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         RC4_KEY rc4_recv_key;
  42         RC4_KEY rc4_send_key;
  43
  44         char *in_buf;
  45         size_t *in_loaded;
  46         char *out_buf;
  47         size_t *out_loaded;
  48 };
  49
  50 INIT_CLIENT_ERRLISTS;
  51
  52 static struct private_client_data *pcd;
  53
  54 /*
  55  * client log function
  56  */
  57 void para_log(int ll, const char* fmt,...)
  58 {
  59         va_list argp;
  60
  61         /* ignore log message if loglevel is not high enough */
  62         if (pcd && ll < pcd->conf.loglevel_arg)
  63                 return;
  64         va_start(argp, fmt);
  65         vfprintf(stderr, fmt, argp);
  66         va_end(argp);
  67 }
  68
  69 static void client_close(struct private_client_data *pcd)
  70 {
  71         if (pcd)
  72                 return;
  73         if (pcd->fd >= 0)
  74                 close(pcd->fd);
  75         free(pcd->user);
  76         free(pcd->config_file);
  77         free(pcd->key_file);
  78         free(pcd);
  79 }
  80
  81 static int client_parse_config(int argc, char *argv[],
  82                 struct private_client_data **pcd_ptr)
  83 {
  84         char *home = para_homedir();
  85         struct stat statbuf;
  86         int ret;
  87         struct private_client_data *p =
  88                 para_calloc(sizeof(struct private_client_data));
  89
  90         p->fd = -1;
  91         cmdline_parser(argc, argv, &p->conf);
  92         ret = - E_CLIENT_SYNTAX;
  93         if (!p->conf.inputs_num)
  94                 goto out;
  95         p->user = p->conf.user_given?
  96                 para_strdup(p->conf.user_arg) : para_logname();
  97
  98         p->key_file = p->conf.key_file_given?
  99                 para_strdup(p->conf.key_file_arg) :
 100                 make_message("%s/.paraslash/key.%s", home, p->user);
 101
 102         p->config_file = p->conf.config_file_given?
 103                 para_strdup(p->conf.config_file_arg) :
 104                 make_message("%s/.paraslash/client.conf", home);
 105         ret = stat(p->config_file, &statbuf);
 106         if (ret && p->conf.config_file_given) {
 107                 ret = -E_NO_CONFIG;
 108                 goto out;
 109         }
 110         if (!ret)
 111                 cmdline_parser_configfile(p->config_file, &p->conf, 0, 0, 0);
 112         ret = 1;
 113 out:
 114         free(home);
 115         if (ret < 0)
 116                 client_close(p);
 117         else
 118                 *pcd_ptr = p;
 119         return ret;
 120 }
 121
 122 static void rc4_send(unsigned long len, const unsigned char *indata,
 123                 unsigned char *outdata)
 124 {
 125         RC4(&pcd->rc4_send_key, len, indata, outdata);
 126 }
 127
 128 static void rc4_recv(unsigned long len, const unsigned char *indata,
 129                 unsigned char *outdata)
 130 {
 131         RC4(&pcd->rc4_recv_key, len, indata, outdata);
 132 }
 133
 134 void (*crypt_function_recv)(unsigned long len, const unsigned char *indata, unsigned char *outdata);
 135 void (*crypt_function_send)(unsigned long len, const unsigned char *indata, unsigned char *outdata);
 136
 137
 138 static void append_str(char **data, const char* append)
 139 {
 140         if (*data) {
 141                 char *tmp = make_message("%s\n%s", *data, append);
 142                 free(*data);
 143                 *data = tmp;
 144         } else
 145                 *data = para_strdup(append);
 146 }
 147
 148
 149 static int send_stdin(int fd)
 150 {
 151         char buf[8192];
 152         int ret;
 153
 154         PARA_NOTICE_LOG("%s", "sending stdin\n");
 155         for (;;) {
 156                 ret = read(STDIN_FILENO, buf, sizeof(buf));
 157                 if (ret <= 0)
 158                         return ret;
 159                 ret = send_bin_buffer(fd, buf, ret);
 160                 if (ret < 0)
 161                         return ret;
 162         }
 163         return 1;
 164 }
 165
 166 /*
 167  * MAIN
 168  */
 169 int main(int argc, char *argv[])
 170 {
 171
 172         int numbytes, i, received, ret;
 173         struct hostent *he;
 174         struct sockaddr_in their_addr;
 175         char *command = NULL;
 176         char buf[8192];
 177         char *auth_str;
 178         long unsigned challenge_nr;
 179         unsigned char rc4_buf[2 * RC4_KEY_LEN] = "";
 180
 181         ret = client_parse_config(argc, argv, &pcd);
 182         if (ret < 0)
 183                 goto out;
 184         if (pcd->conf.loglevel_arg <= NOTICE)
 185                 cmdline_parser_print_version();
 186         PARA_INFO_LOG(
 187                 "current loglevel: %d\n"
 188                 "using config_file: %s\n"
 189                 "using key_file: %s\n"
 190                 "connecting to %s:%d\n",
 191                 pcd->conf.loglevel_arg,
 192                 pcd->config_file,
 193                 pcd->key_file,
 194                 pcd->conf.hostname_arg,
 195                 pcd->conf.server_port_arg
 196         );
 197         /* concat args */
 198         for (i = 0; i < pcd->conf.inputs_num; i++)
 199                 append_str(&command, pcd->conf.inputs[i]);
 200         crypt_function_recv = NULL;
 201         crypt_function_send = NULL;
 202         /* get the host info */
 203         PARA_NOTICE_LOG("getting host info of %s\n",
 204                 pcd->conf.hostname_arg);
 205         ret = get_host_info(pcd->conf.hostname_arg, &he);
 206         if (ret < 0)
 207                 goto out;
 208         /* get new socket */
 209         ret = get_socket();
 210         if (ret < 0)
 211                 goto out;
 212         pcd->fd = ret;
 213         /* init their_addr */
 214         init_sockaddr(&their_addr, pcd->conf.server_port_arg, he);
 215         /* connect */
 216         PARA_NOTICE_LOG("connecting to %s\n", pcd->conf.hostname_arg);
 217         ret = para_connect(pcd->fd, &their_addr);
 218         if (ret < 0)
 219                 goto out;
 220         /* receive welcome message */
 221         ret = recv_buffer(pcd->fd, buf, sizeof(buf));
 222         if (ret < 0)
 223                 goto out;
 224         /* send auth command */
 225         auth_str = make_message("auth %s%s", pcd->conf.plain_given?  "" : "rc4 ",
 226                 pcd->user);
 227         PARA_INFO_LOG("<-- %s--> %s\n", buf, auth_str);
 228         ret = send_buffer(pcd->fd, auth_str);
 229         if (ret < 0)
 230                 goto out;
 231         /* receive challenge number */
 232         ret = recv_buffer(pcd->fd, buf, sizeof(buf));
 233         if (ret < 0)
 234                 goto out;
 235         if (ret != 64) {
 236                 ret = -E_INVALID_CHALLENGE;
 237                 PARA_ERROR_LOG("received the following: %s\n", buf);
 238                 goto out;
 239         }
 240         PARA_INFO_LOG("%s", "<-- [challenge]\n");
 241         /* decrypt challenge number */
 242         ret = para_decrypt_challenge(pcd->key_file, &challenge_nr,
 243                 (unsigned char *) buf, 64);
 244         if (ret < 0)
 245                 goto out;
 246         /* send decrypted challenge */
 247         PARA_INFO_LOG("--> %lu\n", challenge_nr);
 248         ret = send_va_buffer(pcd->fd, "%s%lu", CHALLENGE_RESPONSE_MSG, challenge_nr);
 249         if (ret < 0)
 250                 goto out;
 251         /* wait for approval */
 252         PARA_NOTICE_LOG("%s", "waiting for approval from server\n");
 253         ret = recv_buffer(pcd->fd, buf, sizeof(buf));
 254         if (ret < 0)
 255                 goto out;
 256         numbytes = ret;
 257         PARA_INFO_LOG("++++ server info ++++\n%s\n++++ end of server "
 258                 "info ++++\n", buf);
 259         /* check if server has sent "Proceed" message */
 260         ret = -E_CLIENT_AUTH;
 261         if (!strstr(buf, PROCEED_MSG))
 262                 goto out;
 263         if (numbytes >= PROCEED_MSG_LEN + 32) {
 264                 PARA_INFO_LOG("%s", "decrypting session key\n");
 265                 ret = para_decrypt_buffer(pcd->key_file, rc4_buf,
 266                         (unsigned char *)buf + PROCEED_MSG_LEN + 1,
 267                         numbytes - PROCEED_MSG_LEN - 1);
 268                 if (ret < 0)
 269                         goto out;
 270                 RC4_set_key(&pcd->rc4_send_key, RC4_KEY_LEN, rc4_buf);
 271                 RC4_set_key(&pcd->rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 272                 PARA_INFO_LOG("rc4 encrytion activated: %x:%x:%x:%x\n",
 273                         rc4_buf[0], rc4_buf[1], rc4_buf[2], rc4_buf[3]);
 274                 crypt_function_recv = rc4_recv;
 275                 crypt_function_send = rc4_send;
 276         }
 277         /* send command */
 278         PARA_INFO_LOG("--> %s\n", command);
 279         ret = send_buffer(pcd->fd, command);
 280         if (ret < 0)
 281                 goto out;
 282         free(command);
 283         command = NULL;
 284         ret = send_buffer(pcd->fd, EOC_MSG "\n");
 285         if (ret < 0)
 286                 goto out;
 287         PARA_NOTICE_LOG("%s", "command sent.\n");
 288         received = 0;
 289         for (;;) {
 290                 ret = recv_bin_buffer(pcd->fd, buf, sizeof(buf) - 1);
 291                 if (ret <= 0) {
 292                         if (!ret)
 293                                 PARA_NOTICE_LOG("%s", "connection closed by peer\n");
 294                         goto out;
 295                 }
 296                 buf[ret] = '\0';
 297                 numbytes = ret;
 298                 if (!received && strstr(buf, AWAITING_DATA_MSG)) {
 299                         ret = send_stdin(pcd->fd);
 300                         goto out;
 301                 }
 302                 received = 1;
 303                 ret = write(STDOUT_FILENO, buf, numbytes);
 304                 if (ret != numbytes) {
 305                         ret = -E_SHORT_CLIENT_WRITE;
 306                         goto out;
 307                 }
 308         }
 309         client_close(pcd);
 310 out:
 311         if (ret < 0)
 312                 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 313         return ret >= 0? EXIT_SUCCESS: EXIT_FAILURE;
 314 }