mdw@git.distorted.org.uk Git - tripe/blob - proxy/tripe-mitm.c

   1 /* -*-c-*-
   2  *
   3  * An evil proxy for TrIPE
   4  *
   5  * (c) 2001 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Trivial IP Encryption (TrIPE).
  11  *
  12  * TrIPE is free software: you can redistribute it and/or modify it under
  13  * the terms of the GNU General Public License as published by the Free
  14  * Software Foundation; either version 3 of the License, or (at your
  15  * option) any later version.
  16  *
  17  * TrIPE is distributed in the hope that it will be useful, but WITHOUT
  18  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  19  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  20  * for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with TrIPE.  If not, see <https://www.gnu.org/licenses/>.
  24  */
  25
  26 /*----- Header files ------------------------------------------------------*/
  27
  28 #include "config.h"
  29
  30 #include <assert.h>
  31 #include <errno.h>
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include <time.h>
  36
  37 #include <sys/types.h>
  38 #include <sys/time.h>
  39 #include <unistd.h>
  40 #include <fcntl.h>
  41
  42 #include <sys/socket.h>
  43 #include <netinet/in.h>
  44 #include <arpa/inet.h>
  45 #include <netdb.h>
  46
  47 #include <mLib/alloc.h>
  48 #include <mLib/dstr.h>
  49 #include <mLib/fdflags.h>
  50 #include <mLib/mdwopt.h>
  51 #include <mLib/quis.h>
  52 #include <mLib/report.h>
  53 #include <mLib/sel.h>
  54 #include <mLib/sub.h>
  55 #include <mLib/tv.h>
  56
  57 #include <catacomb/buf.h>
  58
  59 #include <catacomb/key.h>
  60
  61 #include <catacomb/mp.h>
  62 #include <catacomb/mprand.h>
  63 #include <catacomb/dh.h>
  64
  65 #include <catacomb/noise.h>
  66 #include <catacomb/rand.h>
  67 #include <catacomb/rc4.h>
  68
  69 #include "util.h"
  70
  71 /*----- Data structures ---------------------------------------------------*/
  72
  73 typedef struct peer {
  74   sel_file sf;
  75   const char *name;
  76   struct filter *f;
  77 } peer;
  78
  79 typedef struct filter {
  80   struct filter *next;
  81   peer *p_from, *p_to;
  82   void (*func)(struct filter */*f*/, const octet */*buf*/, size_t /*sz*/);
  83   void *state;
  84 } filter;
  85
  86 typedef struct qnode {
  87   octet *buf;
  88   size_t sz;
  89 } qnode;
  90
  91 /*----- Static variables --------------------------------------------------*/
  92
  93 #define PKBUFSZ 65536
  94
  95 static sel_state sel;
  96 static peer peers[2];
  97 static unsigned npeer = 0;
  98 static key_file keys;
  99 static grand *rng;
 100
 101 #define PASS(f, buf, sz) ((f) ? (f)->func((f), (buf), (sz)) : (void)0)
 102 #define RND(i) (rng->ops->range(rng, (i)))
 103
 104 /*----- Peer management ---------------------------------------------------*/
 105
 106 static void dopacket(int fd, unsigned mode, void *vv)
 107 {
 108   octet buf[PKBUFSZ];
 109   peer *p = vv;
 110   int r = read(fd, buf, sizeof(buf));
 111   if (r >= 0) {
 112     printf("recv from `%s'\n", p->name);
 113     PASS(p->f, buf, r);
 114   }
 115 }
 116
 117 static void addpeer(unsigned ac, char **av)
 118 {
 119   struct hostent *h;
 120   struct sockaddr_in sin;
 121   int len = PKBUFSZ;
 122   peer *p;
 123   int fd;
 124
 125   if (ac != 4)
 126     die(1, "syntax: peer:NAME:PORT:ADDR:PORT");
 127   if (npeer >= 2)
 128     die(1, "enough peers already");
 129   if (!key_bytag(&keys, av[0]))
 130     die(1, "no key named `%s'", av[0]);
 131   p = &peers[npeer++];
 132   p->name = xstrdup(av[0]);
 133   if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
 134     die(1, "socket: %s", strerror(errno));
 135   fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 136   memset(&sin, 0, sizeof(sin));
 137   sin.sin_family = AF_INET;
 138   sin.sin_addr.s_addr = INADDR_ANY;
 139   sin.sin_port = htons(atoi(av[1]));
 140   if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)))
 141     die(1, "bind: %s", strerror(errno));
 142   memset(&sin, 0, sizeof(sin));
 143   sin.sin_family = AF_INET;
 144   if ((h = gethostbyname(av[2])) == 0)
 145     die(1, "gethostbyname `%s'", av[2]);
 146   if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
 147       setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len)))
 148     die(1, "setsockopt: %s", strerror(errno));
 149   memcpy(&sin.sin_addr, h->h_addr, sizeof(sin.sin_addr));
 150   sin.sin_port = htons(atoi(av[3]));
 151   if (connect(fd, (struct sockaddr *)&sin, sizeof(sin)))
 152     die(1, "connect: %s", strerror(errno));
 153   sel_initfile(&sel, &p->sf, fd, SEL_READ, dopacket, p);
 154   sel_addfile(&p->sf);
 155 }
 156
 157 /*----- Fork filter -------------------------------------------------------*/
 158
 159 typedef struct forknode {
 160   struct forknode *next;
 161   filter *f;
 162 } forknode;
 163
 164 typedef struct forkfilt {
 165   const char *name;
 166   forknode *fn;
 167 } forkfilt;
 168
 169 static void dofork(filter *f, const octet *buf, size_t sz)
 170 {
 171   forkfilt *ff = f->state;
 172   forknode *fn;
 173   unsigned i = 0;
 174
 175   ff = f->state;
 176   for (fn = ff->fn; fn; fn = fn->next) {
 177     printf("fork branch %u of fork `%s'\n", i++, ff->name);
 178     PASS(fn->f, buf, sz);
 179   }
 180   printf("fork branch %u of fork `%s'\n", i++, ff->name);
 181   PASS(f->next, buf, sz);
 182 }
 183
 184 static void addfork(filter *f, unsigned ac, char **av)
 185 {
 186   forkfilt *ff;
 187   if (ac != 1)
 188     die(1, "syntax: filt:fork:NAME");
 189   ff = CREATE(forkfilt);
 190   ff->name = xstrdup(av[0]);
 191   ff->fn = 0;
 192   f->func = dofork;
 193   f->state = ff;
 194 }
 195
 196 static void nextfork(unsigned ac, char **av)
 197 {
 198   unsigned i, j;
 199   filter *f;
 200   forkfilt *ff;
 201   forknode *fn, **ffn;
 202   peer *p;
 203
 204   if (ac < 1)
 205     die(1, "syntax: next:NAME:...");
 206   for (i = 0; i < 2; i++) {
 207     p = &peers[i];
 208     for (f = p->f; f; f = f->next) {
 209       if (f->func != dofork)
 210         continue;
 211       ff = f->state;
 212       for (j = 0; j < ac; j++) {
 213         if (strcmp(av[j], ff->name) == 0)
 214           goto match;
 215       }
 216       continue;
 217     match:
 218       fn = CREATE(forknode);
 219       for (ffn = &ff->fn; *ffn; ffn = &(*ffn)->next)
 220         ;
 221       fn->f = f->next;
 222       f->next = 0;
 223       fn->next = 0;
 224       *ffn = fn;
 225     }
 226   }
 227 }
 228
 229 /*----- Corrupt filter ----------------------------------------------------*/
 230
 231 typedef struct corrupt {
 232   unsigned p_corrupt;
 233 } corrupt;
 234
 235 static void docorrupt(filter *f, const octet *buf, size_t sz)
 236 {
 237   corrupt *c = f->state;
 238   octet b[PKBUFSZ];
 239   memcpy(b, buf, sz);
 240
 241   while (!RND(c->p_corrupt)) {
 242     puts("corrupt packet");
 243     b[RND(sz)] ^= RND(256);
 244   }
 245   PASS(f->next, b, sz);
 246 }
 247
 248 static void addcorrupt(filter *f, unsigned ac, char **av)
 249 {
 250   corrupt *c;
 251   if (ac > 1)
 252     die(1, "syntax: filt:corrupt[:P-CORRUPT]");
 253   c = CREATE(corrupt);
 254   if (ac > 0)
 255     c->p_corrupt = atoi(av[0]);
 256   else
 257     c->p_corrupt = 5;
 258   f->state = c;
 259   f->func = docorrupt;
 260 }
 261
 262 /*----- Drop filter -------------------------------------------------------*/
 263
 264 typedef struct drop {
 265   unsigned p_drop;
 266 } drop;
 267
 268 static void dodrop(filter *f, const octet *buf, size_t sz)
 269 {
 270   drop *d = f->state;
 271
 272   if (!RND(d->p_drop))
 273     puts("drop packet");
 274   else
 275     PASS(f->next, buf, sz);
 276 }
 277
 278 static void adddrop(filter *f, unsigned ac, char **av)
 279 {
 280   drop *d;
 281   if (ac > 1)
 282     die(1, "syntax: filt:drop[:P-DROP]");
 283   d = CREATE(drop);
 284   if (ac > 0)
 285     d->p_drop = atoi(av[0]);
 286   else
 287     d->p_drop = 5;
 288   f->state = d;
 289   f->func = dodrop;
 290 }
 291
 292 /*----- Delay filter ------------------------------------------------------*/
 293
 294 typedef struct delaynode {
 295   unsigned flag;
 296   sel_timer tm;
 297   unsigned i;
 298   struct delay *d;
 299   octet *buf;
 300   size_t sz;
 301   unsigned seq;
 302 } delaynode;
 303
 304 typedef struct delay {
 305   unsigned max, n;
 306   unsigned long t;
 307   unsigned p_replay;
 308   filter *f;
 309   delaynode *q;
 310 } delay;
 311
 312 static void dtimer(struct timeval *tv, void *vv);
 313
 314 static void dinsert(delaynode *dn)
 315 {
 316   struct timeval tv;
 317   sel_timer *ta, *tb;
 318   unsigned long tdelta = RND(dn->d->t);
 319   gettimeofday(&tv, 0);
 320   TV_ADDL(&tv, &tv, 0, tdelta);
 321   assert(!dn->flag);
 322   sel_addtimer(&sel, &dn->tm, &tv, dtimer, dn);
 323   dn->flag = 1;
 324   for (ta = tb = sel.timers; ta; ta = ta->next) {
 325     ta = ta->next; if (!ta) break; assert(ta != tb);
 326     ta = ta->next; if (!ta) break; assert(ta != tb);
 327     tb = tb->next;
 328   }
 329   printf(" delay %lu usecs", tdelta);
 330 }
 331
 332 static void dsend(delaynode *dn, unsigned force)
 333 {
 334   delay *d = dn->d;
 335   delaynode *ddn;
 336   fputs(" send...\n", stdout);
 337   assert(dn->buf);
 338   PASS(d->f->next, dn->buf, dn->sz);
 339   fputs("delay ...", stdout);
 340   if (!force)
 341     dinsert(dn);
 342   else {
 343     xfree(dn->buf);
 344     dn->buf = 0;
 345     d->n--;
 346     if (dn->i < d->n) {
 347       ddn = &d->q[d->n];
 348       sel_rmtimer(&ddn->tm);
 349       sel_addtimer(&sel, &dn->tm, &ddn->tm.tv, dtimer, dn);
 350       dn->flag = 1;
 351       dn->buf = ddn->buf;
 352       dn->sz = ddn->sz;
 353       dn->seq = ddn->seq;
 354       ddn->buf = 0;
 355       ddn->flag = 0;
 356       printf(" move id %u from slot %u to slot %u", ddn->seq, ddn->i, dn->i);
 357     }
 358     { unsigned i; for (i = 0; i < d->n; i++) assert(d->q[i].buf); }
 359     fputs(" remove", stdout);
 360   }
 361 }
 362
 363 static void dtimer(struct timeval *tv, void *vv)
 364 {
 365   delaynode *dn = vv;
 366   printf("delay timer peer `%s' id %u slot %u",
 367          dn->d->f->p_from->name, dn->seq, dn->i);
 368   dn->flag = 0;
 369   dsend(dn, RND(dn->d->p_replay));
 370   fputc('\n', stdout);
 371 }
 372
 373 static void dodelay(filter *f, const octet *buf, size_t sz)
 374 {
 375   delay *d = f->state;
 376   delaynode *dn;
 377   static unsigned seq = 0;
 378
 379   fputs("delay", stdout);
 380   if (d->n == d->max) {
 381     dn = &d->q[RND(d->n)];
 382     printf(" force uid %u", dn->seq);
 383     sel_rmtimer(&dn->tm);
 384     dn->flag = 0;
 385     dsend(dn, 1);
 386     fputc(';', stdout);
 387   }
 388   dn = &d->q[d->n++];
 389   dn->seq = seq++;
 390   printf(" new id %u in slot %u", dn->seq, dn->i);
 391   dn->buf = xmalloc(sz);
 392   dn->sz = sz;
 393   memcpy(dn->buf, buf, sz);
 394   dinsert(dn);
 395   fputc('\n', stdout);
 396 }
 397
 398 static void adddelay(filter *f, unsigned ac, char **av)
 399 {
 400   delay *d;
 401   unsigned i;
 402
 403   if (ac < 1 || ac > 3)
 404     die(1, "syntax: filt:delay:QLEN[:MILLIS:P-REPLAY]");
 405   d = CREATE(delay);
 406   d->max = atoi(av[0]);
 407   if (ac > 1)
 408     d->t = strtoul(av[1], 0, 10);
 409   else
 410     d->t = 100;
 411   d->t *= 1000;
 412   if (ac > 2)
 413     d->p_replay = atoi(av[2]);
 414   else
 415     d->p_replay = 20;
 416   d->n = 0;
 417   d->q = xmalloc(d->max * sizeof(delaynode));
 418   d->f = f;
 419   f->state = d;
 420   f->func = dodelay;
 421   for (i = 0; i < d->max; i++) {
 422     d->q[i].d = d;
 423     d->q[i].i = i;
 424     d->q[i].buf = 0;
 425     d->q[i].flag = 0;
 426   }
 427 }
 428
 429 /*----- Filters -----------------------------------------------------------*/
 430
 431 static void dosend(filter *f, const octet *buf, size_t sz)
 432 {
 433   printf("send to `%s'\n", f->p_to->name);
 434   DISCARD(write(f->p_to->sf.fd, buf, sz));
 435 }
 436
 437 static void addsend(filter *f, unsigned ac, char **av)
 438 {
 439   if (ac)
 440     die(1, "syntax: filt:send");
 441   f->func = dosend;
 442 }
 443
 444 const struct filtab {
 445   const char *name;
 446   void (*func)(filter */*f*/, unsigned /*ac*/, char **/*av*/);
 447 } filtab[] = {
 448   { "send",     addsend },
 449   { "fork",     addfork },
 450   { "delay",    adddelay },
 451   { "drop",     adddrop },
 452   { "corrupt",  addcorrupt },
 453   { 0,          0 }
 454 };
 455
 456 static void dofilter(peer *from, peer *to, unsigned ac, char **av)
 457 {
 458   filter **ff, *f = CREATE(filter);
 459   const struct filtab *ft;
 460   if (ac < 1)
 461     die(1, "syntax: {l,r,}filt:NAME:...");
 462   f->next = 0;
 463   f->p_from = from;
 464   f->p_to = to;
 465   f->state = 0;
 466   for (ff = &from->f; *ff; ff = &(*ff)->next)
 467     ;
 468   *ff = f;
 469   for (ft = filtab; ft->name; ft++) {
 470     if (strcmp(av[0], ft->name) == 0) {
 471       ft->func(f, ac - 1, av + 1);
 472       return;
 473     }
 474   }
 475   die(1, "unknown filter `%s'", av[0]);
 476 }
 477
 478 /*----- Flooding ----------------------------------------------------------*/
 479
 480 typedef struct flood {
 481   peer *p;
 482   unsigned type;
 483   size_t sz;
 484   unsigned long t;
 485   sel_timer tm;
 486 } flood;
 487
 488 static void setflood(flood *f);
 489
 490 static void floodtimer(struct timeval *tv, void *vv)
 491 {
 492   flood *f = vv;
 493   octet buf[PKBUFSZ];
 494   size_t sz;
 495
 496   sz = RND(f->sz);
 497   sz += RND(f->sz);
 498   sz += RND(f->sz);
 499   sz += RND(f->sz);
 500   sz /= 2;
 501
 502   rng->ops->fill(rng, buf, sz);
 503   if (f->type < 0x100)
 504     buf[0] = f->type;
 505   puts("flood packet");
 506   PASS(f->p->f, buf, sz);
 507   setflood(f);
 508 }
 509
 510 static void setflood(flood *f)
 511 {
 512   struct timeval tv;
 513   gettimeofday(&tv, 0);
 514   TV_ADDL(&tv, &tv, 0, RND(f->t));
 515   sel_addtimer(&sel, &f->tm, &tv, floodtimer, f);
 516 }
 517
 518 static void doflood(peer *p, unsigned ac, char **av)
 519 {
 520   flood *f;
 521   if (ac > 3)
 522     die(1, "syntax: flood[:TYPE:MILLIS:SIZE]");
 523   f = CREATE(flood);
 524   f->p = p;
 525   if (ac > 0)
 526     f->type = strtoul(av[0], 0, 16);
 527   else
 528     f->type = 0x100;
 529   if (ac > 1)
 530     f->t = atoi(av[1]);
 531   else
 532     f->t = 10;
 533   if (ac > 2)
 534     f->sz = atoi(av[2]);
 535   else
 536     f->sz = 128;
 537   f->t *= 1000;
 538   setflood(f);
 539 }
 540
 541 /*----- Configuration commands --------------------------------------------*/
 542
 543 static void parse(char *p);
 544
 545 static void addflood(unsigned ac, char **av) {
 546   doflood(&peers[0], ac, av);
 547   doflood(&peers[1], ac, av);
 548 }
 549 static void addlflood(unsigned ac, char **av) {
 550   doflood(&peers[0], ac, av);
 551 }
 552 static void addrflood(unsigned ac, char **av) {
 553   doflood(&peers[1], ac, av);
 554 }
 555
 556 static void addfilter(unsigned ac, char **av) {
 557   dofilter(&peers[0], &peers[1], ac, av);
 558   dofilter(&peers[1], &peers[0], ac, av);
 559 }
 560 static void addlfilter(unsigned ac, char **av) {
 561   dofilter(&peers[0], &peers[1], ac, av);
 562 }
 563 static void addrfilter(unsigned ac, char **av) {
 564   dofilter(&peers[1], &peers[0], ac, av);
 565 }
 566
 567 static void include(unsigned ac, char **av)
 568 {
 569   FILE *fp;
 570   dstr d = DSTR_INIT;
 571   if (!ac)
 572     die(1, "syntax: include:FILE:...");
 573   while (*av) {
 574     if ((fp = fopen(*av, "r")) == 0)
 575       die(1, "fopen `%s': %s", *av, strerror(errno));
 576     while (dstr_putline(&d, fp) != EOF) {
 577       parse(d.buf);
 578       DRESET(&d);
 579     }
 580     fclose(fp);
 581     av++;
 582   }
 583 }
 584
 585 const struct cmdtab {
 586   const char *name;
 587   void (*func)(unsigned /*ac*/, char **/*av*/);
 588 } cmdtab[] = {
 589   { "peer",     addpeer },
 590   { "include",  include },
 591   { "filt",     addfilter },
 592   { "lfilt",    addlfilter },
 593   { "rfilt",    addrfilter },
 594   { "next",     nextfork },
 595   { "flood",    addflood },
 596   { "lflood",   addlflood },
 597   { "rflood",   addrflood },
 598   { 0,          0 }
 599 };
 600
 601 #define AVMAX 16
 602
 603 static void parse(char *p)
 604 {
 605   char *v[AVMAX];
 606   unsigned c = 0;
 607   const struct cmdtab *ct;
 608
 609   p = strtok(p, ":");
 610   if (!p || *p == '#')
 611     return;
 612   do {
 613     v[c++] = p;
 614     p = strtok(0, ":");
 615   } while (p && c < AVMAX - 1);
 616   v[c] = 0;
 617   for (ct = cmdtab; ct->name; ct++) {
 618     if (strcmp(ct->name, v[0]) == 0) {
 619       ct->func(c - 1, v + 1);
 620       return;
 621     }
 622   }
 623   die(1, "unknown command `%s'", v[0]);
 624 }
 625
 626 /*----- Main driver -------------------------------------------------------*/
 627
 628 static void version(FILE *fp)
 629   { pquis(fp, "$, TrIPE version " VERSION "\n"); }
 630
 631 static void usage(FILE *fp)
 632   { pquis(fp, "Usage: $ [-k KEYRING] DIRECTIVE...\n"); }
 633
 634 static void help(FILE *fp)
 635 {
 636   version(fp);
 637   putc('\n', fp);
 638   usage(fp);
 639   fputs("\n\
 640 Options:\n\
 641 \n\
 642 -h, --help              Show this help text.\n\
 643 -v, --version           Show the version number.\n\
 644 -u, --usage             Show terse usage summary.\n\
 645 \n\
 646 -k, --keyring=FILE      Fetch keys from FILE.\n\
 647 \n\
 648 Directives:\n\
 649   peer:NAME:LOCAL-PORT:REMOTE-ADDR:REMOTE-PORT\n\
 650   include:FILE\n\
 651   {,l,r}filt:FILTER:ARGS:...\n\
 652   next:TAG\n\
 653   {,l,r}flood:TYPE:MILLIS:SIZE\n\
 654 \n\
 655 Filters:\n\
 656   send\n\
 657   fork:TAG\n\
 658   delay:QLEN[:MILLIS:P-REPLAY]\n\
 659   drop[:P-DROP]\n\
 660   corrupt[:P-CORRUPT]\n",
 661         fp);
 662 }
 663
 664 int main(int argc, char *argv[])
 665 {
 666   const char *kfname = "keyring.pub";
 667   int i;
 668   unsigned f = 0;
 669   char buf[16];
 670
 671 #define f_bogus 1u
 672
 673   ego(argv[0]);
 674   for (;;) {
 675     static const struct option opt[] = {
 676       { "help",         0,              0,      'h' },
 677       { "version",      0,              0,      'v' },
 678       { "usage",        0,              0,      'u' },
 679       { "keyring",      OPTF_ARGREQ,    0,      'k' },
 680       { 0,              0,              0,      0 }
 681     };
 682     if ((i = mdwopt(argc, argv, "hvuk:", opt, 0, 0, 0)) < 0)
 683       break;
 684     switch (i) {
 685       case 'h':
 686         help(stdout);
 687         exit(0);
 688       case 'v':
 689         version(stdout);
 690         exit(0);
 691       case 'u':
 692         usage(stdout);
 693         exit(0);
 694       case 'k':
 695         kfname = optarg;
 696         break;
 697       default:
 698         f |= f_bogus;
 699         break;
 700     }
 701   }
 702   if (f & f_bogus) {
 703     usage(stderr);
 704     exit(1);
 705   }
 706   rand_noisesrc(RAND_GLOBAL, &noise_source);
 707   rand_seed(RAND_GLOBAL, 160);
 708   rand_get(RAND_GLOBAL, buf, sizeof(buf));
 709   rng = rc4_rand(buf, sizeof(buf));
 710   sel_init(&sel);
 711   if (key_open(&keys, kfname, KOPEN_READ, key_moan, 0))
 712     die(1, "couldn't open `%s': %s", kfname, strerror(errno));
 713   for (i = optind; i < argc; i++)
 714     parse(argv[i]);
 715   if (npeer != 2)
 716     die(1, "need two peers");
 717   for (;;) {
 718     if (sel_select(&sel) && errno != EINTR)
 719       die(1, "select failed: %s", strerror(errno));
 720   }
 721
 722 #undef f_bogus
 723 }
 724
 725 /*----- That's all, folks -------------------------------------------------*/