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 tmp_rsa,
  73                 int ctx_options, 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_tmp_rsa = 1;
 106 static int def_ctx_options = 0;
 107 static int def_verify_mode = 0;
 108 static unsigned int def_verify_depth = 10;
 109 static int def_out_state = 0;
 110 static unsigned int def_out_verify = 0;
 111 static int def_out_totals = 0;
 112 static int def_out_conns = 0;
 113
 114 static const char *helpstring =
 115 "\n'Tunala' (A tunneler with a New Zealand accent)\n"
 116 "Usage: tunala [options], where options are from;\n"
 117 " -listen [host:]<port>  (default = 127.0.0.1:8080)\n"
 118 " -proxy <host>:<port>   (default = 127.0.0.1:443)\n"
 119 " -maxtunnels <num>      (default = 50)\n"
 120 " -cacert <path|NULL>    (default = NULL)\n"
 121 " -cert <path|NULL>      (default = NULL)\n"
 122 " -key <path|NULL>       (default = whatever '-cert' is)\n"
 123 " -dcert <path|NULL>     (usually for DSA, default = NULL)\n"
 124 " -dkey <path|NULL>      (usually for DSA, default = whatever '-dcert' is)\n"
 125 " -engine <id|NULL>      (default = NULL)\n"
 126 " -server <0|1>          (default = 0, ie. an SSL client)\n"
 127 " -flipped <0|1>         (makes SSL servers be network clients, and vice versa)\n"
 128 " -cipher <list>         (specifies cipher list to use)\n"
 129 " -dh_file <path>        (a PEM file containing DH parameters to use)\n"
 130 " -dh_special <NULL|generate|standard> (see below: def=NULL)\n"
 131 " -no_tmp_rsa            (don't generate temporary RSA keys)\n"
 132 " -no_ssl2               (disable SSLv2)\n"
 133 " -no_ssl3               (disable SSLv3)\n"
 134 " -no_tls1               (disable TLSv1)\n"
 135 " -v_peer                (verify the peer certificate)\n"
 136 " -v_strict              (do not continue if peer doesn't authenticate)\n"
 137 " -v_once                (no verification in renegotiates)\n"
 138 " -v_depth <num>         (limit certificate chain depth, default = 10)\n"
 139 " -out_conns             (prints client connections and disconnections)\n"
 140 " -out_state             (prints SSL handshake states)\n"
 141 " -out_verify <0|1|2|3>  (prints certificate verification states: def=1)\n"
 142 " -out_totals            (prints out byte-totals when a tunnel closes)\n"
 143 " -<h|help|?>            (displays this help screen)\n"
 144 "Notes:\n"
 145 "(1) It is recommended to specify a cert+key when operating as an SSL server.\n"
 146 "    If you only specify '-cert', the same file must contain a matching\n"
 147 "    private key.\n"
 148 "(2) Either dh_file or dh_special can be used to specify where DH parameters\n"
 149 "    will be obtained from (or '-dh_special NULL' for the default choice) but\n"
 150 "    you cannot specify both. For dh_special, 'generate' will create new DH\n"
 151 "    parameters on startup, and 'standard' will use embedded parameters\n"
 152 "    instead.\n"
 153 "(3) Normally an ssl client connects to an ssl server - so that an 'ssl client\n"
 154 "    tunala' listens for 'clean' client connections and proxies ssl, and an\n"
 155 "    'ssl server tunala' listens for ssl connections and proxies 'clean'. With\n"
 156 "    '-flipped 1', this behaviour is reversed so that an 'ssl server tunala'\n"
 157 "    listens for clean client connections and proxies ssl (but participating\n"
 158 "    as an ssl *server* in the SSL/TLS protocol), and an 'ssl client tunala'\n"
 159 "    listens for ssl connections (participating as an ssl *client* in the\n"
 160 "    SSL/TLS protocol) and proxies 'clean' to the end destination. This can\n"
 161 "    be useful for allowing network access to 'servers' where only the server\n"
 162 "    needs to authenticate the client (ie. the other way is not required).\n"
 163 "    Even with client and server authentication, this 'technique' mitigates\n"
 164 "    some DoS (denial-of-service) potential as it will be the network client\n"
 165 "    having to perform the first private key operation rather than the other\n"
 166 "    way round.\n"
 167 "(4) The 'technique' used by setting '-flipped 1' is probably compatible with\n"
 168 "    absolutely nothing except another complimentary instance of 'tunala'\n"
 169 "    running with '-flipped 1'. :-)\n";
 170
 171 /* Default DH parameters for use with "-dh_special standard" ... stolen striaght
 172  * from s_server. */
 173 static unsigned char dh512_p[]={
 174         0xDA,0x58,0x3C,0x16,0xD9,0x85,0x22,0x89,0xD0,0xE4,0xAF,0x75,
 175         0x6F,0x4C,0xCA,0x92,0xDD,0x4B,0xE5,0x33,0xB8,0x04,0xFB,0x0F,
 176         0xED,0x94,0xEF,0x9C,0x8A,0x44,0x03,0xED,0x57,0x46,0x50,0xD3,
 177         0x69,0x99,0xDB,0x29,0xD7,0x76,0x27,0x6B,0xA2,0xD3,0xD4,0x12,
 178         0xE2,0x18,0xF4,0xDD,0x1E,0x08,0x4C,0xF6,0xD8,0x00,0x3E,0x7C,
 179         0x47,0x74,0xE8,0x33,
 180         };
 181 static unsigned char dh512_g[]={
 182         0x02,
 183         };
 184
 185 /* And the function that parses the above "standard" parameters, again, straight
 186  * out of s_server. */
 187 static DH *get_dh512(void)
 188         {
 189         DH *dh=NULL;
 190
 191         if ((dh=DH_new()) == NULL) return(NULL);
 192         dh->p=BN_bin2bn(dh512_p,sizeof(dh512_p),NULL);
 193         dh->g=BN_bin2bn(dh512_g,sizeof(dh512_g),NULL);
 194         if ((dh->p == NULL) || (dh->g == NULL))
 195                 return(NULL);
 196         return(dh);
 197         }
 198
 199 /* Various help/error messages used by main() */
 200 static int usage(const char *errstr, int isunknownarg)
 201 {
 202         if(isunknownarg)
 203                 fprintf(stderr, "Error: unknown argument '%s'\n", errstr);
 204         else
 205                 fprintf(stderr, "Error: %s\n", errstr);
 206         fprintf(stderr, "%s\n", helpstring);
 207         return 1;
 208 }
 209
 210 static int err_str0(const char *str0)
 211 {
 212         fprintf(stderr, "%s\n", str0);
 213         return 1;
 214 }
 215
 216 static int err_str1(const char *fmt, const char *str1)
 217 {
 218         fprintf(stderr, fmt, str1);
 219         fprintf(stderr, "\n");
 220         return 1;
 221 }
 222
 223 static int parse_max_tunnels(const char *s, unsigned int *maxtunnels)
 224 {
 225         unsigned long l;
 226         if(!int_strtoul(s, &l) || (l < 1) || (l > 1024)) {
 227                 fprintf(stderr, "Error, '%s' is an invalid value for "
 228                                 "maxtunnels\n", s);
 229                 return 0;
 230         }
 231         *maxtunnels = (unsigned int)l;
 232         return 1;
 233 }
 234
 235 static int parse_server_mode(const char *s, int *servermode)
 236 {
 237         unsigned long l;
 238         if(!int_strtoul(s, &l) || (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         if(!int_strtoul(s, &l) || (l > 3)) {
 262                 fprintf(stderr, "Error, '%s' is an invalid value for "
 263                                 "out_verify\n", s);
 264                 return 0;
 265         }
 266         *verify_level = (unsigned int)l;
 267         return 1;
 268 }
 269
 270 static int parse_verify_depth(const char *s, unsigned int *verify_depth)
 271 {
 272         unsigned long l;
 273         if(!int_strtoul(s, &l) || (l < 1) || (l > 50)) {
 274                 fprintf(stderr, "Error, '%s' is an invalid value for "
 275                                 "verify_depth\n", s);
 276                 return 0;
 277         }
 278         *verify_depth = (unsigned int)l;
 279         return 1;
 280 }
 281
 282 /* Some fprintf format strings used when tunnels close */
 283 static const char *io_stats_dirty =
 284 "    SSL traffic;   %8lu bytes in, %8lu bytes out\n";
 285 static const char *io_stats_clean =
 286 "    clear traffic; %8lu bytes in, %8lu bytes out\n";
 287
 288 int main(int argc, char *argv[])
 289 {
 290         unsigned int loop;
 291         int newfd;
 292         tunala_world_t world;
 293         tunala_item_t *t_item;
 294         const char *proxy_ip;
 295         unsigned short proxy_port;
 296         /* Overridables */
 297         const char *proxyhost = def_proxyhost;
 298         const char *listenhost = def_listenhost;
 299         unsigned int max_tunnels = def_max_tunnels;
 300         const char *cacert = def_cacert;
 301         const char *cert = def_cert;
 302         const char *key = def_key;
 303         const char *dcert = def_dcert;
 304         const char *dkey = def_dkey;
 305         const char *engine_id = def_engine_id;
 306         int server_mode = def_server_mode;
 307         int flipped = def_flipped;
 308         const char *cipher_list = def_cipher_list;
 309         const char *dh_file = def_dh_file;
 310         const char *dh_special = def_dh_special;
 311         int tmp_rsa = def_tmp_rsa;
 312         int ctx_options = def_ctx_options;
 313         int verify_mode = def_verify_mode;
 314         unsigned int verify_depth = def_verify_depth;
 315         int out_state = def_out_state;
 316         unsigned int out_verify = def_out_verify;
 317         int out_totals = def_out_totals;
 318         int out_conns = def_out_conns;
 319
 320 /* Parse command-line arguments */
 321 next_arg:
 322         argc--; argv++;
 323         if(argc > 0) {
 324                 if(strcmp(*argv, "-listen") == 0) {
 325                         if(argc < 2)
 326                                 return usage("-listen requires an argument", 0);
 327                         argc--; argv++;
 328                         listenhost = *argv;
 329                         goto next_arg;
 330                 } else if(strcmp(*argv, "-proxy") == 0) {
 331                         if(argc < 2)
 332                                 return usage("-proxy requires an argument", 0);
 333                         argc--; argv++;
 334                         proxyhost = *argv;
 335                         goto next_arg;
 336                 } else if(strcmp(*argv, "-maxtunnels") == 0) {
 337                         if(argc < 2)
 338                                 return usage("-maxtunnels requires an argument", 0);
 339                         argc--; argv++;
 340                         if(!parse_max_tunnels(*argv, &max_tunnels))
 341                                 return 1;
 342                         goto next_arg;
 343                 } else if(strcmp(*argv, "-cacert") == 0) {
 344                         if(argc < 2)
 345                                 return usage("-cacert requires an argument", 0);
 346                         argc--; argv++;
 347                         if(strcmp(*argv, "NULL") == 0)
 348                                 cacert = NULL;
 349                         else
 350                                 cacert = *argv;
 351                         goto next_arg;
 352                 } else if(strcmp(*argv, "-cert") == 0) {
 353                         if(argc < 2)
 354                                 return usage("-cert requires an argument", 0);
 355                         argc--; argv++;
 356                         if(strcmp(*argv, "NULL") == 0)
 357                                 cert = NULL;
 358                         else
 359                                 cert = *argv;
 360                         goto next_arg;
 361                 } else if(strcmp(*argv, "-key") == 0) {
 362                         if(argc < 2)
 363                                 return usage("-key requires an argument", 0);
 364                         argc--; argv++;
 365                         if(strcmp(*argv, "NULL") == 0)
 366                                 key = NULL;
 367                         else
 368                                 key = *argv;
 369                         goto next_arg;
 370                 } else if(strcmp(*argv, "-dcert") == 0) {
 371                         if(argc < 2)
 372                                 return usage("-dcert requires an argument", 0);
 373                         argc--; argv++;
 374                         if(strcmp(*argv, "NULL") == 0)
 375                                 dcert = NULL;
 376                         else
 377                                 dcert = *argv;
 378                         goto next_arg;
 379                 } else if(strcmp(*argv, "-dkey") == 0) {
 380                         if(argc < 2)
 381                                 return usage("-dkey requires an argument", 0);
 382                         argc--; argv++;
 383                         if(strcmp(*argv, "NULL") == 0)
 384                                 dkey = NULL;
 385                         else
 386                                 dkey = *argv;
 387                         goto next_arg;
 388                 } else if(strcmp(*argv, "-engine") == 0) {
 389                         if(argc < 2)
 390                                 return usage("-engine requires an argument", 0);
 391                         argc--; argv++;
 392                         engine_id = *argv;
 393                         goto next_arg;
 394                 } else if(strcmp(*argv, "-server") == 0) {
 395                         if(argc < 2)
 396                                 return usage("-server requires an argument", 0);
 397                         argc--; argv++;
 398                         if(!parse_server_mode(*argv, &server_mode))
 399                                 return 1;
 400                         goto next_arg;
 401                 } else if(strcmp(*argv, "-flipped") == 0) {
 402                         if(argc < 2)
 403                                 return usage("-flipped requires an argument", 0);
 404                         argc--; argv++;
 405                         if(!parse_server_mode(*argv, &flipped))
 406                                 return 1;
 407                         goto next_arg;
 408                 } else if(strcmp(*argv, "-cipher") == 0) {
 409                         if(argc < 2)
 410                                 return usage("-cipher requires an argument", 0);
 411                         argc--; argv++;
 412                         cipher_list = *argv;
 413                         goto next_arg;
 414                 } else if(strcmp(*argv, "-dh_file") == 0) {
 415                         if(argc < 2)
 416                                 return usage("-dh_file requires an argument", 0);
 417                         if(dh_special)
 418                                 return usage("cannot mix -dh_file with "
 419                                                 "-dh_special", 0);
 420                         argc--; argv++;
 421                         dh_file = *argv;
 422                         goto next_arg;
 423                 } else if(strcmp(*argv, "-dh_special") == 0) {
 424                         if(argc < 2)
 425                                 return usage("-dh_special requires an argument", 0);
 426                         if(dh_file)
 427                                 return usage("cannot mix -dh_file with "
 428                                                 "-dh_special", 0);
 429                         argc--; argv++;
 430                         if(!parse_dh_special(*argv, &dh_special))
 431                                 return 1;
 432                         goto next_arg;
 433                 } else if(strcmp(*argv, "-no_tmp_rsa") == 0) {
 434                         tmp_rsa = 0;
 435                         goto next_arg;
 436                 } else if(strcmp(*argv, "-no_ssl2") == 0) {
 437                         ctx_options |= SSL_OP_NO_SSLv2;
 438                         goto next_arg;
 439                 } else if(strcmp(*argv, "-no_ssl3") == 0) {
 440                         ctx_options |= SSL_OP_NO_SSLv3;
 441                         goto next_arg;
 442                 } else if(strcmp(*argv, "-no_tls1") == 0) {
 443                         ctx_options |= SSL_OP_NO_TLSv1;
 444                         goto next_arg;
 445                 } else if(strcmp(*argv, "-v_peer") == 0) {
 446                         verify_mode |= SSL_VERIFY_PEER;
 447                         goto next_arg;
 448                 } else if(strcmp(*argv, "-v_strict") == 0) {
 449                         verify_mode |= SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
 450                         goto next_arg;
 451                 } else if(strcmp(*argv, "-v_once") == 0) {
 452                         verify_mode |= SSL_VERIFY_CLIENT_ONCE;
 453                         goto next_arg;
 454                 } else if(strcmp(*argv, "-v_depth") == 0) {
 455                         if(argc < 2)
 456                                 return usage("-v_depth requires an argument", 0);
 457                         argc--; argv++;
 458                         if(!parse_verify_depth(*argv, &verify_depth))
 459                                 return 1;
 460                         goto next_arg;
 461                 } else if(strcmp(*argv, "-out_state") == 0) {
 462                         out_state = 1;
 463                         goto next_arg;
 464                 } else if(strcmp(*argv, "-out_verify") == 0) {
 465                         if(argc < 2)
 466                                 return usage("-out_verify requires an argument", 0);
 467                         argc--; argv++;
 468                         if(!parse_verify_level(*argv, &out_verify))
 469                                 return 1;
 470                         goto next_arg;
 471                 } else if(strcmp(*argv, "-out_totals") == 0) {
 472                         out_totals = 1;
 473                         goto next_arg;
 474                 } else if(strcmp(*argv, "-out_conns") == 0) {
 475                         out_conns = 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         /* Run any sanity checks we want here */
 486         if(!cert && !dcert && server_mode)
 487                 fprintf(stderr, "WARNING: you are running an SSL server without "
 488                                 "a certificate - this may not work!\n");
 489
 490         /* Initialise network stuff */
 491         if(!ip_initialise())
 492                 return err_str0("ip_initialise failed");
 493         /* Create the SSL_CTX */
 494         if((world.ssl_ctx = initialise_ssl_ctx(server_mode, engine_id,
 495                         cacert, cert, key, dcert, dkey, cipher_list, dh_file,
 496                         dh_special, tmp_rsa, ctx_options, out_state, out_verify,
 497                         verify_mode, verify_depth)) == NULL)
 498                 return err_str1("initialise_ssl_ctx(engine_id=%s) failed",
 499                         (engine_id == NULL) ? "NULL" : engine_id);
 500         if(engine_id)
 501                 fprintf(stderr, "Info, engine '%s' initialised\n", engine_id);
 502         /* Create the listener */
 503         if((world.listen_fd = ip_create_listener(listenhost)) == -1)
 504                 return err_str1("ip_create_listener(%s) failed", listenhost);
 505         fprintf(stderr, "Info, listening on '%s'\n", listenhost);
 506         if(!ip_parse_address(proxyhost, &proxy_ip, &proxy_port, 0))
 507                 return err_str1("ip_parse_address(%s) failed", proxyhost);
 508         fprintf(stderr, "Info, proxying to '%s' (%d.%d.%d.%d:%d)\n", proxyhost,
 509                         (int)proxy_ip[0], (int)proxy_ip[1],
 510                         (int)proxy_ip[2], (int)proxy_ip[3], (int)proxy_port);
 511         fprintf(stderr, "Info, set maxtunnels to %d\n", (int)max_tunnels);
 512         fprintf(stderr, "Info, set to operate as an SSL %s\n",
 513                         (server_mode ? "server" : "client"));
 514         /* Initialise the rest of the stuff */
 515         world.tunnels_used = world.tunnels_size = 0;
 516         world.tunnels = NULL;
 517         world.server_mode = server_mode;
 518         selector_init(&world.selector);
 519
 520 /* We're ready to loop */
 521 main_loop:
 522         /* Should we listen for *new* tunnels? */
 523         if(world.tunnels_used < max_tunnels)
 524                 selector_add_listener(&world.selector, world.listen_fd);
 525         /* We should add in our existing tunnels */
 526         for(loop = 0; loop < world.tunnels_used; loop++)
 527                 selector_add_tunala(&world.selector, world.tunnels + loop);
 528         /* Now do the select */
 529         switch(selector_select(&world.selector)) {
 530         case -1:
 531                 if(errno != EINTR) {
 532                         fprintf(stderr, "selector_select returned a "
 533                                         "badness error.\n");
 534                         goto shouldnt_happen;
 535                 }
 536                 fprintf(stderr, "Warn, selector interrupted by a signal\n");
 537                 goto main_loop;
 538         case 0:
 539                 fprintf(stderr, "Warn, selector_select returned 0 - signal?""?\n");
 540                 goto main_loop;
 541         default:
 542                 break;
 543         }
 544         /* Accept new connection if we should and can */
 545         if((world.tunnels_used < max_tunnels) && (selector_get_listener(
 546                                         &world.selector, world.listen_fd,
 547                                         &newfd) == 1)) {
 548                 /* We have a new connection */
 549                 if(!tunala_world_new_item(&world, newfd, proxy_ip,
 550                                                 proxy_port, flipped))
 551                         fprintf(stderr, "tunala_world_new_item failed\n");
 552                 else if(out_conns)
 553                         fprintf(stderr, "Info, new tunnel opened, now up to "
 554                                         "%d\n", world.tunnels_used);
 555         }
 556         /* Give each tunnel its moment, note the while loop is because it makes
 557          * the logic easier than with "for" to deal with an array that may shift
 558          * because of deletes. */
 559         loop = 0;
 560         t_item = world.tunnels;
 561         while(loop < world.tunnels_used) {
 562                 if(!tunala_item_io(&world.selector, t_item)) {
 563                         /* We're closing whether for reasons of an error or a
 564                          * natural close. Don't increment loop or t_item because
 565                          * the next item is moving to us! */
 566                         if(!out_totals)
 567                                 goto skip_totals;
 568                         fprintf(stderr, "Tunnel closing, traffic stats follow\n");
 569                         /* Display the encrypted (over the network) stats */
 570                         fprintf(stderr, io_stats_dirty,
 571                                 buffer_total_in(state_machine_get_buffer(
 572                                                 &t_item->sm,SM_DIRTY_IN)),
 573                                 buffer_total_out(state_machine_get_buffer(
 574                                                 &t_item->sm,SM_DIRTY_OUT)));
 575                         /* Display the local (tunnelled) stats. NB: Data we
 576                          * *receive* is data sent *out* of the state_machine on
 577                          * its 'clean' side. Hence the apparent back-to-front
 578                          * OUT/IN mixup here :-) */
 579                         fprintf(stderr, io_stats_clean,
 580                                 buffer_total_out(state_machine_get_buffer(
 581                                                 &t_item->sm,SM_CLEAN_OUT)),
 582                                 buffer_total_in(state_machine_get_buffer(
 583                                                 &t_item->sm,SM_CLEAN_IN)));
 584 skip_totals:
 585                         tunala_world_del_item(&world, loop);
 586                         if(out_conns)
 587                                 fprintf(stderr, "Info, tunnel closed, down to %d\n",
 588                                         world.tunnels_used);
 589                 }
 590                 else {
 591                         /* Move to the next item */
 592                         loop++;
 593                         t_item++;
 594                 }
 595         }
 596         goto main_loop;
 597         /* Should never get here */
 598 shouldnt_happen:
 599         abort();
 600         return 1;
 601 }
 602
 603 /****************/
 604 /* OpenSSL bits */
 605 /****************/
 606
 607 static int ctx_set_cert(SSL_CTX *ctx, const char *cert, const char *key)
 608 {
 609         FILE *fp = NULL;
 610         X509 *x509 = NULL;
 611         EVP_PKEY *pkey = NULL;
 612         int toret = 0; /* Assume an error */
 613
 614         /* cert */
 615         if(cert) {
 616                 if((fp = fopen(cert, "r")) == NULL) {
 617                         fprintf(stderr, "Error opening cert file '%s'\n", cert);
 618                         goto err;
 619                 }
 620                 if(!PEM_read_X509(fp, &x509, NULL, NULL)) {
 621                         fprintf(stderr, "Error reading PEM cert from '%s'\n",
 622                                         cert);
 623                         goto err;
 624                 }
 625                 if(!SSL_CTX_use_certificate(ctx, x509)) {
 626                         fprintf(stderr, "Error, cert in '%s' can not be used\n",
 627                                         cert);
 628                         goto err;
 629                 }
 630                 /* Clear the FILE* for reuse in the "key" code */
 631                 fclose(fp);
 632                 fp = NULL;
 633                 fprintf(stderr, "Info, operating with cert in '%s'\n", cert);
 634                 /* If a cert was given without matching key, we assume the same
 635                  * file contains the required key. */
 636                 if(!key)
 637                         key = cert;
 638         } else {
 639                 if(key)
 640                         fprintf(stderr, "Error, can't specify a key without a "
 641                                         "corresponding certificate\n");
 642                 else
 643                         fprintf(stderr, "Error, ctx_set_cert called with "
 644                                         "NULLs!\n");
 645                 goto err;
 646         }
 647         /* key */
 648         if(key) {
 649                 if((fp = fopen(key, "r")) == NULL) {
 650                         fprintf(stderr, "Error opening key file '%s'\n", key);
 651                         goto err;
 652                 }
 653                 if(!PEM_read_PrivateKey(fp, &pkey, NULL, NULL)) {
 654                         fprintf(stderr, "Error reading PEM key from '%s'\n",
 655                                         key);
 656                         goto err;
 657                 }
 658                 if(!SSL_CTX_use_PrivateKey(ctx, pkey)) {
 659                         fprintf(stderr, "Error, key in '%s' can not be used\n",
 660                                         key);
 661                         goto err;
 662                 }
 663                 fprintf(stderr, "Info, operating with key in '%s'\n", key);
 664         } else
 665                 fprintf(stderr, "Info, operating without a cert or key\n");
 666         /* Success */
 667         toret = 1; err:
 668         if(x509)
 669                 X509_free(x509);
 670         if(pkey)
 671                 EVP_PKEY_free(pkey);
 672         if(fp)
 673                 fclose(fp);
 674         return toret;
 675 }
 676
 677 static int ctx_set_dh(SSL_CTX *ctx, const char *dh_file, const char *dh_special)
 678 {
 679         DH *dh = NULL;
 680         FILE *fp = NULL;
 681
 682         if(dh_special) {
 683                 if(strcmp(dh_special, "NULL") == 0)
 684                         return 1;
 685                 if(strcmp(dh_special, "standard") == 0) {
 686                         if((dh = get_dh512()) == NULL) {
 687                                 fprintf(stderr, "Error, can't parse 'standard'"
 688                                                 " DH parameters\n");
 689                                 return 0;
 690                         }
 691                         fprintf(stderr, "Info, using 'standard' DH parameters\n");
 692                         goto do_it;
 693                 }
 694                 if(strcmp(dh_special, "generate") != 0)
 695                         /* This shouldn't happen - screening values is handled
 696                          * in main(). */
 697                         abort();
 698                 fprintf(stderr, "Info, generating DH parameters ... ");
 699                 fflush(stderr);
 700                 if(!(dh = DH_new()) || !DH_generate_parameters_ex(dh, 512,
 701                                         DH_GENERATOR_5, NULL)) {
 702                         fprintf(stderr, "error!\n");
 703                         if(dh)
 704                                 DH_free(dh);
 705                         return 0;
 706                 }
 707                 fprintf(stderr, "complete\n");
 708                 goto do_it;
 709         }
 710         /* So, we're loading dh_file */
 711         if((fp = fopen(dh_file, "r")) == NULL) {
 712                 fprintf(stderr, "Error, couldn't open '%s' for DH parameters\n",
 713                                 dh_file);
 714                 return 0;
 715         }
 716         dh = PEM_read_DHparams(fp, NULL, NULL, NULL);
 717         fclose(fp);
 718         if(dh == NULL) {
 719                 fprintf(stderr, "Error, could not parse DH parameters from '%s'\n",
 720                                 dh_file);
 721                 return 0;
 722         }
 723         fprintf(stderr, "Info, using DH parameters from file '%s'\n", dh_file);
 724 do_it:
 725         SSL_CTX_set_tmp_dh(ctx, dh);
 726         DH_free(dh);
 727         return 1;
 728 }
 729
 730 static SSL_CTX *initialise_ssl_ctx(int server_mode, const char *engine_id,
 731                 const char *CAfile, const char *cert, const char *key,
 732                 const char *dcert, const char *dkey, const char *cipher_list,
 733                 const char *dh_file, const char *dh_special, int tmp_rsa,
 734                 int ctx_options, int out_state, int out_verify, int verify_mode,
 735                 unsigned int verify_depth)
 736 {
 737         SSL_CTX *ctx = NULL, *ret = NULL;
 738         const SSL_METHOD *meth;
 739         ENGINE *e = NULL;
 740
 741         OpenSSL_add_ssl_algorithms();
 742         SSL_load_error_strings();
 743
 744         meth = (server_mode ? SSLv23_server_method() : SSLv23_client_method());
 745         if(meth == NULL)
 746                 goto err;
 747         if(engine_id) {
 748                 ENGINE_load_builtin_engines();
 749                 if((e = ENGINE_by_id(engine_id)) == NULL) {
 750                         fprintf(stderr, "Error obtaining '%s' engine, openssl "
 751                                         "errors follow\n", engine_id);
 752                         goto err;
 753                 }
 754                 if(!ENGINE_set_default(e, ENGINE_METHOD_ALL)) {
 755                         fprintf(stderr, "Error assigning '%s' engine, openssl "
 756                                         "errors follow\n", engine_id);
 757                         goto err;
 758                 }
 759                 ENGINE_free(e);
 760         }
 761         if((ctx = SSL_CTX_new(meth)) == NULL)
 762                 goto err;
 763         /* cacert */
 764         if(CAfile) {
 765                 if(!X509_STORE_load_locations(SSL_CTX_get_cert_store(ctx),
 766                                         CAfile, NULL)) {
 767                         fprintf(stderr, "Error loading CA cert(s) in '%s'\n",
 768                                         CAfile);
 769                         goto err;
 770                 }
 771                 fprintf(stderr, "Info, operating with CA cert(s) in '%s'\n",
 772                                 CAfile);
 773         } else
 774                 fprintf(stderr, "Info, operating without a CA cert(-list)\n");
 775         if(!SSL_CTX_set_default_verify_paths(ctx)) {
 776                 fprintf(stderr, "Error setting default verify paths\n");
 777                 goto err;
 778         }
 779
 780         /* cert and key */
 781         if((cert || key) && !ctx_set_cert(ctx, cert, key))
 782                 goto err;
 783         /* dcert and dkey */
 784         if((dcert || dkey) && !ctx_set_cert(ctx, dcert, dkey))
 785                 goto err;
 786         /* temporary RSA key generation */
 787         if(tmp_rsa)
 788                 SSL_CTX_set_tmp_rsa_callback(ctx, cb_generate_tmp_rsa);
 789
 790         /* cipher_list */
 791         if(cipher_list) {
 792                 if(!SSL_CTX_set_cipher_list(ctx, cipher_list)) {
 793                         fprintf(stderr, "Error setting cipher list '%s'\n",
 794                                         cipher_list);
 795                         goto err;
 796                 }
 797                 fprintf(stderr, "Info, set cipher list '%s'\n", cipher_list);
 798         } else
 799                 fprintf(stderr, "Info, operating with default cipher list\n");
 800
 801         /* dh_file & dh_special */
 802         if((dh_file || dh_special) && !ctx_set_dh(ctx, dh_file, dh_special))
 803                 goto err;
 804
 805         /* ctx_options */
 806         SSL_CTX_set_options(ctx, ctx_options);
 807
 808         /* out_state (output of SSL handshake states to screen). */
 809         if(out_state)
 810                 cb_ssl_info_set_output(stderr);
 811
 812         /* out_verify */
 813         if(out_verify > 0) {
 814                 cb_ssl_verify_set_output(stderr);
 815                 cb_ssl_verify_set_level(out_verify);
 816         }
 817
 818         /* verify_depth */
 819         cb_ssl_verify_set_depth(verify_depth);
 820
 821         /* Success! (includes setting verify_mode) */
 822         SSL_CTX_set_info_callback(ctx, cb_ssl_info);
 823         SSL_CTX_set_verify(ctx, verify_mode, cb_ssl_verify);
 824         ret = ctx;
 825 err:
 826         if(!ret) {
 827                 ERR_print_errors_fp(stderr);
 828                 if(ctx)
 829                         SSL_CTX_free(ctx);
 830         }
 831         return ret;
 832 }
 833
 834 /*****************/
 835 /* Selector bits */
 836 /*****************/
 837
 838 static void selector_sets_init(select_sets_t *s)
 839 {
 840         s->max = 0;
 841         FD_ZERO(&s->reads);
 842         FD_ZERO(&s->sends);
 843         FD_ZERO(&s->excepts);
 844 }
 845 static void selector_init(tunala_selector_t *selector)
 846 {
 847         selector_sets_init(&selector->last_selected);
 848         selector_sets_init(&selector->next_select);
 849 }
 850
 851 #define SEL_EXCEPTS 0x00
 852 #define SEL_READS   0x01
 853 #define SEL_SENDS   0x02
 854 static void selector_add_raw_fd(tunala_selector_t *s, int fd, int flags)
 855 {
 856         FD_SET(fd, &s->next_select.excepts);
 857         if(flags & SEL_READS)
 858                 FD_SET(fd, &s->next_select.reads);
 859         if(flags & SEL_SENDS)
 860                 FD_SET(fd, &s->next_select.sends);
 861         /* Adjust "max" */
 862         if(s->next_select.max < (fd + 1))
 863                 s->next_select.max = fd + 1;
 864 }
 865
 866 static void selector_add_listener(tunala_selector_t *selector, int fd)
 867 {
 868         selector_add_raw_fd(selector, fd, SEL_READS);
 869 }
 870
 871 static void selector_add_tunala(tunala_selector_t *s, tunala_item_t *t)
 872 {
 873         /* Set clean read if sm.clean_in is not full */
 874         if(t->clean_read != -1) {
 875                 selector_add_raw_fd(s, t->clean_read,
 876                         (buffer_full(state_machine_get_buffer(&t->sm,
 877                                 SM_CLEAN_IN)) ? SEL_EXCEPTS : SEL_READS));
 878         }
 879         /* Set clean send if sm.clean_out is not empty */
 880         if(t->clean_send != -1) {
 881                 selector_add_raw_fd(s, t->clean_send,
 882                         (buffer_empty(state_machine_get_buffer(&t->sm,
 883                                 SM_CLEAN_OUT)) ? SEL_EXCEPTS : SEL_SENDS));
 884         }
 885         /* Set dirty read if sm.dirty_in is not full */
 886         if(t->dirty_read != -1) {
 887                 selector_add_raw_fd(s, t->dirty_read,
 888                         (buffer_full(state_machine_get_buffer(&t->sm,
 889                                 SM_DIRTY_IN)) ? SEL_EXCEPTS : SEL_READS));
 890         }
 891         /* Set dirty send if sm.dirty_out is not empty */
 892         if(t->dirty_send != -1) {
 893                 selector_add_raw_fd(s, t->dirty_send,
 894                         (buffer_empty(state_machine_get_buffer(&t->sm,
 895                                 SM_DIRTY_OUT)) ? SEL_EXCEPTS : SEL_SENDS));
 896         }
 897 }
 898
 899 static int selector_select(tunala_selector_t *selector)
 900 {
 901         memcpy(&selector->last_selected, &selector->next_select,
 902                         sizeof(select_sets_t));
 903         selector_sets_init(&selector->next_select);
 904         return select(selector->last_selected.max,
 905                         &selector->last_selected.reads,
 906                         &selector->last_selected.sends,
 907                         &selector->last_selected.excepts, NULL);
 908 }
 909
 910 /* This returns -1 for error, 0 for no new connections, or 1 for success, in
 911  * which case *newfd is populated. */
 912 static int selector_get_listener(tunala_selector_t *selector, int fd, int *newfd)
 913 {
 914         if(FD_ISSET(fd, &selector->last_selected.excepts))
 915                 return -1;
 916         if(!FD_ISSET(fd, &selector->last_selected.reads))
 917                 return 0;
 918         if((*newfd = ip_accept_connection(fd)) == -1)
 919                 return -1;
 920         return 1;
 921 }
 922
 923 /************************/
 924 /* "Tunala" world stuff */
 925 /************************/
 926
 927 static int tunala_world_make_room(tunala_world_t *world)
 928 {
 929         unsigned int newsize;
 930         tunala_item_t *newarray;
 931
 932         if(world->tunnels_used < world->tunnels_size)
 933                 return 1;
 934         newsize = (world->tunnels_size == 0 ? 16 :
 935                         ((world->tunnels_size * 3) / 2));
 936         if((newarray = malloc(newsize * sizeof(tunala_item_t))) == NULL)
 937                 return 0;
 938         memset(newarray, 0, newsize * sizeof(tunala_item_t));
 939         if(world->tunnels_used > 0)
 940                 memcpy(newarray, world->tunnels,
 941                         world->tunnels_used * sizeof(tunala_item_t));
 942         if(world->tunnels_size > 0)
 943                 free(world->tunnels);
 944         /* migrate */
 945         world->tunnels = newarray;
 946         world->tunnels_size = newsize;
 947         return 1;
 948 }
 949
 950 static int tunala_world_new_item(tunala_world_t *world, int fd,
 951                 const char *ip, unsigned short port, int flipped)
 952 {
 953         tunala_item_t *item;
 954         int newfd;
 955         SSL *new_ssl = NULL;
 956
 957         if(!tunala_world_make_room(world))
 958                 return 0;
 959         if((new_ssl = SSL_new(world->ssl_ctx)) == NULL) {
 960                 fprintf(stderr, "Error creating new SSL\n");
 961                 ERR_print_errors_fp(stderr);
 962                 return 0;
 963         }
 964         item = world->tunnels + (world->tunnels_used++);
 965         state_machine_init(&item->sm);
 966         item->clean_read = item->clean_send =
 967                 item->dirty_read = item->dirty_send = -1;
 968         if((newfd = ip_create_connection_split(ip, port)) == -1)
 969                 goto err;
 970         /* Which way round? If we're a server, "fd" is the dirty side and the
 971          * connection we open is the clean one. For a client, it's the other way
 972          * around. Unless, of course, we're "flipped" in which case everything
 973          * gets reversed. :-) */
 974         if((world->server_mode && !flipped) ||
 975                         (!world->server_mode && flipped)) {
 976                 item->dirty_read = item->dirty_send = fd;
 977                 item->clean_read = item->clean_send = newfd;
 978         } else {
 979                 item->clean_read = item->clean_send = fd;
 980                 item->dirty_read = item->dirty_send = newfd;
 981         }
 982         /* We use the SSL's "app_data" to indicate a call-back induced "kill" */
 983         SSL_set_app_data(new_ssl, NULL);
 984         if(!state_machine_set_SSL(&item->sm, new_ssl, world->server_mode))
 985                 goto err;
 986         return 1;
 987 err:
 988         tunala_world_del_item(world, world->tunnels_used - 1);
 989         return 0;
 990
 991 }
 992
 993 static void tunala_world_del_item(tunala_world_t *world, unsigned int idx)
 994 {
 995         tunala_item_t *item = world->tunnels + idx;
 996         if(item->clean_read != -1)
 997                 close(item->clean_read);
 998         if(item->clean_send != item->clean_read)
 999                 close(item->clean_send);
1000         item->clean_read = item->clean_send = -1;
1001         if(item->dirty_read != -1)
1002                 close(item->dirty_read);
1003         if(item->dirty_send != item->dirty_read)
1004                 close(item->dirty_send);
1005         item->dirty_read = item->dirty_send = -1;
1006         state_machine_close(&item->sm);
1007         /* OK, now we fix the item array */
1008         if(idx + 1 < world->tunnels_used)
1009                 /* We need to scroll entries to the left */
1010                 memmove(world->tunnels + idx,
1011                                 world->tunnels + (idx + 1),
1012                                 (world->tunnels_used - (idx + 1)) *
1013                                         sizeof(tunala_item_t));
1014         world->tunnels_used--;
1015 }
1016
1017 static int tunala_item_io(tunala_selector_t *selector, tunala_item_t *item)
1018 {
1019         int c_r, c_s, d_r, d_s; /* Four boolean flags */
1020
1021         /* Take ourselves out of the gene-pool if there was an except */
1022         if((item->clean_read != -1) && FD_ISSET(item->clean_read,
1023                                 &selector->last_selected.excepts))
1024                 return 0;
1025         if((item->clean_send != -1) && FD_ISSET(item->clean_send,
1026                                 &selector->last_selected.excepts))
1027                 return 0;
1028         if((item->dirty_read != -1) && FD_ISSET(item->dirty_read,
1029                                 &selector->last_selected.excepts))
1030                 return 0;
1031         if((item->dirty_send != -1) && FD_ISSET(item->dirty_send,
1032                                 &selector->last_selected.excepts))
1033                 return 0;
1034         /* Grab our 4 IO flags */
1035         c_r = c_s = d_r = d_s = 0;
1036         if(item->clean_read != -1)
1037                 c_r = FD_ISSET(item->clean_read, &selector->last_selected.reads);
1038         if(item->clean_send != -1)
1039                 c_s = FD_ISSET(item->clean_send, &selector->last_selected.sends);
1040         if(item->dirty_read != -1)
1041                 d_r = FD_ISSET(item->dirty_read, &selector->last_selected.reads);
1042         if(item->dirty_send != -1)
1043                 d_s = FD_ISSET(item->dirty_send, &selector->last_selected.sends);
1044         /* If no IO has happened for us, skip needless data looping */
1045         if(!c_r && !c_s && !d_r && !d_s)
1046                 return 1;
1047         if(c_r)
1048                 c_r = (buffer_from_fd(state_machine_get_buffer(&item->sm,
1049                                 SM_CLEAN_IN), item->clean_read) <= 0);
1050         if(c_s)
1051                 c_s = (buffer_to_fd(state_machine_get_buffer(&item->sm,
1052                                 SM_CLEAN_OUT), item->clean_send) <= 0);
1053         if(d_r)
1054                 d_r = (buffer_from_fd(state_machine_get_buffer(&item->sm,
1055                                 SM_DIRTY_IN), item->dirty_read) <= 0);
1056         if(d_s)
1057                 d_s = (buffer_to_fd(state_machine_get_buffer(&item->sm,
1058                                 SM_DIRTY_OUT), item->dirty_send) <= 0);
1059         /* If any of the flags is non-zero, that means they need closing */
1060         if(c_r) {
1061                 close(item->clean_read);
1062                 if(item->clean_send == item->clean_read)
1063                         item->clean_send = -1;
1064                 item->clean_read = -1;
1065         }
1066         if(c_s && (item->clean_send != -1)) {
1067                 close(item->clean_send);
1068                 if(item->clean_send == item->clean_read)
1069                         item->clean_read = -1;
1070                 item->clean_send = -1;
1071         }
1072         if(d_r) {
1073                 close(item->dirty_read);
1074                 if(item->dirty_send == item->dirty_read)
1075                         item->dirty_send = -1;
1076                 item->dirty_read = -1;
1077         }
1078         if(d_s && (item->dirty_send != -1)) {
1079                 close(item->dirty_send);
1080                 if(item->dirty_send == item->dirty_read)
1081                         item->dirty_read = -1;
1082                 item->dirty_send = -1;
1083         }
1084         /* This function name is attributed to the term donated by David
1085          * Schwartz on openssl-dev, message-ID:
1086          * <NCBBLIEPOCNJOAEKBEAKEEDGLIAA.davids@webmaster.com>. :-) */
1087         if(!state_machine_churn(&item->sm))
1088                 /* If the SSL closes, it will also zero-out the _in buffers
1089                  * and will in future process just outgoing data. As and
1090                  * when the outgoing data has gone, it will return zero
1091                  * here to tell us to bail out. */
1092                 return 0;
1093         /* Otherwise, we return zero if both sides are dead. */
1094         if(((item->clean_read == -1) || (item->clean_send == -1)) &&
1095                         ((item->dirty_read == -1) || (item->dirty_send == -1)))
1096                 return 0;
1097         /* If only one side closed, notify the SSL of this so it can take
1098          * appropriate action. */
1099         if((item->clean_read == -1) || (item->clean_send == -1)) {
1100                 if(!state_machine_close_clean(&item->sm))
1101                         return 0;
1102         }
1103         if((item->dirty_read == -1) || (item->dirty_send == -1)) {
1104                 if(!state_machine_close_dirty(&item->sm))
1105                         return 0;
1106         }
1107         return 1;
1108 }
1109