windows-xp/Source/XPSP1/NT/termsrv/remdsk/rds/t120/mst120/tprtsec.cpp

#include "precomp.h"
DEBUG_FILEZONE(ZONE_T120_MSMCSTCP);

// #define FORCE_SSL3_NEGOTIATION

#include "tprtsec.h"

/*    Tprtsec.cpp
 *
 *    Copyright (c) 1997 by Microsoft Corporation
 *
 *    Abstract:
 *        This module maintains security for the TCP transport.
 *
 */

/* External definitions */
extern HINSTANCE            g_hDllInst;

/*
 *    The following array contains a template for the X.224 data header.
 *    The 5 of the 7 bytes that it initializes are actually sent to the
 *    wire.  Bytes 3 and 4 will be set to contain the size of the PDU.
 *    The array is only used when we encode a data PDU.
 */
extern UChar g_X224Header[];


#ifdef DEBUG
//#define TESTHACKS // DANGER! don't turn on in public build!
//#define DUMP
//#define DUMPCERTS
//#undef TRACE_OUT
//#define TRACE_OUT WARNING_OUT
#endif //DEBUG

#define    SZSECPKG    UNISP_NAME_A

#define    ISC_REQ_FLAGS (    ISC_REQ_SEQUENCE_DETECT |\
                        ISC_REQ_REPLAY_DETECT |\
                        ISC_REQ_CONFIDENTIALITY |\
                        ISC_REQ_EXTENDED_ERROR |\
                        ISC_REQ_ALLOCATE_MEMORY |\
                        ISC_REQ_STREAM)

#define    ASC_REQ_FLAGS (    ASC_REQ_SEQUENCE_DETECT |\
                        ASC_REQ_REPLAY_DETECT |\
                        ASC_REQ_CONFIDENTIALITY |\
                        ASC_REQ_EXTENDED_ERROR |\
                        ASC_REQ_ALLOCATE_MEMORY |\
                        ASC_REQ_MUTUAL_AUTH |\
                        ASC_REQ_STREAM)


#if defined(DUMP) || defined(DUMPCERTS)

#define MAX_DUMP_BYTES    512

void dumpbytes(PSTR szComment, PBYTE p, int cb)
{
    int i,j;
    char buf[80];
    char buf2[80];
    DWORD dwCheckSum = 0;
    int cbShow = min(MAX_DUMP_BYTES,cb);

    for (i=0; i<cb; i++)
        dwCheckSum += p[i];

    wsprintf(buf,"%s (%d bytes, checksum %x):",
        szComment? szComment : "unknown", cb, dwCheckSum);
    OutputDebugString(buf);
    WARNING_OUT(("%s",buf));
    OutputDebugString("\n\r");

    for (i=0; i<cbShow/16; i++)
    {
        wsprintf(buf, "%08x: ", (DWORD) &p[(i*16)] );
        for (j=0; j<16; j++)
        {
            wsprintf(buf2," %02x", (int) (unsigned char) p[(i*16)+j] );
            lstrcat ( buf, buf2 );
        }
        WARNING_OUT(("%s",buf));
        lstrcat ( buf, "\n\r");
        OutputDebugString(buf);
    }
    if ( cbShow%16 )
    {
        wsprintf(buf, "%08x: ", (DWORD) &p[(i*16)] );
        for (j=0; j<cbShow%16; j++)
        {
            wsprintf(buf2," %02x", (int) (unsigned char) p[(i*16)+j] );
            lstrcat ( buf, buf2 );
        }
        WARNING_OUT(("%s",buf));
        lstrcat(buf,"\n\r");
        OutputDebugString(buf);
    }
    if ( cbShow < cb )
    {
        OutputDebugString("...\n\r");
        WARNING_OUT(("..."));
    }
}
#endif //DUMP or DUMPCERTS


///////////////////////////////////////////////////////////////////////////
// Security Interface
///////////////////////////////////////////////////////////////////////////




SecurityInterface::SecurityInterface(void) :
                LastError(TPRTSEC_NOERROR),
                bInboundCredentialValid(FALSE),
                bOutboundCredentialValid(FALSE),
                m_pbEncodedCert(NULL),
                m_cbEncodedCert(0),
                hSecurityDll(NULL),
                pfnTable(NULL)
{
}

SecurityInterface::~SecurityInterface(VOID)
{
    if ( pfnTable && bInboundCredentialValid )
    {
        pfnTable->FreeCredentialHandle ( &hInboundCredential );
    }

    if ( pfnTable && bOutboundCredentialValid )
    {
        pfnTable->FreeCredentialHandle ( &hOutboundCredential );
    }

    if ( NULL != m_pbEncodedCert )
    {
        delete m_pbEncodedCert;
    }

    if ( NULL != hSecurityDll )
    {
        FreeLibrary( hSecurityDll );
    }
}

#ifdef DUMPCERTS
VOID DumpCertStore ( SecurityInterface * pSI, char * sz, HCERTSTORE hStore)
{
    WARNING_OUT(("************ %s *************", sz));
    PCCERT_CONTEXT pC = NULL;
    int i = 0;
    char buf[256];

    while ( pC = CertEnumCertificatesInStore(
                                    hStore, (PCERT_CONTEXT)pC ))
    {
        WARNING_OUT(("----------- Entry %d: ----------------", i));

        // Dump stuff in pC->pCertInfo
        //DWORD                       dwVersion;
        //CRYPT_INTEGER_BLOB          SerialNumber;
        //CRYPT_ALGORITHM_IDENTIFIER  SignatureAlgorithm;
        //CERT_NAME_BLOB              Issuer;
        //FILETIME                    NotBefore;
        //FILETIME                    NotAfter;
        //CERT_NAME_BLOB              Subject;
        //CERT_PUBLIC_KEY_INFO        SubjectPublicKeyInfo;
        //CRYPT_BIT_BLOB              IssuerUniqueId;
        //CRYPT_BIT_BLOB              SubjectUniqueId;
        //DWORD                       cExtension;
        //PCERT_EXTENSION             rgExtension;

        WARNING_OUT(("dwVersion: %x", pC->pCertInfo->dwVersion));

        dumpbytes("SerialNumber",
            pC->pCertInfo->SerialNumber.pbData,
            pC->pCertInfo->SerialNumber.cbData );

        WARNING_OUT(("SignatureAlgorithm (name): %s",
            pC->pCertInfo->SignatureAlgorithm.pszObjId ));

        CertNameToStr( pC->dwCertEncodingType, &pC->pCertInfo->Issuer,
            CERT_X500_NAME_STR, buf, sizeof(buf) );
        WARNING_OUT(("Issuer: %s", buf ));

        WARNING_OUT(("NotBefore: %x,%x",
            pC->pCertInfo->NotBefore.dwLowDateTime,
            pC->pCertInfo->NotBefore.dwHighDateTime ));
        WARNING_OUT(("NotAfter: %x,%x",
            pC->pCertInfo->NotAfter.dwLowDateTime,
            pC->pCertInfo->NotAfter.dwHighDateTime ));

        CertNameToStr( pC->dwCertEncodingType, &pC->pCertInfo->Subject,
            CERT_X500_NAME_STR, buf, sizeof(buf) );
        WARNING_OUT(("Subject: %s", buf ));

        WARNING_OUT(("<stuff omitted for now>"));

        dumpbytes("IssuerUniqueId",
            pC->pCertInfo->IssuerUniqueId.pbData,
            pC->pCertInfo->IssuerUniqueId.cbData );

        dumpbytes("SubjectUniqueId",
            pC->pCertInfo->SubjectUniqueId.pbData,
            pC->pCertInfo->SubjectUniqueId.cbData );

        WARNING_OUT(("cExtension: %x", pC->pCertInfo->cExtension ));
        WARNING_OUT(("<stuff omitted for now>"));

        i++;
    }
}
#endif // DUMPCERTS

TransportSecurityError SecurityInterface::InitializeCreds(
                        PCCERT_CONTEXT pCertContext )
{
    SECURITY_STATUS ss;
    SCHANNEL_CRED CredData;

    CredHandle hNewInboundCred;
    CredHandle hNewOutboundCred;

    //
    // Are we going to create new creds or just clean up?
    //

    if ( NULL != pCertContext )
    {
        ZeroMemory(&CredData, sizeof(CredData));
        CredData.dwVersion = SCHANNEL_CRED_VERSION;

        #ifdef FORCE_SSL3_NEGOTIATION
        CredData.grbitEnabledProtocols = SP_PROT_SSL3_CLIENT |
                                    SP_PROT_SSL3_SERVER;
        #endif // FORCE_SSL3_NEGOTIATION

        CredData.dwFlags = SCH_CRED_NO_SERVERNAME_CHECK |
                            SCH_CRED_NO_DEFAULT_CREDS |
                            SCH_CRED_MANUAL_CRED_VALIDATION;

        CredData.cCreds = 1;
        CredData.paCred = &pCertContext;

        // Acquire client and server credential handles

        ss = pfnTable->AcquireCredentialsHandle (
            NULL,
            SZSECPKG,
            SECPKG_CRED_INBOUND,
            NULL,
            &CredData,
            NULL,
            NULL,
            &hNewInboundCred,
            &tsExpiry );

        if ( SEC_E_OK != ss )
        {
            WARNING_OUT(("AcquireCredentialsHandle (inbound) failed %lx", ss));
            LastError = TPRTSEC_SSPIFAIL;
            goto error;
        }

        ss = pfnTable->AcquireCredentialsHandle (
            NULL,
            SZSECPKG,
            SECPKG_CRED_OUTBOUND,
            NULL,
            &CredData,
            NULL,
            NULL,
            &hNewOutboundCred,
            &tsExpiry );

        if ( SEC_E_OK != ss )
        {
            WARNING_OUT(("AcquireCredentialsHandle (outbound) failed %lx", ss));
            pfnTable->FreeCredentialHandle( &hNewInboundCred );
            LastError = TPRTSEC_SSPIFAIL;
            goto error;
        }

        // Empty the SSL cache
        if (pfn_SslEmptyCache)
        {
            pfn_SslEmptyCache();
        }

        // This member can be called even when we're already initialized, as
        // when the user chooses a different cert and we need to build new
        // credentials based on it. Clear out the old information as necessary:

        if ( NULL != m_pbEncodedCert )
        {
            delete m_pbEncodedCert;
            m_pbEncodedCert = NULL;
        }
    }

    if ( bInboundCredentialValid )
        pfnTable->FreeCredentialHandle ( &hInboundCredential );

    if ( bOutboundCredentialValid )
        pfnTable->FreeCredentialHandle ( &hOutboundCredential );

    if ( NULL != pCertContext )
    {
        hInboundCredential = hNewInboundCred;
        hOutboundCredential = hNewOutboundCred;
        bInboundCredentialValid = TRUE;
        bOutboundCredentialValid = TRUE;

        //
        // Save the cert name for later use
        //

        ASSERT( NULL == m_pbEncodedCert );
        m_pbEncodedCert = new BYTE[pCertContext->cbCertEncoded];

        if ( NULL == m_pbEncodedCert )
        {
            ERROR_OUT(("Error allocating data for encoded Cert"));
            goto error;
        }

        memcpy( m_pbEncodedCert, pCertContext->pbCertEncoded,
                                pCertContext->cbCertEncoded );

        ASSERT(pCertContext->cbCertEncoded);
        m_cbEncodedCert = pCertContext->cbCertEncoded;
    }
    else
    {
        bInboundCredentialValid = FALSE;
        bOutboundCredentialValid = FALSE;
    }

    LastError = TPRTSEC_NOERROR;

error:

    return LastError;
}

TransportSecurityError SecurityInterface::Initialize(VOID)
{
    TRACE_OUT(("Initializing security interface"));

    // Load the security provider DLL

    hSecurityDll = LoadLibrary("SCHANNEL");

    if ( !hSecurityDll )
    {
        ERROR_OUT(("Loadlib schannel.dll failed"));
        LastError = TPRTSEC_NODLL;
        goto error;
    }

    // Get the initialization entrypoint
    pfnInitSecurityInterface = (INIT_SECURITY_INTERFACE)GetProcAddress(
                                hSecurityDll,
                                SECURITY_ENTRYPOINT );

    if ( NULL == pfnInitSecurityInterface )
    {
        ERROR_OUT(("GetProcAddr %s failed", SECURITY_ENTRYPOINT));
        LastError = TPRTSEC_NOENTRYPT;
        goto error;
    }

    // Get the SSPI function table
    pfnTable = (*pfnInitSecurityInterface)();

    if ( NULL == pfnTable )
    {
        ERROR_OUT(("InitializeSecurityProvider failed"));
        LastError = TPRTSEC_SSPIFAIL;
        goto error;
    }

    pfn_SslEmptyCache = (PFN_SSL_EMPTY_CACHE)GetProcAddress(hSecurityDll, SZ_SSLEMPTYCACHE);
    if ( NULL == pfnInitSecurityInterface )
    {
        ERROR_OUT(("GetProcAddr %s failed", SZ_SSLEMPTYCACHE));
        LastError = TPRTSEC_NOENTRYPT;
        goto error;
    }

error:

    return LastError;
}

BOOL SecurityInterface::GetUserCert(PBYTE pInfo, PDWORD pcbInfo)
{
    if ( NULL == m_pbEncodedCert)
    {
        WARNING_OUT(("GetUserCert: no encoded certname"));
        return FALSE;
    }

    ASSERT(m_cbEncodedCert > 0);

    if ( NULL == pInfo )
    {
        // Caller wants to know how much to allocate
        ASSERT(pcbInfo);
        *pcbInfo = m_cbEncodedCert;
        return TRUE;
    }

    if ( *pcbInfo < m_cbEncodedCert )
    {
        ERROR_OUT(("GetUserCert: insufficient buffer (%ld) %ld required",
            *pcbInfo, m_cbEncodedCert ));
        return FALSE;
    }

    memcpy ( (PCHAR)pInfo, m_pbEncodedCert, m_cbEncodedCert );
    *pcbInfo = m_cbEncodedCert;

    return TRUE;
}

///////////////////////////////////////////////////////////////////////////
// Security Context
///////////////////////////////////////////////////////////////////////////





SecurityContext::SecurityContext(PSecurityInterface pSI, LPCSTR szHostName) :
                    scstate(SECCTX_STATE_NEW),
                    fContinueNeeded(FALSE),
                    LastError(TPRTSEC_NOERROR),
                    bContextHandleValid(FALSE)
{
    ASSERT(pSI);
    ASSERT(szHostName);

    pSecurityInterface = pSI;

    OutBuffers[0].pvBuffer = NULL;
    OutBuffers[0].cbBuffer = 0;

    if ( NULL != szHostName )
    {
        wsprintf( szTargetName, "%s:%x%x", szHostName,
            pSI->hOutboundCredential.dwUpper,
            pSI->hOutboundCredential.dwLower);
        TRACE_OUT(("SecurityContext::SecurityContext: targ %s",szTargetName));
    }
    ASSERT(pSecurityInterface);
}

SecurityContext::~SecurityContext(VOID)
{
    ASSERT(pSecurityInterface);
    if ( NULL != OutBuffers[0].pvBuffer )
    {
        ASSERT(pSecurityInterface->pfnTable);

        pSecurityInterface->pfnTable->FreeContextBuffer(OutBuffers[0].pvBuffer);
        OutBuffers[0].pvBuffer = NULL;
    }
    if ( bContextHandleValid )
    {
        pSecurityInterface->pfnTable->DeleteSecurityContext(&hContext);
    }
}


TransportSecurityError SecurityContext::InitContextAttributes(VOID)
{
    SECURITY_STATUS ss;

    ss = pSecurityInterface->pfnTable->QueryContextAttributes(&hContext,
                                     SECPKG_ATTR_STREAM_SIZES,
                                     &Sizes );
    if (ss != ERROR_SUCCESS)
    {
        ERROR_OUT(("QueryContextAttributes returned [%x]", ss));
        return LastError = TPRTSEC_SSPIFAIL;
    }
    else
    {
        ASSERT (Sizes.cbHeader + Sizes.cbTrailer <= PROTOCOL_OVERHEAD_SECURITY);
        TRACE_OUT(("QueryContextAttributes returned header=%d trailer=%d",
                        Sizes.cbHeader, Sizes.cbTrailer));
    }

    #ifdef DEBUG //////////////////////////////////////////////////////////
    SecPkgContext_KeyInfo KeyInfo;

    ss = pSecurityInterface->pfnTable->QueryContextAttributes(&hContext,
                                    SECPKG_ATTR_KEY_INFO,
                                    &KeyInfo );
    if (ss != ERROR_SUCCESS)
    {
        ERROR_OUT(("QueryContextAttributes (KEY_INFO) failed %x", ss));
    }
    else
    {
        WARNING_OUT(("KEY INFO: Sign:%s Encrypt:%s Keysize:%d",
                    KeyInfo.sSignatureAlgorithmName,
                    KeyInfo.sEncryptAlgorithmName,
                    KeyInfo.KeySize ));
        pSecurityInterface->pfnTable->FreeContextBuffer(
                    KeyInfo.sSignatureAlgorithmName );
        pSecurityInterface->pfnTable->FreeContextBuffer(
                    KeyInfo.sEncryptAlgorithmName );
    }

    #endif //DEBUG ///////////////////////////////////////////////////////

    return TPRTSEC_NOERROR;
}


TransportSecurityError SecurityContext::Initialize(PBYTE pData, DWORD cbData)
{
    SECURITY_STATUS ss;
    DWORD dwReqFlags;

    TRACE_OUT(("SecurityContext Initialize (%x,%d)", pData, cbData));

    fContinueNeeded = FALSE;

    ASSERT(pSecurityInterface);
    ASSERT(SECCTX_STATE_INIT == scstate || SECCTX_STATE_NEW == scstate);

    if ( !pSecurityInterface->bOutboundCredentialValid )
    {
        WARNING_OUT(("SecurityContext::Initialize: no outbound cred"));
        return TPRTSEC_SSPIFAIL;
    }

    if ( SECCTX_STATE_INIT == scstate)
    {
        ASSERT(NULL != pData);
        ASSERT(0 != cbData);

        if ( NULL == pData || 0 == cbData )
        {
            ERROR_OUT(("Second initialize call with no data"));
            return LastError = TPRTSEC_INVALID_PARAMETER;
        }

        // Build the input buffer descriptor

        InputBufferDescriptor.cBuffers = 2;
        InputBufferDescriptor.pBuffers = InBuffers;
        InputBufferDescriptor.ulVersion = SECBUFFER_VERSION;

        InBuffers[0].BufferType = SECBUFFER_TOKEN;
        InBuffers[0].cbBuffer = cbData;
        InBuffers[0].pvBuffer = pData;

        InBuffers[1].BufferType = SECBUFFER_EMPTY;
        InBuffers[1].cbBuffer = 0;
        InBuffers[1].pvBuffer = NULL;
    }
    else
    {
        ASSERT(NULL == pData);
        ASSERT(0 == cbData);
    }

    OutputBufferDescriptor.cBuffers = 1;
    OutputBufferDescriptor.pBuffers = OutBuffers;
    OutputBufferDescriptor.ulVersion = SECBUFFER_VERSION;

    // If there's a output buffer from a previous call, free it here
    if ( NULL != OutBuffers[0].pvBuffer )
    {
        pSecurityInterface->pfnTable->FreeContextBuffer(OutBuffers[0].pvBuffer);
    }

    dwReqFlags = ISC_REQ_FLAGS;

    while ( 1 )
    {
        OutBuffers[0].BufferType = SECBUFFER_TOKEN;
        OutBuffers[0].cbBuffer = 0;
        OutBuffers[0].pvBuffer = NULL;

        #ifdef DUMP
        if (SECCTX_STATE_INIT == scstate)
        {
            dumpbytes("input token", (unsigned char *)InBuffers[0].pvBuffer,
                                                    InBuffers[0].cbBuffer);
        }
        #endif //DUMP

        ss = pSecurityInterface->pfnTable->InitializeSecurityContext(
                &(pSecurityInterface->hOutboundCredential),
                SECCTX_STATE_INIT == scstate ?  &hContext : NULL,
                szTargetName, // TargetName
                dwReqFlags,
                0, // Reserved
                SECURITY_NATIVE_DREP,
                SECCTX_STATE_INIT == scstate ?  &InputBufferDescriptor : NULL,
                0,        // reserved
                &hContext,
                &OutputBufferDescriptor,
                &ContextAttributes,
                &Expiration );

        // Some security providers don't process all the packet data
        // in one call to SCA - readjust the input buffers with the offset
        // returned in the extra buffer and iterate as necessary

        if (( SEC_I_CONTINUE_NEEDED == ss
            && NULL == OutBuffers[0].pvBuffer )
            && SECBUFFER_EXTRA == InBuffers[1].BufferType
            && 0 != InBuffers[1].cbBuffer )
        {
            InBuffers[0].pvBuffer = (PBYTE)(InBuffers[0].pvBuffer) +
                        ( InBuffers[0].cbBuffer - InBuffers[1].cbBuffer );
            InBuffers[0].BufferType = SECBUFFER_TOKEN;
            InBuffers[0].cbBuffer = InBuffers[1].cbBuffer;

            InBuffers[1].BufferType = SECBUFFER_EMPTY;
            InBuffers[1].cbBuffer = 0;
            InBuffers[1].pvBuffer = NULL;

            continue;
        }
        break;
    }


    #ifdef DUMP
    if ( SEC_E_OK == ss || SEC_I_CONTINUE_NEEDED == ss )
    {
        dumpbytes("output token",
            (unsigned char *)OutBuffers[0].pvBuffer,
            OutBuffers[0].cbBuffer);
    }
    #endif //DUMP

#ifdef ALLOW_NON_AUTHENTICATED_CLIENTS
    if ( SEC_I_INCOMPLETE_CREDENTIALS == ss )
    {
        WARNING_OUT(("InitializeSecurityContext:SEC_I_INCOMPLETE_CREDENTIALS"));

        dwReqFlags |= ISC_REQ_USE_SUPPLIED_CREDS;

        ss = pSecurityInterface->pfnTable->InitializeSecurityContext(
                &(pSecurityInterface->hOutboundCredential),
                SECCTX_STATE_INIT == scstate ?  &hContext : NULL,
                szTargetName, // TargetName
                dwReqFlags,
                0, // Reserved
                SECURITY_NATIVE_DREP,
                SECCTX_STATE_INIT == scstate ?  &InputBufferDescriptor : NULL,
                0,        // reserved
                &hContext,
                &OutputBufferDescriptor,
                &ContextAttributes,
                &Expiration );
    }
#endif // ALLOW_NON_AUTHENTICATED_CLIENTS

    if ( SEC_E_OK != ss )
    {
        if ( SEC_I_CONTINUE_NEEDED == ss && NULL != OutBuffers[0].pvBuffer )
        {
            ASSERT(SECCTX_STATE_NEW == scstate || SECCTX_STATE_INIT == scstate);

            TRACE_OUT(("Initialize: SEC_I_CONTINUE_NEEDED"));
            scstate = SECCTX_STATE_INIT;
        }
        else
        {
            ERROR_OUT(("Initialize failed: %x in state %d",(DWORD)ss,scstate));
            return LastError = TPRTSEC_SSPIFAIL;
        }
    }
    else
    {
        //  We're almost done,
        //  find the header and trailer sizes
        //

        if ( TPRTSEC_NOERROR != InitContextAttributes() )
            return LastError;

        if ( !Verify() )
            return LastError = TPRTSEC_SSPIFAIL;

        TRACE_OUT(("INITIALIZE OK"));

        scstate = SECCTX_STATE_INIT_COMPLETE;
    }

    // If there is an output buffer, set the flag to get it sent accross
    if ( ( SEC_E_OK == ss || SEC_I_CONTINUE_NEEDED == ss ) &&
                                NULL != OutBuffers[0].pvBuffer )
    {
        fContinueNeeded = TRUE;
    }

    bContextHandleValid = TRUE;
    return LastError = TPRTSEC_NOERROR;
}


TransportSecurityError SecurityContext::Accept(PBYTE pData, DWORD cbData)
{
    SECURITY_STATUS ss;

    fContinueNeeded = FALSE;

    ASSERT(SECCTX_STATE_NEW == scstate || SECCTX_STATE_ACCEPT == scstate);

    if ( !pSecurityInterface->bInboundCredentialValid )
    {
        WARNING_OUT(("SecurityContext::Initialize: no inbound cred"));
        return TPRTSEC_SSPIFAIL;
    }

    // Check to see if the required data is present
    if ( NULL == pData || 0 == cbData )
    {
        ERROR_OUT(("Accept: no data"));
        return LastError = TPRTSEC_INVALID_PARAMETER;
    }

    // Build the input buffer descriptor

    InputBufferDescriptor.cBuffers = 2;
    InputBufferDescriptor.pBuffers = InBuffers;
    InputBufferDescriptor.ulVersion = SECBUFFER_VERSION;

    InBuffers[0].BufferType = SECBUFFER_TOKEN;
    InBuffers[0].cbBuffer = cbData;
    InBuffers[0].pvBuffer = pData;

    InBuffers[1].BufferType = SECBUFFER_EMPTY;
    InBuffers[1].cbBuffer = 0;
    InBuffers[1].pvBuffer = NULL;

    // Build the output buffer descriptor

    OutputBufferDescriptor.cBuffers = 1;
    OutputBufferDescriptor.pBuffers = OutBuffers;
    OutputBufferDescriptor.ulVersion = SECBUFFER_VERSION;

    // If there's a output buffer from a previous call, free it here
    if ( NULL != OutBuffers[0].pvBuffer )
    {
        pSecurityInterface->pfnTable->FreeContextBuffer(OutBuffers[0].pvBuffer);
    }

    while ( 1 )
    {
        OutBuffers[0].BufferType = SECBUFFER_TOKEN;
        OutBuffers[0].cbBuffer = 0;
        OutBuffers[0].pvBuffer = NULL;

        #ifdef DUMP
        dumpbytes("input token", (unsigned char *)InBuffers[0].pvBuffer,
                                        InBuffers[0].cbBuffer);
        #endif //DUMP

        ss = pSecurityInterface->pfnTable->AcceptSecurityContext(
                    &(pSecurityInterface->hInboundCredential),
                    SECCTX_STATE_NEW == scstate ?  NULL : &hContext,
                    &InputBufferDescriptor,
                    ASC_REQ_FLAGS,
                    SECURITY_NATIVE_DREP,
                    &hContext, // receives new context handle
                    &OutputBufferDescriptor, // receives output security token
                    &ContextAttributes,        // receives context attributes
                    &Expiration );            // receives expiration time

        // Some security providers don't process all the packet data
        // in one call to SCA - readjust the input buffers with the offset
        // returned in the extra buffer and iterate as necessary

        if (( SEC_I_CONTINUE_NEEDED == ss
            && NULL == OutBuffers[0].pvBuffer )
            && SECBUFFER_EXTRA == InBuffers[1].BufferType
            && 0 != InBuffers[1].cbBuffer )
        {
            InBuffers[0].pvBuffer = (PBYTE)(InBuffers[0].pvBuffer) +
                        ( InBuffers[0].cbBuffer - InBuffers[1].cbBuffer );
            InBuffers[0].BufferType = SECBUFFER_TOKEN;
            InBuffers[0].cbBuffer = InBuffers[1].cbBuffer;

            InBuffers[1].BufferType = SECBUFFER_EMPTY;
            InBuffers[1].cbBuffer = 0;
            InBuffers[1].pvBuffer = NULL;

            continue;
        }
        break;
    }

    #ifdef DUMP
    if ( SEC_E_OK == ss || SEC_I_CONTINUE_NEEDED == ss )
    {
        dumpbytes("output token",
            (unsigned char *)OutBuffers[0].pvBuffer,
            OutBuffers[0].cbBuffer);
    }
    #endif //DUMP

    if ( SEC_E_OK != ss )
    {
        if ( SEC_I_CONTINUE_NEEDED == ss )
        {
            TRACE_OUT(("Accept: SEC_I_CONTINUE_NEEDED"));

            scstate = SECCTX_STATE_ACCEPT;
        }
        else
        {
            ERROR_OUT(("AcceptSecurityContext failed: %x", (DWORD)ss));
            return LastError = TPRTSEC_SSPIFAIL;
        }
    }
    else
    {

        //  We're almost done,
        //  find the header and trailer sizes
        //

        if ( TPRTSEC_NOERROR != InitContextAttributes() )
            return LastError;

        if ( !Verify() )
            return LastError = TPRTSEC_SSPIFAIL;

        TRACE_OUT(("ACCEPT OK"));

        scstate = SECCTX_STATE_ACCEPT_COMPLETE;
    }

    // If there is an output buffer, set the flag to get it sent accross
    if ( ( SEC_E_OK == ss || SEC_I_CONTINUE_NEEDED == ss ) &&
                                NULL != OutBuffers[0].pvBuffer )
    {
        fContinueNeeded = TRUE;
    }

    bContextHandleValid = TRUE;
    return LastError = TPRTSEC_NOERROR;
}


/////////////////////////////////////////////////////////////////////////////
//
// Encrypt()
//
// Description:
//    Encrypts a packet to be sent using SSL/PCT by calling SealMessage().
//
// Parameters:
//    phContext         - security context handle returned from InitiateSecConnection
//    pBufIn1, pBufIn2  - buffers to be encrypted
//    cbBufIn1,cbBufIn2    - lengths of buffers to be encrypted
//    ppBufOut          - allocated encrypted buffer, to be freed by caller
//    pcbBufOut         - length of encrypted buffer
//
// Return:
//    TransprotSecurityError
//
TransportSecurityError SecurityContext::Encrypt(
                  LPBYTE      pBufIn1,
                  UINT        cbBufIn1,
                  LPBYTE      pBufIn2,
                  UINT        cbBufIn2,
                  LPBYTE     *ppBufOut,
                  UINT        *pcbBufOut)
{
    SECURITY_STATUS           scRet = ERROR_SUCCESS;
    SecBufferDesc             Buffer;
    SecBuffer                 Buffers[4];
    UINT                      cbBufInTotal;
    LPBYTE                      pbTemp;

    // pBufIn2 and cbBufIn2 maybe NULL and 0, respectively.
    ASSERT(pBufIn1);
    ASSERT(cbBufIn1);
    ASSERT(ppBufOut);
    ASSERT(pcbBufOut);

    ASSERT(SECCTX_STATE_INIT_COMPLETE == scstate ||
            SECCTX_STATE_ACCEPT_COMPLETE == scstate);
    if (SECCTX_STATE_INIT_COMPLETE != scstate &&
        SECCTX_STATE_ACCEPT_COMPLETE != scstate)
        return LastError = TPRTSEC_INCOMPLETE_CONTEXT;

    *pcbBufOut = 0;
    cbBufInTotal = cbBufIn1 + cbBufIn2;

    // We allocate a buffer to hold the (larger) encrypted data.
    // This must be freed by the caller!
    // christts: The buffer will now also hold the X.224 header.
    if (NULL == (*ppBufOut = (LPBYTE)LocalAlloc(0, cbBufInTotal
                                + Sizes.cbHeader + Sizes.cbTrailer +
                                sizeof(X224_DATA_PACKET))))
        return LastError = TPRTSEC_NOMEM;

    pbTemp = *ppBufOut + sizeof(X224_DATA_PACKET);

    //
    // prepare data for SecBuffer
    //
    Buffers[0].pvBuffer = pbTemp;
    Buffers[0].cbBuffer = Sizes.cbHeader;
    Buffers[0].BufferType = SECBUFFER_STREAM_HEADER;

    Buffers[1].pvBuffer = pbTemp + Sizes.cbHeader;
    // Copy the user's data
    CopyMemory(Buffers[1].pvBuffer, pBufIn1, cbBufIn1);
    if (NULL != pBufIn2) {
        CopyMemory((PVoid) ((PUChar) (Buffers[1].pvBuffer) + cbBufIn1),
                    pBufIn2, cbBufIn2);
    }
    Buffers[1].cbBuffer = cbBufInTotal;
    Buffers[1].BufferType = SECBUFFER_DATA;

    Buffers[2].pvBuffer = pbTemp + Sizes.cbHeader + cbBufInTotal;
    Buffers[2].cbBuffer = Sizes.cbTrailer;
    Buffers[2].BufferType = SECBUFFER_STREAM_TRAILER;

    Buffers[3].pvBuffer = NULL;
    Buffers[3].cbBuffer = 0;
    Buffers[3].BufferType = SECBUFFER_EMPTY;

    Buffer.cBuffers = 4;
    Buffer.pBuffers = Buffers;
    Buffer.ulVersion = SECBUFFER_VERSION;

    #ifdef DUMP
    dumpbytes("data BEFORE encryption", (PBYTE)Buffers[1].pvBuffer,
                    Buffers[1].cbBuffer);
    #endif // DUMP

    // Call the semi-documented SealMessage function (Reserved3)

    scRet = ((SEAL_MESSAGE_FN)pSecurityInterface->pfnTable->Reserved3)(
        &hContext, 0, &Buffer, 0);


    if (scRet != ERROR_SUCCESS)
    {
        //
        // Map the SSPI error.
        //
        ERROR_OUT(("SealMessage failed: %x", scRet));
        LocalFree(*ppBufOut);
        return LastError = TPRTSEC_SSPIFAIL;
    }

    // We also have to add the X.224 header.
    *pcbBufOut = cbBufInTotal + Sizes.cbHeader + Sizes.cbTrailer + sizeof(X224_DATA_PACKET);
    memcpy (*ppBufOut, g_X224Header, sizeof(X224_DATA_PACKET));
    AddRFCSize(*ppBufOut, *pcbBufOut);

    #ifdef TESTHACKS
    // Inject an error...
    if (GetAsyncKeyState(VK_CONTROL)&0x8000) {
        OutputDebugString("*** INJECTING ERROR IN OUTGOING PACKET ***\n\r");
        pbTemp[(*pcbBufOut - sizeof(X224_DATA_PACKET))/2] ^= 0x55;
    }
    #endif //TESTHACKS

    #ifdef DUMP
    dumpbytes("data AFTER encryption",  pbTemp, *pcbBufOut - sizeof(X224_DATA_PACKET));
    #endif // DUMP

    TRACE_OUT(("SealMessage returned Buffer = %p, EncryptBytes = %d, UnencryptBytes = %d", pbTemp,
                *pcbBufOut - sizeof(X224_DATA_PACKET), cbBufInTotal));

    return LastError = TPRTSEC_NOERROR;
}

/////////////////////////////////////////////////////////////////////////////
//
// Decrypt
//
// Description:
//    Decrypts a buffer received using SCHANNEL by calling UnsealMessage().
//
// Parameters:
//    pBuf      - buffer to be decrypted
//    cbBufIn       - length of buffer to be decrypted
//
TransportSecurityError SecurityContext::Decrypt( PBYTE pBuf, DWORD cbBuf)
{
    SecBufferDesc   Buffer;
    SecBuffer       Buffers[4];
    DWORD           scRet = ERROR_SUCCESS;
    SecBuffer * pDataBuffer;
    int i;

    LastError = TPRTSEC_SSPIFAIL;

    ASSERT(SECCTX_STATE_INIT_COMPLETE == scstate ||
            SECCTX_STATE_ACCEPT_COMPLETE == scstate);
    if (SECCTX_STATE_INIT_COMPLETE != scstate &&
        SECCTX_STATE_ACCEPT_COMPLETE != scstate)
        return LastError = TPRTSEC_INCOMPLETE_CONTEXT;

    ASSERT(!IsBadWritePtr(pBuf,cbBuf));

    #ifdef TESTHACKS
    // Inject an error...
    if ( GetAsyncKeyState(VK_SHIFT) & 0x8000 ) {
        OutputDebugString("*** INJECTING ERROR IN INCOMING PACKET ***\n\r");
        pBuf[cbBuf/2] ^= 0x55;
    }
    #endif //TESTHACKS

    //
    // prepare data the SecBuffer for a call to SSL/PCT decryption code.
    //
    Buffers[0].pvBuffer   = pBuf;
    Buffers[0].cbBuffer      = cbBuf;

    Buffers[0].BufferType = SECBUFFER_DATA;

    Buffers[1].pvBuffer   = NULL;
    Buffers[1].cbBuffer   = 0;
    Buffers[1].BufferType = SECBUFFER_EMPTY;
    Buffers[2].pvBuffer   = NULL;
    Buffers[2].cbBuffer   = 0;
    Buffers[2].BufferType = SECBUFFER_EMPTY;
    Buffers[3].pvBuffer   = NULL;
    Buffers[3].cbBuffer   = 0;
    Buffers[3].BufferType = SECBUFFER_EMPTY;

    Buffer.cBuffers = 4;
    Buffer.pBuffers = Buffers;
    Buffer.ulVersion = SECBUFFER_VERSION;

    // Call the semi-documented UnsealMessage function (Reserved4)

    #ifdef DUMP
    dumpbytes("data BEFORE decryption:", (PBYTE)Buffers[0].pvBuffer,
                                        Buffers[0].cbBuffer);
    #endif // DUMP

    scRet = ((UNSEAL_MESSAGE_FN)pSecurityInterface->pfnTable->Reserved4)(
        &hContext, &Buffer, 0, NULL);

    pDataBuffer = NULL;

    for( i=0; i<4; i++ )
    {
        if ( NULL == pDataBuffer && SECBUFFER_DATA == Buffers[i].BufferType )
        {
            pDataBuffer = &Buffers[i];
        }
    }

    if ( NULL == pDataBuffer )
    {
        ERROR_OUT(("Unseal: no data buffer found"));
        return LastError = TPRTSEC_SSPIFAIL;
    }

    #ifdef DUMP
    dumpbytes("data AFTER decryption:", (PBYTE)pDataBuffer->pvBuffer,
                                        pDataBuffer->cbBuffer);
    #endif // DUMP

    if (scRet != ERROR_SUCCESS)
    {
        ERROR_OUT(("UnsealMessage failed with [%x]", scRet));
        return LastError = TPRTSEC_SSPIFAIL;
    }
    return LastError = TPRTSEC_NOERROR;
}


TransportSecurityError SecurityContext::AdvanceState(PBYTE pIncomingData,
                                                    DWORD cbBuf)
{
    TRACE_OUT(("AdvanceState: state %d using data %x (%d)",
        scstate, pIncomingData, cbBuf ));

    switch ( scstate )
    {
        case SECCTX_STATE_INIT:
            if ( TPRTSEC_NOERROR != Initialize( pIncomingData, cbBuf ) )
            {
                WARNING_OUT(("AdvanceState: Initialize failed in INIT"));
                goto error;
            }
            break;

        case SECCTX_STATE_ACCEPT:
        case SECCTX_STATE_NEW:
            if ( TPRTSEC_NOERROR != Accept( pIncomingData, cbBuf ) )
            {
                WARNING_OUT(("AdvanceState: Accept failed in ACCEPT or NEW"));
                goto error;
            }
            break;

        case SECCTX_STATE_INIT_COMPLETE:
        case SECCTX_STATE_ACCEPT_COMPLETE:
        case SECCTX_STATE_ERROR:
        default:
            ERROR_OUT(("AdvanceState: called in unexpected state %d"));
            goto error;

    }
    return LastError = TPRTSEC_NOERROR;

error:

    scstate = SECCTX_STATE_ERROR;
    return LastError;
}

#define CHECKFLAGS  (CERT_STORE_REVOCATION_FLAG |\
                CERT_STORE_SIGNATURE_FLAG |\
                CERT_STORE_TIME_VALIDITY_FLAG)

BOOL SecurityContext::Verify(VOID)
{
    BOOL fRet = TRUE;
    DWORD sc;
    PCCERT_CONTEXT pCert = NULL, pIssuerCert = NULL, pCACert = NULL;
    DWORD dwFlags;
    HCERTSTORE hStore = NULL;
    HCERTSTORE hCAStore = NULL;
    CHAR * pIssuer = NULL;

    ASSERT( NULL != pSecurityInterface );

    // Get the subject cert context
    sc = pSecurityInterface->pfnTable->QueryContextAttributes(&hContext,
                                        SECPKG_ATTR_REMOTE_CERT_CONTEXT,
                                        (PVOID)&pCert );

    if ( SEC_E_OK != sc )
    {
        ERROR_OUT(("QueryContextAttributes (REMOTE_CERT_CONTEXT) failed"));
        goto error;
    }

    if ( NULL == pCert )
    {
        // The caller is not authenticated
        WARNING_OUT(("No remote cred data"));
        goto error;
    }

    // Open the root store for certificate verification
    hStore = CertOpenSystemStore(0, "Root");

    if( NULL == hStore )
    {
        ERROR_OUT(("Couldn't open root certificate store"));
        goto error;
    }

    dwFlags = CHECKFLAGS;

    // Get the issuer of this cert

    pIssuerCert = CertGetIssuerCertificateFromStore(
                        hStore,
                        pCert,
                        NULL,
                        &dwFlags );

    // If the issuer of the certificate cannot be found in the root store,
    // check the CA store iteratively until we work our way back to a root
    // certificate

    pCACert = pCert;

    while ( NULL == pIssuerCert )
    {
        PCCERT_CONTEXT pTmpCert;

        if ( NULL == hCAStore )
        {
            hCAStore = CertOpenSystemStore(0, "CA");

            if ( NULL == hCAStore )
            {
                ERROR_OUT(("Couldn't open CA certificate store"));
                goto error;
            }
        }

        dwFlags =   CERT_STORE_REVOCATION_FLAG |
                    CERT_STORE_SIGNATURE_FLAG |
                    CERT_STORE_TIME_VALIDITY_FLAG;

        pTmpCert = CertGetIssuerCertificateFromStore(
                        hCAStore,
                        pCACert,
                        NULL,
                        &dwFlags );

        if ( NULL == pTmpCert )
        {
            TRACE_OUT(("Issuer not found in CA store either"));
            break;
        }

        if ( pCACert != pCert )
            CertFreeCertificateContext(pCACert);
        pCACert = pTmpCert;

        if ((( CERT_STORE_REVOCATION_FLAG & dwFlags ) &&
             !( CERT_STORE_NO_CRL_FLAG & dwFlags )) ||
             ( CERT_STORE_SIGNATURE_FLAG & dwFlags ) ||
             ( CERT_STORE_TIME_VALIDITY_FLAG & dwFlags ))
        {
            TRACE_OUT(("Problem with issuer in CA store: %x", dwFlags));
            break;
        }

        dwFlags =   CERT_STORE_REVOCATION_FLAG |
                    CERT_STORE_SIGNATURE_FLAG |
                    CERT_STORE_TIME_VALIDITY_FLAG;

        pIssuerCert = CertGetIssuerCertificateFromStore(
                        hStore,
                        pCACert,
                        NULL,
                        &dwFlags );

    }

    if ( pCACert != pCert )
        CertFreeCertificateContext ( pCACert );

    if ( NULL == pIssuerCert )
    {
        WARNING_OUT(("Verify: Can't find issuer in store"));
    }

    // Check certificate

    if ( NULL != pIssuerCert && 0 != dwFlags )
    {
        if ( dwFlags & CERT_STORE_SIGNATURE_FLAG )
        {
            WARNING_OUT(("Verify: Signature invalid"));
        }
        if ( dwFlags & CERT_STORE_TIME_VALIDITY_FLAG )
        {
            WARNING_OUT(("Verify: Cert expired"));
        }
        if ( dwFlags & CERT_STORE_REVOCATION_FLAG )
        {
            if (!(dwFlags & CERT_STORE_NO_CRL_FLAG))
            {
                WARNING_OUT(("Verify: Cert revoked"));
            }
            else
            {
                // We have no CRL for this issuer, do not
                // treat as revoked by default:
                dwFlags &= ~CERT_STORE_REVOCATION_FLAG;
            }
        }
    }

    //
    // Check for no-incomplete-certs policy
    //

#if 0
    if (( NULL == pIssuerCert || ( 0 != ( CHECKFLAGS & dwFlags )))
    {
        WARNING_OUT(("Verify: policy prevents cert use"));
        fRet = FALSE;
        goto error;
    }

    //
    // Is there a mandatory issuer?
    //

    if ( lstrlen(rePol.GetString( REGVAL_POL_ISSUER )))
    {
        DWORD cbIssuer;

        //
        // Get the issuer information
        //

        cbIssuer = CertNameToStr (
                            pCert->dwCertEncodingType,
                            &pCert->pCertInfo->Issuer,
                            CERT_FORMAT_FLAGS,
                            NULL, 0);

        if ( 0 == cbIssuer )
        {
            ERROR_OUT(("GetUserInfo: no issuer string"));
            fRet = FALSE;
            goto error;
        }

        pIssuer = new CHAR[cbIssuer + 1];

        if ( NULL == pIssuer )
        {
            ERROR_OUT(("GetUserInfo: error allocating issuer name"));
        }

        if ( 0 >= CertNameToStr (
                            pCert->dwCertEncodingType,
                            &pCert->pCertInfo->Issuer,
                            CERT_FORMAT_FLAGS,
                            pIssuer, cbIssuer+1))
        {
            ERROR_OUT(("GetUserInfo: error getting issuer string"));
            fRet = FALSE;
            goto error;
        }

        if ( lstrcmp ( rePol.GetString(REGVAL_POL_ISSUER),
            pIssuer ))
        {
            WARNING_OUT(("Issuer (%s) didn't match policy (%s)",
                pIssuer, rePol.GetString(REGVAL_POL_ISSUER)));
            fRet = FALSE;
        }
    }
#endif

error:

    if ( NULL != hStore )
    {
        CertCloseStore(hStore, 0);
    }

    if ( NULL != hCAStore )
    {
        CertCloseStore(hCAStore, 0);
    }

    if ( NULL != pCert )
    {
        CertFreeCertificateContext ( pCert );
    }

    if ( NULL != pIssuerCert )
    {
        CertFreeCertificateContext ( pIssuerCert );
    }

    if ( NULL != pIssuer )
    {
        delete pIssuer;
    }

    return fRet;
}


BOOL SecurityContext::GetUserCert(PBYTE pInfo, PDWORD pcbInfo)
{
    BOOL fRet = FALSE;
    DWORD sc;
    PCCERT_CONTEXT pCert = NULL;

    ASSERT( NULL != pSecurityInterface );

    //
    // Get the certificate from the context
    //

    sc = pSecurityInterface->pfnTable->QueryContextAttributes(&hContext,
                                        SECPKG_ATTR_REMOTE_CERT_CONTEXT,
                                        (PVOID)&pCert );

    if ( SEC_E_OK != sc )
    {
        ERROR_OUT(("QueryContextAttributes failed"));
        goto cleanup;
    }

    if ( NULL == pCert )
    {
        // The caller is not authenticated
        WARNING_OUT(("No remote cred data"));
        goto cleanup;
    }


    if ( NULL != pInfo && *pcbInfo >= pCert->cbCertEncoded )
    {
        memcpy ( pInfo, pCert->pbCertEncoded, pCert->cbCertEncoded );
    }
    *pcbInfo = pCert->cbCertEncoded;

    fRet = TRUE;

cleanup:

    if ( NULL != pCert )
    {
        CertFreeCertificateContext ( pCert );
    }

    return fRet;
}