1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
|
/* random.c - random number generator
* Copyright (c) 1997 by Werner Koch (dd9jn)
*
* This file is part of G10.
*
* G10 is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* G10 is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include "util.h"
#include "cipher.h"
#include "ttyio.h"
struct cache {
int len;
byte buffer[100]; /* fixme: should be allocated with m_alloc_secure()*/
};
static struct cache cache[3];
#define MASK_LEVEL(a) do {if( a > 2 ) a = 2; else if( a < 0 ) a = 0; } while(0)
static void fill_buffer( byte *buffer, size_t length, int level );
static int quick_test;
int
quick_random_gen( int onoff )
{
int last = quick_test;
if( onoff != -1 )
quick_test = onoff;
return last;
}
/****************
* Fill the buffer with LENGTH bytes of cryptologic strong
* random bytes. level 0 is not very strong, 1 is strong enough
* for most usage, 2 is good for key generation stuff but may be very slow.
*/
void
randomize_buffer( byte *buffer, size_t length, int level )
{
for( ; length; length-- )
*buffer++ = get_random_byte(level);
}
byte
get_random_byte( int level )
{
MASK_LEVEL(level);
if( !cache[level].len ) {
fill_buffer(cache[level].buffer, DIM(cache[level].buffer), level );
cache[level].len = DIM(cache[level].buffer);
}
return cache[level].buffer[--cache[level].len];
}
#ifdef HAVE_DEV_RANDOM
static int
open_device( const char *name, int minor )
{
int fd;
struct stat sb;
fd = open( name, O_RDONLY );
if( fd == -1 )
log_fatal("can't open %s: %s\n", name, strerror(errno) );
if( fstat( fd, &sb ) )
log_fatal("stat() off %s failed: %s\n", name, strerror(errno) );
#if defined(__sparc__) && defined(__linux__)
#warning something is wrong with UltraPenguin /dev/random
#else
if( !S_ISCHR(sb.st_mode) )
log_fatal("invalid random device!\n" );
#endif
return fd;
}
static void
fill_buffer( byte *buffer, size_t length, int level )
{
static int fd_urandom = -1;
static int fd_random = -1;
int fd;
int n;
int warn=0;
if( level == 2 && !quick_test ) {
if( fd_random == -1 )
fd_random = open_device( "/dev/random", 8 );
fd = fd_random;
}
else {
if( fd_urandom == -1 )
fd_urandom = open_device( "/dev/urandom", 9 );
fd = fd_urandom;
}
do {
fd_set rfds;
struct timeval tv;
int rc;
FD_ZERO(&rfds);
FD_SET(fd, &rfds);
tv.tv_sec = 3;
tv.tv_usec = 0;
if( !(rc=select(fd+1, &rfds, NULL, NULL, &tv)) ) {
if( !warn )
tty_printf(
"\nNot enough random bytes available. Please do some other work to give
the OS a chance to collect more entropy! (Need %d more bytes)\n", length );
warn = 1;
continue;
}
else if( rc == -1 ) {
tty_printf("select() error: %s\n", strerror(errno));
continue;
}
assert( length < 200 );
do {
n = read(fd, buffer, length );
if( n > length ) {
log_error("bogus read from random device (n=%d)\n", n );
n = length;
}
} while( n == -1 && errno == EINTR );
if( n == -1 )
log_fatal("read error on random device: %s\n", strerror(errno) );
assert( n <= length );
buffer += n;
length -= n;
} while( length );
}
#else /* not HAVE_DEV_RANDOM */
#ifndef RAND_MAX /* for SunOS */
#define RAND_MAX 32767
#endif
static void
fill_buffer( byte *buffer, size_t length, int level )
{
static int initialized=0;
if( !initialized ) {
log_info("warning: using insecure random number generator!!\n");
tty_printf("The random number generator is only a kludge to let\n"
"it compile - it is in no way a strong RNG!\n\n"
"DON'T USE ANY DATA GENERATED BY THIS PROGRAM!!\n\n");
initialized=1;
#ifdef HAVE_RAND
srand(make_timestamp()*getpid());
#else
srandom(make_timestamp()*getpid());
#endif
}
#ifdef HAVE_RAND
while( length-- )
*buffer++ = ((unsigned)(1 + (int) (256.0*rand()/(RAND_MAX+1.0)))-1);
#else
while( length-- )
*buffer++ = ((unsigned)(1 + (int) (256.0*random()/(RAND_MAX+1.0)))-1);
#endif
}
#endif
|
