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 #include "error.h"
  30
  31 struct gengetopt_args_info args_info;
  32
  33 INIT_CLIENT_ERRLISTS;
  34
  35 /*
  36  * client log function
  37  */
  38 void para_log(int ll, const char* fmt,...)
  39 {
  40         va_list argp;
  41
  42         /* ignore log message if loglevel is not high enough */
  43         if (ll < args_info.loglevel_arg)
  44                 return;
  45         va_start(argp, fmt);
  46         vfprintf(stderr, fmt, argp);
  47         va_end(argp);
  48 }
  49
  50 static int get_options(int argc, char *argv[],
  51         char **config_file, char **key_file)
  52 {
  53         char *home;
  54         static char default_key_file[_POSIX_PATH_MAX] = "";
  55         static char default_config_file[_POSIX_PATH_MAX] = "";
  56         struct stat statbuf;
  57         int ret;
  58
  59         cmdline_parser(argc, argv, &args_info);
  60         if (!args_info.user_given)
  61                 args_info.user_arg = para_logname();
  62         if (!args_info.key_file_given) {
  63                 home = para_homedir();
  64                 sprintf(default_key_file, "%s/.paraslash/key.%s", home,
  65                         args_info.user_arg);
  66                 free(home);
  67         }
  68         if (!args_info.config_file_given) {
  69                 home = para_homedir();
  70                 sprintf(default_config_file, "%s/.paraslash/client.conf",
  71                         home);
  72                 free(home);
  73         }
  74         if (!args_info.config_file_given)
  75                 *config_file = default_config_file;
  76         else
  77                 *config_file = args_info.config_file_arg;
  78         ret = stat(*config_file, &statbuf);
  79         if (ret && args_info.config_file_given)
  80                 return -E_NO_CONFIG;
  81         if (!ret)
  82                 cmdline_parser_configfile(*config_file, &args_info, 0, 0, 0);
  83         if (!args_info.key_file_given)
  84                 *key_file = default_key_file;
  85         else
  86                 *key_file = args_info.key_file_arg;
  87         return 1;
  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 static int send_stdin(int fd)
 119 {
 120         char buf[8192];
 121         int ret;
 122
 123         PARA_NOTICE_LOG("%s", "sending stdin\n");
 124         for (;;) {
 125                 ret = read(STDIN_FILENO, buf, sizeof(buf));
 126                 if (ret <= 0)
 127                         return ret;
 128                 ret = send_bin_buffer(fd, buf, ret);
 129                 if (ret < 0)
 130                         return ret;
 131         }
 132         return 1;
 133 }
 134 /*
 135  * MAIN
 136  */
 137 int main(int argc, char *argv[])
 138 {
 139
 140         int sockfd = -1, numbytes, i, received, ret;
 141         struct hostent *he;
 142         struct sockaddr_in their_addr;
 143         char *command = NULL;
 144         char buf[8192];
 145         char *auth_str;
 146         char *key_file, *config_file;
 147         long unsigned challenge_nr;
 148
 149         ret = get_options(argc, argv, &config_file, &key_file);
 150         if (ret < 0)
 151                 goto out;
 152         if (args_info.loglevel_arg <= NOTICE)
 153                 cmdline_parser_print_version();
 154         PARA_INFO_LOG(
 155                 "current loglevel: %d\n"
 156                 "using config_file: %s\n"
 157                 "using key_file: %s\n"
 158                 "connecting to %s:%d\n",
 159                 args_info.loglevel_arg,
 160                 config_file,
 161                 key_file,
 162                 args_info.hostname_arg,
 163                 args_info.server_port_arg
 164         );
 165         ret = - E_CLIENT_SYNTAX;
 166         if (!args_info.inputs_num)
 167                 goto out;
 168         /* concat args */
 169         for (i = 0; i < args_info.inputs_num; i++)
 170                 append_str(&command, args_info.inputs[i]);
 171         crypt_function_recv = NULL;
 172         crypt_function_send = NULL;
 173         /* get the host info */
 174         PARA_NOTICE_LOG("getting host info of %s\n",
 175                 args_info.hostname_arg);
 176         ret = get_host_info(args_info.hostname_arg, &he);
 177         if (ret < 0)
 178                 goto out;
 179         /* get new socket */
 180         ret = get_socket();
 181         if (ret < 0)
 182                 goto out;
 183         sockfd = ret;
 184         /* init their_addr */
 185         init_sockaddr(&their_addr, args_info.server_port_arg, he);
 186         /* connect */
 187         PARA_NOTICE_LOG("connecting to %s\n", args_info.hostname_arg);
 188         ret = para_connect(sockfd, &their_addr);
 189         if (ret < 0)
 190                 goto out;
 191         /* receive welcome message */
 192         ret = recv_buffer(sockfd, buf, sizeof(buf));
 193         if (ret < 0)
 194                 goto out;
 195         /* send auth command */
 196         auth_str = make_message("auth %s%s", args_info.plain_given?  "" : "rc4 ",
 197                 args_info.user_arg);
 198         PARA_INFO_LOG("<-- %s--> %s\n", buf, auth_str);
 199         ret = send_buffer(sockfd, auth_str);
 200         if (ret < 0)
 201                 goto out;
 202         /* receive challenge number */
 203         ret = recv_buffer(sockfd, buf, sizeof(buf));
 204         if (ret < 0)
 205                 goto out;
 206         if (ret != 64) {
 207                 ret = -E_INVALID_CHALLENGE;
 208                 PARA_ERROR_LOG("received the following: %s\n", buf);
 209                 goto out;
 210         }
 211         PARA_INFO_LOG("%s", "<-- [challenge]\n");
 212         /* decrypt challenge number */
 213         ret = para_decrypt_challenge(key_file, &challenge_nr, (unsigned char *) buf, 64);
 214         if (ret < 0)
 215                 goto out;
 216         /* send decrypted challenge */
 217         PARA_INFO_LOG("--> %lu\n", challenge_nr);
 218         ret = send_va_buffer(sockfd, "%s%lu", CHALLENGE_RESPONSE_MSG, challenge_nr);
 219         if (ret < 0)
 220                 goto out;
 221         /* wait for approval */
 222         PARA_NOTICE_LOG("%s", "waiting for approval from server\n");
 223         ret = recv_buffer(sockfd, buf, sizeof(buf));
 224         if (ret < 0)
 225                 goto out;
 226         numbytes = ret;
 227         PARA_INFO_LOG("++++ server info ++++\n%s\n++++ end of server "
 228                 "info ++++\n", buf);
 229         /* check if server has sent "Proceed" message */
 230         ret = -E_CLIENT_AUTH;
 231         if (!strstr(buf, PROCEED_MSG))
 232                 goto out;
 233         if (numbytes >= PROCEED_MSG_LEN + 32) {
 234                 PARA_INFO_LOG("%s", "decrypting session key\n");
 235                 ret = para_decrypt_buffer(key_file, rc4_buf,
 236                         (unsigned char *)buf + PROCEED_MSG_LEN + 1,
 237                         numbytes - PROCEED_MSG_LEN - 1);
 238                 if (ret < 0)
 239                         goto out;
 240                 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf);
 241                 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 242                 PARA_INFO_LOG("rc4 encrytion activated: %x:%x:%x:%x\n",
 243                         rc4_buf[0], rc4_buf[1], rc4_buf[2], rc4_buf[3]);
 244                 crypt_function_recv = rc4_recv;
 245                 crypt_function_send = rc4_send;
 246         }
 247         /* send command */
 248         PARA_INFO_LOG("--> %s\n", command);
 249         ret = send_buffer(sockfd, command);
 250         if (ret < 0)
 251                 goto out;
 252         free(command);
 253         command = NULL;
 254         ret = send_buffer(sockfd, EOC_MSG "\n");
 255         if (ret < 0)
 256                 goto out;
 257         PARA_NOTICE_LOG("%s", "command sent.\n");
 258         received = 0;
 259         for (;;) {
 260                 ret = recv_bin_buffer(sockfd, buf, sizeof(buf) - 1);
 261                 if (ret <= 0) {
 262                         if (!ret)
 263                                 PARA_NOTICE_LOG("%s", "connection closed by peer\n");
 264                         goto out;
 265                 }
 266                 buf[ret] = '\0';
 267                 numbytes = ret;
 268                 if (!received && strstr(buf, AWAITING_DATA_MSG)) {
 269                         ret = send_stdin(sockfd);
 270                         goto out;
 271                 }
 272                 received = 1;
 273                 ret = write(STDOUT_FILENO, buf, numbytes);
 274                 if (ret != numbytes) {
 275                         ret = -E_SHORT_CLIENT_WRITE;
 276                         goto out;
 277                 }
 278         }
 279 out:
 280         if (sockfd >= 0)
 281                 close(sockfd);
 282         if (ret < 0)
 283                 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 284         return ret >= 0? EXIT_SUCCESS: EXIT_FAILURE;
 285 }