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      1 /*
      2 Copyright 1989, 1998  The Open Group
      3 
      4 Permission to use, copy, modify, distribute, and sell this software and its
      5 documentation for any purpose is hereby granted without fee, provided that
      6 the above copyright notice appear in all copies and that both that
      7 copyright notice and this permission notice appear in supporting
      8 documentation.
      9 
     10 The above copyright notice and this permission notice shall be included in
     11 all copies or substantial portions of the Software.
     12 
     13 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     14 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     15 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
     16 OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
     17 AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     18 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     19 
     20 Except as contained in this notice, the name of The Open Group shall not be
     21 used in advertising or otherwise to promote the sale, use or other dealings
     22 in this Software without prior written authorization from The Open Group.
     23  *
     24  * Author:  Keith Packard, MIT X Consortium
     25  */
     26 
     27 #ifdef HAVE_CONFIG_H
     28 #include <config.h>
     29 #endif
     30 #include <X11/Xos.h>
     31 #include <X11/X.h>
     32 #include <X11/Xmd.h>
     33 #include <X11/Xdmcp.h>
     34 #include <stdlib.h>
     35 
     36 #ifndef HAVE_ARC4RANDOM_BUF
     37 static void
     38 getbits (long data, unsigned char *dst)
     39 {
     40     dst[0] = (data      ) & 0xff;
     41     dst[1] = (data >>  8) & 0xff;
     42     dst[2] = (data >> 16) & 0xff;
     43     dst[3] = (data >> 24) & 0xff;
     44 }
     45 
     46 #define Time_t time_t
     47 
     48 #if defined(HAVE_LRAND48) && defined(HAVE_SRAND48)
     49 #define srandom srand48
     50 #define random lrand48
     51 #endif
     52 #ifdef WIN32
     53 #include <process.h>
     54 #define srandom srand
     55 #define random rand
     56 #define getpid(x) _getpid(x)
     57 #endif
     58 
     59 /* Solaris 11.3.0 - 11.4.15 only define getentropy() in <sys/random.h> */
     60 #if HAVE_GETENTROPY && HAVE_SYS_RANDOM_H
     61 # include <sys/random.h>
     62 #endif
     63 
     64 static void
     65 insecure_getrandom_buf (unsigned char *auth, int len)
     66 {
     67     long    lowbits, highbits;
     68 
     69     srandom ((int)getpid() ^ time((Time_t *)0));
     70     lowbits = random ();
     71     highbits = random ();
     72     getbits (lowbits, auth);
     73     getbits (highbits, auth + 4);
     74 }
     75 
     76 static void
     77 arc4random_buf (void *auth, int len)
     78 {
     79 #if HAVE_GETENTROPY
     80     int	    ret;
     81 
     82     /* weak emulation of arc4random through the getentropy libc call */
     83     ret = getentropy (auth, len);
     84     if (ret == 0)
     85 	return;
     86 #endif /* HAVE_GETENTROPY */
     87 
     88     insecure_getrandom_buf (auth, len);
     89 }
     90 
     91 #endif /* !defined(HAVE_ARC4RANDOM_BUF) */
     92 
     93 void
     94 XdmcpGenerateKey (XdmAuthKeyPtr key)
     95 {
     96     arc4random_buf(key->data, 8);
     97 }
     98 
     99 int
    100 XdmcpCompareKeys (const XdmAuthKeyPtr a, const XdmAuthKeyPtr b)
    101 {
    102     int	i;
    103 
    104     for (i = 0; i < 8; i++)
    105 	if (a->data[i] != b->data[i])
    106 	    return FALSE;
    107     return TRUE;
    108 }
    109 
    110 void
    111 XdmcpIncrementKey (XdmAuthKeyPtr key)
    112 {
    113     int	i;
    114 
    115     i = 7;
    116     while (++key->data[i] == 0)
    117 	if (--i < 0)
    118 	    break;
    119 }
    120 
    121 void
    122 XdmcpDecrementKey (XdmAuthKeyPtr key)
    123 {
    124     int	i;
    125 
    126     i = 7;
    127     while (key->data[i]-- == 0)
    128 	if (--i < 0)
    129 	    break;
    130 }
    131