/*

 * Copyright 2008-2021 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include "internal/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 "crypto/evp.h"

#include "crypto/asn1.h"

#include "cms_local.h"

/* CMS EncryptedData Utilities */

/* Return BIO based on EncryptedContentInfo and key */

BIO *ossl_cms_EncryptedContent_init_bio(CMS_EncryptedContentInfo *ec,

                                        const CMS_CTX *cms_ctx)

{

    BIO *b;

    EVP_CIPHER_CTX *ctx;

    EVP_CIPHER *fetched_ciph = NULL;

    const EVP_CIPHER *cipher = NULL;

    X509_ALGOR *calg = ec->contentEncryptionAlgorithm;

    evp_cipher_aead_asn1_params aparams;

    unsigned char iv[EVP_MAX_IV_LENGTH], *piv = NULL;

    unsigned char *tkey = NULL;

    int len;

    int ivlen = 0;

    size_t tkeylen = 0;

    int ok = 0;

    int enc, keep_key = 0;

    OSSL_LIB_CTX *libctx = ossl_cms_ctx_get0_libctx(cms_ctx);

    const char *propq = ossl_cms_ctx_get0_propq(cms_ctx);

    enc = ec->cipher ? 1 : 0;

    b = BIO_new(BIO_f_cipher());

    if (b == NULL) {

        ERR_raise(ERR_LIB_CMS, ERR_R_BIO_LIB);

        return NULL;

    }

    BIO_get_cipher_ctx(b, &ctx);

    (void)ERR_set_mark();

    if (enc) {

        cipher = ec->cipher;

        /*

         * If not keeping key set cipher to NULL so subsequent calls decrypt.

         */

        if (ec->key != NULL)

            ec->cipher = NULL;

    } else {

        cipher = EVP_get_cipherbyobj(calg->algorithm);

    }

    if (cipher != NULL) {

        fetched_ciph = EVP_CIPHER_fetch(libctx, EVP_CIPHER_get0_name(cipher),

                                        propq);

        if (fetched_ciph != NULL)

            cipher = fetched_ciph;

    }

    if (cipher == NULL) {

        (void)ERR_clear_last_mark();

        ERR_raise(ERR_LIB_CMS, CMS_R_UNKNOWN_CIPHER);

        goto err;

    }

    (void)ERR_pop_to_mark();

    if (EVP_CipherInit_ex(ctx, cipher, NULL, NULL, NULL, enc) <= 0) {

        ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_INITIALISATION_ERROR);

        goto err;

    }

    if (enc) {

        calg->algorithm = OBJ_nid2obj(EVP_CIPHER_CTX_get_type(ctx));

        if (calg->algorithm == NULL || calg->algorithm->nid == NID_undef) {

            ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_CONTENT_ENCRYPTION_ALGORITHM);

            goto err;

        }

        /* Generate a random IV if we need one */

        ivlen = EVP_CIPHER_CTX_get_iv_length(ctx);

        if (ivlen < 0) {

            ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);

            goto err;

        }

        if (ivlen > 0) {

            if (RAND_bytes_ex(libctx, iv, ivlen, 0) <= 0)

                goto err;

            piv = iv;

        }

    } else {

        if (evp_cipher_asn1_to_param_ex(ctx, calg->parameter, &aparams) <= 0) {

            ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);

            goto err;

        }

        if ((EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER)) {

            piv = aparams.iv;

            if (ec->taglen > 0

                    && EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG,

                                           ec->taglen, ec->tag) <= 0) {

                ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_AEAD_SET_TAG_ERROR);

                goto err;

            }

        }

    }

    len = EVP_CIPHER_CTX_get_key_length(ctx);

    if (len <= 0)

        goto err;

    tkeylen = (size_t)len;

    /* Generate random session key */

    if (!enc || !ec->key) {

        tkey = OPENSSL_malloc(tkeylen);

        if (tkey == NULL)

            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) {

                ERR_raise(ERR_LIB_CMS, CMS_R_INVALID_KEY_LENGTH);

                goto err;

            } else {

                /* Use random key */

                OPENSSL_clear_free(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) {

        ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_INITIALISATION_ERROR);

        goto err;

    }

    if (enc) {

        calg->parameter = ASN1_TYPE_new();

        if (calg->parameter == NULL) {

            ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);

            goto err;

        }

        if ((EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER)) {

            memcpy(aparams.iv, piv, ivlen);

            aparams.iv_len = ivlen;

            aparams.tag_len = EVP_CIPHER_CTX_get_tag_length(ctx);

            if (aparams.tag_len <= 0)

                goto err;

        }

        if (evp_cipher_param_to_asn1_ex(ctx, calg->parameter, &aparams) <= 0) {

            ERR_raise(ERR_LIB_CMS, 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:

    EVP_CIPHER_free(fetched_ciph);

    if (!keep_key || !ok) {

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

        ec->key = NULL;

    }

    OPENSSL_clear_free(tkey, tkeylen);

    if (ok)

        return b;

    BIO_free(b);

    return NULL;

}

int ossl_cms_EncryptedContent_init(CMS_EncryptedContentInfo *ec,

                                   const EVP_CIPHER *cipher,

                                   const unsigned char *key, size_t keylen,

                                   const CMS_CTX *cms_ctx)

{

    ec->cipher = cipher;

    if (key) {

        if ((ec->key = OPENSSL_malloc(keylen)) == NULL)

            return 0;

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

    }

    ec->keylen = keylen;

    if (cipher != NULL)

        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) {

        ERR_raise(ERR_LIB_CMS, CMS_R_NO_KEY);

        return 0;

    }

    if (ciph) {

        cms->d.encryptedData = M_ASN1_new_of(CMS_EncryptedData);

        if (!cms->d.encryptedData) {

            ERR_raise(ERR_LIB_CMS, ERR_R_ASN1_LIB);

            return 0;

        }

        cms->contentType = OBJ_nid2obj(NID_pkcs7_encrypted);

        cms->d.encryptedData->version = 0;

    } else if (OBJ_obj2nid(cms->contentType) != NID_pkcs7_encrypted) {

        ERR_raise(ERR_LIB_CMS, CMS_R_NOT_ENCRYPTED_DATA);

        return 0;

    }

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

    return ossl_cms_EncryptedContent_init(ec, ciph, key, keylen,

                                          ossl_cms_get0_cmsctx(cms));

}

BIO *ossl_cms_EncryptedData_init_bio(const CMS_ContentInfo *cms)

{

    CMS_EncryptedData *enc = cms->d.encryptedData;

    if (enc->encryptedContentInfo->cipher && enc->unprotectedAttrs)

        enc->version = 2;

    return ossl_cms_EncryptedContent_init_bio(enc->encryptedContentInfo,

                                              ossl_cms_get0_cmsctx(cms));

}