/*
* IRC - Internet Relay Chat, ircd/random.c
*
* This program 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 1, or (at your option)
* any later version.
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id: random.c 657 2004-06-07 19:15:49Z r33d $
*/
#include "config.h"
#include "random.h"
#include "client.h"
#include "ircd_log.h"
#include "ircd_reply.h"
#include "send.h"
#include <string.h>
#include <sys/time.h>
#include <stdio.h>
char localkey[9] = "12345678";
/* This devious-looking construct rolls a character to the left by r bits */
#define char_roll(c, r) (((c) << (r)) | ((c) >> (8 - (r))))
/* this routine is intended to be called by the feature subsystem; it takes
* a key as found in the .conf and mashes it up for the seed for the random
* number generator.
*/
int
random_seed_set(struct Client* from, const char* const* fields, int count)
{
const char *p = 0;
int len, i, roll = 0;
if (count < 1) {
if (from) /* send an error */
return need_more_params(from, "SET");
else {
log_write(LS_CONFIG, L_ERROR, 0, "Not enough fields in F line");
return 0;
}
}
len = strlen(fields[0]);
/* logic is: go through loop at least 8 times, but use all bits of seed */
for (i = 0; i < (len < 8 ? 8 : len); i++, p++) {
if (!(i % len)) { /* if we've exceeded the string length, reset */
p = fields[0];
roll++; /* so latter part of string looks different from former */
}
/* set the appropriate location of localkey according to the following
* rules: first, roll current value by an amount depending on how many
* times we've touched this character. Then take seed value and roll
* it by an amount depending upon how many times we've touched that
* character. Finally, xor the values together.
*/
localkey[i % 8] = char_roll(localkey[i % 8], (i / 8) % 8) ^
char_roll(*p, roll % 8);
}
return 1;
}
/* this is like memcpy except it xors the areas in memory. */
static void
memxor(void *dest, void *src, int n)
{
unsigned char *d = (unsigned char *)dest;
unsigned char *s = (unsigned char *)src;
while (n--)
d[n] ^= s[n];
}
/*
* MD5 transform algorithm, taken from code written by Colin Plumb,
* and put into the public domain
*
* Kev: Taken from Ted T'so's /dev/random random.c code and modified to
* be slightly simpler. That code is released under a BSD-style copyright
* OR under the terms of the GNU Public License, which should be included
* at the top of this source file.
*
* record: Cleaned up to work with ircd. RANDOM_TOKEN is defined in
* setup.h by the make script; if people start to "guess" your cookies,
* consider recompiling your server with a different random token.
*
* Kev: Now the seed comes from the feature subsystem and is fed into a
* mash routine (random_set_seed) that depends on previous values of the
* localkey array; also, part of the output of the RNG is fed back into
* the localkey array. Finally, the time values are xor'd with the local
* key to enhance non-determinability of the data fed into the MD5 core.
*/
/* The four core functions - F1 is optimized somewhat */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))
/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
/*
* The core of the MD5 algorithm, this alters an existing MD5 hash to
* reflect the addition of 16 longwords of new data. MD5Update blocks
* the data and converts bytes into longwords for this routine.
*
* original comment left in; this used to be called MD5Transform and took
* two arguments; I've internalized those arguments, creating the character
* array "localkey," which should contain 8 bytes of data. The function also
* originally returned nothing; now it returns an unsigned long that is the
* random number. It appears to be reallyrandom, so... -Kev
*
* I don't really know what this does. I tried to figure it out and got
* a headache. If you know what's good for you, you'll leave this stuff
* for the smart people and do something else. -record
*/
unsigned int ircrandom(void)
{
unsigned int a, b, c, d;
unsigned char in[16];
struct timeval tv;
gettimeofday(&tv, 0);
memcpy((void *)in, (void *)localkey, 8);
memcpy((void *)(in + 8), (void *)localkey, 8);
memxor((void *)(in + 8), (void *)&tv.tv_sec, 4);
memxor((void *)(in + 12), (void *)&tv.tv_usec, 4);
a = 0x67452301;
b = 0xefcdab89;
c = 0x98badcfe;
d = 0x10325476;
MD5STEP(F1, a, b, c, d, (int)in[0] + 0xd76aa478, 7);
MD5STEP(F1, d, a, b, c, (int)in[1] + 0xe8c7b756, 12);
MD5STEP(F1, c, d, a, b, (int)in[2] + 0x242070db, 17);
MD5STEP(F1, b, c, d, a, (int)in[3] + 0xc1bdceee, 22);
MD5STEP(F1, a, b, c, d, (int)in[4] + 0xf57c0faf, 7);
MD5STEP(F1, d, a, b, c, (int)in[5] + 0x4787c62a, 12);
MD5STEP(F1, c, d, a, b, (int)in[6] + 0xa8304613, 17);
MD5STEP(F1, b, c, d, a, (int)in[7] + 0xfd469501, 22);
MD5STEP(F1, a, b, c, d, (int)in[8] + 0x698098d8, 7);
MD5STEP(F1, d, a, b, c, (int)in[9] + 0x8b44f7af, 12);
MD5STEP(F1, c, d, a, b, (int)in[10] + 0xffff5bb1, 17);
MD5STEP(F1, b, c, d, a, (int)in[11] + 0x895cd7be, 22);
MD5STEP(F1, a, b, c, d, (int)in[12] + 0x6b901122, 7);
MD5STEP(F1, d, a, b, c, (int)in[13] + 0xfd987193, 12);
MD5STEP(F1, c, d, a, b, (int)in[14] + 0xa679438e, 17);
MD5STEP(F1, b, c, d, a, (int)in[15] + 0x49b40821, 22);
MD5STEP(F2, a, b, c, d, (int)in[1] + 0xf61e2562, 5);
MD5STEP(F2, d, a, b, c, (int)in[6] + 0xc040b340, 9);
MD5STEP(F2, c, d, a, b, (int)in[11] + 0x265e5a51, 14);
MD5STEP(F2, b, c, d, a, (int)in[0] + 0xe9b6c7aa, 20);
MD5STEP(F2, a, b, c, d, (int)in[5] + 0xd62f105d, 5);
MD5STEP(F2, d, a, b, c, (int)in[10] + 0x02441453, 9);
MD5STEP(F2, c, d, a, b, (int)in[15] + 0xd8a1e681, 14);
MD5STEP(F2, b, c, d, a, (int)in[4] + 0xe7d3fbc8, 20);
MD5STEP(F2, a, b, c, d, (int)in[9] + 0x21e1cde6, 5);
MD5STEP(F2, d, a, b, c, (int)in[14] + 0xc33707d6, 9);
MD5STEP(F2, c, d, a, b, (int)in[3] + 0xf4d50d87, 14);
MD5STEP(F2, b, c, d, a, (int)in[8] + 0x455a14ed, 20);
MD5STEP(F2, a, b, c, d, (int)in[13] + 0xa9e3e905, 5);
MD5STEP(F2, d, a, b, c, (int)in[2] + 0xfcefa3f8, 9);
MD5STEP(F2, c, d, a, b, (int)in[7] + 0x676f02d9, 14);
MD5STEP(F2, b, c, d, a, (int)in[12] + 0x8d2a4c8a, 20);
MD5STEP(F3, a, b, c, d, (int)in[5] + 0xfffa3942, 4);
MD5STEP(F3, d, a, b, c, (int)in[8] + 0x8771f681, 11);
MD5STEP(F3, c, d, a, b, (int)in[11] + 0x6d9d6122, 16);
MD5STEP(F3, b, c, d, a, (int)in[14] + 0xfde5380c, 23);
MD5STEP(F3, a, b, c, d, (int)in[1] + 0xa4beea44, 4);
MD5STEP(F3, d, a, b, c, (int)in[4] + 0x4bdecfa9, 11);
MD5STEP(F3, c, d, a, b, (int)in[7] + 0xf6bb4b60, 16);
MD5STEP(F3, b, c, d, a, (int)in[10] + 0xbebfbc70, 23);
MD5STEP(F3, a, b, c, d, (int)in[13] + 0x289b7ec6, 4);
MD5STEP(F3, d, a, b, c, (int)in[0] + 0xeaa127fa, 11);
MD5STEP(F3, c, d, a, b, (int)in[3] + 0xd4ef3085, 16);
MD5STEP(F3, b, c, d, a, (int)in[6] + 0x04881d05, 23);
MD5STEP(F3, a, b, c, d, (int)in[9] + 0xd9d4d039, 4);
MD5STEP(F3, d, a, b, c, (int)in[12] + 0xe6db99e5, 11);
MD5STEP(F3, c, d, a, b, (int)in[15] + 0x1fa27cf8, 16);
MD5STEP(F3, b, c, d, a, (int)in[2] + 0xc4ac5665, 23);
MD5STEP(F4, a, b, c, d, (int)in[0] + 0xf4292244, 6);
MD5STEP(F4, d, a, b, c, (int)in[7] + 0x432aff97, 10);
MD5STEP(F4, c, d, a, b, (int)in[14] + 0xab9423a7, 15);
MD5STEP(F4, b, c, d, a, (int)in[5] + 0xfc93a039, 21);
MD5STEP(F4, a, b, c, d, (int)in[12] + 0x655b59c3, 6);
MD5STEP(F4, d, a, b, c, (int)in[3] + 0x8f0ccc92, 10);
MD5STEP(F4, c, d, a, b, (int)in[10] + 0xffeff47d, 15);
MD5STEP(F4, b, c, d, a, (int)in[1] + 0x85845dd1, 21);
MD5STEP(F4, a, b, c, d, (int)in[8] + 0x6fa87e4f, 6);
MD5STEP(F4, d, a, b, c, (int)in[15] + 0xfe2ce6e0, 10);
MD5STEP(F4, c, d, a, b, (int)in[6] + 0xa3014314, 15);
MD5STEP(F4, b, c, d, a, (int)in[13] + 0x4e0811a1, 21);
MD5STEP(F4, a, b, c, d, (int)in[4] + 0xf7537e82, 6);
MD5STEP(F4, d, a, b, c, (int)in[11] + 0xbd3af235, 10);
MD5STEP(F4, c, d, a, b, (int)in[2] + 0x2ad7d2bb, 15);
MD5STEP(F4, b, c, d, a, (int)in[9] + 0xeb86d391, 21);
/* This feeds part of the output of the random number generator into the
* seed to further obscure any patterns
*/
memxor((void *)localkey, (void *)&a, 4);
memxor((void *)(localkey + 4), (void *)&b, 4);
/*
* We have 4 unsigned longs generated by the above sequence; this scrambles
* them together so that if there is any pattern, it will be obscured.
*
* a and b are now part of the state of the random number generator;
* returning them is a security hazard.
*/
return (c ^ d);
}
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