client.c

   1 /*
   2  * Copyright (C) 1997-2006 Andre Noll <maan@systemlinux.org>
   3  *
   4  *     This program is free software; you can redistribute it and/or modify
   5  *     it under the terms of the GNU General Public License as published by
   6  *     the Free Software Foundation; either version 2 of the License, or
   7  *     (at your option) any later version.
   8  *
   9  *     This program is distributed in the hope that it will be useful,
  10  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *     GNU General Public License for more details.
  13  *
  14  *     You should have received a copy of the GNU General Public License
  15  *     along with this program; if not, write to the Free Software
  16  *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  17  */
  18
  19 /** \file client.c the client program used to connect to para_server */
  20
  21 #include "para.h"
  22 #include "config.h"
  23 #include "client.cmdline.h"
  24 #include "crypt.h"
  25 #include "rc4.h"
  26 #include <openssl/rc4.h>
  27 #include "net.h"
  28 #include "string.h"
  29
  30 struct gengetopt_args_info args_info;
  31
  32 /*
  33  * client log function
  34  */
  35 void para_log(int ll, const char* fmt,...)
  36 {
  37         va_list argp;
  38         FILE *outfd;
  39
  40         /* ignore log message if loglevel is not high enough */
  41         if (ll < args_info.loglevel_arg)
  42                 return;
  43         va_start(argp, fmt);
  44         vfprintf(stderr, fmt, argp);
  45         va_end(argp);
  46 }
  47
  48 void get_options(int argc, char *argv[],
  49         char **config_file, char **key_file)
  50 {
  51         char *home;
  52         static char default_key_file[_POSIX_PATH_MAX] = "";
  53         static char default_config_file[_POSIX_PATH_MAX] = "";
  54         struct stat statbuf;
  55         int ret;
  56
  57         cmdline_parser(argc, argv, &args_info);
  58         if (!args_info.user_given)
  59                 args_info.user_arg = para_logname();
  60         if (!args_info.key_file_given) {
  61                 home = para_homedir();
  62                 sprintf(default_key_file, "%s/.paraslash/key.%s", home,
  63                         args_info.user_arg);
  64                 free(home);
  65         }
  66         if (!args_info.config_file_given) {
  67                 home = para_homedir();
  68                 sprintf(default_config_file, "%s/.paraslash/client.conf",
  69                         home);
  70                 free(home);
  71         }
  72         if (!args_info.config_file_given)
  73                 *config_file = default_config_file;
  74         else
  75                 *config_file = args_info.config_file_arg;
  76         ret = stat(*config_file, &statbuf);
  77         if (ret && args_info.config_file_given) {
  78                 fprintf(stderr, "can not stat config file %s\n",
  79                         args_info.config_file_arg);
  80                 exit(EXIT_FAILURE);
  81         }
  82         if (!ret)
  83                 cmdline_parser_configfile(*config_file, &args_info, 0, 0, 0);
  84         if (!args_info.key_file_given)
  85                 *key_file = default_key_file;
  86         else
  87                 *key_file = args_info.key_file_arg;
  88 }
  89
  90 static RC4_KEY rc4_recv_key;
  91 static RC4_KEY rc4_send_key;
  92 static unsigned char rc4_buf[2 * RC4_KEY_LEN];
  93
  94 static void rc4_send(unsigned long len, const unsigned char *indata, unsigned char *outdata)
  95 {
  96         RC4(&rc4_send_key, len, indata, outdata);
  97 }
  98
  99 static void rc4_recv(unsigned long len, const unsigned char *indata, unsigned char *outdata)
 100 {
 101         RC4(&rc4_recv_key, len, indata, outdata);
 102 }
 103 void (*crypt_function_recv)(unsigned long len, const unsigned char *indata, unsigned char *outdata);
 104 void (*crypt_function_send)(unsigned long len, const unsigned char *indata, unsigned char *outdata);
 105
 106
 107 static void append_str(char **data, const char* append)
 108 {
 109         if (*data) {
 110                 char *tmp = make_message("%s\n%s", *data, append);
 111                 free(*data);
 112                 *data = tmp;
 113         } else
 114                 *data = para_strdup(append);
 115 }
 116
 117 /*
 118  * MAIN
 119  */
 120 int main(int argc, char *argv[])
 121 {
 122
 123         int sockfd, numbytes, i, received, ret;
 124         struct hostent *he;
 125         struct sockaddr_in their_addr;
 126         char *command = NULL;
 127         char buf[8192];
 128         char *auth_str;
 129         char *key_file, *config_file;
 130         long unsigned challenge_nr;
 131
 132         get_options(argc, argv, &config_file, &key_file);
 133         if (args_info.loglevel_arg <= NOTICE)
 134                 cmdline_parser_print_version();
 135         PARA_INFO_LOG(
 136                 "current loglevel: %d\n"
 137                 "using config_file: %s\n"
 138                 "using key_file: %s\n"
 139                 "connecting to %s:%d\n",
 140                 args_info.loglevel_arg,
 141                 config_file,
 142                 key_file,
 143                 args_info.hostname_arg,
 144                 args_info.server_port_arg
 145         );
 146         if (!args_info.inputs_num) {
 147                 PARA_ERROR_LOG("%s", "syntax error\n");
 148                 exit(EXIT_FAILURE);
 149         }
 150         /* concat args */
 151         for (i = 0; i < args_info.inputs_num; i++)
 152                 append_str(&command, args_info.inputs[i]);
 153
 154         crypt_function_recv = NULL;
 155         crypt_function_send = NULL;
 156         /* get the host info */
 157         PARA_NOTICE_LOG("getting host info of %s\n",
 158                 args_info.hostname_arg);
 159         if (!(he = get_host_info(args_info.hostname_arg)))
 160                 exit(EXIT_FAILURE);
 161         /* get new socket */
 162         if ((sockfd = get_socket()) < 0)
 163                 exit(EXIT_FAILURE);
 164         /* init their_addr */
 165         init_sockaddr(&their_addr, args_info.server_port_arg, he);
 166         /* Connect */
 167         PARA_NOTICE_LOG("connecting to %s...\n",
 168                 args_info.hostname_arg);
 169         if (para_connect(sockfd, &their_addr) < 0)
 170                 exit(EXIT_FAILURE);
 171         /* Receive Welcome message */
 172         if ((numbytes = recv_buffer(sockfd, buf, sizeof(buf))) < 0)
 173                 exit(EXIT_FAILURE);
 174         /* send auth command */
 175         auth_str = make_message("auth %s%s", args_info.plain_given?  "" : "rc4 ",
 176                 args_info.user_arg);
 177         PARA_INFO_LOG("<-- %s--> %s\n", buf, auth_str);
 178         if (send_buffer(sockfd, auth_str) < 0)
 179                 exit(EXIT_FAILURE);
 180         /* receive challenge number */
 181         if ((numbytes = recv_buffer(sockfd, buf, sizeof(buf))) < 0)
 182                 exit(EXIT_FAILURE);
 183         if (numbytes != 64) {
 184                 PARA_EMERG_LOG("did not receive valid challenge (got %i bytes)\n",
 185                         numbytes);
 186                 buf[numbytes] = '\0';
 187                 PARA_ERROR_LOG("received the following instead: %s\n", buf);
 188                 exit(EXIT_FAILURE);
 189         }
 190         PARA_INFO_LOG("<-- [challenge (%i bytes)]\n", numbytes);
 191         /* decrypt challenge number */
 192         ret = para_decrypt_challenge(key_file, &challenge_nr, (unsigned char *) buf,
 193                 numbytes);
 194         if (ret < 0) {
 195                 PARA_EMERG_LOG("decrypt error (%d). Bad secret key?\n", ret);
 196                 exit(EXIT_FAILURE);
 197         }
 198         /* send decrypted challenge */
 199         PARA_INFO_LOG("--> %lu\n", challenge_nr);
 200         if (send_va_buffer(sockfd, "%s%lu", CHALLENGE_RESPONSE_MSG, challenge_nr) < 0)
 201                 exit(EXIT_FAILURE);
 202         /* Wait for approval */
 203         PARA_NOTICE_LOG("%s", "waiting for approval from server\n");
 204         if ((numbytes = recv_buffer(sockfd, buf, sizeof(buf))) < 0)
 205                 exit(EXIT_FAILURE);
 206         PARA_INFO_LOG("++++ server info ++++\n%s\n++++ end of server "
 207                 "info ++++\n", buf);
 208         /* Check if server has sent "Proceed" message */
 209         if (!strstr(buf, PROCEED_MSG)) {
 210                 PARA_EMERG_LOG("%s", "authentication failed\n");
 211                 exit(EXIT_FAILURE);
 212         }
 213         if (numbytes >= PROCEED_MSG_LEN + 32) {
 214                 PARA_INFO_LOG("%s", "decrypting session key\n");
 215                 if (para_decrypt_buffer(key_file, rc4_buf,
 216                                 (unsigned char *)buf + PROCEED_MSG_LEN + 1,
 217                                 numbytes - PROCEED_MSG_LEN - 1) < 0) {
 218                         PARA_EMERG_LOG("%s", "error receiving rc4 key\n");
 219                         exit(EXIT_FAILURE);
 220                 }
 221                 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf);
 222                 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 223                 PARA_INFO_LOG("rc4 encrytion activated: %x:%x:%x:%x\n",
 224                         rc4_buf[0], rc4_buf[1], rc4_buf[2], rc4_buf[3]);
 225                 crypt_function_recv = rc4_recv;
 226                 crypt_function_send = rc4_send;
 227         }
 228         /* send command */
 229         PARA_INFO_LOG("--> %s\n", command);
 230         if (send_buffer(sockfd, command) < 0)
 231                 exit(EXIT_FAILURE);
 232         free(command);
 233         command = NULL;
 234         if (send_buffer(sockfd, EOC_MSG "\n") < 0)
 235                 exit(EXIT_FAILURE);
 236         PARA_NOTICE_LOG("%s", "command sent.\n");
 237         received = 0;
 238         while ((numbytes = recv_bin_buffer(sockfd, buf, sizeof(buf) - 1)) > 0) {
 239                 buf[numbytes] = '\0';
 240                 if (!received && strstr(buf, AWAITING_DATA_MSG)) {
 241                         PARA_NOTICE_LOG("%s", "sending stdin\n");
 242                         while ((ret = read(STDIN_FILENO, buf,
 243                                         sizeof(buf))) > 0) {
 244                                 if (send_bin_buffer(sockfd, buf, ret) < 0)
 245                                         break;
 246                         }
 247                         PARA_NOTICE_LOG("%s", "closing connection\n");
 248                         numbytes = 1;
 249                         break;
 250                 }
 251                 received = 1;
 252                 if (write(STDOUT_FILENO, buf, numbytes) != numbytes)
 253                         break;
 254         }
 255         if (!numbytes)
 256                 PARA_NOTICE_LOG("%s", "connection closed by peer\n");
 257         close(sockfd);
 258         return ret >= 0? 0: 1;
 259 }