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hs: Move and improve the service pruning code

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First, this commit moves the code used to prune the service list when
reloading Tor (HUP signal for instance) to a function from
rend_config_services().

Second, fix bug #21054, improve the code by using the newly added
circuit_get_next_service_intro_circ() function instead of poking at the global
list directly and add _many_ more comments.

Fixes #21054.

Signed-off-by: David Goulet <dgoulet@torproject.org>
This commit is contained in:
David Goulet 2016-12-21 13:35:22 -05:00
parent 8a05e1a5d2
commit 36b5ca2c8b
2 changed files with 99 additions and 78 deletions
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5
changes/bug21054 Normal file
View file

@ -0,0 +1,5 @@
o Minor bugfixes (hidden service):
- Fix the config reload pruning of old vs new services so it actually
works when both ephemeral and non ephemeral services were configured
which lead to a BUG() stacktrace. Close #21054; Bugfix on
tor-0.3.0.1-alpha.

172
src/or/rendservice.c
View file

@ -542,6 +542,95 @@ rend_service_check_dir_and_add(smartlist_t *service_list,
return rend_add_service(s_list, service);
}
/* If this is a reload and there were hidden services configured before,
* keep the introduction points that are still needed and close the
* other ones. */
static void
prune_services_on_reload(smartlist_t *old_service_list,
smartlist_t *new_service_list)
{
origin_circuit_t *ocirc = NULL;
smartlist_t *surviving_services = NULL;
tor_assert(old_service_list);
tor_assert(new_service_list);
/* This contains all _existing_ services that survives the relaod that is
* that haven't been removed from the configuration. The difference between
* this list and the new service list is that the new list can possibly
* contain newly configured service that have no introduction points opened
* yet nor key material loaded or generated. */
surviving_services = smartlist_new();
/* Preserve the existing ephemeral services.
*
* This is the ephemeral service equivalent of the "Copy introduction
* points to new services" block, except there's no copy required since
* the service structure isn't regenerated.
*
* After this is done, all ephemeral services will be:
* * Removed from old_service_list, so the equivalent non-ephemeral code
* will not attempt to preserve them.
* * Added to the new_service_list (that previously only had the
* services listed in the configuration).
* * Added to surviving_services, which is the list of services that
* will NOT have their intro point closed.
*/
SMARTLIST_FOREACH_BEGIN(old_service_list, rend_service_t *, old) {
if (rend_service_is_ephemeral(old)) {
SMARTLIST_DEL_CURRENT(old_service_list, old);
smartlist_add(surviving_services, old);
smartlist_add(new_service_list, old);
}
} SMARTLIST_FOREACH_END(old);
/* Copy introduction points to new services. This is O(n^2), but it's only
* called on reconfigure, so it's ok performance wise. */
SMARTLIST_FOREACH_BEGIN(new_service_list, rend_service_t *, new) {
SMARTLIST_FOREACH_BEGIN(old_service_list, rend_service_t *, old) {
/* Skip ephemeral services as we only want to copy introduction points
* from current services to newly configured one that already exists.
* The same directory means it's the same service. */
if (rend_service_is_ephemeral(new) || rend_service_is_ephemeral(old) ||
strcmp(old->directory, new->directory)) {
continue;
}
smartlist_add_all(new->intro_nodes, old->intro_nodes);
smartlist_clear(old->intro_nodes);
smartlist_add_all(new->expiring_nodes, old->expiring_nodes);
smartlist_clear(old->expiring_nodes);
/* This regular service will survive the closing IPs step after. */
smartlist_add(surviving_services, old);
break;
} SMARTLIST_FOREACH_END(old);
} SMARTLIST_FOREACH_END(new);
/* For every service introduction circuit we can find, see if we have a
* matching surviving configured service. If not, close the circuit. */
while ((ocirc = circuit_get_next_service_intro_circ(ocirc))) {
int keep_it = 0;
tor_assert(ocirc->rend_data);
SMARTLIST_FOREACH_BEGIN(surviving_services, const rend_service_t *, s) {
if (rend_circuit_pk_digest_eq(ocirc, (uint8_t *) s->pk_digest)) {
/* Keep this circuit as we have a matching configured service. */
keep_it = 1;
break;
}
} SMARTLIST_FOREACH_END(s);
if (keep_it) {
continue;
}
log_info(LD_REND, "Closing intro point %s for service %s.",
safe_str_client(extend_info_describe(
ocirc->build_state->chosen_exit)),
safe_str_client(rend_data_get_address(ocirc->rend_data)));
/* Reason is FINISHED because service has been removed and thus the
* circuit is considered old/uneeded. */
circuit_mark_for_close(TO_CIRCUIT(ocirc), END_CIRC_REASON_FINISHED);
}
smartlist_free(surviving_services);
}
/** Set up rend_service_list, based on the values of HiddenServiceDir and
* HiddenServicePort in <b>options</b>. Return 0 on success and -1 on
* failure. (If <b>validate_only</b> is set, parse, warn and return as
@ -807,84 +896,11 @@ rend_config_services(const or_options_t *options, int validate_only)
* keep the introduction points that are still needed and close the
* other ones. */
if (old_service_list && !validate_only) {
smartlist_t *surviving_services = smartlist_new();
/* Preserve the existing ephemeral services.
*
* This is the ephemeral service equivalent of the "Copy introduction
* points to new services" block, except there's no copy required since
* the service structure isn't regenerated.
*
* After this is done, all ephemeral services will be:
* * Removed from old_service_list, so the equivalent non-ephemeral code
* will not attempt to preserve them.
* * Added to the new rend_service_list (that previously only had the
* services listed in the configuration).
* * Added to surviving_services, which is the list of services that
* will NOT have their intro point closed.
*/
SMARTLIST_FOREACH(old_service_list, rend_service_t *, old, {
if (rend_service_is_ephemeral(old)) {
SMARTLIST_DEL_CURRENT(old_service_list, old);
smartlist_add(surviving_services, old);
smartlist_add(rend_service_list, old);
}
});
/* Copy introduction points to new services. */
/* XXXX This is O(n^2), but it's only called on reconfigure, so it's
* probably ok? */
SMARTLIST_FOREACH_BEGIN(rend_service_list, rend_service_t *, new) {
SMARTLIST_FOREACH_BEGIN(old_service_list, rend_service_t *, old) {
if (BUG(rend_service_is_ephemeral(new)) ||
BUG(rend_service_is_ephemeral(old))) {
continue;
}
if (BUG(!new->directory) || BUG(!old->directory) ||
strcmp(old->directory, new->directory)) {
continue;
}
smartlist_add_all(new->intro_nodes, old->intro_nodes);
smartlist_clear(old->intro_nodes);
smartlist_add_all(new->expiring_nodes, old->expiring_nodes);
smartlist_clear(old->expiring_nodes);
smartlist_add(surviving_services, old);
break;
} SMARTLIST_FOREACH_END(old);
} SMARTLIST_FOREACH_END(new);
/* Close introduction circuits of services we don't serve anymore. */
/* XXXX it would be nicer if we had a nicer abstraction to use here,
* so we could just iterate over the list of services to close, but
* once again, this isn't critical-path code. */
SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) {
if (!circ->marked_for_close &&
circ->state == CIRCUIT_STATE_OPEN &&
(circ->purpose == CIRCUIT_PURPOSE_S_ESTABLISH_INTRO ||
circ->purpose == CIRCUIT_PURPOSE_S_INTRO)) {
origin_circuit_t *oc = TO_ORIGIN_CIRCUIT(circ);
int keep_it = 0;
tor_assert(oc->rend_data);
SMARTLIST_FOREACH(surviving_services, rend_service_t *, ptr, {
if (rend_circuit_pk_digest_eq(oc, (uint8_t *) ptr->pk_digest)) {
keep_it = 1;
break;
}
});
if (keep_it)
continue;
log_info(LD_REND, "Closing intro point %s for service %s.",
safe_str_client(extend_info_describe(
oc->build_state->chosen_exit)),
rend_data_get_address(oc->rend_data));
circuit_mark_for_close(circ, END_CIRC_REASON_FINISHED);
/* XXXX Is there another reason we should use here? */
}
}
SMARTLIST_FOREACH_END(circ);
smartlist_free(surviving_services);
SMARTLIST_FOREACH(old_service_list, rend_service_t *, ptr,
rend_service_free(ptr));
prune_services_on_reload(old_service_list, rend_service_list);
/* Every remaining service in the old list have been removed from the
* configuration so clean them up safely. */
SMARTLIST_FOREACH(old_service_list, rend_service_t *, s,
rend_service_free(s));
smartlist_free(old_service_list);
}