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 enum {CL_CONNECTED, CL_SENT_AUTH, CL_RECEIVED_CHALLENGE, CL_SENT_CH_RESPONSE,
  32         CL_RECEIVED_PROCEED, CL_SENT_COMMAND, CL_SENDING_STDIN, CL_RECV_DATA};
  33
  34 struct private_client_data {
  35         int status;
  36         int fd;
  37         struct client_args_info conf;
  38         char *config_file;
  39         char *key_file;
  40         char *user;
  41         char *in_buf;
  42         size_t *in_loaded;
  43         char *out_buf;
  44         size_t *out_loaded;
  45 };
  46
  47 INIT_CLIENT_ERRLISTS;
  48
  49 static struct private_client_data *pcd;
  50
  51 /*
  52  * client log function
  53  */
  54 void para_log(int ll, const char* fmt,...)
  55 {
  56         va_list argp;
  57
  58         /* ignore log message if loglevel is not high enough */
  59         if (pcd && ll < pcd->conf.loglevel_arg)
  60                 return;
  61         va_start(argp, fmt);
  62         vfprintf(stderr, fmt, argp);
  63         va_end(argp);
  64 }
  65
  66 static void client_close(struct private_client_data *pcd)
  67 {
  68         if (pcd)
  69                 return;
  70         if (pcd->fd >= 0)
  71                 close(pcd->fd);
  72         free(pcd->user);
  73         free(pcd->config_file);
  74         free(pcd->key_file);
  75         free(pcd);
  76 }
  77
  78 static int client_parse_config(int argc, char *argv[],
  79                 struct private_client_data **pcd_ptr)
  80 {
  81         char *home = para_homedir();
  82         struct stat statbuf;
  83         int ret;
  84         struct private_client_data *p =
  85                 para_calloc(sizeof(struct private_client_data));
  86
  87         p->fd = -1;
  88         cmdline_parser(argc, argv, &p->conf);
  89         ret = - E_CLIENT_SYNTAX;
  90         if (!p->conf.inputs_num)
  91                 goto out;
  92         p->user = p->conf.user_given?
  93                 para_strdup(p->conf.user_arg) : para_logname();
  94
  95         p->key_file = p->conf.key_file_given?
  96                 para_strdup(p->conf.key_file_arg) :
  97                 make_message("%s/.paraslash/key.%s", home, p->user);
  98
  99         p->config_file = p->conf.config_file_given?
 100                 para_strdup(p->conf.config_file_arg) :
 101                 make_message("%s/.paraslash/client.conf", home);
 102         ret = stat(p->config_file, &statbuf);
 103         if (ret && p->conf.config_file_given) {
 104                 ret = -E_NO_CONFIG;
 105                 goto out;
 106         }
 107         if (!ret)
 108                 cmdline_parser_configfile(p->config_file, &p->conf, 0, 0, 0);
 109         ret = 1;
 110 out:
 111         free(home);
 112         if (ret < 0)
 113                 client_close(p);
 114         else
 115                 *pcd_ptr = p;
 116         return ret;
 117 }
 118
 119 static RC4_KEY rc4_recv_key;
 120 static RC4_KEY rc4_send_key;
 121 static unsigned char rc4_buf[2 * RC4_KEY_LEN];
 122
 123 static void rc4_send(unsigned long len, const unsigned char *indata, unsigned char *outdata)
 124 {
 125         RC4(&rc4_send_key, len, indata, outdata);
 126 }
 127
 128 static void rc4_recv(unsigned long len, const unsigned char *indata, unsigned char *outdata)
 129 {
 130         RC4(&rc4_recv_key, len, indata, outdata);
 131 }
 132 void (*crypt_function_recv)(unsigned long len, const unsigned char *indata, unsigned char *outdata);
 133 void (*crypt_function_send)(unsigned long len, const unsigned char *indata, unsigned char *outdata);
 134
 135
 136 static void append_str(char **data, const char* append)
 137 {
 138         if (*data) {
 139                 char *tmp = make_message("%s\n%s", *data, append);
 140                 free(*data);
 141                 *data = tmp;
 142         } else
 143                 *data = para_strdup(append);
 144 }
 145
 146
 147 static int send_stdin(int fd)
 148 {
 149         char buf[8192];
 150         int ret;
 151
 152         PARA_NOTICE_LOG("%s", "sending stdin\n");
 153         for (;;) {
 154                 ret = read(STDIN_FILENO, buf, sizeof(buf));
 155                 if (ret <= 0)
 156                         return ret;
 157                 ret = send_bin_buffer(fd, buf, ret);
 158                 if (ret < 0)
 159                         return ret;
 160         }
 161         return 1;
 162 }
 163
 164 /*
 165  * MAIN
 166  */
 167 int main(int argc, char *argv[])
 168 {
 169
 170         int numbytes, i, received, ret;
 171         struct hostent *he;
 172         struct sockaddr_in their_addr;
 173         char *command = NULL;
 174         char buf[8192];
 175         char *auth_str;
 176         long unsigned challenge_nr;
 177
 178         ret = client_parse_config(argc, argv, &pcd);
 179         if (ret < 0)
 180                 goto out;
 181         if (pcd->conf.loglevel_arg <= NOTICE)
 182                 cmdline_parser_print_version();
 183         PARA_INFO_LOG(
 184                 "current loglevel: %d\n"
 185                 "using config_file: %s\n"
 186                 "using key_file: %s\n"
 187                 "connecting to %s:%d\n",
 188                 pcd->conf.loglevel_arg,
 189                 pcd->config_file,
 190                 pcd->key_file,
 191                 pcd->conf.hostname_arg,
 192                 pcd->conf.server_port_arg
 193         );
 194         /* concat args */
 195         for (i = 0; i < pcd->conf.inputs_num; i++)
 196                 append_str(&command, pcd->conf.inputs[i]);
 197         crypt_function_recv = NULL;
 198         crypt_function_send = NULL;
 199         /* get the host info */
 200         PARA_NOTICE_LOG("getting host info of %s\n",
 201                 pcd->conf.hostname_arg);
 202         ret = get_host_info(pcd->conf.hostname_arg, &he);
 203         if (ret < 0)
 204                 goto out;
 205         /* get new socket */
 206         ret = get_socket();
 207         if (ret < 0)
 208                 goto out;
 209         pcd->fd = ret;
 210         /* init their_addr */
 211         init_sockaddr(&their_addr, pcd->conf.server_port_arg, he);
 212         /* connect */
 213         PARA_NOTICE_LOG("connecting to %s\n", pcd->conf.hostname_arg);
 214         ret = para_connect(pcd->fd, &their_addr);
 215         if (ret < 0)
 216                 goto out;
 217         /* receive welcome message */
 218         ret = recv_buffer(pcd->fd, buf, sizeof(buf));
 219         if (ret < 0)
 220                 goto out;
 221         /* send auth command */
 222         auth_str = make_message("auth %s%s", pcd->conf.plain_given?  "" : "rc4 ",
 223                 pcd->user);
 224         PARA_INFO_LOG("<-- %s--> %s\n", buf, auth_str);
 225         ret = send_buffer(pcd->fd, auth_str);
 226         if (ret < 0)
 227                 goto out;
 228         /* receive challenge number */
 229         ret = recv_buffer(pcd->fd, buf, sizeof(buf));
 230         if (ret < 0)
 231                 goto out;
 232         if (ret != 64) {
 233                 ret = -E_INVALID_CHALLENGE;
 234                 PARA_ERROR_LOG("received the following: %s\n", buf);
 235                 goto out;
 236         }
 237         PARA_INFO_LOG("%s", "<-- [challenge]\n");
 238         /* decrypt challenge number */
 239         ret = para_decrypt_challenge(pcd->key_file, &challenge_nr,
 240                 (unsigned char *) buf, 64);
 241         if (ret < 0)
 242                 goto out;
 243         /* send decrypted challenge */
 244         PARA_INFO_LOG("--> %lu\n", challenge_nr);
 245         ret = send_va_buffer(pcd->fd, "%s%lu", CHALLENGE_RESPONSE_MSG, challenge_nr);
 246         if (ret < 0)
 247                 goto out;
 248         /* wait for approval */
 249         PARA_NOTICE_LOG("%s", "waiting for approval from server\n");
 250         ret = recv_buffer(pcd->fd, buf, sizeof(buf));
 251         if (ret < 0)
 252                 goto out;
 253         numbytes = ret;
 254         PARA_INFO_LOG("++++ server info ++++\n%s\n++++ end of server "
 255                 "info ++++\n", buf);
 256         /* check if server has sent "Proceed" message */
 257         ret = -E_CLIENT_AUTH;
 258         if (!strstr(buf, PROCEED_MSG))
 259                 goto out;
 260         if (numbytes >= PROCEED_MSG_LEN + 32) {
 261                 PARA_INFO_LOG("%s", "decrypting session key\n");
 262                 ret = para_decrypt_buffer(pcd->key_file, rc4_buf,
 263                         (unsigned char *)buf + PROCEED_MSG_LEN + 1,
 264                         numbytes - PROCEED_MSG_LEN - 1);
 265                 if (ret < 0)
 266                         goto out;
 267                 RC4_set_key(&rc4_send_key, RC4_KEY_LEN, rc4_buf);
 268                 RC4_set_key(&rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 269                 PARA_INFO_LOG("rc4 encrytion activated: %x:%x:%x:%x\n",
 270                         rc4_buf[0], rc4_buf[1], rc4_buf[2], rc4_buf[3]);
 271                 crypt_function_recv = rc4_recv;
 272                 crypt_function_send = rc4_send;
 273         }
 274         /* send command */
 275         PARA_INFO_LOG("--> %s\n", command);
 276         ret = send_buffer(pcd->fd, command);
 277         if (ret < 0)
 278                 goto out;
 279         free(command);
 280         command = NULL;
 281         ret = send_buffer(pcd->fd, EOC_MSG "\n");
 282         if (ret < 0)
 283                 goto out;
 284         PARA_NOTICE_LOG("%s", "command sent.\n");
 285         received = 0;
 286         for (;;) {
 287                 ret = recv_bin_buffer(pcd->fd, buf, sizeof(buf) - 1);
 288                 if (ret <= 0) {
 289                         if (!ret)
 290                                 PARA_NOTICE_LOG("%s", "connection closed by peer\n");
 291                         goto out;
 292                 }
 293                 buf[ret] = '\0';
 294                 numbytes = ret;
 295                 if (!received && strstr(buf, AWAITING_DATA_MSG)) {
 296                         ret = send_stdin(pcd->fd);
 297                         goto out;
 298                 }
 299                 received = 1;
 300                 ret = write(STDOUT_FILENO, buf, numbytes);
 301                 if (ret != numbytes) {
 302                         ret = -E_SHORT_CLIENT_WRITE;
 303                         goto out;
 304                 }
 305         }
 306         client_close(pcd);
 307 out:
 308         if (ret < 0)
 309                 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 310         return ret >= 0? EXIT_SUCCESS: EXIT_FAILURE;
 311 }