text: /* $XFree86: xc/lib/Xau/k5encode.c,v 1.3 2006/01/09 14:59:00 dawes Exp $ */
  /*
  
  Copyright 1993, 1994, 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.
  
  */
  
  /*
   * functions to encode/decode Kerberos V5 principals
   * into something that can be reasonable spewed over
   * the wire
   *
   * Author: Tom Yu <tlyu@MIT.EDU>
   *
   * Still needs to be fixed up wrt signed/unsigned lengths, but we'll worry
   * about that later.
   */
  
  #include <krb5/krb5.h>
  /* 9/93: krb5.h leaks some symbols */
  #undef BITS32
  #undef xfree
  
  #include <X11/X.h>
  #include <X11/Xos.h>
  #include <X11/Xmd.h>
  #include <X11/Xfuncs.h>
  
  /*
   * XauKrb5Encode
   *
   * this function encodes the principal passed to it in a format that can
   * easily be dealt with by stuffing it into an X packet.  Encoding is as
   * follows:
   *   length count of the realm name
   *   realm
   *   component count
   *   length of component
   *   actual principal component
   *   etc....
   *
   * Note that this function allocates a hunk of memory, which must be
   * freed to avoid nasty memory leak type things.  All counts are
   * byte-swapped if needed. (except for the total length returned)
   *
   * nevermind.... stuffing the encoded packet in net byte order just to
   * always do the right thing.  Don't have to frob with alignment that way.
   */
  int
  XauKrb5Encode(princ, outbuf)
      krb5_principal princ;	/* principal to encode */
      krb5_data *outbuf;		/* output buffer */
  {
      CARD16 i, numparts, totlen = 0, plen, rlen;
      char *cp, *pdata;
  
      rlen = krb5_princ_realm(princ)->length;
      numparts = krb5_princ_size(princ);
      totlen = 2 + rlen + 2;	/* include room for realm length
  				   and component count */
      for (i = 0; i < numparts; i++)
  	totlen += krb5_princ_component(princ, i)->length + 2;
      /* add 2 bytes each time for length */
      if ((outbuf->data = (char *)malloc(totlen)) == NULL)
  	return -1;
      cp = outbuf->data;
      *cp++ = (char)((int)(0xff00 & rlen) >> 8);
      *cp++ = (char)(0x00ff & rlen);
      memcpy(cp, krb5_princ_realm(princ)->data, rlen);
      cp += rlen;
      *cp++ = (char)((int)(0xff00 & numparts) >> 8);
      *cp++ = (char)(0x00ff & numparts);
      for (i = 0; i < numparts; i++)
      {
  	plen = krb5_princ_component(princ, i)->length;
  	pdata = krb5_princ_component(princ, i)->data;
  	*cp++ = (char)((int)(0xff00 & plen) >> 8);
  	*cp++ = (char)(0x00ff & plen);
  	memcpy(cp, pdata, plen);
  	cp += plen;
      }
      outbuf->length = totlen;
      return 0;
  }
  
  /*
   * XauKrb5Decode
   *
   * This function essentially reverses what XauKrb5Encode does.
   * return value: 0 if okay, -1 if malloc fails, -2 if inbuf format bad
   */
  int
  XauKrb5Decode(inbuf, princ)
      krb5_data inbuf;
      krb5_principal *princ;
  {
      CARD16 i, numparts, plen, rlen;
      CARD8 *cp, *pdata;
      
      if (inbuf.length < 4)
      {
  	return -2;
      }
      *princ = (krb5_principal)malloc(sizeof (krb5_principal_data));
      if (*princ == NULL)
  	return -1;
      bzero(*princ, sizeof (krb5_principal_data));
      cp = (CARD8 *)inbuf.data;
      rlen = *cp++ << 8;
      rlen |= *cp++;
      if (inbuf.length < 4 + (int)rlen + 2)
      {
  	krb5_free_principal(*princ);
  	return -2;
      }
      krb5_princ_realm(*princ)->data = (char *)malloc(rlen);
      if (krb5_princ_realm(*princ)->data == NULL)
      {
  	krb5_free_principal(*princ);
  	return -1;
      }
      krb5_princ_realm(*princ)->length = rlen;
      memcpy(krb5_princ_realm(*princ)->data, cp, rlen);
      cp += rlen;
      numparts = *cp++ << 8;
      numparts |= *cp++;
      krb5_princ_name(*princ) =
  	(krb5_data *)malloc(numparts * sizeof (krb5_data));
      if (krb5_princ_name(*princ) == NULL)
      {
  	krb5_free_principal(*princ);
  	return -1;
      }
      krb5_princ_size(*princ) = 0;
      for (i = 0; i < numparts; i++)
      {
  	if (cp + 2 > (CARD8 *)inbuf.data + inbuf.length)
  	{
  	    krb5_free_principal(*princ);
  	    return -2;
  	}
  	plen = *cp++ << 8;
  	plen |= *cp++;
  	if (cp + plen > (CARD8 *)inbuf.data + inbuf.length)
  	{
  	    krb5_free_principal(*princ);
  	    return -2;
  	}
  	pdata = (CARD8 *)malloc(plen);
  	if (pdata == NULL)
  	{
  	    krb5_free_principal(*princ);
  	    return -1;
  	}
  	krb5_princ_component(*princ, i)->data = (char *)pdata;
  	krb5_princ_component(*princ, i)->length = plen;
  	memcpy(pdata, cp, plen);
  	cp += plen;
  	krb5_princ_size(*princ)++;
      }
      return 0;
  }
  