2 This file is part of GNUnet.
3 (C) 2013 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public Licerevocation as published
7 by the Free Software Foundation; either version 3, or (at your
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public Licerevocation for more details.
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16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
22 * @file revocation/gnunet-service-revocation.c
23 * @brief key revocation service
24 * @author Christian Grothoff
26 * The purpose of this service is to allow users to permanently revoke
27 * (compromised) keys. This is done by flooding the network with the
28 * revocation requests. To reduce the attack potential offered by such
29 * flooding, revocations must include a proof of work. We use the
30 * set service for efficiently computing the union of revocations of
34 * - optimization: avoid sending revocation back to peer that we got it from;
35 * - optimization: have randomized delay in sending revocations to other peers
36 * to make it rare to traverse each link twice (NSE-style)
40 #include "gnunet_util_lib.h"
41 #include "gnunet_constants.h"
42 #include "gnunet_protocols.h"
43 #include "gnunet_signatures.h"
44 #include "gnunet_statistics_service.h"
45 #include "gnunet_core_service.h"
46 #include "gnunet_revocation_service.h"
47 #include "gnunet_set_service.h"
48 #include "revocation.h"
53 * Per-peer information.
59 * Queue for sending messages to this peer.
61 struct GNUNET_MQ_Handle *mq;
64 * What is the identity of the peer?
66 struct GNUNET_PeerIdentity id;
69 * Tasked used to trigger the set union operation.
71 GNUNET_SCHEDULER_TaskIdentifier transmit_task;
74 * Handle to active set union operation (over revocation sets).
76 struct GNUNET_SET_OperationHandle *so;
82 * Set from all revocations known to us.
84 static struct GNUNET_SET_Handle *revocation_set;
87 * Hash map with all revoked keys, maps the hash of the public key
88 * to the respective `struct RevokeMessage`.
90 static struct GNUNET_CONTAINER_MultiHashMap *revocation_map;
93 * Handle to our current configuration.
95 static const struct GNUNET_CONFIGURATION_Handle *cfg;
98 * Handle to the statistics service.
100 static struct GNUNET_STATISTICS_Handle *stats;
103 * Handle to the core service (for flooding)
105 static struct GNUNET_CORE_Handle *core_api;
108 * Map of all connected peers.
110 static struct GNUNET_CONTAINER_MultiPeerMap *peers;
113 * The peer identity of this peer.
115 static struct GNUNET_PeerIdentity my_identity;
118 * Handle to this serivce's server.
120 static struct GNUNET_SERVER_Handle *srv;
123 * Notification context for convenient sending of replies to the clients.
125 static struct GNUNET_SERVER_NotificationContext *nc;
128 * File handle for the revocation database.
130 static struct GNUNET_DISK_FileHandle *revocation_db;
133 * Handle for us listening to incoming revocation set union requests.
135 static struct GNUNET_SET_ListenHandle *revocation_union_listen_handle;
138 * Amount of work required (W-bit collisions) for REVOCATION proofs, in collision-bits.
140 static unsigned long long revocation_work_required;
143 * Our application ID for set union operations. Must be the
144 * same for all (compatible) peers.
146 static struct GNUNET_HashCode revocation_set_union_app_id;
151 * An revoke message has been received, check that it is well-formed.
153 * @param rm the message to verify
154 * @return #GNUNET_YES if the message is verified
155 * #GNUNET_NO if the key/signature don't verify
158 verify_revoke_message (const struct RevokeMessage *rm)
161 GNUNET_REVOCATION_check_pow (&rm->public_key,
163 (unsigned int) revocation_work_required))
165 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
166 "Proof of work invalid!\n");
171 GNUNET_CRYPTO_ecdsa_verify (GNUNET_SIGNATURE_PURPOSE_REVOCATION,
184 * Handle QUERY message from client.
187 * @param client who sent the message
188 * @param message the message received
191 handle_query_message (void *cls,
192 struct GNUNET_SERVER_Client *client,
193 const struct GNUNET_MessageHeader *message)
195 const struct QueryMessage *qm = (const struct QueryMessage *) message;
196 struct QueryResponseMessage qrm;
197 struct GNUNET_HashCode hc;
200 GNUNET_CRYPTO_hash (&qm->key,
201 sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey),
203 res = GNUNET_CONTAINER_multihashmap_contains (revocation_map, &hc);
204 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
206 ? "Received revocation check for valid key `%s' from client\n"
207 : "Received revocation check for revoked key `%s' from client\n",
209 qrm.header.size = htons (sizeof (struct QueryResponseMessage));
210 qrm.header.type = htons (GNUNET_MESSAGE_TYPE_REVOCATION_QUERY_RESPONSE);
211 qrm.is_valid = htonl ((GNUNET_YES == res) ? GNUNET_NO : GNUNET_YES);
212 GNUNET_SERVER_notification_context_add (nc,
214 GNUNET_SERVER_notification_context_unicast (nc,
218 GNUNET_SERVER_receive_done (client, GNUNET_OK);
223 * Flood the given revocation message to all neighbours.
225 * @param cls the `struct RevokeMessage` to flood
226 * @param target a neighbour
227 * @param value our `struct PeerEntry` for the neighbour
228 * @return #GNUNET_OK (continue to iterate)
232 const struct GNUNET_PeerIdentity *target,
235 const struct RevokeMessage *rm = cls;
236 struct PeerEntry *pe = value;
237 struct GNUNET_MQ_Envelope *e;
238 struct RevokeMessage *cp;
240 e = GNUNET_MQ_msg (cp, GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE);
242 GNUNET_MQ_send (pe->mq, e);
248 * Publicize revocation message. Stores the message locally in the
249 * database and passes it to all connected neighbours (and adds it to
250 * the set for future connections).
252 * @param rm message to publicize
253 * @return #GNUNET_OK on success, #GNUNET_NO if we encountered an error,
254 * #GNUNET_SYSERR if the message was malformed
257 publicize_rm (const struct RevokeMessage *rm)
259 struct RevokeMessage *cp;
260 struct GNUNET_HashCode hc;
261 struct GNUNET_SET_Element e;
263 GNUNET_CRYPTO_hash (&rm->public_key,
264 sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey),
267 GNUNET_CONTAINER_multihashmap_contains (revocation_map,
270 GNUNET_log (GNUNET_ERROR_TYPE_INFO,
271 _("Duplicate revocation received from peer. Ignored.\n"));
275 verify_revoke_message (rm))
278 return GNUNET_SYSERR;
281 if (sizeof (struct RevokeMessage) !=
282 GNUNET_DISK_file_write (revocation_db,
284 sizeof (struct RevokeMessage)))
286 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
291 GNUNET_DISK_file_sync (revocation_db))
293 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
297 /* keep copy in memory */
298 cp = (struct RevokeMessage *) GNUNET_copy_message (&rm->header);
299 GNUNET_break (GNUNET_OK ==
300 GNUNET_CONTAINER_multihashmap_put (revocation_map,
303 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
304 /* add to set for future connections */
305 e.size = htons (rm->header.size);
309 GNUNET_SET_add_element (revocation_set,
316 /* flood to neighbours */
317 GNUNET_CONTAINER_multipeermap_iterate (peers,
325 * Handle REVOKE message from client.
328 * @param client who sent the message
329 * @param message the message received
332 handle_revoke_message (void *cls,
333 struct GNUNET_SERVER_Client *client,
334 const struct GNUNET_MessageHeader *message)
336 const struct RevokeMessage *rm;
337 struct RevocationResponseMessage rrm;
340 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
341 "Received REVOKE message from client\n");
342 rm = (const struct RevokeMessage *) message;
343 if (GNUNET_SYSERR == (ret = publicize_rm (rm)))
346 GNUNET_SERVER_receive_done (client, GNUNET_SYSERR);
349 rrm.header.size = htons (sizeof (struct RevocationResponseMessage));
350 rrm.header.type = htons (GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE_RESPONSE);
351 rrm.is_valid = htonl ((GNUNET_OK == ret) ? GNUNET_NO : GNUNET_YES);
352 GNUNET_SERVER_notification_context_add (nc,
354 GNUNET_SERVER_notification_context_unicast (nc,
358 GNUNET_SERVER_receive_done (client, GNUNET_OK);
363 * Core handler for flooded revocation messages.
365 * @param cls closure unused
366 * @param message message
367 * @param peer peer identity this message is from (ignored)
370 handle_p2p_revoke_message (void *cls,
371 const struct GNUNET_PeerIdentity *peer,
372 const struct GNUNET_MessageHeader *message)
374 const struct RevokeMessage *rm;
376 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
377 "Received REVOKE message from peer\n");
378 rm = (const struct RevokeMessage *) message;
379 GNUNET_break_op (GNUNET_SYSERR != publicize_rm (rm));
386 * Callback for set operation results. Called for each element in the
387 * result set. Each element contains a revocation, which we should
388 * validate and then add to our revocation list (and set).
391 * @param element a result element, only valid if status is #GNUNET_SET_STATUS_OK
392 * @param status see `enum GNUNET_SET_Status`
395 add_revocation (void *cls,
396 const struct GNUNET_SET_Element *element,
397 enum GNUNET_SET_Status status)
399 struct PeerEntry *peer_entry = cls;
400 const struct RevokeMessage *rm;
404 case GNUNET_SET_STATUS_OK:
405 if (element->size != sizeof (struct RevokeMessage))
410 if (0 != element->type)
412 GNUNET_STATISTICS_update (stats,
413 "# unsupported revocations received via set union",
418 (void) handle_p2p_revoke_message (NULL,
421 GNUNET_STATISTICS_update (stats,
422 "# revocation messages received via set union",
425 case GNUNET_SET_STATUS_TIMEOUT:
426 case GNUNET_SET_STATUS_FAILURE:
427 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
428 _("Error computing revocation set union with %s\n"),
429 GNUNET_i2s (&peer_entry->id));
430 peer_entry->so = NULL;
431 GNUNET_STATISTICS_update (stats, "# revocation set unions failed",
434 case GNUNET_SET_STATUS_HALF_DONE:
436 case GNUNET_SET_STATUS_DONE:
437 peer_entry->so = NULL;
438 GNUNET_STATISTICS_update (stats, "# revocation set unions completed",
449 * The timeout for performing the set union has expired,
450 * run the set operation on the revocation certificates.
453 * @param tc scheduler context (unused)
456 transmit_task_cb (void *cls,
457 const struct GNUNET_SCHEDULER_TaskContext *tc)
459 struct PeerEntry *peer_entry = cls;
462 salt = (uint16_t) GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
464 peer_entry->transmit_task = GNUNET_SCHEDULER_NO_TASK;
465 peer_entry->so = GNUNET_SET_prepare (&peer_entry->id,
466 &revocation_set_union_app_id,
468 GNUNET_SET_RESULT_ADDED,
472 GNUNET_SET_commit (peer_entry->so,
475 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
476 _("SET service crashed, terminating revocation service\n"));
477 GNUNET_SCHEDULER_shutdown ();
484 * Method called whenever a peer connects. Sets up the PeerEntry and
485 * schedules the initial revocation set exchange with this peer.
488 * @param peer peer identity this notification is about
491 handle_core_connect (void *cls,
492 const struct GNUNET_PeerIdentity *peer)
494 struct PeerEntry *peer_entry;
495 struct GNUNET_HashCode my_hash;
496 struct GNUNET_HashCode peer_hash;
498 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
499 "Peer `%s' connected to us\n",
501 peer_entry = GNUNET_CONTAINER_multipeermap_get (peers,
503 if (NULL == peer_entry)
505 peer_entry = GNUNET_new (struct PeerEntry);
506 peer_entry->id = *peer;
507 GNUNET_assert (GNUNET_OK ==
508 GNUNET_CONTAINER_multipeermap_put (peers, peer,
510 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
514 GNUNET_assert (NULL == peer_entry->mq);
516 peer_entry->mq = GNUNET_CORE_mq_create (core_api, peer);
517 GNUNET_CRYPTO_hash (&my_identity, sizeof (my_identity), &my_hash);
518 GNUNET_CRYPTO_hash (peer, sizeof (*peer), &peer_hash);
519 if (0 < GNUNET_CRYPTO_hash_cmp (&my_hash,
522 peer_entry->transmit_task =
523 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
527 GNUNET_STATISTICS_update (stats, "# peers connected", 1, GNUNET_NO);
532 * Method called whenever a peer disconnects. Deletes the PeerEntry and cancels
533 * any pending transmission requests to that peer.
536 * @param peer peer identity this notification is about
539 handle_core_disconnect (void *cls,
540 const struct GNUNET_PeerIdentity *peer)
542 struct PeerEntry *pos;
544 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
545 "Peer `%s' disconnected from us\n",
547 pos = GNUNET_CONTAINER_multipeermap_get (peers, peer);
553 GNUNET_assert (GNUNET_YES ==
554 GNUNET_CONTAINER_multipeermap_remove (peers, peer,
556 GNUNET_MQ_destroy (pos->mq);
557 if (pos->transmit_task != GNUNET_SCHEDULER_NO_TASK)
559 GNUNET_SCHEDULER_cancel (pos->transmit_task);
560 pos->transmit_task = GNUNET_SCHEDULER_NO_TASK;
564 GNUNET_SET_operation_cancel (pos->so);
568 GNUNET_STATISTICS_update (stats, "# peers connected", -1, GNUNET_NO);
573 * Free all values in a hash map.
577 * @param value value to free
578 * @return #GNUNET_OK (continue to iterate)
581 free_entry (void *cls,
582 const struct GNUNET_HashCode *key,
591 * Task run during shutdown.
597 shutdown_task (void *cls,
598 const struct GNUNET_SCHEDULER_TaskContext *tc)
600 if (NULL != revocation_set)
602 GNUNET_SET_destroy (revocation_set);
603 revocation_set = NULL;
605 if (NULL != revocation_union_listen_handle)
607 GNUNET_SET_listen_cancel (revocation_union_listen_handle);
608 revocation_union_listen_handle = NULL;
610 if (NULL != core_api)
612 GNUNET_CORE_disconnect (core_api);
617 GNUNET_STATISTICS_destroy (stats, GNUNET_NO);
622 GNUNET_CONTAINER_multipeermap_destroy (peers);
627 GNUNET_SERVER_notification_context_destroy (nc);
630 if (NULL != revocation_db)
632 GNUNET_DISK_file_close (revocation_db);
633 revocation_db = NULL;
635 GNUNET_CONTAINER_multihashmap_iterate (revocation_map,
638 GNUNET_CONTAINER_multihashmap_destroy (revocation_map);
643 * Called on core init/fail.
645 * @param cls service closure
646 * @param identity the public identity of this peer
649 core_init (void *cls,
650 const struct GNUNET_PeerIdentity *identity)
652 if (NULL == identity)
654 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
655 "Connection to core FAILED!\n");
656 GNUNET_SCHEDULER_shutdown ();
659 my_identity = *identity;
664 * Called when another peer wants to do a set operation with the
665 * local peer. If a listen error occurs, the 'request' is NULL.
668 * @param other_peer the other peer
669 * @param context_msg message with application specific information from
671 * @param request request from the other peer (never NULL), use GNUNET_SET_accept()
672 * to accept it, otherwise the request will be refused
673 * Note that we can't just return value from the listen callback,
674 * as it is also necessary to specify the set we want to do the
675 * operation with, whith sometimes can be derived from the context
676 * message. It's necessary to specify the timeout.
679 handle_revocation_union_request (void *cls,
680 const struct GNUNET_PeerIdentity *other_peer,
681 const struct GNUNET_MessageHeader *context_msg,
682 struct GNUNET_SET_Request *request)
684 struct PeerEntry *peer_entry;
691 peer_entry = GNUNET_CONTAINER_multipeermap_get (peers,
693 if (NULL == peer_entry)
695 peer_entry = GNUNET_new (struct PeerEntry);
696 peer_entry->id = *other_peer;
697 GNUNET_assert (GNUNET_OK ==
698 GNUNET_CONTAINER_multipeermap_put (peers, other_peer,
700 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
702 peer_entry->so = GNUNET_SET_accept (request,
703 GNUNET_SET_RESULT_ADDED,
710 * Handle network size estimate clients.
713 * @param server the initialized server
714 * @param c configuration to use
718 struct GNUNET_SERVER_Handle *server,
719 const struct GNUNET_CONFIGURATION_Handle *c)
721 static const struct GNUNET_SERVER_MessageHandler handlers[] = {
722 {&handle_query_message, NULL, GNUNET_MESSAGE_TYPE_REVOCATION_QUERY,
723 sizeof (struct QueryMessage)},
724 {&handle_revoke_message, NULL, GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE,
725 sizeof (struct RevokeMessage)},
728 static const struct GNUNET_CORE_MessageHandler core_handlers[] = {
729 {&handle_p2p_revoke_message, GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE,
730 sizeof (struct RevokeMessage)},
735 struct RevokeMessage *rm;
736 struct GNUNET_HashCode hc;
739 GNUNET_CONFIGURATION_get_value_filename (c,
744 GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
747 GNUNET_SCHEDULER_shutdown ();
752 revocation_map = GNUNET_CONTAINER_multihashmap_create (16, GNUNET_NO);
753 nc = GNUNET_SERVER_notification_context_create (server, 1);
755 GNUNET_CONFIGURATION_get_value_number (cfg, "REVOCATION", "WORKBITS",
756 &revocation_work_required))
758 GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
761 GNUNET_SCHEDULER_shutdown ();
765 if (revocation_work_required >= sizeof (struct GNUNET_HashCode) * 8)
767 GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
770 _("Value is too large.\n"));
771 GNUNET_SCHEDULER_shutdown ();
775 revocation_set = GNUNET_SET_create (cfg,
776 GNUNET_SET_OPERATION_UNION);
777 revocation_union_listen_handle = GNUNET_SET_listen (cfg,
778 GNUNET_SET_OPERATION_UNION,
779 &revocation_set_union_app_id,
780 &handle_revocation_union_request,
782 revocation_db = GNUNET_DISK_file_open (fn,
783 GNUNET_DISK_OPEN_READWRITE |
784 GNUNET_DISK_OPEN_CREATE,
785 GNUNET_DISK_PERM_USER_READ | GNUNET_DISK_PERM_USER_WRITE |
786 GNUNET_DISK_PERM_GROUP_READ |
787 GNUNET_DISK_PERM_OTHER_READ);
788 if (NULL == revocation_db)
790 GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
793 _("Could not open revocation database file!"));
794 GNUNET_SCHEDULER_shutdown ();
799 GNUNET_DISK_file_size (fn, &left, GNUNET_YES, GNUNET_YES))
801 while (left > sizeof (struct RevokeMessage))
803 rm = GNUNET_new (struct RevokeMessage);
804 if (sizeof (struct RevokeMessage) !=
805 GNUNET_DISK_file_read (revocation_db,
807 sizeof (struct RevokeMessage)))
809 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
813 GNUNET_SCHEDULER_shutdown ();
817 GNUNET_break (0 == ntohl (rm->reserved));
818 GNUNET_CRYPTO_hash (&rm->public_key,
819 sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey),
821 GNUNET_break (GNUNET_OK ==
822 GNUNET_CONTAINER_multihashmap_put (revocation_map,
825 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
829 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &shutdown_task,
831 peers = GNUNET_CONTAINER_multipeermap_create (128, GNUNET_NO);
832 GNUNET_SERVER_add_handlers (srv, handlers);
833 /* Connect to core service and register core handlers */
834 core_api = GNUNET_CORE_connect (cfg, /* Main configuration */
835 NULL, /* Closure passed to functions */
836 &core_init, /* Call core_init once connected */
837 &handle_core_connect, /* Handle connects */
838 &handle_core_disconnect, /* Handle disconnects */
839 NULL, /* Don't want notified about all incoming messages */
840 GNUNET_NO, /* For header only inbound notification */
841 NULL, /* Don't want notified about all outbound messages */
842 GNUNET_NO, /* For header only outbound notification */
843 core_handlers); /* Register these handlers */
844 if (NULL == core_api)
846 GNUNET_SCHEDULER_shutdown ();
849 stats = GNUNET_STATISTICS_create ("revocation", cfg);
854 * The main function for the network size estimation service.
856 * @param argc number of arguments from the command line
857 * @param argv command line arguments
858 * @return 0 ok, 1 on error
864 GNUNET_CRYPTO_hash ("revocation-set-union-application-id",
865 strlen ("revocation-set-union-application-id"),
866 &revocation_set_union_app_id);
868 GNUNET_SERVICE_run (argc, argv, "revocation", GNUNET_SERVICE_OPTION_NONE,
869 &run, NULL)) ? 0 : 1;
877 * MINIMIZE heap size (way below 128k) since this process doesn't need much.
879 void __attribute__ ((constructor))
880 GNUNET_ARM_memory_init ()
882 mallopt (M_TRIM_THRESHOLD, 4 * 1024);
883 mallopt (M_TOP_PAD, 1 * 1024);
890 /* end of gnunet-service-revocation.c */