276 lines
6.7 KiB
C
276 lines
6.7 KiB
C
/*
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* respond.c: A challenge response generator for ircd-ratbox
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*
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* Note: This is not compatible with previous versions of the CHALLENGE
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* command, as the prior version was seriously flawed in many ways.
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*
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* Copyright (C) 2001 by the past and present ircd-hybrid developers.
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* Copyright (C) 2005 Aaron Sethman <androsyn@ratbox.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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* $Id: ratbox-respond.c 21723 2006-01-19 17:57:07Z androsyn $
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <openssl/err.h>
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#include <openssl/rsa.h>
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#include <openssl/pem.h>
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#include <openssl/sha.h>
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#include <unistd.h>
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static int called_passcb = 0;
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static int pass_cb(char *buf, int size, int rwflag, void *u)
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{
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int len;
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char *tmp;
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called_passcb++;
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if(!isatty(fileno(stdin)))
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{
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if(fgets(buf, size, stdin) == NULL)
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return 0;
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tmp = strpbrk(buf, "\r\n");
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if(tmp != NULL)
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*tmp = '\0';
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return strlen(buf);
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}
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tmp = getpass("Enter passphrase for private key: ");
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len = strlen(tmp);
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if (len <= 0)
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return 0;
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if (len > size)
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len = size;
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memcpy(buf, tmp, len);
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return len;
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}
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static const char base64_table[] =
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{ 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
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'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
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'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
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'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
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'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/', '\0'
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};
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static const char base64_pad = '=';
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static const short base64_reverse_table[256] = {
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1,
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-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
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-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
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41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
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};
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unsigned char *
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base64_encode(const unsigned char *str, int length)
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{
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const unsigned char *current = str;
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unsigned char *p;
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unsigned char *result;
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if ((length + 2) < 0 || ((length + 2) / 3) >= (1 << (sizeof(int) * 8 - 2))) {
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return NULL;
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}
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result = malloc(((length + 2) / 3) * 4);
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p = result;
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while (length > 2)
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{
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*p++ = base64_table[current[0] >> 2];
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*p++ = base64_table[((current[0] & 0x03) << 4) + (current[1] >> 4)];
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*p++ = base64_table[((current[1] & 0x0f) << 2) + (current[2] >> 6)];
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*p++ = base64_table[current[2] & 0x3f];
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current += 3;
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length -= 3;
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}
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if (length != 0) {
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*p++ = base64_table[current[0] >> 2];
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if (length > 1) {
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*p++ = base64_table[((current[0] & 0x03) << 4) + (current[1] >> 4)];
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*p++ = base64_table[(current[1] & 0x0f) << 2];
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*p++ = base64_pad;
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} else {
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*p++ = base64_table[(current[0] & 0x03) << 4];
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*p++ = base64_pad;
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*p++ = base64_pad;
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}
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}
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*p = '\0';
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return result;
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}
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unsigned char *
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base64_decode(const unsigned char *str, int length, int *ret)
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{
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const unsigned char *current = str;
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int ch, i = 0, j = 0, k;
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unsigned char *result;
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result = malloc(length + 1);
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while ((ch = *current++) != '\0' && length-- > 0) {
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if (ch == base64_pad) break;
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ch = base64_reverse_table[ch];
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if (ch < 0) continue;
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switch(i % 4) {
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case 0:
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result[j] = ch << 2;
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break;
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case 1:
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result[j++] |= ch >> 4;
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result[j] = (ch & 0x0f) << 4;
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break;
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case 2:
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result[j++] |= ch >>2;
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result[j] = (ch & 0x03) << 6;
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break;
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case 3:
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result[j++] |= ch;
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break;
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}
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i++;
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}
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k = j;
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if (ch == base64_pad) {
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switch(i % 4) {
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case 1:
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free(result);
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return NULL;
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case 2:
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k++;
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case 3:
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result[k++] = 0;
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}
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}
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result[j] = '\0';
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*ret = j;
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return result;
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}
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unsigned char *
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read_challenge(FILE *f)
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{
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static unsigned char buf[16384];
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char *tmp;
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if(isatty(fileno(f)))
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{
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fprintf(stderr, "Please paste challenge text now\n");
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} else {
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if(!called_passcb)
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{
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/* throw away the unneeded password line */
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fgets((char *)buf, sizeof(buf), f);
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}
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}
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fgets((char *)buf, sizeof(buf), stdin);
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tmp = strpbrk((char *)buf, "\r\n");
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if(tmp != NULL)
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*tmp = '\0';
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// fread(buf, sizeof(buf), 1, f);
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return buf;
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}
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int
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main(int argc, char **argv)
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{
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FILE *kfile;
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RSA *rsa = NULL;
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SHA_CTX ctx;
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unsigned char *ptr;
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unsigned char *ndata, ddata[512];
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int len;
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/* respond privatefile challenge */
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if (argc < 2)
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{
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puts("Error: Usage: respond privatefile");
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return -1;
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}
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if (!(kfile = fopen(argv[1], "r")))
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{
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puts("Error: Could not open the private keyfile.");
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return -1;
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}
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OpenSSL_add_all_ciphers();
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rsa = PEM_read_RSAPrivateKey(kfile, NULL,pass_cb, NULL);
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if(!rsa)
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{
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puts("Error: Unable to read your private key, is the passphrase wrong?");
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return -1;
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}
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fclose(kfile);
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while ((ptr = read_challenge(stdin))[0] != '\0') {
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ndata = base64_decode(ptr, strlen((char *)ptr), &len);
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if (ndata == NULL)
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{
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puts("Error: Bad challenge.");
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continue;
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}
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if ((len = RSA_private_decrypt(len, (unsigned char*)ndata,
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(unsigned char*)ddata, rsa, RSA_PKCS1_OAEP_PADDING)) == -1)
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{
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puts("Error: Decryption error.");
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continue;
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}
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SHA1_Init(&ctx);
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SHA1_Update(&ctx, (unsigned char *)ddata, len);
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SHA1_Final((unsigned char *)ddata, &ctx);
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ndata = base64_encode((unsigned char *)ddata, SHA_DIGEST_LENGTH);
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if(isatty(fileno(stdin)))
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{
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fprintf(stderr, "/quote CHALLENGE +");
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}
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puts((char *)ndata);
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fflush(NULL);
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}
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return 0;
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}
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