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-rw-r--r--lib/ssl/src/dtls_connection.erl65
-rw-r--r--lib/ssl/src/ssl_alert.erl4
-rw-r--r--lib/ssl/src/ssl_alert.hrl4
3 files changed, 63 insertions, 10 deletions
diff --git a/lib/ssl/src/dtls_connection.erl b/lib/ssl/src/dtls_connection.erl
index b6aafc3fa4..ff3e69bae5 100644
--- a/lib/ssl/src/dtls_connection.erl
+++ b/lib/ssl/src/dtls_connection.erl
@@ -276,7 +276,9 @@ init({call, _} = Type, Event, #state{role = server, transport_cb = gen_udp} = St
Result = ssl_connection:init(Type, Event,
State#state{flight_state = {retransmit, ?INITIAL_RETRANSMIT_TIMEOUT},
protocol_specific = #{current_cookie_secret => dtls_v1:cookie_secret(),
- previous_cookie_secret => <<>>}},
+ previous_cookie_secret => <<>>,
+ ignored_alerts => 0,
+ max_ignored_alerts => 10}},
?MODULE),
erlang:send_after(dtls_v1:cookie_timeout(), self(), new_cookie_secret),
Result;
@@ -374,7 +376,7 @@ hello(internal, #server_hello{} = Hello,
ssl_options = SslOptions} = State) ->
case dtls_handshake:hello(Hello, SslOptions, ConnectionStates0, Renegotiation) of
#alert{} = Alert ->
- ssl_connection:handle_own_alert(Alert, ReqVersion, hello, State);
+ handle_own_alert(Alert, ReqVersion, hello, State);
{Version, NewId, ConnectionStates, ProtoExt, Protocol} ->
ssl_connection:handle_session(Hello,
Version, NewId, ConnectionStates, ProtoExt, Protocol, State)
@@ -546,7 +548,7 @@ handle_call(Event, From, StateName, State) ->
handle_common_event(internal, #alert{} = Alert, StateName,
#state{negotiated_version = Version} = State) ->
- ssl_connection:handle_own_alert(Alert, Version, StateName, State);
+ handle_own_alert(Alert, Version, StateName, State);
%%% DTLS record protocol level handshake messages
handle_common_event(internal, #ssl_tls{type = ?HANDSHAKE,
fragment = Data},
@@ -565,7 +567,7 @@ handle_common_event(internal, #ssl_tls{type = ?HANDSHAKE,
State#state{unprocessed_handshake_events = unprocessed_events(Events)}, Events}
end
catch throw:#alert{} = Alert ->
- ssl_connection:handle_own_alert(Alert, Version, StateName, State0)
+ handle_own_alert(Alert, Version, StateName, State0)
end;
%%% DTLS record protocol level application data messages
handle_common_event(internal, #ssl_tls{type = ?APPLICATION_DATA, fragment = Data}, StateName, State) ->
@@ -580,7 +582,7 @@ handle_common_event(internal, #ssl_tls{type = ?ALERT, fragment = EncAlerts}, Sta
Alerts = [_|_] ->
handle_alerts(Alerts, {next_state, StateName, State});
#alert{} = Alert ->
- ssl_connection:handle_own_alert(Alert, Version, StateName, State)
+ handle_own_alert(Alert, Version, StateName, State)
end;
%% Ignore unknown TLS record level protocol messages
handle_common_event(internal, #ssl_tls{type = _Unknown}, StateName, State) ->
@@ -632,7 +634,7 @@ handle_client_hello(#client_hello{client_version = ClientVersion} = Hello,
case dtls_handshake:hello(Hello, SslOpts, {Port, Session0, Cache, CacheCb,
ConnectionStates0, Cert, KeyExAlg}, Renegotiation) of
#alert{} = Alert ->
- ssl_connection:handle_own_alert(Alert, ClientVersion, hello, State0);
+ handle_own_alert(Alert, ClientVersion, hello, State0);
{Version, {Type, Session},
ConnectionStates, Protocol0, ServerHelloExt, HashSign} ->
Protocol = case Protocol0 of
@@ -967,3 +969,54 @@ unprocessed_events(Events) ->
%% process more TLS-records received on the socket.
erlang:length(Events)-1.
+handle_own_alert(Alert, Version, StateName, #state{transport_cb = gen_udp,
+ role = Role,
+ ssl_options = Options} = State0) ->
+ case ignore_alert(Alert, State0) of
+ {true, State} ->
+ log_ignore_alert(Options#ssl_options.log_alert, StateName, Alert, Role),
+ {next_state, StateName, State};
+ {false, State} ->
+ ssl_connection:handle_own_alert(Alert, Version, StateName, State)
+ end;
+handle_own_alert(Alert, Version, StateName, State) ->
+ ssl_connection:handle_own_alert(Alert, Version, StateName, State).
+
+
+ignore_alert(#alert{level = ?FATAL}, #state{protocol_specific = #{ignored_alerts := N,
+ max_ignored_alerts := N}} = State) ->
+ {false, State};
+ignore_alert(#alert{level = ?FATAL} = Alert,
+ #state{protocol_specific = #{ignored_alerts := N} = PS} = State) ->
+ case is_ignore_alert(Alert) of
+ true ->
+ {true, State#state{protocol_specific = PS#{ignored_alerts => N+1}}};
+ false ->
+ {false, State}
+ end;
+ignore_alert(_, State) ->
+ {false, State}.
+
+%% RFC 6347 4.1.2.7. Handling Invalid Records
+%% recommends to silently ignore invalid DTLS records when
+%% upd is the transport. Note we do not support compression so no need
+%% include ?DECOMPRESSION_FAILURE
+is_ignore_alert(#alert{description = ?BAD_RECORD_MAC}) ->
+ true;
+is_ignore_alert(#alert{description = ?RECORD_OVERFLOW}) ->
+ true;
+is_ignore_alert(#alert{description = ?DECODE_ERROR}) ->
+ true;
+is_ignore_alert(#alert{description = ?DECRYPT_ERROR}) ->
+ true;
+is_ignore_alert(#alert{description = ?ILLEGAL_PARAMETER}) ->
+ true;
+is_ignore_alert(_) ->
+ false.
+
+log_ignore_alert(true, StateName, Alert, Role) ->
+ Txt = ssl_alert:alert_txt(Alert),
+ error_logger:format("DTLS over UDP ~p: In state ~p ignored to send ALERT ~s as DoS-attack mitigation \n",
+ [Role, StateName, Txt]);
+log_ignore_alert(false, _, _,_) ->
+ ok.
diff --git a/lib/ssl/src/ssl_alert.erl b/lib/ssl/src/ssl_alert.erl
index b923785e17..2749feb1eb 100644
--- a/lib/ssl/src/ssl_alert.erl
+++ b/lib/ssl/src/ssl_alert.erl
@@ -103,8 +103,8 @@ description_txt(?UNEXPECTED_MESSAGE) ->
"Unexpected Message";
description_txt(?BAD_RECORD_MAC) ->
"Bad Record MAC";
-description_txt(?DECRYPTION_FAILED) ->
- "Decryption Failed";
+description_txt(?DECRYPTION_FAILED_RESERVED) ->
+ "Decryption Failed Reserved";
description_txt(?RECORD_OVERFLOW) ->
"Record Overflow";
description_txt(?DECOMPRESSION_FAILURE) ->
diff --git a/lib/ssl/src/ssl_alert.hrl b/lib/ssl/src/ssl_alert.hrl
index 1aabb6c55a..35670edea5 100644
--- a/lib/ssl/src/ssl_alert.hrl
+++ b/lib/ssl/src/ssl_alert.hrl
@@ -40,7 +40,7 @@
%% close_notify(0),
%% unexpected_message(10),
%% bad_record_mac(20),
-%% decryption_failed(21),
+%% decryption_failed_reserved(21),
%% record_overflow(22),
%% decompression_failure(30),
%% handshake_failure(40),
@@ -78,7 +78,7 @@
-define(CLOSE_NOTIFY, 0).
-define(UNEXPECTED_MESSAGE, 10).
-define(BAD_RECORD_MAC, 20).
--define(DECRYPTION_FAILED, 21).
+-define(DECRYPTION_FAILED_RESERVED, 21).
-define(RECORD_OVERFLOW, 22).
-define(DECOMPRESSION_FAILURE, 30).
-define(HANDSHAKE_FAILURE, 40).
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-31 03:22:17 +0000