demos/tunala/tunala.c

   1 #if defined(NO_BUFFER) || defined(NO_IP) || defined(NO_OPENSSL)
   2 #error "Badness, NO_BUFFER, NO_IP or NO_OPENSSL is defined, turn them *off*"
   3 #endif
   4
   5 /* Include our bits'n'pieces */
   6 #include "tunala.h"
   7
   8
   9 /********************************************/
  10 /* Our local types that specify our "world" */
  11 /********************************************/
  12
  13 /* These represent running "tunnels". Eg. if you wanted to do SSL in a
  14  * "message-passing" scanario, the "int" file-descriptors might be replaced by
  15  * thread or process IDs, and the "select" code might be replaced by message
  16  * handling code. Whatever. */
  17 typedef struct _tunala_item_t {
  18         /* The underlying SSL state machine. This is a data-only processing unit
  19          * and we communicate with it by talking to its four "buffers". */
  20         state_machine_t sm;
  21         /* The file-descriptors for the "dirty" (encrypted) side of the SSL
  22          * setup. In actuality, this is typically a socket and both values are
  23          * identical. */
  24         int dirty_read, dirty_send;
  25         /* The file-descriptors for the "clean" (unencrypted) side of the SSL
  26          * setup. These could be stdin/stdout, a socket (both values the same),
  27          * or whatever you like. */
  28         int clean_read, clean_send;
  29 } tunala_item_t;
  30
  31 /* This structure is used as the data for running the main loop. Namely, in a
  32  * network format such as this, it is stuff for select() - but as pointed out,
  33  * when moving the real-world to somewhere else, this might be replaced by
  34  * something entirely different. It's basically the stuff that controls when
  35  * it's time to do some "work". */
  36 typedef struct _select_sets_t {
  37         int max; /* As required as the first argument to select() */
  38         fd_set reads, sends, excepts; /* As passed to select() */
  39 } select_sets_t;
  40 typedef struct _tunala_selector_t {
  41         select_sets_t last_selected; /* Results of the last select() */
  42         select_sets_t next_select; /* What we'll next select on */
  43 } tunala_selector_t;
  44
  45 /* This structure is *everything*. We do it to avoid the use of globals so that,
  46  * for example, it would be easier to shift things around between async-IO,
  47  * thread-based, or multi-fork()ed (or combinations thereof). */
  48 typedef struct _tunala_world_t {
  49         /* The file-descriptor we "listen" on for new connections */
  50         int listen_fd;
  51         /* The array of tunnels */
  52         tunala_item_t *tunnels;
  53         /* the number of tunnels in use and allocated, respectively */
  54         unsigned int tunnels_used, tunnels_size;
  55         /* Our outside "loop" context stuff */
  56         tunala_selector_t selector;
  57         /* Our SSL_CTX, which is configured as the SSL client or server and has
  58          * the various cert-settings and callbacks configured. */
  59         SSL_CTX *ssl_ctx;
  60         /* Simple flag with complex logic :-) Indicates whether we're an SSL
  61          * server or an SSL client. */
  62         int server_mode;
  63 } tunala_world_t;
  64
  65 /*****************************/
  66 /* Internal static functions */
  67 /*****************************/
  68
  69 static SSL_CTX *initialise_ssl_ctx(int server_mode, const char *engine_id,
  70                 const char *CAfile, const char *cert, const char *key,
  71                 const char *dcert, const char *dkey, const char *cipher_list,
  72                 const char *dh_file, const char *dh_special, int ctx_options,
  73                 int out_state, int out_verify, int verify_mode,
  74                 unsigned int verify_depth);
  75 static void selector_init(tunala_selector_t *selector);
  76 static void selector_add_listener(tunala_selector_t *selector, int fd);
  77 static void selector_add_tunala(tunala_selector_t *selector, tunala_item_t *t);
  78 static int selector_select(tunala_selector_t *selector);
  79 /* This returns -1 for error, 0 for no new connections, or 1 for success, in
  80  * which case *newfd is populated. */
  81 static int selector_get_listener(tunala_selector_t *selector, int fd, int *newfd);
  82 static int tunala_world_new_item(tunala_world_t *world, int fd,
  83                 const char *ip, unsigned short port, int flipped);
  84 static void tunala_world_del_item(tunala_world_t *world, unsigned int idx);
  85 static int tunala_item_io(tunala_selector_t *selector, tunala_item_t *item);
  86
  87 /*********************************************/
  88 /* MAIN FUNCTION (and its utility functions) */
  89 /*********************************************/
  90
  91 static const char *def_proxyhost = "127.0.0.1:443";
  92 static const char *def_listenhost = "127.0.0.1:8080";
  93 static int def_max_tunnels = 50;
  94 static const char *def_cacert = NULL;
  95 static const char *def_cert = NULL;
  96 static const char *def_key = NULL;
  97 static const char *def_dcert = NULL;
  98 static const char *def_dkey = NULL;
  99 static const char *def_engine_id = NULL;
 100 static int def_server_mode = 0;
 101 static int def_flipped = 0;
 102 static const char *def_cipher_list = NULL;
 103 static const char *def_dh_file = NULL;
 104 static const char *def_dh_special = NULL;
 105 static int def_ctx_options = 0;
 106 static int def_verify_mode = 0;
 107 static unsigned int def_verify_depth = 10;
 108 static int def_out_state = 0;
 109 static unsigned int def_out_verify = 0;
 110 static int def_out_totals = 0;
 111
 112 static const char *helpstring =
 113 "\n'Tunala' (A tunneler with a New Zealand accent)\n"
 114 "Usage: tunala [options], where options are from;\n"
 115 " -listen [host:]<port>  (default = 127.0.0.1:8080)\n"
 116 " -proxy <host>:<port>   (default = 127.0.0.1:443)\n"
 117 " -maxtunnels <num>      (default = 50)\n"
 118 " -cacert <path|NULL>    (default = NULL)\n"
 119 " -cert <path|NULL>      (default = NULL)\n"
 120 " -key <path|NULL>       (default = whatever '-cert' is)\n"
 121 " -dcert <path|NULL>     (usually for DSA, default = NULL)\n"
 122 " -dkey <path|NULL>      (usually for DSA, default = whatever '-dcert' is)\n"
 123 " -engine <id|NULL>      (default = NULL)\n"
 124 " -server <0|1>          (default = 0, ie. an SSL client)\n"
 125 " -flipped <0|1>         (makes SSL servers be network clients, and vice versa)\n"
 126 " -cipher <list>         (specifies cipher list to use)\n"
 127 " -dh_file <path>        (a PEM file containing DH parameters to use)\n"
 128 " -dh_special <NULL|generate|standard> (see below: def=NULL)\n"
 129 " -no_ssl2               (disable SSLv2)\n"
 130 " -no_ssl3               (disable SSLv3)\n"
 131 " -no_tls1               (disable TLSv1)\n"
 132 " -v_peer                (verify the peer certificate)\n"
 133 " -v_strict              (do not continue if peer doesn't authenticate)\n"
 134 " -v_once                (no verification in renegotiates)\n"
 135 " -v_depth <num>         (limit certificate chain depth, default = 10)\n"
 136 " -out_state             (prints SSL handshake states)\n"
 137 " -out_verify <0|1|2|3>  (prints certificate verification states: def=1)\n"
 138 " -out_totals            (prints out byte-totals when a tunnel closes)\n"
 139 " -<h|help|?>            (displays this help screen)\n"
 140 "Notes:\n"
 141 "(1) It is recommended to specify a cert+key when operating as an SSL server.\n"
 142 "    If you only specify '-cert', the same file must contain a matching\n"
 143 "    private key.\n"
 144 "(2) Either dh_file or dh_special can be used to specify where DH parameters\n"
 145 "    will be obtained from (or '-dh_special NULL' for the default choice) but\n"
 146 "    you cannot specify both. For dh_special, 'generate' will create new DH\n"
 147 "    parameters on startup, and 'standard' will use embedded parameters\n"
 148 "    instead.\n"
 149 "(3) Normally an ssl client connects to an ssl server - so that an 'ssl client\n"
 150 "    tunala' listens for 'clean' client connections and proxies ssl, and an\n"
 151 "    'ssl server tunala' listens for ssl connections and proxies 'clean'. With\n"
 152 "    '-flipped 1', this behaviour is reversed so that an 'ssl server tunala'\n"
 153 "    listens for clean client connections and proxies ssl (but participating\n"
 154 "    as an ssl *server* in the SSL/TLS protocol), and an 'ssl client tunala'\n"
 155 "    listens for ssl connections (participating as an ssl *client* in the\n"
 156 "    SSL/TLS protocol) and proxies 'clean' to the end destination. This can\n"
 157 "    be useful for allowing network access to 'servers' where only the server\n"
 158 "    needs to authenticate the client (ie. the other way is not required).\n"
 159 "    Even with client and server authentication, this 'technique' mitigates\n"
 160 "    some DoS (denial-of-service) potential as it will be the network client\n"
 161 "    having to perform the first private key operation rather than the other\n"
 162 "    way round.\n"
 163 "(4) The 'technique' used by setting '-flipped 1' is probably compatible with\n"
 164 "    absolutely nothing except another complimentary instance of 'tunala'\n"
 165 "    running with '-flipped 1'. :-)\n";
 166
 167 /* Default DH parameters for use with "-dh_special standard" ... stolen striaght
 168  * from s_server. */
 169 static unsigned char dh512_p[]={
 170         0xDA,0x58,0x3C,0x16,0xD9,0x85,0x22,0x89,0xD0,0xE4,0xAF,0x75,
 171         0x6F,0x4C,0xCA,0x92,0xDD,0x4B,0xE5,0x33,0xB8,0x04,0xFB,0x0F,
 172         0xED,0x94,0xEF,0x9C,0x8A,0x44,0x03,0xED,0x57,0x46,0x50,0xD3,
 173         0x69,0x99,0xDB,0x29,0xD7,0x76,0x27,0x6B,0xA2,0xD3,0xD4,0x12,
 174         0xE2,0x18,0xF4,0xDD,0x1E,0x08,0x4C,0xF6,0xD8,0x00,0x3E,0x7C,
 175         0x47,0x74,0xE8,0x33,
 176         };
 177 static unsigned char dh512_g[]={
 178         0x02,
 179         };
 180
 181 /* And the function that parses the above "standard" parameters, again, straight
 182  * out of s_server. */
 183 static DH *get_dh512(void)
 184         {
 185         DH *dh=NULL;
 186
 187         if ((dh=DH_new()) == NULL) return(NULL);
 188         dh->p=BN_bin2bn(dh512_p,sizeof(dh512_p),NULL);
 189         dh->g=BN_bin2bn(dh512_g,sizeof(dh512_g),NULL);
 190         if ((dh->p == NULL) || (dh->g == NULL))
 191                 return(NULL);
 192         return(dh);
 193         }
 194
 195 /* Various help/error messages used by main() */
 196 static int usage(const char *errstr, int isunknownarg)
 197 {
 198         if(isunknownarg)
 199                 fprintf(stderr, "Error: unknown argument '%s'\n", errstr);
 200         else
 201                 fprintf(stderr, "Error: %s\n", errstr);
 202         fprintf(stderr, "%s\n", helpstring);
 203         return 1;
 204 }
 205
 206 static int err_str0(const char *str0)
 207 {
 208         fprintf(stderr, "%s\n", str0);
 209         return 1;
 210 }
 211
 212 static int err_str1(const char *fmt, const char *str1)
 213 {
 214         fprintf(stderr, fmt, str1);
 215         fprintf(stderr, "\n");
 216         return 1;
 217 }
 218
 219 static int parse_max_tunnels(const char *s, unsigned int *maxtunnels)
 220 {
 221         unsigned long l;
 222         if(!int_strtoul(s, &l) || (l < 1) || (l > 1024)) {
 223                 fprintf(stderr, "Error, '%s' is an invalid value for "
 224                                 "maxtunnels\n", s);
 225                 return 0;
 226         }
 227         *maxtunnels = (unsigned int)l;
 228         return 1;
 229 }
 230
 231 static int parse_server_mode(const char *s, int *servermode)
 232 {
 233         unsigned long l;
 234         if(!int_strtoul(s, &l) || (l > 1)) {
 235                 fprintf(stderr, "Error, '%s' is an invalid value for the "
 236                                 "server mode\n", s);
 237                 return 0;
 238         }
 239         *servermode = (int)l;
 240         return 1;
 241 }
 242
 243 static int parse_dh_special(const char *s, const char **dh_special)
 244 {
 245         if((strcmp(s, "NULL") == 0) || (strcmp(s, "generate") == 0) ||
 246                         (strcmp(s, "standard") == 0)) {
 247                 *dh_special = s;
 248                 return 1;
 249         }
 250         fprintf(stderr, "Error, '%s' is an invalid value for 'dh_special'\n", s);
 251         return 0;
 252 }
 253
 254 static int parse_verify_level(const char *s, unsigned int *verify_level)
 255 {
 256         unsigned long l;
 257         if(!int_strtoul(s, &l) || (l > 3)) {
 258                 fprintf(stderr, "Error, '%s' is an invalid value for "
 259                                 "out_verify\n", s);
 260                 return 0;
 261         }
 262         *verify_level = (unsigned int)l;
 263         return 1;
 264 }
 265
 266 static int parse_verify_depth(const char *s, unsigned int *verify_depth)
 267 {
 268         unsigned long l;
 269         if(!int_strtoul(s, &l) || (l < 1) || (l > 50)) {
 270                 fprintf(stderr, "Error, '%s' is an invalid value for "
 271                                 "verify_depth\n", s);
 272                 return 0;
 273         }
 274         *verify_depth = (unsigned int)l;
 275         return 1;
 276 }
 277
 278 /* Some fprintf format strings used when tunnels close */
 279 static const char *io_stats_client_dirty =
 280 "    SSL (network) traffic to/from server; %8lu bytes in, %8lu bytes out\n";
 281 static const char *io_stats_client_clean =
 282 "    tunnelled data to/from server;        %8lu bytes in, %8lu bytes out\n";
 283 static const char *io_stats_server_dirty =
 284 "    SSL (network) traffic to/from client; %8lu bytes in, %8lu bytes out\n";
 285 static const char *io_stats_server_clean =
 286 "    tunnelled data to/from client;        %8lu bytes in, %8lu bytes out\n";
 287
 288 int main(int argc, char *argv[])
 289 {
 290         unsigned int loop;
 291         int newfd;
 292         tunala_world_t world;
 293         tunala_item_t *t_item;
 294         const char *proxy_ip;
 295         unsigned short proxy_port;
 296         /* Overridables */
 297         const char *proxyhost = def_proxyhost;
 298         const char *listenhost = def_listenhost;
 299         unsigned int max_tunnels = def_max_tunnels;
 300         const char *cacert = def_cacert;
 301         const char *cert = def_cert;
 302         const char *key = def_key;
 303         const char *dcert = def_dcert;
 304         const char *dkey = def_dkey;
 305         const char *engine_id = def_engine_id;
 306         int server_mode = def_server_mode;
 307         int flipped = def_flipped;
 308         const char *cipher_list = def_cipher_list;
 309         const char *dh_file = def_dh_file;
 310         const char *dh_special = def_dh_special;
 311         int ctx_options = def_ctx_options;
 312         int verify_mode = def_verify_mode;
 313         unsigned int verify_depth = def_verify_depth;
 314         int out_state = def_out_state;
 315         unsigned int out_verify = def_out_verify;
 316         int out_totals = def_out_totals;
 317
 318 /* Parse command-line arguments */
 319 next_arg:
 320         argc--; argv++;
 321         if(argc > 0) {
 322                 if(strcmp(*argv, "-listen") == 0) {
 323                         if(argc < 2)
 324                                 return usage("-listen requires an argument", 0);
 325                         argc--; argv++;
 326                         listenhost = *argv;
 327                         goto next_arg;
 328                 } else if(strcmp(*argv, "-proxy") == 0) {
 329                         if(argc < 2)
 330                                 return usage("-proxy requires an argument", 0);
 331                         argc--; argv++;
 332                         proxyhost = *argv;
 333                         goto next_arg;
 334                 } else if(strcmp(*argv, "-maxtunnels") == 0) {
 335                         if(argc < 2)
 336                                 return usage("-maxtunnels requires an argument", 0);
 337                         argc--; argv++;
 338                         if(!parse_max_tunnels(*argv, &max_tunnels))
 339                                 return 1;
 340                         goto next_arg;
 341                 } else if(strcmp(*argv, "-cacert") == 0) {
 342                         if(argc < 2)
 343                                 return usage("-cacert requires an argument", 0);
 344                         argc--; argv++;
 345                         if(strcmp(*argv, "NULL") == 0)
 346                                 cacert = NULL;
 347                         else
 348                                 cacert = *argv;
 349                         goto next_arg;
 350                 } else if(strcmp(*argv, "-cert") == 0) {
 351                         if(argc < 2)
 352                                 return usage("-cert requires an argument", 0);
 353                         argc--; argv++;
 354                         if(strcmp(*argv, "NULL") == 0)
 355                                 cert = NULL;
 356                         else
 357                                 cert = *argv;
 358                         goto next_arg;
 359                 } else if(strcmp(*argv, "-key") == 0) {
 360                         if(argc < 2)
 361                                 return usage("-key requires an argument", 0);
 362                         argc--; argv++;
 363                         if(strcmp(*argv, "NULL") == 0)
 364                                 key = NULL;
 365                         else
 366                                 key = *argv;
 367                         goto next_arg;
 368                 } else if(strcmp(*argv, "-dcert") == 0) {
 369                         if(argc < 2)
 370                                 return usage("-dcert requires an argument", 0);
 371                         argc--; argv++;
 372                         if(strcmp(*argv, "NULL") == 0)
 373                                 dcert = NULL;
 374                         else
 375                                 dcert = *argv;
 376                         goto next_arg;
 377                 } else if(strcmp(*argv, "-dkey") == 0) {
 378                         if(argc < 2)
 379                                 return usage("-dkey requires an argument", 0);
 380                         argc--; argv++;
 381                         if(strcmp(*argv, "NULL") == 0)
 382                                 dkey = NULL;
 383                         else
 384                                 dkey = *argv;
 385                         goto next_arg;
 386                 } else if(strcmp(*argv, "-engine") == 0) {
 387                         if(argc < 2)
 388                                 return usage("-engine requires an argument", 0);
 389                         argc--; argv++;
 390                         engine_id = *argv;
 391                         goto next_arg;
 392                 } else if(strcmp(*argv, "-server") == 0) {
 393                         if(argc < 2)
 394                                 return usage("-server requires an argument", 0);
 395                         argc--; argv++;
 396                         if(!parse_server_mode(*argv, &server_mode))
 397                                 return 1;
 398                         goto next_arg;
 399                 } else if(strcmp(*argv, "-flipped") == 0) {
 400                         if(argc < 2)
 401                                 return usage("-flipped requires an argument", 0);
 402                         argc--; argv++;
 403                         if(!parse_server_mode(*argv, &flipped))
 404                                 return 1;
 405                         goto next_arg;
 406                 } else if(strcmp(*argv, "-cipher") == 0) {
 407                         if(argc < 2)
 408                                 return usage("-cipher requires an argument", 0);
 409                         argc--; argv++;
 410                         cipher_list = *argv;
 411                         goto next_arg;
 412                 } else if(strcmp(*argv, "-dh_file") == 0) {
 413                         if(argc < 2)
 414                                 return usage("-dh_file requires an argument", 0);
 415                         if(dh_special)
 416                                 return usage("cannot mix -dh_file with "
 417                                                 "-dh_special", 0);
 418                         argc--; argv++;
 419                         dh_file = *argv;
 420                         goto next_arg;
 421                 } else if(strcmp(*argv, "-dh_special") == 0) {
 422                         if(argc < 2)
 423                                 return usage("-dh_special requires an argument", 0);
 424                         if(dh_file)
 425                                 return usage("cannot mix -dh_file with "
 426                                                 "-dh_special", 0);
 427                         argc--; argv++;
 428                         if(!parse_dh_special(*argv, &dh_special))
 429                                 return 1;
 430                         goto next_arg;
 431                 } else if(strcmp(*argv, "-no_ssl2") == 0) {
 432                         ctx_options |= SSL_OP_NO_SSLv2;
 433                         goto next_arg;
 434                 } else if(strcmp(*argv, "-no_ssl3") == 0) {
 435                         ctx_options |= SSL_OP_NO_SSLv3;
 436                         goto next_arg;
 437                 } else if(strcmp(*argv, "-no_tls1") == 0) {
 438                         ctx_options |= SSL_OP_NO_TLSv1;
 439                         goto next_arg;
 440                 } else if(strcmp(*argv, "-v_peer") == 0) {
 441                         verify_mode |= SSL_VERIFY_PEER;
 442                         goto next_arg;
 443                 } else if(strcmp(*argv, "-v_strict") == 0) {
 444                         verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
 445                         goto next_arg;
 446                 } else if(strcmp(*argv, "-v_once") == 0) {
 447                         verify_mode |= SSL_VERIFY_CLIENT_ONCE;
 448                         goto next_arg;
 449                 } else if(strcmp(*argv, "-v_depth") == 0) {
 450                         if(argc < 2)
 451                                 return usage("-v_depth requires an argument", 0);
 452                         argc--; argv++;
 453                         if(!parse_verify_depth(*argv, &verify_depth))
 454                                 return 1;
 455                         goto next_arg;
 456                 } else if(strcmp(*argv, "-out_state") == 0) {
 457                         out_state = 1;
 458                         goto next_arg;
 459                 } else if(strcmp(*argv, "-out_verify") == 0) {
 460                         if(argc < 2)
 461                                 return usage("-out_verify requires an argument", 0);
 462                         argc--; argv++;
 463                         if(!parse_verify_level(*argv, &out_verify))
 464                                 return 1;
 465                         goto next_arg;
 466                 } else if(strcmp(*argv, "-out_totals") == 0) {
 467                         out_totals = 1;
 468                         goto next_arg;
 469                 } else if((strcmp(*argv, "-h") == 0) ||
 470                                 (strcmp(*argv, "-help") == 0) ||
 471                                 (strcmp(*argv, "-?") == 0)) {
 472                         fprintf(stderr, "%s\n", helpstring);
 473                         return 0;
 474                 } else
 475                         return usage(*argv, 1);
 476         }
 477
 478         /* Initialise network stuff */
 479         if(!ip_initialise())
 480                 return err_str0("ip_initialise failed");
 481         err_str0("ip_initialise succeeded");
 482         /* Create the SSL_CTX */
 483         if((world.ssl_ctx = initialise_ssl_ctx(server_mode, engine_id,
 484                         cacert, cert, key, dcert, dkey, cipher_list, dh_file,
 485                         dh_special, ctx_options, out_state, out_verify,
 486                         verify_mode, verify_depth)) == NULL)
 487                 return err_str1("initialise_ssl_ctx(engine_id=%s) failed",
 488                         (engine_id == NULL) ? "NULL" : engine_id);
 489         err_str1("initialise_ssl_ctx(engine_id=%s) succeeded",
 490                         (engine_id == NULL) ? "NULL" : engine_id);
 491         /* Create the listener */
 492         if((world.listen_fd = ip_create_listener(listenhost)) == -1)
 493                 return err_str1("ip_create_listener(%s) failed", listenhost);
 494         err_str1("ip_create_listener(%s) succeeded", listenhost);
 495         if(!ip_parse_address(proxyhost, &proxy_ip, &proxy_port, 0))
 496                 return err_str1("ip_parse_address(%s) failed", proxyhost);
 497         err_str1("ip_parse_address(%s) succeeded", proxyhost);
 498         fprintf(stderr, "Info - proxying to %d.%d.%d.%d:%d\n",
 499                         (int)proxy_ip[0], (int)proxy_ip[1],
 500                         (int)proxy_ip[2], (int)proxy_ip[3], (int)proxy_port);
 501         fprintf(stderr, "Info - set maxtunnels to %d\n", (int)max_tunnels);
 502         fprintf(stderr, "Info - set to operate as an SSL %s\n",
 503                         (server_mode ? "server" : "client"));
 504         /* Initialise the rest of the stuff */
 505         world.tunnels_used = world.tunnels_size = 0;
 506         world.tunnels = NULL;
 507         world.server_mode = server_mode;
 508         selector_init(&world.selector);
 509
 510 /* We're ready to loop */
 511 main_loop:
 512         /* Should we listen for *new* tunnels? */
 513         if(world.tunnels_used < max_tunnels)
 514                 selector_add_listener(&world.selector, world.listen_fd);
 515         /* We should add in our existing tunnels */
 516         for(loop = 0; loop < world.tunnels_used; loop++)
 517                 selector_add_tunala(&world.selector, world.tunnels + loop);
 518         /* Now do the select */
 519         switch(selector_select(&world.selector)) {
 520         case -1:
 521                 fprintf(stderr, "selector_select returned a badness error.\n");
 522                 goto shouldnt_happen;
 523         case 0:
 524                 fprintf(stderr, "Warn, selector_select returned 0 - signal?""?\n");
 525                 goto main_loop;
 526         default:
 527                 break;
 528         }
 529         /* Accept new connection if we should and can */
 530         if((world.tunnels_used < max_tunnels) && (selector_get_listener(
 531                                         &world.selector, world.listen_fd,
 532                                         &newfd) == 1)) {
 533                 /* We have a new connection */
 534                 if(!tunala_world_new_item(&world, newfd, proxy_ip,
 535                                                 proxy_port, flipped))
 536                         fprintf(stderr, "tunala_world_new_item failed\n");
 537                 else
 538                         fprintf(stderr, "Info, new tunnel opened, now up to "
 539                                         "%d\n", world.tunnels_used);
 540         }
 541         /* Give each tunnel its moment, note the while loop is because it makes
 542          * the logic easier than with "for" to deal with an array that may shift
 543          * because of deletes. */
 544         loop = 0;
 545         t_item = world.tunnels;
 546         while(loop < world.tunnels_used) {
 547                 if(!tunala_item_io(&world.selector, t_item)) {
 548                         /* We're closing whether for reasons of an error or a
 549                          * natural close. Don't increment loop or t_item because
 550                          * the next item is moving to us! */
 551                         if(!out_totals)
 552                                 goto skip_totals;
 553                         fprintf(stderr, "Tunnel closing, traffic stats follow\n");
 554                         /* Display the encrypted (over the network) stats */
 555                         fprintf(stderr, (server_mode ? io_stats_server_dirty :
 556                                                 io_stats_client_dirty),
 557                                 buffer_total_in(state_machine_get_buffer(
 558                                                 &t_item->sm,SM_DIRTY_IN)),
 559                                 buffer_total_out(state_machine_get_buffer(
 560                                                 &t_item->sm,SM_DIRTY_OUT)));
 561                         /* Display the local (tunnelled) stats. NB: Data we
 562                          * *receive* is data sent *out* of the state_machine on
 563                          * its 'clean' side. Hence the apparent back-to-front
 564                          * OUT/IN mixup here :-) */
 565                         fprintf(stderr, (server_mode ? io_stats_server_clean :
 566                                                 io_stats_client_clean),
 567                                 buffer_total_out(state_machine_get_buffer(
 568                                                 &t_item->sm,SM_CLEAN_OUT)),
 569                                 buffer_total_in(state_machine_get_buffer(
 570                                                 &t_item->sm,SM_CLEAN_IN)));
 571 skip_totals:
 572                         tunala_world_del_item(&world, loop);
 573                         fprintf(stderr, "Info, tunnel closed, down to %d\n",
 574                                         world.tunnels_used);
 575                 }
 576                 else {
 577                         /* Move to the next item */
 578                         loop++;
 579                         t_item++;
 580                 }
 581         }
 582         goto main_loop;
 583         /* Should never get here */
 584 shouldnt_happen:
 585         abort();
 586         return 1;
 587 }
 588
 589 /****************/
 590 /* OpenSSL bits */
 591 /****************/
 592
 593 static int ctx_set_cert(SSL_CTX *ctx, const char *cert, const char *key)
 594 {
 595         FILE *fp = NULL;
 596         X509 *x509 = NULL;
 597         EVP_PKEY *pkey = NULL;
 598         int toret = 0; /* Assume an error */
 599
 600         /* cert */
 601         if(cert) {
 602                 if((fp = fopen(cert, "r")) == NULL) {
 603                         fprintf(stderr, "Error opening cert file '%s'\n", cert);
 604                         goto err;
 605                 }
 606                 if(!PEM_read_X509(fp, &x509, NULL, NULL)) {
 607                         fprintf(stderr, "Error reading PEM cert from '%s'\n",
 608                                         cert);
 609                         goto err;
 610                 }
 611                 if(!SSL_CTX_use_certificate(ctx, x509)) {
 612                         fprintf(stderr, "Error, cert in '%s' can not be used\n",
 613                                         cert);
 614                         goto err;
 615                 }
 616                 /* Clear the FILE* for reuse in the "key" code */
 617                 fclose(fp);
 618                 fp = NULL;
 619                 fprintf(stderr, "Info, operating with cert in '%s'\n", cert);
 620                 /* If a cert was given without matching key, we assume the same
 621                  * file contains the required key. */
 622                 if(!key)
 623                         key = cert;
 624         } else {
 625                 if(key)
 626                         fprintf(stderr, "Error, can't specify a key without a "
 627                                         "corresponding certificate\n");
 628                 else
 629                         fprintf(stderr, "Error, ctx_set_cert called with "
 630                                         "NULLs!\n");
 631                 goto err;
 632         }
 633         /* key */
 634         if(key) {
 635                 if((fp = fopen(key, "r")) == NULL) {
 636                         fprintf(stderr, "Error opening key file '%s'\n", key);
 637                         goto err;
 638                 }
 639                 if(!PEM_read_PrivateKey(fp, &pkey, NULL, NULL)) {
 640                         fprintf(stderr, "Error reading PEM key from '%s'\n",
 641                                         key);
 642                         goto err;
 643                 }
 644                 if(!SSL_CTX_use_PrivateKey(ctx, pkey)) {
 645                         fprintf(stderr, "Error, key in '%s' can not be used\n",
 646                                         key);
 647                         goto err;
 648                 }
 649                 fprintf(stderr, "Info, operating with key in '%s'\n", key);
 650         } else
 651                 fprintf(stderr, "Info, operating without a cert or key\n");
 652         /* Success */
 653         toret = 1; err:
 654         if(x509)
 655                 X509_free(x509);
 656         if(pkey)
 657                 EVP_PKEY_free(pkey);
 658         if(fp)
 659                 fclose(fp);
 660         return toret;
 661 }
 662
 663 static int ctx_set_dh(SSL_CTX *ctx, const char *dh_file, const char *dh_special)
 664 {
 665         DH *dh = NULL;
 666         FILE *fp = NULL;
 667
 668         if(dh_special) {
 669                 if(strcmp(dh_special, "NULL") == 0)
 670                         return 1;
 671                 if(strcmp(dh_special, "standard") == 0) {
 672                         if((dh = get_dh512()) == NULL) {
 673                                 fprintf(stderr, "Error, can't parse 'standard'"
 674                                                 " DH parameters\n");
 675                                 return 0;
 676                         }
 677                         fprintf(stderr, "Info, using 'standard' DH parameters\n");
 678                         goto do_it;
 679                 }
 680                 if(strcmp(dh_special, "generate") != 0)
 681                         /* This shouldn't happen - screening values is handled
 682                          * in main(). */
 683                         abort();
 684                 fprintf(stderr, "Info, generating DH parameters ... ");
 685                 fflush(stderr);
 686                 if((dh = DH_generate_parameters(512, DH_GENERATOR_5,
 687                                         NULL, NULL)) == NULL) {
 688                         fprintf(stderr, "error!\n");
 689                         return 0;
 690                 }
 691                 fprintf(stderr, "complete\n");
 692                 goto do_it;
 693         }
 694         /* So, we're loading dh_file */
 695         if((fp = fopen(dh_file, "r")) == NULL) {
 696                 fprintf(stderr, "Error, couldn't open '%s' for DH parameters\n",
 697                                 dh_file);
 698                 return 0;
 699         }
 700         dh = PEM_read_DHparams(fp, NULL, NULL, NULL);
 701         fclose(fp);
 702         if(dh == NULL) {
 703                 fprintf(stderr, "Error, could not parse DH parameters from '%s'\n",
 704                                 dh_file);
 705                 return 0;
 706         }
 707         fprintf(stderr, "Info, using DH parameters from file '%s'\n", dh_file);
 708 do_it:
 709         SSL_CTX_set_tmp_dh(ctx, dh);
 710         DH_free(dh);
 711         return 1;
 712 }
 713
 714 static SSL_CTX *initialise_ssl_ctx(int server_mode, const char *engine_id,
 715                 const char *CAfile, const char *cert, const char *key,
 716                 const char *dcert, const char *dkey, const char *cipher_list,
 717                 const char *dh_file, const char *dh_special, int ctx_options,
 718                 int out_state, int out_verify, int verify_mode,
 719                 unsigned int verify_depth)
 720 {
 721         SSL_CTX *ctx, *ret = NULL;
 722         SSL_METHOD *meth;
 723         ENGINE *e = NULL;
 724
 725         OpenSSL_add_ssl_algorithms();
 726         SSL_load_error_strings();
 727
 728         meth = (server_mode ? SSLv23_server_method() : SSLv23_client_method());
 729         if(meth == NULL)
 730                 goto err;
 731         if(engine_id) {
 732                 ENGINE_load_builtin_engines();
 733                 if((e = ENGINE_by_id(engine_id)) == NULL) {
 734                         fprintf(stderr, "Error obtaining '%s' engine, openssl "
 735                                         "errors follow\n", engine_id);
 736                         goto err;
 737                 }
 738                 if(!ENGINE_set_default(e, ENGINE_METHOD_ALL)) {
 739                         fprintf(stderr, "Error assigning '%s' engine, openssl "
 740                                         "errors follow\n", engine_id);
 741                         goto err;
 742                 }
 743                 ENGINE_free(e);
 744         }
 745         if((ctx = SSL_CTX_new(meth)) == NULL)
 746                 goto err;
 747         /* cacert */
 748         if(CAfile) {
 749                 if(!X509_STORE_load_locations(SSL_CTX_get_cert_store(ctx),
 750                                         CAfile, NULL)) {
 751                         fprintf(stderr, "Error loading CA cert(s) in '%s'\n",
 752                                         CAfile);
 753                         goto err;
 754                 }
 755                 fprintf(stderr, "Info, operating with CA cert(s) in '%s'\n",
 756                                 CAfile);
 757         } else
 758                 fprintf(stderr, "Info, operating without a CA cert(-list)\n");
 759         if(!SSL_CTX_set_default_verify_paths(ctx)) {
 760                 fprintf(stderr, "Error setting default verify paths\n");
 761                 goto err;
 762         }
 763
 764         /* cert and key */
 765         if((cert || key) && !ctx_set_cert(ctx, cert, key))
 766                 goto err;
 767         /* dcert and dkey */
 768         if((dcert || dkey) && !ctx_set_cert(ctx, dcert, dkey))
 769                 goto err;
 770
 771         /* cipher_list */
 772         if(cipher_list) {
 773                 if(!SSL_CTX_set_cipher_list(ctx, cipher_list)) {
 774                         fprintf(stderr, "Error setting cipher list '%s'\n",
 775                                         cipher_list);
 776                         goto err;
 777                 }
 778                 fprintf(stderr, "Info, set cipher list '%s'\n", cipher_list);
 779         } else
 780                 fprintf(stderr, "Info, operating with default cipher list\n");
 781
 782         /* dh_file & dh_special */
 783         if((dh_file || dh_special) && !ctx_set_dh(ctx, dh_file, dh_special))
 784                 goto err;
 785
 786         /* ctx_options */
 787         SSL_CTX_set_options(ctx, ctx_options);
 788
 789         /* out_state (output of SSL handshake states to screen). */
 790         if(out_state)
 791                 cb_ssl_info_set_output(stderr);
 792
 793         /* out_verify */
 794         if(out_verify > 0) {
 795                 cb_ssl_verify_set_output(stderr);
 796                 cb_ssl_verify_set_level(out_verify);
 797         }
 798
 799         /* verify_depth */
 800         cb_ssl_verify_set_depth(verify_depth);
 801
 802         /* Success! (includes setting verify_mode) */
 803         SSL_CTX_set_info_callback(ctx, cb_ssl_info);
 804         SSL_CTX_set_verify(ctx, verify_mode, cb_ssl_verify);
 805         ret = ctx;
 806 err:
 807         if(!ret) {
 808                 ERR_print_errors_fp(stderr);
 809                 if(ctx)
 810                         SSL_CTX_free(ctx);
 811         }
 812         return ret;
 813 }
 814
 815 /*****************/
 816 /* Selector bits */
 817 /*****************/
 818
 819 static void selector_sets_init(select_sets_t *s)
 820 {
 821         s->max = 0;
 822         FD_ZERO(&s->reads);
 823         FD_ZERO(&s->sends);
 824         FD_ZERO(&s->excepts);
 825 }
 826 static void selector_init(tunala_selector_t *selector)
 827 {
 828         selector_sets_init(&selector->last_selected);
 829         selector_sets_init(&selector->next_select);
 830 }
 831
 832 #define SEL_EXCEPTS 0x00
 833 #define SEL_READS   0x01
 834 #define SEL_SENDS   0x02
 835 static void selector_add_raw_fd(tunala_selector_t *s, int fd, int flags)
 836 {
 837         FD_SET(fd, &s->next_select.excepts);
 838         if(flags & SEL_READS)
 839                 FD_SET(fd, &s->next_select.reads);
 840         if(flags & SEL_SENDS)
 841                 FD_SET(fd, &s->next_select.sends);
 842         /* Adjust "max" */
 843         if(s->next_select.max < (fd + 1))
 844                 s->next_select.max = fd + 1;
 845 }
 846
 847 static void selector_add_listener(tunala_selector_t *selector, int fd)
 848 {
 849         selector_add_raw_fd(selector, fd, SEL_READS);
 850 }
 851
 852 static void selector_add_tunala(tunala_selector_t *s, tunala_item_t *t)
 853 {
 854         /* Set clean read if sm.clean_in is not full */
 855         if(t->clean_read != -1) {
 856                 selector_add_raw_fd(s, t->clean_read,
 857                         (buffer_full(state_machine_get_buffer(&t->sm,
 858                                 SM_CLEAN_IN)) ? SEL_EXCEPTS : SEL_READS));
 859         }
 860         /* Set clean send if sm.clean_out is not empty */
 861         if(t->clean_send != -1) {
 862                 selector_add_raw_fd(s, t->clean_send,
 863                         (buffer_empty(state_machine_get_buffer(&t->sm,
 864                                 SM_CLEAN_OUT)) ? SEL_EXCEPTS : SEL_SENDS));
 865         }
 866         /* Set dirty read if sm.dirty_in is not full */
 867         if(t->dirty_read != -1) {
 868                 selector_add_raw_fd(s, t->dirty_read,
 869                         (buffer_full(state_machine_get_buffer(&t->sm,
 870                                 SM_DIRTY_IN)) ? SEL_EXCEPTS : SEL_READS));
 871         }
 872         /* Set dirty send if sm.dirty_out is not empty */
 873         if(t->dirty_send != -1) {
 874                 selector_add_raw_fd(s, t->dirty_send,
 875                         (buffer_empty(state_machine_get_buffer(&t->sm,
 876                                 SM_DIRTY_OUT)) ? SEL_EXCEPTS : SEL_SENDS));
 877         }
 878 }
 879
 880 static int selector_select(tunala_selector_t *selector)
 881 {
 882         memcpy(&selector->last_selected, &selector->next_select,
 883                         sizeof(select_sets_t));
 884         selector_sets_init(&selector->next_select);
 885         return select(selector->last_selected.max,
 886                         &selector->last_selected.reads,
 887                         &selector->last_selected.sends,
 888                         &selector->last_selected.excepts, NULL);
 889 }
 890
 891 /* This returns -1 for error, 0 for no new connections, or 1 for success, in
 892  * which case *newfd is populated. */
 893 static int selector_get_listener(tunala_selector_t *selector, int fd, int *newfd)
 894 {
 895         if(FD_ISSET(fd, &selector->last_selected.excepts))
 896                 return -1;
 897         if(!FD_ISSET(fd, &selector->last_selected.reads))
 898                 return 0;
 899         if((*newfd = ip_accept_connection(fd)) == -1)
 900                 return -1;
 901         return 1;
 902 }
 903
 904 /************************/
 905 /* "Tunala" world stuff */
 906 /************************/
 907
 908 static int tunala_world_make_room(tunala_world_t *world)
 909 {
 910         unsigned int newsize;
 911         tunala_item_t *newarray;
 912
 913         if(world->tunnels_used < world->tunnels_size)
 914                 return 1;
 915         newsize = (world->tunnels_size == 0 ? 16 :
 916                         ((world->tunnels_size * 3) / 2));
 917         if((newarray = malloc(newsize * sizeof(tunala_item_t))) == NULL)
 918                 return 0;
 919         memset(newarray, 0, newsize * sizeof(tunala_item_t));
 920         if(world->tunnels_used > 0)
 921                 memcpy(newarray, world->tunnels,
 922                         world->tunnels_used * sizeof(tunala_item_t));
 923         if(world->tunnels_size > 0)
 924                 free(world->tunnels);
 925         /* migrate */
 926         world->tunnels = newarray;
 927         world->tunnels_size = newsize;
 928         return 1;
 929 }
 930
 931 static int tunala_world_new_item(tunala_world_t *world, int fd,
 932                 const char *ip, unsigned short port, int flipped)
 933 {
 934         tunala_item_t *item;
 935         int newfd;
 936         SSL *new_ssl = NULL;
 937
 938         if(!tunala_world_make_room(world))
 939                 return 0;
 940         if((new_ssl = SSL_new(world->ssl_ctx)) == NULL) {
 941                 fprintf(stderr, "Error creating new SSL\n");
 942                 ERR_print_errors_fp(stderr);
 943                 return 0;
 944         }
 945         item = world->tunnels + (world->tunnels_used++);
 946         state_machine_init(&item->sm);
 947         item->clean_read = item->clean_send =
 948                 item->dirty_read = item->dirty_send = -1;
 949         if((newfd = ip_create_connection_split(ip, port)) == -1)
 950                 goto err;
 951         /* Which way round? If we're a server, "fd" is the dirty side and the
 952          * connection we open is the clean one. For a client, it's the other way
 953          * around. Unless, of course, we're "flipped" in which case everything
 954          * gets reversed. :-) */
 955         if((world->server_mode && !flipped) ||
 956                         (!world->server_mode && flipped)) {
 957                 item->dirty_read = item->dirty_send = fd;
 958                 item->clean_read = item->clean_send = newfd;
 959         } else {
 960                 item->clean_read = item->clean_send = fd;
 961                 item->dirty_read = item->dirty_send = newfd;
 962         }
 963         /* We use the SSL's "app_data" to indicate a call-back induced "kill" */
 964         SSL_set_app_data(new_ssl, NULL);
 965         if(!state_machine_set_SSL(&item->sm, new_ssl, world->server_mode))
 966                 goto err;
 967         return 1;
 968 err:
 969         tunala_world_del_item(world, world->tunnels_used - 1);
 970         return 0;
 971
 972 }
 973
 974 static void tunala_world_del_item(tunala_world_t *world, unsigned int idx)
 975 {
 976         tunala_item_t *item = world->tunnels + idx;
 977         if(item->clean_read != -1)
 978                 close(item->clean_read);
 979         if(item->clean_send != item->clean_read)
 980                 close(item->clean_send);
 981         item->clean_read = item->clean_send = -1;
 982         if(item->dirty_read != -1)
 983                 close(item->dirty_read);
 984         if(item->dirty_send != item->dirty_read)
 985                 close(item->dirty_send);
 986         item->dirty_read = item->dirty_send = -1;
 987         state_machine_close(&item->sm);
 988         /* OK, now we fix the item array */
 989         if(idx + 1 < world->tunnels_used)
 990                 /* We need to scroll entries to the left */
 991                 memmove(world->tunnels + idx,
 992                                 world->tunnels + (idx + 1),
 993                                 (world->tunnels_used - (idx + 1)) *
 994                                         sizeof(tunala_item_t));
 995         world->tunnels_used--;
 996 }
 997
 998 static int tunala_item_io(tunala_selector_t *selector, tunala_item_t *item)
 999 {
1000         int c_r, c_s, d_r, d_s; /* Four boolean flags */
1001
1002         /* Take ourselves out of the gene-pool if there was an except */
1003         if((item->clean_read != -1) && FD_ISSET(item->clean_read,
1004                                 &selector->last_selected.excepts))
1005                 return 0;
1006         if((item->clean_send != -1) && FD_ISSET(item->clean_send,
1007                                 &selector->last_selected.excepts))
1008                 return 0;
1009         if((item->dirty_read != -1) && FD_ISSET(item->dirty_read,
1010                                 &selector->last_selected.excepts))
1011                 return 0;
1012         if((item->dirty_send != -1) && FD_ISSET(item->dirty_send,
1013                                 &selector->last_selected.excepts))
1014                 return 0;
1015         /* Grab our 4 IO flags */
1016         c_r = c_s = d_r = d_s = 0;
1017         if(item->clean_read != -1)
1018                 c_r = FD_ISSET(item->clean_read, &selector->last_selected.reads);
1019         if(item->clean_send != -1)
1020                 c_s = FD_ISSET(item->clean_send, &selector->last_selected.sends);
1021         if(item->dirty_read != -1)
1022                 d_r = FD_ISSET(item->dirty_read, &selector->last_selected.reads);
1023         if(item->dirty_send != -1)
1024                 d_s = FD_ISSET(item->dirty_send, &selector->last_selected.sends);
1025         /* If no IO has happened for us, skip needless data looping */
1026         if(!c_r && !c_s && !d_r && !d_s)
1027                 return 1;
1028         if(c_r)
1029                 c_r = (buffer_from_fd(state_machine_get_buffer(&item->sm,
1030                                 SM_CLEAN_IN), item->clean_read) <= 0);
1031         if(c_s)
1032                 c_s = (buffer_to_fd(state_machine_get_buffer(&item->sm,
1033                                 SM_CLEAN_OUT), item->clean_send) <= 0);
1034         if(d_r)
1035                 d_r = (buffer_from_fd(state_machine_get_buffer(&item->sm,
1036                                 SM_DIRTY_IN), item->dirty_read) <= 0);
1037         if(d_s)
1038                 d_s = (buffer_to_fd(state_machine_get_buffer(&item->sm,
1039                                 SM_DIRTY_OUT), item->dirty_send) <= 0);
1040         /* If any of the flags is non-zero, that means they need closing */
1041         if(c_r) {
1042                 close(item->clean_read);
1043                 if(item->clean_send == item->clean_read)
1044                         item->clean_send = -1;
1045                 item->clean_read = -1;
1046         }
1047         if(c_s && (item->clean_send != -1)) {
1048                 close(item->clean_send);
1049                 if(item->clean_send == item->clean_read)
1050                         item->clean_read = -1;
1051                 item->clean_send = -1;
1052         }
1053         if(d_r) {
1054                 close(item->dirty_read);
1055                 if(item->dirty_send == item->dirty_read)
1056                         item->dirty_send = -1;
1057                 item->dirty_read = -1;
1058         }
1059         if(d_s && (item->dirty_send != -1)) {
1060                 close(item->dirty_send);
1061                 if(item->dirty_send == item->dirty_read)
1062                         item->dirty_read = -1;
1063                 item->dirty_send = -1;
1064         }
1065         /* This function name is attributed to the term donated by David
1066          * Schwartz on openssl-dev, message-ID:
1067          * <NCBBLIEPOCNJOAEKBEAKEEDGLIAA.davids@webmaster.com>. :-) */
1068         if(!state_machine_churn(&item->sm))
1069                 /* If the SSL closes, it will also zero-out the _in buffers
1070                  * and will in future process just outgoing data. As and
1071                  * when the outgoing data has gone, it will return zero
1072                  * here to tell us to bail out. */
1073                 return 0;
1074         /* Otherwise, we return zero if both sides are dead. */
1075         if(((item->clean_read == -1) || (item->clean_send == -1)) &&
1076                         ((item->dirty_read == -1) || (item->dirty_send == -1)))
1077                 return 0;
1078         /* If only one side closed, notify the SSL of this so it can take
1079          * appropriate action. */
1080         if((item->clean_read == -1) || (item->clean_send == -1)) {
1081                 if(!state_machine_close_clean(&item->sm))
1082                         return 0;
1083         }
1084         if((item->dirty_read == -1) || (item->dirty_send == -1)) {
1085                 if(!state_machine_close_dirty(&item->sm))
1086                         return 0;
1087         }
1088         return 1;
1089 }
1090