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 static int def_out_conns = 0;
 112
 113 static const char *helpstring =
 114 "\n'Tunala' (A tunneler with a New Zealand accent)\n"
 115 "Usage: tunala [options], where options are from;\n"
 116 " -listen [host:]<port>  (default = 127.0.0.1:8080)\n"
 117 " -proxy <host>:<port>   (default = 127.0.0.1:443)\n"
 118 " -maxtunnels <num>      (default = 50)\n"
 119 " -cacert <path|NULL>    (default = NULL)\n"
 120 " -cert <path|NULL>      (default = NULL)\n"
 121 " -key <path|NULL>       (default = whatever '-cert' is)\n"
 122 " -dcert <path|NULL>     (usually for DSA, default = NULL)\n"
 123 " -dkey <path|NULL>      (usually for DSA, default = whatever '-dcert' is)\n"
 124 " -engine <id|NULL>      (default = NULL)\n"
 125 " -server <0|1>          (default = 0, ie. an SSL client)\n"
 126 " -flipped <0|1>         (makes SSL servers be network clients, and vice versa)\n"
 127 " -cipher <list>         (specifies cipher list to use)\n"
 128 " -dh_file <path>        (a PEM file containing DH parameters to use)\n"
 129 " -dh_special <NULL|generate|standard> (see below: def=NULL)\n"
 130 " -no_ssl2               (disable SSLv2)\n"
 131 " -no_ssl3               (disable SSLv3)\n"
 132 " -no_tls1               (disable TLSv1)\n"
 133 " -v_peer                (verify the peer certificate)\n"
 134 " -v_strict              (do not continue if peer doesn't authenticate)\n"
 135 " -v_once                (no verification in renegotiates)\n"
 136 " -v_depth <num>         (limit certificate chain depth, default = 10)\n"
 137 " -out_conns             (prints client connections and disconnections)\n"
 138 " -out_state             (prints SSL handshake states)\n"
 139 " -out_verify <0|1|2|3>  (prints certificate verification states: def=1)\n"
 140 " -out_totals            (prints out byte-totals when a tunnel closes)\n"
 141 " -<h|help|?>            (displays this help screen)\n"
 142 "Notes:\n"
 143 "(1) It is recommended to specify a cert+key when operating as an SSL server.\n"
 144 "    If you only specify '-cert', the same file must contain a matching\n"
 145 "    private key.\n"
 146 "(2) Either dh_file or dh_special can be used to specify where DH parameters\n"
 147 "    will be obtained from (or '-dh_special NULL' for the default choice) but\n"
 148 "    you cannot specify both. For dh_special, 'generate' will create new DH\n"
 149 "    parameters on startup, and 'standard' will use embedded parameters\n"
 150 "    instead.\n"
 151 "(3) Normally an ssl client connects to an ssl server - so that an 'ssl client\n"
 152 "    tunala' listens for 'clean' client connections and proxies ssl, and an\n"
 153 "    'ssl server tunala' listens for ssl connections and proxies 'clean'. With\n"
 154 "    '-flipped 1', this behaviour is reversed so that an 'ssl server tunala'\n"
 155 "    listens for clean client connections and proxies ssl (but participating\n"
 156 "    as an ssl *server* in the SSL/TLS protocol), and an 'ssl client tunala'\n"
 157 "    listens for ssl connections (participating as an ssl *client* in the\n"
 158 "    SSL/TLS protocol) and proxies 'clean' to the end destination. This can\n"
 159 "    be useful for allowing network access to 'servers' where only the server\n"
 160 "    needs to authenticate the client (ie. the other way is not required).\n"
 161 "    Even with client and server authentication, this 'technique' mitigates\n"
 162 "    some DoS (denial-of-service) potential as it will be the network client\n"
 163 "    having to perform the first private key operation rather than the other\n"
 164 "    way round.\n"
 165 "(4) The 'technique' used by setting '-flipped 1' is probably compatible with\n"
 166 "    absolutely nothing except another complimentary instance of 'tunala'\n"
 167 "    running with '-flipped 1'. :-)\n";
 168
 169 /* Default DH parameters for use with "-dh_special standard" ... stolen striaght
 170  * from s_server. */
 171 static unsigned char dh512_p[]={
 172         0xDA,0x58,0x3C,0x16,0xD9,0x85,0x22,0x89,0xD0,0xE4,0xAF,0x75,
 173         0x6F,0x4C,0xCA,0x92,0xDD,0x4B,0xE5,0x33,0xB8,0x04,0xFB,0x0F,
 174         0xED,0x94,0xEF,0x9C,0x8A,0x44,0x03,0xED,0x57,0x46,0x50,0xD3,
 175         0x69,0x99,0xDB,0x29,0xD7,0x76,0x27,0x6B,0xA2,0xD3,0xD4,0x12,
 176         0xE2,0x18,0xF4,0xDD,0x1E,0x08,0x4C,0xF6,0xD8,0x00,0x3E,0x7C,
 177         0x47,0x74,0xE8,0x33,
 178         };
 179 static unsigned char dh512_g[]={
 180         0x02,
 181         };
 182
 183 /* And the function that parses the above "standard" parameters, again, straight
 184  * out of s_server. */
 185 static DH *get_dh512(void)
 186         {
 187         DH *dh=NULL;
 188
 189         if ((dh=DH_new()) == NULL) return(NULL);
 190         dh->p=BN_bin2bn(dh512_p,sizeof(dh512_p),NULL);
 191         dh->g=BN_bin2bn(dh512_g,sizeof(dh512_g),NULL);
 192         if ((dh->p == NULL) || (dh->g == NULL))
 193                 return(NULL);
 194         return(dh);
 195         }
 196
 197 /* Various help/error messages used by main() */
 198 static int usage(const char *errstr, int isunknownarg)
 199 {
 200         if(isunknownarg)
 201                 fprintf(stderr, "Error: unknown argument '%s'\n", errstr);
 202         else
 203                 fprintf(stderr, "Error: %s\n", errstr);
 204         fprintf(stderr, "%s\n", helpstring);
 205         return 1;
 206 }
 207
 208 static int err_str0(const char *str0)
 209 {
 210         fprintf(stderr, "%s\n", str0);
 211         return 1;
 212 }
 213
 214 static int err_str1(const char *fmt, const char *str1)
 215 {
 216         fprintf(stderr, fmt, str1);
 217         fprintf(stderr, "\n");
 218         return 1;
 219 }
 220
 221 static int parse_max_tunnels(const char *s, unsigned int *maxtunnels)
 222 {
 223         unsigned long l;
 224         if(!int_strtoul(s, &l) || (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         if(!int_strtoul(s, &l) || (l > 1)) {
 237                 fprintf(stderr, "Error, '%s' is an invalid value for the "
 238                                 "server mode\n", s);
 239                 return 0;
 240         }
 241         *servermode = (int)l;
 242         return 1;
 243 }
 244
 245 static int parse_dh_special(const char *s, const char **dh_special)
 246 {
 247         if((strcmp(s, "NULL") == 0) || (strcmp(s, "generate") == 0) ||
 248                         (strcmp(s, "standard") == 0)) {
 249                 *dh_special = s;
 250                 return 1;
 251         }
 252         fprintf(stderr, "Error, '%s' is an invalid value for 'dh_special'\n", s);
 253         return 0;
 254 }
 255
 256 static int parse_verify_level(const char *s, unsigned int *verify_level)
 257 {
 258         unsigned long l;
 259         if(!int_strtoul(s, &l) || (l > 3)) {
 260                 fprintf(stderr, "Error, '%s' is an invalid value for "
 261                                 "out_verify\n", s);
 262                 return 0;
 263         }
 264         *verify_level = (unsigned int)l;
 265         return 1;
 266 }
 267
 268 static int parse_verify_depth(const char *s, unsigned int *verify_depth)
 269 {
 270         unsigned long l;
 271         if(!int_strtoul(s, &l) || (l < 1) || (l > 50)) {
 272                 fprintf(stderr, "Error, '%s' is an invalid value for "
 273                                 "verify_depth\n", s);
 274                 return 0;
 275         }
 276         *verify_depth = (unsigned int)l;
 277         return 1;
 278 }
 279
 280 /* Some fprintf format strings used when tunnels close */
 281 static const char *io_stats_dirty =
 282 "    SSL traffic;   %8lu bytes in, %8lu bytes out\n";
 283 static const char *io_stats_clean =
 284 "    clear traffic; %8lu bytes in, %8lu bytes out\n";
 285
 286 int main(int argc, char *argv[])
 287 {
 288         unsigned int loop;
 289         int newfd;
 290         tunala_world_t world;
 291         tunala_item_t *t_item;
 292         const char *proxy_ip;
 293         unsigned short proxy_port;
 294         /* Overridables */
 295         const char *proxyhost = def_proxyhost;
 296         const char *listenhost = def_listenhost;
 297         unsigned int max_tunnels = def_max_tunnels;
 298         const char *cacert = def_cacert;
 299         const char *cert = def_cert;
 300         const char *key = def_key;
 301         const char *dcert = def_dcert;
 302         const char *dkey = def_dkey;
 303         const char *engine_id = def_engine_id;
 304         int server_mode = def_server_mode;
 305         int flipped = def_flipped;
 306         const char *cipher_list = def_cipher_list;
 307         const char *dh_file = def_dh_file;
 308         const char *dh_special = def_dh_special;
 309         int ctx_options = def_ctx_options;
 310         int verify_mode = def_verify_mode;
 311         unsigned int verify_depth = def_verify_depth;
 312         int out_state = def_out_state;
 313         unsigned int out_verify = def_out_verify;
 314         int out_totals = def_out_totals;
 315         int out_conns = def_out_conns;
 316
 317 /* Parse command-line arguments */
 318 next_arg:
 319         argc--; argv++;
 320         if(argc > 0) {
 321                 if(strcmp(*argv, "-listen") == 0) {
 322                         if(argc < 2)
 323                                 return usage("-listen requires an argument", 0);
 324                         argc--; argv++;
 325                         listenhost = *argv;
 326                         goto next_arg;
 327                 } else if(strcmp(*argv, "-proxy") == 0) {
 328                         if(argc < 2)
 329                                 return usage("-proxy requires an argument", 0);
 330                         argc--; argv++;
 331                         proxyhost = *argv;
 332                         goto next_arg;
 333                 } else if(strcmp(*argv, "-maxtunnels") == 0) {
 334                         if(argc < 2)
 335                                 return usage("-maxtunnels requires an argument", 0);
 336                         argc--; argv++;
 337                         if(!parse_max_tunnels(*argv, &max_tunnels))
 338                                 return 1;
 339                         goto next_arg;
 340                 } else if(strcmp(*argv, "-cacert") == 0) {
 341                         if(argc < 2)
 342                                 return usage("-cacert requires an argument", 0);
 343                         argc--; argv++;
 344                         if(strcmp(*argv, "NULL") == 0)
 345                                 cacert = NULL;
 346                         else
 347                                 cacert = *argv;
 348                         goto next_arg;
 349                 } else if(strcmp(*argv, "-cert") == 0) {
 350                         if(argc < 2)
 351                                 return usage("-cert requires an argument", 0);
 352                         argc--; argv++;
 353                         if(strcmp(*argv, "NULL") == 0)
 354                                 cert = NULL;
 355                         else
 356                                 cert = *argv;
 357                         goto next_arg;
 358                 } else if(strcmp(*argv, "-key") == 0) {
 359                         if(argc < 2)
 360                                 return usage("-key requires an argument", 0);
 361                         argc--; argv++;
 362                         if(strcmp(*argv, "NULL") == 0)
 363                                 key = NULL;
 364                         else
 365                                 key = *argv;
 366                         goto next_arg;
 367                 } else if(strcmp(*argv, "-dcert") == 0) {
 368                         if(argc < 2)
 369                                 return usage("-dcert requires an argument", 0);
 370                         argc--; argv++;
 371                         if(strcmp(*argv, "NULL") == 0)
 372                                 dcert = NULL;
 373                         else
 374                                 dcert = *argv;
 375                         goto next_arg;
 376                 } else if(strcmp(*argv, "-dkey") == 0) {
 377                         if(argc < 2)
 378                                 return usage("-dkey requires an argument", 0);
 379                         argc--; argv++;
 380                         if(strcmp(*argv, "NULL") == 0)
 381                                 dkey = NULL;
 382                         else
 383                                 dkey = *argv;
 384                         goto next_arg;
 385                 } else if(strcmp(*argv, "-engine") == 0) {
 386                         if(argc < 2)
 387                                 return usage("-engine requires an argument", 0);
 388                         argc--; argv++;
 389                         engine_id = *argv;
 390                         goto next_arg;
 391                 } else if(strcmp(*argv, "-server") == 0) {
 392                         if(argc < 2)
 393                                 return usage("-server requires an argument", 0);
 394                         argc--; argv++;
 395                         if(!parse_server_mode(*argv, &server_mode))
 396                                 return 1;
 397                         goto next_arg;
 398                 } else if(strcmp(*argv, "-flipped") == 0) {
 399                         if(argc < 2)
 400                                 return usage("-flipped requires an argument", 0);
 401                         argc--; argv++;
 402                         if(!parse_server_mode(*argv, &flipped))
 403                                 return 1;
 404                         goto next_arg;
 405                 } else if(strcmp(*argv, "-cipher") == 0) {
 406                         if(argc < 2)
 407                                 return usage("-cipher requires an argument", 0);
 408                         argc--; argv++;
 409                         cipher_list = *argv;
 410                         goto next_arg;
 411                 } else if(strcmp(*argv, "-dh_file") == 0) {
 412                         if(argc < 2)
 413                                 return usage("-dh_file requires an argument", 0);
 414                         if(dh_special)
 415                                 return usage("cannot mix -dh_file with "
 416                                                 "-dh_special", 0);
 417                         argc--; argv++;
 418                         dh_file = *argv;
 419                         goto next_arg;
 420                 } else if(strcmp(*argv, "-dh_special") == 0) {
 421                         if(argc < 2)
 422                                 return usage("-dh_special requires an argument", 0);
 423                         if(dh_file)
 424                                 return usage("cannot mix -dh_file with "
 425                                                 "-dh_special", 0);
 426                         argc--; argv++;
 427                         if(!parse_dh_special(*argv, &dh_special))
 428                                 return 1;
 429                         goto next_arg;
 430                 } else if(strcmp(*argv, "-no_ssl2") == 0) {
 431                         ctx_options |= SSL_OP_NO_SSLv2;
 432                         goto next_arg;
 433                 } else if(strcmp(*argv, "-no_ssl3") == 0) {
 434                         ctx_options |= SSL_OP_NO_SSLv3;
 435                         goto next_arg;
 436                 } else if(strcmp(*argv, "-no_tls1") == 0) {
 437                         ctx_options |= SSL_OP_NO_TLSv1;
 438                         goto next_arg;
 439                 } else if(strcmp(*argv, "-v_peer") == 0) {
 440                         verify_mode |= SSL_VERIFY_PEER;
 441                         goto next_arg;
 442                 } else if(strcmp(*argv, "-v_strict") == 0) {
 443                         verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
 444                         goto next_arg;
 445                 } else if(strcmp(*argv, "-v_once") == 0) {
 446                         verify_mode |= SSL_VERIFY_CLIENT_ONCE;
 447                         goto next_arg;
 448                 } else if(strcmp(*argv, "-v_depth") == 0) {
 449                         if(argc < 2)
 450                                 return usage("-v_depth requires an argument", 0);
 451                         argc--; argv++;
 452                         if(!parse_verify_depth(*argv, &verify_depth))
 453                                 return 1;
 454                         goto next_arg;
 455                 } else if(strcmp(*argv, "-out_state") == 0) {
 456                         out_state = 1;
 457                         goto next_arg;
 458                 } else if(strcmp(*argv, "-out_verify") == 0) {
 459                         if(argc < 2)
 460                                 return usage("-out_verify requires an argument", 0);
 461                         argc--; argv++;
 462                         if(!parse_verify_level(*argv, &out_verify))
 463                                 return 1;
 464                         goto next_arg;
 465                 } else if(strcmp(*argv, "-out_totals") == 0) {
 466                         out_totals = 1;
 467                         goto next_arg;
 468                 } else if(strcmp(*argv, "-out_conns") == 0) {
 469                         out_conns = 1;
 470                         goto next_arg;
 471                 } else if((strcmp(*argv, "-h") == 0) ||
 472                                 (strcmp(*argv, "-help") == 0) ||
 473                                 (strcmp(*argv, "-?") == 0)) {
 474                         fprintf(stderr, "%s\n", helpstring);
 475                         return 0;
 476                 } else
 477                         return usage(*argv, 1);
 478         }
 479         /* Run any sanity checks we want here */
 480         if(!cert && !dcert && server_mode)
 481                 fprintf(stderr, "WARNING: you are running an SSL server without "
 482                                 "a certificate - this may not work!\n");
 483
 484         /* Initialise network stuff */
 485         if(!ip_initialise())
 486                 return err_str0("ip_initialise failed");
 487         /* Create the SSL_CTX */
 488         if((world.ssl_ctx = initialise_ssl_ctx(server_mode, engine_id,
 489                         cacert, cert, key, dcert, dkey, cipher_list, dh_file,
 490                         dh_special, ctx_options, out_state, out_verify,
 491                         verify_mode, verify_depth)) == NULL)
 492                 return err_str1("initialise_ssl_ctx(engine_id=%s) failed",
 493                         (engine_id == NULL) ? "NULL" : engine_id);
 494         if(engine_id)
 495                 fprintf(stderr, "Info, engine '%s' initialised\n", engine_id);
 496         /* Create the listener */
 497         if((world.listen_fd = ip_create_listener(listenhost)) == -1)
 498                 return err_str1("ip_create_listener(%s) failed", listenhost);
 499         fprintf(stderr, "Info, listening on '%s'\n", listenhost);
 500         if(!ip_parse_address(proxyhost, &proxy_ip, &proxy_port, 0))
 501                 return err_str1("ip_parse_address(%s) failed", proxyhost);
 502         fprintf(stderr, "Info, proxying to '%s' (%d.%d.%d.%d:%d)\n", proxyhost,
 503                         (int)proxy_ip[0], (int)proxy_ip[1],
 504                         (int)proxy_ip[2], (int)proxy_ip[3], (int)proxy_port);
 505         fprintf(stderr, "Info, set maxtunnels to %d\n", (int)max_tunnels);
 506         fprintf(stderr, "Info, set to operate as an SSL %s\n",
 507                         (server_mode ? "server" : "client"));
 508         /* Initialise the rest of the stuff */
 509         world.tunnels_used = world.tunnels_size = 0;
 510         world.tunnels = NULL;
 511         world.server_mode = server_mode;
 512         selector_init(&world.selector);
 513
 514 /* We're ready to loop */
 515 main_loop:
 516         /* Should we listen for *new* tunnels? */
 517         if(world.tunnels_used < max_tunnels)
 518                 selector_add_listener(&world.selector, world.listen_fd);
 519         /* We should add in our existing tunnels */
 520         for(loop = 0; loop < world.tunnels_used; loop++)
 521                 selector_add_tunala(&world.selector, world.tunnels + loop);
 522         /* Now do the select */
 523         switch(selector_select(&world.selector)) {
 524         case -1:
 525                 fprintf(stderr, "selector_select returned a badness error.\n");
 526                 goto shouldnt_happen;
 527         case 0:
 528                 fprintf(stderr, "Warn, selector_select returned 0 - signal?""?\n");
 529                 goto main_loop;
 530         default:
 531                 break;
 532         }
 533         /* Accept new connection if we should and can */
 534         if((world.tunnels_used < max_tunnels) && (selector_get_listener(
 535                                         &world.selector, world.listen_fd,
 536                                         &newfd) == 1)) {
 537                 /* We have a new connection */
 538                 if(!tunala_world_new_item(&world, newfd, proxy_ip,
 539                                                 proxy_port, flipped))
 540                         fprintf(stderr, "tunala_world_new_item failed\n");
 541                 else if(out_conns)
 542                         fprintf(stderr, "Info, new tunnel opened, now up to "
 543                                         "%d\n", world.tunnels_used);
 544         }
 545         /* Give each tunnel its moment, note the while loop is because it makes
 546          * the logic easier than with "for" to deal with an array that may shift
 547          * because of deletes. */
 548         loop = 0;
 549         t_item = world.tunnels;
 550         while(loop < world.tunnels_used) {
 551                 if(!tunala_item_io(&world.selector, t_item)) {
 552                         /* We're closing whether for reasons of an error or a
 553                          * natural close. Don't increment loop or t_item because
 554                          * the next item is moving to us! */
 555                         if(!out_totals)
 556                                 goto skip_totals;
 557                         fprintf(stderr, "Tunnel closing, traffic stats follow\n");
 558                         /* Display the encrypted (over the network) stats */
 559                         fprintf(stderr, io_stats_dirty,
 560                                 buffer_total_in(state_machine_get_buffer(
 561                                                 &t_item->sm,SM_DIRTY_IN)),
 562                                 buffer_total_out(state_machine_get_buffer(
 563                                                 &t_item->sm,SM_DIRTY_OUT)));
 564                         /* Display the local (tunnelled) stats. NB: Data we
 565                          * *receive* is data sent *out* of the state_machine on
 566                          * its 'clean' side. Hence the apparent back-to-front
 567                          * OUT/IN mixup here :-) */
 568                         fprintf(stderr, io_stats_clean,
 569                                 buffer_total_out(state_machine_get_buffer(
 570                                                 &t_item->sm,SM_CLEAN_OUT)),
 571                                 buffer_total_in(state_machine_get_buffer(
 572                                                 &t_item->sm,SM_CLEAN_IN)));
 573 skip_totals:
 574                         tunala_world_del_item(&world, loop);
 575                         if(out_conns)
 576                                 fprintf(stderr, "Info, tunnel closed, down to %d\n",
 577                                         world.tunnels_used);
 578                 }
 579                 else {
 580                         /* Move to the next item */
 581                         loop++;
 582                         t_item++;
 583                 }
 584         }
 585         goto main_loop;
 586         /* Should never get here */
 587 shouldnt_happen:
 588         abort();
 589         return 1;
 590 }
 591
 592 /****************/
 593 /* OpenSSL bits */
 594 /****************/
 595
 596 static int ctx_set_cert(SSL_CTX *ctx, const char *cert, const char *key)
 597 {
 598         FILE *fp = NULL;
 599         X509 *x509 = NULL;
 600         EVP_PKEY *pkey = NULL;
 601         int toret = 0; /* Assume an error */
 602
 603         /* cert */
 604         if(cert) {
 605                 if((fp = fopen(cert, "r")) == NULL) {
 606                         fprintf(stderr, "Error opening cert file '%s'\n", cert);
 607                         goto err;
 608                 }
 609                 if(!PEM_read_X509(fp, &x509, NULL, NULL)) {
 610                         fprintf(stderr, "Error reading PEM cert from '%s'\n",
 611                                         cert);
 612                         goto err;
 613                 }
 614                 if(!SSL_CTX_use_certificate(ctx, x509)) {
 615                         fprintf(stderr, "Error, cert in '%s' can not be used\n",
 616                                         cert);
 617                         goto err;
 618                 }
 619                 /* Clear the FILE* for reuse in the "key" code */
 620                 fclose(fp);
 621                 fp = NULL;
 622                 fprintf(stderr, "Info, operating with cert in '%s'\n", cert);
 623                 /* If a cert was given without matching key, we assume the same
 624                  * file contains the required key. */
 625                 if(!key)
 626                         key = cert;
 627         } else {
 628                 if(key)
 629                         fprintf(stderr, "Error, can't specify a key without a "
 630                                         "corresponding certificate\n");
 631                 else
 632                         fprintf(stderr, "Error, ctx_set_cert called with "
 633                                         "NULLs!\n");
 634                 goto err;
 635         }
 636         /* key */
 637         if(key) {
 638                 if((fp = fopen(key, "r")) == NULL) {
 639                         fprintf(stderr, "Error opening key file '%s'\n", key);
 640                         goto err;
 641                 }
 642                 if(!PEM_read_PrivateKey(fp, &pkey, NULL, NULL)) {
 643                         fprintf(stderr, "Error reading PEM key from '%s'\n",
 644                                         key);
 645                         goto err;
 646                 }
 647                 if(!SSL_CTX_use_PrivateKey(ctx, pkey)) {
 648                         fprintf(stderr, "Error, key in '%s' can not be used\n",
 649                                         key);
 650                         goto err;
 651                 }
 652                 fprintf(stderr, "Info, operating with key in '%s'\n", key);
 653         } else
 654                 fprintf(stderr, "Info, operating without a cert or key\n");
 655         /* Success */
 656         toret = 1; err:
 657         if(x509)
 658                 X509_free(x509);
 659         if(pkey)
 660                 EVP_PKEY_free(pkey);
 661         if(fp)
 662                 fclose(fp);
 663         return toret;
 664 }
 665
 666 static int ctx_set_dh(SSL_CTX *ctx, const char *dh_file, const char *dh_special)
 667 {
 668         DH *dh = NULL;
 669         FILE *fp = NULL;
 670
 671         if(dh_special) {
 672                 if(strcmp(dh_special, "NULL") == 0)
 673                         return 1;
 674                 if(strcmp(dh_special, "standard") == 0) {
 675                         if((dh = get_dh512()) == NULL) {
 676                                 fprintf(stderr, "Error, can't parse 'standard'"
 677                                                 " DH parameters\n");
 678                                 return 0;
 679                         }
 680                         fprintf(stderr, "Info, using 'standard' DH parameters\n");
 681                         goto do_it;
 682                 }
 683                 if(strcmp(dh_special, "generate") != 0)
 684                         /* This shouldn't happen - screening values is handled
 685                          * in main(). */
 686                         abort();
 687                 fprintf(stderr, "Info, generating DH parameters ... ");
 688                 fflush(stderr);
 689                 if((dh = DH_generate_parameters(512, DH_GENERATOR_5,
 690                                         NULL, NULL)) == NULL) {
 691                         fprintf(stderr, "error!\n");
 692                         return 0;
 693                 }
 694                 fprintf(stderr, "complete\n");
 695                 goto do_it;
 696         }
 697         /* So, we're loading dh_file */
 698         if((fp = fopen(dh_file, "r")) == NULL) {
 699                 fprintf(stderr, "Error, couldn't open '%s' for DH parameters\n",
 700                                 dh_file);
 701                 return 0;
 702         }
 703         dh = PEM_read_DHparams(fp, NULL, NULL, NULL);
 704         fclose(fp);
 705         if(dh == NULL) {
 706                 fprintf(stderr, "Error, could not parse DH parameters from '%s'\n",
 707                                 dh_file);
 708                 return 0;
 709         }
 710         fprintf(stderr, "Info, using DH parameters from file '%s'\n", dh_file);
 711 do_it:
 712         SSL_CTX_set_tmp_dh(ctx, dh);
 713         DH_free(dh);
 714         return 1;
 715 }
 716
 717 static SSL_CTX *initialise_ssl_ctx(int server_mode, const char *engine_id,
 718                 const char *CAfile, const char *cert, const char *key,
 719                 const char *dcert, const char *dkey, const char *cipher_list,
 720                 const char *dh_file, const char *dh_special, int ctx_options,
 721                 int out_state, int out_verify, int verify_mode,
 722                 unsigned int verify_depth)
 723 {
 724         SSL_CTX *ctx = NULL, *ret = NULL;
 725         SSL_METHOD *meth;
 726         ENGINE *e = NULL;
 727
 728         OpenSSL_add_ssl_algorithms();
 729         SSL_load_error_strings();
 730
 731         meth = (server_mode ? SSLv23_server_method() : SSLv23_client_method());
 732         if(meth == NULL)
 733                 goto err;
 734         if(engine_id) {
 735                 ENGINE_load_builtin_engines();
 736                 if((e = ENGINE_by_id(engine_id)) == NULL) {
 737                         fprintf(stderr, "Error obtaining '%s' engine, openssl "
 738                                         "errors follow\n", engine_id);
 739                         goto err;
 740                 }
 741                 if(!ENGINE_set_default(e, ENGINE_METHOD_ALL)) {
 742                         fprintf(stderr, "Error assigning '%s' engine, openssl "
 743                                         "errors follow\n", engine_id);
 744                         goto err;
 745                 }
 746                 ENGINE_free(e);
 747         }
 748         if((ctx = SSL_CTX_new(meth)) == NULL)
 749                 goto err;
 750         /* cacert */
 751         if(CAfile) {
 752                 if(!X509_STORE_load_locations(SSL_CTX_get_cert_store(ctx),
 753                                         CAfile, NULL)) {
 754                         fprintf(stderr, "Error loading CA cert(s) in '%s'\n",
 755                                         CAfile);
 756                         goto err;
 757                 }
 758                 fprintf(stderr, "Info, operating with CA cert(s) in '%s'\n",
 759                                 CAfile);
 760         } else
 761                 fprintf(stderr, "Info, operating without a CA cert(-list)\n");
 762         if(!SSL_CTX_set_default_verify_paths(ctx)) {
 763                 fprintf(stderr, "Error setting default verify paths\n");
 764                 goto err;
 765         }
 766
 767         /* cert and key */
 768         if((cert || key) && !ctx_set_cert(ctx, cert, key))
 769                 goto err;
 770         /* dcert and dkey */
 771         if((dcert || dkey) && !ctx_set_cert(ctx, dcert, dkey))
 772                 goto err;
 773
 774         /* cipher_list */
 775         if(cipher_list) {
 776                 if(!SSL_CTX_set_cipher_list(ctx, cipher_list)) {
 777                         fprintf(stderr, "Error setting cipher list '%s'\n",
 778                                         cipher_list);
 779                         goto err;
 780                 }
 781                 fprintf(stderr, "Info, set cipher list '%s'\n", cipher_list);
 782         } else
 783                 fprintf(stderr, "Info, operating with default cipher list\n");
 784
 785         /* dh_file & dh_special */
 786         if((dh_file || dh_special) && !ctx_set_dh(ctx, dh_file, dh_special))
 787                 goto err;
 788
 789         /* ctx_options */
 790         SSL_CTX_set_options(ctx, ctx_options);
 791
 792         /* out_state (output of SSL handshake states to screen). */
 793         if(out_state)
 794                 cb_ssl_info_set_output(stderr);
 795
 796         /* out_verify */
 797         if(out_verify > 0) {
 798                 cb_ssl_verify_set_output(stderr);
 799                 cb_ssl_verify_set_level(out_verify);
 800         }
 801
 802         /* verify_depth */
 803         cb_ssl_verify_set_depth(verify_depth);
 804
 805         /* Success! (includes setting verify_mode) */
 806         SSL_CTX_set_info_callback(ctx, cb_ssl_info);
 807         SSL_CTX_set_verify(ctx, verify_mode, cb_ssl_verify);
 808         ret = ctx;
 809 err:
 810         if(!ret) {
 811                 ERR_print_errors_fp(stderr);
 812                 if(ctx)
 813                         SSL_CTX_free(ctx);
 814         }
 815         return ret;
 816 }
 817
 818 /*****************/
 819 /* Selector bits */
 820 /*****************/
 821
 822 static void selector_sets_init(select_sets_t *s)
 823 {
 824         s->max = 0;
 825         FD_ZERO(&s->reads);
 826         FD_ZERO(&s->sends);
 827         FD_ZERO(&s->excepts);
 828 }
 829 static void selector_init(tunala_selector_t *selector)
 830 {
 831         selector_sets_init(&selector->last_selected);
 832         selector_sets_init(&selector->next_select);
 833 }
 834
 835 #define SEL_EXCEPTS 0x00
 836 #define SEL_READS   0x01
 837 #define SEL_SENDS   0x02
 838 static void selector_add_raw_fd(tunala_selector_t *s, int fd, int flags)
 839 {
 840         FD_SET(fd, &s->next_select.excepts);
 841         if(flags & SEL_READS)
 842                 FD_SET(fd, &s->next_select.reads);
 843         if(flags & SEL_SENDS)
 844                 FD_SET(fd, &s->next_select.sends);
 845         /* Adjust "max" */
 846         if(s->next_select.max < (fd + 1))
 847                 s->next_select.max = fd + 1;
 848 }
 849
 850 static void selector_add_listener(tunala_selector_t *selector, int fd)
 851 {
 852         selector_add_raw_fd(selector, fd, SEL_READS);
 853 }
 854
 855 static void selector_add_tunala(tunala_selector_t *s, tunala_item_t *t)
 856 {
 857         /* Set clean read if sm.clean_in is not full */
 858         if(t->clean_read != -1) {
 859                 selector_add_raw_fd(s, t->clean_read,
 860                         (buffer_full(state_machine_get_buffer(&t->sm,
 861                                 SM_CLEAN_IN)) ? SEL_EXCEPTS : SEL_READS));
 862         }
 863         /* Set clean send if sm.clean_out is not empty */
 864         if(t->clean_send != -1) {
 865                 selector_add_raw_fd(s, t->clean_send,
 866                         (buffer_empty(state_machine_get_buffer(&t->sm,
 867                                 SM_CLEAN_OUT)) ? SEL_EXCEPTS : SEL_SENDS));
 868         }
 869         /* Set dirty read if sm.dirty_in is not full */
 870         if(t->dirty_read != -1) {
 871                 selector_add_raw_fd(s, t->dirty_read,
 872                         (buffer_full(state_machine_get_buffer(&t->sm,
 873                                 SM_DIRTY_IN)) ? SEL_EXCEPTS : SEL_READS));
 874         }
 875         /* Set dirty send if sm.dirty_out is not empty */
 876         if(t->dirty_send != -1) {
 877                 selector_add_raw_fd(s, t->dirty_send,
 878                         (buffer_empty(state_machine_get_buffer(&t->sm,
 879                                 SM_DIRTY_OUT)) ? SEL_EXCEPTS : SEL_SENDS));
 880         }
 881 }
 882
 883 static int selector_select(tunala_selector_t *selector)
 884 {
 885         memcpy(&selector->last_selected, &selector->next_select,
 886                         sizeof(select_sets_t));
 887         selector_sets_init(&selector->next_select);
 888         return select(selector->last_selected.max,
 889                         &selector->last_selected.reads,
 890                         &selector->last_selected.sends,
 891                         &selector->last_selected.excepts, NULL);
 892 }
 893
 894 /* This returns -1 for error, 0 for no new connections, or 1 for success, in
 895  * which case *newfd is populated. */
 896 static int selector_get_listener(tunala_selector_t *selector, int fd, int *newfd)
 897 {
 898         if(FD_ISSET(fd, &selector->last_selected.excepts))
 899                 return -1;
 900         if(!FD_ISSET(fd, &selector->last_selected.reads))
 901                 return 0;
 902         if((*newfd = ip_accept_connection(fd)) == -1)
 903                 return -1;
 904         return 1;
 905 }
 906
 907 /************************/
 908 /* "Tunala" world stuff */
 909 /************************/
 910
 911 static int tunala_world_make_room(tunala_world_t *world)
 912 {
 913         unsigned int newsize;
 914         tunala_item_t *newarray;
 915
 916         if(world->tunnels_used < world->tunnels_size)
 917                 return 1;
 918         newsize = (world->tunnels_size == 0 ? 16 :
 919                         ((world->tunnels_size * 3) / 2));
 920         if((newarray = malloc(newsize * sizeof(tunala_item_t))) == NULL)
 921                 return 0;
 922         memset(newarray, 0, newsize * sizeof(tunala_item_t));
 923         if(world->tunnels_used > 0)
 924                 memcpy(newarray, world->tunnels,
 925                         world->tunnels_used * sizeof(tunala_item_t));
 926         if(world->tunnels_size > 0)
 927                 free(world->tunnels);
 928         /* migrate */
 929         world->tunnels = newarray;
 930         world->tunnels_size = newsize;
 931         return 1;
 932 }
 933
 934 static int tunala_world_new_item(tunala_world_t *world, int fd,
 935                 const char *ip, unsigned short port, int flipped)
 936 {
 937         tunala_item_t *item;
 938         int newfd;
 939         SSL *new_ssl = NULL;
 940
 941         if(!tunala_world_make_room(world))
 942                 return 0;
 943         if((new_ssl = SSL_new(world->ssl_ctx)) == NULL) {
 944                 fprintf(stderr, "Error creating new SSL\n");
 945                 ERR_print_errors_fp(stderr);
 946                 return 0;
 947         }
 948         item = world->tunnels + (world->tunnels_used++);
 949         state_machine_init(&item->sm);
 950         item->clean_read = item->clean_send =
 951                 item->dirty_read = item->dirty_send = -1;
 952         if((newfd = ip_create_connection_split(ip, port)) == -1)
 953                 goto err;
 954         /* Which way round? If we're a server, "fd" is the dirty side and the
 955          * connection we open is the clean one. For a client, it's the other way
 956          * around. Unless, of course, we're "flipped" in which case everything
 957          * gets reversed. :-) */
 958         if((world->server_mode && !flipped) ||
 959                         (!world->server_mode && flipped)) {
 960                 item->dirty_read = item->dirty_send = fd;
 961                 item->clean_read = item->clean_send = newfd;
 962         } else {
 963                 item->clean_read = item->clean_send = fd;
 964                 item->dirty_read = item->dirty_send = newfd;
 965         }
 966         /* We use the SSL's "app_data" to indicate a call-back induced "kill" */
 967         SSL_set_app_data(new_ssl, NULL);
 968         if(!state_machine_set_SSL(&item->sm, new_ssl, world->server_mode))
 969                 goto err;
 970         return 1;
 971 err:
 972         tunala_world_del_item(world, world->tunnels_used - 1);
 973         return 0;
 974
 975 }
 976
 977 static void tunala_world_del_item(tunala_world_t *world, unsigned int idx)
 978 {
 979         tunala_item_t *item = world->tunnels + idx;
 980         if(item->clean_read != -1)
 981                 close(item->clean_read);
 982         if(item->clean_send != item->clean_read)
 983                 close(item->clean_send);
 984         item->clean_read = item->clean_send = -1;
 985         if(item->dirty_read != -1)
 986                 close(item->dirty_read);
 987         if(item->dirty_send != item->dirty_read)
 988                 close(item->dirty_send);
 989         item->dirty_read = item->dirty_send = -1;
 990         state_machine_close(&item->sm);
 991         /* OK, now we fix the item array */
 992         if(idx + 1 < world->tunnels_used)
 993                 /* We need to scroll entries to the left */
 994                 memmove(world->tunnels + idx,
 995                                 world->tunnels + (idx + 1),
 996                                 (world->tunnels_used - (idx + 1)) *
 997                                         sizeof(tunala_item_t));
 998         world->tunnels_used--;
 999 }
1000
1001 static int tunala_item_io(tunala_selector_t *selector, tunala_item_t *item)
1002 {
1003         int c_r, c_s, d_r, d_s; /* Four boolean flags */
1004
1005         /* Take ourselves out of the gene-pool if there was an except */
1006         if((item->clean_read != -1) && FD_ISSET(item->clean_read,
1007                                 &selector->last_selected.excepts))
1008                 return 0;
1009         if((item->clean_send != -1) && FD_ISSET(item->clean_send,
1010                                 &selector->last_selected.excepts))
1011                 return 0;
1012         if((item->dirty_read != -1) && FD_ISSET(item->dirty_read,
1013                                 &selector->last_selected.excepts))
1014                 return 0;
1015         if((item->dirty_send != -1) && FD_ISSET(item->dirty_send,
1016                                 &selector->last_selected.excepts))
1017                 return 0;
1018         /* Grab our 4 IO flags */
1019         c_r = c_s = d_r = d_s = 0;
1020         if(item->clean_read != -1)
1021                 c_r = FD_ISSET(item->clean_read, &selector->last_selected.reads);
1022         if(item->clean_send != -1)
1023                 c_s = FD_ISSET(item->clean_send, &selector->last_selected.sends);
1024         if(item->dirty_read != -1)
1025                 d_r = FD_ISSET(item->dirty_read, &selector->last_selected.reads);
1026         if(item->dirty_send != -1)
1027                 d_s = FD_ISSET(item->dirty_send, &selector->last_selected.sends);
1028         /* If no IO has happened for us, skip needless data looping */
1029         if(!c_r && !c_s && !d_r && !d_s)
1030                 return 1;
1031         if(c_r)
1032                 c_r = (buffer_from_fd(state_machine_get_buffer(&item->sm,
1033                                 SM_CLEAN_IN), item->clean_read) <= 0);
1034         if(c_s)
1035                 c_s = (buffer_to_fd(state_machine_get_buffer(&item->sm,
1036                                 SM_CLEAN_OUT), item->clean_send) <= 0);
1037         if(d_r)
1038                 d_r = (buffer_from_fd(state_machine_get_buffer(&item->sm,
1039                                 SM_DIRTY_IN), item->dirty_read) <= 0);
1040         if(d_s)
1041                 d_s = (buffer_to_fd(state_machine_get_buffer(&item->sm,
1042                                 SM_DIRTY_OUT), item->dirty_send) <= 0);
1043         /* If any of the flags is non-zero, that means they need closing */
1044         if(c_r) {
1045                 close(item->clean_read);
1046                 if(item->clean_send == item->clean_read)
1047                         item->clean_send = -1;
1048                 item->clean_read = -1;
1049         }
1050         if(c_s && (item->clean_send != -1)) {
1051                 close(item->clean_send);
1052                 if(item->clean_send == item->clean_read)
1053                         item->clean_read = -1;
1054                 item->clean_send = -1;
1055         }
1056         if(d_r) {
1057                 close(item->dirty_read);
1058                 if(item->dirty_send == item->dirty_read)
1059                         item->dirty_send = -1;
1060                 item->dirty_read = -1;
1061         }
1062         if(d_s && (item->dirty_send != -1)) {
1063                 close(item->dirty_send);
1064                 if(item->dirty_send == item->dirty_read)
1065                         item->dirty_read = -1;
1066                 item->dirty_send = -1;
1067         }
1068         /* This function name is attributed to the term donated by David
1069          * Schwartz on openssl-dev, message-ID:
1070          * <NCBBLIEPOCNJOAEKBEAKEEDGLIAA.davids@webmaster.com>. :-) */
1071         if(!state_machine_churn(&item->sm))
1072                 /* If the SSL closes, it will also zero-out the _in buffers
1073                  * and will in future process just outgoing data. As and
1074                  * when the outgoing data has gone, it will return zero
1075                  * here to tell us to bail out. */
1076                 return 0;
1077         /* Otherwise, we return zero if both sides are dead. */
1078         if(((item->clean_read == -1) || (item->clean_send == -1)) &&
1079                         ((item->dirty_read == -1) || (item->dirty_send == -1)))
1080                 return 0;
1081         /* If only one side closed, notify the SSL of this so it can take
1082          * appropriate action. */
1083         if((item->clean_read == -1) || (item->clean_send == -1)) {
1084                 if(!state_machine_close_clean(&item->sm))
1085                         return 0;
1086         }
1087         if((item->dirty_read == -1) || (item->dirty_send == -1)) {
1088                 if(!state_machine_close_dirty(&item->sm))
1089                         return 0;
1090         }
1091         return 1;
1092 }
1093