->ukm;

    return 1;

}

/* Retrieve recipient encrypted keys from a kari */

STACK_OF(CMS_RecipientEncryptedKey)

*CMS_RecipientInfo_kari_get0_reks(CMS_RecipientInfo *ri)

{

    if (ri->type != CMS_RECIPINFO_AGREE) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_GET0_REKS,

               CMS_R_NOT_KEY_AGREEMENT);

        return NULL;

    }

    return ri->d.kari->recipientEncryptedKeys;

}

int CMS_RecipientInfo_kari_get0_orig_id(CMS_RecipientInfo *ri,

                                        X509_ALGOR **pubalg,

                                        ASN1_BIT_STRING **pubkey,

                                        ASN1_OCTET_STRING **keyid,

                                        X509_NAME **issuer,

                                        ASN1_INTEGER **sno)

{

    CMS_OriginatorIdentifierOrKey *oik;

    if (ri->type != CMS_RECIPINFO_AGREE) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_GET0_ORIG_ID,

               CMS_R_NOT_KEY_AGREEMENT);

        return 0;

    }

    oik = ri->d.kari->originator;

    if (issuer)

        *issuer = NULL;

    if (sno)

        *sno = NULL;

    if (keyid)

        *keyid = NULL;

    if (pubalg)

        *pubalg = NULL;

    if (pubkey)

        *pubkey = NULL;

    if (oik->type == CMS_OIK_ISSUER_SERIAL) {

        if (issuer)

            *issuer = oik->d.issuerAndSerialNumber->issuer;

        if (sno)

            *sno = oik->d.issuerAndSerialNumber->serialNumber;

    } else if (oik->type == CMS_OIK_KEYIDENTIFIER) {

        if (keyid)

            *keyid = oik->d.subjectKeyIdentifier;

    } else if (oik->type == CMS_OIK_PUBKEY) {

        if (pubalg)

            *pubalg = oik->d.originatorKey->algorithm;

        if (pubkey)

            *pubkey = oik->d.originatorKey->publicKey;

    } else

        return 0;

    return 1;

}

int CMS_RecipientInfo_kari_orig_id_cmp(CMS_RecipientInfo *ri, X509 *cert)

{

    CMS_OriginatorIdentifierOrKey *oik;

    if (ri->type != CMS_RECIPINFO_AGREE) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_ORIG_ID_CMP,

               CMS_R_NOT_KEY_AGREEMENT);

        return -2;

    }

    oik = ri->d.kari->originator;

    if (oik->type == CMS_OIK_ISSUER_SERIAL)

        return cms_ias_cert_cmp(oik->d.issuerAndSerialNumber, cert);

    else if (oik->type == CMS_OIK_KEYIDENTIFIER)

        return cms_keyid_cert_cmp(oik->d.subjectKeyIdentifier, cert);

    return -1;

}

int CMS_RecipientEncryptedKey_get0_id(CMS_RecipientEncryptedKey *rek,

                                      ASN1_OCTET_STRING **keyid,

                                      ASN1_GENERALIZEDTIME **tm,

                                      CMS_OtherKeyAttribute **other,

                                      X509_NAME **issuer, ASN1_INTEGER **sno)

{

    CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;

    if (rid->type == CMS_REK_ISSUER_SERIAL) {

        if (issuer)

            *issuer = rid->d.issuerAndSerialNumber->issuer;

        if (sno)

            *sno = rid->d.issuerAndSerialNumber->serialNumber;

        if (keyid)

            *keyid = NULL;

        if (tm)

            *tm = NULL;

        if (other)

            *other = NULL;

    } else if (rid->type == CMS_REK_KEYIDENTIFIER) {

        if (keyid)

            *keyid = rid->d.rKeyId->subjectKeyIdentifier;

        if (tm)

            *tm = rid->d.rKeyId->date;

        if (other)

            *other = rid->d.rKeyId->other;

        if (issuer)

            *issuer = NULL;

        if (sno)

            *sno = NULL;

    } else

        return 0;

    return 1;

}

int CMS_RecipientEncryptedKey_cert_cmp(CMS_RecipientEncryptedKey *rek,

                                       X509 *cert)

{

    CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;

    if (rid->type == CMS_REK_ISSUER_SERIAL)

        return cms_ias_cert_cmp(rid->d.issuerAndSerialNumber, cert);

    else if (rid->type == CMS_REK_KEYIDENTIFIER)

        return cms_keyid_cert_cmp(rid->d.rKeyId->subjectKeyIdentifier, cert);

    else

        return -1;

}

int CMS_RecipientInfo_kari_set0_pkey(CMS_RecipientInfo *ri, EVP_PKEY *pk)

{

    EVP_PKEY_CTX *pctx;

    CMS_KeyAgreeRecipientInfo *kari = ri->d.kari;

    if (kari->pctx) {

        EVP_PKEY_CTX_free(kari->pctx);

        kari->pctx = NULL;

    }

    if (!pk)

        return 1;

    pctx = EVP_PKEY_CTX_new(pk, NULL);

    if (!pctx || !EVP_PKEY_derive_init(pctx))

        goto err;

    kari->pctx = pctx;

    return 1;

 err:

    if (pctx)

        EVP_PKEY_CTX_free(pctx);

    return 0;

}

EVP_CIPHER_CTX *CMS_RecipientInfo_kari_get0_ctx(CMS_RecipientInfo *ri)

{

    if (ri->type == CMS_RECIPINFO_AGREE)

        return &ri->d.kari->ctx;

    return NULL;

}

/*

 * Derive KEK and decrypt/encrypt with it to produce either the original CEK

 * or the encrypted CEK.

 */

static int cms_kek_cipher(unsigned char **pout, size_t *poutlen,

                          const unsigned char *in, size_t inlen,

                          CMS_KeyAgreeRecipientInfo *kari, int enc)

{

    /* Key encryption key */

    unsigned char kek[EVP_MAX_KEY_LENGTH];

    size_t keklen;

    int rv = 0;

    unsigned char *out = NULL;

    int outlen;

    keklen = EVP_CIPHER_CTX_key_length(&kari->ctx);

    if (keklen > EVP_MAX_KEY_LENGTH)

        return 0;

    /* Derive KEK */

    if (EVP_PKEY_derive(kari->pctx, kek, &keklen) <= 0)

        goto err;

    /* Set KEK in context */

    if (!EVP_CipherInit_ex(&kari->ctx, NULL, NULL, kek, NULL, enc))

        goto err;

    /* obtain output length of ciphered key */

    if (!EVP_CipherUpdate(&kari->ctx, NULL, &outlen, in, inlen))

        goto err;

    out = OPENSSL_malloc(outlen);

    if (!out)

        goto err;

    if (!EVP_CipherUpdate(&kari->ctx, out, &outlen, in, inlen))

        goto err;

    *pout = out;

    *poutlen = (size_t)outlen;

    rv = 1;

 err:

    OPENSSL_cleanse(kek, keklen);

    if (!rv && out)

        OPENSSL_free(out);

    EVP_CIPHER_CTX_cleanup(&kari->ctx);

    EVP_PKEY_CTX_free(kari->pctx);

    kari->pctx = NULL;

    return rv;

}

int CMS_RecipientInfo_kari_decrypt(CMS_ContentInfo *cms,

                                   CMS_RecipientInfo *ri,

                                   CMS_RecipientEncryptedKey *rek)

{

    int rv = 0;

    unsigned char *enckey = NULL, *cek = NULL;

    size_t enckeylen;

    size_t ceklen;

    CMS_EncryptedContentInfo *ec;

    enckeylen = rek->encryptedKey->length;

    enckey = rek->encryptedKey->data;

    /* Setup all parameters to derive KEK */

    if (!cms_env_asn1_ctrl(ri, 1))

        goto err;

    /* Attempt to decrypt CEK */

    if (!cms_kek_cipher(&cek, &ceklen, enckey, enckeylen, ri->d.kari, 0))

        goto err;

    ec = cms->d.envelopedData->encryptedContentInfo;

    if (ec->key) {

        OPENSSL_cleanse(ec->key, ec->keylen);

        OPENSSL_free(ec->key);

    }

    ec->key = cek;

    ec->keylen = ceklen;

    cek = NULL;

    rv = 1;

 err:

    if (cek)

        OPENSSL_free(cek);

    return rv;

}

/* Create ephemeral key and initialise context based on it */

static int cms_kari_create_ephemeral_key(CMS_KeyAgreeRecipientInfo *kari,

                                         EVP_PKEY *pk)

{

    EVP_PKEY_CTX *pctx = NULL;

    EVP_PKEY *ekey = NULL;

    int rv = 0;

    pctx = EVP_PKEY_CTX_new(pk, NULL);

    if (!pctx)

        goto err;

    if (EVP_PKEY_keygen_init(pctx) <= 0)

        goto err;

    if (EVP_PKEY_keygen(pctx, &ekey) <= 0)

        goto err;

    EVP_PKEY_CTX_free(pctx);

    pctx = EVP_PKEY_CTX_new(ekey, NULL);

    if (!pctx)

        goto err;

    if (EVP_PKEY_derive_init(pctx) <= 0)

        goto err;

    kari->pctx = pctx;

    rv = 1;

 err:

    if (!rv && pctx)

        EVP_PKEY_CTX_free(pctx);

    if (ekey)

        EVP_PKEY_free(ekey);

    return rv;

}

/* Initialise a ktri based on passed certificate and key */

int cms_RecipientInfo_kari_init(CMS_RecipientInfo *ri, X509 *recip,

                                EVP_PKEY *pk, unsigned int flags)

{

    CMS_KeyAgreeRecipientInfo *kari;

    CMS_RecipientEncryptedKey *rek = NULL;

    ri->d.kari = M_ASN1_new_of(CMS_KeyAgreeRecipientInfo);

    if (!ri->d.kari)

        return 0;

    ri->type = CMS_RECIPINFO_AGREE;

    kari = ri->d.kari;

    kari->version = 3;

    rek = M_ASN1_new_of(CMS_RecipientEncryptedKey);

    if (!sk_CMS_RecipientEncryptedKey_push(kari->recipientEncryptedKeys, rek)) {

        M_ASN1_free_of(rek, CMS_RecipientEncryptedKey);

        return 0;

    }

    if (flags & CMS_USE_KEYID) {

        rek->rid->type = CMS_REK_KEYIDENTIFIER;

        rek->rid->d.rKeyId = M_ASN1_new_of(CMS_RecipientKeyIdentifier);

        if (rek->rid->d.rKeyId == NULL)

            return 0;

        if (!cms_set1_keyid(&rek->rid->d.rKeyId->subjectKeyIdentifier, recip))

            return 0;

    } else {

        rek->rid->type = CMS_REK_ISSUER_SERIAL;

        if (!cms_set1_ias(&rek->rid->d.issuerAndSerialNumber, recip))

            return 0;

    }

    /* Create ephemeral key */

    if (!cms_kari_create_ephemeral_key(kari, pk))

        return 0;

    CRYPTO_add(&pk->references, 1, CRYPTO_LOCK_EVP_PKEY);

    rek->pkey = pk;

    return 1;

}

static int cms_wrap_init(CMS_KeyAgreeRecipientInfo *kari,

                         const EVP_CIPHER *cipher)

{

    EVP_CIPHER_CTX *ctx = &kari->ctx;

    const EVP_CIPHER *kekcipher;

    int keylen = EVP_CIPHER_key_length(cipher);

    /* If a suitable wrap algorithm is already set nothing to do */

    kekcipher = EVP_CIPHER_CTX_cipher(ctx);

    if (kekcipher) {

        if (EVP_CIPHER_CTX_mode(ctx) != EVP_CIPH_WRAP_MODE)

            return 0;

        return 1;

    }

    /*

     * Pick a cipher based on content encryption cipher. If it is DES3 use

     * DES3 wrap otherwise use AES wrap similar to key size.

     */

#ifndef OPENSSL_NO_DES

    if (EVP_CIPHER_type(cipher) == NID_des_ede3_cbc)

        kekcipher = EVP_des_ede3_wrap();

    else

#endif

    if (keylen <= 16)

        kekcipher = EVP_aes_128_wrap();

    else if (keylen <= 24)

        kekcipher = EVP_aes_192_wrap();

    else

        kekcipher = EVP_aes_256_wrap();

    return EVP_EncryptInit_ex(ctx, kekcipher, NULL, NULL, NULL);

}

/* Encrypt content key in key agreement recipient info */

int cms_RecipientInfo_kari_encrypt(CMS_ContentInfo *cms,

                                   CMS_RecipientInfo *ri)

{

    CMS_KeyAgreeRecipientInfo *kari;

    CMS_EncryptedContentInfo *ec;

    CMS_RecipientEncryptedKey *rek;

    STACK_OF(CMS_RecipientEncryptedKey) *reks;

    int i;

    if (ri->type != CMS_RECIPINFO_AGREE) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_ENCRYPT, CMS_R_NOT_KEY_AGREEMENT);

        return 0;

    }

    kari = ri->d.kari;

    reks = kari->recipientEncryptedKeys;

    ec = cms->d.envelopedData->encryptedContentInfo;

    /* Initialise wrap algorithm parameters */

    if (!cms_wrap_init(kari, ec->cipher))

        return 0;

    /*

     * If no orignator key set up initialise for ephemeral key the public key

     * ASN1 structure will set the actual public key value.

     */

    if (kari->originator->type == -1) {

        CMS_OriginatorIdentifierOrKey *oik = kari->originator;

        oik->type = CMS_OIK_PUBKEY;

        oik->d.originatorKey = M_ASN1_new_of(CMS_OriginatorPublicKey);

        if (!oik->d.originatorKey)

            return 0;

    }

    /* Initialise KDF algorithm */

    if (!cms_env_asn1_ctrl(ri, 0))

        return 0;

    /* For each rek, derive KEK, encrypt CEK */

    for (i = 0; i < sk_CMS_RecipientEncryptedKey_num(reks); i++) {

        unsigned char *enckey;

        size_t enckeylen;

        rek = sk_CMS_RecipientEncryptedKey_value(reks, i);

        if (EVP_PKEY_derive_set_peer(kari->pctx, rek->pkey) <= 0)

            return 0;

        if (!cms_kek_cipher(&enckey, &enckeylen, ec->key, ec->keylen,

                            kari, 1))

            return 0;

        ASN1_STRING_set0(rek->encryptedKey, enckey, enckeylen);

    }

    return 1;

}