Key.c revision 6fc0178d 
1/*
2Copyright 1989, 1998  The Open Group
3
4Permission to use, copy, modify, distribute, and sell this software and its
5documentation for any purpose is hereby granted without fee, provided that
6the above copyright notice appear in all copies and that both that
7copyright notice and this permission notice appear in supporting
8documentation.
9
10The above copyright notice and this permission notice shall be included in
11all copies or substantial portions of the Software.
12
13THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
16OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
17AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
18CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
19
20Except as contained in this notice, the name of The Open Group shall not be
21used in advertising or otherwise to promote the sale, use or other dealings
22in 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
35#ifdef HAVE_LIBBSD
36#include <bsd/stdlib.h> /* for arc4random_buf() */
37#endif
38
39#ifndef HAVE_ARC4RANDOM_BUF
40static void
41getbits (long data, unsigned char *dst)
42{
43    dst[0] = (data      ) & 0xff;
44    dst[1] = (data >>  8) & 0xff;
45    dst[2] = (data >> 16) & 0xff;
46    dst[3] = (data >> 24) & 0xff;
47}
48#endif
49
50#define Time_t time_t
51
52#include <stdlib.h>
53
54#if defined(HAVE_LRAND48) && defined(HAVE_SRAND48)
55#define srandom srand48
56#define random lrand48
57#endif
58#ifdef WIN32
59#include <process.h>
60#define srandom srand
61#define random rand
62#define getpid(x) _getpid(x)
63#endif
64
65#ifndef HAVE_ARC4RANDOM_BUF
66
67static void
68insecure_getrandom_buf (unsigned char *auth, int len)
69{
70    long    lowbits, highbits;
71
72    srandom ((int)getpid() ^ time((Time_t *)0));
73    lowbits = random ();
74    highbits = random ();
75    getbits (lowbits, auth);
76    getbits (highbits, auth + 4);
77}
78
79static void
80arc4random_buf (void *auth, int len)
81{
82    int	    ret;
83
84#if HAVE_GETENTROPY
85    /* weak emulation of arc4random through the getentropy libc call */
86    ret = getentropy (auth, len);
87    if (ret == 0)
88	return;
89#endif /* HAVE_GETENTROPY */
90
91    insecure_getrandom_buf (auth, len);
92}
93
94#endif /* !defined(HAVE_ARC4RANDOM_BUF) */
95
96void
97XdmcpGenerateKey (XdmAuthKeyPtr key)
98{
99    arc4random_buf(key->data, 8);
100}
101
102int
103XdmcpCompareKeys (const XdmAuthKeyPtr a, const XdmAuthKeyPtr b)
104{
105    int	i;
106
107    for (i = 0; i < 8; i++)
108	if (a->data[i] != b->data[i])
109	    return FALSE;
110    return TRUE;
111}
112
113void
114XdmcpIncrementKey (XdmAuthKeyPtr key)
115{
116    int	i;
117
118    i = 7;
119    while (++key->data[i] == 0)
120	if (--i < 0)
121	    break;
122}
123
124void
125XdmcpDecrementKey (XdmAuthKeyPtr key)
126{
127    int	i;
128
129    i = 7;
130    while (key->data[i]-- == 0)
131	if (--i < 0)
132	    break;
133}
134