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/chacha20.h>
  66 #include <catacomb/noise.h>
  67 #include <catacomb/rand.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 static const char *delim = ":";
 101
 102 #define PASS(f, buf, sz) ((f) ? (f)->func((f), (buf), (sz)) : (void)0)
 103 #define RND(i) (rng->ops->range(rng, (i)))
 104
 105 /*----- Peer management ---------------------------------------------------*/
 106
 107 static void dopacket(int fd, unsigned mode, void *vv)
 108 {
 109   octet buf[PKBUFSZ];
 110   peer *p = vv;
 111   int r = read(fd, buf, sizeof(buf));
 112   if (r >= 0) {
 113     printf("recv from `%s'\n", p->name);
 114     PASS(p->f, buf, r);
 115   }
 116 }
 117
 118 static void addpeer(unsigned ac, char **av)
 119 {
 120   struct hostent *h;
 121   struct sockaddr_in sin;
 122   int len = PKBUFSZ;
 123   peer *p;
 124   int fd;
 125
 126   if (ac != 4) die(1, "syntax: peer:NAME:PORT:ADDR:PORT");
 127   if (npeer >= 2) die(1, "enough peers already");
 128   if (!key_bytag(&keys, av[0])) die(1, "no key named `%s'", av[0]);
 129   p = &peers[npeer++];
 130   p->name = xstrdup(av[0]);
 131   if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
 132     die(1, "socket: %s", strerror(errno));
 133   fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 134   memset(&sin, 0, sizeof(sin));
 135   sin.sin_family = AF_INET;
 136   sin.sin_addr.s_addr = INADDR_ANY;
 137   sin.sin_port = htons(atoi(av[1]));
 138   if (bind(fd, (struct sockaddr *)&sin, sizeof(sin)))
 139     die(1, "bind: %s", strerror(errno));
 140   memset(&sin, 0, sizeof(sin));
 141   sin.sin_family = AF_INET;
 142   if ((h = gethostbyname(av[2])) == 0)
 143     die(1, "gethostbyname `%s'", av[2]);
 144   if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &len, sizeof(len)) ||
 145       setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &len, sizeof(len)))
 146     die(1, "setsockopt: %s", strerror(errno));
 147   memcpy(&sin.sin_addr, h->h_addr, sizeof(sin.sin_addr));
 148   sin.sin_port = htons(atoi(av[3]));
 149   if (connect(fd, (struct sockaddr *)&sin, sizeof(sin)))
 150     die(1, "connect: %s", strerror(errno));
 151   sel_initfile(&sel, &p->sf, fd, SEL_READ, dopacket, p);
 152   sel_addfile(&p->sf);
 153 }
 154
 155 /*----- Fork filter -------------------------------------------------------*/
 156
 157 typedef struct forknode {
 158   struct forknode *next;
 159   filter *f;
 160 } forknode;
 161
 162 typedef struct forkfilt {
 163   const char *name;
 164   forknode *fn;
 165 } forkfilt;
 166
 167 static void dofork(filter *f, const octet *buf, size_t sz)
 168 {
 169   forkfilt *ff = f->state;
 170   forknode *fn;
 171   unsigned i = 0;
 172
 173   ff = f->state;
 174   for (fn = ff->fn; fn; fn = fn->next) {
 175     printf("fork branch %u of fork `%s'\n", i++, ff->name);
 176     PASS(fn->f, buf, sz);
 177   }
 178   printf("fork branch %u of fork `%s'\n", i++, ff->name);
 179   PASS(f->next, buf, sz);
 180 }
 181
 182 static void addfork(filter *f, unsigned ac, char **av)
 183 {
 184   forkfilt *ff;
 185   if (ac != 1) die(1, "syntax: filt:fork:NAME");
 186   ff = CREATE(forkfilt);
 187   ff->name = xstrdup(av[0]);
 188   ff->fn = 0;
 189   f->func = dofork;
 190   f->state = ff;
 191 }
 192
 193 static void nextfork(unsigned ac, char **av)
 194 {
 195   unsigned i, j;
 196   filter *f;
 197   forkfilt *ff;
 198   forknode *fn, **ffn;
 199   peer *p;
 200
 201   if (ac < 1) die(1, "syntax: next:NAME:...");
 202   for (i = 0; i < 2; i++) {
 203     p = &peers[i];
 204     for (f = p->f; f; f = f->next) {
 205       if (f->func != dofork) continue;
 206       ff = f->state;
 207       for (j = 0; j < ac; j++)
 208         if (strcmp(av[j], ff->name) == 0) goto match;
 209       continue;
 210     match:
 211       fn = CREATE(forknode);
 212       for (ffn = &ff->fn; *ffn; ffn = &(*ffn)->next);
 213       fn->f = f->next;
 214       f->next = 0;
 215       fn->next = 0;
 216       *ffn = fn;
 217     }
 218   }
 219 }
 220
 221 /*----- Corrupt filter ----------------------------------------------------*/
 222
 223 typedef struct corrupt {
 224   unsigned p_corrupt;
 225 } corrupt;
 226
 227 static void docorrupt(filter *f, const octet *buf, size_t sz)
 228 {
 229   corrupt *c = f->state;
 230   octet b[PKBUFSZ];
 231   memcpy(b, buf, sz);
 232
 233   while (!RND(c->p_corrupt)) {
 234     puts("corrupt packet");
 235     b[RND(sz)] ^= RND(256);
 236   }
 237   PASS(f->next, b, sz);
 238 }
 239
 240 static void addcorrupt(filter *f, unsigned ac, char **av)
 241 {
 242   corrupt *c;
 243   if (ac > 1) die(1, "syntax: filt:corrupt[:P-CORRUPT]");
 244   c = CREATE(corrupt);
 245   if (ac > 0) c->p_corrupt = atoi(av[0]);
 246   else c->p_corrupt = 5;
 247   f->state = c;
 248   f->func = docorrupt;
 249 }
 250
 251 /*----- Drop filter -------------------------------------------------------*/
 252
 253 typedef struct drop {
 254   unsigned p_drop;
 255 } drop;
 256
 257 static void dodrop(filter *f, const octet *buf, size_t sz)
 258 {
 259   drop *d = f->state;
 260
 261   if (!RND(d->p_drop)) puts("drop packet");
 262   else PASS(f->next, buf, sz);
 263 }
 264
 265 static void adddrop(filter *f, unsigned ac, char **av)
 266 {
 267   drop *d;
 268   if (ac > 1) die(1, "syntax: filt:drop[:P-DROP]");
 269   d = CREATE(drop);
 270   if (ac > 0) d->p_drop = atoi(av[0]);
 271   else d->p_drop = 5;
 272   f->state = d;
 273   f->func = dodrop;
 274 }
 275
 276 /*----- Delay filter ------------------------------------------------------*/
 277
 278 typedef struct delaynode {
 279   unsigned flag;
 280   sel_timer tm;
 281   unsigned i;
 282   struct delay *d;
 283   octet *buf;
 284   size_t sz;
 285   unsigned seq;
 286 } delaynode;
 287
 288 typedef struct delay {
 289   unsigned max, n;
 290   unsigned long t;
 291   unsigned p_replay;
 292   filter *f;
 293   delaynode *q;
 294 } delay;
 295
 296 static void dtimer(struct timeval *tv, void *vv);
 297
 298 static void dinsert(delaynode *dn)
 299 {
 300   struct timeval tv;
 301   sel_timer *ta, *tb;
 302   unsigned long tdelta = RND(dn->d->t);
 303   gettimeofday(&tv, 0);
 304   TV_ADDL(&tv, &tv, 0, tdelta);
 305   assert(!dn->flag);
 306   sel_addtimer(&sel, &dn->tm, &tv, dtimer, dn);
 307   dn->flag = 1;
 308   for (ta = tb = sel.timers; ta; ta = ta->next) {
 309     ta = ta->next; if (!ta) break; assert(ta != tb);
 310     ta = ta->next; if (!ta) break; assert(ta != tb);
 311     tb = tb->next;
 312   }
 313   printf(" delay %lu usecs", tdelta);
 314 }
 315
 316 static void dsend(delaynode *dn, unsigned force)
 317 {
 318   delay *d = dn->d;
 319   delaynode *ddn;
 320   unsigned i;
 321
 322   fputs(" send...\n", stdout);
 323   assert(dn->buf);
 324   PASS(d->f->next, dn->buf, dn->sz);
 325   fputs("delay ...", stdout);
 326   if (!force)
 327     dinsert(dn);
 328   else {
 329     xfree(dn->buf);
 330     dn->buf = 0;
 331     d->n--;
 332     if (dn->i < d->n) {
 333       ddn = &d->q[d->n];
 334       sel_rmtimer(&ddn->tm);
 335       sel_addtimer(&sel, &dn->tm, &ddn->tm.tv, dtimer, dn);
 336       dn->flag = 1;
 337       dn->buf = ddn->buf;
 338       dn->sz = ddn->sz;
 339       dn->seq = ddn->seq;
 340       ddn->buf = 0;
 341       ddn->flag = 0;
 342       printf(" move id %u from slot %u to slot %u", ddn->seq, ddn->i, dn->i);
 343     }
 344     for (i = 0; i < d->n; i++) assert(d->q[i].buf);
 345     fputs(" remove", stdout);
 346   }
 347 }
 348
 349 static void dtimer(struct timeval *tv, void *vv)
 350 {
 351   delaynode *dn = vv;
 352   printf("delay timer peer `%s' id %u slot %u",
 353          dn->d->f->p_from->name, dn->seq, dn->i);
 354   dn->flag = 0;
 355   dsend(dn, RND(dn->d->p_replay));
 356   fputc('\n', stdout);
 357 }
 358
 359 static void dodelay(filter *f, const octet *buf, size_t sz)
 360 {
 361   delay *d = f->state;
 362   delaynode *dn;
 363   static unsigned seq = 0;
 364
 365   fputs("delay", stdout);
 366   if (d->n == d->max) {
 367     dn = &d->q[RND(d->n)];
 368     printf(" force uid %u", dn->seq);
 369     sel_rmtimer(&dn->tm);
 370     dn->flag = 0;
 371     dsend(dn, 1);
 372     fputc(';', stdout);
 373   }
 374   dn = &d->q[d->n++];
 375   dn->seq = seq++;
 376   printf(" new id %u in slot %u", dn->seq, dn->i);
 377   dn->buf = xmalloc(sz);
 378   dn->sz = sz;
 379   memcpy(dn->buf, buf, sz);
 380   dinsert(dn);
 381   fputc('\n', stdout);
 382 }
 383
 384 static void adddelay(filter *f, unsigned ac, char **av)
 385 {
 386   delay *d;
 387   unsigned i;
 388
 389   if (ac < 1 || ac > 3) die(1, "syntax: filt:delay:QLEN[:MILLIS:P-REPLAY]");
 390   d = CREATE(delay);
 391   d->max = atoi(av[0]);
 392   if (ac > 1) d->t = strtoul(av[1], 0, 10);
 393   else d->t = 100;
 394   d->t *= 1000;
 395   if (ac > 2) d->p_replay = atoi(av[2]);
 396   else d->p_replay = 20;
 397   d->n = 0;
 398   d->q = xmalloc(d->max * sizeof(delaynode));
 399   d->f = f;
 400   f->state = d;
 401   f->func = dodelay;
 402   for (i = 0; i < d->max; i++) {
 403     d->q[i].d = d;
 404     d->q[i].i = i;
 405     d->q[i].buf = 0;
 406     d->q[i].flag = 0;
 407   }
 408 }
 409
 410 /*----- Filters -----------------------------------------------------------*/
 411
 412 static void dosend(filter *f, const octet *buf, size_t sz)
 413 {
 414   printf("send to `%s'\n", f->p_to->name);
 415   DISCARD(write(f->p_to->sf.fd, buf, sz));
 416 }
 417
 418 static void addsend(filter *f, unsigned ac, char **av)
 419 {
 420   if (ac) die(1, "syntax: filt:send");
 421   f->func = dosend;
 422 }
 423
 424 const struct filtab {
 425   const char *name;
 426   void (*func)(filter */*f*/, unsigned /*ac*/, char **/*av*/);
 427 } filtab[] = {
 428   { "send",     addsend },
 429   { "fork",     addfork },
 430   { "delay",    adddelay },
 431   { "drop",     adddrop },
 432   { "corrupt",  addcorrupt },
 433   { 0,          0 }
 434 };
 435
 436 static void dofilter(peer *from, peer *to, unsigned ac, char **av)
 437 {
 438   filter **ff, *f = CREATE(filter);
 439   const struct filtab *ft;
 440   if (ac < 1) die(1, "syntax: {l,r,}filt:NAME:...");
 441   f->next = 0;
 442   f->p_from = from;
 443   f->p_to = to;
 444   f->state = 0;
 445   for (ff = &from->f; *ff; ff = &(*ff)->next);
 446   *ff = f;
 447   for (ft = filtab; ft->name; ft++)
 448     if (strcmp(av[0], ft->name) == 0)
 449       { ft->func(f, ac - 1, av + 1); return; }
 450   die(1, "unknown filter `%s'", av[0]);
 451 }
 452
 453 /*----- Flooding ----------------------------------------------------------*/
 454
 455 typedef struct flood {
 456   peer *p;
 457   unsigned type;
 458   size_t sz;
 459   unsigned long t;
 460   sel_timer tm;
 461 } flood;
 462
 463 static void setflood(flood *f);
 464
 465 static void floodtimer(struct timeval *tv, void *vv)
 466 {
 467   flood *f = vv;
 468   octet buf[PKBUFSZ];
 469   size_t sz;
 470
 471   sz = RND(f->sz);
 472   sz += RND(f->sz);
 473   sz += RND(f->sz);
 474   sz += RND(f->sz);
 475   sz /= 2;
 476
 477   rng->ops->fill(rng, buf, sz);
 478   if (f->type < 0x100) buf[0] = f->type;
 479   puts("flood packet");
 480   PASS(f->p->f, buf, sz);
 481   setflood(f);
 482 }
 483
 484 static void setflood(flood *f)
 485 {
 486   struct timeval tv;
 487   gettimeofday(&tv, 0);
 488   TV_ADDL(&tv, &tv, 0, RND(f->t));
 489   sel_addtimer(&sel, &f->tm, &tv, floodtimer, f);
 490 }
 491
 492 static void doflood(peer *p, unsigned ac, char **av)
 493 {
 494   flood *f;
 495   if (ac > 3) die(1, "syntax: flood[:TYPE:MILLIS:SIZE]");
 496   f = CREATE(flood);
 497   f->p = p;
 498   if (ac > 0) f->type = strtoul(av[0], 0, 16);
 499   else f->type = 0x100;
 500   if (ac > 1) f->t = atoi(av[1]);
 501   else f->t = 10;
 502   if (ac > 2) f->sz = atoi(av[2]);
 503   else f->sz = 128;
 504   f->t *= 1000;
 505   setflood(f);
 506 }
 507
 508 /*----- Configuration commands --------------------------------------------*/
 509
 510 static void parse(char *p);
 511
 512 static void addflood(unsigned ac, char **av) {
 513   doflood(&peers[0], ac, av);
 514   doflood(&peers[1], ac, av);
 515 }
 516 static void addlflood(unsigned ac, char **av) {
 517   doflood(&peers[0], ac, av);
 518 }
 519 static void addrflood(unsigned ac, char **av) {
 520   doflood(&peers[1], ac, av);
 521 }
 522
 523 static void addfilter(unsigned ac, char **av) {
 524   dofilter(&peers[0], &peers[1], ac, av);
 525   dofilter(&peers[1], &peers[0], ac, av);
 526 }
 527 static void addlfilter(unsigned ac, char **av) {
 528   dofilter(&peers[0], &peers[1], ac, av);
 529 }
 530 static void addrfilter(unsigned ac, char **av) {
 531   dofilter(&peers[1], &peers[0], ac, av);
 532 }
 533
 534 static void include(unsigned ac, char **av)
 535 {
 536   FILE *fp;
 537   dstr d = DSTR_INIT;
 538   if (!ac) die(1, "syntax: include:FILE:...");
 539   while (*av) {
 540     if ((fp = fopen(*av, "r")) == 0)
 541       die(1, "fopen `%s': %s", *av, strerror(errno));
 542     while (dstr_putline(&d, fp) != EOF) { parse(d.buf); DRESET(&d); }
 543     fclose(fp);
 544     av++;
 545   }
 546 }
 547
 548 const struct cmdtab {
 549   const char *name;
 550   void (*func)(unsigned /*ac*/, char **/*av*/);
 551 } cmdtab[] = {
 552   { "peer",     addpeer },
 553   { "include",  include },
 554   { "filt",     addfilter },
 555   { "lfilt",    addlfilter },
 556   { "rfilt",    addrfilter },
 557   { "next",     nextfork },
 558   { "flood",    addflood },
 559   { "lflood",   addlflood },
 560   { "rflood",   addrflood },
 561   { 0,          0 }
 562 };
 563
 564 #define AVMAX 16
 565
 566 static void parse(char *p)
 567 {
 568   char *v[AVMAX];
 569   unsigned c = 0;
 570   const struct cmdtab *ct;
 571
 572   p = strtok(p, delim);
 573   if (!p || *p == '#') return;
 574   do {
 575     v[c++] = p;
 576     p = strtok(0, delim);
 577   } while (p && c < AVMAX - 1);
 578   v[c] = 0;
 579   for (ct = cmdtab; ct->name; ct++) {
 580     if (strcmp(ct->name, v[0]) == 0) {
 581       ct->func(c - 1, v + 1);
 582       return;
 583     }
 584   }
 585   die(1, "unknown command `%s'", v[0]);
 586 }
 587
 588 /*----- Main driver -------------------------------------------------------*/
 589
 590 static void version(FILE *fp)
 591   { pquis(fp, "$, TrIPE version " VERSION "\n"); }
 592
 593 static void usage(FILE *fp)
 594   { pquis(fp, "Usage: $ [-d CHAR] [-k KEYRING] DIRECTIVE...\n"); }
 595
 596 static void help(FILE *fp)
 597 {
 598   version(fp);
 599   putc('\n', fp);
 600   usage(fp);
 601   fputs("\n\
 602 Options:\n\
 603 \n\
 604 -h, --help              Show this help text.\n\
 605 -v, --version           Show the version number.\n\
 606 -u, --usage             Show terse usage summary.\n\
 607 \n\
 608 -d, --delimiter=CHAR    Use CHAR rather than `:' as delimiter.\n\
 609 -k, --keyring=FILE      Fetch keys from FILE.\n\
 610 \n\
 611 Directives:\n\
 612   peer:NAME:LOCAL-PORT:REMOTE-ADDR:REMOTE-PORT\n\
 613   include:FILE\n\
 614   {,l,r}filt:FILTER:ARGS:...\n\
 615   next:TAG\n\
 616   {,l,r}flood:TYPE:MILLIS:SIZE\n\
 617 \n\
 618 Filters:\n\
 619   send\n\
 620   fork:TAG\n\
 621   delay:QLEN[:MILLIS:P-REPLAY]\n\
 622   drop[:P-DROP]\n\
 623   corrupt[:P-CORRUPT]\n",
 624         fp);
 625 }
 626
 627 int main(int argc, char *argv[])
 628 {
 629   const char *kfname = "keyring.pub";
 630   int i;
 631   unsigned f = 0;
 632   char buf[32];
 633   static octet zero[CHACHA_NONCESZ];
 634
 635 #define f_bogus 1u
 636
 637   ego(argv[0]);
 638   for (;;) {
 639     static const struct option opt[] = {
 640       { "help",         0,              0,      'h' },
 641       { "version",      0,              0,      'v' },
 642       { "usage",        0,              0,      'u' },
 643       { "delimiter",    OPTF_ARGREQ,    0,      'd' },
 644       { "keyring",      OPTF_ARGREQ,    0,      'k' },
 645       { 0,              0,              0,      0 }
 646     };
 647     if ((i = mdwopt(argc, argv, "hvud:k:", opt, 0, 0, 0)) < 0) break;
 648     switch (i) {
 649       case 'h': help(stdout); exit(0);
 650       case 'v': version(stdout); exit(0);
 651       case 'u': usage(stdout); exit(0);
 652       case 'd':
 653         if (!optarg[0] || optarg[1])
 654           die(1, "delimiter must be a single character");
 655         delim = optarg;
 656         break;
 657       case 'k': kfname = optarg; break;
 658       default: f |= f_bogus; break;
 659     }
 660   }
 661   if (f & f_bogus) { usage(stderr); exit(1); }
 662
 663   rand_noisesrc(RAND_GLOBAL, &noise_source);
 664   rand_seed(RAND_GLOBAL, 256);
 665   rand_get(RAND_GLOBAL, buf, sizeof(buf));
 666   rng = chacha20_rand(buf, sizeof(buf), zero);
 667   sel_init(&sel);
 668   if (key_open(&keys, kfname, KOPEN_READ, key_moan, 0))
 669     die(1, "couldn't open `%s': %s", kfname, strerror(errno));
 670   for (i = optind; i < argc; i++) parse(argv[i]);
 671   if (npeer != 2) die(1, "need two peers");
 672   for (;;) {
 673     if (sel_select(&sel) && errno != EINTR)
 674       die(1, "select failed: %s", strerror(errno));
 675   }
 676
 677 #undef f_bogus
 678 }
 679
 680 /*----- That's all, folks -------------------------------------------------*/