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-rw-r--r--lib/ssl/src/ssl_handshake.erl17
-rw-r--r--lib/ssl/src/tls_handshake.erl114
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, <<>>};