session.c

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/****************************************************************************
*																			*
*						cryptlib Session Support Routines					*
*						Copyright Peter Gutmann 1998-2005					*
*																			*
****************************************************************************/

#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#if defined( INC_ALL )
  #include "crypt.h"
  #include "session.h"
#elif defined( INC_CHILD )
  #include "../crypt.h"
  #include "session.h"
#else
  #include "crypt.h"
  #include "session/session.h"
#endif /* Compiler-specific includes */

#ifdef USE_SESSIONS

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

/* Initialise network connection information based on the contents of the
   session object */

void initSessionNetConnectInfo( const SESSION_INFO *sessionInfoPtr,
								NET_CONNECT_INFO *connectInfo )
	{
	const ATTRIBUTE_LIST *attributeListPtr;

	initNetConnectInfo( connectInfo, sessionInfoPtr->ownerHandle,
				sessionInfoPtr->readTimeout, sessionInfoPtr->connectTimeout,
				( sessionInfoPtr->transportSession != CRYPT_ERROR ) ? \
					NET_OPTION_TRANSPORTSESSION : \
				( sessionInfoPtr->networkSocket != CRYPT_ERROR ) ? \
					NET_OPTION_NETWORKSOCKET : \
				( sessionInfoPtr->flags & SESSION_USEHTTPTUNNEL ) ? \
					NET_OPTION_HOSTNAME_TUNNEL : \
					NET_OPTION_HOSTNAME );

	/* If there's an explicit server name set, connect to it if we're the 
	   client or bind to the named interface if we're the server */
	if( ( attributeListPtr = \
			findSessionAttribute( sessionInfoPtr->attributeList,
								  CRYPT_SESSINFO_SERVER_NAME ) ) != NULL )
		{
		connectInfo->name = attributeListPtr->value;
		connectInfo->nameLength = attributeListPtr->valueLength;
		}

	/* If there's an explicit port set, connect/bind to it, otherwise use the
	   default port for the protocol */
	if( ( attributeListPtr = \
			findSessionAttribute( sessionInfoPtr->attributeList,
								  CRYPT_SESSINFO_SERVER_PORT ) ) != NULL )
		connectInfo->port = attributeListPtr->intValue;
	else
		connectInfo->port = sessionInfoPtr->protocolInfo->port;

	/* Set the user-supplied transport session or socket if required */
	connectInfo->iCryptSession = sessionInfoPtr->transportSession;
	connectInfo->networkSocket = sessionInfoPtr->networkSocket;
	}

/****************************************************************************
*																			*
*							Session Activation Functions					*
*																			*
****************************************************************************/

/* Check client/server-specific required values */

static CRYPT_ATTRIBUTE_TYPE checkClientParameters( const SESSION_INFO *sessionInfoPtr )
	{
	/* Make sure that the network comms parameters are present */
	if( sessionInfoPtr->transportSession == CRYPT_ERROR && \
		sessionInfoPtr->networkSocket == CRYPT_ERROR && \
		findSessionAttribute( sessionInfoPtr->attributeList, 
							  CRYPT_SESSINFO_SERVER_NAME ) == NULL )
		return( CRYPT_SESSINFO_SERVER_NAME );

	/* Make sure that the username + password and/or user private key are 
	   present if required */
	if( ( sessionInfoPtr->clientReqAttrFlags & SESSION_NEEDS_USERID ) && \
		findSessionAttribute( sessionInfoPtr->attributeList, 
							  CRYPT_SESSINFO_USERNAME ) == NULL )
		return( CRYPT_SESSINFO_USERNAME );
	if( ( sessionInfoPtr->clientReqAttrFlags & SESSION_NEEDS_PASSWORD ) && \
		findSessionAttribute( sessionInfoPtr->attributeList, 
							  CRYPT_SESSINFO_PASSWORD ) == NULL )
		{
		/* There's no password present, see if we can use a private key as 
		   an alternative */
		if( !( sessionInfoPtr->clientReqAttrFlags & \
			   SESSION_NEEDS_KEYORPASSWORD ) || \
			sessionInfoPtr->privateKey == CRYPT_ERROR )
			return( CRYPT_SESSINFO_PASSWORD );
			}
	if( ( sessionInfoPtr->clientReqAttrFlags & SESSION_NEEDS_PRIVATEKEY ) && \
		sessionInfoPtr->privateKey == CRYPT_ERROR )
		{
		/* There's no private key present, see if we can use a password as 
		   an alternative */
		if( !( sessionInfoPtr->clientReqAttrFlags & \
			   SESSION_NEEDS_KEYORPASSWORD ) || \
			findSessionAttribute( sessionInfoPtr->attributeList, 
								  CRYPT_SESSINFO_PASSWORD ) == NULL )
			return( CRYPT_SESSINFO_PRIVATEKEY );
		}

	/* Make sure that request/response protocol data is present if required */
	if( ( sessionInfoPtr->clientReqAttrFlags & SESSION_NEEDS_REQUEST ) && \
		sessionInfoPtr->iCertRequest == CRYPT_ERROR )
		return( CRYPT_SESSINFO_REQUEST );

	return( CRYPT_ATTRIBUTE_NONE );
	}

static CRYPT_ATTRIBUTE_TYPE checkServerParameters( const SESSION_INFO *sessionInfoPtr )
	{
	/* Make sure that server key and keyset information is present if 
	   required */
	if( ( sessionInfoPtr->serverReqAttrFlags & SESSION_NEEDS_PRIVATEKEY ) && \
		sessionInfoPtr->privateKey == CRYPT_ERROR )
		{
		/* There's no private key present, see if we can use a username +
		   password as an alternative.  In the special case of password-
		   based SSL this isn't completely foolproof since the passwords are 
		   entered into a pool from which they can be deleted explicitly if 
		   the session is aborted in a non-resumable manner (but see the 
		   note in ssl_rw.c) or implicitly over time as they're displaced by 
		   other entries, however this is an extremely unlikely case and 
		   it's too tricky trying to track what is and isn't still active to 
		   handle this fully */
		if( !( sessionInfoPtr->serverReqAttrFlags & \
			   SESSION_NEEDS_KEYORPASSWORD ) || \
			findSessionAttribute( sessionInfoPtr->attributeList, 
								  CRYPT_SESSINFO_PASSWORD ) == NULL )
			return( CRYPT_SESSINFO_PRIVATEKEY );
		}
	if( ( sessionInfoPtr->serverReqAttrFlags & SESSION_NEEDS_KEYSET ) && \
		sessionInfoPtr->cryptKeyset == CRYPT_ERROR )
		return( CRYPT_SESSINFO_KEYSET );

	return( CRYPT_ATTRIBUTE_NONE );
	}

/* Activate the network connection for a session */

static int activateConnection( SESSION_INFO *sessionInfoPtr )
	{
	CRYPT_ATTRIBUTE_TYPE errorAttribute;
	int status;

	/* Make sure that everything is set up ready to go */
	errorAttribute = ( sessionInfoPtr->flags & SESSION_ISSERVER ) ? \
					 checkServerParameters( sessionInfoPtr ) : \
					 checkClientParameters( sessionInfoPtr );
	if( errorAttribute != CRYPT_ATTRIBUTE_NONE )
		{
		setErrorInfo( sessionInfoPtr, errorAttribute, 
					  CRYPT_ERRTYPE_ATTR_ABSENT );
		return( CRYPT_ERROR_NOTINITED );
		}

	/* Allocate the send and receive buffers if necessary.  The send buffer
	   isn't used for request-response session types that use the receive
	   buffer for both outgoing and incoming data, so we only allocate it if
	   it's actually required */
	if( sessionInfoPtr->sendBuffer == NULL )
		{
		assert( sessionInfoPtr->receiveBufSize >= MIN_BUFFER_SIZE && \
				( sessionInfoPtr->sendBufSize >= MIN_BUFFER_SIZE || \
				  sessionInfoPtr->sendBufSize == CRYPT_UNUSED ) );

		if( ( sessionInfoPtr->receiveBuffer = \
						clAlloc( "activateConnection", \
								 sessionInfoPtr->receiveBufSize ) ) == NULL )
			return( CRYPT_ERROR_MEMORY );
		if( sessionInfoPtr->sendBufSize != CRYPT_UNUSED )
			{
			/* When allocating the send buffer we use the size for the
			   receive buffer since the user may have overridden the default
			   buffer size */
			if( ( sessionInfoPtr->sendBuffer = \
						clAlloc( "activateConnection", \
								 sessionInfoPtr->receiveBufSize ) ) == NULL )
				{
				clFree( "activateConnection", sessionInfoPtr->receiveBuffer );
				sessionInfoPtr->receiveBuffer = NULL;
				return( CRYPT_ERROR_MEMORY );
				}
			sessionInfoPtr->sendBufSize = sessionInfoPtr->receiveBufSize;
			}
		}
	assert( ( sessionInfoPtr->flags & SESSION_ISSERVER ) || \
			findSessionAttribute( sessionInfoPtr->attributeList, 
								  CRYPT_SESSINFO_SERVER_NAME ) != NULL || \
			sessionInfoPtr->networkSocket != CRYPT_ERROR );
	assert( findSessionAttribute( sessionInfoPtr->attributeList,
								  CRYPT_SESSINFO_SERVER_PORT ) != NULL || \
			sessionInfoPtr->protocolInfo->port > 0 );
	assert( sessionInfoPtr->receiveBuffer != NULL );

	/* Set timeouts if they're not set yet */
	if( sessionInfoPtr->connectTimeout == CRYPT_ERROR )
		{
		int timeout;

		status = krnlSendMessage( sessionInfoPtr->ownerHandle,
								  IMESSAGE_GETATTRIBUTE, &timeout,
								  CRYPT_OPTION_NET_CONNECTTIMEOUT );
		sessionInfoPtr->connectTimeout = cryptStatusOK( status ) ? \
										 timeout : 30;
		}
	if( sessionInfoPtr->readTimeout == CRYPT_ERROR )
		{
		int timeout;

		status = krnlSendMessage( sessionInfoPtr->ownerHandle,
								  IMESSAGE_GETATTRIBUTE, &timeout,
								  CRYPT_OPTION_NET_READTIMEOUT );
		sessionInfoPtr->readTimeout = cryptStatusOK( status ) ? \
									  timeout : 30;
		}
	if( sessionInfoPtr->writeTimeout == CRYPT_ERROR )
		{
		int timeout;

		status = krnlSendMessage( sessionInfoPtr->ownerHandle,
								  IMESSAGE_GETATTRIBUTE, &timeout,
								  CRYPT_OPTION_NET_WRITETIMEOUT );
		sessionInfoPtr->writeTimeout = cryptStatusOK( status ) ? \
									   timeout : 30;
		}

	/* Wait for any async driver binding to complete.  We can delay this
	   until this very late stage because no networking functionality is
	   used until this point */
	if( !krnlWaitSemaphore( SEMAPHORE_DRIVERBIND ) )
		/* The kernel is shutting down, bail out */
		return( CRYPT_ERROR_PERMISSION );

	/* If this is the first time we've got here, activate the session */
	if( !( sessionInfoPtr->flags & SESSION_PARTIALOPEN ) )
		{
		status = sessionInfoPtr->connectFunction( sessionInfoPtr );
		if( cryptStatusError( status ) )
			return( status );
		}
	assert( !sIsNullStream( &sessionInfoPtr->stream ) );

	/* If it's a secure data transport session, complete the session state
	   setup.  Note that some sessions dynamically change the protocol info
	   during the handshake to accommodate parameters negotiated during the
	   handshake, so we can only access the protocol info after the handshake
	   has completed */
	if( !sessionInfoPtr->protocolInfo->isReqResp )
		{
		/* Complete the session handshake to set up the secure state */
		status = sessionInfoPtr->transactFunction( sessionInfoPtr );
		if( cryptStatusError( status ) )
			{
			/* If we need a check of a resource (for example a user name and
			   password or cert supplied by the other side) before we can 
			   complete the handshake, we remain in the handshake state so
			   the user can re-activate the session after confirming (or
			   denying) the resource */
			if( status == CRYPT_ENVELOPE_RESOURCE )
				sessionInfoPtr->flags |= SESSION_PARTIALOPEN;

			return( status );
			}

		/* Notify the kernel that the session key context is attached to the
		   session object.  Note that we increment its reference count even
		   though it's an internal object used only by the session, because
		   otherwise it'll be automatically destroyed by the kernel as a
		   zero-reference dependent object when the session object is
		   destroyed (but before the session object itself, since it's a
		   dependent object).  This automatic cleanup could cause problems 
		   for lower-level session management code that tries to work with 
		   the (apparently still-valid) handle, for example protocols that 
		   need to encrypt a close-channel message on shutdown */
		krnlSendMessage( sessionInfoPtr->objectHandle, IMESSAGE_SETDEPENDENT,
						 &sessionInfoPtr->iCryptInContext,
						 SETDEP_OPTION_INCREF );

		/* Set up the buffer management variables */
		sessionInfoPtr->receiveBufPos = sessionInfoPtr->receiveBufEnd = 0;
		sessionInfoPtr->sendBufPos = sessionInfoPtr->sendBufStartOfs;

		/* For data transport sessions, partial reads and writes (that is,
		   sending and receiving partial packets in the presence of 
		   timeouts) are permitted */
		sioctl( &sessionInfoPtr->stream, STREAM_IOCTL_PARTIALREAD, NULL, 0 );
		sioctl( &sessionInfoPtr->stream, STREAM_IOCTL_PARTIALWRITE, NULL, 0 );
		}

	/* The handshake has been completed, switch from the handshake timeout
	   to the data transfer timeout and remember that the session has been
	   successfully established */
	sioctl( &sessionInfoPtr->stream, STREAM_IOCTL_HANDSHAKECOMPLETE, NULL, 0 );
	sessionInfoPtr->flags &= ~SESSION_PARTIALOPEN;