Merge branch 'ahf_bugs_21641_squashed'

changes/bug21641

@@ -0,0 +1,5 @@
+  o Minor feature (defaults, directory):
+    - Onion key rotation and expiry intervals are now defined as a network
+      consensus parameter as per proposal #274. The default lifetime of an
+      onion key is bumped from 7 to 28 days. Old onion keys will expire after 7
+      days by default. Fixes bug #21641.

src/or/config.c

@@ -2815,7 +2815,7 @@ compute_publishserverdescriptor(or_options_t *options)
 #define MAX_PREDICTED_CIRCS_RELEVANCE (60*60)
 
 /** Highest allowable value for RendPostPeriod. */
-#define MAX_DIR_PERIOD (MIN_ONION_KEY_LIFETIME/2)
+#define MAX_DIR_PERIOD ((7*24*60*60)/2)
 
 /** Lowest allowable value for MaxCircuitDirtiness; if this is too low, Tor
  * will generate too many circuits and potentially overload the network. */

src/or/main.c

@@ -1161,6 +1161,7 @@ static int periodic_events_initialized = 0;
 #define CALLBACK(name) \
   static int name ## _callback(time_t, const or_options_t *)
 CALLBACK(rotate_onion_key);
+CALLBACK(check_onion_keys_expiry_time);
 CALLBACK(check_ed_keys);
 CALLBACK(launch_descriptor_fetches);
 CALLBACK(rotate_x509_certificate);
@@ -1192,6 +1193,7 @@ CALLBACK(heartbeat);
 
 static periodic_event_item_t periodic_events[] = {
   CALLBACK(rotate_onion_key),
+  CALLBACK(check_onion_keys_expiry_time),
   CALLBACK(check_ed_keys),
   CALLBACK(launch_descriptor_fetches),
   CALLBACK(rotate_x509_certificate),
@@ -1472,17 +1474,18 @@ run_scheduled_events(time_t now)
     pt_configure_remaining_proxies();
 }
 
-/* Periodic callback: Every MIN_ONION_KEY_LIFETIME seconds, rotate the onion
- * keys, shut down and restart all cpuworkers, and update our descriptor if
- * necessary.
+/* Periodic callback: rotate the onion keys after the period defined by the
+ * "onion-key-rotation-days" consensus parameter, shut down and restart all
+ * cpuworkers, and update our descriptor if necessary.
  */
 static int
 rotate_onion_key_callback(time_t now, const or_options_t *options)
 {
   if (server_mode(options)) {
-    time_t rotation_time = get_onion_key_set_at()+MIN_ONION_KEY_LIFETIME;
+    int onion_key_lifetime = get_onion_key_lifetime();
+    time_t rotation_time = get_onion_key_set_at()+onion_key_lifetime;
     if (rotation_time > now) {
-      return safe_timer_diff(now, rotation_time);
+      return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
     }
 
     log_info(LD_GENERAL,"Rotating onion key.");
@@ -1493,11 +1496,35 @@ rotate_onion_key_callback(time_t now, const or_options_t *options)
     }
     if (advertised_server_mode() && !options->DisableNetwork)
       router_upload_dir_desc_to_dirservers(0);
-    return MIN_ONION_KEY_LIFETIME;
+    return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
   }
   return PERIODIC_EVENT_NO_UPDATE;
 }
 
+/* Period callback: Check if our old onion keys are still valid after the
+ * period of time defined by the consensus parameter
+ * "onion-key-grace-period-days", otherwise expire them by setting them to
+ * NULL.
+ */
+static int
+check_onion_keys_expiry_time_callback(time_t now, const or_options_t *options)
+{
+  if (server_mode(options)) {
+    int onion_key_grace_period = get_onion_key_grace_period();
+    time_t expiry_time = get_onion_key_set_at()+onion_key_grace_period;
+    if (expiry_time > now) {
+      return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
+    }
+
+    log_info(LD_GENERAL, "Expiring old onion keys.");
+    expire_old_onion_keys();
+    cpuworkers_rotate_keyinfo();
+    return ONION_KEY_CONSENSUS_CHECK_INTERVAL;
+  }
+
+  return PERIODIC_EVENT_NO_UPDATE;
+}
+
 /* Periodic callback: Every 30 seconds, check whether it's time to make new
  * Ed25519 subkeys.
  */

src/or/or.h

@@ -147,8 +147,27 @@
 /** Maximum size of a single extrainfo document, as above. */
 #define MAX_EXTRAINFO_UPLOAD_SIZE 50000
 
-/** How often do we rotate onion keys? */
-#define MIN_ONION_KEY_LIFETIME (7*24*60*60)
+/** Minimum lifetime for an onion key in days. */
+#define MIN_ONION_KEY_LIFETIME_DAYS (1)
+
+/** Maximum lifetime for an onion key in days. */
+#define MAX_ONION_KEY_LIFETIME_DAYS (90)
+
+/** Default lifetime for an onion key in days. */
+#define DEFAULT_ONION_KEY_LIFETIME_DAYS (28)
+
+/** Minimum grace period for acceptance of an onion key in days.
+ * The maximum value is defined in proposal #274 as being the current network
+ * consensus parameter for "onion-key-rotation-days". */
+#define MIN_ONION_KEY_GRACE_PERIOD_DAYS (1)
+
+/** Default grace period for acceptance of an onion key in days. */
+#define DEFAULT_ONION_KEY_GRACE_PERIOD_DAYS (7)
+
+/** How often we should check the network consensus if it is time to rotate or
+ * expire onion keys. */
+#define ONION_KEY_CONSENSUS_CHECK_INTERVAL (60*60)
+
 /** How often do we rotate TLS contexts? */
 #define MAX_SSL_KEY_LIFETIME_INTERNAL (2*60*60)
 

src/or/router.c

@@ -148,6 +148,51 @@ dup_onion_keys(crypto_pk_t **key, crypto_pk_t **last)
   tor_mutex_release(key_lock);
 }
 
+/** Expire our old set of onion keys. This is done by setting
+ * last_curve25519_onion_key and lastonionkey to all zero's and NULL
+ * respectively.
+ *
+ * This function does not perform any grace period checks for the old onion
+ * keys.
+ */
+void
+expire_old_onion_keys(void)
+{
+  char *fname = NULL;
+
+  tor_mutex_acquire(key_lock);
+
+  /* Free lastonionkey and set it to NULL. */
+  if (lastonionkey) {
+    crypto_pk_free(lastonionkey);
+    lastonionkey = NULL;
+  }
+
+  /* We zero out the keypair. See the tor_mem_is_zero() check made in
+   * construct_ntor_key_map() below. */
+  memset(&last_curve25519_onion_key, 0, sizeof(last_curve25519_onion_key));
+
+  tor_mutex_release(key_lock);
+
+  fname = get_datadir_fname2("keys", "secret_onion_key.old");
+  if (file_status(fname) == FN_FILE) {
+    if (tor_unlink(fname) != 0) {
+      log_warn(LD_FS, "Couldn't unlink old onion key file %s: %s",
+               fname, strerror(errno));
+    }
+  }
+  tor_free(fname);
+
+  fname = get_datadir_fname2("keys", "secret_onion_key_ntor.old");
+  if (file_status(fname) == FN_FILE) {
+    if (tor_unlink(fname) != 0) {
+      log_warn(LD_FS, "Couldn't unlink old ntor onion key file %s: %s",
+               fname, strerror(errno));
+    }
+  }
+  tor_free(fname);
+}
+
 /** Return the current secret onion key for the ntor handshake. Must only
  * be called from the main thread. */
 static const curve25519_keypair_t *
@@ -683,6 +728,47 @@ v3_authority_check_key_expiry(void)
   last_warned = now;
 }
 
+/** Get the lifetime of an onion key in days. This value is defined by the
+ * network consesus parameter "onion-key-rotation-days". Always returns a value
+ * between <b>MIN_ONION_KEY_LIFETIME_DAYS</b> and
+ * <b>MAX_ONION_KEY_LIFETIME_DAYS</b>.
+ */
+static int
+get_onion_key_rotation_days_(void)
+{
+  return networkstatus_get_param(NULL,
+                                 "onion-key-rotation-days",
+                                 DEFAULT_ONION_KEY_LIFETIME_DAYS,
+                                 MIN_ONION_KEY_LIFETIME_DAYS,
+                                 MAX_ONION_KEY_LIFETIME_DAYS);
+}
+
+/** Get the current lifetime of an onion key in seconds. This value is defined
+ * by the network consesus parameter "onion-key-rotation-days", but the value
+ * is converted to seconds.
+ */
+int
+get_onion_key_lifetime(void)
+{
+  return get_onion_key_rotation_days_()*24*60*60;
+}
+
+/** Get the grace period of an onion key in seconds. This value is defined by
+ * the network consesus parameter "onion-key-grace-period-days", but the value
+ * is converted to seconds.
+ */
+int
+get_onion_key_grace_period(void)
+{
+  int grace_period;
+  grace_period = networkstatus_get_param(NULL,
+                                         "onion-key-grace-period-days",
+                                         DEFAULT_ONION_KEY_GRACE_PERIOD_DAYS,
+                                         MIN_ONION_KEY_GRACE_PERIOD_DAYS,
+                                         get_onion_key_rotation_days_());
+  return grace_period*24*60*60;
+}
+
 /** Set up Tor's TLS contexts, based on our configuration and keys. Return 0
  * on success, and -1 on failure. */
 int
@@ -928,7 +1014,7 @@ init_keys(void)
       /* We have no LastRotatedOnionKey set; either we just created the key
        * or it's a holdover from 0.1.2.4-alpha-dev or earlier.  In either case,
        * start the clock ticking now so that we will eventually rotate it even
-       * if we don't stay up for a full MIN_ONION_KEY_LIFETIME. */
+       * if we don't stay up for the full lifetime of an onion key. */
       state->LastRotatedOnionKey = onionkey_set_at = now;
       or_state_mark_dirty(state, options->AvoidDiskWrites ?
                                    time(NULL)+3600 : 0);
@@ -2760,7 +2846,7 @@ router_dump_router_to_string(routerinfo_t *router,
       make_ntor_onion_key_crosscert(ntor_keypair,
                          &router->cache_info.signing_key_cert->signing_key,
                          router->cache_info.published_on,
-                         MIN_ONION_KEY_LIFETIME, &sign);
+                         get_onion_key_lifetime(), &sign);
     if (!cert) {
       log_warn(LD_BUG,"make_ntor_onion_key_crosscert failed!");
       goto err;

src/or/router.h

@@ -27,10 +27,13 @@ crypto_pk_t *get_my_v3_authority_signing_key(void);
 authority_cert_t *get_my_v3_legacy_cert(void);
 crypto_pk_t *get_my_v3_legacy_signing_key(void);
 void dup_onion_keys(crypto_pk_t **key, crypto_pk_t **last);
+void expire_old_onion_keys(void);
 void rotate_onion_key(void);
 crypto_pk_t *init_key_from_file(const char *fname, int generate,
                                     int severity, int log_greeting);
 void v3_authority_check_key_expiry(void);
+int get_onion_key_lifetime(void);
+int get_onion_key_grace_period(void);
 
 di_digest256_map_t *construct_ntor_key_map(void);
 void ntor_key_map_free(di_digest256_map_t *map);

src/test/test_dir.c

@@ -329,7 +329,7 @@ test_dir_formats(void *arg)
     ntor_cc = make_ntor_onion_key_crosscert(&r2_onion_keypair,
                                           &kp1.pubkey,
                                           r2->cache_info.published_on,
-                                          MIN_ONION_KEY_LIFETIME,
+                                          get_onion_key_lifetime(),
                                           &ntor_cc_sign);
     tt_assert(ntor_cc);
     base64_encode(cert_buf, sizeof(cert_buf),