rtcs.c

cryptlib安全工具包

/****************************************************************************
*																			*
*						 cryptlib RTCS Session Management					*
*						Copyright Peter Gutmann 1999-2003					*
*																			*
****************************************************************************/

#if defined( INC_ALL )
  #include "crypt.h"
  #include "asn1.h"
  #include "asn1_ext.h"
  #include "session.h"
#else
  #include "crypt.h"
  #include "misc/asn1.h"
  #include "misc/asn1_ext.h"
  #include "session/session.h"
#endif /* Compiler-specific includes */

#ifdef USE_RTCS

/* RTCS HTTP content types */

#define RTCS_CONTENT_TYPE_REQ		"application/rtcs-request"
#define RTCS_CONTENT_TYPE_REQ_LEN	24
#define RTCS_CONTENT_TYPE_RESP		"application/rtcs-response"
#define RTCS_CONTENT_TYPE_RESP_LEN	25

/* The action to take to process an RTCS request/response */

typedef enum {
	ACTION_NONE,				/* No processing */
	ACTION_UNWRAP,				/* Unwrap raw data */
	ACTION_CRYPT,				/* Decrypt data */
	ACTION_SIGN,				/* Sig.check data */
	ACTION_LAST					/* Last valid action type */
	} ACTION_TYPE;

/* RTCS protocol state information.  This is passed around various
   subfunctions that handle individual parts of the protocol */

typedef struct {
	/* State variable information.  The nonce is copied from the request to
	   the response to prevent replay attacks */
	BYTE nonce[ CRYPT_MAX_HASHSIZE + 8 ];
	int nonceSize;
	} RTCS_PROTOCOL_INFO;

/****************************************************************************
*																			*
*								Utility Functions							*
*																			*
****************************************************************************/

/* Check for a valid-looking RTCS request/response header */

static const CMS_CONTENT_INFO FAR_BSS oidInfoSignedData = { 0, 3 };
static const CMS_CONTENT_INFO FAR_BSS oidInfoEnvelopedData = { 0, 3 };

static const OID_INFO FAR_BSS envelopeOIDinfo[] = {
	{ OID_CRYPTLIB_RTCSREQ, ACTION_UNWRAP },
	{ OID_CRYPTLIB_RTCSRESP, ACTION_UNWRAP },
	{ OID_CRYPTLIB_RTCSRESP_EXT, ACTION_UNWRAP },
	{ OID_CMS_SIGNEDDATA, ACTION_SIGN, &oidInfoSignedData },
	{ OID_CMS_ENVELOPEDDATA, ACTION_CRYPT, &oidInfoEnvelopedData },
	{ NULL, 0 }, { NULL, 0 }
	};

static int checkRtcsHeader( const void *rtcsData, const int rtcsDataLength,
							ACTION_TYPE *actionType )
	{
	STREAM stream;
	int status;

	*actionType = ACTION_NONE;

	/* We've got a valid response, check the CMS encapsulation */
	sMemConnect( &stream, rtcsData, rtcsDataLength );
	status = readCMSheader( &stream, envelopeOIDinfo, 
							FAILSAFE_ARRAYSIZE( envelopeOIDinfo, OID_INFO ), 
							NULL, FALSE );
	sMemDisconnect( &stream );
	if( cryptStatusError( status ) )
		return( status );
	*actionType = status;
	return( CRYPT_OK );
	}

/****************************************************************************
*																			*
*							Client-side Functions							*
*																			*
****************************************************************************/

/* Send a request to an RTCS server */

static int sendClientRequest( SESSION_INFO *sessionInfoPtr )
	{
	MESSAGE_DATA msgData;
	int status;

	/* Get the encoded request data and wrap it up for sending */
	setMessageData( &msgData, sessionInfoPtr->receiveBuffer,
					sessionInfoPtr->receiveBufSize );
	status = krnlSendMessage( sessionInfoPtr->iCertRequest,
							  IMESSAGE_CRT_EXPORT, &msgData,
							  CRYPT_ICERTFORMAT_DATA );
	if( cryptStatusError( status ) )
		{
		retExt( status,
				( status, SESSION_ERRINFO, 
				  "Couldn't get RTCS request data from RTCS request "
				  "object" ) );
		}
	status = envelopeWrap( sessionInfoPtr->receiveBuffer, msgData.length,
						   sessionInfoPtr->receiveBuffer,
						   sessionInfoPtr->receiveBufSize,
						   &sessionInfoPtr->receiveBufEnd,
						   CRYPT_FORMAT_CMS, CRYPT_CONTENT_RTCSREQUEST,
						   CRYPT_UNUSED );
	if( cryptStatusError( status ) )
		{
		retExt( status,
				( status, SESSION_ERRINFO, 
				  "Couldn't CMS wrap RTCS request data" ) );
		}
	DEBUG_DUMP( "rtcs_req", sessionInfoPtr->receiveBuffer,
				sessionInfoPtr->receiveBufEnd );

	/* Send the request to the responder */
	return( writePkiDatagram( sessionInfoPtr, RTCS_CONTENT_TYPE_REQ,
							  RTCS_CONTENT_TYPE_REQ_LEN ) );
	}

/* Read the response from the RTCS server */

static int readServerResponse( SESSION_INFO *sessionInfoPtr )
	{
	CRYPT_CERTIFICATE iCmsAttributes;
	MESSAGE_CREATEOBJECT_INFO createInfo;
	MESSAGE_DATA msgData;
	ACTION_TYPE actionType;
	BYTE nonceBuffer[ CRYPT_MAX_HASHSIZE + 8 ];
	int dataLength, sigResult, status;

	/* Read the response from the responder */
	status = readPkiDatagram( sessionInfoPtr );
	if( cryptStatusError( status ) )
		return( status );
	DEBUG_DUMP( "rtcs_resp", sessionInfoPtr->receiveBuffer,
				sessionInfoPtr->receiveBufEnd );
	status = checkRtcsHeader( sessionInfoPtr->receiveBuffer,
							  sessionInfoPtr->receiveBufEnd, &actionType );
	if( cryptStatusError( status ) )
		{
		retExt( status, 
				( status, SESSION_ERRINFO, 
				  "Invalid RTCS response header" ) );
		}
	if( actionType != ACTION_SIGN )
		{
		retExt( status,
				( status, SESSION_ERRINFO, 
				  "Unexpected RTCS encapsulation type %d", actionType ) );
		}

	/* Sig.check the data using the responder's key */
	status = envelopeSigCheck( sessionInfoPtr->receiveBuffer,
							   sessionInfoPtr->receiveBufEnd,
							   sessionInfoPtr->receiveBuffer, 
							   sessionInfoPtr->receiveBufSize, &dataLength,
							   CRYPT_UNUSED, &sigResult, NULL,
							   &iCmsAttributes );
	if( cryptStatusError( status ) )
		{
		retExt( status,
				( status, SESSION_ERRINFO, 
				  "Invalid RTCS response data (CMS enveloped data)" ) );
		}

	/* Make sure that the nonce in the response matches the one in the
	   request */
	setMessageData( &msgData, nonceBuffer, CRYPT_MAX_HASHSIZE );
	status = krnlSendMessage( iCmsAttributes, IMESSAGE_GETATTRIBUTE_S,
							  &msgData, CRYPT_CERTINFO_CMS_NONCE );
	krnlSendNotifier( iCmsAttributes, IMESSAGE_DECREFCOUNT );
	if( cryptStatusOK( status ) )
		{
		MESSAGE_DATA responseMsgData;
		BYTE responseNonceBuffer[ CRYPT_MAX_HASHSIZE + 8 ];

		setMessageData( &responseMsgData, responseNonceBuffer,
						CRYPT_MAX_HASHSIZE );
		status = krnlSendMessage( sessionInfoPtr->iCertRequest,
								  IMESSAGE_GETATTRIBUTE_S, &responseMsgData,
								  CRYPT_CERTINFO_CMS_NONCE );
		if( cryptStatusOK( status ) && \
			( msgData.length < 4 || \
			  msgData.length != responseMsgData.length || \
			  memcmp( msgData.data, responseMsgData.data, msgData.length ) ) )
			status = CRYPT_ERROR_SIGNATURE;
		}
	krnlSendNotifier( sessionInfoPtr->iCertRequest, IMESSAGE_DECREFCOUNT );
	sessionInfoPtr->iCertRequest = CRYPT_ERROR;
	if( cryptStatusError( status ) )
		{
		/* The response doesn't contain a nonce or it doesn't match what
		   we sent, we can't trust it.  The best error that we can return
		   here is a signature error to indicate that the integrity check
		   failed */
		retExt( status,
				( status, SESSION_ERRINFO, 
				  ( status != CRYPT_ERROR_SIGNATURE ) ? \
				  "RTCS response doesn't contain a nonce" : \
				  "RTCS response nonce doesn't match the one in the "
				  "request" ) );
		}

	/* Everything is OK, import the response */
	setMessageCreateObjectIndirectInfo( &createInfo,
							sessionInfoPtr->receiveBuffer, dataLength,
							CRYPT_CERTTYPE_RTCS_RESPONSE );
	status = krnlSendMessage( SYSTEM_OBJECT_HANDLE,
							  IMESSAGE_DEV_CREATEOBJECT_INDIRECT,
							  &createInfo, OBJECT_TYPE_CERTIFICATE );
	if( cryptStatusError( status ) )
		{
		retExt( status, 
				( status, SESSION_ERRINFO, 
				  "Invalid RTCS response contents" ) );
		}
	sessionInfoPtr->iCertResponse = createInfo.cryptHandle;

	return( CRYPT_OK );
	}

/****************************************************************************
*																			*
*							Server-side Functions							*
*																			*
****************************************************************************/

/* Read a request from an RTCS client */

static int readClientRequest( SESSION_INFO *sessionInfoPtr,
							  RTCS_PROTOCOL_INFO *protocolInfo )
	{
	MESSAGE_CREATEOBJECT_INFO createInfo;
	MESSAGE_DATA msgData;
	ACTION_TYPE actionType;
	int dataLength, status;

	/* Read the request data from the client.  We don't write an error
	   response at this initial stage to prevent scanning/DOS attacks
	   (vir sapit qui pauca loquitur) */
	status = readPkiDatagram( sessionInfoPtr );
	if( cryptStatusError( status ) )
		return( status );
	DEBUG_DUMP( "rtcs_sreq", sessionInfoPtr->receiveBuffer,
				sessionInfoPtr->receiveBufEnd );
	status = checkRtcsHeader( sessionInfoPtr->receiveBuffer,
							  sessionInfoPtr->receiveBufEnd, &actionType );
	if( cryptStatusError( status ) )
		{