Unwrap.c   [plain text]

/*
 * $Xorg: Unwrap.c,v 1.4 2001/02/09 02:03:48 xorgcvs Exp $
 *
 * 
Copyright 1989, 1998  The Open Group

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 * *
 * Author:  Keith Packard, MIT X Consortium
 */

/* $XFree86: xc/lib/Xdmcp/Unwrap.c,v 1.3 2001/01/17 19:42:44 dawes Exp $ */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <X11/Xos.h>
#include <X11/X.h>
#include <X11/Xmd.h>
#include <X11/Xdmcp.h>

#ifdef HASXDMAUTH

/*
 * The following function exists only to demonstrate the
 * desired functional interface for this routine.  You will
 * need to add the appropriate algorithm if you wish to
 * use XDM-AUTHENTICATION-1/XDM-AUTHORIZATION-1.
 *
 * The interface for this routine is quite simple.  All three
 * arguments are arrays of 8 unsigned characters, the first two
 * are 64 bits of useful data, the last is 56 bits of useful
 * data packed into 8 bytes, using the low 7 bits of each
 * byte, filling the high bit with odd parity.
 *
 * Examine the XDMCP specification for the correct algorithm
 */

#include "Wrap.h"

void
XdmcpUnwrap (
    unsigned char	*input,
    unsigned char	*wrapper,
    unsigned char	*output,
    int			bytes)
{
    int			i, j, k;
    unsigned char	tmp[8];
    unsigned char	blocks[2][8];
    unsigned char	expand_wrapper[8];
    auth_wrapper_schedule	schedule;

    _XdmcpWrapperToOddParity (wrapper, expand_wrapper);
    _XdmcpAuthSetup (expand_wrapper, schedule);

    k = 0;
    for (j = 0; j < bytes; j += 8)
    {
	if (bytes - j < 8)
	    return; /* bad input length */
	for (i = 0; i < 8; i++)
	    blocks[k][i] = input[j + i];
	_XdmcpAuthDoIt ((unsigned char *) (input + j), (unsigned char *) tmp, schedule, 0);
	/* block chaining */
	k = (k == 0) ? 1 : 0;
	for (i = 0; i < 8; i++)
	{
	    if (j == 0)
		output[j + i] = tmp[i];
	    else
		output[j + i] = tmp[i] ^ blocks[k][i];
	}
    }
}

#endif /* HASXDMAUTH */