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/*
* Copyright (c) 2001-2014 ircd-hybrid development team
*
* 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 2 of the License, 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
* USA
*/
/*! \file respond.c
* \brief A simple RSA authentification challenge response generator for the ircd-hybrid CHALLENGE command.
* \version $Id$
*/
#include <stdio.h>
#include <string.h>
#include <openssl/err.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/md5.h>
#include <unistd.h>
static int insecure_mode = 0;
static char *pass_param = NULL;
static int
pass_cb(char *buf, int size, int rwflag, void *u)
{
int len = 0;
char *tmp = NULL;
if (insecure_mode != 0)
{
if (pass_param == NULL)
return 0;
len = strlen(pass_param);
if (len <= 0) /* This SHOULDN'T happen */
return 0;
if (len > size)
len = size;
memcpy(buf, pass_param, len);
return len;
}
tmp = getpass("Enter passphrase for challenge: ");
if (!tmp)
{
puts("Couldn't read passphrase from stdin!");
exit(-1);
}
len = strlen(tmp);
if (len <= 0)
return 0;
if (len > size)
len = size;
memcpy(buf, tmp, len);
return len;
}
static void
binary_to_hex(unsigned char *bin, char *hex, int length)
{
static const char trans[] = "0123456789ABCDEF";
int i;
for (i = 0; i < length; ++i)
{
hex[(i << 1) ] = trans[bin[i] >> 4];
hex[(i << 1) + 1] = trans[bin[i] & 0xf];
}
hex[i << 1] = '\0';
}
static int
hex_to_binary(const char *from, char *to, int len)
{
char a, b = 1;
int p = 0;
const char *ptr = from;
while (-1)
{
a = *ptr++;
if (!a)
break;
b = *ptr++;
/* If this happens, we got bad input. */
if (!b)
break;
if (p >= len)
break;
if (!((a >= '0' && a <= '9') || (a >= 'A' && a <= 'F')))
break;
if (!((b >= '0' && b <= '9') || (b >= 'A' && b <= 'F')))
break;
to[p++] = ((a <= '9') ? (a - '0') : (a - 'A' + 0xA)) << 4 |
((b <= '9') ? (b - '0') : (b - 'A' + 0xA));
}
return p;
}
int
main(int argc, char **argv)
{
FILE *kfile = NULL;
RSA *rsa = NULL;
char ndata[257], ddata[257];
/* respond privatefile challenge */
if (argc < 3)
{
puts("Usage: respond privatefile challenge [passphrase]");
return 0;
}
if (argc == 4)
{
/*
* This is TOTALLY insecure and not recommended, but for
* interfacing with irc client scripts, it's either this
* or don't use a passphrase.
*
* The likelihood of a passphrase leaking isn't TOO great,
* only ps auxww will show it, and even then, only at the
* precise moment this is called.
*/
insecure_mode = 1;
pass_param = argv[3];
}
if (!(kfile = fopen(argv[1], "r")))
{
puts("Could not open the private keyfile.");
return 0;
}
SSLeay_add_all_ciphers();
rsa = PEM_read_RSAPrivateKey(kfile, NULL,pass_cb, NULL);
if (!rsa)
{
puts("Unable to read your private key, is the passphrase wrong?");
return 0;
}
fclose(kfile);
if (hex_to_binary(argv[2], ndata, 128) != 128)
{
puts("Bad challenge.");
return -1;
}
if (RSA_private_decrypt(128, (unsigned char *)ndata,
(unsigned char *)ddata, rsa, RSA_PKCS1_PADDING) == -1)
{
puts("Decryption error.");
return -1;
}
binary_to_hex((unsigned char *)ddata, ndata, 32);
puts(ndata);
return 0;
}
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