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-rw-r--r--changes/ticket4065210
-rw-r--r--doc/man/tor.1.txt26
-rw-r--r--src/feature/dirauth/dirauth_config.c5
-rw-r--r--src/feature/dirauth/dirauth_options.inc25
-rw-r--r--src/feature/dirauth/voteflags.c56
5 files changed, 95 insertions, 27 deletions
diff --git a/changes/ticket40652 b/changes/ticket40652
new file mode 100644
index 0000000000..ff9f4d0591
--- /dev/null
+++ b/changes/ticket40652
@@ -0,0 +1,10 @@
+ o Minor features (dirauth):
+ - Add an AuthDirVoteGuard torrc option that can allow authorities to
+ assign the Guard flag to the given fingerprints/country code/IPs. This
+ is a needed feature mostly for defense purposes in case a DoS hits the
+ network and relay start losing the Guard flags too fast.
+ - Make UPTIME_TO_GUARANTEE_STABLE, MTBF_TO_GUARANTEE_STABLE,
+ TIME_KNOWN_TO_GUARANTEE_FAMILIAR WFU_TO_GUARANTEE_GUARD tunable from
+ torrc.
+ - Add a torrc option to control the Guard flag bandwidth threshold
+ percentile. Closes ticket 40652.
diff --git a/doc/man/tor.1.txt b/doc/man/tor.1.txt
index 59a9ddc714..712988fa5a 100644
--- a/doc/man/tor.1.txt
+++ b/doc/man/tor.1.txt
@@ -3229,6 +3229,32 @@ on the public Tor network.
If set to 0, we vote Running for every relay, and don't perform
these tests. (Default: 1)
+[[AuthDirVoteGuard]] **AuthDirVoteGuard** __node__,__node__,__...__::
+ A list of identity fingerprints or country codes or address patterns of
+ nodes to vote Guard for regardless of their uptime and bandwidth. See
+ <<ExcludeNodes,ExcludeNodes>> for more information on how to specify nodes.
+
+[[AuthDirVoteGuardBwThresholdFraction]] **AuthDirVoteGuardBwThresholdFraction** __FRACTION__::
+ The Guard flag bandwidth performance threshold fraction that is the
+ fraction representing who gets the Guard flag out of all measured
+ bandwidth. (Default: 0.75)
+
+[[AuthDirVoteGuardGuaranteeTimeKnown]] **AuthDirVoteGuardGuaranteeTimeKnown** __N__ **seconds**|**minutes**|**hours**|**days**|**weeks**::
+ A relay with at least this much weighted time known can be considered
+ familiar enough to be a guard. (Default: 8 days)
+
+[[AuthDirVoteGuardGuaranteeWFU]] **AuthDirVoteGuardGuaranteeWFU** __FRACTION__::
+ A level of weighted fractional uptime (WFU) is that is sufficient to be a
+ Guard. (Default: 0.98)
+
+[[AuthDirVoteStableGuaranteeMinUptime]] **AuthDirVoteStableGuaranteeMinUptime** __N__ **seconds**|**minutes**|**hours**|**days**|**weeks**::
+ If a relay's uptime is at least this value, then it is always considered
+ stable, regardless of the rest of the network. (Default: 30 days)
+
+[[AuthDirVoteStableGuaranteeMTBF]] **AuthDirVoteStableGuaranteeMTBF** __N__ **seconds**|**minutes**|**hours**|**days**|**weeks**::
+ If a relay's mean time between failures (MTBF) is least this value, then
+ it will always be considered stable. (Default: 5 days)
+
[[BridgePassword]] **BridgePassword** __Password__::
If set, contains an HTTP authenticator that tells a bridge authority to
serve all requested bridge information. Used by the (only partially
diff --git a/src/feature/dirauth/dirauth_config.c b/src/feature/dirauth/dirauth_config.c
index 53c9f9f781..f98513ef75 100644
--- a/src/feature/dirauth/dirauth_config.c
+++ b/src/feature/dirauth/dirauth_config.c
@@ -434,6 +434,11 @@ dirauth_options_validate(const void *arg, char **msg)
"Recommended*Versions.");
}
+ if (options->AuthDirVoteGuardBwThresholdFraction > 1.0 ||
+ options->AuthDirVoteGuardBwThresholdFraction < 0.0) {
+ REJECT("Guard bandwdith threshold fraction is invalid.");
+ }
+
char *t;
/* Call these functions to produce warnings only. */
t = format_recommended_version_list(options->RecommendedClientVersions, 1);
diff --git a/src/feature/dirauth/dirauth_options.inc b/src/feature/dirauth/dirauth_options.inc
index 4fd07a8859..7ee0201e1a 100644
--- a/src/feature/dirauth/dirauth_options.inc
+++ b/src/feature/dirauth/dirauth_options.inc
@@ -76,6 +76,31 @@ CONF_VAR(RecommendedClientVersions, LINELIST, 0, NULL)
/** Which versions of tor should we tell users to run on relays? */
CONF_VAR(RecommendedServerVersions, LINELIST, 0, NULL)
+/** Relays which should be voted Guard regardless of uptime and bandwidth. */
+CONF_VAR(AuthDirVoteGuard, ROUTERSET, 0, NULL)
+
+/** If a relay's uptime is at least this value, then it is always considered
+ * stable, regardless of the rest of the network. This way we resist attacks
+ * where an attacker doubles the size of the network using allegedly
+ * high-uptime nodes, displacing all the current guards. */
+CONF_VAR(AuthDirVoteStableGuaranteeMinUptime, INTERVAL, 0, "30 days")
+
+/** If a relay's MTBF is at least this value, then it is always stable. See
+ * above. */
+CONF_VAR(AuthDirVoteStableGuaranteeMTBF, INTERVAL, 0, "5 days")
+
+/** A relay with at least this much weighted time known can be considered
+ * familiar enough to be a guard. */
+CONF_VAR(AuthDirVoteGuardGuaranteeTimeKnown, INTERVAL, 0, "8 days")
+
+/** A relay with sufficient WFU is around enough to be a guard. */
+CONF_VAR(AuthDirVoteGuardGuaranteeWFU, DOUBLE, 0, "0.98")
+
+/** The Guard flag bandwidth performance threshold fraction that is the
+ * fraction representing who gets the Guard flag out of all measured
+ * bandwidth. */
+CONF_VAR(AuthDirVoteGuardBwThresholdFraction, DOUBLE, 0, "0.75")
+
/** If an authority has been around for less than this amount of time, it
* does not believe its reachability information is accurate. Only
* altered on testing networks. */
diff --git a/src/feature/dirauth/voteflags.c b/src/feature/dirauth/voteflags.c
index 9aefc6c5b4..71ee03e265 100644
--- a/src/feature/dirauth/voteflags.c
+++ b/src/feature/dirauth/voteflags.c
@@ -36,24 +36,6 @@
#include "lib/container/order.h"
-/** If a router's uptime is at least this value, then it is always
- * considered stable, regardless of the rest of the network. This
- * way we resist attacks where an attacker doubles the size of the
- * network using allegedly high-uptime nodes, displacing all the
- * current guards. */
-#define UPTIME_TO_GUARANTEE_STABLE (3600*24*30)
-/** If a router's MTBF is at least this value, then it is always stable.
- * See above. (Corresponds to about 7 days for current decay rates.) */
-#define MTBF_TO_GUARANTEE_STABLE (60*60*24*5)
-/** Similarly, every node with at least this much weighted time known can be
- * considered familiar enough to be a guard. Corresponds to about 20 days for
- * current decay rates.
- */
-#define TIME_KNOWN_TO_GUARANTEE_FAMILIAR (8*24*60*60)
-/** Similarly, every node with sufficient WFU is around enough to be a guard.
- */
-#define WFU_TO_GUARANTEE_GUARD (0.98)
-
/* Thresholds for server performance: set by
* dirserv_compute_performance_thresholds, and used by
* generate_v2_networkstatus */
@@ -111,13 +93,13 @@ dirserv_thinks_router_is_unreliable(time_t now,
*/
long uptime = real_uptime(router, now);
if ((unsigned)uptime < stable_uptime &&
- (unsigned)uptime < UPTIME_TO_GUARANTEE_STABLE)
+ uptime < dirauth_get_options()->AuthDirVoteStableGuaranteeMinUptime)
return 1;
} else {
double mtbf =
rep_hist_get_stability(router->cache_info.identity_digest, now);
if (mtbf < stable_mtbf &&
- mtbf < MTBF_TO_GUARANTEE_STABLE)
+ mtbf < dirauth_get_options()->AuthDirVoteStableGuaranteeMTBF)
return 1;
}
}
@@ -325,13 +307,15 @@ dirserv_compute_performance_thresholds(digestmap_t *omit_as_sybil)
/* (Now bandwidths is sorted.) */
if (fast_bandwidth_kb < RELAY_REQUIRED_MIN_BANDWIDTH/(2 * 1000))
fast_bandwidth_kb = bandwidths_kb[n_active/4];
+ int nth = (int)(n_active *
+ dirauth_options->AuthDirVoteGuardBwThresholdFraction);
guard_bandwidth_including_exits_kb =
- third_quartile_uint32(bandwidths_kb, n_active);
+ find_nth_uint32(bandwidths_kb, n_active, nth);
guard_tk = find_nth_long(tks, n_active, n_active/8);
}
- if (guard_tk > TIME_KNOWN_TO_GUARANTEE_FAMILIAR)
- guard_tk = TIME_KNOWN_TO_GUARANTEE_FAMILIAR;
+ if (guard_tk > dirauth_options->AuthDirVoteGuardGuaranteeTimeKnown)
+ guard_tk = dirauth_options->AuthDirVoteGuardGuaranteeTimeKnown;
{
/* We can vote on a parameter for the minimum and maximum. */
@@ -379,15 +363,16 @@ dirserv_compute_performance_thresholds(digestmap_t *omit_as_sybil)
} SMARTLIST_FOREACH_END(node);
if (n_familiar)
guard_wfu = median_double(wfus, n_familiar);
- if (guard_wfu > WFU_TO_GUARANTEE_GUARD)
- guard_wfu = WFU_TO_GUARANTEE_GUARD;
+ if (guard_wfu > dirauth_options->AuthDirVoteGuardGuaranteeWFU)
+ guard_wfu = dirauth_options->AuthDirVoteGuardGuaranteeWFU;
enough_mtbf_info = rep_hist_have_measured_enough_stability();
if (n_active_nonexit) {
+ int nth = (int)(n_active_nonexit *
+ dirauth_options->AuthDirVoteGuardBwThresholdFraction);
guard_bandwidth_excluding_exits_kb =
- find_nth_uint32(bandwidths_excluding_exits_kb,
- n_active_nonexit, n_active_nonexit*3/4);
+ find_nth_uint32(bandwidths_excluding_exits_kb, n_active_nonexit, nth);
}
log_info(LD_DIRSERV,
@@ -573,6 +558,21 @@ should_publish_node_ipv6(const node_t *node, const routerinfo_t *ri,
router_is_me(ri));
}
+/** Set routerstatus flags based on the authority options. Same as the testing
+ * function but for the main network. */
+static void
+dirserv_set_routerstatus_flags(routerstatus_t *rs)
+{
+ const dirauth_options_t *options = dirauth_get_options();
+
+ tor_assert(rs);
+
+ /* Assign Guard flag to relays that can get it unconditionnaly. */
+ if (routerset_contains_routerstatus(options->AuthDirVoteGuard, rs, 0)) {
+ rs->is_possible_guard = 1;
+ }
+}
+
/**
* Extract status information from <b>ri</b> and from other authority
* functions and store it in <b>rs</b>, as per
@@ -638,6 +638,8 @@ dirauth_set_routerstatus_from_routerinfo(routerstatus_t *rs,
if (options->TestingTorNetwork) {
dirserv_set_routerstatus_testing(rs);
+ } else {
+ dirserv_set_routerstatus_flags(rs);
}
}
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