From 79e3c477f8d0d8ea397820847c576e0a0aaa5323 Mon Sep 17 00:00:00 2001
From: Hans Nilsson <hans@erlang.org>
Date: Thu, 3 May 2018 13:48:39 +0200
Subject: ssh: Extend rekey_limit to also take an optional time

---
 lib/ssh/src/ssh.hrl                    |  5 +++--
 lib/ssh/src/ssh_connection_handler.erl | 17 ++++++++++-------
 lib/ssh/src/ssh_options.erl            | 16 +++++++++++++---
 3 files changed, 26 insertions(+), 12 deletions(-)

(limited to 'lib/ssh/src')

diff --git a/lib/ssh/src/ssh.hrl b/lib/ssh/src/ssh.hrl
index a3d9a1b1cb..fc0a3786ac 100644
--- a/lib/ssh/src/ssh.hrl
+++ b/lib/ssh/src/ssh.hrl
@@ -29,7 +29,6 @@
 
 -define(SSH_DEFAULT_PORT, 22).
 -define(SSH_MAX_PACKET_SIZE, (256*1024)).
--define(REKEY_TIMOUT, 3600000).
 -define(REKEY_DATA_TIMOUT, 60000).
 -define(DEFAULT_PROFILE, default).
 
@@ -192,7 +191,9 @@
 -type user_dir_common_option()      :: {user_dir,  false | string()}.
 -type profile_common_option()       :: {profile,   atom() }.
 -type max_idle_time_common_option() :: {idle_time, timeout()}.
--type rekey_limit_common_option()   :: {rekey_limit, non_neg_integer() }.
+-type rekey_limit_common_option()   :: {rekey_limit, Bytes::non_neg_integer() |
+                                                     {Minutes::non_neg_integer(), Bytes::non_neg_integer()}
+                                       }.
 
 -type key_cb_common_option()            :: {key_cb,  Module::atom() | {Module::atom(),Opts::[term()]} } .
 -type disconnectfun_common_option()     ::
diff --git a/lib/ssh/src/ssh_connection_handler.erl b/lib/ssh/src/ssh_connection_handler.erl
index 57641cf74c..b21c0337ad 100644
--- a/lib/ssh/src/ssh_connection_handler.erl
+++ b/lib/ssh/src/ssh_connection_handler.erl
@@ -429,9 +429,6 @@ init([Role,Socket,Opts]) ->
               },
             D = case Role of
                     client ->
-                        %% Start the renegotiation timers
-                        timer:apply_after(?REKEY_TIMOUT,      gen_statem, cast, [self(), renegotiate]),
-                        timer:apply_after(?REKEY_DATA_TIMOUT, gen_statem, cast, [self(), data_size]),
                         cache_init_idle_timer(D0);
                     server ->
                         Sups = ?GET_INTERNAL_OPT(supervisors, Opts),
@@ -444,6 +441,10 @@ init([Role,Socket,Opts]) ->
                                                    connection_supervisor = proplists:get_value(connection_sup, Sups)
                                                   }})
                 end,
+            %% Start the renegotiation timers
+            {RekeyTimeout,_MaxSent} = ?GET_OPT(rekey_limit, (D#data.ssh_params)#ssh.opts),
+            timer:apply_after(RekeyTimeout,       gen_statem, cast, [self(), renegotiate]),
+            timer:apply_after(?REKEY_DATA_TIMOUT, gen_statem, cast, [self(), data_size]),
             {ok, {hello,Role}, D};
         
         {error,Error} ->
@@ -1066,7 +1067,8 @@ handle_event(internal, Msg=#ssh_msg_channel_failure{},           StateName, D) -
 handle_event(cast, renegotiate, {connected,Role}, D) ->
     {KeyInitMsg, SshPacket, Ssh} = ssh_transport:key_exchange_init_msg(D#data.ssh_params),
     send_bytes(SshPacket, D),
-    timer:apply_after(?REKEY_TIMOUT, gen_statem, cast, [self(), renegotiate]),
+    {RekeyTimeout,_MaxSent} = ?GET_OPT(rekey_limit, Ssh#ssh.opts),
+    timer:apply_after(RekeyTimeout, gen_statem, cast, [self(), renegotiate]),
     {next_state, {kexinit,Role,renegotiate}, D#data{ssh_params = Ssh,
 						    key_exchange_init_msg = KeyInitMsg}};
 
@@ -1074,9 +1076,10 @@ handle_event({call,From}, get_alg, _, D) ->
     #ssh{algorithms=Algs} = D#data.ssh_params,
     {keep_state_and_data, [{reply,From,Algs}]};
 
-handle_event(cast, renegotiate, _, _) ->
+handle_event(cast, renegotiate, _, D) ->
     %% Already in key-exchange so safe to ignore
-    timer:apply_after(?REKEY_TIMOUT, gen_statem, cast, [self(), renegotiate]), % FIXME: not here in original
+    {RekeyTimeout,_MaxSent} = ?GET_OPT(rekey_limit, (D#data.ssh_params)#ssh.opts),
+    timer:apply_after(RekeyTimeout, gen_statem, cast, [self(), renegotiate]),
     keep_state_and_data;
 
 
@@ -1084,7 +1087,7 @@ handle_event(cast, renegotiate, _, _) ->
 handle_event(cast, data_size, {connected,Role}, D) ->
     {ok, [{send_oct,Sent0}]} = inet:getstat(D#data.socket, [send_oct]),
     Sent = Sent0 - D#data.last_size_rekey,
-    MaxSent = ?GET_OPT(rekey_limit, (D#data.ssh_params)#ssh.opts),
+    {_RekeyTimeout,MaxSent} = ?GET_OPT(rekey_limit, (D#data.ssh_params)#ssh.opts),
     timer:apply_after(?REKEY_DATA_TIMOUT, gen_statem, cast, [self(), data_size]),
     case Sent >= MaxSent of
 	true ->
diff --git a/lib/ssh/src/ssh_options.erl b/lib/ssh/src/ssh_options.erl
index 4dd9082250..73287e464a 100644
--- a/lib/ssh/src/ssh_options.erl
+++ b/lib/ssh/src/ssh_options.erl
@@ -599,9 +599,19 @@ default(common) ->
              class => user_options
             },
 
-      {rekey_limit, def} =>                     % FIXME: Why not common?
-          #{default => 1024000000,
-            chk => fun check_non_neg_integer/1,
+      {rekey_limit, def} =>
+          #{default => {3600000, 1024000000}, % {1 hour, 1 GB}
+            chk => fun({TimeMins, SizBytes}) when is_integer(TimeMins) andalso TimeMins>=0,
+                                                  is_integer(SizBytes) andalso SizBytes>=0 ->
+                           %% New (>= 21) format
+                           {true, {TimeMins * 60*1000, % To ms
+                                   SizBytes}};
+                      (SizBytes) when is_integer(SizBytes) andalso SizBytes>=0 ->
+                           %% Old (< 21) format
+                           {true, {3600000, SizBytes}};
+                      (_) ->
+                           false
+                   end,
             class => user_options
            },
 
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