diff options
| -rw-r--r-- | lib/ssl/src/ssl_handshake.erl | 17 | ||||
| -rw-r--r-- | lib/ssl/src/tls_handshake.erl | 114 |
2 files changed, 117 insertions, 14 deletions
diff --git a/lib/ssl/src/ssl_handshake.erl b/lib/ssl/src/ssl_handshake.erl index e9f482d6d8..98e9d9da7e 100644 --- a/lib/ssl/src/ssl_handshake.erl +++ b/lib/ssl/src/ssl_handshake.erl @@ -53,7 +53,7 @@ -export([certify/7, certificate_verify/6, verify_signature/5, master_secret/4, server_key_exchange_hash/2, verify_connection/6, init_handshake_history/0, update_handshake_history/2, verify_server_key/5, - select_version/3, extension_value/1 + select_version/3, select_supported_version/2, extension_value/1 ]). %% Encode @@ -505,6 +505,21 @@ verify_server_key(#server_key_params{params_bin = EncParams, select_version(RecordCB, ClientVersion, Versions) -> do_select_version(RecordCB, ClientVersion, Versions). + +%% Called by TLS 1.2/1.3 Server when "supported_versions" is present +%% in ClientHello. +%% Input lists are ordered (highest first) +select_supported_version([], _ServerVersions) -> + undefined; +select_supported_version([ClientVersion|T], ServerVersions) -> + case lists:member(ClientVersion, ServerVersions) of + true -> + ClientVersion; + false -> + select_supported_version(T, ServerVersions) + end. + + %%==================================================================== %% Encode handshake %%==================================================================== diff --git a/lib/ssl/src/tls_handshake.erl b/lib/ssl/src/tls_handshake.erl index 4e6bbb5061..39f0c1680b 100644 --- a/lib/ssl/src/tls_handshake.erl +++ b/lib/ssl/src/tls_handshake.erl @@ -61,6 +61,18 @@ client_hello(Host, Port, ConnectionStates, } = SslOpts, Cache, CacheCb, Renegotiation, OwnCert) -> Version = tls_record:highest_protocol_version(Versions), + + %% In TLS 1.3, the client indicates its version preferences in the + %% "supported_versions" extension (Section 4.2.1) and the + %% legacy_version field MUST be set to 0x0303, which is the version + %% number for TLS 1.2. + LegacyVersion = + case tls_record:is_higher(Version, {3,2}) of + true -> + {3,3}; + false -> + Version + end, #{security_parameters := SecParams} = ssl_record:pending_connection_state(ConnectionStates, read), AvailableCipherSuites = ssl_handshake:available_suites(UserSuites, Version), @@ -71,7 +83,7 @@ client_hello(Host, Port, ConnectionStates, CipherSuites = ssl_handshake:cipher_suites(AvailableCipherSuites, Renegotiation, Fallback), Id = ssl_session:client_id({Host, Port, SslOpts}, Cache, CacheCb, OwnCert), #client_hello{session_id = Id, - client_version = Version, + client_version = LegacyVersion, cipher_suites = CipherSuites, compression_methods = ssl_record:compressions(), random = SecParams#security_parameters.client_random, @@ -93,6 +105,37 @@ client_hello(Host, Port, ConnectionStates, %% %% Description: Handles a received hello message %%-------------------------------------------------------------------- + +%% TLS 1.3 - 4.2.1. Supported Versions +%% If the "supported_versions" extension in the ServerHello contains a +%% version not offered by the client or contains a version prior to TLS +%% 1.3, the client MUST abort the handshake with an "illegal_parameter" +%% alert. +%%-------------------------------------------------------------------- +%% TLS 1.2 Client +%% +%% - If "supported_version" is present (ServerHello): +%% - Abort handshake with an "illegal_parameter" alert +hello(#server_hello{server_version = Version, + extensions = #hello_extensions{ + server_hello_selected_version = + #server_hello_selected_version{selected_version = Version} + }}, + #ssl_options{versions = SupportedVersions}, + _ConnectionStates0, _Renegotiation) -> + case tls_record:is_higher({3,4}, Version) of + true -> + ?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER); + false -> + case tls_record:is_acceptable_version(Version, SupportedVersions) of + true -> + %% Implement TLS 1.3 statem ??? + ?ALERT_REC(?FATAL, ?PROTOCOL_VERSION); + false -> + ?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER) + end + end; + hello(#server_hello{server_version = Version, random = Random, cipher_suite = CipherSuite, compression_method = Compression, @@ -107,6 +150,37 @@ hello(#server_hello{server_version = Version, random = Random, false -> ?ALERT_REC(?FATAL, ?PROTOCOL_VERSION) end; + + +%% TLS 1.2 Server +%% - If "supported_versions" is present (ClientHello): +%% - Select version from "supported_versions" (ignore ClientHello.legacy_version) +%% - If server only supports versions greater than "supported_versions": +%% - Abort handshake with a "protocol_version" alert (*) +%% - If "supported_versions" is absent (ClientHello): +%% - Negotiate the minimum of ClientHello.legacy_version and TLS 1.2 (**) +%% - If server only supports versions greater than ClientHello.legacy_version: +%% - Abort handshake with a "protocol_version" alert +%% +%% (*) Sends alert even if there is a gap in supported versions +%% e.g. Server 1.0,1.2 Client 1.1,1.3 +%% (**) Current implementation can negotiate a version not supported by the client +%% e.g. Server 1.0,1.2 Client 1.1 -> ServerHello 1.0 +hello(#client_hello{client_version = _ClientVersion, + cipher_suites = CipherSuites, + extensions = #hello_extensions{ + client_hello_versions = + #client_hello_versions{versions = ClientVersions} + }} = Hello, + #ssl_options{versions = Versions} = SslOpts, + Info, Renegotiation) -> + try + Version = ssl_handshake:select_supported_version(ClientVersions, Versions), + do_hello(Version, Versions, CipherSuites, Hello, SslOpts, Info, Renegotiation) + catch + _:_ -> + ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, malformed_handshake_data) + end; hello(#client_hello{client_version = ClientVersion, cipher_suites = CipherSuites} = Hello, @@ -114,18 +188,7 @@ hello(#client_hello{client_version = ClientVersion, Info, Renegotiation) -> try Version = ssl_handshake:select_version(tls_record, ClientVersion, Versions), - case ssl_cipher:is_fallback(CipherSuites) of - true -> - Highest = tls_record:highest_protocol_version(Versions), - case tls_record:is_higher(Highest, Version) of - true -> - ?ALERT_REC(?FATAL, ?INAPPROPRIATE_FALLBACK); - false -> - handle_client_hello(Version, Hello, SslOpts, Info, Renegotiation) - end; - false -> - handle_client_hello(Version, Hello, SslOpts, Info, Renegotiation) - end + do_hello(Version, Versions, CipherSuites, Hello, SslOpts, Info, Renegotiation) catch _:_ -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, malformed_handshake_data) @@ -242,6 +305,31 @@ handle_server_hello_extensions(Version, SessionId, Random, CipherSuite, {ConnectionStates, ProtoExt, Protocol} -> {Version, SessionId, ConnectionStates, ProtoExt, Protocol} end. + + +do_hello(undefined, _Versions, _CipherSuites, _Hello, _SslOpts, _Info, _Renegotiation) -> + ?ALERT_REC(?FATAL, ?PROTOCOL_VERSION); +do_hello(Version, Versions, CipherSuites, Hello, SslOpts, Info, Renegotiation) -> + case tls_record:is_higher({3,4}, Version) of + true -> %% TLS 1.2 and older + case ssl_cipher:is_fallback(CipherSuites) of + true -> + Highest = tls_record:highest_protocol_version(Versions), + case tls_record:is_higher(Highest, Version) of + true -> + ?ALERT_REC(?FATAL, ?INAPPROPRIATE_FALLBACK); + false -> + handle_client_hello(Version, Hello, SslOpts, Info, Renegotiation) + end; + false -> + handle_client_hello(Version, Hello, SslOpts, Info, Renegotiation) + end; + false -> + %% Implement TLS 1.3 statem ??? + ?ALERT_REC(?FATAL, ?PROTOCOL_VERSION) + end. + + %%-------------------------------------------------------------------- enc_handshake(#hello_request{}, _Version) -> {?HELLO_REQUEST, <<>>}; |