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-rw-r--r--lib/ssl/doc/src/ssl.xml8
-rw-r--r--lib/ssl/src/ssl.erl8
-rw-r--r--lib/ssl/src/ssl_handshake.hrl3
-rw-r--r--lib/ssl/src/ssl_internal.hrl3
-rw-r--r--lib/ssl/src/tls_connection.erl50
-rw-r--r--lib/ssl/test/ssl_basic_SUITE.erl26
6 files changed, 83 insertions, 15 deletions
diff --git a/lib/ssl/doc/src/ssl.xml b/lib/ssl/doc/src/ssl.xml
index edc7e0d8b2..916b41742e 100644
--- a/lib/ssl/doc/src/ssl.xml
+++ b/lib/ssl/doc/src/ssl.xml
@@ -424,6 +424,14 @@ marker="public_key:public_key#pkix_path_validation-3">public_key:pkix_path_valid
</taglist>
</item>
+
+ <tag><c>max_handshake_size</c></tag>
+ <item>
+ <p>Integer (24 bits unsigned). Used to limit the size of
+ valid TLS handshake packets to avoid DoS attacks.
+ Defaults to 256*1024.</p>
+ </item>
+
</taglist>
</item>
diff --git a/lib/ssl/src/ssl.erl b/lib/ssl/src/ssl.erl
index c72ee44a95..0b7229b67e 100644
--- a/lib/ssl/src/ssl.erl
+++ b/lib/ssl/src/ssl.erl
@@ -765,7 +765,8 @@ handle_options(Opts0, Role) ->
client, Role),
crl_check = handle_option(crl_check, Opts, false),
crl_cache = handle_option(crl_cache, Opts, {ssl_crl_cache, {internal, []}}),
- v2_hello_compatible = handle_option(v2_hello_compatible, Opts, false)
+ v2_hello_compatible = handle_option(v2_hello_compatible, Opts, false),
+ max_handshake_size = handle_option(max_handshake_size, Opts, ?DEFAULT_MAX_HANDSHAKE_SIZE)
},
CbInfo = proplists:get_value(cb_info, Opts, default_cb_info(Protocol)),
@@ -780,7 +781,8 @@ handle_options(Opts0, Role) ->
alpn_preferred_protocols, next_protocols_advertised,
client_preferred_next_protocols, log_alert,
server_name_indication, honor_cipher_order, padding_check, crl_check, crl_cache,
- fallback, signature_algs, eccs, honor_ecc_order, beast_mitigation, v2_hello_compatible],
+ fallback, signature_algs, eccs, honor_ecc_order, beast_mitigation, v2_hello_compatible,
+ max_handshake_size],
SockOpts = lists:foldl(fun(Key, PropList) ->
proplists:delete(Key, PropList)
@@ -1028,6 +1030,8 @@ validate_option(beast_mitigation, Value) when Value == one_n_minus_one orelse
Value;
validate_option(v2_hello_compatible, Value) when is_boolean(Value) ->
Value;
+validate_option(max_handshake_size, Value) when is_integer(Value) andalso Value =< ?MAX_UNIT24 ->
+ Value;
validate_option(Opt, Value) ->
throw({error, {options, {Opt, Value}}}).
diff --git a/lib/ssl/src/ssl_handshake.hrl b/lib/ssl/src/ssl_handshake.hrl
index fde92035a2..324b7dbde3 100644
--- a/lib/ssl/src/ssl_handshake.hrl
+++ b/lib/ssl/src/ssl_handshake.hrl
@@ -80,6 +80,9 @@
-define(CLIENT_KEY_EXCHANGE, 16).
-define(FINISHED, 20).
+-define(MAX_UNIT24, 8388607).
+-define(DEFAULT_MAX_HANDSHAKE_SIZE, (256*1024)).
+
-record(random, {
gmt_unix_time, % uint32
random_bytes % opaque random_bytes[28]
diff --git a/lib/ssl/src/ssl_internal.hrl b/lib/ssl/src/ssl_internal.hrl
index 98b89bb811..c34af9f82c 100644
--- a/lib/ssl/src/ssl_internal.hrl
+++ b/lib/ssl/src/ssl_internal.hrl
@@ -142,7 +142,8 @@
signature_algs,
eccs,
honor_ecc_order :: boolean(),
- v2_hello_compatible :: boolean()
+ v2_hello_compatible :: boolean(),
+ max_handshake_size :: integer()
}).
-record(socket_options,
diff --git a/lib/ssl/src/tls_connection.erl b/lib/ssl/src/tls_connection.erl
index 32991d3079..77606911be 100644
--- a/lib/ssl/src/tls_connection.erl
+++ b/lib/ssl/src/tls_connection.erl
@@ -424,18 +424,26 @@ handle_common_event(internal, #ssl_tls{type = ?HANDSHAKE, fragment = Data},
ssl_options = Options} = State0) ->
try
{Packets, Buf} = tls_handshake:get_tls_handshake(Version,Data,Buf0, Options),
- State =
+ State1 =
State0#state{protocol_buffers =
Buffers#protocol_buffers{tls_handshake_buffer = Buf}},
- Events = tls_handshake_events(Packets),
- case StateName of
- connection ->
- ssl_connection:hibernate_after(StateName, State, Events);
- _ ->
- {next_state, StateName, State#state{unprocessed_handshake_events = unprocessed_events(Events)}, Events}
- end
+ case Packets of
+ [] ->
+ assert_buffer_sanity(Buf, Options),
+ {Record, State} = next_record(State1),
+ next_event(StateName, Record, State);
+ _ ->
+ Events = tls_handshake_events(Packets),
+ case StateName of
+ connection ->
+ ssl_connection:hibernate_after(StateName, State1, Events);
+ _ ->
+ {next_state, StateName,
+ State1#state{unprocessed_handshake_events = unprocessed_events(Events)}, Events}
+ end
+ end
catch throw:#alert{} = Alert ->
- ssl_connection:handle_own_alert(Alert, Version, StateName, State0)
+ ssl_connection:handle_own_alert(Alert, Version, StateName, State0)
end;
%%% TLS record protocol level application data messages
handle_common_event(internal, #ssl_tls{type = ?APPLICATION_DATA, fragment = Data}, StateName, State) ->
@@ -615,8 +623,6 @@ next_event(StateName, Record, State, Actions) ->
{next_state, StateName, State, [{next_event, internal, Alert} | Actions]}
end.
-tls_handshake_events([]) ->
- throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, malformed_handshake));
tls_handshake_events(Packets) ->
lists:map(fun(Packet) ->
{next_event, internal, {handshake, Packet}}
@@ -735,3 +741,25 @@ unprocessed_events(Events) ->
%% handshake events left to process before we should
%% process more TLS-records received on the socket.
erlang:length(Events)-1.
+
+
+assert_buffer_sanity(<<?BYTE(_Type), ?UINT24(Length), Rest/binary>>, #ssl_options{max_handshake_size = Max}) when
+ Length =< Max ->
+ case size(Rest) of
+ N when N < Length ->
+ true;
+ N when N > Length ->
+ throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE,
+ too_big_handshake_data));
+ _ ->
+ throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE,
+ malformed_handshake_data))
+ end;
+assert_buffer_sanity(Bin, _) ->
+ case size(Bin) of
+ N when N < 3 ->
+ true;
+ _ ->
+ throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE,
+ malformed_handshake_data))
+ end.
diff --git a/lib/ssl/test/ssl_basic_SUITE.erl b/lib/ssl/test/ssl_basic_SUITE.erl
index 52c1af5b4c..de5895d7ba 100644
--- a/lib/ssl/test/ssl_basic_SUITE.erl
+++ b/lib/ssl/test/ssl_basic_SUITE.erl
@@ -136,7 +136,8 @@ options_tests() ->
honor_server_cipher_order,
honor_client_cipher_order,
unordered_protocol_versions_server,
- unordered_protocol_versions_client
+ unordered_protocol_versions_client,
+ max_handshake_size
].
options_tests_tls() ->
@@ -3860,6 +3861,29 @@ unordered_protocol_versions_client(Config) when is_list(Config) ->
ssl_test_lib:check_result(Server, ServerMsg, Client, ClientMsg).
%%--------------------------------------------------------------------
+max_handshake_size() ->
+ [{doc,"Test that we can set max_handshake_size to max value."}].
+
+max_handshake_size(Config) when is_list(Config) ->
+ ClientOpts = ssl_test_lib:ssl_options(client_opts, Config),
+ ServerOpts = ssl_test_lib:ssl_options(server_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, [{max_handshake_size, 8388607} |ServerOpts]}]),
+ Port = ssl_test_lib:inet_port(Server),
+
+ Client = ssl_test_lib:start_client([{node, ClientNode}, {port, Port},
+ {host, Hostname},
+ {from, self()},
+ {mfa, {ssl_test_lib, send_recv_result_active, []}},
+ {options, [{max_handshake_size, 8388607} | ClientOpts]}]),
+
+ ssl_test_lib:check_result(Server, ok, Client, ok).
+
+%%--------------------------------------------------------------------
server_name_indication_option() ->
[{doc,"Test API server_name_indication option to connect."}].
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-11 13:47:23 +0000