From 73b526ce765dc7ac71fdae349da44941d8201d9c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C3=A9ter=20Dimitrov?= Date: Wed, 24 Jul 2019 11:11:07 +0200 Subject: ssl: Implement option honor_cipher_order in TLS 1.3 --- lib/ssl/src/tls_handshake_1_3.erl | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'lib/ssl/src') diff --git a/lib/ssl/src/tls_handshake_1_3.erl b/lib/ssl/src/tls_handshake_1_3.erl index 6aeb9f5663..c29366e717 100644 --- a/lib/ssl/src/tls_handshake_1_3.erl +++ b/lib/ssl/src/tls_handshake_1_3.erl @@ -504,7 +504,8 @@ do_start(#client_hello{cipher_suites = ClientCiphers, ssl_options = #ssl_options{ciphers = ServerCiphers, signature_algs = ServerSignAlgs, supported_groups = ServerGroups0, - alpn_preferred_protocols = ALPNPreferredProtocols}, + alpn_preferred_protocols = ALPNPreferredProtocols, + honor_cipher_order = HonorCipherOrder}, session = #session{own_certificate = Cert}} = State0) -> ClientGroups0 = maps:get(elliptic_curves, Extensions, undefined), ClientGroups = get_supported_groups(ClientGroups0), @@ -531,7 +532,7 @@ do_start(#client_hello{cipher_suites = ClientCiphers, %% cipher suite, an (EC)DHE group and key share for key establishment, %% and a signature algorithm/certificate pair to authenticate itself to %% the client. - Cipher = Maybe(select_cipher_suite(ClientCiphers, ServerCiphers)), + Cipher = Maybe(select_cipher_suite(HonorCipherOrder, ClientCiphers, ServerCiphers)), Groups = Maybe(select_common_groups(ServerGroups, ClientGroups)), Maybe(validate_client_key_share(ClientGroups, ClientShares)), @@ -1731,15 +1732,19 @@ handle_alpn([ServerProtocol|T], ClientProtocols) -> end. -select_cipher_suite([], _) -> +select_cipher_suite(_, [], _) -> {error, no_suitable_cipher}; -select_cipher_suite([Cipher|ClientCiphers], ServerCiphers) -> +%% If honor_cipher_order is set to true, use the server's preference for +%% cipher suite selection. +select_cipher_suite(true, ClientCiphers, ServerCiphers) -> + select_cipher_suite(false, ServerCiphers, ClientCiphers); +select_cipher_suite(false, [Cipher|ClientCiphers], ServerCiphers) -> case lists:member(Cipher, tls_v1:suites('TLS_v1.3')) andalso lists:member(Cipher, ServerCiphers) of true -> {ok, Cipher}; false -> - select_cipher_suite(ClientCiphers, ServerCiphers) + select_cipher_suite(false, ClientCiphers, ServerCiphers) end. -- cgit v1.2.3