[tor-commits] [tor/master] Add a new isolation type and field: "nym epoch"

[nickm at torproject.org]

commit 1d3c8c1f74e9f80317a70c3b7d9372dee87dd373
Author: Nick Mathewson <nickm at torproject.org>
Date:   Wed Jul 6 16:39:54 2011 -0400

    Add a new isolation type and field: "nym epoch"
    
    The "nym epoch" of a stream is defined as the number of times that
    NEWNYM had been called before the stream was opened.  All streams
    are isolated by nym epoch.
    
    This feature should be redundant with existing signewnym stuff, but
    it provides a good belt-and-suspenders way for us to avoid ever
    letting any circuit type bypass signewnym.
---
 src/or/connection.c      |    1 +
 src/or/connection_edge.c |    7 +++++++
 src/or/dnsserv.c         |    1 +
 src/or/main.c            |   11 +++++++++++
 src/or/main.h            |    1 +
 src/or/or.h              |    7 ++++++-
 6 files changed, 27 insertions(+), 1 deletions(-)

diff --git a/src/or/connection.c b/src/or/connection.c
index b627dca..09b45e0 100644
--- a/src/or/connection.c
+++ b/src/or/connection.c
@@ -1240,6 +1240,7 @@ connection_init_accepted_conn(connection_t *conn,
     case CONN_TYPE_AP:
       TO_EDGE_CONN(conn)->isolation_flags = listener->isolation_flags;
       TO_EDGE_CONN(conn)->session_group = listener->session_group;
+      TO_EDGE_CONN(conn)->nym_epoch = get_signewnym_epoch();
       switch (TO_CONN(listener)->type) {
         case CONN_TYPE_AP_LISTENER:
           conn->state = AP_CONN_STATE_SOCKS_WAIT;
diff --git a/src/or/connection_edge.c b/src/or/connection_edge.c
index 426c342..ce555ed 100644
--- a/src/or/connection_edge.c
+++ b/src/or/connection_edge.c
@@ -3296,6 +3296,8 @@ connection_edge_streams_are_compatible(const edge_connection_t *a,
     return 0;
   if ((iso & ISO_SESSIONGRP) && a->session_group != b->session_group)
     return 0;
+  if ((iso & ISO_NYM_EPOCH) && a->nym_epoch != b->nym_epoch)
+    return 0;
 
   return 1;
 }
@@ -3348,6 +3350,8 @@ connection_edge_compatible_with_circuit(const edge_connection_t *conn,
     return 0;
   if ((iso & ISO_SESSIONGRP) && conn->session_group != circ->session_group)
     return 0;
+  if ((iso & ISO_NYM_EPOCH) && conn->nym_epoch != circ->nym_epoch)
+    return 0;
 
   return 1;
 }
@@ -3374,6 +3378,7 @@ connection_edge_update_circuit_isolation(const edge_connection_t *conn,
     circ->client_proto_socksver = conn->socks_request->socks_version;
     tor_addr_copy(&circ->client_addr, &TO_CONN(conn)->addr);
     circ->session_group = conn->session_group;
+    circ->nym_epoch = conn->nym_epoch;
     /* XXXX023 auth too, once #1666 is in. */
 
     circ->isolation_values_set = 1;
@@ -3394,6 +3399,8 @@ connection_edge_update_circuit_isolation(const edge_connection_t *conn,
       mixed |= ISO_CLIENTADDR;
     if (conn->session_group != circ->session_group)
       mixed |= ISO_SESSIONGRP;
+    if (conn->nym_epoch != circ->nym_epoch)
+      mixed |= ISO_NYM_EPOCH;
 
     if (dry_run)
       return mixed;
diff --git a/src/or/dnsserv.c b/src/or/dnsserv.c
index b1316ec..8612b48 100644
--- a/src/or/dnsserv.c
+++ b/src/or/dnsserv.c
@@ -134,6 +134,7 @@ evdns_server_callback(struct evdns_server_request *req, void *data_)
   conn->dns_server_request = req;
   conn->isolation_flags = listener->isolation_flags;
   conn->session_group = listener->session_group;
+  conn->nym_epoch = get_signewnym_epoch();
 
   if (connection_add(TO_CONN(conn)) < 0) {
     log_warn(LD_APP, "Couldn't register dummy connection for DNS request");
diff --git a/src/or/main.c b/src/or/main.c
index 16d4f0e..54e6451 100644
--- a/src/or/main.c
+++ b/src/or/main.c
@@ -114,6 +114,8 @@ static time_t time_to_check_for_correct_dns = 0;
 static time_t time_of_last_signewnym = 0;
 /** Is there a signewnym request we're currently waiting to handle? */
 static int signewnym_is_pending = 0;
+/** How many times have we called newnym? */
+static unsigned newnym_epoch = 0;
 
 /** Smartlist of all open connections. */
 static smartlist_t *connection_array = NULL;
@@ -1038,9 +1040,18 @@ signewnym_impl(time_t now)
   time_of_last_signewnym = now;
   signewnym_is_pending = 0;
 
+  ++newnym_epoch;
+
   control_event_signal(SIGNEWNYM);
 }
 
+/** Return the number of times that signewnym has been called. */
+unsigned
+get_signewnym_epoch(void)
+{
+  return newnym_epoch;
+}
+
 /** Perform regular maintenance tasks.  This function gets run once per
  * second by second_elapsed_callback().
  */
diff --git a/src/or/main.h b/src/or/main.h
index db25135..c890364 100644
--- a/src/or/main.h
+++ b/src/or/main.h
@@ -52,6 +52,7 @@ void ip_address_changed(int at_interface);
 void dns_servers_relaunch_checks(void);
 
 long get_uptime(void);
+unsigned get_signewnym_epoch(void);
 
 void handle_signals(int is_parent);
 void process_signal(uintptr_t sig);
diff --git a/src/or/or.h b/src/or/or.h
index c5e5793..9cf508c 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -1212,6 +1212,8 @@ typedef struct edge_connection_t {
   uint8_t isolation_flags;
   /** AP only: what session group is this stream in? */
   int session_group;
+  /** AP only: The newnym epoch in which we created this connection. */
+  unsigned nym_epoch;
   /* Other fields to isolate on already exist.  The ClientAddr is addr.  The
      ClientProtocol is a combination of type and socks_request->
      socks_version.  SocksAuth will be added to socks_request by ticket
@@ -2482,6 +2484,7 @@ typedef struct origin_circuit_t {
   tor_addr_t client_addr;
   char *dest_address;
   int session_group;
+  unsigned nym_epoch;
   /* XXXX023 do auth once #1666 is merged */
   /**@}*/
 
@@ -2621,10 +2624,12 @@ typedef enum invalid_router_usage_t {
 #define ISO_CLIENTADDR  (1u<<4)
 /** Isolate based on session group (always on). */
 #define ISO_SESSIONGRP  (1u<<5)
+/** Isolate based on newnym epoch (always on). */
+#define ISO_NYM_EPOCH   (1u<<6)
 /**@}*/
 
 /** Default isolation level for ports. */
-#define ISO_DEFAULT (ISO_CLIENTADDR|ISO_SOCKSAUTH|ISO_SESSIONGRP)
+#define ISO_DEFAULT (ISO_CLIENTADDR|ISO_SOCKSAUTH|ISO_SESSIONGRP|ISO_NYM_EPOCH)
 
 /** Configuration for a single port that we're listening on. */
 typedef struct port_cfg_t {