Merge branch 'maint-0.2.2' into release-0.2.2

16 files changed, 193 insertions, 60 deletions

diff --git a/changes/bug2317 b/changes/bug2317
new file mode 100644
index 0000000000..0b9366c36f
--- /dev/null
+++ b/changes/bug2317
@@ -0,0 +1,9 @@
+  o Major features:
+    - Introduce minimum/maximum values that a client is going to believe
+      in a consensus. This helps to avoid crashes or worse when a param
+      has a weird value.
+
+  o Major bugfixes:
+    - Prevent crash/heap corruption when cbtnumnodes consensus parameter is
+      set to 0 or large values. Fixes bug 2317.
+
diff --git a/doc/spec/dir-spec.txt b/doc/spec/dir-spec.txt
index 6e35deb00e..eebceeafd6 100644
--- a/doc/spec/dir-spec.txt
+++ b/doc/spec/dir-spec.txt
@@ -1161,12 +1161,14 @@
         research indicates that a lower value would mean fewer cells in
         transit in the network at any given time. Obeyed by Tor 0.2.1.20
         and later.
+        Min: 100, Max: 1000
 
         "CircuitPriorityHalflifeMsec" -- the halflife parameter used when
         weighting which circuit will send the next cell. Obeyed by Tor
         0.2.2.10-alpha and later.  (Versions of Tor between 0.2.2.7-alpha
         and 0.2.2.10-alpha recognized a "CircPriorityHalflifeMsec" parameter,
         but mishandled it badly.)
+        Min: -1, Max: 2147483647 (INT32_MAX)
 
         "perconnbwrate" and "perconnbwburst" -- if set, each relay sets
         up a separate token bucket for every client OR connection,
@@ -1176,12 +1178,14 @@
         and later. (Note that relays running 0.2.2.7-alpha through
         0.2.2.14-alpha looked for bwconnrate and bwconnburst, but then
         did the wrong thing with them; see bug 1830 for details.)
+        Min: 1, Max: 2147483647 (INT32_MAX)
 
-        "refuseunknownexits" -- if set and non-zero, exit relays look at
+        "refuseunknownexits" -- if set to one, exit relays look at
         the previous hop of circuits that ask to open an exit stream,
         and refuse to exit if they don't recognize it as a relay. The
         goal is to make it harder for people to use them as one-hop
         proxies. See trac entry 1751 for details.
+        Min: 0, Max: 1
 
         See also "2.4.5. Consensus parameters governing behavior"
         in path-spec.txt for a series of circuit build time related
@@ -1820,7 +1824,7 @@
 
   To ensure consensus, all calculations are performed using integer math
   with a fixed precision determined by the bwweightscale consensus
-  parameter (defaults at 10000).
+  parameter (defaults at 10000, Min: 1, Max: INT32_MAX).
 
   For future balancing improvements, Tor clients support 11 additional weights
   for directory requests and middle weighting. These weights are currently
diff --git a/doc/spec/path-spec.txt b/doc/spec/path-spec.txt
index 2e4207bd56..7c313f8ab0 100644
--- a/doc/spec/path-spec.txt
+++ b/doc/spec/path-spec.txt
@@ -421,57 +421,79 @@ of their choices.
 
       cbtdisabled
         Default: 0
-        Effect: If non-zero, all CircuitBuildTime learning code should be
+        Min: 0
+        Max: 1
+        Effect: If 1, all CircuitBuildTime learning code should be
                 disabled and history should be discarded. For use in
                 emergency situations only.
 
       cbtnummodes
         Default: 3
+        Min: 1
+        Max: 20
         Effect: This value governs how many modes to use in the weighted
-        average calculation of Pareto paramter Xm. A value of 3 introduces
+        average calculation of Pareto parameter Xm. A value of 3 introduces
         some bias (2-5% of CDF) under ideal conditions, but allows for better
         performance in the event that a client chooses guard nodes of radically
         different performance characteristics.
 
       cbtrecentcount
         Default: 20
+        Min: 3
+        Max: 1000
         Effect: This is the number of circuit build times to keep track of
                 for the following option.
 
       cbtmaxtimeouts
         Default: 18
+        Min: 3
+        Max: 10000
         Effect: When this many timeouts happen in the last 'cbtrecentcount'
                 circuit attempts, the client should discard all of its
                 history and begin learning a fresh timeout value.
 
       cbtmincircs
         Default: 100
+        Min: 1
+        Max: 10000
         Effect: This is the minimum number of circuits to build before
                 computing a timeout.
 
       cbtquantile
         Default: 80
+        Min: 10
+        Max: 99
         Effect: This is the position on the quantile curve to use to set the
-                timeout value. It is a percent (0-99).
+                timeout value. It is a percent (10-99).
 
       cbtclosequantile
         Default: 95
+        Min: Value of cbtquantile parameter
+        Max: 99
         Effect: This is the position on the quantile curve to use to set the
                 timeout value to use to actually close circuits. It is a percent
                 (0-99).
 
       cbttestfreq
         Default: 60
+        Min: 1
+        Max: 2147483647 (INT32_MAX)
         Effect: Describes how often in seconds to build a test circuit to
                 gather timeout values. Only applies if less than 'cbtmincircs'
                 have been recorded.
 
       cbtmintimeout
         Default: 2000
+        Min: 500
+        Max: 2147483647 (INT32_MAX)
         Effect: This is the minimum allowed timeout value in milliseconds.
+                The minimum is to prevent rounding to 0 (we only check once
+                per second).
 
       cbtinitialtimeout
         Default: 60000
+        Min: Value of cbtmintimeout
+        Max: 2147483647 (INT32_MAX)
         Effect: This is the timeout value to use before computing a timeout,
                 in milliseconds.
 
diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index b1743847c8..3788959556 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -106,7 +106,7 @@ circuit_build_times_disabled(void)
     return 0;
   } else {
     int consensus_disabled = networkstatus_get_param(NULL, "cbtdisabled",
-                                                     0);
+                                                     0, 0, 1);
     int config_disabled = !get_options()->LearnCircuitBuildTimeout;
     int dirauth_disabled = get_options()->AuthoritativeDir;
     int state_disabled = (get_or_state()->LastWritten == -1);
@@ -128,16 +128,19 @@ circuit_build_times_disabled(void)
 static int32_t
 circuit_build_times_max_timeouts(void)
 {
-  int32_t num = networkstatus_get_param(NULL, "cbtmaxtimeouts",
-          CBT_DEFAULT_MAX_RECENT_TIMEOUT_COUNT);
-  return num;
+  return networkstatus_get_param(NULL, "cbtmaxtimeouts",
+                                 CBT_DEFAULT_MAX_RECENT_TIMEOUT_COUNT,
+                                 CBT_MIN_MAX_RECENT_TIMEOUT_COUNT,
+                                 CBT_MAX_MAX_RECENT_TIMEOUT_COUNT);
 }
 
 static int32_t
 circuit_build_times_default_num_xm_modes(void)
 {
   int32_t num = networkstatus_get_param(NULL, "cbtnummodes",
-          CBT_DEFAULT_NUM_XM_MODES);
+                                        CBT_DEFAULT_NUM_XM_MODES,
+                                        CBT_MIN_NUM_XM_MODES,
+                                        CBT_MAX_NUM_XM_MODES);
   return num;
 }
 
@@ -145,7 +148,9 @@ static int32_t
 circuit_build_times_min_circs_to_observe(void)
 {
   int32_t num = networkstatus_get_param(NULL, "cbtmincircs",
-                CBT_DEFAULT_MIN_CIRCUITS_TO_OBSERVE);
+                                        CBT_DEFAULT_MIN_CIRCUITS_TO_OBSERVE,
+                                        CBT_MIN_MIN_CIRCUITS_TO_OBSERVE,
+                                        CBT_MAX_MIN_CIRCUITS_TO_OBSERVE);
   return num;
 }
 
@@ -161,24 +166,46 @@ double
 circuit_build_times_quantile_cutoff(void)
 {
   int32_t num = networkstatus_get_param(NULL, "cbtquantile",
-                CBT_DEFAULT_QUANTILE_CUTOFF);
+                                        CBT_DEFAULT_QUANTILE_CUTOFF,
+                                        CBT_MIN_QUANTILE_CUTOFF,
+                                        CBT_MAX_QUANTILE_CUTOFF);
   return num/100.0;
 }
 
+int
+circuit_build_times_get_bw_scale(networkstatus_t *ns)
+{
+  return networkstatus_get_param(ns, "bwweightscale",
+                                 BW_WEIGHT_SCALE,
+                                 BW_MIN_WEIGHT_SCALE,
+                                 BW_MAX_WEIGHT_SCALE);
+}
+
 static double
 circuit_build_times_close_quantile(void)
 {
-  int32_t num = networkstatus_get_param(NULL, "cbtclosequantile",
-          CBT_DEFAULT_CLOSE_QUANTILE);
-
-  return num/100.0;
+  int32_t param;
+  /* Cast is safe - circuit_build_times_quantile_cutoff() is capped */
+  int32_t min = (int)tor_lround(100*circuit_build_times_quantile_cutoff());
+  param = networkstatus_get_param(NULL, "cbtclosequantile",
+             CBT_DEFAULT_CLOSE_QUANTILE,
+             CBT_MIN_CLOSE_QUANTILE,
+             CBT_MAX_CLOSE_QUANTILE);
+  if (param < min) {
+    log_warn(LD_DIR, "Consensus parameter cbtclosequantile is "
+             "too small, raising to %d", min);
+    param = min;
+  }
+  return param / 100.0;
 }
 
 static int32_t
 circuit_build_times_test_frequency(void)
 {
   int32_t num = networkstatus_get_param(NULL, "cbttestfreq",
-                CBT_DEFAULT_TEST_FREQUENCY);
+                                        CBT_DEFAULT_TEST_FREQUENCY,
+                                        CBT_MIN_TEST_FREQUENCY,
+                                        CBT_MAX_TEST_FREQUENCY);
   return num;
 }
 
@@ -186,24 +213,35 @@ static int32_t
 circuit_build_times_min_timeout(void)
 {
   int32_t num = networkstatus_get_param(NULL, "cbtmintimeout",
-                CBT_DEFAULT_TIMEOUT_MIN_VALUE);
+                                        CBT_DEFAULT_TIMEOUT_MIN_VALUE,
+                                        CBT_MIN_TIMEOUT_MIN_VALUE,
+                                        CBT_MAX_TIMEOUT_MIN_VALUE);
   return num;
 }
 
 int32_t
 circuit_build_times_initial_timeout(void)
 {
-  int32_t num = networkstatus_get_param(NULL, "cbtinitialtimeout",
-                CBT_DEFAULT_TIMEOUT_INITIAL_VALUE);
-  return num;
+  int32_t min = circuit_build_times_min_timeout();
+  int32_t param = networkstatus_get_param(NULL, "cbtinitialtimeout",
+                                          CBT_DEFAULT_TIMEOUT_INITIAL_VALUE,
+                                          CBT_MIN_TIMEOUT_INITIAL_VALUE,
+                                          CBT_MAX_TIMEOUT_INITIAL_VALUE);
+  if (param < min) {
+    log_warn(LD_DIR, "Consensus parameter cbtinitialtimeout is too small, "
+             "raising to %d", min);
+    param = min;
+  }
+  return param;
 }
 
 static int32_t
-circuit_build_times_recent_circuit_count(void)
+circuit_build_times_recent_circuit_count(networkstatus_t *ns)
 {
-  int32_t num = networkstatus_get_param(NULL, "cbtrecentcount",
-                CBT_DEFAULT_RECENT_CIRCUITS);
-  return num;
+  return networkstatus_get_param(ns, "cbtrecentcount",
+                                 CBT_DEFAULT_RECENT_CIRCUITS,
+                                 CBT_MIN_RECENT_CIRCUITS,
+                                 CBT_MAX_RECENT_CIRCUITS);
 }
 
 /**
@@ -216,8 +254,7 @@ void
 circuit_build_times_new_consensus_params(circuit_build_times_t *cbt,
                                          networkstatus_t *ns)
 {
-  int32_t num = networkstatus_get_param(ns, "cbtrecentcount",
-                   CBT_DEFAULT_RECENT_CIRCUITS);
+  int32_t num = circuit_build_times_recent_circuit_count(ns);
 
   if (num > 0 && num != cbt->liveness.num_recent_circs) {
     int8_t *recent_circs;
@@ -307,7 +344,8 @@ void
 circuit_build_times_init(circuit_build_times_t *cbt)
 {
   memset(cbt, 0, sizeof(*cbt));
-  cbt->liveness.num_recent_circs = circuit_build_times_recent_circuit_count();
+  cbt->liveness.num_recent_circs =
+      circuit_build_times_recent_circuit_count(NULL);
   cbt->liveness.timeouts_after_firsthop = tor_malloc_zero(sizeof(int8_t)*
                                       cbt->liveness.num_recent_circs);
   cbt->close_ms = cbt->timeout_ms = circuit_build_times_get_initial_timeout();
diff --git a/src/or/circuitbuild.h b/src/or/circuitbuild.h
index 74bbd4f22a..af24931878 100644
--- a/src/or/circuitbuild.h
+++ b/src/or/circuitbuild.h
@@ -121,5 +121,7 @@ void circuit_build_times_network_is_live(circuit_build_times_t *cbt);
 int circuit_build_times_network_check_live(circuit_build_times_t *cbt);
 void circuit_build_times_network_circ_success(circuit_build_times_t *cbt);
 
+int circuit_build_times_get_bw_scale(networkstatus_t *ns);
+
 #endif
 
diff --git a/src/or/circuitlist.c b/src/or/circuitlist.c
index 58ff27e5e1..b4f5f45615 100644
--- a/src/or/circuitlist.c
+++ b/src/or/circuitlist.c
@@ -384,7 +384,9 @@ circuit_purpose_to_controller_string(uint8_t purpose)
 int32_t
 circuit_initial_package_window(void)
 {
-  int32_t num = networkstatus_get_param(NULL, "circwindow", CIRCWINDOW_START);
+  int32_t num = networkstatus_get_param(NULL, "circwindow", CIRCWINDOW_START,
+                                        CIRCWINDOW_START_MIN,
+                                        CIRCWINDOW_START_MAX);
   /* If the consensus tells us a negative number, we'd assert. */
   if (num < 0)
     num = CIRCWINDOW_START;
diff --git a/src/or/connection_or.c b/src/or/connection_or.c
index cf7c09a3cd..b93699ccc1 100644
--- a/src/or/connection_or.c
+++ b/src/or/connection_or.c
@@ -370,11 +370,11 @@ connection_or_update_token_buckets_helper(or_connection_t *conn, int reset,
      * bandwidth parameters in the consensus, but allow local config
      * options to override. */
     rate = options->PerConnBWRate ? (int)options->PerConnBWRate :
-        (int)networkstatus_get_param(NULL, "perconnbwrate",
-                                     (int)options->BandwidthRate);
+        networkstatus_get_param(NULL, "perconnbwrate",
+                                (int)options->BandwidthRate, 1, INT32_MAX);
     burst = options->PerConnBWBurst ? (int)options->PerConnBWBurst :
-        (int)networkstatus_get_param(NULL, "perconnbwburst",
-                                     (int)options->BandwidthBurst);
+        networkstatus_get_param(NULL, "perconnbwburst",
+                                (int)options->BandwidthBurst, 1, INT32_MAX);
   }
 
   conn->bandwidthrate = rate;
diff --git a/src/or/dirvote.h b/src/or/dirvote.h
index cd5fe86bc1..67540a37fb 100644
--- a/src/or/dirvote.h
+++ b/src/or/dirvote.h
@@ -19,9 +19,6 @@
 /** Smallest allowable voting interval. */
 #define MIN_VOTE_INTERVAL 300
 
-/** Precision multiplier for the Bw weights */
-#define BW_WEIGHT_SCALE   10000
-
 void dirvote_free_all(void);
 
 /* vote manipulation */
diff --git a/src/or/networkstatus.c b/src/or/networkstatus.c
index dfc3a45f76..687ac03fa0 100644
--- a/src/or/networkstatus.c
+++ b/src/or/networkstatus.c
@@ -2125,32 +2125,52 @@ networkstatus_dump_bridge_status_to_file(time_t now)
   tor_free(status);
 }
 
-int32_t
+static int32_t
 get_net_param_from_list(smartlist_t *net_params, const char *param_name,
-                        int default_val)
+                        int32_t default_val, int32_t min_val, int32_t max_val)
 {
+  int32_t res = default_val;
   size_t name_len = strlen(param_name);
 
+  tor_assert(max_val > min_val);
+  tor_assert(min_val <= default_val);
+  tor_assert(max_val >= default_val);
+
   SMARTLIST_FOREACH_BEGIN(net_params, const char *, p) {
     if (!strcmpstart(p, param_name) && p[name_len] == '=') {
       int ok=0;
       long v = tor_parse_long(p+name_len+1, 10, INT32_MIN,
                               INT32_MAX, &ok, NULL);
-      if (ok)
-        return (int32_t) v;
+      if (ok) {
+        res = (int32_t) v;
+        break;
+      }
     }
   } SMARTLIST_FOREACH_END(p);
 
-  return default_val;
+  if (res < min_val) {
+    log_warn(LD_DIR, "Consensus parameter %s is too small. Got %d, raising to "
+             "%d.", param_name, res, min_val);
+    res = min_val;
+  } else if (res > max_val) {
+    log_warn(LD_DIR, "Consensus parameter %s is too large. Got %d, capping to "
+             "%d.", param_name, res, max_val);
+    res = max_val;
+  }
+
+  return res;
 }
 
 /** Return the value of a integer parameter from the networkstatus <b>ns</b>
  * whose name is <b>param_name</b>.  If <b>ns</b> is NULL, try loading the
  * latest consensus ourselves. Return <b>default_val</b> if no latest
- * consensus, or if it has no parameter called <b>param_name</b>. */
+ * consensus, or if it has no parameter called <b>param_name</b>.
+ * Make sure the value parsed from the consensus is at least
+ * <b>min_val</b> and at most <b>max_val</b> and raise/cap the parsed value
+ * if necessary. */
 int32_t
 networkstatus_get_param(networkstatus_t *ns, const char *param_name,
-                        int32_t default_val)
+                        int32_t default_val, int32_t min_val, int32_t max_val)
 {
   if (!ns) /* if they pass in null, go find it ourselves */
     ns = networkstatus_get_latest_consensus();
@@ -2158,24 +2178,36 @@ networkstatus_get_param(networkstatus_t *ns, const char *param_name,
   if (!ns || !ns->net_params)
     return default_val;
 
-  return get_net_param_from_list(ns->net_params, param_name, default_val);
+  return get_net_param_from_list(ns->net_params, param_name,
+                                 default_val, min_val, max_val);
 }
 
 /** Return the value of a integer bw weight parameter from the networkstatus
  * <b>ns</b> whose name is <b>weight_name</b>.  If <b>ns</b> is NULL, try
  * loading the latest consensus ourselves. Return <b>default_val</b> if no
- * latest consensus, or if it has no parameter called <b>param_name</b>. */
+ * latest consensus, or if it has no parameter called <b>weight_name</b>. */
 int32_t
 networkstatus_get_bw_weight(networkstatus_t *ns, const char *weight_name,
-                        int32_t default_val)
+                            int32_t default_val)
 {
+  int32_t param;
+  int max;
   if (!ns) /* if they pass in null, go find it ourselves */
     ns = networkstatus_get_latest_consensus();
 
   if (!ns || !ns->weight_params)
     return default_val;
 
-  return get_net_param_from_list(ns->weight_params, weight_name, default_val);
+  max = circuit_build_times_get_bw_scale(ns);
+  param = get_net_param_from_list(ns->weight_params, weight_name,
+                                  default_val, -1,
+                                  BW_MAX_WEIGHT_SCALE);
+  if (param > max) {
+    log_warn(LD_DIR, "Value of consensus weight %s was too large, capping "
+             "to %d", weight_name, max);
+    param = max;
+  }
+  return param;
 }
 
 /** Return the name of the consensus flavor <b>flav</b> as used to identify
diff --git a/src/or/networkstatus.h b/src/or/networkstatus.h
index 2f18dc9525..ec2e8f884d 100644
--- a/src/or/networkstatus.h
+++ b/src/or/networkstatus.h
@@ -81,10 +81,9 @@ void signed_descs_update_status_from_consensus_networkstatus(
 char *networkstatus_getinfo_helper_single(routerstatus_t *rs);
 char *networkstatus_getinfo_by_purpose(const char *purpose_string, time_t now);
 void networkstatus_dump_bridge_status_to_file(time_t now);
-int32_t get_net_param_from_list(smartlist_t *net_params, const char *name,
-                                int default_val);
 int32_t networkstatus_get_param(networkstatus_t *ns, const char *param_name,
-                                int32_t default_val);
+                                int32_t default_val, int32_t min_val,
+                                int32_t max_val);
 int getinfo_helper_networkstatus(control_connection_t *conn,
                                  const char *question, char **answer,
                                  const char **errmsg);
diff --git a/src/or/or.h b/src/or/or.h
index cb36126d99..22c8498b66 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -765,6 +765,8 @@ typedef enum {
 /** Initial value for both sides of a circuit transmission window when the
  * circuit is initialized.  Measured in cells. */
 #define CIRCWINDOW_START 1000
+#define CIRCWINDOW_START_MIN 100
+#define CIRCWINDOW_START_MAX 1000
 /** Amount to increment a circuit window when we get a circuit SENDME. */
 #define CIRCWINDOW_INCREMENT 100
 /** Initial value on both sides of a stream transmission window when the
@@ -2942,6 +2944,11 @@ struct socks_request_t {
 
 /* Circuit Build Timeout "public" structures. */
 
+/** Precision multiplier for the Bw weights */
+#define BW_WEIGHT_SCALE   10000
+#define BW_MIN_WEIGHT_SCALE 1
+#define BW_MAX_WEIGHT_SCALE INT32_MAX
+
 /** Total size of the circuit timeout history to accumulate.
  * 1000 is approx 2.5 days worth of continual-use circuits. */
 #define CBT_NCIRCUITS_TO_OBSERVE 1000
@@ -2951,6 +2958,8 @@ struct socks_request_t {
 
 /** Number of modes to use in the weighted-avg computation of Xm */
 #define CBT_DEFAULT_NUM_XM_MODES 3
+#define CBT_MIN_NUM_XM_MODES 1
+#define CBT_MAX_NUM_XM_MODES 20
 
 /** A build_time_t is milliseconds */
 typedef uint32_t build_time_t;
@@ -2972,12 +2981,16 @@ typedef uint32_t build_time_t;
  * build in terms of CDF quantile.
  */
 #define CBT_DEFAULT_CLOSE_QUANTILE 95
+#define CBT_MIN_CLOSE_QUANTILE CBT_MIN_QUANTILE_CUTOFF
+#define CBT_MAX_CLOSE_QUANTILE CBT_MAX_QUANTILE_CUTOFF
 
 /**
  * How many circuits count as recent when considering if the
  * connection has gone gimpy or changed.
  */
 #define CBT_DEFAULT_RECENT_CIRCUITS 20
+#define CBT_MIN_RECENT_CIRCUITS 3
+#define CBT_MAX_RECENT_CIRCUITS 1000
 
 /**
  * Maximum count of timeouts that finish the first hop in the past
@@ -2988,25 +3001,37 @@ typedef uint32_t build_time_t;
  * gives us.
  */
 #define CBT_DEFAULT_MAX_RECENT_TIMEOUT_COUNT (CBT_DEFAULT_RECENT_CIRCUITS*9/10)
+#define CBT_MIN_MAX_RECENT_TIMEOUT_COUNT 3
+#define CBT_MAX_MAX_RECENT_TIMEOUT_COUNT 10000
 
 /** Minimum circuits before estimating a timeout */
 #define CBT_DEFAULT_MIN_CIRCUITS_TO_OBSERVE 100
+#define CBT_MIN_MIN_CIRCUITS_TO_OBSERVE 1
+#define CBT_MAX_MIN_CIRCUITS_TO_OBSERVE 10000
 
 /** Cutoff percentile on the CDF for our timeout estimation. */
 #define CBT_DEFAULT_QUANTILE_CUTOFF 80
+#define CBT_MIN_QUANTILE_CUTOFF 10
+#define CBT_MAX_QUANTILE_CUTOFF 99
 double circuit_build_times_quantile_cutoff(void);
 
 /** How often in seconds should we build a test circuit */
 #define CBT_DEFAULT_TEST_FREQUENCY 60
+#define CBT_MIN_TEST_FREQUENCY 1
+#define CBT_MAX_TEST_FREQUENCY INT32_MAX
 
 /** Lowest allowable value for CircuitBuildTimeout in milliseconds */
 #define CBT_DEFAULT_TIMEOUT_MIN_VALUE (1500)
+#define CBT_MIN_TIMEOUT_MIN_VALUE 500
+#define CBT_MAX_TIMEOUT_MIN_VALUE INT32_MAX
 
 /** Initial circuit build timeout in milliseconds */
 #define CBT_DEFAULT_TIMEOUT_INITIAL_VALUE (60*1000)
+#define CBT_MIN_TIMEOUT_INITIAL_VALUE CBT_MIN_TIMEOUT_MIN_VALUE
+#define CBT_MAX_TIMEOUT_INITIAL_VALUE INT32_MAX
 int32_t circuit_build_times_initial_timeout(void);
 
-#if CBT_DEFAULT_MAX_RECENT_TIMEOUT_COUNT < 1
+#if CBT_DEFAULT_MAX_RECENT_TIMEOUT_COUNT < CBT_MIN_MAX_RECENT_TIMEOUT_COUNT
 #error "RECENT_CIRCUITS is set too low."
 #endif
 
diff --git a/src/or/relay.c b/src/or/relay.c
index 32ac96edf4..a6c25062a3 100644
--- a/src/or/relay.c
+++ b/src/or/relay.c
@@ -1999,9 +1999,9 @@ cell_ewma_set_scale_factor(or_options_t *options, networkstatus_t *consensus)
   if (options && options->CircuitPriorityHalflife >= -EPSILON) {
     halflife = options->CircuitPriorityHalflife;
     source = "CircuitPriorityHalflife in configuration";
-  } else if (consensus &&
-             (halflife_ms = networkstatus_get_param(
-                   consensus, "CircuitPriorityHalflifeMsec", -1)) >= 0) {
+  } else if (consensus && (halflife_ms = networkstatus_get_param(
+                 consensus, "CircuitPriorityHalflifeMsec",
+                 -1, -1, INT32_MAX)) >= 0) {
     halflife = ((double)halflife_ms)/1000.0;
     source = "CircuitPriorityHalflifeMsec in consensus";
   } else {
diff --git a/src/or/router.c b/src/or/router.c
index 3bb37de8cf..26ac351fc4 100644
--- a/src/or/router.c
+++ b/src/or/router.c
@@ -1068,7 +1068,7 @@ should_refuse_unknown_exits(or_options_t *options)
   if (options->RefuseUnknownExits_ != -1) {
     return options->RefuseUnknownExits_;
   } else {
-    return networkstatus_get_param(NULL, "refuseunknownexits", 1);
+    return networkstatus_get_param(NULL, "refuseunknownexits", 1, 0, 1);
   }
 }
 
diff --git a/src/or/routerlist.c b/src/or/routerlist.c
index e29b4c49d8..47caebf8df 100644
--- a/src/or/routerlist.c
+++ b/src/or/routerlist.c
@@ -1650,8 +1650,7 @@ smartlist_choose_by_bandwidth_weights(smartlist_t *sl,
     return NULL;
   }
 
-  weight_scale = networkstatus_get_param(NULL, "bwweightscale",
-                                         BW_WEIGHT_SCALE);
+  weight_scale = circuit_build_times_get_bw_scale(NULL);
 
   if (rule == WEIGHT_FOR_GUARD) {
     Wg = networkstatus_get_bw_weight(NULL, "Wgg", -1);
diff --git a/src/or/routerparse.c b/src/or/routerparse.c
index a6eef2df6c..08f81d9f76 100644
--- a/src/or/routerparse.c
+++ b/src/or/routerparse.c
@@ -11,6 +11,7 @@
 
 #include "or.h"
 #include "config.h"
+#include "circuitbuild.h"
 #include "dirserv.h"
 #include "dirvote.h"
 #include "policies.h"
@@ -2373,7 +2374,7 @@ networkstatus_verify_bw_weights(networkstatus_t *ns)
   const char *casename = NULL;
   int valid = 1;
 
-  weight_scale = networkstatus_get_param(ns, "bwweightscale", BW_WEIGHT_SCALE);
+  weight_scale = circuit_build_times_get_bw_scale(ns);
   Wgg = networkstatus_get_bw_weight(ns, "Wgg", -1);
   Wgm = networkstatus_get_bw_weight(ns, "Wgm", -1);
   Wgd = networkstatus_get_bw_weight(ns, "Wgd", -1);
diff --git a/src/test/test_dir.c b/src/test/test_dir.c
index e61815027c..1f3beb4baa 100644
--- a/src/test/test_dir.c
+++ b/src/test/test_dir.c
@@ -609,8 +609,11 @@ test_dir_param_voting(void)
                          "abcd=20 c=60 cw=500 x-yz=-9 zzzzz=101", NULL, 0, 0);
   smartlist_split_string(vote4.net_params,
                          "ab=900 abcd=200 c=1 cw=51 x-yz=100", NULL, 0, 0);
-  test_eq(100, networkstatus_get_param(&vote4, "x-yz", 50));
-  test_eq(222, networkstatus_get_param(&vote4, "foobar", 222));
+  test_eq(100, networkstatus_get_param(&vote4, "x-yz", 50, 0, 300));
+  test_eq(222, networkstatus_get_param(&vote4, "foobar", 222, 0, 300));
+  test_eq(80, networkstatus_get_param(&vote4, "ab", 12, 0, 80));
+  test_eq(-8, networkstatus_get_param(&vote4, "ab", -12, -100, -8));
+  test_eq(0, networkstatus_get_param(&vote4, "foobar", 0, -100, 8));
 
   smartlist_add(votes, &vote1);
   smartlist_add(votes, &vote2);