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/*
* $Id: nonce.c,v 1.1.1.1 2005/06/13 16:47:32 bogdan_iancu Exp $
*
* Nonce related functions
*
* Copyright (C) 2001-2003 FhG Fokus
*
* This file is part of openser, a free SIP server.
*
* openser 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
*
* openser 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 <time.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include "../../md5global.h"
#include "../../md5.h"
#include "../../dprint.h"
#include "../../ut.h"
#include "nonce.h"
/*
* Convert an integer to its hex representation,
* destination array must be at least 8 bytes long,
* this string is NOT zero terminated
*/
static inline void integer2hex(char* _d, int _s)
{
int i;
unsigned char j;
char* s;
_s = htonl(_s);
s = (char*)&_s;
for (i = 0; i < 4; i++) {
j = (s[i] >> 4) & 0xf;
if (j <= 9) {
_d[i * 2] = (j + '0');
} else {
_d[i * 2] = (j + 'a' - 10);
}
j = s[i] & 0xf;
if (j <= 9) {
_d[i * 2 + 1] = (j + '0');
} else {
_d[i * 2 + 1] = (j + 'a' - 10);
}
}
}
/*
* Convert hex string to integer
*/
static inline int hex2integer(char* _s)
{
unsigned int i, res = 0;
for(i = 0; i < 8; i++) {
res *= 16;
if ((_s[i] >= '0') && (_s[i] <= '9')) {
res += _s[i] - '0';
} else if ((_s[i] >= 'a') && (_s[i] <= 'f')) {
res += _s[i] - 'a' + 10;
} else if ((_s[i] >= 'A') && (_s[i] <= 'F')) {
res += _s[i] - 'A' + 10;
} else return 0;
}
return res;
}
/*
* Calculate nonce value
* Nonce value consists of time in seconds since 1.1 1970 and
* secret phrase
*/
void calc_nonce(char* _nonce, int _expires, str* _secret)
{
MD5_CTX ctx;
unsigned char bin[16];
MD5Init(&ctx);
integer2hex(_nonce, _expires);
MD5Update(&ctx, _nonce, 8);
MD5Update(&ctx, _secret->s, _secret->len);
MD5Final(bin, &ctx);
string2hex(bin, 16, _nonce + 8);
_nonce[8 + 32] = '\0';
}
/*
* Get expiry time from nonce string
*/
time_t get_nonce_expires(str* _n)
{
return (time_t)hex2integer(_n->s);
}
/*
* Check, if the nonce received from client is
* correct
*/
int check_nonce(str* _nonce, str* _secret)
{
int expires;
char non[NONCE_LEN + 1];
if (_nonce->s == 0) {
return -1; /* Invalid nonce */
}
if (NONCE_LEN != _nonce->len) {
return 1; /* Lengths must be equal */
}
expires = get_nonce_expires(_nonce);
calc_nonce(non, expires, _secret);
DBG("check_nonce(): comparing [%.*s] and [%.*s]\n",
_nonce->len, ZSW(_nonce->s), NONCE_LEN, non);
if (!memcmp(non, _nonce->s, _nonce->len)) {
return 0;
}
return 2;
}
/*
* Check if a nonce is stale
*/
int is_nonce_stale(str* _n)
{
if (!_n->s) return 0;
if (get_nonce_expires(_n) < time(0)) {
return 1;
} else {
return 0;
}
}
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