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 unsigned 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         char *temp;
 223         l = strtoul(s, &temp, 10);
 224         if((temp == s) || (*temp != '\0') || (l < 1) || (l > 1024)) {
 225                 fprintf(stderr, "Error, '%s' is an invalid value for "
 226                                 "maxtunnels\n", s);
 227                 return 0;
 228         }
 229         *maxtunnels = (unsigned int)l;
 230         return 1;
 231 }
 232
 233 static int parse_server_mode(const char *s, int *servermode)
 234 {
 235         unsigned long l;
 236         char *temp;
 237         l = strtoul(s, &temp, 10);
 238         if((temp == s) || (*temp != '\0') || (l > 1)) {
 239                 fprintf(stderr, "Error, '%s' is an invalid value for the "
 240                                 "server mode\n", s);
 241                 return 0;
 242         }
 243         *servermode = (int)l;
 244         return 1;
 245 }
 246
 247 static int parse_dh_special(const char *s, const char **dh_special)
 248 {
 249         if((strcmp(s, "NULL") == 0) || (strcmp(s, "generate") == 0) ||
 250                         (strcmp(s, "standard") == 0)) {
 251                 *dh_special = s;
 252                 return 1;
 253         }
 254         fprintf(stderr, "Error, '%s' is an invalid value for 'dh_special'\n", s);
 255         return 0;
 256 }
 257
 258 static int parse_verify_level(const char *s, unsigned int *verify_level)
 259 {
 260         unsigned long l;
 261         char *temp;
 262         l = strtoul(s, &temp, 10);
 263         if((temp == s) || (*temp != '\0') || (l > 3)) {
 264                 fprintf(stderr, "Error, '%s' is an invalid value for "
 265                                 "out_verify\n", s);
 266                 return 0;
 267         }
 268         *verify_level = (unsigned int)l;
 269         return 1;
 270 }
 271
 272 static int parse_verify_depth(const char *s, unsigned int *verify_depth)
 273 {
 274         unsigned long l;
 275         char *temp;
 276         l = strtoul(s, &temp, 10);
 277         if((temp == s) || (*temp != '\0') || (l < 1) || (l > 50)) {
 278                 fprintf(stderr, "Error, '%s' is an invalid value for "
 279                                 "verify_depth\n", s);
 280                 return 0;
 281         }
 282         *verify_depth = (unsigned int)l;
 283         return 1;
 284 }
 285
 286 /* Some fprintf format strings used when tunnels close */
 287 static const char *io_stats_client_dirty =
 288 "    SSL (network) traffic to/from server; %8lu bytes in, %8lu bytes out\n";
 289 static const char *io_stats_client_clean =
 290 "    tunnelled data to/from server;        %8lu bytes in, %8lu bytes out\n";
 291 static const char *io_stats_server_dirty =
 292 "    SSL (network) traffic to/from client; %8lu bytes in, %8lu bytes out\n";
 293 static const char *io_stats_server_clean =
 294 "    tunnelled data to/from client;        %8lu bytes in, %8lu bytes out\n";
 295
 296 int main(int argc, char *argv[])
 297 {
 298         unsigned int loop;
 299         int newfd;
 300         tunala_world_t world;
 301         tunala_item_t *t_item;
 302         unsigned char *proxy_ip;
 303         unsigned short proxy_port;
 304         /* Overridables */
 305         const char *proxyhost = def_proxyhost;
 306         const char *listenhost = def_listenhost;
 307         unsigned int max_tunnels = def_max_tunnels;
 308         const char *cacert = def_cacert;
 309         const char *cert = def_cert;
 310         const char *key = def_key;
 311         const char *dcert = def_dcert;
 312         const char *dkey = def_dkey;
 313         const char *engine_id = def_engine_id;
 314         int server_mode = def_server_mode;
 315         int flipped = def_flipped;
 316         const char *cipher_list = def_cipher_list;
 317         const char *dh_file = def_dh_file;
 318         const char *dh_special = def_dh_special;
 319         int ctx_options = def_ctx_options;
 320         int verify_mode = def_verify_mode;
 321         unsigned int verify_depth = def_verify_depth;
 322         int out_state = def_out_state;
 323         unsigned int out_verify = def_out_verify;
 324         int out_totals = def_out_totals;
 325
 326 /* Parse command-line arguments */
 327 next_arg:
 328         argc--; argv++;
 329         if(argc > 0) {
 330                 if(strcmp(*argv, "-listen") == 0) {
 331                         if(argc < 2)
 332                                 return usage("-listen requires an argument", 0);
 333                         argc--; argv++;
 334                         listenhost = *argv;
 335                         goto next_arg;
 336                 } else if(strcmp(*argv, "-proxy") == 0) {
 337                         if(argc < 2)
 338                                 return usage("-proxy requires an argument", 0);
 339                         argc--; argv++;
 340                         proxyhost = *argv;
 341                         goto next_arg;
 342                 } else if(strcmp(*argv, "-maxtunnels") == 0) {
 343                         if(argc < 2)
 344                                 return usage("-maxtunnels requires an argument", 0);
 345                         argc--; argv++;
 346                         if(!parse_max_tunnels(*argv, &max_tunnels))
 347                                 return 1;
 348                         goto next_arg;
 349                 } else if(strcmp(*argv, "-cacert") == 0) {
 350                         if(argc < 2)
 351                                 return usage("-cacert requires an argument", 0);
 352                         argc--; argv++;
 353                         if(strcmp(*argv, "NULL") == 0)
 354                                 cacert = NULL;
 355                         else
 356                                 cacert = *argv;
 357                         goto next_arg;
 358                 } else if(strcmp(*argv, "-cert") == 0) {
 359                         if(argc < 2)
 360                                 return usage("-cert requires an argument", 0);
 361                         argc--; argv++;
 362                         if(strcmp(*argv, "NULL") == 0)
 363                                 cert = NULL;
 364                         else
 365                                 cert = *argv;
 366                         goto next_arg;
 367                 } else if(strcmp(*argv, "-key") == 0) {
 368                         if(argc < 2)
 369                                 return usage("-key requires an argument", 0);
 370                         argc--; argv++;
 371                         if(strcmp(*argv, "NULL") == 0)
 372                                 key = NULL;
 373                         else
 374                                 key = *argv;
 375                         goto next_arg;
 376                 } else if(strcmp(*argv, "-dcert") == 0) {
 377                         if(argc < 2)
 378                                 return usage("-dcert requires an argument", 0);
 379                         argc--; argv++;
 380                         if(strcmp(*argv, "NULL") == 0)
 381                                 dcert = NULL;
 382                         else
 383                                 dcert = *argv;
 384                         goto next_arg;
 385                 } else if(strcmp(*argv, "-dkey") == 0) {
 386                         if(argc < 2)
 387                                 return usage("-dkey requires an argument", 0);
 388                         argc--; argv++;
 389                         if(strcmp(*argv, "NULL") == 0)
 390                                 dkey = NULL;
 391                         else
 392                                 dkey = *argv;
 393                         goto next_arg;
 394                 } else if(strcmp(*argv, "-engine") == 0) {
 395                         if(argc < 2)
 396                                 return usage("-engine requires an argument", 0);
 397                         argc--; argv++;
 398                         engine_id = *argv;
 399                         goto next_arg;
 400                 } else if(strcmp(*argv, "-server") == 0) {
 401                         if(argc < 2)
 402                                 return usage("-server requires an argument", 0);
 403                         argc--; argv++;
 404                         if(!parse_server_mode(*argv, &server_mode))
 405                                 return 1;
 406                         goto next_arg;
 407                 } else if(strcmp(*argv, "-flipped") == 0) {
 408                         if(argc < 2)
 409                                 return usage("-flipped requires an argument", 0);
 410                         argc--; argv++;
 411                         if(!parse_server_mode(*argv, &flipped))
 412                                 return 1;
 413                         goto next_arg;
 414                 } else if(strcmp(*argv, "-cipher") == 0) {
 415                         if(argc < 2)
 416                                 return usage("-cipher requires an argument", 0);
 417                         argc--; argv++;
 418                         cipher_list = *argv;
 419                         goto next_arg;
 420                 } else if(strcmp(*argv, "-dh_file") == 0) {
 421                         if(argc < 2)
 422                                 return usage("-dh_file requires an argument", 0);
 423                         if(dh_special)
 424                                 return usage("cannot mix -dh_file with "
 425                                                 "-dh_special", 0);
 426                         argc--; argv++;
 427                         dh_file = *argv;
 428                         goto next_arg;
 429                 } else if(strcmp(*argv, "-dh_special") == 0) {
 430                         if(argc < 2)
 431                                 return usage("-dh_special requires an argument", 0);
 432                         if(dh_file)
 433                                 return usage("cannot mix -dh_file with "
 434                                                 "-dh_special", 0);
 435                         argc--; argv++;
 436                         if(!parse_dh_special(*argv, &dh_special))
 437                                 return 1;
 438                         goto next_arg;
 439                 } else if(strcmp(*argv, "-no_ssl2") == 0) {
 440                         ctx_options |= SSL_OP_NO_SSLv2;
 441                         goto next_arg;
 442                 } else if(strcmp(*argv, "-no_ssl3") == 0) {
 443                         ctx_options |= SSL_OP_NO_SSLv3;
 444                         goto next_arg;
 445                 } else if(strcmp(*argv, "-no_tls1") == 0) {
 446                         ctx_options |= SSL_OP_NO_TLSv1;
 447                         goto next_arg;
 448                 } else if(strcmp(*argv, "-v_peer") == 0) {
 449                         verify_mode |= SSL_VERIFY_PEER;
 450                         goto next_arg;
 451                 } else if(strcmp(*argv, "-v_strict") == 0) {
 452                         verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
 453                         goto next_arg;
 454                 } else if(strcmp(*argv, "-v_once") == 0) {
 455                         verify_mode |= SSL_VERIFY_CLIENT_ONCE;
 456                         goto next_arg;
 457                 } else if(strcmp(*argv, "-v_depth") == 0) {
 458                         if(argc < 2)
 459                                 return usage("-v_depth requires an argument", 0);
 460                         argc--; argv++;
 461                         if(!parse_verify_depth(*argv, &verify_depth))
 462                                 return 1;
 463                         goto next_arg;
 464                 } else if(strcmp(*argv, "-out_state") == 0) {
 465                         out_state = 1;
 466                         goto next_arg;
 467                 } else if(strcmp(*argv, "-out_verify") == 0) {
 468                         if(argc < 2)
 469                                 return usage("-out_verify requires an argument", 0);
 470                         argc--; argv++;
 471                         if(!parse_verify_level(*argv, &out_verify))
 472                                 return 1;
 473                         goto next_arg;
 474                 } else if(strcmp(*argv, "-out_totals") == 0) {
 475                         out_totals = 1;
 476                         goto next_arg;
 477                 } else if((strcmp(*argv, "-h") == 0) ||
 478                                 (strcmp(*argv, "-help") == 0) ||
 479                                 (strcmp(*argv, "-?") == 0)) {
 480                         fprintf(stderr, "%s\n", helpstring);
 481                         return 0;
 482                 } else
 483                         return usage(*argv, 1);
 484         }
 485
 486         /* Initialise network stuff */
 487         if(!ip_initialise())
 488                 return err_str0("ip_initialise failed");
 489         err_str0("ip_initialise succeeded");
 490         /* Create the SSL_CTX */
 491         if((world.ssl_ctx = initialise_ssl_ctx(server_mode, engine_id,
 492                         cacert, cert, key, dcert, dkey, cipher_list, dh_file,
 493                         dh_special, ctx_options, out_state, out_verify,
 494                         verify_mode, verify_depth)) == NULL)
 495                 return err_str1("initialise_ssl_ctx(engine_id=%s) failed",
 496                         (engine_id == NULL) ? "NULL" : engine_id);
 497         err_str1("initialise_ssl_ctx(engine_id=%s) succeeded",
 498                         (engine_id == NULL) ? "NULL" : engine_id);
 499         /* Create the listener */
 500         if((world.listen_fd = ip_create_listener(listenhost)) == -1)
 501                 return err_str1("ip_create_listener(%s) failed", listenhost);
 502         err_str1("ip_create_listener(%s) succeeded", listenhost);
 503         if(!ip_parse_address(proxyhost, &proxy_ip, &proxy_port, 0))
 504                 return err_str1("ip_parse_address(%s) failed", proxyhost);
 505         err_str1("ip_parse_address(%s) succeeded", proxyhost);
 506         fprintf(stderr, "Info - proxying to %d.%d.%d.%d:%d\n",
 507                         (int)proxy_ip[0], (int)proxy_ip[1],
 508                         (int)proxy_ip[2], (int)proxy_ip[3], (int)proxy_port);
 509         fprintf(stderr, "Info - set maxtunnels to %d\n", (int)max_tunnels);
 510         fprintf(stderr, "Info - set to operate as an SSL %s\n",
 511                         (server_mode ? "server" : "client"));
 512         /* Initialise the rest of the stuff */
 513         world.tunnels_used = world.tunnels_size = 0;
 514         world.tunnels = NULL;
 515         world.server_mode = server_mode;
 516         selector_init(&world.selector);
 517
 518 /* We're ready to loop */
 519 main_loop:
 520         /* Should we listen for *new* tunnels? */
 521         if(world.tunnels_used < max_tunnels)
 522                 selector_add_listener(&world.selector, world.listen_fd);
 523         /* We should add in our existing tunnels */
 524         for(loop = 0; loop < world.tunnels_used; loop++)
 525                 selector_add_tunala(&world.selector, world.tunnels + loop);
 526         /* Now do the select */
 527         switch(selector_select(&world.selector)) {
 528         case -1:
 529                 fprintf(stderr, "selector_select returned a badness error.\n");
 530                 abort();
 531         case 0:
 532                 fprintf(stderr, "Warn, selector_select returned 0 - signal??\n");
 533                 goto main_loop;
 534         default:
 535                 break;
 536         }
 537         /* Accept new connection if we should and can */
 538         if((world.tunnels_used < max_tunnels) && (selector_get_listener(
 539                                         &world.selector, world.listen_fd,
 540                                         &newfd) == 1)) {
 541                 /* We have a new connection */
 542                 if(!tunala_world_new_item(&world, newfd, proxy_ip,
 543                                                 proxy_port, flipped))
 544                         fprintf(stderr, "tunala_world_new_item failed\n");
 545                 else
 546                         fprintf(stderr, "Info, new tunnel opened, now up to "
 547                                         "%d\n", world.tunnels_used);
 548         }
 549         /* Give each tunnel its moment, note the while loop is because it makes
 550          * the logic easier than with "for" to deal with an array that may shift
 551          * because of deletes. */
 552         loop = 0;
 553         t_item = world.tunnels;
 554         while(loop < world.tunnels_used) {
 555                 if(!tunala_item_io(&world.selector, t_item)) {
 556                         /* We're closing whether for reasons of an error or a
 557                          * natural close. Don't increment loop or t_item because
 558                          * the next item is moving to us! */
 559                         if(!out_totals)
 560                                 goto skip_totals;
 561                         fprintf(stderr, "Tunnel closing, traffic stats follow\n");
 562                         /* Display the encrypted (over the network) stats */
 563                         fprintf(stderr, (server_mode ? io_stats_server_dirty :
 564                                                 io_stats_client_dirty),
 565                                 buffer_total_in(state_machine_get_buffer(
 566                                                 &t_item->sm,SM_DIRTY_IN)),
 567                                 buffer_total_out(state_machine_get_buffer(
 568                                                 &t_item->sm,SM_DIRTY_OUT)));
 569                         /* Display the local (tunnelled) stats. NB: Data we
 570                          * *receive* is data sent *out* of the state_machine on
 571                          * its 'clean' side. Hence the apparent back-to-front
 572                          * OUT/IN mixup here :-) */
 573                         fprintf(stderr, (server_mode ? io_stats_server_clean :
 574                                                 io_stats_client_clean),
 575                                 buffer_total_out(state_machine_get_buffer(
 576                                                 &t_item->sm,SM_CLEAN_OUT)),
 577                                 buffer_total_in(state_machine_get_buffer(
 578                                                 &t_item->sm,SM_CLEAN_IN)));
 579 skip_totals:
 580                         tunala_world_del_item(&world, loop);
 581                         fprintf(stderr, "Info, tunnel closed, down to %d\n",
 582                                         world.tunnels_used);
 583                 }
 584                 else {
 585                         /* Move to the next item */
 586                         loop++;
 587                         t_item++;
 588                 }
 589         }
 590         goto main_loop;
 591         /* Should never get here */
 592         abort();
 593         return 1;
 594 }
 595
 596 /****************/
 597 /* OpenSSL bits */
 598 /****************/
 599
 600 static int ctx_set_cert(SSL_CTX *ctx, const char *cert, const char *key)
 601 {
 602         FILE *fp = NULL;
 603         X509 *x509 = NULL;
 604         EVP_PKEY *pkey = NULL;
 605         int toret = 0; /* Assume an error */
 606
 607         /* cert */
 608         if(cert) {
 609                 if((fp = fopen(cert, "r")) == NULL) {
 610                         fprintf(stderr, "Error opening cert file '%s'\n", cert);
 611                         goto err;
 612                 }
 613                 if(!PEM_read_X509(fp, &x509, NULL, NULL)) {
 614                         fprintf(stderr, "Error reading PEM cert from '%s'\n",
 615                                         cert);
 616                         goto err;
 617                 }
 618                 if(!SSL_CTX_use_certificate(ctx, x509)) {
 619                         fprintf(stderr, "Error, cert in '%s' can not be used\n",
 620                                         cert);
 621                         goto err;
 622                 }
 623                 /* Clear the FILE* for reuse in the "key" code */
 624                 fclose(fp);
 625                 fp = NULL;
 626                 fprintf(stderr, "Info, operating with cert in '%s'\n", cert);
 627                 /* If a cert was given without matching key, we assume the same
 628                  * file contains the required key. */
 629                 if(!key)
 630                         key = cert;
 631         } else {
 632                 if(key)
 633                         fprintf(stderr, "Error, can't specify a key without a "
 634                                         "corresponding certificate\n");
 635                 else
 636                         fprintf(stderr, "Error, ctx_set_cert called with "
 637                                         "NULLs!\n");
 638                 goto err;
 639         }
 640         /* key */
 641         if(key) {
 642                 if((fp = fopen(key, "r")) == NULL) {
 643                         fprintf(stderr, "Error opening key file '%s'\n", key);
 644                         goto err;
 645                 }
 646                 if(!PEM_read_PrivateKey(fp, &pkey, NULL, NULL)) {
 647                         fprintf(stderr, "Error reading PEM key from '%s'\n",
 648                                         key);
 649                         goto err;
 650                 }
 651                 if(!SSL_CTX_use_PrivateKey(ctx, pkey)) {
 652                         fprintf(stderr, "Error, key in '%s' can not be used\n",
 653                                         key);
 654                         goto err;
 655                 }
 656                 fprintf(stderr, "Info, operating with key in '%s'\n", key);
 657         } else
 658                 fprintf(stderr, "Info, operating without a cert or key\n");
 659         /* Success */
 660         toret = 1; err:
 661         if(x509)
 662                 X509_free(x509);
 663         if(pkey)
 664                 EVP_PKEY_free(pkey);
 665         if(fp)
 666                 fclose(fp);
 667         return toret;
 668 }
 669
 670 static int ctx_set_dh(SSL_CTX *ctx, const char *dh_file, const char *dh_special)
 671 {
 672         DH *dh = NULL;
 673         FILE *fp = NULL;
 674
 675         if(dh_special) {
 676                 if(strcmp(dh_special, "NULL") == 0)
 677                         return 1;
 678                 if(strcmp(dh_special, "standard") == 0) {
 679                         if((dh = get_dh512()) == NULL) {
 680                                 fprintf(stderr, "Error, can't parse 'standard'"
 681                                                 " DH parameters\n");
 682                                 return 0;
 683                         }
 684                         fprintf(stderr, "Info, using 'standard' DH parameters\n");
 685                         goto do_it;
 686                 }
 687                 if(strcmp(dh_special, "generate") != 0)
 688                         /* This shouldn't happen - screening values is handled
 689                          * in main(). */
 690                         abort();
 691                 fprintf(stderr, "Info, generating DH parameters ... ");
 692                 fflush(stderr);
 693                 if((dh = DH_generate_parameters(512, DH_GENERATOR_5,
 694                                         NULL, NULL)) == NULL) {
 695                         fprintf(stderr, "error!\n");
 696                         return 0;
 697                 }
 698                 fprintf(stderr, "complete\n");
 699                 goto do_it;
 700         }
 701         /* So, we're loading dh_file */
 702         if((fp = fopen(dh_file, "r")) == NULL) {
 703                 fprintf(stderr, "Error, couldn't open '%s' for DH parameters\n",
 704                                 dh_file);
 705                 return 0;
 706         }
 707         dh = PEM_read_DHparams(fp, NULL, NULL, NULL);
 708         fclose(fp);
 709         if(dh == NULL) {
 710                 fprintf(stderr, "Error, could not parse DH parameters from '%s'\n",
 711                                 dh_file);
 712                 return 0;
 713         }
 714         fprintf(stderr, "Info, using DH parameters from file '%s'\n", dh_file);
 715 do_it:
 716         SSL_CTX_set_tmp_dh(ctx, dh);
 717         DH_free(dh);
 718         return 1;
 719 }
 720
 721 static SSL_CTX *initialise_ssl_ctx(int server_mode, const char *engine_id,
 722                 const char *CAfile, const char *cert, const char *key,
 723                 const char *dcert, const char *dkey, const char *cipher_list,
 724                 const char *dh_file, const char *dh_special, int ctx_options,
 725                 int out_state, int out_verify, int verify_mode,
 726                 unsigned int verify_depth)
 727 {
 728         SSL_CTX *ctx, *ret = NULL;
 729         SSL_METHOD *meth;
 730         ENGINE *e = NULL;
 731
 732         OpenSSL_add_ssl_algorithms();
 733         SSL_load_error_strings();
 734
 735         meth = (server_mode ? SSLv23_server_method() : SSLv23_client_method());
 736         if(meth == NULL)
 737                 goto err;
 738         if(engine_id) {
 739                 if((e = ENGINE_by_id(engine_id)) == NULL) {
 740                         fprintf(stderr, "Error obtaining '%s' engine, openssl "
 741                                         "errors follow\n", engine_id);
 742                         goto err;
 743                 }
 744                 if(!ENGINE_set_default(e, ENGINE_METHOD_ALL)) {
 745                         fprintf(stderr, "Error assigning '%s' engine, openssl "
 746                                         "errors follow\n", engine_id);
 747                         goto err;
 748                 }
 749                 ENGINE_free(e);
 750         }
 751         if((ctx = SSL_CTX_new(meth)) == NULL)
 752                 goto err;
 753         /* cacert */
 754         if(CAfile) {
 755                 if(!X509_STORE_load_locations(SSL_CTX_get_cert_store(ctx),
 756                                         CAfile, NULL)) {
 757                         fprintf(stderr, "Error loading CA cert(s) in '%s'\n",
 758                                         CAfile);
 759                         goto err;
 760                 }
 761                 fprintf(stderr, "Info, operating with CA cert(s) in '%s'\n",
 762                                 CAfile);
 763         } else
 764                 fprintf(stderr, "Info, operating without a CA cert(-list)\n");
 765         if(!SSL_CTX_set_default_verify_paths(ctx)) {
 766                 fprintf(stderr, "Error setting default verify paths\n");
 767                 goto err;
 768         }
 769
 770         /* cert and key */
 771         if((cert || key) && !ctx_set_cert(ctx, cert, key))
 772                 goto err;
 773         /* dcert and dkey */
 774         if((dcert || dkey) && !ctx_set_cert(ctx, dcert, dkey))
 775                 goto err;
 776
 777         /* cipher_list */
 778         if(cipher_list) {
 779                 if(!SSL_CTX_set_cipher_list(ctx, cipher_list)) {
 780                         fprintf(stderr, "Error setting cipher list '%s'\n",
 781                                         cipher_list);
 782                         goto err;
 783                 }
 784                 fprintf(stderr, "Info, set cipher list '%s'\n", cipher_list);
 785         } else
 786                 fprintf(stderr, "Info, operating with default cipher list\n");
 787
 788         /* dh_file & dh_special */
 789         if((dh_file || dh_special) && !ctx_set_dh(ctx, dh_file, dh_special))
 790                 goto err;
 791
 792         /* ctx_options */
 793         SSL_CTX_set_options(ctx, ctx_options);
 794
 795         /* out_state (output of SSL handshake states to screen). */
 796         if(out_state)
 797                 cb_ssl_info_set_output(stderr);
 798
 799         /* out_verify */
 800         if(out_verify > 0) {
 801                 cb_ssl_verify_set_output(stderr);
 802                 cb_ssl_verify_set_level(out_verify);
 803         }
 804
 805         /* verify_depth */
 806         cb_ssl_verify_set_depth(verify_depth);
 807
 808         /* Success! (includes setting verify_mode) */
 809         SSL_CTX_set_info_callback(ctx, cb_ssl_info);
 810         SSL_CTX_set_verify(ctx, verify_mode, cb_ssl_verify);
 811         ret = ctx;
 812 err:
 813         if(!ret) {
 814                 ERR_print_errors_fp(stderr);
 815                 if(ctx)
 816                         SSL_CTX_free(ctx);
 817         }
 818         return ret;
 819 }
 820
 821 /*****************/
 822 /* Selector bits */
 823 /*****************/
 824
 825 static void selector_sets_init(select_sets_t *s)
 826 {
 827         s->max = 0;
 828         FD_ZERO(&s->reads);
 829         FD_ZERO(&s->sends);
 830         FD_ZERO(&s->excepts);
 831 }
 832 static void selector_init(tunala_selector_t *selector)
 833 {
 834         selector_sets_init(&selector->last_selected);
 835         selector_sets_init(&selector->next_select);
 836 }
 837
 838 #define SEL_EXCEPTS 0x00
 839 #define SEL_READS   0x01
 840 #define SEL_SENDS   0x02
 841 static void selector_add_raw_fd(tunala_selector_t *s, int fd, int flags)
 842 {
 843         FD_SET(fd, &s->next_select.excepts);
 844         if(flags & SEL_READS)
 845                 FD_SET(fd, &s->next_select.reads);
 846         if(flags & SEL_SENDS)
 847                 FD_SET(fd, &s->next_select.sends);
 848         /* Adjust "max" */
 849         if(s->next_select.max < (fd + 1))
 850                 s->next_select.max = fd + 1;
 851 }
 852
 853 static void selector_add_listener(tunala_selector_t *selector, int fd)
 854 {
 855         selector_add_raw_fd(selector, fd, SEL_READS);
 856 }
 857
 858 static void selector_add_tunala(tunala_selector_t *s, tunala_item_t *t)
 859 {
 860         /* Set clean read if sm.clean_in is not full */
 861         if(t->clean_read != -1) {
 862                 selector_add_raw_fd(s, t->clean_read,
 863                         (buffer_full(state_machine_get_buffer(&t->sm,
 864                                 SM_CLEAN_IN)) ? SEL_EXCEPTS : SEL_READS));
 865         }
 866         /* Set clean send if sm.clean_out is not empty */
 867         if(t->clean_send != -1) {
 868                 selector_add_raw_fd(s, t->clean_send,
 869                         (buffer_empty(state_machine_get_buffer(&t->sm,
 870                                 SM_CLEAN_OUT)) ? SEL_EXCEPTS : SEL_SENDS));
 871         }
 872         /* Set dirty read if sm.dirty_in is not full */
 873         if(t->dirty_read != -1) {
 874                 selector_add_raw_fd(s, t->dirty_read,
 875                         (buffer_full(state_machine_get_buffer(&t->sm,
 876                                 SM_DIRTY_IN)) ? SEL_EXCEPTS : SEL_READS));
 877         }
 878         /* Set dirty send if sm.dirty_out is not empty */
 879         if(t->dirty_send != -1) {
 880                 selector_add_raw_fd(s, t->dirty_send,
 881                         (buffer_empty(state_machine_get_buffer(&t->sm,
 882                                 SM_DIRTY_OUT)) ? SEL_EXCEPTS : SEL_SENDS));
 883         }
 884 }
 885
 886 static int selector_select(tunala_selector_t *selector)
 887 {
 888         memcpy(&selector->last_selected, &selector->next_select,
 889                         sizeof(select_sets_t));
 890         selector_sets_init(&selector->next_select);
 891         return select(selector->last_selected.max,
 892                         &selector->last_selected.reads,
 893                         &selector->last_selected.sends,
 894                         &selector->last_selected.excepts, NULL);
 895 }
 896
 897 /* This returns -1 for error, 0 for no new connections, or 1 for success, in
 898  * which case *newfd is populated. */
 899 static int selector_get_listener(tunala_selector_t *selector, int fd, int *newfd)
 900 {
 901         if(FD_ISSET(fd, &selector->last_selected.excepts))
 902                 return -1;
 903         if(!FD_ISSET(fd, &selector->last_selected.reads))
 904                 return 0;
 905         if((*newfd = ip_accept_connection(fd)) == -1)
 906                 return -1;
 907         return 1;
 908 }
 909
 910 /************************/
 911 /* "Tunala" world stuff */
 912 /************************/
 913
 914 static int tunala_world_make_room(tunala_world_t *world)
 915 {
 916         unsigned int newsize;
 917         tunala_item_t *newarray;
 918
 919         if(world->tunnels_used < world->tunnels_size)
 920                 return 1;
 921         newsize = (world->tunnels_size == 0 ? 16 :
 922                         ((world->tunnels_size * 3) / 2));
 923         if((newarray = malloc(newsize * sizeof(tunala_item_t))) == NULL)
 924                 return 0;
 925         memset(newarray, 0, newsize * sizeof(tunala_item_t));
 926         if(world->tunnels_used > 0)
 927                 memcpy(newarray, world->tunnels,
 928                         world->tunnels_used * sizeof(tunala_item_t));
 929         if(world->tunnels_size > 0)
 930                 free(world->tunnels);
 931         /* migrate */
 932         world->tunnels = newarray;
 933         world->tunnels_size = newsize;
 934         return 1;
 935 }
 936
 937 static int tunala_world_new_item(tunala_world_t *world, int fd,
 938                 const unsigned char *ip, unsigned short port, int flipped)
 939 {
 940         tunala_item_t *item;
 941         int newfd;
 942         SSL *new_ssl = NULL;
 943
 944         if(!tunala_world_make_room(world))
 945                 return 0;
 946         if((new_ssl = SSL_new(world->ssl_ctx)) == NULL) {
 947                 fprintf(stderr, "Error creating new SSL\n");
 948                 ERR_print_errors_fp(stderr);
 949                 return 0;
 950         }
 951         item = world->tunnels + (world->tunnels_used++);
 952         state_machine_init(&item->sm);
 953         item->clean_read = item->clean_send =
 954                 item->dirty_read = item->dirty_send = -1;
 955         if((newfd = ip_create_connection_split(ip, port)) == -1)
 956                 goto err;
 957         /* Which way round? If we're a server, "fd" is the dirty side and the
 958          * connection we open is the clean one. For a client, it's the other way
 959          * around. Unless, of course, we're "flipped" in which case everything
 960          * gets reversed. :-) */
 961         if((world->server_mode && !flipped) ||
 962                         (!world->server_mode && flipped)) {
 963                 item->dirty_read = item->dirty_send = fd;
 964                 item->clean_read = item->clean_send = newfd;
 965         } else {
 966                 item->clean_read = item->clean_send = fd;
 967                 item->dirty_read = item->dirty_send = newfd;
 968         }
 969         /* We use the SSL's "app_data" to indicate a call-back induced "kill" */
 970         SSL_set_app_data(new_ssl, NULL);
 971         if(!state_machine_set_SSL(&item->sm, new_ssl, world->server_mode))
 972                 goto err;
 973         return 1;
 974 err:
 975         tunala_world_del_item(world, world->tunnels_used - 1);
 976         return 0;
 977
 978 }
 979
 980 static void tunala_world_del_item(tunala_world_t *world, unsigned int idx)
 981 {
 982         tunala_item_t *item = world->tunnels + idx;
 983         if(item->clean_read != -1)
 984                 close(item->clean_read);
 985         if(item->clean_send != item->clean_read)
 986                 close(item->clean_send);
 987         item->clean_read = item->clean_send = -1;
 988         if(item->dirty_read != -1)
 989                 close(item->dirty_read);
 990         if(item->dirty_send != item->dirty_read)
 991                 close(item->dirty_send);
 992         item->dirty_read = item->dirty_send = -1;
 993         state_machine_close(&item->sm);
 994         /* OK, now we fix the item array */
 995         if(idx + 1 < world->tunnels_used)
 996                 /* We need to scroll entries to the left */
 997                 memmove(world->tunnels + idx,
 998                                 world->tunnels + (idx + 1),
 999                                 (world->tunnels_used - (idx + 1)) *
1000                                         sizeof(tunala_item_t));
1001         world->tunnels_used--;
1002 }
1003
1004 static int tunala_item_io(tunala_selector_t *selector, tunala_item_t *item)
1005 {
1006         int c_r, c_s, d_r, d_s; /* Four boolean flags */
1007
1008         /* Take ourselves out of the gene-pool if there was an except */
1009         if((item->clean_read != -1) && FD_ISSET(item->clean_read,
1010                                 &selector->last_selected.excepts))
1011                 return 0;
1012         if((item->clean_send != -1) && FD_ISSET(item->clean_send,
1013                                 &selector->last_selected.excepts))
1014                 return 0;
1015         if((item->dirty_read != -1) && FD_ISSET(item->dirty_read,
1016                                 &selector->last_selected.excepts))
1017                 return 0;
1018         if((item->dirty_send != -1) && FD_ISSET(item->dirty_send,
1019                                 &selector->last_selected.excepts))
1020                 return 0;
1021         /* Grab our 4 IO flags */
1022         c_r = c_s = d_r = d_s = 0;
1023         if(item->clean_read != -1)
1024                 c_r = FD_ISSET(item->clean_read, &selector->last_selected.reads);
1025         if(item->clean_send != -1)
1026                 c_s = FD_ISSET(item->clean_send, &selector->last_selected.sends);
1027         if(item->dirty_read != -1)
1028                 d_r = FD_ISSET(item->dirty_read, &selector->last_selected.reads);
1029         if(item->dirty_send != -1)
1030                 d_s = FD_ISSET(item->dirty_send, &selector->last_selected.sends);
1031         /* If no IO has happened for us, skip needless data looping */
1032         if(!c_r && !c_s && !d_r && !d_s)
1033                 return 1;
1034         if(c_r)
1035                 c_r = (buffer_from_fd(state_machine_get_buffer(&item->sm,
1036                                 SM_CLEAN_IN), item->clean_read) <= 0);
1037         if(c_s)
1038                 c_s = (buffer_to_fd(state_machine_get_buffer(&item->sm,
1039                                 SM_CLEAN_OUT), item->clean_send) <= 0);
1040         if(d_r)
1041                 d_r = (buffer_from_fd(state_machine_get_buffer(&item->sm,
1042                                 SM_DIRTY_IN), item->dirty_read) <= 0);
1043         if(d_s)
1044                 d_s = (buffer_to_fd(state_machine_get_buffer(&item->sm,
1045                                 SM_DIRTY_OUT), item->dirty_send) <= 0);
1046         /* If any of the flags is non-zero, that means they need closing */
1047         if(c_r) {
1048                 close(item->clean_read);
1049                 if(item->clean_send == item->clean_read)
1050                         item->clean_send = -1;
1051                 item->clean_read = -1;
1052         }
1053         if(c_s && (item->clean_send != -1)) {
1054                 close(item->clean_send);
1055                 if(item->clean_send == item->clean_read)
1056                         item->clean_read = -1;
1057                 item->clean_send = -1;
1058         }
1059         if(d_r) {
1060                 close(item->dirty_read);
1061                 if(item->dirty_send == item->dirty_read)
1062                         item->dirty_send = -1;
1063                 item->dirty_read = -1;
1064         }
1065         if(d_s && (item->dirty_send != -1)) {
1066                 close(item->dirty_send);
1067                 if(item->dirty_send == item->dirty_read)
1068                         item->dirty_read = -1;
1069                 item->dirty_send = -1;
1070         }
1071         /* This function name is attributed to the term donated by David
1072          * Schwartz on openssl-dev, message-ID:
1073          * <NCBBLIEPOCNJOAEKBEAKEEDGLIAA.davids@webmaster.com>. :-) */
1074         if(!state_machine_churn(&item->sm))
1075                 /* If the SSL closes, it will also zero-out the _in buffers
1076                  * and will in future process just outgoing data. As and
1077                  * when the outgoing data has gone, it will return zero
1078                  * here to tell us to bail out. */
1079                 return 0;
1080         /* Otherwise, we return zero if both sides are dead. */
1081         if(((item->clean_read == -1) || (item->clean_send == -1)) &&
1082                         ((item->dirty_read == -1) || (item->dirty_send == -1)))
1083                 return 0;
1084         /* If only one side closed, notify the SSL of this so it can take
1085          * appropriate action. */
1086         if((item->clean_read == -1) || (item->clean_send == -1)) {
1087                 if(!state_machine_close_clean(&item->sm))
1088                         return 0;
1089         }
1090         if((item->dirty_read == -1) || (item->dirty_send == -1)) {
1091                 if(!state_machine_close_dirty(&item->sm))
1092                         return 0;
1093         }
1094         return 1;
1095 }
1096