2 This file is part of GNUnet.
3 Copyright (C) 2013, 2014 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.
15 You should have received a copy of the GNU General Public Licerevocation
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 struct GNUNET_SCHEDULER_Task * 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,
205 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
207 ? "Received revocation check for valid key `%s' from client\n"
208 : "Received revocation check for revoked key `%s' from client\n",
210 qrm.header.size = htons (sizeof (struct QueryResponseMessage));
211 qrm.header.type = htons (GNUNET_MESSAGE_TYPE_REVOCATION_QUERY_RESPONSE);
212 qrm.is_valid = htonl ((GNUNET_YES == res) ? GNUNET_NO : GNUNET_YES);
213 GNUNET_SERVER_notification_context_add (nc,
215 GNUNET_SERVER_notification_context_unicast (nc,
219 GNUNET_SERVER_receive_done (client,
225 * Flood the given revocation message to all neighbours.
227 * @param cls the `struct RevokeMessage` to flood
228 * @param target a neighbour
229 * @param value our `struct PeerEntry` for the neighbour
230 * @return #GNUNET_OK (continue to iterate)
234 const struct GNUNET_PeerIdentity *target,
237 const struct RevokeMessage *rm = cls;
238 struct PeerEntry *pe = value;
239 struct GNUNET_MQ_Envelope *e;
240 struct RevokeMessage *cp;
242 e = GNUNET_MQ_msg (cp,
243 GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE);
245 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
246 "Flooding revocation to `%s'\n",
247 GNUNET_i2s (target));
248 GNUNET_MQ_send (pe->mq,
255 * Publicize revocation message. Stores the message locally in the
256 * database and passes it to all connected neighbours (and adds it to
257 * the set for future connections).
259 * @param rm message to publicize
260 * @return #GNUNET_OK on success, #GNUNET_NO if we encountered an error,
261 * #GNUNET_SYSERR if the message was malformed
264 publicize_rm (const struct RevokeMessage *rm)
266 struct RevokeMessage *cp;
267 struct GNUNET_HashCode hc;
268 struct GNUNET_SET_Element e;
270 GNUNET_CRYPTO_hash (&rm->public_key,
271 sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey),
274 GNUNET_CONTAINER_multihashmap_contains (revocation_map,
277 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
278 "Duplicate revocation received from peer. Ignored.\n");
282 verify_revoke_message (rm))
285 return GNUNET_SYSERR;
288 if (sizeof (struct RevokeMessage) !=
289 GNUNET_DISK_file_write (revocation_db,
291 sizeof (struct RevokeMessage)))
293 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
298 GNUNET_DISK_file_sync (revocation_db))
300 GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR,
304 /* keep copy in memory */
305 cp = (struct RevokeMessage *) GNUNET_copy_message (&rm->header);
306 GNUNET_break (GNUNET_OK ==
307 GNUNET_CONTAINER_multihashmap_put (revocation_map,
310 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
311 /* add to set for future connections */
312 e.size = htons (rm->header.size);
316 GNUNET_SET_add_element (revocation_set,
326 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
327 "Added revocation info to SET\n");
329 /* flood to neighbours */
330 GNUNET_CONTAINER_multipeermap_iterate (peers,
338 * Handle REVOKE message from client.
341 * @param client who sent the message
342 * @param message the message received
345 handle_revoke_message (void *cls,
346 struct GNUNET_SERVER_Client *client,
347 const struct GNUNET_MessageHeader *message)
349 const struct RevokeMessage *rm;
350 struct RevocationResponseMessage rrm;
353 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
354 "Received REVOKE message from client\n");
355 rm = (const struct RevokeMessage *) message;
356 if (GNUNET_SYSERR == (ret = publicize_rm (rm)))
359 GNUNET_SERVER_receive_done (client,
363 rrm.header.size = htons (sizeof (struct RevocationResponseMessage));
364 rrm.header.type = htons (GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE_RESPONSE);
365 rrm.is_valid = htonl ((GNUNET_OK == ret) ? GNUNET_NO : GNUNET_YES);
366 GNUNET_SERVER_notification_context_add (nc,
368 GNUNET_SERVER_notification_context_unicast (nc,
372 GNUNET_SERVER_receive_done (client,
378 * Core handler for flooded revocation messages.
380 * @param cls closure unused
381 * @param message message
382 * @param peer peer identity this message is from (ignored)
385 handle_p2p_revoke_message (void *cls,
386 const struct GNUNET_PeerIdentity *peer,
387 const struct GNUNET_MessageHeader *message)
389 const struct RevokeMessage *rm;
391 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
392 "Received REVOKE message from peer\n");
393 rm = (const struct RevokeMessage *) message;
394 GNUNET_break_op (GNUNET_SYSERR != publicize_rm (rm));
400 * Callback for set operation results. Called for each element in the
401 * result set. Each element contains a revocation, which we should
402 * validate and then add to our revocation list (and set).
405 * @param element a result element, only valid if status is #GNUNET_SET_STATUS_OK
406 * @param status see `enum GNUNET_SET_Status`
409 add_revocation (void *cls,
410 const struct GNUNET_SET_Element *element,
411 enum GNUNET_SET_Status status)
413 struct PeerEntry *peer_entry = cls;
414 const struct RevokeMessage *rm;
418 case GNUNET_SET_STATUS_OK:
419 if (element->size != sizeof (struct RevokeMessage))
424 if (0 != element->element_type)
426 GNUNET_STATISTICS_update (stats,
427 gettext_noop ("# unsupported revocations received via set union"),
432 (void) handle_p2p_revoke_message (NULL,
435 GNUNET_STATISTICS_update (stats,
436 gettext_noop ("# revocation messages received via set union"),
439 case GNUNET_SET_STATUS_FAILURE:
440 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
441 _("Error computing revocation set union with %s\n"),
442 GNUNET_i2s (&peer_entry->id));
443 peer_entry->so = NULL;
444 GNUNET_STATISTICS_update (stats,
445 gettext_noop ("# revocation set unions failed"),
449 case GNUNET_SET_STATUS_HALF_DONE:
451 case GNUNET_SET_STATUS_DONE:
452 peer_entry->so = NULL;
453 GNUNET_STATISTICS_update (stats,
454 gettext_noop ("# revocation set unions completed"),
466 * The timeout for performing the set union has expired,
467 * run the set operation on the revocation certificates.
470 * @param tc scheduler context (unused)
473 transmit_task_cb (void *cls,
474 const struct GNUNET_SCHEDULER_TaskContext *tc)
476 struct PeerEntry *peer_entry = cls;
478 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
479 "Starting set exchange with peer `%s'\n",
480 GNUNET_i2s (&peer_entry->id));
481 peer_entry->transmit_task = NULL;
482 peer_entry->so = GNUNET_SET_prepare (&peer_entry->id,
483 &revocation_set_union_app_id,
485 GNUNET_SET_RESULT_ADDED,
489 GNUNET_SET_commit (peer_entry->so,
492 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
493 _("SET service crashed, terminating revocation service\n"));
494 GNUNET_SCHEDULER_shutdown ();
501 * Method called whenever a peer connects. Sets up the PeerEntry and
502 * schedules the initial revocation set exchange with this peer.
505 * @param peer peer identity this notification is about
508 handle_core_connect (void *cls,
509 const struct GNUNET_PeerIdentity *peer)
511 struct PeerEntry *peer_entry;
512 struct GNUNET_HashCode my_hash;
513 struct GNUNET_HashCode peer_hash;
515 if (0 == memcmp (peer,
517 sizeof (my_identity)))
522 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
523 "Peer `%s' connected to us\n",
525 GNUNET_STATISTICS_update (stats,
529 peer_entry = GNUNET_CONTAINER_multipeermap_get (peers,
531 if (NULL != peer_entry)
533 /* This can happen if "core"'s notification is a tad late
534 and CADET+SET were faster and already produced a
535 #handle_revocation_union_request() for us to deal
536 with. This should be rare, but isn't impossible. */
539 peer_entry = GNUNET_new (struct PeerEntry);
540 peer_entry->id = *peer;
541 GNUNET_assert (GNUNET_OK ==
542 GNUNET_CONTAINER_multipeermap_put (peers,
545 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
546 peer_entry->mq = GNUNET_CORE_mq_create (core_api, peer);
547 GNUNET_CRYPTO_hash (&my_identity,
548 sizeof (my_identity),
550 GNUNET_CRYPTO_hash (peer,
553 if (0 < GNUNET_CRYPTO_hash_cmp (&my_hash,
556 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
557 "Starting SET operation with peer `%s'\n",
559 peer_entry->transmit_task =
560 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS,
568 * Method called whenever a peer disconnects. Deletes the PeerEntry and cancels
569 * any pending transmission requests to that peer.
572 * @param peer peer identity this notification is about
575 handle_core_disconnect (void *cls,
576 const struct GNUNET_PeerIdentity *peer)
578 struct PeerEntry *pos;
580 if (0 == memcmp (peer,
582 sizeof (my_identity)))
587 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
588 "Peer `%s' disconnected from us\n",
590 pos = GNUNET_CONTAINER_multipeermap_get (peers,
592 GNUNET_assert (NULL != pos);
593 GNUNET_assert (GNUNET_YES ==
594 GNUNET_CONTAINER_multipeermap_remove (peers,
597 GNUNET_MQ_destroy (pos->mq);
598 if (NULL != pos->transmit_task)
600 GNUNET_SCHEDULER_cancel (pos->transmit_task);
601 pos->transmit_task = NULL;
605 GNUNET_SET_operation_cancel (pos->so);
609 GNUNET_STATISTICS_update (stats,
617 * Free all values in a hash map.
621 * @param value value to free
622 * @return #GNUNET_OK (continue to iterate)
625 free_entry (void *cls,
626 const struct GNUNET_HashCode *key,
635 * Task run during shutdown.
641 shutdown_task (void *cls,
642 const struct GNUNET_SCHEDULER_TaskContext *tc)
644 if (NULL != revocation_set)
646 GNUNET_SET_destroy (revocation_set);
647 revocation_set = NULL;
649 if (NULL != revocation_union_listen_handle)
651 GNUNET_SET_listen_cancel (revocation_union_listen_handle);
652 revocation_union_listen_handle = NULL;
654 if (NULL != core_api)
656 GNUNET_CORE_disconnect (core_api);
661 GNUNET_STATISTICS_destroy (stats, GNUNET_NO);
666 GNUNET_CONTAINER_multipeermap_destroy (peers);
671 GNUNET_SERVER_notification_context_destroy (nc);
674 if (NULL != revocation_db)
676 GNUNET_DISK_file_close (revocation_db);
677 revocation_db = NULL;
679 GNUNET_CONTAINER_multihashmap_iterate (revocation_map,
682 GNUNET_CONTAINER_multihashmap_destroy (revocation_map);
687 * Called on core init/fail.
689 * @param cls service closure
690 * @param identity the public identity of this peer
693 core_init (void *cls,
694 const struct GNUNET_PeerIdentity *identity)
696 if (NULL == identity)
698 GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
699 "Connection to core FAILED!\n");
700 GNUNET_SCHEDULER_shutdown ();
703 my_identity = *identity;
708 * Called when another peer wants to do a set operation with the
709 * local peer. If a listen error occurs, the 'request' is NULL.
712 * @param other_peer the other peer
713 * @param context_msg message with application specific information from
715 * @param request request from the other peer (never NULL), use GNUNET_SET_accept()
716 * to accept it, otherwise the request will be refused
717 * Note that we can't just return value from the listen callback,
718 * as it is also necessary to specify the set we want to do the
719 * operation with, whith sometimes can be derived from the context
720 * message. It's necessary to specify the timeout.
723 handle_revocation_union_request (void *cls,
724 const struct GNUNET_PeerIdentity *other_peer,
725 const struct GNUNET_MessageHeader *context_msg,
726 struct GNUNET_SET_Request *request)
728 struct PeerEntry *peer_entry;
735 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
736 "Received set exchange request from peer `%s'\n",
737 GNUNET_i2s (other_peer));
738 peer_entry = GNUNET_CONTAINER_multipeermap_get (peers,
740 if (NULL == peer_entry)
742 peer_entry = GNUNET_new (struct PeerEntry);
743 peer_entry->id = *other_peer;
744 GNUNET_assert (GNUNET_OK ==
745 GNUNET_CONTAINER_multipeermap_put (peers,
748 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
750 peer_entry->so = GNUNET_SET_accept (request,
751 GNUNET_SET_RESULT_ADDED,
755 GNUNET_SET_commit (peer_entry->so,
758 GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
759 _("SET service crashed, terminating revocation service\n"));
760 GNUNET_SCHEDULER_shutdown ();
767 * Handle network size estimate clients.
770 * @param server the initialized server
771 * @param c configuration to use
775 struct GNUNET_SERVER_Handle *server,
776 const struct GNUNET_CONFIGURATION_Handle *c)
778 static const struct GNUNET_SERVER_MessageHandler handlers[] = {
779 {&handle_query_message, NULL, GNUNET_MESSAGE_TYPE_REVOCATION_QUERY,
780 sizeof (struct QueryMessage)},
781 {&handle_revoke_message, NULL, GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE,
782 sizeof (struct RevokeMessage)},
785 static const struct GNUNET_CORE_MessageHandler core_handlers[] = {
786 {&handle_p2p_revoke_message, GNUNET_MESSAGE_TYPE_REVOCATION_REVOKE,
787 sizeof (struct RevokeMessage)},
792 struct RevokeMessage *rm;
793 struct GNUNET_HashCode hc;
796 GNUNET_CONFIGURATION_get_value_filename (c,
801 GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
804 GNUNET_SCHEDULER_shutdown ();
809 revocation_map = GNUNET_CONTAINER_multihashmap_create (16, GNUNET_NO);
810 nc = GNUNET_SERVER_notification_context_create (server, 1);
812 GNUNET_CONFIGURATION_get_value_number (cfg, "REVOCATION", "WORKBITS",
813 &revocation_work_required))
815 GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
818 GNUNET_SCHEDULER_shutdown ();
822 if (revocation_work_required >= sizeof (struct GNUNET_HashCode) * 8)
824 GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
827 _("Value is too large.\n"));
828 GNUNET_SCHEDULER_shutdown ();
832 revocation_set = GNUNET_SET_create (cfg,
833 GNUNET_SET_OPERATION_UNION);
834 revocation_union_listen_handle
835 = GNUNET_SET_listen (cfg,
836 GNUNET_SET_OPERATION_UNION,
837 &revocation_set_union_app_id,
838 &handle_revocation_union_request,
840 revocation_db = GNUNET_DISK_file_open (fn,
841 GNUNET_DISK_OPEN_READWRITE |
842 GNUNET_DISK_OPEN_CREATE,
843 GNUNET_DISK_PERM_USER_READ | GNUNET_DISK_PERM_USER_WRITE |
844 GNUNET_DISK_PERM_GROUP_READ |
845 GNUNET_DISK_PERM_OTHER_READ);
846 if (NULL == revocation_db)
848 GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
851 _("Could not open revocation database file!"));
852 GNUNET_SCHEDULER_shutdown ();
857 GNUNET_DISK_file_size (fn, &left, GNUNET_YES, GNUNET_YES))
859 while (left > sizeof (struct RevokeMessage))
861 rm = GNUNET_new (struct RevokeMessage);
862 if (sizeof (struct RevokeMessage) !=
863 GNUNET_DISK_file_read (revocation_db,
865 sizeof (struct RevokeMessage)))
867 GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_ERROR,
871 GNUNET_SCHEDULER_shutdown ();
875 GNUNET_break (0 == ntohl (rm->reserved));
876 GNUNET_CRYPTO_hash (&rm->public_key,
877 sizeof (struct GNUNET_CRYPTO_EcdsaPublicKey),
879 GNUNET_break (GNUNET_OK ==
880 GNUNET_CONTAINER_multihashmap_put (revocation_map,
883 GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
887 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
890 peers = GNUNET_CONTAINER_multipeermap_create (128,
892 GNUNET_SERVER_add_handlers (srv, handlers);
893 /* Connect to core service and register core handlers */
894 core_api = GNUNET_CORE_connect (cfg, /* Main configuration */
895 NULL, /* Closure passed to functions */
896 &core_init, /* Call core_init once connected */
897 &handle_core_connect, /* Handle connects */
898 &handle_core_disconnect, /* Handle disconnects */
899 NULL, /* Don't want notified about all incoming messages */
900 GNUNET_NO, /* For header only inbound notification */
901 NULL, /* Don't want notified about all outbound messages */
902 GNUNET_NO, /* For header only outbound notification */
903 core_handlers); /* Register these handlers */
904 if (NULL == core_api)
906 GNUNET_SCHEDULER_shutdown ();
909 stats = GNUNET_STATISTICS_create ("revocation", cfg);
914 * The main function for the network size estimation service.
916 * @param argc number of arguments from the command line
917 * @param argv command line arguments
918 * @return 0 ok, 1 on error
924 GNUNET_CRYPTO_hash ("revocation-set-union-application-id",
925 strlen ("revocation-set-union-application-id"),
926 &revocation_set_union_app_id);
928 GNUNET_SERVICE_run (argc,
931 GNUNET_SERVICE_OPTION_NONE,
932 &run, NULL)) ? 0 : 1;
941 * MINIMIZE heap size (way below 128k) since this process doesn't need much.
943 void __attribute__ ((constructor))
944 GNUNET_ARM_memory_init ()
946 mallopt (M_TRIM_THRESHOLD, 4 * 1024);
947 mallopt (M_TOP_PAD, 1 * 1024);
953 /* end of gnunet-service-revocation.c */