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 <readline/readline.h>
  24 #include <readline/history.h>
  25 #include "client.cmdline.h"
  26 #include "crypt.h"
  27 #include "rc4.h"
  28 #include <openssl/rc4.h>
  29 #include "net.h"
  30 #include "string.h"
  31
  32 /* A static variable for holding the line. */
  33 static char *line_read;
  34
  35 struct gengetopt_args_info args_info;
  36
  37 /*
  38  * client log function
  39  */
  40 void para_log(int ll, char* fmt,...)
  41 {
  42         va_list argp;
  43         FILE *outfd;
  44
  45         /* ignore log message if loglevel is not high enough */
  46         if (ll < args_info.loglevel_arg)
  47                 return;
  48         if (ll < WARNING)
  49                 outfd = stdout;
  50         else
  51                 outfd = stderr;
  52         va_start(argp, fmt);
  53         vfprintf(stdout, fmt, argp);
  54         va_end(argp);
  55 }
  56
  57 /*
  58  * Read a string, and return a pointer to it. Returns NULL on EOF.
  59  */
  60 static char *rl_gets(void)
  61 {
  62         free(line_read);
  63         /* Get a line from the user. */
  64         line_read = readline("para_client> ");
  65         /* If the line has any text in it, save it on the history. */
  66         if (line_read && *line_read)
  67                 add_history(line_read);
  68         return line_read;
  69 }
  70
  71 /*
  72  * do several cleanups on sigint
  73  */
  74 static void sigint_handler(__unused int i)
  75 {
  76         rl_cleanup_after_signal();
  77         rl_reset_after_signal();
  78 }
  79
  80 void get_options(int argc, char *argv[],
  81         char **config_file, char **key_file)
  82 {
  83         char *home;
  84         static char default_key_file[_POSIX_PATH_MAX] = "";
  85         static char default_config_file[_POSIX_PATH_MAX] = "";
  86         struct stat statbuf;
  87         int ret;
  88
  89         cmdline_parser(argc, argv, &args_info);
  90         if (!args_info.user_given)
  91                 args_info.user_arg = para_logname();
  92         if (!args_info.key_file_given) {
  93                 home = para_homedir();
  94                 sprintf(default_key_file, "%s/.paraslash/key.%s", home,
  95                         args_info.user_arg);
  96                 free(home);
  97         }
  98         if (!args_info.config_file_given) {
  99                 home = para_homedir();
 100                 sprintf(default_config_file, "%s/.paraslash/client.conf",
 101                         home);
 102                 free(home);
 103         }
 104         if (!args_info.config_file_given)
 105                 *config_file = default_config_file;
 106         else
 107                 *config_file = args_info.config_file_arg;
 108         ret = stat(*config_file, &statbuf);
 109         if (ret && args_info.config_file_given) {
 110                 fprintf(stderr, "can not stat config file %s\n",
 111                         args_info.config_file_arg);
 112                 exit(EXIT_FAILURE);
 113         }
 114         if (!ret)
 115                 cmdline_parser_configfile(*config_file, &args_info, 0, 0, 0);
 116         if (!args_info.key_file_given)
 117                 *key_file = default_key_file;
 118         else
 119                 *key_file = args_info.key_file_arg;
 120 }
 121
 122 static RC4_KEY rc4_recv_key;
 123 static RC4_KEY rc4_send_key;
 124 static unsigned char rc4_buf[2 * RC4_KEY_LEN];
 125
 126 static void rc4_send(unsigned long len, const unsigned char *indata, unsigned char *outdata)
 127 {
 128         RC4(&rc4_send_key, len, indata, outdata);
 129 }
 130
 131 static void rc4_recv(unsigned long len, const unsigned char *indata, unsigned char *outdata)
 132 {
 133         RC4(&rc4_recv_key, len, indata, outdata);
 134 }
 135 void (*crypt_function_recv)(unsigned long len, const unsigned char *indata, unsigned char *outdata);
 136 void (*crypt_function_send)(unsigned long len, const unsigned char *indata, unsigned char *outdata);
 137
 138
 139 static void append_str(char **data, const char* append)
 140 {
 141         if (*data) {
 142                 char *tmp = make_message("%s\n%s", *data, append);
 143                 free(*data);
 144                 *data = tmp;
 145         } else
 146                 *data = para_strdup(append);
 147 }
 148
 149 /*
 150  * MAIN
 151  */
 152 int main(int argc, char *argv[])
 153 {
 154
 155         int sockfd, numbytes, i, interactive, received, ret;
 156         struct hostent *he;
 157         struct sockaddr_in their_addr;
 158         char *command = NULL;
 159         char buf[8192];
 160         char *auth_str;
 161         char *key_file, *config_file;
 162         long unsigned challenge_nr;
 163         char *line;
 164
 165         get_options(argc, argv, &config_file, &key_file);
 166         if (args_info.loglevel_arg <= NOTICE)
 167                 cmdline_parser_print_version();
 168         PARA_INFO_LOG(
 169                 "current loglevel: %d\n"
 170                 "using config_file: %s\n"
 171                 "using key_file: %s\n"
 172                 "connecting to %s:%d\n",
 173                 args_info.loglevel_arg,
 174                 config_file,
 175                 key_file,
 176                 args_info.hostname_arg,
 177                 args_info.server_port_arg
 178         );
 179         interactive = args_info.inputs_num == 0? 1 : 0;
 180         if (interactive) {
 181                 PARA_NOTICE_LOG("%s", "no command, entering interactive mode\n");
 182                 signal(SIGINT, sigint_handler);
 183         } else {
 184                 /* not interactive, concat args */
 185                 for (i = 0; i < args_info.inputs_num; i++)
 186                         append_str(&command, args_info.inputs[i]);
 187         }
 188 interactive_loop:
 189         crypt_function_recv = NULL;
 190         crypt_function_send = NULL;
 191         if (interactive) {
 192                 int i = 0;
 193                 char *p;
 194
 195                 rl_save_prompt();
 196                 rl_message("\n");
 197                 rl_kill_full_line(0, 0);
 198                 rl_free_line_state();
 199                 /* read a line via readline */
 200                 line = rl_gets();
 201                 if (!line)
 202                         return 0;
 203                 if (!line[0])
 204                         goto interactive_loop;
 205                 p = line;
 206                 while (sscanf(p, "%200s%n", buf, &i) == 1) {
 207                         append_str(&command, buf);
 208                         p += i;
 209                 }
 210         }
 211         /* get the host info */
 212         PARA_NOTICE_LOG("getting host info of %s\n",
 213                 args_info.hostname_arg);
 214         if (!(he = get_host_info(args_info.hostname_arg)))
 215                 exit(EXIT_FAILURE);
 216         /* get new socket */
 217         if ((sockfd = get_socket()) < 0)
 218                 exit(EXIT_FAILURE);
 219         /* init their_addr */
 220         init_sockaddr(&their_addr, args_info.server_port_arg, he);
 221         /* Connect */
 222         PARA_NOTICE_LOG("connecting to %s...\n",
 223                 args_info.hostname_arg);
 224         if (para_connect(sockfd, &their_addr) < 0)
 225                 exit(EXIT_FAILURE);
 226         /* Receive Welcome message */
 227         if ((numbytes = recv_buffer(sockfd, buf, sizeof(buf))) < 0)
 228                 exit(EXIT_FAILURE);
 229         /* send auth command */
 230         auth_str = make_message("auth %s%s", args_info.plain_given?  "" : "rc4 ",
 231                 args_info.user_arg);
 232         PARA_INFO_LOG("<-- %s--> %s\n", buf, auth_str);
 233         if (send_buffer(sockfd, auth_str) < 0)
 234                 exit(EXIT_FAILURE);
 235         /* receive challenge number */
 236         if ((numbytes = recv_buffer(sockfd, buf, sizeof(buf))) < 0)
 237                 exit(EXIT_FAILURE);
 238         if (numbytes != 64) {
 239                 PARA_EMERG_LOG("did not receive valid challenge (got %i bytes)\n",
 240                         numbytes);
 241                 buf[numbytes] = '\0';
 242                 PARA_ERROR_LOG("received the following instead: %s\n", buf);
 243                 goto write_out;
 244         }
 245         PARA_INFO_LOG("<-- [challenge (%i bytes)]\n", numbytes);
 246         /* decrypt challenge number */
 247         ret = para_decrypt_challenge(key_file, &challenge_nr, (unsigned char *) buf,
 248                 numbytes);
 249         if (ret < 0) {
 250                 PARA_EMERG_LOG("decrypt error (%d). Bad secret key?\n", ret);
 251                 exit(EXIT_FAILURE);
 252         }
 253         /* send decrypted challenge */
 254         PARA_INFO_LOG("--> %lu\n", challenge_nr);
 255         if (send_va_buffer(sockfd, "%s%lu", CHALLENGE_RESPONSE_MSG, challenge_nr) < 0)
 256                 exit(EXIT_FAILURE);
 257         /* Wait for approval */
 258         PARA_NOTICE_LOG("%s", "waiting for approval from server\n");
 259         if ((numbytes = recv_buffer(sockfd, buf, sizeof(buf))) < 0)
 260                 exit(EXIT_FAILURE);
 261         PARA_INFO_LOG("++++ server info ++++\n%s\n++++ end of server "
 262                 "info ++++\n", buf);
 263         /* Check if server has sent "Proceed" message */
 264         if (!strstr(buf, PROCEED_MSG)) {
 265                 PARA_EMERG_LOG("%s", "authentication failed\n");
 266                 exit(EXIT_FAILURE);
 267         }
 268         if (numbytes >= PROCEED_MSG_LEN + 32) {
 269                 PARA_INFO_LOG("%s", "decrypting session key\n");
 270                 if (para_decrypt_buffer(key_file, rc4_buf,
 271                                 (unsigned char *)buf + PROCEED_MSG_LEN + 1,
 272                                 numbytes - PROCEED_MSG_LEN - 1) < 0) {
 273                         PARA_EMERG_LOG("%s", "error receiving rc4 key\n");
 274                         exit(EXIT_FAILURE);
 275                 }
 276                 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf);
 277                 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 278                 PARA_INFO_LOG("rc4 encrytion activated: %x:%x:%x:%x\n",
 279                         rc4_buf[0], rc4_buf[1], rc4_buf[2], rc4_buf[3]);
 280                 crypt_function_recv = rc4_recv;
 281                 crypt_function_send = rc4_send;
 282         }
 283         /* send command */
 284         PARA_INFO_LOG("--> %s\n", command);
 285         if (send_buffer(sockfd, command) < 0)
 286                 exit(EXIT_FAILURE);
 287         free(command);
 288         command = NULL;
 289         if (send_buffer(sockfd, EOC_MSG "\n") < 0)
 290                 exit(EXIT_FAILURE);
 291         PARA_NOTICE_LOG("%s", "command sent.\n");
 292 write_out:
 293         received = 0;
 294         /* write server output to stdout */
 295         while ((numbytes = recv_bin_buffer(sockfd, buf, sizeof(buf))) > 0) {
 296                 int ret;
 297
 298                 if (!received && strstr(buf, AWAITING_DATA_MSG)) {
 299                         PARA_NOTICE_LOG("%s", "<-- awaiting data\n");
 300                         PARA_NOTICE_LOG("%s", "--> sending stdin\n");
 301                         while ((ret = read(STDIN_FILENO, buf,
 302                                         sizeof(buf))) > 0)
 303                                 send_bin_buffer(sockfd, buf, ret);
 304                         PARA_NOTICE_LOG("%s", "closing connection\n");
 305                         numbytes = 1;
 306                         break;
 307                 }
 308                 received = 1;
 309                 if (write(STDOUT_FILENO, buf, numbytes) != numbytes)
 310                         break;
 311         }
 312         if (!numbytes)
 313                 PARA_NOTICE_LOG("%s", "connection closed by peer\n");
 314         close(sockfd);
 315         if (interactive)
 316                 goto interactive_loop;
 317         return 0;
 318 }