/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * 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/.
 *
 * This file incorporates work covered by the following license notice:
 *
 *   Licensed to the Apache Software Foundation (ASF) under one or more
 *   contributor license agreements. See the NOTICE file distributed
 *   with this work for additional information regarding copyright
 *   ownership. The ASF licenses this file to you under the Apache
 *   License, Version 2.0 (the "License"); you may not use this file
 *   except in compliance with the License. You may obtain a copy of
 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
 */

#include "nssrenam.h"
#include <cert.h>
#include <secerr.h>
#include <ocsp.h>

#include <sal/config.h>
#include <sal/macros.h>
#include <osl/diagnose.h>
#include "securityenvironment_nssimpl.hxx"
#include <comphelper/servicehelper.hxx>

#include <xmlsec-wrapper.h>

#include <rtl/ustrbuf.hxx>
#include <comphelper/processfactory.hxx>
#include <comphelper/docpasswordrequest.hxx>
#include <biginteger.hxx>
#include <sal/log.hxx>
#include <com/sun/star/task/InteractionHandler.hpp>
#include <vector>
#include <memory>
#include <osl/thread.h>
#include <comphelper/sequence.hxx>

#include "secerror.hxx"

// added for password exception
#include <com/sun/star/security/NoPasswordException.hpp>
namespace csss = ::com::sun::star::security;
using namespace ::com::sun::star::security;
using namespace com::sun::star;
using namespace ::com::sun::star::uno ;
using namespace ::com::sun::star::lang ;
using ::com::sun::star::lang::XMultiServiceFactory ;
using ::com::sun::star::lang::XSingleServiceFactory ;

using ::com::sun::star::xml::crypto::XSecurityEnvironment ;
using ::com::sun::star::security::XCertificate ;

namespace std
{
template <> struct default_delete<PRArenaPool>
{
    void operator()(PRArenaPool* ptr) { PORT_FreeArena(ptr, PR_FALSE); }
};
}

static X509Certificate_NssImpl* NssCertToXCert( CERTCertificate* cert ) ;
static X509Certificate_NssImpl* NssPrivKeyToXCert( SECKEYPrivateKey* ) ;


struct UsageDescription
{
    SECCertificateUsage usage;
    char const* description;

    UsageDescription()
    : usage( certificateUsageCheckAllUsages )
    , description( nullptr )
    {}

    UsageDescription( SECCertificateUsage i_usage, char const* i_description )
    : usage( i_usage )
    , description( i_description )
    {}
};


static char* GetPasswordFunction( PK11SlotInfo* pSlot, PRBool bRetry, void* /*arg*/ )
{
    uno::Reference< uno::XComponentContext > xContext( ::comphelper::getProcessComponentContext() );
    uno::Reference < task::XInteractionHandler2 > xInteractionHandler(
        task::InteractionHandler::createWithParent(xContext, nullptr) );

    task::PasswordRequestMode eMode = bRetry ? task::PasswordRequestMode_PASSWORD_REENTER : task::PasswordRequestMode_PASSWORD_ENTER;
    ::comphelper::DocPasswordRequest* pPasswordRequest = new ::comphelper::DocPasswordRequest(
        ::comphelper::DocPasswordRequestType::Standard, eMode, OUString::createFromAscii(PK11_GetTokenName(pSlot)) );

    uno::Reference< task::XInteractionRequest > xRequest( pPasswordRequest );
    xInteractionHandler->handle( xRequest );

    if ( pPasswordRequest->isPassword() )
    {
        OString aPassword(OUStringToOString(
            pPasswordRequest->getPassword(),
            osl_getThreadTextEncoding()));
        sal_Int32 nLen = aPassword.getLength();
        char* pPassword = static_cast<char*>(PORT_Alloc( nLen+1 ) );
        pPassword[nLen] = 0;
        memcpy( pPassword, aPassword.getStr(), nLen );
        return pPassword;
    }
    return nullptr;
}

SecurityEnvironment_NssImpl::SecurityEnvironment_NssImpl() :
m_pHandler( nullptr ) , m_tSymKeyList() {
    PK11_SetPasswordFunc( GetPasswordFunction ) ;
}

SecurityEnvironment_NssImpl::~SecurityEnvironment_NssImpl() {

    PK11_SetPasswordFunc( nullptr ) ;

    for (auto& slot : m_Slots)
    {
        PK11_FreeSlot(slot);
    }

    if( !m_tSymKeyList.empty()  ) {
        for( auto& symKey : m_tSymKeyList )
            PK11_FreeSymKey( symKey ) ;
    }
}

/* XServiceInfo */
OUString SAL_CALL SecurityEnvironment_NssImpl::getImplementationName() {
    return OUString("com.sun.star.xml.crypto.SecurityEnvironment");
}

/* XServiceInfo */
sal_Bool SAL_CALL SecurityEnvironment_NssImpl::supportsService( const OUString& serviceName) {
    Sequence< OUString > seqServiceNames = getSupportedServiceNames() ;
    const OUString* pArray = seqServiceNames.getConstArray() ;
    for( sal_Int32 i = 0 ; i < seqServiceNames.getLength() ; i ++ ) {
        if( *( pArray + i ) == serviceName )
            return true ;
    }
    return false ;
}

/* XServiceInfo */
Sequence< OUString > SAL_CALL SecurityEnvironment_NssImpl::getSupportedServiceNames() {
    Sequence<OUString> seqServiceNames{ "com.sun.star.xml.crypto.SecurityEnvironment" };
    return seqServiceNames;
}

/* XUnoTunnel */
sal_Int64 SAL_CALL SecurityEnvironment_NssImpl::getSomething( const Sequence< sal_Int8 >& aIdentifier )
{
    if( aIdentifier.getLength() == 16 && 0 == memcmp( getUnoTunnelId().getConstArray(), aIdentifier.getConstArray(), 16 ) ) {
        return sal::static_int_cast<sal_Int64>(reinterpret_cast<sal_uIntPtr>(this));
    }
    return 0 ;
}

/* XUnoTunnel extension */

namespace
{
    class theSecurityEnvironment_NssImplUnoTunnelId  : public rtl::Static< UnoTunnelIdInit, theSecurityEnvironment_NssImplUnoTunnelId > {};
}

const Sequence< sal_Int8>& SecurityEnvironment_NssImpl::getUnoTunnelId() {
    return theSecurityEnvironment_NssImplUnoTunnelId::get().getSeq();
}

OUString SecurityEnvironment_NssImpl::getSecurityEnvironmentInformation()
{
    OUStringBuffer buff;
    for (auto& slot : m_Slots)
    {
        buff.append(OUString::createFromAscii(PK11_GetTokenName(slot)));
        buff.append("\n");
    }
    return buff.makeStringAndClear();
}

void SecurityEnvironment_NssImpl::addCryptoSlot( PK11SlotInfo* aSlot)
{
    PK11_ReferenceSlot(aSlot);
    m_Slots.push_back(aSlot);
}

//Could we have multiple cert dbs?
void SecurityEnvironment_NssImpl::setCertDb( CERTCertDBHandle* aCertDb ) {
    m_pHandler = aCertDb ;
}

void SecurityEnvironment_NssImpl::adoptSymKey( PK11SymKey* aSymKey ) {
    if( aSymKey != nullptr ) {
        //First try to find the key in the list
        if (std::find(m_tSymKeyList.begin(), m_tSymKeyList.end(), aSymKey) != m_tSymKeyList.end())
            return;

        //If we do not find the key in the list, add a new node
        PK11SymKey* symkey = PK11_ReferenceSymKey( aSymKey ) ;
        if( symkey == nullptr )
            throw RuntimeException() ;

        try {
            m_tSymKeyList.push_back( symkey ) ;
        } catch ( Exception& ) {
            PK11_FreeSymKey( symkey ) ;
        }
    }
}

void SecurityEnvironment_NssImpl::updateSlots()
{
    //In case new tokens are present then we can obtain the corresponding slot
    osl::MutexGuard guard(m_mutex);

    m_Slots.clear();
    m_tSymKeyList.clear();

    PK11SlotList * soltList = PK11_GetAllTokens( CKM_INVALID_MECHANISM, PR_FALSE, PR_FALSE, nullptr ) ;
    if( soltList != nullptr )
    {
        for (PK11SlotListElement* soltEle = soltList->head ; soltEle != nullptr; soltEle = soltEle->next)
        {
            PK11SlotInfo * pSlot = soltEle->slot ;

            if(pSlot != nullptr)
            {
                SAL_INFO(
                    "xmlsecurity.xmlsec",
                    "Found a slot: SlotName=" << PK11_GetSlotName(pSlot)
                        << ", TokenName=" << PK11_GetTokenName(pSlot));

//The following code which is commented out checks if a slot, that is a smart card for example, is
//              able to generate a symmetric key of type CKM_DES3_CBC. If this fails then this token
//              will not be used. This key is possibly used for the encryption service. However, all
//              interfaces and services used for public key signature and encryption are not published
//              and the encryption is not used in OOo. Therefore it does not do any harm to remove
//              this code, hence allowing smart cards which cannot generate this type of key.
//
//              By doing this, the encryption may fail if a smart card is being used which does not
//              support this key generation.
//
                PK11SymKey * pSymKey = PK11_KeyGen( pSlot , CKM_DES3_CBC, nullptr, 128, nullptr ) ;
//              if( pSymKey == NULL )
//              {
//                  PK11_FreeSlot( pSlot ) ;
//                  SAL_INFO( "xmlsecurity", "XMLSEC: Error - pSymKey is NULL" );
//                  continue;
//              }
                addCryptoSlot(pSlot);
                PK11_FreeSlot( pSlot ) ;
                pSlot = nullptr;

                if (pSymKey != nullptr)
                {
                    adoptSymKey( pSymKey ) ;
                    PK11_FreeSymKey( pSymKey ) ;
                    pSymKey = nullptr;
                }

            }// end of if(pSlot != NULL)
        }// end of for
    }// end of if( soltList != NULL )
}

Sequence< Reference < XCertificate > >
SecurityEnvironment_NssImpl::getPersonalCertificates()
{
    sal_Int32 length ;
    X509Certificate_NssImpl* xcert ;
    std::list< X509Certificate_NssImpl* > certsList ;

    updateSlots();
    //firstly, we try to find private keys in slot
    for (auto& slot : m_Slots)
    {
        SECKEYPrivateKeyList* priKeyList ;

        if( PK11_NeedLogin(slot ) ) {
            SECStatus nRet = PK11_Authenticate(slot, PR_TRUE, nullptr);
            //PK11_Authenticate may fail in case the a slot has not been initialized.
            //this is the case if the user has a new profile, so that they have never
            //added a personal certificate.
            if( nRet != SECSuccess && PORT_GetError() != SEC_ERROR_IO) {
                throw NoPasswordException();
            }
        }

        priKeyList = PK11_ListPrivateKeysInSlot(slot) ;
        if( priKeyList != nullptr )
        {
            for (SECKEYPrivateKeyListNode* curPri = PRIVKEY_LIST_HEAD(priKeyList);
                !PRIVKEY_LIST_END( curPri, priKeyList ) && curPri != nullptr;
                curPri = PRIVKEY_LIST_NEXT(curPri))
            {
                xcert = NssPrivKeyToXCert( curPri->key ) ;
                if( xcert != nullptr )
                    certsList.push_back( xcert ) ;
            }
            SECKEY_DestroyPrivateKeyList( priKeyList ) ;
        }


    }

    length = certsList.size() ;
    if( length != 0 ) {
        int i = 0;
        Sequence< Reference< XCertificate > > certSeq( length ) ;

        for( const auto& rXCert : certsList ) {
            certSeq[i] = rXCert ;
            ++i;
        }

        return certSeq ;
    }

    return Sequence< Reference < XCertificate > > ();
}

Reference< XCertificate > SecurityEnvironment_NssImpl::getCertificate( const OUString& issuerName, const Sequence< sal_Int8 >& serialNumber )
{
    X509Certificate_NssImpl* xcert = nullptr;

    if( m_pHandler != nullptr ) {
        CERTIssuerAndSN issuerAndSN ;
        CERTCertificate* cert ;
        CERTName* nmIssuer ;
        char* chIssuer ;
        SECItem* derIssuer ;
        std::unique_ptr<PRArenaPool> arena(PORT_NewArena(DER_DEFAULT_CHUNKSIZE));
        if( arena == nullptr )
            throw RuntimeException() ;

        // Create cert info from issue and serial
        OString ostr = OUStringToOString( issuerName , RTL_TEXTENCODING_UTF8 ) ;
        chIssuer = PL_strndup( ostr.getStr(), static_cast<int>(ostr.getLength()) ) ;
        nmIssuer = CERT_AsciiToName( chIssuer ) ;
        if( nmIssuer == nullptr ) {
            PL_strfree( chIssuer ) ;
            return nullptr; // no need for exception cf. i40394
        }

        derIssuer = SEC_ASN1EncodeItem( arena.get(), nullptr, static_cast<void*>(nmIssuer), SEC_ASN1_GET( CERT_NameTemplate ) ) ;
        if( derIssuer == nullptr ) {
            PL_strfree( chIssuer ) ;
            CERT_DestroyName( nmIssuer ) ;
            throw RuntimeException() ;
        }

        memset( &issuerAndSN, 0, sizeof( issuerAndSN ) ) ;

        issuerAndSN.derIssuer.data = derIssuer->data ;
        issuerAndSN.derIssuer.len = derIssuer->len ;

        issuerAndSN.serialNumber.data = reinterpret_cast<unsigned char *>(const_cast<sal_Int8 *>(serialNumber.getConstArray()));
        issuerAndSN.serialNumber.len = serialNumber.getLength() ;

        cert = CERT_FindCertByIssuerAndSN( m_pHandler, &issuerAndSN ) ;
        if( cert != nullptr ) {
            xcert = NssCertToXCert( cert ) ;
        } else {
            xcert = nullptr ;
        }

        PL_strfree( chIssuer ) ;
        CERT_DestroyName( nmIssuer ) ;
        //SECITEM_FreeItem( derIssuer, PR_FALSE ) ;
        CERT_DestroyCertificate( cert ) ;
    } else {
        xcert = nullptr ;
    }

    return xcert ;
}

Sequence< Reference < XCertificate > > SecurityEnvironment_NssImpl::buildCertificatePath( const Reference< XCertificate >& begin ) {
    // Remember the signing certificate.
    m_xSigningCertificate = begin;

    const X509Certificate_NssImpl* xcert ;
    const CERTCertificate* cert ;
    CERTCertList* certChain ;

    Reference< XUnoTunnel > xCertTunnel( begin, UNO_QUERY_THROW ) ;
    xcert = reinterpret_cast<X509Certificate_NssImpl*>(
        sal::static_int_cast<sal_uIntPtr>(xCertTunnel->getSomething( X509Certificate_NssImpl::getUnoTunnelId() ))) ;
    if( xcert == nullptr ) {
        throw RuntimeException() ;
    }

    cert = xcert->getNssCert() ;
    if( cert != nullptr ) {
        int64 timeboundary ;

        //Get the system clock time
        timeboundary = PR_Now() ;

        certChain = CERT_GetCertChainFromCert( const_cast<CERTCertificate*>(cert), timeboundary, certUsageAnyCA ) ;
    } else {
        certChain = nullptr ;
    }

    if( certChain != nullptr ) {
        std::vector<uno::Reference<security::XCertificate>> aCertChain;

        for (CERTCertListNode* node = CERT_LIST_HEAD(certChain); !CERT_LIST_END(node, certChain); node = CERT_LIST_NEXT(node)) {
            X509Certificate_NssImpl* pCert = new X509Certificate_NssImpl();
            if( pCert == nullptr ) {
                CERT_DestroyCertList( certChain ) ;
                throw RuntimeException() ;
            }

            pCert->setCert( node->cert ) ;

            aCertChain.push_back(pCert);
        }

        CERT_DestroyCertList( certChain ) ;

        return comphelper::containerToSequence(aCertChain);
    }

    return Sequence< Reference < XCertificate > >();
}

X509Certificate_NssImpl* SecurityEnvironment_NssImpl::createX509CertificateFromDER(const css::uno::Sequence<sal_Int8>& aDerCertificate)
{
    X509Certificate_NssImpl* pX509Certificate = nullptr;

    if (aDerCertificate.getLength() > 0)
    {
        pX509Certificate = new X509Certificate_NssImpl();
        if (pX509Certificate == nullptr)
            throw RuntimeException();
        pX509Certificate->setRawCert(aDerCertificate);
    }
    return pX509Certificate;
}

Reference<XCertificate> SecurityEnvironment_NssImpl::createCertificateFromRaw(const Sequence< sal_Int8 >& rawCertificate)
{
    return createX509CertificateFromDER(rawCertificate);
}

Reference< XCertificate > SecurityEnvironment_NssImpl::createCertificateFromAscii( const OUString& asciiCertificate )
{
    OString oscert = OUStringToOString( asciiCertificate , RTL_TEXTENCODING_ASCII_US ) ;
    xmlChar* chCert = xmlStrndup( reinterpret_cast<const xmlChar*>(oscert.getStr()), static_cast<int>(oscert.getLength()) ) ;
    int certSize = xmlSecBase64Decode( chCert, reinterpret_cast<xmlSecByte*>(chCert), xmlStrlen( chCert ) ) ;
    if (certSize > 0)
    {
        Sequence< sal_Int8 > rawCert(certSize) ;
        for (int i = 0 ; i < certSize; ++i)
            rawCert[i] = *( chCert + i ) ;

        xmlFree( chCert ) ;

        return createCertificateFromRaw( rawCert ) ;
    }
    else
    {
        return nullptr;
    }
}

sal_Int32 SecurityEnvironment_NssImpl ::
verifyCertificate( const Reference< csss::XCertificate >& aCert,
                   const Sequence< Reference< csss::XCertificate > >&  intermediateCerts )
{
    sal_Int32 validity = csss::CertificateValidity::INVALID;
    const X509Certificate_NssImpl* xcert ;
    const CERTCertificate* cert ;
    ::std::vector<CERTCertificate*> vecTmpNSSCertificates;
    Reference< XUnoTunnel > xCertTunnel( aCert, UNO_QUERY_THROW ) ;

    SAL_INFO("xmlsecurity.xmlsec", "Start verification of certificate: " << aCert->getSubjectName());

    xcert = reinterpret_cast<X509Certificate_NssImpl*>(
       sal::static_int_cast<sal_uIntPtr>(xCertTunnel->getSomething( X509Certificate_NssImpl::getUnoTunnelId() ))) ;
    if( xcert == nullptr ) {
        throw RuntimeException() ;
    }

    //CERT_PKIXVerifyCert does not take a db as argument. It will therefore
    //internally use CERT_GetDefaultCertDB
    //Make sure m_pHandler is the default DB
    OSL_ASSERT(m_pHandler == CERT_GetDefaultCertDB());
    CERTCertDBHandle * certDb = m_pHandler != nullptr ? m_pHandler : CERT_GetDefaultCertDB();
    cert = xcert->getNssCert() ;
    if( cert != nullptr )
    {

        //prepare the intermediate certificates
        for (sal_Int32 i = 0; i < intermediateCerts.getLength(); i++)
        {
            Sequence<sal_Int8> der = intermediateCerts[i]->getEncoded();
            SECItem item;
            item.type = siBuffer;
            item.data = reinterpret_cast<unsigned char*>(der.getArray());
            item.len = der.getLength();

            CERTCertificate* certTmp = CERT_NewTempCertificate(certDb, &item,
                                           nullptr     /* nickname */,
                                           PR_FALSE /* isPerm */,
                                           PR_TRUE  /* copyDER */);
             if (!certTmp)
             {
                 SAL_INFO("xmlsecurity.xmlsec", "Failed to add a temporary certificate: " << intermediateCerts[i]->getIssuerName());

             }
             else
             {
                 SAL_INFO("xmlsecurity.xmlsec", "Added temporary certificate: " <<
                          (certTmp->subjectName ? certTmp->subjectName : ""));
                 vecTmpNSSCertificates.push_back(certTmp);
             }
        }


        SECStatus status ;

        CERTVerifyLog log;
        log.arena = PORT_NewArena(512);
        log.head = log.tail = nullptr;
        log.count = 0;

        CERT_EnableOCSPChecking(certDb);
        CERT_DisableOCSPDefaultResponder(certDb);
        CERTValOutParam cvout[5];
        CERTValInParam cvin[3];
        int ncvinCount=0;

#if ( NSS_VMAJOR > 3 ) || ( NSS_VMAJOR == 3 && NSS_VMINOR > 12 ) || ( NSS_VMAJOR == 3 && NSS_VMINOR == 12 && NSS_VPATCH > 0 )
        cvin[ncvinCount].type = cert_pi_useAIACertFetch;
        cvin[ncvinCount].value.scalar.b = PR_TRUE;
        ncvinCount++;
#endif

        PRUint64 revFlagsLeaf[2];
        PRUint64 revFlagsChain[2];
        CERTRevocationFlags rev;
        rev.leafTests.number_of_defined_methods = 2;
        rev.leafTests.cert_rev_flags_per_method = revFlagsLeaf;
        //the flags are defined in cert.h
        //We check both leaf and chain.
        //It is enough if one revocation method has fresh info,
        //but at least one must have some. Otherwise validation fails.
        //!!! using leaf test and CERT_REV_MI_REQUIRE_SOME_FRESH_INFO_AVAILABLE
        // when validating a root certificate will result in "revoked". Usually
        //there is no revocation information available for the root cert because
        //it must be trusted anyway and it does itself issue revocation information.
        //When we use the flag here and OOo shows the certification path then the root
        //cert is invalid while all other can be valid. It would probably best if
        //this interface method returned the whole chain.
        //Otherwise we need to check if the certificate is self-signed and if it is
        //then not use the flag when doing the leaf-test.
        rev.leafTests.cert_rev_flags_per_method[cert_revocation_method_crl] =
            CERT_REV_M_TEST_USING_THIS_METHOD
            | CERT_REV_M_IGNORE_IMPLICIT_DEFAULT_SOURCE;
        rev.leafTests.cert_rev_flags_per_method[cert_revocation_method_ocsp] =
            CERT_REV_M_TEST_USING_THIS_METHOD
            | CERT_REV_M_IGNORE_IMPLICIT_DEFAULT_SOURCE;
        rev.leafTests.number_of_preferred_methods = 0;
        rev.leafTests.preferred_methods = nullptr;
        rev.leafTests.cert_rev_method_independent_flags =
            CERT_REV_MI_TEST_ALL_LOCAL_INFORMATION_FIRST;

        rev.chainTests.number_of_defined_methods = 2;
        rev.chainTests.cert_rev_flags_per_method = revFlagsChain;
        rev.chainTests.cert_rev_flags_per_method[cert_revocation_method_crl] =
            CERT_REV_M_TEST_USING_THIS_METHOD
            | CERT_REV_M_IGNORE_IMPLICIT_DEFAULT_SOURCE;
        rev.chainTests.cert_rev_flags_per_method[cert_revocation_method_ocsp] =
            CERT_REV_M_TEST_USING_THIS_METHOD
            | CERT_REV_M_IGNORE_IMPLICIT_DEFAULT_SOURCE;
        rev.chainTests.number_of_preferred_methods = 0;
        rev.chainTests.preferred_methods = nullptr;
        rev.chainTests.cert_rev_method_independent_flags =
            CERT_REV_MI_TEST_ALL_LOCAL_INFORMATION_FIRST;


        cvin[ncvinCount].type = cert_pi_revocationFlags;
        cvin[ncvinCount].value.pointer.revocation = &rev;
        ncvinCount++;
        // does not work, not implemented yet in 3.12.4
//         cvin[ncvinCount].type = cert_pi_keyusage;
//         cvin[ncvinCount].value.scalar.ui = KU_DIGITAL_SIGNATURE;
//         ncvinCount++;
        cvin[ncvinCount].type = cert_pi_end;

        cvout[0].type = cert_po_trustAnchor;
        cvout[0].value.pointer.cert = nullptr;
        cvout[1].type = cert_po_errorLog;
        cvout[1].value.pointer.log = &log;
        cvout[2].type = cert_po_end;

        // We check SSL server certificates, CA certificates and signing certificates.
        //
        // ToDo check keyusage, looking at CERT_KeyUsageAndTypeForCertUsage (
        // mozilla/security/nss/lib/certdb/certdb.c indicates that
        // certificateUsageSSLClient, certificateUsageSSLServer and certificateUsageSSLCA
        // are sufficient. They cover the key usages for digital signature, key agreement
        // and encipherment and certificate signature

        //never use the following usages because they are not checked properly
        // certificateUsageUserCertImport
        // certificateUsageVerifyCA
        // certificateUsageAnyCA
        // certificateUsageProtectedObjectSigner

        UsageDescription arUsages[5];
        arUsages[0] = UsageDescription( certificateUsageSSLClient, "certificateUsageSSLClient"  );
        arUsages[1] = UsageDescription( certificateUsageSSLServer, "certificateUsageSSLServer"  );
        arUsages[2] = UsageDescription( certificateUsageSSLCA, "certificateUsageSSLCA"  );
        arUsages[3] = UsageDescription( certificateUsageEmailSigner, "certificateUsageEmailSigner" );
        arUsages[4] = UsageDescription( certificateUsageEmailRecipient, "certificateUsageEmailRecipient" );

        int numUsages = SAL_N_ELEMENTS(arUsages);
        for (int i = 0; i < numUsages; i++)
        {
            SAL_INFO("xmlsecurity.xmlsec", "Testing usage " << i+1 <<
                     " of " << numUsages << ": " <<
                     arUsages[i].description <<
                     " (0x" << std::hex << static_cast<int>(arUsages[i].usage) << ")" << std::dec);

            status = CERT_PKIXVerifyCert(const_cast<CERTCertificate *>(cert), arUsages[i].usage,
                                         cvin, cvout, nullptr);
            if( status == SECSuccess )
            {
                SAL_INFO("xmlsecurity.xmlsec", "CERT_PKIXVerifyCert returned SECSuccess.");
                //When an intermediate or root certificate is checked then we expect the usage
                //certificateUsageSSLCA. This, however, will be only set when in the trust settings dialog
                //the button "This certificate can identify websites" is checked. If for example only
                //"This certificate can identify mail users" is set then the end certificate can
                //be validated and the returned usage will contain certificateUsageEmailRecipient.
                //But checking directly the root or intermediate certificate will fail. In the
                //certificate path view the end certificate will be shown as valid but the others
                //will be displayed as invalid.

                validity = csss::CertificateValidity::VALID;
                SAL_INFO("xmlsecurity.xmlsec", "Certificate is valid.");
                CERTCertificate * issuerCert = cvout[0].value.pointer.cert;
                if (issuerCert)
                {
                    SAL_INFO("xmlsecurity.xmlsec", "Root certificate: " << issuerCert->subjectName);
                    CERT_DestroyCertificate(issuerCert);
                };

                break;
            }
            else
            {
                PRIntn err = PR_GetError();
                SAL_INFO("xmlsecurity.xmlsec", "Error: " <<  err << ": " << getCertError(err));

                /* Display validation results */
                if ( log.count > 0)
                {
                    CERTVerifyLogNode *node = nullptr;
                    printChainFailure(&log);

                    for (node = log.head; node; node = node->next) {
                        if (node->cert)
                            CERT_DestroyCertificate(node->cert);
                    }
                    log.head = log.tail = nullptr;
                    log.count = 0;
                }
                SAL_INFO("xmlsecurity.xmlsec", "Certificate is invalid.");
            }
        }

    }
    else
    {
        validity = css::security::CertificateValidity::INVALID ;
    }

    //Destroying the temporary certificates
    for (auto& tmpCert : vecTmpNSSCertificates)
    {
        SAL_INFO("xmlsecurity.xmlsec", "Destroying temporary certificate");
        CERT_DestroyCertificate(tmpCert);
    }
    return validity ;
}

sal_Int32 SecurityEnvironment_NssImpl::getCertificateCharacters(
    const css::uno::Reference< css::security::XCertificate >& aCert ) {
    sal_Int32 characters ;
    const X509Certificate_NssImpl* xcert ;
    const CERTCertificate* cert ;

    Reference< XUnoTunnel > xCertTunnel( aCert, UNO_QUERY_THROW ) ;
    xcert = reinterpret_cast<X509Certificate_NssImpl*>(
        sal::static_int_cast<sal_uIntPtr>(xCertTunnel->getSomething( X509Certificate_NssImpl::getUnoTunnelId() ))) ;
    if( xcert == nullptr ) {
        throw RuntimeException() ;
    }

    cert = xcert->getNssCert() ;

    characters = 0x00000000 ;

    //Firstly, find out whether or not the cert is self-signed.
    if( SECITEM_CompareItem( &(cert->derIssuer), &(cert->derSubject) ) == SECEqual ) {
        characters |= css::security::CertificateCharacters::SELF_SIGNED ;
    } else {
        characters &= ~ css::security::CertificateCharacters::SELF_SIGNED ;
    }

    //Secondly, find out whether or not the cert has a private key.

    /*
     * i40394
     *
     * mmi : need to check whether the cert's slot is valid first
     */
    SECKEYPrivateKey* priKey = nullptr;

    if (cert->slot != nullptr)
    {
        priKey = PK11_FindPrivateKeyFromCert( cert->slot, const_cast<CERTCertificate*>(cert), nullptr ) ;
    }
    if(priKey == nullptr)
    {
        for (auto& slot : m_Slots)
        {
            priKey = PK11_FindPrivateKeyFromCert(slot, const_cast<CERTCertificate*>(cert), nullptr);
            if (priKey)
                break;
        }
    }
    if( priKey != nullptr ) {
        characters |=  css::security::CertificateCharacters::HAS_PRIVATE_KEY ;

        SECKEY_DestroyPrivateKey( priKey ) ;
    } else {
        characters &= ~ css::security::CertificateCharacters::HAS_PRIVATE_KEY ;
    }

    return characters ;
}

X509Certificate_NssImpl* NssCertToXCert( CERTCertificate* cert )
{
    X509Certificate_NssImpl* xcert ;

    if( cert != nullptr ) {
        xcert = new X509Certificate_NssImpl() ;
        if( xcert == nullptr ) {
            xcert = nullptr ;
        } else {
            xcert->setCert( cert ) ;
        }
    } else {
        xcert = nullptr ;
    }

    return xcert ;
}

X509Certificate_NssImpl* NssPrivKeyToXCert( SECKEYPrivateKey* priKey )
{
    X509Certificate_NssImpl* xcert ;

    if( priKey != nullptr ) {
        CERTCertificate* cert = PK11_GetCertFromPrivateKey( priKey ) ;

        if( cert != nullptr ) {
            xcert = NssCertToXCert( cert ) ;
        } else {
            xcert = nullptr ;
        }

        CERT_DestroyCertificate( cert ) ;
    } else {
        xcert = nullptr ;
    }

    return xcert ;
}

xmlSecKeysMngrPtr SecurityEnvironment_NssImpl::createKeysManager() {

    /*-
     * The following lines is based on the private version of xmlSec-NSS
     * crypto engine
     */
    int cSlots = m_Slots.size();
    std::unique_ptr<PK11SlotInfo*[]> sarSlots(new PK11SlotInfo*[cSlots]);
    PK11SlotInfo**  slots = sarSlots.get();
    int count = 0;
    for (auto& slot : m_Slots)
    {
        slots[count] = slot;
        ++count;
    }

    xmlSecKeysMngrPtr pKeysMngr = xmlSecKeysMngrCreate();
    if (!pKeysMngr)
        throw RuntimeException();

    if (xmlSecNssAppDefaultKeysMngrInit(pKeysMngr) < 0)
        throw RuntimeException();

    // Adopt the private key of the signing certificate, if it has any.
    if (auto pCertificate = dynamic_cast<X509Certificate_NssImpl*>(m_xSigningCertificate.get()))
    {
        if (auto pCERTCertificate = const_cast<CERTCertificate*>(pCertificate->getNssCert()))
        {
            if (pCERTCertificate && pCERTCertificate->slot)
            {
                SECKEYPrivateKey* pPrivateKey = PK11_FindPrivateKeyFromCert(pCERTCertificate->slot, pCERTCertificate, nullptr);
                xmlSecKeyDataPtr pKeyData = xmlSecNssPKIAdoptKey(pPrivateKey, nullptr);
                xmlSecKeyPtr pKey = xmlSecKeyCreate();
                xmlSecKeySetValue(pKey, pKeyData);
                xmlSecNssAppDefaultKeysMngrAdoptKey(pKeysMngr, pKey);
            }
            else
            {
                SAL_WARN("xmlsecurity.xmlsec", "Can't get the private key from the certificate.");
            }
        }
    }

    return pKeysMngr ;
}
void SecurityEnvironment_NssImpl::destroyKeysManager(xmlSecKeysMngrPtr pKeysMngr) {
    if( pKeysMngr != nullptr ) {
        xmlSecKeysMngrDestroy( pKeysMngr ) ;
    }
}

uno::Reference<security::XCertificate> SecurityEnvironment_NssImpl::createDERCertificateWithPrivateKey(
        Sequence<sal_Int8> const & raDERCertificate, Sequence<sal_Int8> const & raPrivateKey)
{
    SECStatus nStatus = SECSuccess;

    PK11SlotInfo* pSlot = PK11_GetInternalKeySlot();
    if (!pSlot)
        return uno::Reference<security::XCertificate>();

    SECItem pDerPrivateKeyInfo;
    pDerPrivateKeyInfo.data = reinterpret_cast<unsigned char *>(const_cast<sal_Int8 *>(raPrivateKey.getConstArray()));
    pDerPrivateKeyInfo.len = raPrivateKey.getLength();

    const unsigned int keyUsage = KU_KEY_ENCIPHERMENT | KU_DATA_ENCIPHERMENT | KU_DIGITAL_SIGNATURE;
    SECKEYPrivateKey* pPrivateKey = nullptr;

    bool bPermanent = false;
    bool bSensitive = false;

    nStatus = PK11_ImportDERPrivateKeyInfoAndReturnKey(
          pSlot, &pDerPrivateKeyInfo, nullptr, nullptr, bPermanent, bSensitive,
          keyUsage, &pPrivateKey, nullptr);

    if (nStatus != SECSuccess)
        return uno::Reference<security::XCertificate>();

    if (!pPrivateKey)
        return uno::Reference<security::XCertificate>();

    X509Certificate_NssImpl* pX509Certificate = createX509CertificateFromDER(raDERCertificate);
    if (!pX509Certificate)
        return uno::Reference<security::XCertificate>();

    addCryptoSlot(pSlot);

    CERTCertificate* pCERTCertificate = const_cast<CERTCertificate*>(pX509Certificate->getNssCert());
    pCERTCertificate->slot = pSlot;

    return pX509Certificate;
}

extern "C" SAL_DLLPUBLIC_EXPORT uno::XInterface*
com_sun_star_xml_crypto_SecurityEnvironment_get_implementation(
    uno::XComponentContext* /*pCtx*/, uno::Sequence<uno::Any> const& /*rSeq*/)
{
    return cppu::acquire(new SecurityEnvironment_NssImpl);
}

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