xref: /xsrc/external/mit/libICE/dist/src/iceauth.c

/******************************************************************************


Copyright 1993, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.

Author: Ralph Mor, X Consortium
******************************************************************************/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <X11/ICE/ICElib.h>
#include "ICElibint.h"
#include <X11/ICE/ICEutil.h>

#include <time.h>

#ifdef HAVE_ARC4RANDOM_BUF
#include <stdlib.h>	/* for arc4random_buf() */
#endif

#include <unistd.h>

static int was_called_state;

#ifndef HAVE_ARC4RANDOM_BUF

static void
emulate_getrandom_buf (
	char *auth,
	int len
)
{
    long    ldata[2];
    int	    seed;
    int	    value;
    int	    i;

#ifdef ITIMER_REAL
    {
	struct timeval  now;
	X_GETTIMEOFDAY (&now);
	ldata[0] = now.tv_sec;
	ldata[1] = now.tv_usec;
    }
#else /* ITIMER_REAL */
    {
	long    time ();
	ldata[0] = time ((long *) 0);
	ldata[1] = getpid ();
    }
#endif /* ITIMER_REAL */
    seed = (ldata[0]) + (ldata[1] << 16);
    srand (seed);
    for (i = 0; i < len; i++)
    {
	value = rand ();
	auth[i] = value & 0xff;
    }
}

static void
arc4random_buf (
	char *auth,
	int len
)
{
#if HAVE_GETENTROPY
    int	    ret;

    /* weak emulation of arc4random through the entropy libc */
    ret = getentropy (auth, len);
    if (ret == 0)
	return;
#endif /* HAVE_GETENTROPY */

    emulate_getrandom_buf (auth, len);
}

#endif /* !defined(HAVE_ARC4RANDOM_BUF) */

/*
 * MIT-MAGIC-COOKIE-1 is a sample authentication method implemented by
 * the SI.  It is not part of standard ICElib.
 */


char *
IceGenerateMagicCookie (
	int len
)
{
    char    *auth;

    if ((auth = malloc (len + 1)) == NULL)
	return (NULL);

    arc4random_buf (auth, len);

    auth[len] = '\0';
    return (auth);
}



IcePoAuthStatus
_IcePoMagicCookie1Proc (
	IceConn		iceConn,
	IcePointer	*authStatePtr,
	Bool 		cleanUp,
	Bool		swap,
	int     	authDataLen,
	IcePointer	authData,
	int 		*replyDataLenRet,
	IcePointer	*replyDataRet,
	char    	**errorStringRet
)
{
    if (cleanUp)
    {
	/*
	 * We didn't allocate any state.  We're done.
	 */

	return (IcePoAuthDoneCleanup);
    }

    *errorStringRet = NULL;

    if (*authStatePtr == NULL)
    {
	/*
	 * This is the first time we're being called.  Search the
	 * authentication data for the first occurrence of
	 * MIT-MAGIC-COOKIE-1 that matches iceConn->connection_string.
	 */

	unsigned short  length;
	char		*data;

	_IceGetPoAuthData ("ICE", iceConn->connection_string,
	    "MIT-MAGIC-COOKIE-1", &length, &data);

	if (!data)
	{
	    const char *tempstr =
		"Could not find correct MIT-MAGIC-COOKIE-1 authentication";

	    *errorStringRet = strdup(tempstr);

	    return (IcePoAuthFailed);
	}
	else
	{
	    *authStatePtr = (IcePointer) &was_called_state;

	    *replyDataLenRet = length;
	    *replyDataRet = data;

	    return (IcePoAuthHaveReply);
	}
    }
    else
    {
	/*
	 * We should never get here for MIT-MAGIC-COOKIE-1 since it is
	 * a single pass authentication method.
	 */

	const char *tempstr =
	    "MIT-MAGIC-COOKIE-1 authentication internal error";

	*errorStringRet = strdup(tempstr);

	return (IcePoAuthFailed);
    }
}

IcePoAuthProc	_IcePoAuthProcs[] = {_IcePoMagicCookie1Proc};


IcePaAuthStatus
_IcePaMagicCookie1Proc (
	IceConn		iceConn,
	IcePointer	*authStatePtr,
	Bool		swap,
	int     	authDataLen,
	IcePointer	authData,
	int 		*replyDataLenRet,
	IcePointer	*replyDataRet,
	char    	**errorStringRet
)
{
    *errorStringRet = NULL;
    *replyDataLenRet = 0;
    *replyDataRet = NULL;

    if (*authStatePtr == NULL)
    {
	/*
	 * This is the first time we're being called.  We don't have
	 * any data to pass to the other client.
	 */

	*authStatePtr = (IcePointer) &was_called_state;

	return (IcePaAuthContinue);
    }
    else
    {
	/*
	 * Search the authentication data for the first occurrence of
	 * MIT-MAGIC-COOKIE-1 that matches iceConn->connection_string.
	 */

	unsigned short  length;
	char		*data;

	_IceGetPaAuthData ("ICE", iceConn->connection_string,
	    "MIT-MAGIC-COOKIE-1", &length, &data);

	if (data)
	{
	    IcePaAuthStatus stat;

	    if (authDataLen == length &&
	        memcmp (authData, data, authDataLen) == 0)
	    {
		stat = IcePaAuthAccepted;
	    }
	    else
	    {
		const char *tempstr
		    = "MIT-MAGIC-COOKIE-1 authentication rejected";

		*errorStringRet = strdup(tempstr);

		stat = IcePaAuthRejected;
	    }

	    free (data);
	    return (stat);
	}
	else
	{
	    /*
	     * We should never get here because in the ConnectionReply
	     * we should have passed all the valid methods.  So we should
	     * always find a valid entry.
	     */

	    const char *tempstr =
		"MIT-MAGIC-COOKIE-1 authentication internal error";

	    *errorStringRet = strdup(tempstr);

	    return (IcePaAuthFailed);
	}
    }
}

IcePaAuthProc	_IcePaAuthProcs[] = {_IcePaMagicCookie1Proc};