policies.c 112 KB
Newer Older
1
/* Copyright (c) 2001-2004, Roger Dingledine.
2
 * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
Nick Mathewson's avatar
Nick Mathewson committed
3
 * Copyright (c) 2007-2019, The Tor Project, Inc. */
4
5
6
7
8
/* See LICENSE for licensing information */

/**
 * \file policies.c
 * \brief Code to parse and use address policies and exit policies.
9
10
11
12
13
14
15
 *
 * We have two key kinds of address policy: full and compressed.  A full
 * policy is an array of accept/reject patterns, to be applied in order.
 * A short policy is simply a list of ports.  This module handles both
 * kinds, including generic functions to apply them to addresses, and
 * also including code to manage the global policies that we apply to
 * incoming and outgoing connections.
16
17
 **/

Nick Mathewson's avatar
Nick Mathewson committed
18
19
#define POLICIES_PRIVATE

20
21
22
#include "core/or/or.h"
#include "feature/client/bridges.h"
#include "app/config/config.h"
23
#include "core/or/policies.h"
24
#include "feature/dirparse/policy_parse.h"
25
26
27
28
#include "feature/nodelist/microdesc.h"
#include "feature/nodelist/networkstatus.h"
#include "feature/nodelist/nodelist.h"
#include "feature/relay/router.h"
29
#include "feature/relay/routermode.h"
30
#include "lib/geoip/geoip.h"
31
#include "ht.h"
32
#include "lib/crypt_ops/crypto_rand.h"
33
#include "lib/encoding/confline.h"
34
#include "trunnel/ed25519_cert.h"
35

36
37
38
39
40
41
42
#include "core/or/addr_policy_st.h"
#include "feature/dirclient/dir_server_st.h"
#include "feature/nodelist/microdesc_st.h"
#include "feature/nodelist/node_st.h"
#include "core/or/port_cfg_st.h"
#include "feature/nodelist/routerinfo_st.h"
#include "feature/nodelist/routerstatus_st.h"
43

44
45
46
/** Maximum length of an exit policy summary. */
#define MAX_EXITPOLICY_SUMMARY_LEN 1000

47
/** Policy that addresses for incoming SOCKS connections must match. */
48
static smartlist_t *socks_policy = NULL;
49
/** Policy that addresses for incoming directory connections must match. */
50
static smartlist_t *dir_policy = NULL;
51
52
/** Policy that addresses for incoming router descriptors must match in order
 * to be published by us. */
53
static smartlist_t *authdir_reject_policy = NULL;
54
55
/** Policy that addresses for incoming router descriptors must match in order
 * to be marked as valid in our networkstatus. */
56
static smartlist_t *authdir_invalid_policy = NULL;
57
58
/** Policy that addresses for incoming router descriptors must <b>not</b>
 * match in order to not be marked as BadExit. */
59
static smartlist_t *authdir_badexit_policy = NULL;
60
61
62

/** Parsed addr_policy_t describing which addresses we believe we can start
 * circuits at. */
63
static smartlist_t *reachable_or_addr_policy = NULL;
64
65
/** Parsed addr_policy_t describing which addresses we believe we can connect
 * to directories at. */
66
67
static smartlist_t *reachable_dir_addr_policy = NULL;

68
69
70
71
72
/** Element of an exit policy summary */
typedef struct policy_summary_item_t {
    uint16_t prt_min; /**< Lowest port number to accept/reject. */
    uint16_t prt_max; /**< Highest port number to accept/reject. */
    uint64_t reject_count; /**< Number of IP-Addresses that are rejected to
Nick Mathewson's avatar
Nick Mathewson committed
73
                                this port range. */
74
    unsigned int accepted:1; /** Has this port already been accepted */
75
76
} policy_summary_item_t;

77
78
79
80
81
82
83
84
85
/** Private networks.  This list is used in two places, once to expand the
 *  "private" keyword when parsing our own exit policy, secondly to ignore
 *  just such networks when building exit policy summaries.  It is important
 *  that all authorities agree on that list when creating summaries, so don't
 *  just change this without a proper migration plan and a proposal and stuff.
 */
static const char *private_nets[] = {
  "0.0.0.0/8", "169.254.0.0/16",
  "127.0.0.0/8", "192.168.0.0/16", "10.0.0.0/8", "172.16.0.0/12",
86
87
88
89
  "[::]/8",
  "[fc00::]/7", "[fe80::]/10", "[fec0::]/10", "[ff00::]/8", "[::]/127",
  NULL
};
90

91
static int policies_parse_exit_policy_internal(
92
93
94
95
96
97
98
                                      config_line_t *cfg,
                                      smartlist_t **dest,
                                      int ipv6_exit,
                                      int rejectprivate,
                                      const smartlist_t *configured_addresses,
                                      int reject_interface_addresses,
                                      int reject_configured_port_addresses,
99
100
                                      int add_default_policy,
                                      int add_reduced_policy);
101

102
103
104
105
106
107
108
109
110
111
/** Replace all "private" entries in *<b>policy</b> with their expanded
 * equivalents. */
void
policy_expand_private(smartlist_t **policy)
{
  uint16_t port_min, port_max;

  int i;
  smartlist_t *tmp;

112
  if (!*policy) /*XXXX disallow NULL policies? */
113
114
    return;

115
  tmp = smartlist_new();
116

117
  SMARTLIST_FOREACH_BEGIN(*policy, addr_policy_t *, p) {
118
119
120
121
122
     if (! p->is_private) {
       smartlist_add(tmp, p);
       continue;
     }
     for (i = 0; private_nets[i]; ++i) {
123
124
125
126
       addr_policy_t newpolicy;
       memcpy(&newpolicy, p, sizeof(addr_policy_t));
       newpolicy.is_private = 0;
       newpolicy.is_canonical = 0;
127
128
       if (tor_addr_parse_mask_ports(private_nets[i], 0,
                               &newpolicy.addr,
129
                               &newpolicy.maskbits, &port_min, &port_max)<0) {
130
         tor_assert_unreached();
131
       }
132
       smartlist_add(tmp, addr_policy_get_canonical_entry(&newpolicy));
133
134
     }
     addr_policy_free(p);
135
  } SMARTLIST_FOREACH_END(p);
136
137
138
139

  smartlist_free(*policy);
  *policy = tmp;
}
140

141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
/** Expand each of the AF_UNSPEC elements in *<b>policy</b> (which indicate
 * protocol-neutral wildcards) into a pair of wildcard elements: one IPv4-
 * specific and one IPv6-specific. */
void
policy_expand_unspec(smartlist_t **policy)
{
  smartlist_t *tmp;
  if (!*policy)
    return;

  tmp = smartlist_new();
  SMARTLIST_FOREACH_BEGIN(*policy, addr_policy_t *, p) {
    sa_family_t family = tor_addr_family(&p->addr);
    if (family == AF_INET6 || family == AF_INET || p->is_private) {
      smartlist_add(tmp, p);
    } else if (family == AF_UNSPEC) {
      addr_policy_t newpolicy_ipv4;
      addr_policy_t newpolicy_ipv6;
      memcpy(&newpolicy_ipv4, p, sizeof(addr_policy_t));
      memcpy(&newpolicy_ipv6, p, sizeof(addr_policy_t));
      newpolicy_ipv4.is_canonical = 0;
      newpolicy_ipv6.is_canonical = 0;
      if (p->maskbits != 0) {
        log_warn(LD_BUG, "AF_UNSPEC policy with maskbits==%d", p->maskbits);
        newpolicy_ipv4.maskbits = 0;
        newpolicy_ipv6.maskbits = 0;
      }
      tor_addr_from_ipv4h(&newpolicy_ipv4.addr, 0);
      tor_addr_from_ipv6_bytes(&newpolicy_ipv6.addr,
                               "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0");
      smartlist_add(tmp, addr_policy_get_canonical_entry(&newpolicy_ipv4));
      smartlist_add(tmp, addr_policy_get_canonical_entry(&newpolicy_ipv6));
      addr_policy_free(p);
    } else {
      log_warn(LD_BUG, "Funny-looking address policy with family %d", family);
      smartlist_add(tmp, p);
    }
  } SMARTLIST_FOREACH_END(p);

  smartlist_free(*policy);
  *policy = tmp;
}

184
/**
185
 * Given a linked list of config lines containing "accept[6]" and "reject[6]"
186
 * tokens, parse them and append the result to <b>dest</b>. Return -1
187
 * if any tokens are malformed (and don't append any), else return 0.
188
189
190
191
 *
 * If <b>assume_action</b> is nonnegative, then insert its action
 * (ADDR_POLICY_ACCEPT or ADDR_POLICY_REJECT) for items that specify no
 * action.
192
193
 */
static int
194
parse_addr_policy(config_line_t *cfg, smartlist_t **dest,
195
196
                  int assume_action)
{
197
  smartlist_t *result;
198
  smartlist_t *entries;
199
  addr_policy_t *item;
200
  int malformed_list;
201
202
203
204
205
  int r = 0;

  if (!cfg)
    return 0;

206
207
  result = smartlist_new();
  entries = smartlist_new();
208
209
210
  for (; cfg; cfg = cfg->next) {
    smartlist_split_string(entries, cfg->value, ",",
                           SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
211
    SMARTLIST_FOREACH_BEGIN(entries, const char *, ent) {
212
      log_debug(LD_CONFIG,"Adding new entry '%s'",ent);
213
214
215
      malformed_list = 0;
      item = router_parse_addr_policy_item_from_string(ent, assume_action,
                                                       &malformed_list);
216
217
      if (item) {
        smartlist_add(result, item);
218
219
220
221
      } else if (malformed_list) {
        /* the error is so severe the entire list should be discarded */
        log_warn(LD_CONFIG, "Malformed policy '%s'. Discarding entire policy "
                 "list.", ent);
222
        r = -1;
223
224
225
226
227
228
      } else {
        /* the error is minor: don't add the item, but keep processing the
         * rest of the policies in the list */
        log_debug(LD_CONFIG, "Ignored policy '%s' due to non-fatal error. "
                  "The remainder of the policy list will be used.",
                  ent);
229
      }
230
    } SMARTLIST_FOREACH_END(ent);
231
232
233
234
    SMARTLIST_FOREACH(entries, char *, ent, tor_free(ent));
    smartlist_clear(entries);
  }
  smartlist_free(entries);
235
236
237
238
  if (r == -1) {
    addr_policy_list_free(result);
  } else {
    policy_expand_private(&result);
239
    policy_expand_unspec(&result);
240
241
242
243
244
245
246
247
248

    if (*dest) {
      smartlist_add_all(*dest, result);
      smartlist_free(result);
    } else {
      *dest = result;
    }
  }

249
250
251
252
  return r;
}

/** Helper: parse the Reachable(Dir|OR)?Addresses fields into
253
254
255
256
 * reachable_(or|dir)_addr_policy.  The options should already have
 * been validated by validate_addr_policies.
 */
static int
257
258
parse_reachable_addresses(void)
{
259
  const or_options_t *options = get_options();
260
  int ret = 0;
261
262
263
264
265
266
267
268

  if (options->ReachableDirAddresses &&
      options->ReachableORAddresses &&
      options->ReachableAddresses) {
    log_warn(LD_CONFIG,
             "Both ReachableDirAddresses and ReachableORAddresses are set. "
             "ReachableAddresses setting will be ignored.");
  }
269
  addr_policy_list_free(reachable_or_addr_policy);
270
271
272
273
274
275
276
277
278
279
280
  reachable_or_addr_policy = NULL;
  if (!options->ReachableORAddresses && options->ReachableAddresses)
    log_info(LD_CONFIG,
             "Using ReachableAddresses as ReachableORAddresses.");
  if (parse_addr_policy(options->ReachableORAddresses ?
                          options->ReachableORAddresses :
                          options->ReachableAddresses,
                        &reachable_or_addr_policy, ADDR_POLICY_ACCEPT)) {
    log_warn(LD_CONFIG,
             "Error parsing Reachable%sAddresses entry; ignoring.",
             options->ReachableORAddresses ? "OR" : "");
281
    ret = -1;
282
283
  }

284
  addr_policy_list_free(reachable_dir_addr_policy);
285
286
287
288
289
290
291
292
293
294
295
  reachable_dir_addr_policy = NULL;
  if (!options->ReachableDirAddresses && options->ReachableAddresses)
    log_info(LD_CONFIG,
             "Using ReachableAddresses as ReachableDirAddresses");
  if (parse_addr_policy(options->ReachableDirAddresses ?
                          options->ReachableDirAddresses :
                          options->ReachableAddresses,
                        &reachable_dir_addr_policy, ADDR_POLICY_ACCEPT)) {
    if (options->ReachableDirAddresses)
      log_warn(LD_CONFIG,
               "Error parsing ReachableDirAddresses entry; ignoring.");
296
    ret = -1;
297
298
  }

299
300
  /* We ignore ReachableAddresses for relays */
  if (!server_mode(options)) {
Nick Mathewson's avatar
Nick Mathewson committed
301
302
    if (policy_is_reject_star(reachable_or_addr_policy, AF_UNSPEC, 0)
        || policy_is_reject_star(reachable_dir_addr_policy, AF_UNSPEC,0)) {
303
304
305
306
      log_warn(LD_CONFIG, "Tor cannot connect to the Internet if "
               "ReachableAddresses, ReachableORAddresses, or "
               "ReachableDirAddresses reject all addresses. Please accept "
               "some addresses in these options.");
307
    } else if (options->ClientUseIPv4 == 1
Nick Mathewson's avatar
Nick Mathewson committed
308
309
       && (policy_is_reject_star(reachable_or_addr_policy, AF_INET, 0)
           || policy_is_reject_star(reachable_dir_addr_policy, AF_INET, 0))) {
310
311
312
313
314
          log_warn(LD_CONFIG, "You have set ClientUseIPv4 1, but "
                   "ReachableAddresses, ReachableORAddresses, or "
                   "ReachableDirAddresses reject all IPv4 addresses. "
                   "Tor will not connect using IPv4.");
    } else if (fascist_firewall_use_ipv6(options)
Nick Mathewson's avatar
Nick Mathewson committed
315
316
       && (policy_is_reject_star(reachable_or_addr_policy, AF_INET6, 0)
         || policy_is_reject_star(reachable_dir_addr_policy, AF_INET6, 0))) {
317
318
          log_warn(LD_CONFIG, "You have configured tor to use or prefer IPv6 "
                   "(or UseBridges 1), but "
319
320
321
                   "ReachableAddresses, ReachableORAddresses, or "
                   "ReachableDirAddresses reject all IPv6 addresses. "
                   "Tor will not connect using IPv6.");
322
323
324
    }
  }

Roger Dingledine's avatar
Roger Dingledine committed
325
  /* Append a reject *:* to reachable_(or|dir)_addr_policy */
326
327
328
329
330
331
332
  if (!ret && (options->ReachableDirAddresses ||
               options->ReachableORAddresses ||
               options->ReachableAddresses)) {
    append_exit_policy_string(&reachable_or_addr_policy, "reject *:*");
    append_exit_policy_string(&reachable_dir_addr_policy, "reject *:*");
  }

333
  return ret;
334
335
}

336
337
338
339
/* Return true iff ClientUseIPv4 0 or ClientUseIPv6 0 might block any OR or Dir
 * address:port combination. */
static int
firewall_is_fascist_impl(void)
340
341
342
343
{
  const or_options_t *options = get_options();
  /* Assume every non-bridge relay has an IPv4 address.
   * Clients which use bridges may only know the IPv6 address of their
344
345
   * bridge, but they will connect regardless of the ClientUseIPv6 setting. */
  return options->ClientUseIPv4 == 0;
346
347
348
349
}

/** Return true iff the firewall options, including ClientUseIPv4 0 and
 * ClientUseIPv6 0, might block any OR address:port combination.
350
351
 * Address preferences may still change which address is selected even if
 * this function returns false.
352
353
354
355
 */
int
firewall_is_fascist_or(void)
{
356
357
358
359
360
  return (reachable_or_addr_policy != NULL || firewall_is_fascist_impl());
}

/** Return true iff the firewall options, including ClientUseIPv4 0 and
 * ClientUseIPv6 0, might block any Dir address:port combination.
361
362
 * Address preferences may still change which address is selected even if
 * this function returns false.
363
364
365
366
367
 */
int
firewall_is_fascist_dir(void)
{
  return (reachable_dir_addr_policy != NULL || firewall_is_fascist_impl());
368
369
370
371
372
373
}

/** Return true iff <b>policy</b> (possibly NULL) will allow a
 * connection to <b>addr</b>:<b>port</b>.
 */
static int
374
addr_policy_permits_tor_addr(const tor_addr_t *addr, uint16_t port,
375
                            smartlist_t *policy)
376
377
{
  addr_policy_result_t p;
378
  p = compare_tor_addr_to_addr_policy(addr, port, policy);
379
380
381
382
383
384
385
386
387
388
389
390
391
  switch (p) {
    case ADDR_POLICY_PROBABLY_ACCEPTED:
    case ADDR_POLICY_ACCEPTED:
      return 1;
    case ADDR_POLICY_PROBABLY_REJECTED:
    case ADDR_POLICY_REJECTED:
      return 0;
    default:
      log_warn(LD_BUG, "Unexpected result: %d", (int)p);
      return 0;
  }
}

392
393
394
395
/** Return true iff <b> policy</b> (possibly NULL) will allow a connection to
 * <b>addr</b>:<b>port</b>.  <b>addr</b> is an IPv4 address given in host
 * order. */
/* XXXX deprecate when possible. */
396
397
398
399
400
401
402
403
404
static int
addr_policy_permits_address(uint32_t addr, uint16_t port,
                            smartlist_t *policy)
{
  tor_addr_t a;
  tor_addr_from_ipv4h(&a, addr);
  return addr_policy_permits_tor_addr(&a, port, policy);
}

405
406
407
/** Return true iff we think our firewall will let us make a connection to
 * addr:port.
 *
408
409
 * If we are configured as a server, ignore any address family preference and
 * just use IPv4.
410
411
412
413
414
 * Otherwise:
 *  - return false for all IPv4 addresses:
 *    - if ClientUseIPv4 is 0, or
 *      if pref_only and pref_ipv6 are both true;
 *  - return false for all IPv6 addresses:
415
 *    - if fascist_firewall_use_ipv6() is 0, or
416
417
418
419
420
421
422
423
 *    - if pref_only is true and pref_ipv6 is false.
 *
 * Return false if addr is NULL or tor_addr_is_null(), or if port is 0. */
STATIC int
fascist_firewall_allows_address(const tor_addr_t *addr,
                                uint16_t port,
                                smartlist_t *firewall_policy,
                                int pref_only, int pref_ipv6)
424
{
425
  const or_options_t *options = get_options();
426
  const int client_mode = !server_mode(options);
427
428
429
430
431

  if (!addr || tor_addr_is_null(addr) || !port) {
    return 0;
  }

432
433
434
435
436
437
  /* Clients stop using IPv4 if it's disabled. In most cases, clients also
   * stop using IPv4 if it's not preferred.
   * Servers must have IPv4 enabled and preferred. */
  if (tor_addr_family(addr) == AF_INET && client_mode &&
      (!options->ClientUseIPv4 || (pref_only && pref_ipv6))) {
    return 0;
438
439
  }

440
441
  /* Clients and Servers won't use IPv6 unless it's enabled (and in most
   * cases, IPv6 must also be preferred before it will be used). */
442
  if (tor_addr_family(addr) == AF_INET6 &&
443
      (!fascist_firewall_use_ipv6(options) || (pref_only && !pref_ipv6))) {
444
    return 0;
445
  }
446

447
  return addr_policy_permits_tor_addr(addr, port,
448
449
450
                                      firewall_policy);
}

451
/** Is this client configured to use IPv6?
452
453
454
 * Returns true if the client might use IPv6 for some of its connections
 * (including dual-stack and IPv6-only clients), and false if it will never
 * use IPv6 for any connections.
455
456
 * Use node_ipv6_or/dir_preferred() when checking a specific node and OR/Dir
 * port: it supports bridge client per-node IPv6 preferences.
457
 */
Nick Mathewson's avatar
Nick Mathewson committed
458
459
int
fascist_firewall_use_ipv6(const or_options_t *options)
460
{
461
  /* Clients use IPv6 if it's set, or they use bridges, or they don't use
462
463
464
465
   * IPv4, or they prefer it.
   * ClientPreferIPv6DirPort is deprecated, but check it anyway. */
  return (options->ClientUseIPv6 == 1 || options->ClientUseIPv4 == 0 ||
          options->ClientPreferIPv6ORPort == 1 ||
466
467
          options->ClientPreferIPv6DirPort == 1 || options->UseBridges == 1 ||
          options->ClientAutoIPv6ORPort == 1);
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
}

/** Do we prefer to connect to IPv6, ignoring ClientPreferIPv6ORPort and
 * ClientPreferIPv6DirPort?
 * If we're unsure, return -1, otherwise, return 1 for IPv6 and 0 for IPv4.
 */
static int
fascist_firewall_prefer_ipv6_impl(const or_options_t *options)
{
  /*
   Cheap implementation of config options ClientUseIPv4 & ClientUseIPv6 --
   If we're a server or IPv6 is disabled, use IPv4.
   If IPv4 is disabled, use IPv6.
   */

  if (server_mode(options) || !fascist_firewall_use_ipv6(options)) {
    return 0;
  }

  if (!options->ClientUseIPv4) {
    return 1;
  }

  return -1;
}

494
495
/* Choose whether we prefer IPv4 or IPv6 by randomly choosing an address
 * family. Return 0 for IPv4, and 1 for IPv6. */
496
497
MOCK_IMPL(int,
fascist_firewall_rand_prefer_ipv6_addr, (void))
498
499
500
501
502
{
  /* TODO: Check for failures, and infer our preference based on this. */
  return crypto_rand_int(2);
}

503
/** Do we prefer to connect to IPv6 ORPorts?
504
505
 * Use node_ipv6_or_preferred() whenever possible: it supports bridge client
 * per-node IPv6 preferences.
506
507
508
509
510
511
512
513
514
515
516
 */
int
fascist_firewall_prefer_ipv6_orport(const or_options_t *options)
{
  int pref_ipv6 = fascist_firewall_prefer_ipv6_impl(options);

  if (pref_ipv6 >= 0) {
    return pref_ipv6;
  }

  /* We can use both IPv4 and IPv6 - which do we prefer? */
517
518
519
520
  if (options->ClientAutoIPv6ORPort == 1) {
    /* If ClientAutoIPv6ORPort is 1, we prefer IPv4 or IPv6 at random. */
    return fascist_firewall_rand_prefer_ipv6_addr();
  } else if (options->ClientPreferIPv6ORPort == 1) {
521
522
523
524
    return 1;
  }

  return 0;
525
526
}

527
/** Do we prefer to connect to IPv6 DirPorts?
528
529
530
 *
 * (node_ipv6_dir_preferred() doesn't support bridge client per-node IPv6
 * preferences. There's no reason to use it instead of this function.)
531
 */
532
int
533
fascist_firewall_prefer_ipv6_dirport(const or_options_t *options)
534
{
535
536
537
538
539
540
541
542
543
544
545
546
  int pref_ipv6 = fascist_firewall_prefer_ipv6_impl(options);

  if (pref_ipv6 >= 0) {
    return pref_ipv6;
  }

  /* We can use both IPv4 and IPv6 - which do we prefer? */
  if (options->ClientPreferIPv6DirPort == 1) {
    return 1;
  }

  return 0;
547
548
}

549
550
551
/** Return true iff we think our firewall will let us make a connection to
 * addr:port. Uses ReachableORAddresses or ReachableDirAddresses based on
 * fw_connection.
552
553
554
 * If pref_only is true, return true if addr is in the client's preferred
 * address family, which is IPv6 if pref_ipv6 is true, and IPv4 otherwise.
 * If pref_only is false, ignore pref_ipv6, and return true if addr is allowed.
555
 */
556
int
557
558
fascist_firewall_allows_address_addr(const tor_addr_t *addr, uint16_t port,
                                     firewall_connection_t fw_connection,
559
                                     int pref_only, int pref_ipv6)
560
561
562
{
  if (fw_connection == FIREWALL_OR_CONNECTION) {
    return fascist_firewall_allows_address(addr, port,
Nick Mathewson's avatar
Nick Mathewson committed
563
                               reachable_or_addr_policy,
564
                               pref_only, pref_ipv6);
565
566
  } else if (fw_connection == FIREWALL_DIR_CONNECTION) {
    return fascist_firewall_allows_address(addr, port,
Nick Mathewson's avatar
Nick Mathewson committed
567
                               reachable_dir_addr_policy,
568
                               pref_only, pref_ipv6);
569
  } else {
570
571
572
573
574
575
576
577
578
    log_warn(LD_BUG, "Bad firewall_connection_t value %d.",
             fw_connection);
    return 0;
  }
}

/** Return true iff we think our firewall will let us make a connection to
 * addr:port (ap). Uses ReachableORAddresses or ReachableDirAddresses based on
 * fw_connection.
579
 * pref_only and pref_ipv6 work as in fascist_firewall_allows_address_addr().
580
 */
581
static int
582
583
fascist_firewall_allows_address_ap(const tor_addr_port_t *ap,
                                   firewall_connection_t fw_connection,
584
                                   int pref_only, int pref_ipv6)
585
586
587
{
  tor_assert(ap);
  return fascist_firewall_allows_address_addr(&ap->addr, ap->port,
588
589
                                              fw_connection, pref_only,
                                              pref_ipv6);
590
591
592
593
594
595
}

/* Return true iff we think our firewall will let us make a connection to
 * ipv4h_or_addr:ipv4_or_port. ipv4h_or_addr is interpreted in host order.
 * Uses ReachableORAddresses or ReachableDirAddresses based on
 * fw_connection.
596
597
 * pref_only and pref_ipv6 work as in fascist_firewall_allows_address_addr().
 */
598
static int
599
600
601
fascist_firewall_allows_address_ipv4h(uint32_t ipv4h_or_addr,
                                          uint16_t ipv4_or_port,
                                          firewall_connection_t fw_connection,
602
                                          int pref_only, int pref_ipv6)
603
604
605
606
{
  tor_addr_t ipv4_or_addr;
  tor_addr_from_ipv4h(&ipv4_or_addr, ipv4h_or_addr);
  return fascist_firewall_allows_address_addr(&ipv4_or_addr, ipv4_or_port,
607
608
                                              fw_connection, pref_only,
                                              pref_ipv6);
609
610
611
612
613
614
}

/** Return true iff we think our firewall will let us make a connection to
 * ipv4h_addr/ipv6_addr. Uses ipv4_orport/ipv6_orport/ReachableORAddresses or
 * ipv4_dirport/ipv6_dirport/ReachableDirAddresses based on IPv4/IPv6 and
 * <b>fw_connection</b>.
615
616
 * pref_only and pref_ipv6 work as in fascist_firewall_allows_address_addr().
 */
617
618
619
620
621
622
static int
fascist_firewall_allows_base(uint32_t ipv4h_addr, uint16_t ipv4_orport,
                             uint16_t ipv4_dirport,
                             const tor_addr_t *ipv6_addr, uint16_t ipv6_orport,
                             uint16_t ipv6_dirport,
                             firewall_connection_t fw_connection,
623
                             int pref_only, int pref_ipv6)
624
625
626
627
628
629
{
  if (fascist_firewall_allows_address_ipv4h(ipv4h_addr,
                                      (fw_connection == FIREWALL_OR_CONNECTION
                                       ? ipv4_orport
                                       : ipv4_dirport),
                                      fw_connection,
630
                                      pref_only, pref_ipv6)) {
631
632
    return 1;
  }
633
634
635
636
637
638

  if (fascist_firewall_allows_address_addr(ipv6_addr,
                                      (fw_connection == FIREWALL_OR_CONNECTION
                                       ? ipv6_orport
                                       : ipv6_dirport),
                                      fw_connection,
639
                                      pref_only, pref_ipv6)) {
640
641
642
643
644
645
    return 1;
  }

  return 0;
}

646
/** Like fascist_firewall_allows_base(), but takes ri. */
647
648
649
static int
fascist_firewall_allows_ri_impl(const routerinfo_t *ri,
                                firewall_connection_t fw_connection,
650
                                int pref_only, int pref_ipv6)
651
652
653
654
655
656
657
658
{
  if (!ri) {
    return 0;
  }

  /* Assume IPv4 and IPv6 DirPorts are the same */
  return fascist_firewall_allows_base(ri->addr, ri->or_port, ri->dir_port,
                                      &ri->ipv6_addr, ri->ipv6_orport,
659
660
                                      ri->dir_port, fw_connection, pref_only,
                                      pref_ipv6);
661
662
}

663
/** Like fascist_firewall_allows_rs, but takes pref_ipv6. */
664
665
666
static int
fascist_firewall_allows_rs_impl(const routerstatus_t *rs,
                                firewall_connection_t fw_connection,
667
                                int pref_only, int pref_ipv6)
668
669
670
671
672
673
674
675
{
  if (!rs) {
    return 0;
  }

  /* Assume IPv4 and IPv6 DirPorts are the same */
  return fascist_firewall_allows_base(rs->addr, rs->or_port, rs->dir_port,
                                      &rs->ipv6_addr, rs->ipv6_orport,
676
677
                                      rs->dir_port, fw_connection, pref_only,
                                      pref_ipv6);
678
679
}

680
/** Like fascist_firewall_allows_base(), but takes rs.
681
682
683
684
685
 * When rs is a fake_status from a dir_server_t, it can have a reachable
 * address, even when the corresponding node does not.
 * nodes can be missing addresses when there's no consensus (IPv4 and IPv6),
 * or when there is a microdescriptor consensus, but no microdescriptors
 * (microdescriptors have IPv6, the microdesc consensus does not). */
686
int
687
688
fascist_firewall_allows_rs(const routerstatus_t *rs,
                           firewall_connection_t fw_connection, int pref_only)
689
{
690
691
692
693
  if (!rs) {
    return 0;
  }

694
695
696
697
698
699
  /* We don't have access to the node-specific IPv6 preference, so use the
   * generic IPv6 preference instead. */
  const or_options_t *options = get_options();
  int pref_ipv6 = (fw_connection == FIREWALL_OR_CONNECTION
                   ? fascist_firewall_prefer_ipv6_orport(options)
                   : fascist_firewall_prefer_ipv6_dirport(options));
700

701
702
  return fascist_firewall_allows_rs_impl(rs, fw_connection, pref_only,
                                         pref_ipv6);
703
704
}

705
706
707
708
709
/** Return true iff we think our firewall will let us make a connection to
 * ipv6_addr:ipv6_orport based on ReachableORAddresses.
 * If <b>fw_connection</b> is FIREWALL_DIR_CONNECTION, returns 0.
 * pref_only and pref_ipv6 work as in fascist_firewall_allows_address_addr().
 */
710
711
712
static int
fascist_firewall_allows_md_impl(const microdesc_t *md,
                                firewall_connection_t fw_connection,
713
                                int pref_only, int pref_ipv6)
714
715
716
717
718
719
720
721
722
723
724
725
{
  if (!md) {
    return 0;
  }

  /* Can't check dirport, it doesn't have one */
  if (fw_connection == FIREWALL_DIR_CONNECTION) {
    return 0;
  }

  /* Also can't check IPv4, doesn't have that either */
  return fascist_firewall_allows_address_addr(&md->ipv6_addr, md->ipv6_orport,
726
727
                                              fw_connection, pref_only,
                                              pref_ipv6);
728
729
}

730
731
/** Like fascist_firewall_allows_base(), but takes node, and looks up pref_ipv6
 * from node_ipv6_or/dir_preferred(). */
732
int
733
734
735
fascist_firewall_allows_node(const node_t *node,
                             firewall_connection_t fw_connection,
                             int pref_only)
736
{
737
738
739
740
741
742
  if (!node) {
    return 0;
  }

  node_assert_ok(node);

743
744
745
746
  const int pref_ipv6 = (fw_connection == FIREWALL_OR_CONNECTION
                         ? node_ipv6_or_preferred(node)
                         : node_ipv6_dir_preferred(node));

747
748
749
  /* Sometimes, the rs is missing the IPv6 address info, and we need to go
   * all the way to the md */
  if (node->ri && fascist_firewall_allows_ri_impl(node->ri, fw_connection,
750
                                                  pref_only, pref_ipv6)) {
751
752
753
    return 1;
  } else if (node->rs && fascist_firewall_allows_rs_impl(node->rs,
                                                         fw_connection,
754
755
                                                         pref_only,
                                                         pref_ipv6)) {
756
757
758
    return 1;
  } else if (node->md && fascist_firewall_allows_md_impl(node->md,
                                                         fw_connection,
759
760
                                                         pref_only,
                                                         pref_ipv6)) {
761
762
763
764
765
766
767
768
    return 1;
  } else {
    /* If we know nothing, assume it's unreachable, we'll never get an address
     * to connect to. */
    return 0;
  }
}

769
/** Like fascist_firewall_allows_rs(), but takes ds. */
770
771
772
773
774
775
776
777
778
779
780
781
int
fascist_firewall_allows_dir_server(const dir_server_t *ds,
                                   firewall_connection_t fw_connection,
                                   int pref_only)
{
  if (!ds) {
    return 0;
  }

  /* A dir_server_t always has a fake_status. As long as it has the same
   * addresses/ports in both fake_status and dir_server_t, this works fine.
   * (See #17867.)
782
   * fascist_firewall_allows_rs only checks the addresses in fake_status. */
783
784
785
786
787
788
789
790
  return fascist_firewall_allows_rs(&ds->fake_status, fw_connection,
                                    pref_only);
}

/** If a and b are both valid and allowed by fw_connection,
 * choose one based on want_a and return it.
 * Otherwise, return whichever is allowed.
 * Otherwise, return NULL.
791
792
 * pref_only and pref_ipv6 work as in fascist_firewall_allows_address_addr().
 */
793
794
795
796
797
static const tor_addr_port_t *
fascist_firewall_choose_address_impl(const tor_addr_port_t *a,
                                     const tor_addr_port_t *b,
                                     int want_a,
                                     firewall_connection_t fw_connection,
798
                                     int pref_only, int pref_ipv6)
799
800
801
802
{
  const tor_addr_port_t *use_a = NULL;
  const tor_addr_port_t *use_b = NULL;

803
804
  if (fascist_firewall_allows_address_ap(a, fw_connection, pref_only,
                                         pref_ipv6)) {
805
806
807
    use_a = a;
  }

808
809
  if (fascist_firewall_allows_address_ap(b, fw_connection, pref_only,
                                         pref_ipv6)) {
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
    use_b = b;
  }

  /* If both are allowed */
  if (use_a && use_b) {
    /* Choose a if we want it */
    return (want_a ? use_a : use_b);
  } else {
    /* Choose a if we have it */
    return (use_a ? use_a : use_b);
  }
}

/** If a and b are both valid and preferred by fw_connection,
 * choose one based on want_a and return it.
 * Otherwise, return whichever is preferred.
 * If neither are preferred, and pref_only is false:
 *  - If a and b are both allowed by fw_connection,
 *    choose one based on want_a and return it.
 *  - Otherwise, return whichever is preferred.
 * Otherwise, return NULL. */
831
STATIC const tor_addr_port_t *
832
833
834
835
fascist_firewall_choose_address(const tor_addr_port_t *a,
                                const tor_addr_port_t *b,
                                int want_a,
                                firewall_connection_t fw_connection,
836
                                int pref_only, int pref_ipv6)
837
838
839
840
{
  const tor_addr_port_t *pref = fascist_firewall_choose_address_impl(
                                                                a, b, want_a,
                                                                fw_connection,
841
                                                                1, pref_ipv6);
842
843
844
845
846
847
848
849
850
  if (pref_only || pref) {
    /* If there is a preferred address, use it. If we can only use preferred
     * addresses, and neither address is preferred, pref will be NULL, and we
     * want to return NULL, so return it. */
    return pref;
  } else {
    /* If there's no preferred address, and we can return addresses that are
     * not preferred, use an address that's allowed */
    return fascist_firewall_choose_address_impl(a, b, want_a, fw_connection,
851
                                                0, pref_ipv6);
852
853
854
855
856
857
858
859
860
861
  }
}

/** Copy an address and port into <b>ap</b> that we think our firewall will
 * let us connect to. Uses ipv4_addr/ipv6_addr and
 * ipv4_orport/ipv6_orport/ReachableORAddresses or
 * ipv4_dirport/ipv6_dirport/ReachableDirAddresses based on IPv4/IPv6 and
 * <b>fw_connection</b>.
 * If pref_only, only choose preferred addresses. In either case, choose
 * a preferred address before an address that's not preferred.
862
 * If both addresses could be chosen (they are both preferred or both allowed)
863
864
 * choose IPv6 if pref_ipv6 is true, otherwise choose IPv4. */
static void
865
866
867
868
869
870
871
872
fascist_firewall_choose_address_base(const tor_addr_t *ipv4_addr,
                                     uint16_t ipv4_orport,
                                     uint16_t ipv4_dirport,
                                     const tor_addr_t *ipv6_addr,
                                     uint16_t ipv6_orport,
                                     uint16_t ipv6_dirport,
                                     firewall_connection_t fw_connection,
                                     int pref_only,
873
                                     int pref_ipv6,
874
875
876
                                     tor_addr_port_t* ap)
{
  const tor_addr_port_t *result = NULL;
877
  const int want_ipv4 = !pref_ipv6;
878
879
880
881

  tor_assert(ipv6_addr);
  tor_assert(ap);

882
883
884
  tor_addr_make_null(&ap->addr, AF_UNSPEC);
  ap->port = 0;

885
886
887
888
889
890
891
892
893
894
895
896
897
  tor_addr_port_t ipv4_ap;
  tor_addr_copy(&ipv4_ap.addr, ipv4_addr);
  ipv4_ap.port = (fw_connection == FIREWALL_OR_CONNECTION
                  ? ipv4_orport
                  : ipv4_dirport);

  tor_addr_port_t ipv6_ap;
  tor_addr_copy(&ipv6_ap.addr, ipv6_addr);
  ipv6_ap.port = (fw_connection == FIREWALL_OR_CONNECTION
                  ? ipv6_orport
                  : ipv6_dirport);

  result = fascist_firewall_choose_address(&ipv4_ap, &ipv6_ap,
898
899
900
                                           want_ipv4,
                                           fw_connection, pref_only,
                                           pref_ipv6);
901
902
903
904
905
906
907

  if (result) {
    tor_addr_copy(&ap->addr, &result->addr);
    ap->port = result->port;
  }
}

908
/** Like fascist_firewall_choose_address_base(), but takes a host-order IPv4
909
 * address as the first parameter. */
910
static void
911
912
913
914
915
916
917
918
fascist_firewall_choose_address_ipv4h(uint32_t ipv4h_addr,
                                      uint16_t ipv4_orport,
                                      uint16_t ipv4_dirport,
                                      const tor_addr_t *ipv6_addr,
                                      uint16_t ipv6_orport,
                                      uint16_t ipv6_dirport,
                                      firewall_connection_t fw_connection,
                                      int pref_only,
919
                                      int pref_ipv6,
920
921
922
923
                                      tor_addr_port_t* ap)
{
  tor_addr_t ipv4_addr;
  tor_addr_from_ipv4h(&ipv4_addr, ipv4h_addr);
924
925
926
927
928
  tor_assert(ap);

  tor_addr_make_null(&ap->addr, AF_UNSPEC);
  ap->port = 0;

929
930
931
932
933
  fascist_firewall_choose_address_base(&ipv4_addr, ipv4_orport,
                                       ipv4_dirport, ipv6_addr,
                                       ipv6_orport, ipv6_dirport,
                                       fw_connection, pref_only,
                                       pref_ipv6, ap);
934
935
}

936
937
938
939
/* Some microdescriptor consensus methods have no IPv6 addresses in rs: they
 * are in the microdescriptors. For these consensus methods, we can't rely on
 * the node's IPv6 address until its microdescriptor is available (when using
 * microdescs).
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
 * But for bridges, rewrite_node_address_for_bridge() updates node->ri with
 * the configured address, so we can trust bridge addresses.
 * (Bridges could gain an IPv6 address if their microdescriptor arrives, but
 * this will never be their preferred address: that is in the config.)
 * Returns true if the node needs a microdescriptor for its IPv6 address, and
 * false if the addresses in the node are already up-to-date.
 */
static int
node_awaiting_ipv6(const or_options_t* options, const node_t *node)
{
  tor_assert(node);

  /* There's no point waiting for an IPv6 address if we'd never use it */
  if (!fascist_firewall_use_ipv6(options)) {
    return 0;
  }

957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
  /* If the node has an IPv6 address, we're not waiting */
  if (node_has_ipv6_addr(node)) {
    return 0;
  }

  /* If the current consensus method and flavour has IPv6 addresses, we're not
   * waiting */
  if (networkstatus_consensus_has_ipv6(options)) {
    return 0;
  }

  /* Bridge clients never use the address from a bridge's md, so there's no
   * need to wait for it. */
  if (node_is_a_configured_bridge(node)) {
    return 0;
  }

974
  /* We are waiting if we_use_microdescriptors_for_circuits() and we have no
975
976
   * md. */
  return (!node->md && we_use_microdescriptors_for_circuits(options));
977
978
}

979
980
981
982
983
/** Like fascist_firewall_choose_address_base(), but takes <b>rs</b>.
 * Consults the corresponding node, then falls back to rs if node is NULL.
 * This should only happen when there's no valid consensus, and rs doesn't
 * correspond to a bridge client's bridge.
 */
984
void
985
986
987
988
989
990
fascist_firewall_choose_address_rs(const routerstatus_t *rs,
                                   firewall_connection_t fw_connection,
                                   int pref_only, tor_addr_port_t* ap)
{
  tor_assert(ap);

991
992
993
  tor_addr_make_null(&ap->addr, AF_UNSPEC);
  ap->port = 0;

994
995
996
997
  if (!rs) {
    return;
  }

998
  const or_options_t *options = get_options();
999
1000
  const node_t *node = node_get_by_id(rs->identity_digest);

For faster browsing, not all history is shown. View entire blame