Ticket #17857: Apply padding off-switch to existing connections.

src/or/channel.c

@@ -66,6 +66,7 @@
 #include "scheduler.h"
 #include "compat_time.h"
 #include "networkstatus.h"
+#include "rendservice.h"
 
 /* Global lists of channels */
 
@@ -2712,17 +2713,26 @@ channel_do_open_actions(channel_t *chan)
 
   /* Disable or reduce padding according to user prefs. */
   if (chan->padding_enabled || get_options()->ConnectionPadding == 1) {
-    if (!get_options()->ConnectionPadding ||
-        (get_options()->Tor2webMode &&
-         !networkstatus_get_param(NULL, "nf_pad_tor2web", 1, 0, 1))
-        || (get_options()->HiddenServiceSingleHopMode &&
-            !networkstatus_get_param(NULL, "nf_pad_single_onion", 1, 0, 1))) {
+    if (!get_options()->ConnectionPadding) {
+      /* Disable if torrc disabled */
       channelpadding_disable_padding_on_channel(chan);
-    }
-
-    /* Padding can be forced and/or reduced by clients, regardless of if
-     * the channel supports it */
-    if (get_options()->ReducedConnectionPadding) {
+    } else if (get_options()->Tor2webMode &&
+            !networkstatus_get_param(NULL,
+                                     CHANNELPADDING_TOR2WEB_PARAM,
+                                     CHANNELPADDING_TOR2WEB_DEFAULT, 0, 1)) {
+      /* Disable if we're using tor2web and the consensus disabled padding
+       * for tor2web */
+      channelpadding_disable_padding_on_channel(chan);
+    } else if (rend_service_allow_non_anonymous_connection(get_options()) &&
+               !networkstatus_get_param(NULL,
+                                        CHANNELPADDING_SOS_PARAM,
+                                        CHANNELPADDING_SOS_DEFAULT, 0, 1)) {
+      /* Disable if we're using RSOS and the consensus disabled padding
+       * for RSOS*/
+      channelpadding_disable_padding_on_channel(chan);
+    } else if (get_options()->ReducedConnectionPadding) {
+      /* Padding can be forced and/or reduced by clients, regardless of if
+       * the channel supports it */
       channelpadding_reduce_padding_on_channel(chan);
     }
   }

src/or/channelpadding.c

@@ -21,6 +21,7 @@
 #include "router.h"
 #include "compat_time.h"
 #include <event2/event.h>
+#include "rendservice.h"
 
 STATIC int channelpadding_get_netflow_inactive_timeout_ms(const channel_t *);
 STATIC int channelpadding_send_disable_command(channel_t *);
@@ -136,10 +137,14 @@ channelpadding_new_consensus_params(networkstatus_t *ns)
     networkstatus_get_param(ns, "nf_pad_relays", 0, 0, 1);
 
   consensus_nf_pad_tor2web =
-    networkstatus_get_param(ns, "nf_pad_tor2web", 1, 0, 1);
+    networkstatus_get_param(ns,
+                            CHANNELPADDING_TOR2WEB_PARAM,
+                            CHANNELPADDING_TOR2WEB_DEFAULT, 0, 1);
 
   consensus_nf_pad_single_onion =
-    networkstatus_get_param(ns, "nf_pad_single_onion", 1, 0, 1);
+    networkstatus_get_param(ns,
+                            CHANNELPADDING_SOS_PARAM,
+                            CHANNELPADDING_SOS_DEFAULT, 0, 1);
 }
 
 /**
@@ -717,11 +722,24 @@ channelpadding_decide_to_pad_channel(channel_t *chan)
     return CHANNELPADDING_WONTPAD;
   }
 
-  if (options->Tor2webMode && !consensus_nf_pad_tor2web)
+  if (options->Tor2webMode && !consensus_nf_pad_tor2web) {
+    /* If the consensus just changed values, this channel may still
+     * think padding is enabled. Negotiate it off. */
+    if (chan->padding_enabled)
+      channelpadding_disable_padding_on_channel(chan);
+
     return CHANNELPADDING_WONTPAD;
+  }
+
+  if (rend_service_allow_non_anonymous_connection(options) &&
+      !consensus_nf_pad_single_onion) {
+    /* If the consensus just changed values, this channel may still
+     * think padding is enabled. Negotiate it off. */
+    if (chan->padding_enabled)
+      channelpadding_disable_padding_on_channel(chan);
 
-  if (options->HiddenServiceSingleHopMode && !consensus_nf_pad_single_onion)
     return CHANNELPADDING_WONTPAD;
+  }
 
   if (!chan->has_queued_writes(chan)) {
     int is_client_channel = 0;

src/or/channelpadding.h

@@ -13,6 +13,11 @@
 
 #include "channelpadding_negotiation.h"
 
+#define CHANNELPADDING_TOR2WEB_PARAM  "nf_pad_tor2web"
+#define CHANNELPADDING_TOR2WEB_DEFAULT 1
+#define CHANNELPADDING_SOS_PARAM  "nf_pad_single_onion"
+#define CHANNELPADDING_SOS_DEFAULT 1
+
 typedef enum {
   CHANNELPADDING_WONTPAD,
   CHANNELPADDING_PADLATER,

src/test/test_channelpadding.c

@@ -371,6 +371,7 @@ test_channelpadding_killonehop(void *arg)
   timers_initialize();
 
   setup_mock_consensus();
+  setup_mock_network();
 
   /* Do we disable padding if tor2webmode or rsos are enabled, and
    * the consensus says don't pad?  */
@@ -380,7 +381,6 @@ test_channelpadding_killonehop(void *arg)
   smartlist_clear(current_md_consensus->net_params);
   channelpadding_new_consensus_params(current_md_consensus);
 
-  setup_mock_network();
   tried_to_write_cell = 0;
   get_options_mutable()->Tor2webMode = 1;
   client_relay3->next_padding_time_ms = monotime_coarse_absolute_msec() + 100;
@@ -402,17 +402,35 @@ test_channelpadding_killonehop(void *arg)
                 (void*)"nf_pad_tor2web=0");
   channelpadding_new_consensus_params(current_md_consensus);
 
-  // Test client side (it should stop immediately)
+  // Before the client tries to pad, the relay will still pad:
+  tried_to_write_cell = 0;
+  relay3_client->next_padding_time_ms = monotime_coarse_absolute_msec() + 100;
+  get_options_mutable()->ORPort_set = 1;
+  get_options_mutable()->Tor2webMode = 0;
+  decision = channelpadding_decide_to_pad_channel(relay3_client);
+  tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED);
+  tt_assert(relay3_client->pending_padding_callback);
+
+  // Wait for the timer
+  event_base_loop(tor_libevent_get_base(), 0);
+  tt_int_op(tried_to_write_cell, OP_EQ, 1);
+  tt_assert(!client_relay3->pending_padding_callback);
+
+  // Test client side (it should stop immediately, but send a negotiate)
+  tried_to_write_cell = 0;
+  tt_assert(relay3_client->padding_enabled);
+  tt_assert(client_relay3->padding_enabled);
+  get_options_mutable()->Tor2webMode = 1;
+  /* For the relay to recieve the negotiate: */
+  get_options_mutable()->ORPort_set = 1;
   decision = channelpadding_decide_to_pad_channel(client_relay3);
   tt_int_op(decision, OP_EQ, CHANNELPADDING_WONTPAD);
+  tt_int_op(tried_to_write_cell, OP_EQ, 1);
   tt_assert(!client_relay3->pending_padding_callback);
-
-  // Reset connnections.. XXX: remove this requirement via client
-  // negotiation
-  free_mock_network();
-  setup_mock_network();
+  tt_assert(!relay3_client->padding_enabled);
 
   // Test relay side (it should have gotten the negotiation to disable)
+  get_options_mutable()->ORPort_set = 1;
   get_options_mutable()->Tor2webMode = 0;
   tt_int_op(channelpadding_decide_to_pad_channel(relay3_client), OP_EQ,
       CHANNELPADDING_WONTPAD);
@@ -423,11 +441,13 @@ test_channelpadding_killonehop(void *arg)
   smartlist_clear(current_md_consensus->net_params);
   channelpadding_new_consensus_params(current_md_consensus);
 
-  // Reset connections
-  free_mock_network();
-  setup_mock_network();
+  relay3_client->padding_enabled = 1;
+  client_relay3->padding_enabled = 1;
+
   tried_to_write_cell = 0;
+  get_options_mutable()->ORPort_set = 0;
   get_options_mutable()->HiddenServiceSingleHopMode = 1;
+  get_options_mutable()->HiddenServiceNonAnonymousMode = 1;
   client_relay3->next_padding_time_ms = monotime_coarse_absolute_msec() + 100;
   decision = channelpadding_decide_to_pad_channel(client_relay3);
   tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED);
@@ -447,17 +467,34 @@ test_channelpadding_killonehop(void *arg)
                 (void*)"nf_pad_single_onion=0");
   channelpadding_new_consensus_params(current_md_consensus);
 
+  // Before the client tries to pad, the relay will still pad:
+  tried_to_write_cell = 0;
+  relay3_client->next_padding_time_ms = monotime_coarse_absolute_msec() + 100;
+  get_options_mutable()->ORPort_set = 1;
+  get_options_mutable()->HiddenServiceSingleHopMode = 0;
+  get_options_mutable()->HiddenServiceNonAnonymousMode = 0;
+  decision = channelpadding_decide_to_pad_channel(relay3_client);
+  tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED);
+  tt_assert(relay3_client->pending_padding_callback);
+
+  // Wait for the timer
+  event_base_loop(tor_libevent_get_base(), 0);
+  tt_int_op(tried_to_write_cell, OP_EQ, 1);
+  tt_assert(!client_relay3->pending_padding_callback);
+
   // Test client side (it should stop immediately)
+  get_options_mutable()->HiddenServiceSingleHopMode = 1;
+  get_options_mutable()->HiddenServiceNonAnonymousMode = 1;
+  /* For the relay to recieve the negotiate: */
+  get_options_mutable()->ORPort_set = 1;
   decision = channelpadding_decide_to_pad_channel(client_relay3);
   tt_int_op(decision, OP_EQ, CHANNELPADDING_WONTPAD);
   tt_assert(!client_relay3->pending_padding_callback);
 
-  // Reset connnections.. XXX: remove this requirement...
-  free_mock_network();
-  setup_mock_network();
-
   // Test relay side (it should have gotten the negotiation to disable)
+  get_options_mutable()->ORPort_set = 1;
   get_options_mutable()->HiddenServiceSingleHopMode = 0;
+  get_options_mutable()->HiddenServiceNonAnonymousMode = 0;
   tt_int_op(channelpadding_decide_to_pad_channel(relay3_client), OP_EQ,
       CHANNELPADDING_WONTPAD);
   tt_assert(!relay3_client->padding_enabled);