@@ -33,7 +33,7 @@

 .\" .ft -- normal face

 .\" .in +|-{n} -- indent

 .\"

-.TH openvpn 8 "25 August 2016"

+.TH openvpn 8 "04 April 2017"

 .\"*********************************************************

 .SH NAME

 openvpn \- secure IP tunnel daemon.

@@ -4957,10 +4957,26 @@ Renegotiate data channel key after

 packets sent and received (disabled by default).

 .\"*********************************************************

 .TP

-.B \-\-reneg\-sec n

-Renegotiate data channel key after

-.B n

-seconds (default=3600).

+.B \-\-reneg\-sec max [min]

+Renegotiate data channel key after at most

+.B max

+seconds (default=3600) and at least

+.B min

+seconds (default is 90% of

+.B max

+for servers, and equal to

+.B max

+for clients).

+

+The effective

+.B reneg\-sec

+value used is per session pseudo-uniform-randomized between

+.B min

+and

+.B max\fR.

+

+With the default value of 3600 this results in an effective per session value

+in the range of 3240..3600 seconds for servers, or just 3600 for clients.

 When using dual\-factor authentication, note that this default value may

 cause the end user to be challenged to reauthorize once per hour.

@@ -2693,7 +2693,20 @@ do_init_crypto_tls(struct context *c, const unsigned int flags)

     to.packet_timeout = options->tls_timeout;

     to.renegotiate_bytes = options->renegotiate_bytes;

     to.renegotiate_packets = options->renegotiate_packets;

-    to.renegotiate_seconds = options->renegotiate_seconds;

+    if (options->renegotiate_seconds_min < 0)

+    {

+        /* Add 10% jitter to reneg-sec by default (server side only) */

+        int auto_jitter = options->mode != MODE_SERVER ? 0 :

+                get_random() % max_int(options->renegotiate_seconds / 10, 1);

+        to.renegotiate_seconds = options->renegotiate_seconds - auto_jitter;

+    }

+    else

+    {

+        /* Add user-specified jitter to reneg-sec */

+        to.renegotiate_seconds = options->renegotiate_seconds -

+                (get_random() % max_int(options->renegotiate_seconds

+                                        - options->renegotiate_seconds_min, 1));

+    }

     to.single_session = options->single_session;

     to.mode = options->mode;

     to.pull = options->pull;

@@ -603,7 +603,9 @@ static const char usage_message[] =

     "                  if no ACK from remote within n seconds (default=%d).\n"

     "--reneg-bytes n : Renegotiate data chan. key after n bytes sent and recvd.\n"

     "--reneg-pkts n  : Renegotiate data chan. key after n packets sent and recvd.\n"

-    "--reneg-sec n   : Renegotiate data chan. key after n seconds (default=%d).\n"

+    "--reneg-sec max [min] : Renegotiate data chan. key after at most max (default=%d)\n"

+    "                  and at least min (defaults to 90%% of max on servers and equal\n"

+    "                  to max on clients).\n"

     "--hand-window n : Data channel key exchange must finalize within n seconds\n"

     "                  of handshake initiation by any peer (default=%d).\n"

     "--tran-window n : Transition window -- old key can live this many seconds\n"

@@ -870,6 +872,7 @@ init_options(struct options *o, const bool init_gc)

     o->tls_timeout = 2;

     o->renegotiate_bytes = -1;

     o->renegotiate_seconds = 3600;

+    o->renegotiate_seconds_min = -1;

     o->handshake_window = 60;

     o->transition_window = 3600;

     o->ecdh_curve = NULL;

@@ -8001,10 +8004,14 @@ add_option(struct options *options,

         VERIFY_PERMISSION(OPT_P_TLS_PARMS);

         options->renegotiate_packets = positive_atoi(p[1]);

     }

-    else if (streq(p[0], "reneg-sec") && p[1] && !p[2])

+    else if (streq(p[0], "reneg-sec") && p[1] && !p[3])

     {

         VERIFY_PERMISSION(OPT_P_TLS_PARMS);

         options->renegotiate_seconds = positive_atoi(p[1]);

+        if (p[2])

+        {

+            options->renegotiate_seconds_min = positive_atoi(p[2]);

+        }

     }

     else if (streq(p[0], "hand-window") && p[1] && !p[2])

     {

@@ -548,6 +548,7 @@ struct options

     int renegotiate_bytes;

     int renegotiate_packets;

     int renegotiate_seconds;

+    int renegotiate_seconds_min;

     /* Data channel key handshake must finalize

      * within n seconds of handshake initiation. */

@@ -2732,9 +2732,9 @@ tls_process(struct tls_multi *multi,

                 && ks->n_packets >= session->opt->renegotiate_packets)

             || (packet_id_close_to_wrapping(&ks->crypto_options.packet_id.send))))

     {

-        msg(D_TLS_DEBUG_LOW,

-            "TLS: soft reset sec=%d bytes=" counter_format "/%d pkts=" counter_format "/%d",

-            (int)(ks->established + session->opt->renegotiate_seconds - now),

+        msg(D_TLS_DEBUG_LOW, "TLS: soft reset sec=%d/%d bytes=" counter_format

+            "/%d pkts=" counter_format "/%d",

+            (int) (now - ks->established), session->opt->renegotiate_seconds,

             ks->n_bytes, session->opt->renegotiate_bytes,

             ks->n_packets, session->opt->renegotiate_packets);

         key_state_soft_reset(session);