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-rw-r--r--lib/ssl/doc/src/ssl.xml12
-rw-r--r--lib/ssl/src/dtls_connection.erl1
-rw-r--r--lib/ssl/src/ssl.erl11
-rw-r--r--lib/ssl/src/ssl_internal.hrl1
-rw-r--r--lib/ssl/src/tls_connection.erl1
-rw-r--r--lib/ssl/test/ssl_basic_SUITE.erl57
6 files changed, 76 insertions, 7 deletions
diff --git a/lib/ssl/doc/src/ssl.xml b/lib/ssl/doc/src/ssl.xml
index 0c042f8571..923ecdd618 100644
--- a/lib/ssl/doc/src/ssl.xml
+++ b/lib/ssl/doc/src/ssl.xml
@@ -514,6 +514,18 @@ fun(srp, Username :: string(), UserState :: term()) ->
using <c>negotiated_next_protocol/1</c> method.
</item>
+ <tag>{client_renegotiation, boolean()}</tag>
+ <item>In protocols that support client-initiated renegotiation, the cost
+ of resources of such an operation is higher for the server than the
+ client. This can act as a vector for denial of service attacks. The SSL
+ application already takes measures to counter-act such attempts,
+ but client-initiated renegotiation can be stricly disabled by setting
+ this option to <c>false</c>. The default value is <c>true</c>.
+ Note that disabling renegotiation can result in long-lived connections
+ becoming unusable due to limits on the number of messages the underlying
+ cipher suite can encipher.
+ </item>
+
<tag>{psk_identity, string()}</tag>
<item>Specifies the server identity hint the server presents to the client.
</item>
diff --git a/lib/ssl/src/dtls_connection.erl b/lib/ssl/src/dtls_connection.erl
index 508983ddac..039495ef9e 100644
--- a/lib/ssl/src/dtls_connection.erl
+++ b/lib/ssl/src/dtls_connection.erl
@@ -513,6 +513,7 @@ initial_state(Role, Host, Port, Socket, {SSLOptions, SocketOptions}, User,
user_data_buffer = <<>>,
session_cache_cb = SessionCacheCb,
renegotiation = {false, first},
+ allow_renegotiate = SSLOptions#ssl_options.client_renegotiation,
start_or_recv_from = undefined,
send_queue = queue:new(),
protocol_cb = ?MODULE
diff --git a/lib/ssl/src/ssl.erl b/lib/ssl/src/ssl.erl
index 5f4ad7f013..a141426d75 100644
--- a/lib/ssl/src/ssl.erl
+++ b/lib/ssl/src/ssl.erl
@@ -645,6 +645,7 @@ handle_options(Opts0) ->
reuse_session = handle_option(reuse_session, Opts, ReuseSessionFun),
reuse_sessions = handle_option(reuse_sessions, Opts, true),
secure_renegotiate = handle_option(secure_renegotiate, Opts, false),
+ client_renegotiation = handle_option(client_renegotiation, Opts, true),
renegotiate_at = handle_option(renegotiate_at, Opts, ?DEFAULT_RENEGOTIATE_AT),
hibernate_after = handle_option(hibernate_after, Opts, undefined),
erl_dist = handle_option(erl_dist, Opts, false),
@@ -667,9 +668,9 @@ handle_options(Opts0) ->
depth, cert, certfile, key, keyfile,
password, cacerts, cacertfile, dh, dhfile,
user_lookup_fun, psk_identity, srp_identity, ciphers,
- reuse_session, reuse_sessions, ssl_imp,
- cb_info, renegotiate_at, secure_renegotiate, hibernate_after,
- erl_dist, next_protocols_advertised,
+ reuse_session, reuse_sessions, ssl_imp, cb_info,
+ renegotiate_at, secure_renegotiate, client_renegotiation,
+ hibernate_after, erl_dist, next_protocols_advertised,
client_preferred_next_protocols, log_alert,
server_name_indication, honor_cipher_order, padding_check,
fallback],
@@ -796,6 +797,8 @@ validate_option(reuse_sessions, Value) when is_boolean(Value) ->
validate_option(secure_renegotiate, Value) when is_boolean(Value) ->
Value;
+validate_option(client_renegotiation, Value) when is_boolean(Value) ->
+ Value;
validate_option(renegotiate_at, Value) when is_integer(Value) ->
erlang:min(Value, ?DEFAULT_RENEGOTIATE_AT);
@@ -1128,6 +1131,8 @@ new_ssl_options([{renegotiate_at, Value} | Rest], #ssl_options{} = Opts, RecordC
new_ssl_options(Rest, Opts#ssl_options{ renegotiate_at = validate_option(renegotiate_at, Value)}, RecordCB);
new_ssl_options([{secure_renegotiate, Value} | Rest], #ssl_options{} = Opts, RecordCB) ->
new_ssl_options(Rest, Opts#ssl_options{secure_renegotiate = validate_option(secure_renegotiate, Value)}, RecordCB);
+new_ssl_options([{client_renegotiation, Value} | Rest], #ssl_options{} = Opts, RecordCB) ->
+ new_ssl_options(Rest, Opts#ssl_options{client_renegotiation = validate_option(client_renegotiation, Value)}, RecordCB);
new_ssl_options([{hibernate_after, Value} | Rest], #ssl_options{} = Opts, RecordCB) ->
new_ssl_options(Rest, Opts#ssl_options{hibernate_after = validate_option(hibernate_after, Value)}, RecordCB);
new_ssl_options([{next_protocols_advertised, Value} | Rest], #ssl_options{} = Opts, RecordCB) ->
diff --git a/lib/ssl/src/ssl_internal.hrl b/lib/ssl/src/ssl_internal.hrl
index 88105cac5a..a506fdf0a1 100644
--- a/lib/ssl/src/ssl_internal.hrl
+++ b/lib/ssl/src/ssl_internal.hrl
@@ -105,6 +105,7 @@
reuse_sessions :: boolean(),
renegotiate_at,
secure_renegotiate,
+ client_renegotiation,
%% undefined if not hibernating, or number of ms of
%% inactivity after which ssl_connection will go into
%% hibernation
diff --git a/lib/ssl/src/tls_connection.erl b/lib/ssl/src/tls_connection.erl
index 77d3aa7889..8abe73c585 100644
--- a/lib/ssl/src/tls_connection.erl
+++ b/lib/ssl/src/tls_connection.erl
@@ -384,6 +384,7 @@ initial_state(Role, Host, Port, Socket, {SSLOptions, SocketOptions, Tracker}, Us
user_data_buffer = <<>>,
session_cache_cb = SessionCacheCb,
renegotiation = {false, first},
+ allow_renegotiate = SSLOptions#ssl_options.client_renegotiation,
start_or_recv_from = undefined,
send_queue = queue:new(),
protocol_cb = ?MODULE,
diff --git a/lib/ssl/test/ssl_basic_SUITE.erl b/lib/ssl/test/ssl_basic_SUITE.erl
index df9432a43b..4d5966fed9 100644
--- a/lib/ssl/test/ssl_basic_SUITE.erl
+++ b/lib/ssl/test/ssl_basic_SUITE.erl
@@ -162,7 +162,8 @@ renegotiate_tests() ->
client_no_wrap_sequence_number,
server_no_wrap_sequence_number,
renegotiate_dos_mitigate_active,
- renegotiate_dos_mitigate_passive].
+ renegotiate_dos_mitigate_passive,
+ renegotiate_dos_mitigate_absolute].
cipher_tests() ->
[cipher_suites,
@@ -2955,8 +2956,36 @@ renegotiate_dos_mitigate_passive(Config) when is_list(Config) ->
ssl_test_lib:close(Client).
%%--------------------------------------------------------------------
+renegotiate_dos_mitigate_absolute() ->
+ [{doc, "Mitigate DOS computational attack by not allowing client to initiate renegotiation"}].
+renegotiate_dos_mitigate_absolute(Config) when is_list(Config) ->
+ ServerOpts = ?config(server_opts, Config),
+ ClientOpts = ?config(client_opts, Config),
+
+ {ClientNode, ServerNode, Hostname} = ssl_test_lib:run_where(Config),
+
+ Server =
+ ssl_test_lib:start_server([{node, ServerNode}, {port, 0},
+ {from, self()},
+ {mfa, {ssl_test_lib, send_recv_result_active, []}},
+ {options, [{client_renegotiation, false} | ServerOpts]}]),
+ Port = ssl_test_lib:inet_port(Server),
+
+ Client = ssl_test_lib:start_client([{node, ClientNode}, {port, Port},
+ {host, Hostname},
+ {from, self()},
+ {mfa, {?MODULE,
+ renegotiate_rejected,
+ []}},
+ {options, ClientOpts}]),
+
+ ssl_test_lib:check_result(Client, ok, Server, ok),
+ ssl_test_lib:close(Server),
+ ssl_test_lib:close(Client).
+
+%%--------------------------------------------------------------------
tcp_error_propagation_in_active_mode() ->
- [{doc,"Test that process recives {ssl_error, Socket, closed} when tcp error ocurres"}].
+ [{doc,"Test that process recives {ssl_error, Socket, closed} when tcp error occurs"}].
tcp_error_propagation_in_active_mode(Config) when is_list(Config) ->
ClientOpts = ?config(client_opts, Config),
ServerOpts = ?config(server_opts, Config),
@@ -3390,12 +3419,12 @@ renegotiate_reuse_session(Socket, Data) ->
renegotiate(Socket, Data).
renegotiate_immediately(Socket) ->
- receive
+ receive
{ssl, Socket, "Hello world"} ->
ok;
%% Handle 1/n-1 splitting countermeasure Rizzo/Duong-Beast
{ssl, Socket, "H"} ->
- receive
+ receive
{ssl, Socket, "ello world"} ->
ok
end
@@ -3407,6 +3436,26 @@ renegotiate_immediately(Socket) ->
ct:log("Renegotiated again"),
ssl:send(Socket, "Hello world"),
ok.
+
+renegotiate_rejected(Socket) ->
+ receive
+ {ssl, Socket, "Hello world"} ->
+ ok;
+ %% Handle 1/n-1 splitting countermeasure Rizzo/Duong-Beast
+ {ssl, Socket, "H"} ->
+ receive
+ {ssl, Socket, "ello world"} ->
+ ok
+ end
+ end,
+ {error, renegotiation_rejected} = ssl:renegotiate(Socket),
+ {error, renegotiation_rejected} = ssl:renegotiate(Socket),
+ ct:sleep(?RENEGOTIATION_DISABLE_TIME +1),
+ {error, renegotiation_rejected} = ssl:renegotiate(Socket),
+ ct:log("Failed to renegotiate again"),
+ ssl:send(Socket, "Hello world"),
+ ok.
+
new_config(PrivDir, ServerOpts0) ->
CaCertFile = proplists:get_value(cacertfile, ServerOpts0),