/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 *    Copyright 2020 (c) Wind River Systems, Inc.
 *    Copyright 2020 (c) basysKom GmbH
 *    Copyright 2025 (c) o6 Automation GmbH (Author: Julius Pfrommer)
 */

#include <open62541/plugin/securitypolicy_default.h>
#include <open62541/util.h>

#if defined(UA_ENABLE_ENCRYPTION_OPENSSL) || defined(UA_ENABLE_ENCRYPTION_LIBRESSL)

#include "securitypolicy_common.h"

#include <openssl/x509.h>
#include <openssl/rand.h>

#define UA_SECURITYPOLICY_BASIC256SHA1_RSAPADDING_LEN                42
#define UA_SECURITYPOLICY_BASIC256_SYM_ENCRYPTION_KEY_LENGTH         32
#define UA_SECURITYPOLICY_BASIC256_SYM_ENCRYPTION_BLOCK_SIZE         16
#define UA_SECURITYPOLICY_BASIC256_SYM_SIGNING_KEY_LENGTH            24
#define UA_SHA1_LENGTH                                               20

static UA_StatusCode
createSigningRequest_sp_basic256(UA_SecurityPolicy *securityPolicy,
                                 const UA_String *subjectName,
                                 const UA_ByteString *nonce,
                                 const UA_KeyValueMap *params,
                                 UA_ByteString *csr,
                                 UA_ByteString *newPrivateKey) {
    if(securityPolicy == NULL || csr == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;

    if(securityPolicy->policyContext == NULL)
        return UA_STATUSCODE_BADINTERNALERROR;

    openssl_PolicyContext *pc =
            (openssl_PolicyContext *) securityPolicy->policyContext;

    return UA_OpenSSL_CreateSigningRequest(pc->localPrivateKey, &pc->csrLocalPrivateKey,
                                           securityPolicy, subjectName, nonce,
                                           csr, newPrivateKey);
}

/* create the channel context */

static UA_StatusCode
Basic256_New_Context(const UA_SecurityPolicy * securityPolicy,
                                      const UA_ByteString *     remoteCertificate,
                                      void **                   channelContext) {
    if(securityPolicy == NULL || remoteCertificate == NULL || channelContext == NULL)
        return UA_STATUSCODE_BADINTERNALERROR;

    openssl_ChannelContext * context = (openssl_ChannelContext *)
        UA_malloc(sizeof(openssl_ChannelContext));
    if(context == NULL)
        return UA_STATUSCODE_BADOUTOFMEMORY;

    UA_ByteString_init(&context->localSymSigningKey);
    UA_ByteString_init(&context->localSymEncryptingKey);
    UA_ByteString_init(&context->localSymIv);
    UA_ByteString_init(&context->remoteSymSigningKey);
    UA_ByteString_init(&context->remoteSymEncryptingKey);
    UA_ByteString_init(&context->remoteSymIv);

    UA_StatusCode retval = UA_copyCertificate(&context->remoteCertificate,
                                              remoteCertificate);
    if(retval != UA_STATUSCODE_GOOD) {
        UA_free (context);
        return retval;
    }

    /* decode to X509 */
    context->remoteCertificateX509 =
        UA_OpenSSL_LoadCertificate(&context->remoteCertificate, EVP_PKEY_RSA);
    if(context->remoteCertificateX509 == NULL) {
        UA_ByteString_clear (&context->remoteCertificate);
        UA_free (context);
        return UA_STATUSCODE_BADCERTIFICATECHAININCOMPLETE;
    }

    *channelContext = context;

    return UA_STATUSCODE_GOOD;
}

static void
Basic256_Delete_Context(const UA_SecurityPolicy *policy,
                        void *channelContext) {
    if(channelContext == NULL)
        return;
    openssl_ChannelContext *cc = (openssl_ChannelContext *) channelContext;
    X509_free(cc->remoteCertificateX509);
    UA_ByteString_clear(&cc->remoteCertificate);
    UA_ByteString_clear(&cc->localSymSigningKey);
    UA_ByteString_clear(&cc->localSymEncryptingKey);
    UA_ByteString_clear(&cc->localSymIv);
    UA_ByteString_clear(&cc->remoteSymSigningKey);
    UA_ByteString_clear(&cc->remoteSymEncryptingKey);
    UA_ByteString_clear(&cc->remoteSymIv);
    UA_free(cc);
}

/* Generates a thumbprint for the specified certificate */

static UA_StatusCode
UA_Asy_Basic256_makeCertificateThumbprint(const UA_SecurityPolicy * securityPolicy,
                                          const UA_ByteString *     certificate,
                                          UA_ByteString *           thumbprint) {
    return UA_Openssl_X509_GetCertificateThumbprint (certificate, thumbprint, false);
}

static size_t
UA_AsySig_Basic256_getRemoteSignatureSize(const UA_SecurityPolicy *policy,
                                          const void *channelContext) {
    if(channelContext == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    const openssl_ChannelContext *cc =
        (const openssl_ChannelContext *) channelContext;
    UA_Int32 keyLen = 0;
    UA_Openssl_RSA_Public_GetKeyLength(cc->remoteCertificateX509, &keyLen);
    return (size_t) keyLen;
}

static size_t
UA_AsySig_Basic256_getLocalSignatureSize(const UA_SecurityPolicy *policy,
                                         const void *channelContext) {
    if (channelContext == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    const openssl_PolicyContext *pc =
        (const openssl_PolicyContext*)policy->policyContext;
    UA_Int32 keyLen = 0;
    UA_Openssl_RSA_Private_GetKeyLength (pc->localPrivateKey, &keyLen);
    return (size_t) keyLen;
}

static UA_StatusCode
UA_AsySig_Basic256_Verify(const UA_SecurityPolicy *policy, void *channelContext,
                          const UA_ByteString *message,
                          const UA_ByteString *signature) {
    if(message == NULL || signature == NULL || channelContext == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    openssl_ChannelContext * cc = (openssl_ChannelContext *) channelContext;
    return UA_OpenSSL_RSA_PKCS1_V15_SHA1_Verify(message, cc->remoteCertificateX509,
                                                signature);
}

static UA_StatusCode
UA_AsySig_Basic256_Sign(const UA_SecurityPolicy *policy,
                        void *channelContext, const UA_ByteString *message,
                        UA_ByteString *signature) {
    if(channelContext == NULL || message == NULL || signature == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    const openssl_PolicyContext *pc =
        (const openssl_PolicyContext*)policy->policyContext;
    return UA_Openssl_RSA_PKCS1_V15_SHA1_Sign(message, pc->localPrivateKey, signature);
}

static size_t
UA_AsymEn_Basic256_getRemotePlainTextBlockSize(const UA_SecurityPolicy *policy,
                                               const void *channelContext) {
    if(channelContext == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    const openssl_ChannelContext *cc =
        (const openssl_ChannelContext *) channelContext;
    UA_Int32 keyLen = 0;
    UA_StatusCode retval =
        UA_Openssl_RSA_Public_GetKeyLength(cc->remoteCertificateX509, &keyLen);
    if(retval != UA_STATUSCODE_GOOD ||
       keyLen <= (UA_Int32)UA_SECURITYPOLICY_BASIC256SHA1_RSAPADDING_LEN)
        return 0;
    return (size_t) keyLen - UA_SECURITYPOLICY_BASIC256SHA1_RSAPADDING_LEN;
}

static size_t
UA_AsymEn_Basic256_getRemoteBlockSize(const UA_SecurityPolicy *policy,
                                      const void *channelContext) {
    if (channelContext == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    const openssl_ChannelContext *cc =
        (const openssl_ChannelContext *) channelContext;
    UA_Int32 keyLen = 0;
    UA_Openssl_RSA_Public_GetKeyLength(cc->remoteCertificateX509, &keyLen);
    return (size_t) keyLen;
}

static size_t
UA_AsymEn_Basic256_getRemoteKeyLength(const UA_SecurityPolicy *policy,
                                      const void *channelContext) {
    if(channelContext == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    const openssl_ChannelContext *cc =
        (const openssl_ChannelContext *) channelContext;
    UA_Int32 keyLen = 0;
    UA_Openssl_RSA_Public_GetKeyLength(cc->remoteCertificateX509, &keyLen);
    return (size_t) keyLen * 8;
}

static size_t
UA_AsymEn_Basic256_getLocalKeyLength(const UA_SecurityPolicy *policy,
                                     const void *channelContext) {
    if (channelContext == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    const openssl_PolicyContext *pc =
        (const openssl_PolicyContext*)policy->policyContext;
    UA_Int32 keyLen = 0;
    UA_Openssl_RSA_Private_GetKeyLength(pc->localPrivateKey, &keyLen);
    return (size_t) keyLen * 8;
}

static UA_StatusCode
UA_AsymEn_Basic256_Decrypt(const UA_SecurityPolicy *policy,
                           void *channelContext, UA_ByteString *data) {
    if(data == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    const openssl_PolicyContext *pc =
        (const openssl_PolicyContext*)policy->policyContext;
    return UA_Openssl_RSA_Oaep_Decrypt(data, pc->localPrivateKey);
}

static UA_StatusCode
UA_AsymEn_Basic256_Encrypt(const UA_SecurityPolicy *policy,
                           void *channelContext, UA_ByteString *data) {
    if(channelContext == NULL || data == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    openssl_ChannelContext * cc = (openssl_ChannelContext *) channelContext;
    return UA_Openssl_RSA_OAEP_Encrypt(data, UA_SECURITYPOLICY_BASIC256SHA1_RSAPADDING_LEN,
                                       cc->remoteCertificateX509);
}

static UA_StatusCode
UA_Sym_Basic256_generateNonce(const UA_SecurityPolicy *policy,
                              void *channelContext, UA_ByteString *out) {
    UA_Int32 rc = RAND_bytes(out->data, (int) out->length);
    if(rc != 1)
        return UA_STATUSCODE_BADUNEXPECTEDERROR;
    return UA_STATUSCODE_GOOD;
}

static UA_StatusCode
UA_Sym_Basic256_generateKey(const UA_SecurityPolicy *policy,
                            void *channelContext, const UA_ByteString *secret,
                            const UA_ByteString *seed, UA_ByteString *out) {
    return UA_Openssl_Random_Key_PSHA1_Derive(secret, seed, out);
}

static size_t
UA_SymEn_Basic256_getLocalKeyLength(const UA_SecurityPolicy *policy,
                                    const void *channelContext) {
    /* 32 bytes 256 bits */
    return UA_SECURITYPOLICY_BASIC256_SYM_ENCRYPTION_KEY_LENGTH;
}

static size_t
UA_SymEn_Basic256_getBlockSize(const UA_SecurityPolicy *policy,
                               const void *channelContext) {
    return UA_SECURITYPOLICY_BASIC256_SYM_ENCRYPTION_BLOCK_SIZE;
}

static size_t
UA_SymEn_Basic256_getRemoteKeyLength(const UA_SecurityPolicy *policy,
                                     const void *channelContext) {
    /* 32 bytes 256 bits */
    return UA_SECURITYPOLICY_BASIC256_SYM_ENCRYPTION_KEY_LENGTH;
}

static UA_StatusCode
UA_SymEn_Basic256_Encrypt(const UA_SecurityPolicy *policy,
                          void *channelContext, UA_ByteString *data) {
    if(channelContext == NULL || data == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    openssl_ChannelContext * cc = (openssl_ChannelContext *) channelContext;
    return UA_OpenSSL_AES_256_CBC_Encrypt(&cc->localSymIv,
                                          &cc->localSymEncryptingKey, data);
}

static UA_StatusCode
UA_SymEn_Basic256_Decrypt(const UA_SecurityPolicy *policy,
                          void *channelContext, UA_ByteString *data) {
    if(channelContext == NULL || data == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    openssl_ChannelContext * cc = (openssl_ChannelContext *) channelContext;
    return UA_OpenSSL_AES_256_CBC_Decrypt(&cc->remoteSymIv,
                                          &cc->remoteSymEncryptingKey, data);
}

static size_t
UA_SymSig_Basic256_getKeyLength(const UA_SecurityPolicy *policy,
                                const void *channelContext) {
    return UA_SECURITYPOLICY_BASIC256_SYM_SIGNING_KEY_LENGTH;
}

static size_t
UA_SymSig_Basic256_getSignatureSize (const UA_SecurityPolicy *policy,
                                     const void *channelContext) {
    return UA_SHA1_LENGTH;
}

static UA_StatusCode
UA_SymSig_Basic256_Verify(const UA_SecurityPolicy *policy, void *channelContext,
                          const UA_ByteString *message,
                          const UA_ByteString *signature) {
    if(channelContext == NULL || message == NULL || signature == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    openssl_ChannelContext * cc = (openssl_ChannelContext *) channelContext;
    return UA_OpenSSL_HMAC_SHA1_Verify (message, &cc->remoteSymSigningKey,
                                        signature);
}

static UA_StatusCode
UA_SymSig_Basic256_Sign(const UA_SecurityPolicy *policy,
                        void *channelContext, const UA_ByteString *message,
                        UA_ByteString *signature) {
    if(channelContext == NULL || message == NULL || signature == NULL)
        return UA_STATUSCODE_BADINVALIDARGUMENT;
    openssl_ChannelContext * cc = (openssl_ChannelContext *) channelContext;
    return UA_OpenSSL_HMAC_SHA1_Sign(message, &cc->localSymSigningKey, signature);
}

UA_StatusCode
UA_SecurityPolicy_Basic256(UA_SecurityPolicy *sp,
                           const UA_ByteString localCertificate,
                           const UA_ByteString localPrivateKey,
                           const UA_Logger *logger) {
    UA_LOG_WARNING(logger, UA_LOGCATEGORY_SECURITYPOLICY,
                   "!! WARNING !! The Basic256 SecurityPolicy is unsecure. "
                   "There are known attacks that break the encryption.");

    memset(sp, 0, sizeof(UA_SecurityPolicy));
    sp->logger = logger;
    sp->policyUri = UA_STRING("http://opcfoundation.org/UA/SecurityPolicy#Basic256\0");
    sp->certificateGroupId = UA_NS0ID(SERVERCONFIGURATION_CERTIFICATEGROUPS_DEFAULTAPPLICATIONGROUP);
    sp->certificateTypeId = UA_NS0ID(RSAMINAPPLICATIONCERTIFICATETYPE);
    sp->securityLevel = 0;
    sp->policyType = UA_SECURITYPOLICYTYPE_RSA;

    /* Asymmetric Signature */
    UA_SecurityPolicySignatureAlgorithm *asymSig = &sp->asymSignatureAlgorithm;
    asymSig->uri = UA_STRING("http://www.w3.org/2000/09/xmldsig#rsa-sha1\0");
    asymSig->verify = UA_AsySig_Basic256_Verify;
    asymSig->sign = UA_AsySig_Basic256_Sign;
    asymSig->getLocalSignatureSize = UA_AsySig_Basic256_getLocalSignatureSize;
    asymSig->getRemoteSignatureSize = UA_AsySig_Basic256_getRemoteSignatureSize;

    /* Asymmetric Encryption */
    UA_SecurityPolicyEncryptionAlgorithm *asymEnc = &sp->asymEncryptionAlgorithm;
    asymEnc->uri = UA_STRING("http://www.w3.org/2001/04/xmlenc#rsa-oaep\0");
    asymEnc->encrypt = UA_AsymEn_Basic256_Encrypt;
    asymEnc->decrypt = UA_AsymEn_Basic256_Decrypt;
    asymEnc->getLocalKeyLength = UA_AsymEn_Basic256_getLocalKeyLength;
    asymEnc->getRemoteKeyLength = UA_AsymEn_Basic256_getRemoteKeyLength;
    asymEnc->getRemoteBlockSize = UA_AsymEn_Basic256_getRemoteBlockSize;
    asymEnc->getRemotePlainTextBlockSize = UA_AsymEn_Basic256_getRemotePlainTextBlockSize;

    /* Symmetric Signature */
    UA_SecurityPolicySignatureAlgorithm *symSig = &sp->symSignatureAlgorithm;
    symSig->uri = UA_STRING("http://www.w3.org/2000/09/xmldsig#hmac-sha1\0");
    symSig->verify = UA_SymSig_Basic256_Verify;
    symSig->sign = UA_SymSig_Basic256_Sign;
    symSig->getLocalSignatureSize = UA_SymSig_Basic256_getSignatureSize;
    symSig->getRemoteSignatureSize = UA_SymSig_Basic256_getSignatureSize;
    symSig->getLocalKeyLength = UA_SymSig_Basic256_getKeyLength;
    symSig->getRemoteKeyLength = UA_SymSig_Basic256_getKeyLength;

    /* Symmetric Encryption */
    UA_SecurityPolicyEncryptionAlgorithm *symEnc = &sp->symEncryptionAlgorithm;
    symEnc->uri = UA_STRING("http://www.w3.org/2001/04/xmlenc#aes256-cbc\0");
    symEnc->encrypt = UA_SymEn_Basic256_Encrypt;
    symEnc->decrypt = UA_SymEn_Basic256_Decrypt;
    symEnc->getLocalKeyLength = UA_SymEn_Basic256_getLocalKeyLength;
    symEnc->getRemoteKeyLength = UA_SymEn_Basic256_getRemoteKeyLength;
    symEnc->getRemoteBlockSize = UA_SymEn_Basic256_getBlockSize;
    symEnc->getRemotePlainTextBlockSize = UA_SymEn_Basic256_getBlockSize;

    /* Use the same signature algorithm as the asymmetric component for
     * certificate signing (see standard) */
    sp->certSignatureAlgorithm = sp->asymSignatureAlgorithm;

    /* Direct Method Pointers */
    sp->newChannelContext = Basic256_New_Context;
    sp->deleteChannelContext = Basic256_Delete_Context;
    sp->setLocalSymEncryptingKey = UA_OpenSSL_setLocalSymEncryptingKey_generic;
    sp->setLocalSymSigningKey = UA_OpenSSL_setLocalSymSigningKey_generic;
    sp->setLocalSymIv = UA_OpenSSL_setLocalSymIv_generic;
    sp->setRemoteSymEncryptingKey = UA_OpenSSL_setRemoteSymEncryptingKey_generic;
    sp->setRemoteSymSigningKey = UA_OpenSSL_setRemoteSymSigningKey_generic;
    sp->setRemoteSymIv = UA_OpenSSL_setRemoteSymIv_generic;
    sp->compareCertificate = UA_OpenSSL_compareCertificate_generic;
    sp->generateKey = UA_Sym_Basic256_generateKey;
    sp->generateNonce = UA_Sym_Basic256_generateNonce;
    sp->nonceLength = 32;
    sp->makeCertThumbprint = UA_Asy_Basic256_makeCertificateThumbprint;
    sp->compareCertThumbprint = UA_OpenSSL_SecurityPolicy_compareCertThumbprint_generic;
    sp->updateCertificate = UA_OpenSSL_SecurityPolicy_updateCertificate_generic;
    sp->createSigningRequest = createSigningRequest_sp_basic256;
    sp->clear = UA_OpenSSL_Policy_clearContext_generic;

    /* Parse the certificate */
    UA_Openssl_Init();
    UA_StatusCode res =
        UA_OpenSSL_LoadLocalCertificate(&localCertificate, &sp->localCertificate, EVP_PKEY_RSA);
    if(res != UA_STATUSCODE_GOOD)
        return res;

    /* Create the policy context */
    res = UA_OpenSSL_Policy_newContext_generic(sp, localPrivateKey, EVP_PKEY_RSA, logger);
    if(res != UA_STATUSCODE_GOOD) {
        UA_ByteString_clear(&sp->localCertificate);
        return res;
    }

    return UA_STATUSCODE_GOOD;
}

#endif