From a3d68814e1cd1ef062582901e0102f60a323bae5 Mon Sep 17 00:00:00 2001 From: Ingela Anderton Andin Date: Thu, 4 Jan 2018 17:17:50 +0100 Subject: ssl: Add record version sanity check --- lib/ssl/src/dtls_connection.erl | 13 +++++++++--- lib/ssl/src/dtls_record.erl | 30 ++++++++++++++++------------ lib/ssl/src/tls_connection.erl | 26 +++++++++++++++++++----- lib/ssl/src/tls_record.erl | 37 +++++++++++++++++++++++++++-------- lib/ssl/test/ssl_to_openssl_SUITE.erl | 2 +- 5 files changed, 79 insertions(+), 29 deletions(-) diff --git a/lib/ssl/src/dtls_connection.erl b/lib/ssl/src/dtls_connection.erl index 9cb6934dce..03725089dd 100644 --- a/lib/ssl/src/dtls_connection.erl +++ b/lib/ssl/src/dtls_connection.erl @@ -758,10 +758,12 @@ initial_state(Role, Host, Port, Socket, {SSLOptions, SocketOptions, _}, User, flight_state = {retransmit, ?INITIAL_RETRANSMIT_TIMEOUT} }. -next_dtls_record(Data, #state{protocol_buffers = #protocol_buffers{ +next_dtls_record(Data, StateName, #state{protocol_buffers = #protocol_buffers{ dtls_record_buffer = Buf0, dtls_cipher_texts = CT0} = Buffers} = State0) -> - case dtls_record:get_dtls_records(Data, Buf0) of + case dtls_record:get_dtls_records(Data, + acceptable_record_versions(StateName, State0), + Buf0) of {Records, Buf1} -> CT1 = CT0 ++ Records, next_record(State0#state{protocol_buffers = @@ -771,6 +773,11 @@ next_dtls_record(Data, #state{protocol_buffers = #protocol_buffers{ Alert end. +acceptable_record_versions(hello, _) -> + [dtls_record:protocol_version(Vsn) || Vsn <- ?ALL_DATAGRAM_SUPPORTED_VERSIONS]; +acceptable_record_versions(_, #state{negotiated_version = Version}) -> + [Version]. + dtls_handshake_events(Packets) -> lists:map(fun(Packet) -> {next_event, internal, {handshake, Packet}} @@ -828,7 +835,7 @@ handle_client_hello(#client_hello{client_version = ClientVersion} = Hello, %% raw data from socket, unpack records handle_info({Protocol, _, _, _, Data}, StateName, #state{data_tag = Protocol} = State0) -> - case next_dtls_record(Data, State0) of + case next_dtls_record(Data, StateName, State0) of {Record, State} -> next_event(StateName, Record, State); #alert{} = Alert -> diff --git a/lib/ssl/src/dtls_record.erl b/lib/ssl/src/dtls_record.erl index 2dcc6efc91..316de05532 100644 --- a/lib/ssl/src/dtls_record.erl +++ b/lib/ssl/src/dtls_record.erl @@ -30,7 +30,7 @@ -include("ssl_cipher.hrl"). %% Handling of incoming data --export([get_dtls_records/2, init_connection_states/2, empty_connection_state/1]). +-export([get_dtls_records/3, init_connection_states/2, empty_connection_state/1]). -export([save_current_connection_state/2, next_epoch/2, get_connection_state_by_epoch/3, replay_detect/2, init_connection_state_seq/2, current_connection_state_epoch/2]). @@ -163,17 +163,25 @@ current_connection_state_epoch(#{current_write := #{epoch := Epoch}}, Epoch. %%-------------------------------------------------------------------- --spec get_dtls_records(binary(), binary()) -> {[binary()], binary()} | #alert{}. +-spec get_dtls_records(binary(), [dtls_version()], binary()) -> {[binary()], binary()} | #alert{}. %% %% Description: Given old buffer and new data from UDP/SCTP, packs up a records %% and returns it as a list of tls_compressed binaries also returns leftover %% data %%-------------------------------------------------------------------- -get_dtls_records(Data, <<>>) -> - get_dtls_records_aux(Data, []); -get_dtls_records(Data, Buffer) -> - get_dtls_records_aux(list_to_binary([Buffer, Data]), []). - +get_dtls_records(Data, Versions, Buffer) -> + BinData = list_to_binary([Buffer, Data]), + case erlang:byte_size(BinData) of + N when N >= 3 -> + case assert_version(BinData, Versions) of + true -> + get_dtls_records_aux(BinData, []); + false -> + ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC) + end; + _ -> + get_dtls_records_aux(BinData, []) + end. %%==================================================================== %% Encoding DTLS records @@ -397,6 +405,8 @@ initial_connection_state(ConnectionEnd, BeastMitigation) -> client_verify_data => undefined, server_verify_data => undefined }. +assert_version(<>, Versions) -> + is_acceptable_version({MajVer, MinVer}, Versions). get_dtls_records_aux(<>, _Acc) when Length > ?MAX_CIPHER_TEXT_LENGTH -> ?ALERT_REC(?FATAL, ?RECORD_OVERFLOW); -get_dtls_records_aux(<<1:1, Length0:15, _/binary>>,_Acc) - when Length0 > ?MAX_CIPHER_TEXT_LENGTH -> - ?ALERT_REC(?FATAL, ?RECORD_OVERFLOW); - get_dtls_records_aux(Data, Acc) -> case size(Data) =< ?MAX_CIPHER_TEXT_LENGTH + ?INITIAL_BYTES of true -> diff --git a/lib/ssl/src/tls_connection.erl b/lib/ssl/src/tls_connection.erl index 39f3ed996e..914ee9f22f 100644 --- a/lib/ssl/src/tls_connection.erl +++ b/lib/ssl/src/tls_connection.erl @@ -629,18 +629,34 @@ initial_state(Role, Host, Port, Socket, {SSLOptions, SocketOptions, Tracker}, Us flight_buffer = [] }. -next_tls_record(Data, #state{protocol_buffers = #protocol_buffers{tls_record_buffer = Buf0, - tls_cipher_texts = CT0} = Buffers} = State0) -> - case tls_record:get_tls_records(Data, Buf0) of +next_tls_record(Data, StateName, #state{protocol_buffers = + #protocol_buffers{tls_record_buffer = Buf0, + tls_cipher_texts = CT0} = Buffers} + = State0) -> + case tls_record:get_tls_records(Data, + acceptable_record_versions(StateName, State0), + Buf0) of {Records, Buf1} -> CT1 = CT0 ++ Records, next_record(State0#state{protocol_buffers = Buffers#protocol_buffers{tls_record_buffer = Buf1, tls_cipher_texts = CT1}}); #alert{} = Alert -> - Alert + handle_record_alert(Alert, State0) end. +acceptable_record_versions(hello, #state{ssl_options = #ssl_options{v2_hello_compatible = true}}) -> + [tls_record:protocol_version(Vsn) || Vsn <- ?ALL_AVAILABLE_VERSIONS ++ ['sslv2']]; +acceptable_record_versions(hello, _) -> + [tls_record:protocol_version(Vsn) || Vsn <- ?ALL_AVAILABLE_VERSIONS]; +acceptable_record_versions(_, #state{negotiated_version = Version}) -> + [Version]. +handle_record_alert(#alert{description = ?BAD_RECORD_MAC}, + #state{ssl_options = #ssl_options{v2_hello_compatible = true}}) -> + ?ALERT_REC(?FATAL, ?PROTOCOL_VERSION); +handle_record_alert(Alert, _) -> + Alert. + tls_handshake_events(Packets) -> lists:map(fun(Packet) -> {next_event, internal, {handshake, Packet}} @@ -649,7 +665,7 @@ tls_handshake_events(Packets) -> %% raw data from socket, upack records handle_info({Protocol, _, Data}, StateName, #state{data_tag = Protocol} = State0) -> - case next_tls_record(Data, State0) of + case next_tls_record(Data, StateName, State0) of {Record, State} -> next_event(StateName, Record, State); #alert{} = Alert -> diff --git a/lib/ssl/src/tls_record.erl b/lib/ssl/src/tls_record.erl index ab179c1bf0..188ec6809d 100644 --- a/lib/ssl/src/tls_record.erl +++ b/lib/ssl/src/tls_record.erl @@ -32,7 +32,7 @@ -include("ssl_cipher.hrl"). %% Handling of incoming data --export([get_tls_records/2, init_connection_states/2]). +-export([get_tls_records/3, init_connection_states/2]). %% Encoding TLS records -export([encode_handshake/3, encode_alert_record/3, @@ -75,16 +75,25 @@ init_connection_states(Role, BeastMitigation) -> pending_write => Pending}. %%-------------------------------------------------------------------- --spec get_tls_records(binary(), binary()) -> {[binary()], binary()} | #alert{}. +-spec get_tls_records(binary(), [tls_version()], binary()) -> {[binary()], binary()} | #alert{}. %% %% and returns it as a list of tls_compressed binaries also returns leftover %% Description: Given old buffer and new data from TCP, packs up a records %% data %%-------------------------------------------------------------------- -get_tls_records(Data, <<>>) -> - get_tls_records_aux(Data, []); -get_tls_records(Data, Buffer) -> - get_tls_records_aux(list_to_binary([Buffer, Data]), []). +get_tls_records(Data, Versions, Buffer) -> + BinData = list_to_binary([Buffer, Data]), + case erlang:byte_size(BinData) of + N when N >= 3 -> + case assert_version(BinData, Versions) of + true -> + get_tls_records_aux(BinData, []); + false -> + ?ALERT_REC(?FATAL, ?BAD_RECORD_MAC) + end; + _ -> + get_tls_records_aux(BinData, []) + end. %%==================================================================== %% Encoding @@ -385,6 +394,19 @@ initial_connection_state(ConnectionEnd, BeastMitigation) -> server_verify_data => undefined }. +assert_version(<<1:1, Length0:15, Data0:Length0/binary, _/binary>>, Versions) -> + case Data0 of + <> -> + %% First check v2_hello_compatible mode is active + lists:member({2,0}, Versions) andalso + %% andalso we want to negotiate higher version + lists:member({Major, Minor}, Versions -- [{2,0}]); + _ -> + false + end; +assert_version(<>, Versions) -> + is_acceptable_version({MajVer, MinVer}, Versions). + get_tls_records_aux(<>, Acc) -> @@ -428,10 +450,9 @@ get_tls_records_aux(<<1:1, Length0:15, Data0:Length0/binary, Rest/binary>>, end; get_tls_records_aux(<<0:1, _CT:7, ?BYTE(_MajVer), ?BYTE(_MinVer), - ?UINT16(Length), _/binary>>, + ?UINT16(Length), _/binary>>, _Acc) when Length > ?MAX_CIPHER_TEXT_LENGTH -> ?ALERT_REC(?FATAL, ?RECORD_OVERFLOW); - get_tls_records_aux(<<1:1, Length0:15, _/binary>>,_Acc) when Length0 > ?MAX_CIPHER_TEXT_LENGTH -> ?ALERT_REC(?FATAL, ?RECORD_OVERFLOW); diff --git a/lib/ssl/test/ssl_to_openssl_SUITE.erl b/lib/ssl/test/ssl_to_openssl_SUITE.erl index bbb925e742..33cdc325f4 100644 --- a/lib/ssl/test/ssl_to_openssl_SUITE.erl +++ b/lib/ssl/test/ssl_to_openssl_SUITE.erl @@ -1016,7 +1016,7 @@ ssl2_erlang_server_openssl_client(Config) when is_list(Config) -> ct:log("Ports ~p~n", [[erlang:port_info(P) || P <- erlang:ports()]]), consume_port_exit(OpenSslPort), - ssl_test_lib:check_result(Server, {error, {tls_alert, "handshake failure"}}), + ssl_test_lib:check_result(Server, {error, {tls_alert, "bad record mac"}}), process_flag(trap_exit, false). %%-------------------------------------------------------------------- ssl2_erlang_server_openssl_client_comp() -> -- cgit v1.2.3