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
|
/*
* This file is part of PowerDNS or dnsdist.
* Copyright -- PowerDNS.COM B.V. and its contributors
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* In addition, for the avoidance of any doubt, permission is granted to
* link this program with OpenSSL and to (re)distribute the binaries
* produced as the result of such linking.
*
* This program 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <openssl/aes.h>
#include <openssl/opensslv.h>
#if OPENSSL_VERSION_NUMBER > 0x1010000fL && !defined LIBRESSL_VERSION_NUMBER
// Older OpenSSL does not have CRYPTO_ctr128_encrypt. Before 1.1.0 the header
// file did not have the necessary extern "C" wrapper. In 1.1.0, AES_ctr128_encrypt
// was removed.
#include <openssl/modes.h>
#endif
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <sys/types.h>
#include <unistd.h>
#include <sys/time.h>
#include <limits>
#include <stdexcept>
#include <stdint.h>
#include "dns_random.hh"
using namespace std;
static AES_KEY aes_key;
static unsigned int g_offset;
static unsigned char g_counter[16], g_stream[16];
static uint32_t g_in;
static bool g_initialized;
void dns_random_init(const char data[16])
{
g_offset = 0;
memset(&g_stream, 0, sizeof(g_stream));
if (AES_set_encrypt_key((const unsigned char*)data, 128, &aes_key) < 0) {
throw std::runtime_error("AES_set_encrypt_key failed");
}
struct timeval now;
gettimeofday(&now, 0);
static_assert(sizeof(g_counter) >= (sizeof(now.tv_usec) + sizeof(now.tv_sec)), "g_counter must be large enough to get tv_sec + tv_usec");
memcpy(g_counter, &now.tv_usec, sizeof(now.tv_usec));
memcpy(g_counter+sizeof(now.tv_usec), &now.tv_sec, sizeof(now.tv_sec));
g_in = getpid() | (getppid()<<16);
g_initialized = true;
srandom(dns_random(numeric_limits<uint32_t>::max()));
}
unsigned int dns_random(unsigned int n)
{
if(!g_initialized)
abort();
uint32_t out;
#if OPENSSL_VERSION_NUMBER > 0x1010000fL && !defined LIBRESSL_VERSION_NUMBER
CRYPTO_ctr128_encrypt((const unsigned char*)&g_in, (unsigned char*) &out, sizeof(g_in), &aes_key, g_counter, g_stream, &g_offset, (block128_f) AES_encrypt);
#else
AES_ctr128_encrypt((const unsigned char*)&g_in, (unsigned char*) &out, sizeof(g_in), &aes_key, g_counter, g_stream, &g_offset);
#endif
return out % n;
}
#if 0
int main()
{
dns_random_init("0123456789abcdef");
for(int n = 0; n < 16; n++)
cerr<<dns_random(16384)<<endl;
}
#endif
|
