package/ead/src/ead-client.c

   1 /*
   2  * Client for the Emergency Access Daemon
   3  * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2
   7  * as published by the Free Software Foundation
   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
  15 #include <sys/types.h>
  16 #include <sys/socket.h>
  17 #include <sys/time.h>
  18 #include <netinet/in.h>
  19 #include <arpa/inet.h>
  20 #include <stdio.h>
  21 #include <stddef.h>
  22 #include <stdint.h>
  23 #include <stdlib.h>
  24 #include <stdbool.h>
  25 #include <string.h>
  26 #include <fcntl.h>
  27 #include <unistd.h>
  28 #include <t_pwd.h>
  29 #include <t_read.h>
  30 #include <t_sha.h>
  31 #include <t_defines.h>
  32 #include <t_client.h>
  33 #include "ead.h"
  34 #include "ead-crypt.h"
  35
  36 #include "pw_encrypt_md5.c"
  37
  38 #define EAD_TIMEOUT     400
  39 #define EAD_TIMEOUT_LONG 2000
  40
  41 static char msgbuf[1500];
  42 static struct ead_msg *msg = (struct ead_msg *) msgbuf;
  43 static uint16_t nid = 0xffff;
  44 struct sockaddr_in local, remote;
  45 static int s = 0;
  46 static int sockflags;
  47 static struct in_addr serverip = {
  48         .s_addr = 0x01010101 /* dummy */
  49 };
  50
  51 static unsigned char *skey = NULL;
  52 static unsigned char bbuf[MAXPARAMLEN];
  53 static unsigned char saltbuf[MAXSALTLEN];
  54 static char *username = NULL;
  55 static char password[MAXPARAMLEN] = "";
  56 static char pw_md5[MD5_OUT_BUFSIZE];
  57 static char pw_salt[MAXSALTLEN];
  58
  59 static struct t_client *tc = NULL;
  60 static struct t_num salt = { .data = saltbuf };
  61 static struct t_num *A, B;
  62 static struct t_preconf *tcp;
  63 static int auth_type = EAD_AUTH_DEFAULT;
  64 static int timeout = EAD_TIMEOUT;
  65 static uint16_t sid = 0;
  66
  67 static void
  68 set_nonblock(int enable)
  69 {
  70         if (enable == !!(sockflags & O_NONBLOCK));
  71                 return;
  72
  73         sockflags ^= O_NONBLOCK;
  74         fcntl(s, F_SETFL, sockflags);
  75 }
  76
  77 static int
  78 send_packet(int type, bool (*handler)(void), unsigned int max)
  79 {
  80         struct timeval tv;
  81         fd_set fds;
  82         int nfds;
  83         int len;
  84         int res = 0;
  85
  86         type = htonl(type);
  87         memcpy(&msg->ip, &serverip.s_addr, sizeof(msg->ip));
  88         set_nonblock(0);
  89         sendto(s, msgbuf, sizeof(struct ead_msg) + ntohl(msg->len), 0, (struct sockaddr *) &remote, sizeof(remote));
  90         set_nonblock(1);
  91
  92         tv.tv_sec = timeout / 1000;
  93         tv.tv_usec = (timeout % 1000) * 1000;
  94
  95         FD_ZERO(&fds);
  96         do {
  97                 FD_SET(s, &fds);
  98                 nfds = select(s + 1, &fds, NULL, NULL, &tv);
  99
 100                 if (nfds <= 0)
 101                         break;
 102
 103                 if (!FD_ISSET(s, &fds))
 104                         break;
 105
 106                 len = read(s, msgbuf, sizeof(msgbuf));
 107                 if (len < 0)
 108                         break;
 109
 110                 if (len < sizeof(struct ead_msg))
 111                         continue;
 112
 113                 if (len < sizeof(struct ead_msg) + ntohl(msg->len))
 114                         continue;
 115
 116                 if (msg->magic != htonl(EAD_MAGIC))
 117                         continue;
 118
 119                 if ((nid != 0xffff) && (ntohs(msg->nid) != nid))
 120                         continue;
 121
 122                 if (msg->type != type)
 123                         continue;
 124
 125                 if (handler())
 126                         res++;
 127
 128                 if ((max > 0) && (res >= max))
 129                         break;
 130         } while (1);
 131
 132         return res;
 133 }
 134
 135 static void
 136 prepare_password(void)
 137 {
 138         switch(auth_type) {
 139         case EAD_AUTH_DEFAULT:
 140                 break;
 141         case EAD_AUTH_MD5:
 142                 md5_crypt(pw_md5, (unsigned char *) password, (unsigned char *) pw_salt);
 143                 strncpy(password, pw_md5, sizeof(password));
 144                 break;
 145         }
 146 }
 147
 148 static bool
 149 handle_pong(void)
 150 {
 151         struct ead_msg_pong *pong = EAD_DATA(msg, pong);
 152         int len = ntohl(msg->len) - sizeof(struct ead_msg_pong);
 153
 154         if (len <= 0)
 155                 return false;
 156
 157         pong->name[len] = 0;
 158         auth_type = ntohs(pong->auth_type);
 159         if (nid == 0xffff)
 160                 printf("%04x: %s\n", ntohs(msg->nid), pong->name);
 161         sid = msg->sid;
 162         return true;
 163 }
 164
 165 static bool
 166 handle_prime(void)
 167 {
 168         struct ead_msg_salt *sb = EAD_DATA(msg, salt);
 169
 170         salt.len = sb->len;
 171         memcpy(salt.data, sb->salt, salt.len);
 172
 173         if (auth_type == EAD_AUTH_MD5) {
 174                 memcpy(pw_salt, sb->ext_salt, MAXSALTLEN);
 175                 pw_salt[MAXSALTLEN - 1] = 0;
 176         }
 177
 178         tcp = t_getpreparam(sb->prime);
 179         tc = t_clientopen(username, &tcp->modulus, &tcp->generator, &salt);
 180         if (!tc) {
 181                 fprintf(stderr, "Client open failed\n");
 182                 return false;
 183         }
 184
 185         return true;
 186 }
 187
 188 static bool
 189 handle_b(void)
 190 {
 191         struct ead_msg_number *num = EAD_DATA(msg, number);
 192         int len = ntohl(msg->len) - sizeof(struct ead_msg_number);
 193
 194         B.data = bbuf;
 195         B.len = len;
 196         memcpy(bbuf, num->data, len);
 197         return true;
 198 }
 199
 200 static bool
 201 handle_none(void)
 202 {
 203         return true;
 204 }
 205
 206 static bool
 207 handle_done_auth(void)
 208 {
 209         struct ead_msg_auth *auth = EAD_DATA(msg, auth);
 210         if (t_clientverify(tc, auth->data) != 0) {
 211                 fprintf(stderr, "Client auth verify failed\n");
 212                 return false;
 213         }
 214         return true;
 215 }
 216
 217 static bool
 218 handle_cmd_data(void)
 219 {
 220         struct ead_msg_cmd_data *cmd = EAD_ENC_DATA(msg, cmd_data);
 221         int datalen = ead_decrypt_message(msg) - sizeof(struct ead_msg_cmd_data);
 222
 223         if (datalen < 0)
 224                 return false;
 225
 226         if (datalen > 0) {
 227                 write(1, cmd->data, datalen);
 228         }
 229
 230         return !!cmd->done;
 231 }
 232 static int
 233 send_ping(void)
 234 {
 235         msg->type = htonl(EAD_TYPE_PING);
 236         msg->len = 0;
 237         return send_packet(EAD_TYPE_PONG, handle_pong, (nid == 0xffff ? 0 : 1));
 238 }
 239
 240 static int
 241 send_username(void)
 242 {
 243         msg->type = htonl(EAD_TYPE_SET_USERNAME);
 244         msg->len = htonl(sizeof(struct ead_msg_user));
 245         strcpy(EAD_DATA(msg, user)->username, username);
 246         return send_packet(EAD_TYPE_ACK_USERNAME, handle_none, 1);
 247 }
 248
 249 static int
 250 get_prime(void)
 251 {
 252         msg->type = htonl(EAD_TYPE_GET_PRIME);
 253         msg->len = 0;
 254         return send_packet(EAD_TYPE_PRIME, handle_prime, 1);
 255 }
 256
 257 static int
 258 send_a(void)
 259 {
 260         struct ead_msg_number *num = EAD_DATA(msg, number);
 261         A = t_clientgenexp(tc);
 262         msg->type = htonl(EAD_TYPE_SEND_A);
 263         msg->len = htonl(sizeof(struct ead_msg_number) + A->len);
 264         memcpy(num->data, A->data, A->len);
 265         return send_packet(EAD_TYPE_SEND_B, handle_b, 1);
 266 }
 267
 268 static int
 269 send_auth(void)
 270 {
 271         struct ead_msg_auth *auth = EAD_DATA(msg, auth);
 272
 273         prepare_password();
 274         t_clientpasswd(tc, password);
 275         skey = t_clientgetkey(tc, &B);
 276         if (!skey)
 277                 return 0;
 278
 279         ead_set_key(skey);
 280         msg->type = htonl(EAD_TYPE_SEND_AUTH);
 281         msg->len = htonl(sizeof(struct ead_msg_auth));
 282         memcpy(auth->data, t_clientresponse(tc), sizeof(auth->data));
 283         return send_packet(EAD_TYPE_DONE_AUTH, handle_done_auth, 1);
 284 }
 285
 286 static int
 287 send_command(const char *command)
 288 {
 289         struct ead_msg_cmd *cmd = EAD_ENC_DATA(msg, cmd);
 290
 291         msg->type = htonl(EAD_TYPE_SEND_CMD);
 292         cmd->type = htons(EAD_CMD_NORMAL);
 293         cmd->timeout = htons(10);
 294         strncpy((char *)cmd->data, command, 1024);
 295         ead_encrypt_message(msg, sizeof(struct ead_msg_cmd) + strlen(command) + 1);
 296         return send_packet(EAD_TYPE_RESULT_CMD, handle_cmd_data, 1);
 297 }
 298
 299
 300 static int
 301 usage(const char *prog)
 302 {
 303         fprintf(stderr, "Usage: %s [-s <addr>] [-b <addr>] <node> <username>[:<password>] <command>\n"
 304                 "\n"
 305                 "\t-s <addr>:  Set the server's source address to <addr>\n"
 306                 "\t-b <addr>:  Set the broadcast address to <addr>\n"
 307                 "\t<node>:     Node ID (4 digits hex)\n"
 308                 "\t<username>: Username to authenticate with\n"
 309                 "\n"
 310                 "\tPassing no arguments shows a list of active nodes on the network\n"
 311                 "\n", prog);
 312         return -1;
 313 }
 314
 315
 316 int main(int argc, char **argv)
 317 {
 318         int val = 1;
 319         char *st = NULL;
 320         const char *command = NULL;
 321         const char *prog = argv[0];
 322         int ch;
 323
 324         msg->magic = htonl(EAD_MAGIC);
 325         msg->sid = 0;
 326
 327         memset(&local, 0, sizeof(local));
 328         memset(&remote, 0, sizeof(remote));
 329
 330         remote.sin_family = AF_INET;
 331         remote.sin_addr.s_addr = 0xffffffff;
 332         remote.sin_port = htons(EAD_PORT);
 333
 334         local.sin_family = AF_INET;
 335         local.sin_addr.s_addr = INADDR_ANY;
 336         local.sin_port = 0;
 337
 338         while ((ch = getopt(argc, argv, "b:s:h")) != -1) {
 339                 switch(ch) {
 340                 case 's':
 341                         inet_aton(optarg, &serverip);
 342                         break;
 343                 case 'b':
 344                         inet_aton(optarg, &remote.sin_addr);
 345                         break;
 346                 case 'h':
 347                         return usage(prog);
 348                 }
 349         }
 350         argv += optind;
 351         argc -= optind;
 352
 353         switch(argc) {
 354         case 3:
 355                 command = argv[2];
 356                 /* fall through */
 357         case 2:
 358                 username = argv[1];
 359                 st = strchr(username, ':');
 360                 if (st) {
 361                         *st = 0;
 362                         st++;
 363                         strncpy(password, st, sizeof(password));
 364                         password[sizeof(password) - 1] = 0;
 365                         /* hide command line password */
 366                         memset(st, 0, strlen(st));
 367                 }
 368                 /* fall through */
 369         case 1:
 370                 nid = strtoul(argv[0], &st, 16);
 371                 if (st && st[0] != 0)
 372                         return usage(prog);
 373                 /* fall through */
 374         case 0:
 375                 break;
 376         default:
 377                 return usage(prog);
 378         }
 379
 380         msg->nid = htons(nid);
 381         s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 382         if (s < 0) {
 383                 perror("socket");
 384                 return -1;
 385         }
 386
 387         setsockopt(s, SOL_SOCKET, SO_BROADCAST, &val, sizeof(val));
 388
 389         if (bind(s, (struct sockaddr *)&local, sizeof(local)) < 0) {
 390                 perror("bind");
 391                 return -1;
 392         }
 393         sockflags = fcntl(s, F_GETFL);
 394
 395         if (!send_ping()) {
 396                 fprintf(stderr, "No devices found\n");
 397                 return 1;
 398         }
 399
 400         if (nid == 0xffff)
 401                 return 0;
 402
 403         if (!username || !password[0])
 404                 return 0;
 405
 406         if (!send_username()) {
 407                 fprintf(stderr, "Device did not accept user name\n");
 408                 return 1;
 409         }
 410         timeout = EAD_TIMEOUT_LONG;
 411         if (!get_prime()) {
 412                 fprintf(stderr, "Failed to get user password info\n");
 413                 return 1;
 414         }
 415         if (!send_a()) {
 416                 fprintf(stderr, "Failed to send local authentication data\n");
 417                 return 1;
 418         }
 419         if (!send_auth()) {
 420                 fprintf(stderr, "Authentication failed\n");
 421                 return 1;
 422         }
 423         if (!command) {
 424                 fprintf(stderr, "Authentication succesful\n");
 425                 return 0;
 426         }
 427         if (!send_command(command)) {
 428                 fprintf(stderr, "Command failed\n");
 429                 return 1;
 430         }
 431
 432         return 0;
 433 }