%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 2013-2017. All Rights Reserved. %% %% Licensed under the Apache License, Version 2.0 (the "License"); %% you may not use this file except in compliance with the License. %% You may obtain a copy of the License at %% %% http://www.apache.org/licenses/LICENSE-2.0 %% %% Unless required by applicable law or agreed to in writing, software %% distributed under the License is distributed on an "AS IS" BASIS, %% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. %% See the License for the specific language governing permissions and %% limitations under the License. %% %% %CopyrightEnd% %---------------------------------------------------------------------- %% Purpose: Help funtions for handling the SSL-handshake protocol (common %% to SSL/TLS and DTLS %%---------------------------------------------------------------------- -module(ssl_handshake). -include("ssl_handshake.hrl"). -include("ssl_record.hrl"). -include("ssl_cipher.hrl"). -include("ssl_alert.hrl"). -include("ssl_internal.hrl"). -include("ssl_srp.hrl"). -include_lib("public_key/include/public_key.hrl"). -export_type([ssl_handshake/0, ssl_handshake_history/0, public_key_info/0, oid/0]). -type oid() :: tuple(). -type public_key_params() :: #'Dss-Parms'{} | {namedCurve, oid()} | #'ECParameters'{} | term(). -type public_key_info() :: {oid(), #'RSAPublicKey'{} | integer() | #'ECPoint'{}, public_key_params()}. -type ssl_handshake_history() :: {[binary()], [binary()]}. -type ssl_handshake() :: #server_hello{} | #server_hello_done{} | #certificate{} | #certificate_request{} | #client_key_exchange{} | #finished{} | #certificate_verify{} | #hello_request{} | #next_protocol{}. %% Handshake messages -export([hello_request/0, server_hello/4, server_hello_done/0, certificate/4, certificate_request/5, key_exchange/3, finished/5, next_protocol/1]). %% Handle handshake messages -export([certify/7, client_certificate_verify/6, certificate_verify/6, verify_signature/5, master_secret/4, server_key_exchange_hash/2, verify_connection/6, init_handshake_history/0, update_handshake_history/3, verify_server_key/5 ]). %% Encode/Decode -export([encode_handshake/2, encode_hello_extensions/1, encode_client_protocol_negotiation/2, encode_protocols_advertised_on_server/1, decode_handshake/3, decode_hello_extensions/1, decode_server_key/3, decode_client_key/3, decode_suites/2 ]). %% Cipher suites handling -export([available_suites/2, available_signature_algs/2, cipher_suites/2, select_session/11, supported_ecc/1, available_signature_algs/4]). %% Extensions handling -export([client_hello_extensions/5, handle_client_hello_extensions/9, %% Returns server hello extensions handle_server_hello_extensions/9, select_curve/2, select_curve/3 ]). %% MISC -export([select_version/3, prf/6, select_hashsign/4, select_hashsign/5, select_hashsign_algs/3, premaster_secret/2, premaster_secret/3, premaster_secret/4]). %%==================================================================== %% Internal application API %%==================================================================== %% ---------- Create handshake messages ---------- %%-------------------------------------------------------------------- -spec hello_request() -> #hello_request{}. %% %% Description: Creates a hello request message sent by server to %% trigger renegotiation. %%-------------------------------------------------------------------- hello_request() -> #hello_request{}. %%-------------------------------------------------------------------- -spec server_hello(#session{}, ssl_record:ssl_version(), ssl_record:connection_states(), #hello_extensions{}) -> #server_hello{}. %% %% Description: Creates a server hello message. %%-------------------------------------------------------------------- server_hello(SessionId, Version, ConnectionStates, Extensions) -> #{security_parameters := SecParams} = ssl_record:pending_connection_state(ConnectionStates, read), #server_hello{server_version = Version, cipher_suite = SecParams#security_parameters.cipher_suite, compression_method = SecParams#security_parameters.compression_algorithm, random = SecParams#security_parameters.server_random, session_id = SessionId, extensions = Extensions }. %%-------------------------------------------------------------------- -spec server_hello_done() -> #server_hello_done{}. %% %% Description: Creates a server hello done message. %%-------------------------------------------------------------------- server_hello_done() -> #server_hello_done{}. client_hello_extensions(Version, CipherSuites, #ssl_options{signature_algs = SupportedHashSigns, eccs = SupportedECCs} = SslOpts, ConnectionStates, Renegotiation) -> {EcPointFormats, EllipticCurves} = case advertises_ec_ciphers(lists:map(fun ssl_cipher:suite_definition/1, CipherSuites)) of true -> client_ecc_extensions(SupportedECCs); false -> {undefined, undefined} end, SRP = srp_user(SslOpts), #hello_extensions{ renegotiation_info = renegotiation_info(tls_record, client, ConnectionStates, Renegotiation), srp = SRP, signature_algs = available_signature_algs(SupportedHashSigns, Version), ec_point_formats = EcPointFormats, elliptic_curves = EllipticCurves, alpn = encode_alpn(SslOpts#ssl_options.alpn_advertised_protocols, Renegotiation), next_protocol_negotiation = encode_client_protocol_negotiation(SslOpts#ssl_options.next_protocol_selector, Renegotiation), sni = sni(SslOpts#ssl_options.server_name_indication)}. %%-------------------------------------------------------------------- -spec certificate(der_cert(), db_handle(), certdb_ref(), client | server) -> #certificate{} | #alert{}. %% %% Description: Creates a certificate message. %%-------------------------------------------------------------------- certificate(OwnCert, CertDbHandle, CertDbRef, client) -> Chain = case ssl_certificate:certificate_chain(OwnCert, CertDbHandle, CertDbRef) of {ok, _, CertChain} -> CertChain; {error, _} -> %% If no suitable certificate is available, the client %% SHOULD send a certificate message containing no %% certificates. (chapter 7.4.6. RFC 4346) [] end, #certificate{asn1_certificates = Chain}; certificate(OwnCert, CertDbHandle, CertDbRef, server) -> case ssl_certificate:certificate_chain(OwnCert, CertDbHandle, CertDbRef) of {ok, _, Chain} -> #certificate{asn1_certificates = Chain}; {error, _} -> ?ALERT_REC(?FATAL, ?INTERNAL_ERROR, server_has_no_suitable_certificates) end. %%-------------------------------------------------------------------- -spec next_protocol(binary()) -> #next_protocol{}. %% %% Description: Creates a next protocol message %%------------------------------------------------------------------- next_protocol(SelectedProtocol) -> #next_protocol{selected_protocol = SelectedProtocol}. %%-------------------------------------------------------------------- -spec client_certificate_verify(undefined | der_cert(), binary(), ssl_record:ssl_version(), term(), public_key:private_key(), ssl_handshake_history()) -> #certificate_verify{} | ignore | #alert{}. %% %% Description: Creates a certificate_verify message, called by the client. %%-------------------------------------------------------------------- client_certificate_verify(undefined, _, _, _, _, _) -> ignore; client_certificate_verify(_, _, _, _, undefined, _) -> ignore; client_certificate_verify(OwnCert, MasterSecret, Version, {HashAlgo, SignAlgo}, PrivateKey, {Handshake, _}) -> case public_key:pkix_is_fixed_dh_cert(OwnCert) of true -> ?ALERT_REC(?FATAL, ?UNSUPPORTED_CERTIFICATE, fixed_diffie_hellman_prohibited); false -> Hashes = calc_certificate_verify(Version, HashAlgo, MasterSecret, Handshake), Signed = digitally_signed(Version, Hashes, HashAlgo, PrivateKey), #certificate_verify{signature = Signed, hashsign_algorithm = {HashAlgo, SignAlgo}} end. %%-------------------------------------------------------------------- -spec certificate_request(ssl_cipher:cipher_suite(), db_handle(), certdb_ref(), #hash_sign_algos{}, ssl_record:ssl_version()) -> #certificate_request{}. %% %% Description: Creates a certificate_request message, called by the server. %%-------------------------------------------------------------------- certificate_request(CipherSuite, CertDbHandle, CertDbRef, HashSigns, Version) -> Types = certificate_types(ssl_cipher:suite_definition(CipherSuite), Version), Authorities = certificate_authorities(CertDbHandle, CertDbRef), #certificate_request{ certificate_types = Types, hashsign_algorithms = HashSigns, certificate_authorities = Authorities }. %%-------------------------------------------------------------------- -spec key_exchange(client | server, ssl_record:ssl_version(), {premaster_secret, binary(), public_key_info()} | {dh, binary()} | {dh, {binary(), binary()}, #'DHParameter'{}, {HashAlgo::atom(), SignAlgo::atom()}, binary(), binary(), public_key:private_key()} | {ecdh, #'ECPrivateKey'{}} | {psk, binary()} | {dhe_psk, binary(), binary()} | {srp, {binary(), binary()}, #srp_user{}, {HashAlgo::atom(), SignAlgo::atom()}, binary(), binary(), public_key:private_key()}) -> #client_key_exchange{} | #server_key_exchange{}. %% %% Description: Creates a keyexchange message. %%-------------------------------------------------------------------- key_exchange(client, _Version, {premaster_secret, Secret, {_, PublicKey, _}}) -> EncPremasterSecret = encrypted_premaster_secret(Secret, PublicKey), #client_key_exchange{exchange_keys = EncPremasterSecret}; key_exchange(client, _Version, {dh, PublicKey}) -> #client_key_exchange{ exchange_keys = #client_diffie_hellman_public{ dh_public = PublicKey} }; key_exchange(client, _Version, {ecdh, #'ECPrivateKey'{publicKey = ECPublicKey}}) -> #client_key_exchange{ exchange_keys = #client_ec_diffie_hellman_public{ dh_public = ECPublicKey} }; key_exchange(client, _Version, {psk, Identity}) -> #client_key_exchange{ exchange_keys = #client_psk_identity{ identity = Identity} }; key_exchange(client, _Version, {dhe_psk, Identity, PublicKey}) -> #client_key_exchange{ exchange_keys = #client_dhe_psk_identity{ identity = Identity, dh_public = PublicKey} }; key_exchange(client, _Version, {psk_premaster_secret, PskIdentity, Secret, {_, PublicKey, _}}) -> EncPremasterSecret = encrypted_premaster_secret(Secret, PublicKey), #client_key_exchange{ exchange_keys = #client_rsa_psk_identity{ identity = PskIdentity, exchange_keys = EncPremasterSecret}}; key_exchange(client, _Version, {srp, PublicKey}) -> #client_key_exchange{ exchange_keys = #client_srp_public{ srp_a = PublicKey} }; key_exchange(server, Version, {dh, {PublicKey, _}, #'DHParameter'{prime = P, base = G}, HashSign, ClientRandom, ServerRandom, PrivateKey}) -> ServerDHParams = #server_dh_params{dh_p = int_to_bin(P), dh_g = int_to_bin(G), dh_y = PublicKey}, enc_server_key_exchange(Version, ServerDHParams, HashSign, ClientRandom, ServerRandom, PrivateKey); key_exchange(server, Version, {ecdh, #'ECPrivateKey'{publicKey = ECPublicKey, parameters = ECCurve}, HashSign, ClientRandom, ServerRandom, PrivateKey}) -> ServerECParams = #server_ecdh_params{curve = ECCurve, public = ECPublicKey}, enc_server_key_exchange(Version, ServerECParams, HashSign, ClientRandom, ServerRandom, PrivateKey); key_exchange(server, Version, {psk, PskIdentityHint, HashSign, ClientRandom, ServerRandom, PrivateKey}) -> ServerPSKParams = #server_psk_params{hint = PskIdentityHint}, enc_server_key_exchange(Version, ServerPSKParams, HashSign, ClientRandom, ServerRandom, PrivateKey); key_exchange(server, Version, {dhe_psk, PskIdentityHint, {PublicKey, _}, #'DHParameter'{prime = P, base = G}, HashSign, ClientRandom, ServerRandom, PrivateKey}) -> ServerEDHPSKParams = #server_dhe_psk_params{ hint = PskIdentityHint, dh_params = #server_dh_params{dh_p = int_to_bin(P), dh_g = int_to_bin(G), dh_y = PublicKey} }, enc_server_key_exchange(Version, ServerEDHPSKParams, HashSign, ClientRandom, ServerRandom, PrivateKey); key_exchange(server, Version, {srp, {PublicKey, _}, #srp_user{generator = Generator, prime = Prime, salt = Salt}, HashSign, ClientRandom, ServerRandom, PrivateKey}) -> ServerSRPParams = #server_srp_params{srp_n = Prime, srp_g = Generator, srp_s = Salt, srp_b = PublicKey}, enc_server_key_exchange(Version, ServerSRPParams, HashSign, ClientRandom, ServerRandom, PrivateKey). %%-------------------------------------------------------------------- -spec finished(ssl_record:ssl_version(), client | server, integer(), binary(), ssl_handshake_history()) -> #finished{}. %% %% Description: Creates a handshake finished message %%------------------------------------------------------------------- finished(Version, Role, PrfAlgo, MasterSecret, {Handshake, _}) -> % use the current handshake #finished{verify_data = calc_finished(Version, Role, PrfAlgo, MasterSecret, Handshake)}. %% ---------- Handle handshake messages ---------- verify_server_key(#server_key_params{params_bin = EncParams, signature = Signature}, HashSign = {HashAlgo, _}, ConnectionStates, Version, PubKeyInfo) -> #{security_parameters := SecParams} = ssl_record:pending_connection_state(ConnectionStates, read), #security_parameters{client_random = ClientRandom, server_random = ServerRandom} = SecParams, Hash = server_key_exchange_hash(HashAlgo, <>), verify_signature(Version, Hash, HashSign, Signature, PubKeyInfo). %%-------------------------------------------------------------------- -spec certificate_verify(binary(), public_key_info(), ssl_record:ssl_version(), term(), binary(), ssl_handshake_history()) -> valid | #alert{}. %% %% Description: Checks that the certificate_verify message is valid. %%-------------------------------------------------------------------- certificate_verify(_, _, _, undefined, _, _) -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, invalid_certificate_verify_message); certificate_verify(Signature, PublicKeyInfo, Version, HashSign = {HashAlgo, _}, MasterSecret, {_, Handshake}) -> Hash = calc_certificate_verify(Version, HashAlgo, MasterSecret, Handshake), case verify_signature(Version, Hash, HashSign, Signature, PublicKeyInfo) of true -> valid; _ -> ?ALERT_REC(?FATAL, ?BAD_CERTIFICATE) end. %%-------------------------------------------------------------------- -spec verify_signature(ssl_record:ssl_version(), binary(), {term(), term()}, binary(), public_key_info()) -> true | false. %% %% Description: Checks that a public_key signature is valid. %%-------------------------------------------------------------------- verify_signature(_Version, _Hash, {_HashAlgo, anon}, _Signature, _) -> true; verify_signature({3, Minor}, Hash, {HashAlgo, rsa}, Signature, {?rsaEncryption, PubKey, _PubKeyParams}) when Minor >= 3 -> public_key:verify({digest, Hash}, HashAlgo, Signature, PubKey); verify_signature(_Version, Hash, _HashAlgo, Signature, {?rsaEncryption, PubKey, _PubKeyParams}) -> case public_key:decrypt_public(Signature, PubKey, [{rsa_pad, rsa_pkcs1_padding}]) of Hash -> true; _ -> false end; verify_signature(_Version, Hash, {HashAlgo, dsa}, Signature, {?'id-dsa', PublicKey, PublicKeyParams}) -> public_key:verify({digest, Hash}, HashAlgo, Signature, {PublicKey, PublicKeyParams}); verify_signature(_, Hash, {HashAlgo, _SignAlg}, Signature, {?'id-ecPublicKey', PublicKey, PublicKeyParams}) -> public_key:verify({digest, Hash}, HashAlgo, Signature, {PublicKey, PublicKeyParams}). %%-------------------------------------------------------------------- -spec certify(#certificate{}, db_handle(), certdb_ref(), #ssl_options{}, term(), client | server, inet:hostname() | inet:ip_address()) -> {der_cert(), public_key_info()} | #alert{}. %% %% Description: Handles a certificate handshake message %%-------------------------------------------------------------------- certify(#certificate{asn1_certificates = ASN1Certs}, CertDbHandle, CertDbRef, Opts, CRLDbHandle, Role, Host) -> ServerName = server_name(Opts#ssl_options.server_name_indication, Host, Role), [PeerCert | _] = ASN1Certs, try {TrustedCert, CertPath} = ssl_certificate:trusted_cert_and_path(ASN1Certs, CertDbHandle, CertDbRef, Opts#ssl_options.partial_chain), ValidationFunAndState = validation_fun_and_state(Opts#ssl_options.verify_fun, Role, CertDbHandle, CertDbRef, ServerName, Opts#ssl_options.crl_check, CRLDbHandle, CertPath), case public_key:pkix_path_validation(TrustedCert, CertPath, [{max_path_length, Opts#ssl_options.depth}, {verify_fun, ValidationFunAndState}]) of {ok, {PublicKeyInfo,_}} -> {PeerCert, PublicKeyInfo}; {error, Reason} -> path_validation_alert(Reason) end catch error:{badmatch,{asn1, Asn1Reason}} -> %% ASN-1 decode of certificate somehow failed ?ALERT_REC(?FATAL, ?CERTIFICATE_UNKNOWN, {failed_to_decode_certificate, Asn1Reason}); error:OtherReason -> ?ALERT_REC(?FATAL, ?INTERNAL_ERROR, {unexpected_error, OtherReason}) end. %%-------------------------------------------------------------------- -spec verify_connection(ssl_record:ssl_version(), #finished{}, client | server, integer(), binary(), ssl_handshake_history()) -> verified | #alert{}. %% %% Description: Checks the ssl handshake finished message to verify %% the connection. %%------------------------------------------------------------------- verify_connection(Version, #finished{verify_data = Data}, Role, PrfAlgo, MasterSecret, {_, Handshake}) -> %% use the previous hashes case calc_finished(Version, Role, PrfAlgo, MasterSecret, Handshake) of Data -> verified; _ -> ?ALERT_REC(?FATAL, ?DECRYPT_ERROR) end. %%-------------------------------------------------------------------- -spec init_handshake_history() -> ssl_handshake_history(). %% %% Description: Initialize the empty handshake history buffer. %%-------------------------------------------------------------------- init_handshake_history() -> {[], []}. %%-------------------------------------------------------------------- -spec update_handshake_history(ssl_handshake:ssl_handshake_history(), Data ::term(), boolean()) -> ssl_handshake:ssl_handshake_history(). %% %% Description: Update the handshake history buffer with Data. %%-------------------------------------------------------------------- update_handshake_history(Handshake, % special-case SSL2 client hello <>, true) -> update_handshake_history(Handshake, <>, true); update_handshake_history({Handshake0, _Prev}, Data, _) -> {[Data|Handshake0], Handshake0}. %% %%-------------------------------------------------------------------- %% -spec decrypt_premaster_secret(binary(), #'RSAPrivateKey'{}) -> binary(). %% %% %% %% Description: Public key decryption using the private key. %% %%-------------------------------------------------------------------- %% decrypt_premaster_secret(Secret, RSAPrivateKey) -> %% try public_key:decrypt_private(Secret, RSAPrivateKey, %% [{rsa_pad, rsa_pkcs1_padding}]) %% catch %% _:_ -> %% throw(?ALERT_REC(?FATAL, ?DECRYPT_ERROR)) %% end. premaster_secret(OtherPublicDhKey, MyPrivateKey, #'DHParameter'{} = Params) -> try public_key:compute_key(OtherPublicDhKey, MyPrivateKey, Params) catch error:computation_failed -> throw(?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER)) end; premaster_secret(PublicDhKey, PrivateDhKey, #server_dh_params{dh_p = Prime, dh_g = Base}) -> try crypto:compute_key(dh, PublicDhKey, PrivateDhKey, [Prime, Base]) catch error:computation_failed -> throw(?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER)) end; premaster_secret(#client_srp_public{srp_a = ClientPublicKey}, ServerKey, #srp_user{prime = Prime, verifier = Verifier}) -> case crypto:compute_key(srp, ClientPublicKey, ServerKey, {host, [Verifier, Prime, '6a']}) of error -> throw(?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER)); PremasterSecret -> PremasterSecret end; premaster_secret(#server_srp_params{srp_n = Prime, srp_g = Generator, srp_s = Salt, srp_b = Public}, ClientKeys, {Username, Password}) -> case ssl_srp_primes:check_srp_params(Generator, Prime) of ok -> DerivedKey = crypto:hash(sha, [Salt, crypto:hash(sha, [Username, <<$:>>, Password])]), case crypto:compute_key(srp, Public, ClientKeys, {user, [DerivedKey, Prime, Generator, '6a']}) of error -> throw(?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER)); PremasterSecret -> PremasterSecret end; _ -> throw(?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER)) end; premaster_secret(#client_rsa_psk_identity{ identity = PSKIdentity, exchange_keys = #encrypted_premaster_secret{premaster_secret = EncPMS} }, #'RSAPrivateKey'{} = Key, PSKLookup) -> PremasterSecret = premaster_secret(EncPMS, Key), psk_secret(PSKIdentity, PSKLookup, PremasterSecret); premaster_secret(#server_dhe_psk_params{ hint = IdentityHint, dh_params = #server_dh_params{dh_y = PublicDhKey} = Params}, PrivateDhKey, LookupFun) -> PremasterSecret = premaster_secret(PublicDhKey, PrivateDhKey, Params), psk_secret(IdentityHint, LookupFun, PremasterSecret); premaster_secret({rsa_psk, PSKIdentity}, PSKLookup, RSAPremasterSecret) -> psk_secret(PSKIdentity, PSKLookup, RSAPremasterSecret). premaster_secret(#client_dhe_psk_identity{ identity = PSKIdentity, dh_public = PublicDhKey}, PrivateKey, #'DHParameter'{} = Params, PSKLookup) -> PremasterSecret = premaster_secret(PublicDhKey, PrivateKey, Params), psk_secret(PSKIdentity, PSKLookup, PremasterSecret). premaster_secret(#client_psk_identity{identity = PSKIdentity}, PSKLookup) -> psk_secret(PSKIdentity, PSKLookup); premaster_secret({psk, PSKIdentity}, PSKLookup) -> psk_secret(PSKIdentity, PSKLookup); premaster_secret(#'ECPoint'{} = ECPoint, #'ECPrivateKey'{} = ECDHKeys) -> public_key:compute_key(ECPoint, ECDHKeys); premaster_secret(EncSecret, #'RSAPrivateKey'{} = RSAPrivateKey) -> try public_key:decrypt_private(EncSecret, RSAPrivateKey, [{rsa_pad, rsa_pkcs1_padding}]) catch _:_ -> throw(?ALERT_REC(?FATAL, ?DECRYPT_ERROR)) end. %%-------------------------------------------------------------------- -spec server_key_exchange_hash(md5sha | md5 | sha | sha224 |sha256 | sha384 | sha512, binary()) -> binary(). %% %% Description: Calculate server key exchange hash %%-------------------------------------------------------------------- server_key_exchange_hash(md5sha, Value) -> MD5 = crypto:hash(md5, Value), SHA = crypto:hash(sha, Value), <>; server_key_exchange_hash(Hash, Value) -> crypto:hash(Hash, Value). %%-------------------------------------------------------------------- -spec prf(ssl_record:ssl_version(), non_neg_integer(), binary(), binary(), [binary()], non_neg_integer()) -> {ok, binary()} | {error, undefined}. %% %% Description: use the TLS PRF to generate key material %%-------------------------------------------------------------------- prf({3,0}, _, _, _, _, _) -> {error, undefined}; prf({3,_N}, PRFAlgo, Secret, Label, Seed, WantedLength) -> {ok, tls_v1:prf(PRFAlgo, Secret, Label, Seed, WantedLength)}. %%-------------------------------------------------------------------- -spec select_hashsign(#hash_sign_algos{} | undefined, undefined | binary(), atom(), [atom()], ssl_record:ssl_version()) -> {atom(), atom()} | undefined | #alert{}. %% %% Description: Handles signature_algorithms hello extension (server) %%-------------------------------------------------------------------- select_hashsign(_, undefined, _, _, _Version) -> {null, anon}; %% The signature_algorithms extension was introduced with TLS 1.2. Ignore it if we have %% negotiated a lower version. select_hashsign(HashSigns, Cert, KeyExAlgo, undefined, {Major, Minor} = Version) when Major >= 3 andalso Minor >= 3-> select_hashsign(HashSigns, Cert, KeyExAlgo, tls_v1:default_signature_algs(Version), Version); select_hashsign(#hash_sign_algos{hash_sign_algos = HashSigns}, Cert, KeyExAlgo, SupportedHashSigns, {Major, Minor}) when Major >= 3 andalso Minor >= 3 -> #'OTPCertificate'{tbsCertificate = TBSCert} = public_key:pkix_decode_cert(Cert, otp), #'OTPCertificate'{tbsCertificate = TBSCert, signatureAlgorithm = {_,SignAlgo, _}} = public_key:pkix_decode_cert(Cert, otp), #'OTPSubjectPublicKeyInfo'{algorithm = {_, SubjAlgo, _}} = TBSCert#'OTPTBSCertificate'.subjectPublicKeyInfo, Sign = sign_algo(SignAlgo), SubSing = sign_algo(SubjAlgo), case lists:filter(fun({_, S} = Algos) when S == Sign -> is_acceptable_hash_sign(Algos, Sign, SubSing, KeyExAlgo, SupportedHashSigns); (_) -> false end, HashSigns) of [] -> ?ALERT_REC(?FATAL, ?INSUFFICIENT_SECURITY, no_suitable_signature_algorithm); [HashSign | _] -> HashSign end; select_hashsign(_, Cert, _, _, Version) -> #'OTPCertificate'{tbsCertificate = TBSCert} = public_key:pkix_decode_cert(Cert, otp), #'OTPSubjectPublicKeyInfo'{algorithm = {_,Algo, _}} = TBSCert#'OTPTBSCertificate'.subjectPublicKeyInfo, select_hashsign_algs(undefined, Algo, Version). %%-------------------------------------------------------------------- -spec select_hashsign(#certificate_request{}, binary(), [atom()], ssl_record:ssl_version()) -> {atom(), atom()} | #alert{}. %% %% Description: Handles signature algorithms selection for certificate requests (client) %%-------------------------------------------------------------------- select_hashsign(#certificate_request{}, undefined, _, {Major, Minor}) when Major >= 3 andalso Minor >= 3-> %% There client does not have a certificate and will send an empty reply, the server may fail %% or accept the connection by its own preference. No signature algorihms needed as there is %% no certificate to verify. {undefined, undefined}; select_hashsign(#certificate_request{hashsign_algorithms = #hash_sign_algos{hash_sign_algos = HashSigns}, certificate_types = Types}, Cert, SupportedHashSigns, {Major, Minor}) when Major >= 3 andalso Minor >= 3-> #'OTPCertificate'{tbsCertificate = TBSCert} = public_key:pkix_decode_cert(Cert, otp), #'OTPCertificate'{tbsCertificate = TBSCert, signatureAlgorithm = {_,SignAlgo, _}} = public_key:pkix_decode_cert(Cert, otp), #'OTPSubjectPublicKeyInfo'{algorithm = {_, SubjAlgo, _}} = TBSCert#'OTPTBSCertificate'.subjectPublicKeyInfo, Sign = sign_algo(SignAlgo), SubSign = sign_algo(SubjAlgo), case is_acceptable_cert_type(SubSign, HashSigns, Types) andalso is_supported_sign(Sign, HashSigns) of true -> case lists:filter(fun({_, S} = Algos) when S == SubSign -> is_acceptable_hash_sign(Algos, SupportedHashSigns); (_) -> false end, HashSigns) of [] -> ?ALERT_REC(?FATAL, ?INSUFFICIENT_SECURITY, no_suitable_signature_algorithm); [HashSign | _] -> HashSign end; false -> ?ALERT_REC(?FATAL, ?INSUFFICIENT_SECURITY, no_suitable_signature_algorithm) end; select_hashsign(#certificate_request{}, Cert, _, Version) -> select_hashsign(undefined, Cert, undefined, [], Version). %%-------------------------------------------------------------------- -spec select_hashsign_algs({atom(), atom()}| undefined, oid(), ssl_record:ssl_version()) -> {atom(), atom()}. %% Description: For TLS 1.2 hash function and signature algorithm pairs can be %% negotiated with the signature_algorithms extension, %% for previous versions always use appropriate defaults. %% RFC 5246, Sect. 7.4.1.4.1. Signature Algorithms %% If the client does not send the signature_algorithms extension, the %% server MUST do the following: (e.i defaults for TLS 1.2) %% %% - If the negotiated key exchange algorithm is one of (RSA, DHE_RSA, %% DH_RSA, RSA_PSK, ECDH_RSA, ECDHE_RSA), behave as if client had %% sent the value {sha1,rsa}. %% %% - If the negotiated key exchange algorithm is one of (DHE_DSS, %% DH_DSS), behave as if the client had sent the value {sha1,dsa}. %% %% - If the negotiated key exchange algorithm is one of (ECDH_ECDSA, %% ECDHE_ECDSA), behave as if the client had sent value {sha1,ecdsa}. %%-------------------------------------------------------------------- select_hashsign_algs(HashSign, _, {Major, Minor}) when HashSign =/= undefined andalso Major >= 3 andalso Minor >= 3 -> HashSign; select_hashsign_algs(undefined, ?rsaEncryption, {Major, Minor}) when Major >= 3 andalso Minor >= 3 -> {sha, rsa}; select_hashsign_algs(undefined,?'id-ecPublicKey', _) -> {sha, ecdsa}; select_hashsign_algs(undefined, ?rsaEncryption, _) -> {md5sha, rsa}; select_hashsign_algs(undefined, ?'id-dsa', _) -> {sha, dsa}. %%-------------------------------------------------------------------- -spec master_secret(ssl_record:ssl_version(), #session{} | binary(), ssl_record:connection_states(), client | server) -> {binary(), ssl_record:connection_states()} | #alert{}. %% %% Description: Sets or calculates the master secret and calculate keys, %% updating the pending connection states. The Mastersecret and the update %% connection states are returned or an alert if the calculation fails. %%------------------------------------------------------------------- master_secret(Version, #session{master_secret = Mastersecret}, ConnectionStates, Role) -> #{security_parameters := SecParams} = ssl_record:pending_connection_state(ConnectionStates, read), try master_secret(Version, Mastersecret, SecParams, ConnectionStates, Role) catch exit:_ -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, key_calculation_failure) end; master_secret(Version, PremasterSecret, ConnectionStates, Role) -> #{security_parameters := SecParams} = ssl_record:pending_connection_state(ConnectionStates, read), #security_parameters{prf_algorithm = PrfAlgo, client_random = ClientRandom, server_random = ServerRandom} = SecParams, try master_secret(Version, calc_master_secret(Version,PrfAlgo,PremasterSecret, ClientRandom, ServerRandom), SecParams, ConnectionStates, Role) catch exit:_ -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, master_secret_calculation_failure) end. %%-------------Encode/Decode -------------------------------- encode_handshake(#next_protocol{selected_protocol = SelectedProtocol}, _Version) -> PaddingLength = 32 - ((byte_size(SelectedProtocol) + 2) rem 32), {?NEXT_PROTOCOL, <>}; encode_handshake(#server_hello{server_version = {Major, Minor}, random = Random, session_id = Session_ID, cipher_suite = CipherSuite, compression_method = Comp_method, extensions = #hello_extensions{} = Extensions}, _Version) -> SID_length = byte_size(Session_ID), ExtensionsBin = encode_hello_extensions(Extensions), {?SERVER_HELLO, <>}; encode_handshake(#certificate{asn1_certificates = ASN1CertList}, _Version) -> ASN1Certs = certs_from_list(ASN1CertList), ACLen = erlang:iolist_size(ASN1Certs), {?CERTIFICATE, <>}; encode_handshake(#server_key_exchange{exchange_keys = Keys}, _Version) -> {?SERVER_KEY_EXCHANGE, Keys}; encode_handshake(#server_key_params{params_bin = Keys, hashsign = HashSign, signature = Signature}, Version) -> EncSign = enc_sign(HashSign, Signature, Version), {?SERVER_KEY_EXCHANGE, <>}; encode_handshake(#certificate_request{certificate_types = CertTypes, hashsign_algorithms = #hash_sign_algos{hash_sign_algos = HashSignAlgos}, certificate_authorities = CertAuths}, {Major, Minor}) when Major == 3, Minor >= 3 -> HashSigns= << <<(ssl_cipher:hash_algorithm(Hash)):8, (ssl_cipher:sign_algorithm(Sign)):8>> || {Hash, Sign} <- HashSignAlgos >>, CertTypesLen = byte_size(CertTypes), HashSignsLen = byte_size(HashSigns), CertAuthsLen = byte_size(CertAuths), {?CERTIFICATE_REQUEST, <> }; encode_handshake(#certificate_request{certificate_types = CertTypes, certificate_authorities = CertAuths}, _Version) -> CertTypesLen = byte_size(CertTypes), CertAuthsLen = byte_size(CertAuths), {?CERTIFICATE_REQUEST, <> }; encode_handshake(#server_hello_done{}, _Version) -> {?SERVER_HELLO_DONE, <<>>}; encode_handshake(#client_key_exchange{exchange_keys = ExchangeKeys}, Version) -> {?CLIENT_KEY_EXCHANGE, encode_client_key(ExchangeKeys, Version)}; encode_handshake(#certificate_verify{signature = BinSig, hashsign_algorithm = HashSign}, Version) -> EncSig = enc_sign(HashSign, BinSig, Version), {?CERTIFICATE_VERIFY, EncSig}; encode_handshake(#finished{verify_data = VerifyData}, _Version) -> {?FINISHED, VerifyData}. encode_hello_extensions(#hello_extensions{} = Extensions) -> encode_hello_extensions(hello_extensions_list(Extensions), <<>>). encode_hello_extensions([], <<>>) -> <<>>; encode_hello_extensions([], Acc) -> Size = byte_size(Acc), <>; encode_hello_extensions([#alpn{extension_data = ExtensionData} | Rest], Acc) -> Len = byte_size(ExtensionData), ExtLen = Len + 2, encode_hello_extensions(Rest, <>); encode_hello_extensions([#next_protocol_negotiation{extension_data = ExtensionData} | Rest], Acc) -> Len = byte_size(ExtensionData), encode_hello_extensions(Rest, <>); encode_hello_extensions([#renegotiation_info{renegotiated_connection = undefined} | Rest], Acc) -> encode_hello_extensions(Rest, Acc); encode_hello_extensions([#renegotiation_info{renegotiated_connection = ?byte(0) = Info} | Rest], Acc) -> Len = byte_size(Info), encode_hello_extensions(Rest, <>); encode_hello_extensions([#renegotiation_info{renegotiated_connection = Info} | Rest], Acc) -> InfoLen = byte_size(Info), Len = InfoLen +1, encode_hello_extensions(Rest, <>); encode_hello_extensions([#elliptic_curves{elliptic_curve_list = EllipticCurves} | Rest], Acc) -> EllipticCurveList = << <<(tls_v1:oid_to_enum(X)):16>> || X <- EllipticCurves>>, ListLen = byte_size(EllipticCurveList), Len = ListLen + 2, encode_hello_extensions(Rest, <>); encode_hello_extensions([#ec_point_formats{ec_point_format_list = ECPointFormats} | Rest], Acc) -> ECPointFormatList = list_to_binary(ECPointFormats), ListLen = byte_size(ECPointFormatList), Len = ListLen + 1, encode_hello_extensions(Rest, <>); encode_hello_extensions([#srp{username = UserName} | Rest], Acc) -> SRPLen = byte_size(UserName), Len = SRPLen + 2, encode_hello_extensions(Rest, <>); encode_hello_extensions([#hash_sign_algos{hash_sign_algos = HashSignAlgos} | Rest], Acc) -> SignAlgoList = << <<(ssl_cipher:hash_algorithm(Hash)):8, (ssl_cipher:sign_algorithm(Sign)):8>> || {Hash, Sign} <- HashSignAlgos >>, ListLen = byte_size(SignAlgoList), Len = ListLen + 2, encode_hello_extensions(Rest, <>); encode_hello_extensions([#sni{hostname = Hostname} | Rest], Acc) -> HostLen = length(Hostname), HostnameBin = list_to_binary(Hostname), % Hostname type (1 byte) + Hostname length (2 bytes) + Hostname (HostLen bytes) ServerNameLength = 1 + 2 + HostLen, % ServerNameListSize (2 bytes) + ServerNameLength ExtLength = 2 + ServerNameLength, encode_hello_extensions(Rest, <>). enc_server_key_exchange(Version, Params, {HashAlgo, SignAlgo}, ClientRandom, ServerRandom, PrivateKey) -> EncParams = encode_server_key(Params), case HashAlgo of null -> #server_key_params{params = Params, params_bin = EncParams, hashsign = {null, anon}, signature = <<>>}; _ -> Hash = server_key_exchange_hash(HashAlgo, <>), Signature = digitally_signed(Version, Hash, HashAlgo, PrivateKey), #server_key_params{params = Params, params_bin = EncParams, hashsign = {HashAlgo, SignAlgo}, signature = Signature} end. %%-------------------------------------------------------------------- -spec decode_client_key(binary(), ssl_cipher:key_algo(), ssl_record:ssl_version()) -> #encrypted_premaster_secret{} | #client_diffie_hellman_public{} | #client_ec_diffie_hellman_public{} | #client_psk_identity{} | #client_dhe_psk_identity{} | #client_rsa_psk_identity{} | #client_srp_public{}. %% %% Description: Decode client_key data and return appropriate type %%-------------------------------------------------------------------- decode_client_key(ClientKey, Type, Version) -> dec_client_key(ClientKey, key_exchange_alg(Type), Version). %%-------------------------------------------------------------------- -spec decode_server_key(binary(), ssl_cipher:key_algo(), ssl_record:ssl_version()) -> #server_key_params{}. %% %% Description: Decode server_key data and return appropriate type %%-------------------------------------------------------------------- decode_server_key(ServerKey, Type, Version) -> dec_server_key(ServerKey, key_exchange_alg(Type), Version). %% %% Description: Encode and decode functions for ALPN extension data. %%-------------------------------------------------------------------- %% While the RFC opens the door to allow ALPN during renegotiation, in practice %% this does not work and it is recommended to ignore any ALPN extension during %% renegotiation, as done here. encode_alpn(_, true) -> undefined; encode_alpn(undefined, _) -> undefined; encode_alpn(Protocols, _) -> #alpn{extension_data = lists:foldl(fun encode_protocol/2, <<>>, Protocols)}. decode_alpn(undefined) -> undefined; decode_alpn(#alpn{extension_data=Data}) -> decode_protocols(Data, []). encode_client_protocol_negotiation(undefined, _) -> undefined; encode_client_protocol_negotiation(_, false) -> #next_protocol_negotiation{extension_data = <<>>}; encode_client_protocol_negotiation(_, _) -> undefined. encode_protocols_advertised_on_server(undefined) -> undefined; encode_protocols_advertised_on_server(Protocols) -> #next_protocol_negotiation{extension_data = lists:foldl(fun encode_protocol/2, <<>>, Protocols)}. decode_handshake(_, ?HELLO_REQUEST, <<>>) -> #hello_request{}; decode_handshake(_, ?NEXT_PROTOCOL, <>) -> #next_protocol{selected_protocol = SelectedProtocol}; decode_handshake(_Version, ?SERVER_HELLO, <>) -> #server_hello{ server_version = {Major,Minor}, random = Random, session_id = Session_ID, cipher_suite = Cipher_suite, compression_method = Comp_method, extensions = #hello_extensions{}}; decode_handshake(_Version, ?SERVER_HELLO, <>) -> HelloExtensions = decode_hello_extensions(Extensions), #server_hello{ server_version = {Major,Minor}, random = Random, session_id = Session_ID, cipher_suite = Cipher_suite, compression_method = Comp_method, extensions = HelloExtensions}; decode_handshake(_Version, ?CERTIFICATE, <>) -> #certificate{asn1_certificates = certs_to_list(ASN1Certs)}; decode_handshake(_Version, ?SERVER_KEY_EXCHANGE, Keys) -> #server_key_exchange{exchange_keys = Keys}; decode_handshake({Major, Minor}, ?CERTIFICATE_REQUEST, <>) when Major >= 3, Minor >= 3 -> HashSignAlgos = [{ssl_cipher:hash_algorithm(Hash), ssl_cipher:sign_algorithm(Sign)} || <> <= HashSigns], #certificate_request{certificate_types = CertTypes, hashsign_algorithms = #hash_sign_algos{hash_sign_algos = HashSignAlgos}, certificate_authorities = CertAuths}; decode_handshake(_Version, ?CERTIFICATE_REQUEST, <>) -> #certificate_request{certificate_types = CertTypes, certificate_authorities = CertAuths}; decode_handshake(_Version, ?SERVER_HELLO_DONE, <<>>) -> #server_hello_done{}; decode_handshake({Major, Minor}, ?CERTIFICATE_VERIFY,<>) when Major == 3, Minor >= 3 -> #certificate_verify{hashsign_algorithm = dec_hashsign(HashSign), signature = Signature}; decode_handshake(_Version, ?CERTIFICATE_VERIFY,<>)-> #certificate_verify{signature = Signature}; decode_handshake(_Version, ?CLIENT_KEY_EXCHANGE, PKEPMS) -> #client_key_exchange{exchange_keys = PKEPMS}; decode_handshake(_Version, ?FINISHED, VerifyData) -> #finished{verify_data = VerifyData}; decode_handshake(_, Message, _) -> throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, {unknown_or_malformed_handshake, Message})). %%-------------------------------------------------------------------- -spec decode_hello_extensions({client, binary()} | binary()) -> #hello_extensions{}. %% %% Description: Decodes TLS hello extensions %%-------------------------------------------------------------------- decode_hello_extensions({client, <<>>}) -> #hello_extensions{}; decode_hello_extensions({client, <>}) -> decode_hello_extensions(Extensions); decode_hello_extensions(Extensions) -> dec_hello_extensions(Extensions, #hello_extensions{}). dec_server_key(<> = KeyStruct, ?KEY_EXCHANGE_DIFFIE_HELLMAN, Version) -> Params = #server_dh_params{dh_p = P, dh_g = G, dh_y = Y}, {BinMsg, HashSign, Signature} = dec_server_key_params(PLen + GLen + YLen + 6, KeyStruct, Version), #server_key_params{params = Params, params_bin = BinMsg, hashsign = HashSign, signature = Signature}; %% ECParameters with named_curve %% TODO: explicit curve dec_server_key(<> = KeyStruct, ?KEY_EXCHANGE_EC_DIFFIE_HELLMAN, Version) -> Params = #server_ecdh_params{curve = {namedCurve, tls_v1:enum_to_oid(CurveID)}, public = ECPoint}, {BinMsg, HashSign, Signature} = dec_server_key_params(PointLen + 4, KeyStruct, Version), #server_key_params{params = Params, params_bin = BinMsg, hashsign = HashSign, signature = Signature}; dec_server_key(<> = KeyStruct, KeyExchange, Version) when KeyExchange == ?KEY_EXCHANGE_PSK; KeyExchange == ?KEY_EXCHANGE_RSA_PSK -> Params = #server_psk_params{ hint = PskIdentityHint}, {BinMsg, HashSign, Signature} = dec_server_key_params(Len + 2, KeyStruct, Version), #server_key_params{params = Params, params_bin = BinMsg, hashsign = HashSign, signature = Signature}; dec_server_key(<> = KeyStruct, ?KEY_EXCHANGE_DHE_PSK, Version) -> DHParams = #server_dh_params{dh_p = P, dh_g = G, dh_y = Y}, Params = #server_dhe_psk_params{ hint = IdentityHint, dh_params = DHParams}, {BinMsg, HashSign, Signature} = dec_server_key_params(Len + PLen + GLen + YLen + 8, KeyStruct, Version), #server_key_params{params = Params, params_bin = BinMsg, hashsign = HashSign, signature = Signature}; dec_server_key(<> = KeyStruct, ?KEY_EXCHANGE_SRP, Version) -> Params = #server_srp_params{srp_n = N, srp_g = G, srp_s = S, srp_b = B}, {BinMsg, HashSign, Signature} = dec_server_key_params(NLen + GLen + SLen + BLen + 7, KeyStruct, Version), #server_key_params{params = Params, params_bin = BinMsg, hashsign = HashSign, signature = Signature}; dec_server_key(_, KeyExchange, _) -> throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, {unknown_or_malformed_key_exchange, KeyExchange})). %%-------------------------------------------------------------------- -spec decode_suites('2_bytes'|'3_bytes', binary()) -> list(). %% %% Description: %%-------------------------------------------------------------------- decode_suites('2_bytes', Dec) -> from_2bytes(Dec); decode_suites('3_bytes', Dec) -> from_3bytes(Dec). %%-------------Cipeher suite handling -------------------------------- available_suites(UserSuites, Version) -> lists:filtermap(fun(Suite) -> lists:member(Suite, ssl_cipher:all_suites(Version)) end, UserSuites). available_suites(ServerCert, UserSuites, Version, undefined, Curve) -> ssl_cipher:filter(ServerCert, available_suites(UserSuites, Version)) -- unavailable_ecc_suites(Curve); available_suites(ServerCert, UserSuites, Version, HashSigns, Curve) -> Suites = available_suites(ServerCert, UserSuites, Version, undefined, Curve), filter_hashsigns(Suites, [ssl_cipher:suite_definition(Suite) || Suite <- Suites], HashSigns, []). filter_hashsigns([], [], _, Acc) -> lists:reverse(Acc); filter_hashsigns([Suite | Suites], [{KeyExchange,_,_,_} | Algos], HashSigns, Acc) when KeyExchange == dhe_ecdsa; KeyExchange == ecdhe_ecdsa -> do_filter_hashsigns(ecdsa, Suite, Suites, Algos, HashSigns, Acc); filter_hashsigns([Suite | Suites], [{KeyExchange,_,_,_} | Algos], HashSigns, Acc) when KeyExchange == rsa; KeyExchange == dhe_rsa; KeyExchange == ecdhe_rsa; KeyExchange == srp_rsa; KeyExchange == rsa_psk -> do_filter_hashsigns(rsa, Suite, Suites, Algos, HashSigns, Acc); filter_hashsigns([Suite | Suites], [{KeyExchange,_,_,_} | Algos], HashSigns, Acc) when KeyExchange == dhe_dss; KeyExchange == srp_dss -> do_filter_hashsigns(dsa, Suite, Suites, Algos, HashSigns, Acc); filter_hashsigns([Suite | Suites], [{KeyExchange,_,_,_} | Algos], HashSigns, Acc) when KeyExchange == dh_dss; KeyExchange == dh_rsa; KeyExchange == dh_ecdsa; KeyExchange == ecdh_rsa; KeyExchange == ecdh_ecdsa -> %% Fixed DH certificates MAY be signed with any hash/signature %% algorithm pair appearing in the hash_sign extension. The names %% DH_DSS, DH_RSA, ECDH_ECDSA, and ECDH_RSA are historical. filter_hashsigns(Suites, Algos, HashSigns, [Suite| Acc]); filter_hashsigns([Suite | Suites], [{KeyExchange,_,_,_} | Algos], HashSigns, Acc) when KeyExchange == dh_anon; KeyExchange == ecdh_anon; KeyExchange == srp_anon; KeyExchange == psk; KeyExchange == dhe_psk -> %% In this case hashsigns is not used as the kexchange is anonaymous filter_hashsigns(Suites, Algos, HashSigns, [Suite| Acc]). do_filter_hashsigns(SignAlgo, Suite, Suites, Algos, HashSigns, Acc) -> case lists:keymember(SignAlgo, 2, HashSigns) of true -> filter_hashsigns(Suites, Algos, HashSigns, [Suite| Acc]); false -> filter_hashsigns(Suites, Algos, HashSigns, Acc) end. unavailable_ecc_suites(no_curve) -> ssl_cipher:ec_keyed_suites(); unavailable_ecc_suites(_) -> []. cipher_suites(Suites, false) -> [?TLS_EMPTY_RENEGOTIATION_INFO_SCSV | Suites]; cipher_suites(Suites, true) -> Suites. select_session(SuggestedSessionId, CipherSuites, HashSigns, Compressions, Port, #session{ecc = ECCCurve} = Session, Version, #ssl_options{ciphers = UserSuites, honor_cipher_order = HonorCipherOrder} = SslOpts, Cache, CacheCb, Cert) -> {SessionId, Resumed} = ssl_session:server_id(Port, SuggestedSessionId, SslOpts, Cert, Cache, CacheCb), case Resumed of undefined -> Suites = available_suites(Cert, UserSuites, Version, HashSigns, ECCCurve), CipherSuite = select_cipher_suite(CipherSuites, Suites, HonorCipherOrder), Compression = select_compression(Compressions), {new, Session#session{session_id = SessionId, cipher_suite = CipherSuite, compression_method = Compression}}; _ -> {resumed, Resumed} end. %% Deprecated? supported_ecc({Major, Minor}) when ((Major == 3) and (Minor >= 1)) orelse (Major > 3) -> Curves = tls_v1:ecc_curves(Minor), #elliptic_curves{elliptic_curve_list = Curves}; supported_ecc(_) -> #elliptic_curves{elliptic_curve_list = []}. %%-------------certificate handling -------------------------------- certificate_types(_, {N, M}) when N >= 3 andalso M >= 3 -> case proplists:get_bool(ecdsa, proplists:get_value(public_keys, crypto:supports())) of true -> <>; false -> <> end; certificate_types({KeyExchange, _, _, _}, _) when KeyExchange == rsa; KeyExchange == dh_rsa; KeyExchange == dhe_rsa; KeyExchange == ecdhe_rsa -> <>; certificate_types({KeyExchange, _, _, _}, _) when KeyExchange == dh_dss; KeyExchange == dhe_dss; KeyExchange == srp_dss -> <>; certificate_types({KeyExchange, _, _, _}, _) when KeyExchange == dh_ecdsa; KeyExchange == dhe_ecdsa; KeyExchange == ecdh_ecdsa; KeyExchange == ecdhe_ecdsa -> <>; certificate_types(_, _) -> <>. certificate_authorities(CertDbHandle, CertDbRef) -> Authorities = certificate_authorities_from_db(CertDbHandle, CertDbRef), Enc = fun(#'OTPCertificate'{tbsCertificate=TBSCert}) -> OTPSubj = TBSCert#'OTPTBSCertificate'.subject, DNEncodedBin = public_key:pkix_encode('Name', OTPSubj, otp), DNEncodedLen = byte_size(DNEncodedBin), <> end, list_to_binary([Enc(Cert) || {_, Cert} <- Authorities]). certificate_authorities_from_db(CertDbHandle, CertDbRef) when is_reference(CertDbRef) -> ConnectionCerts = fun({{Ref, _, _}, Cert}, Acc) when Ref == CertDbRef -> [Cert | Acc]; (_, Acc) -> Acc end, ssl_pkix_db:foldl(ConnectionCerts, [], CertDbHandle); certificate_authorities_from_db(_CertDbHandle, {extracted, CertDbData}) -> %% Cache disabled, Ref contains data lists:foldl(fun({decoded, {_Key,Cert}}, Acc) -> [Cert | Acc] end, [], CertDbData). %%-------------Extension handling -------------------------------- handle_client_hello_extensions(RecordCB, Random, ClientCipherSuites, #hello_extensions{renegotiation_info = Info, srp = SRP, ec_point_formats = ECCFormat, alpn = ALPN, next_protocol_negotiation = NextProtocolNegotiation}, Version, #ssl_options{secure_renegotiate = SecureRenegotation, alpn_preferred_protocols = ALPNPreferredProtocols} = Opts, #session{cipher_suite = NegotiatedCipherSuite, compression_method = Compression} = Session0, ConnectionStates0, Renegotiation) -> Session = handle_srp_extension(SRP, Session0), ConnectionStates = handle_renegotiation_extension(server, RecordCB, Version, Info, Random, NegotiatedCipherSuite, ClientCipherSuites, Compression, ConnectionStates0, Renegotiation, SecureRenegotation), ServerHelloExtensions = #hello_extensions{ renegotiation_info = renegotiation_info(RecordCB, server, ConnectionStates, Renegotiation), ec_point_formats = server_ecc_extension(Version, ECCFormat) }, %% If we receive an ALPN extension and have ALPN configured for this connection, %% we handle it. Otherwise we check for the NPN extension. if ALPN =/= undefined, ALPNPreferredProtocols =/= undefined -> case handle_alpn_extension(ALPNPreferredProtocols, decode_alpn(ALPN)) of #alert{} = Alert -> Alert; Protocol -> {Session, ConnectionStates, Protocol, ServerHelloExtensions#hello_extensions{alpn=encode_alpn([Protocol], Renegotiation)}} end; true -> ProtocolsToAdvertise = handle_next_protocol_extension(NextProtocolNegotiation, Renegotiation, Opts), {Session, ConnectionStates, undefined, ServerHelloExtensions#hello_extensions{next_protocol_negotiation= encode_protocols_advertised_on_server(ProtocolsToAdvertise)}} end. handle_server_hello_extensions(RecordCB, Random, CipherSuite, Compression, #hello_extensions{renegotiation_info = Info, alpn = ALPN, next_protocol_negotiation = NextProtocolNegotiation}, Version, #ssl_options{secure_renegotiate = SecureRenegotation, next_protocol_selector = NextProtoSelector}, ConnectionStates0, Renegotiation) -> ConnectionStates = handle_renegotiation_extension(client, RecordCB, Version, Info, Random, CipherSuite, undefined, Compression, ConnectionStates0, Renegotiation, SecureRenegotation), %% If we receive an ALPN extension then this is the protocol selected, %% otherwise handle the NPN extension. case decode_alpn(ALPN) of %% ServerHello contains exactly one protocol: the one selected. %% We also ignore the ALPN extension during renegotiation (see encode_alpn/2). [Protocol] when not Renegotiation -> {ConnectionStates, alpn, Protocol}; undefined -> case handle_next_protocol(NextProtocolNegotiation, NextProtoSelector, Renegotiation) of #alert{} = Alert -> Alert; Protocol -> {ConnectionStates, npn, Protocol} end; {error, Reason} -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, Reason); [] -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, no_protocols_in_server_hello); [_|_] -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, too_many_protocols_in_server_hello) end. select_version(RecordCB, ClientVersion, Versions) -> do_select_version(RecordCB, ClientVersion, Versions). do_select_version(_, ClientVersion, []) -> ClientVersion; do_select_version(RecordCB, ClientVersion, [Version | Versions]) -> case RecordCB:is_higher(Version, ClientVersion) of true -> %% Version too high for client - keep looking do_select_version(RecordCB, ClientVersion, Versions); false -> %% Version ok for client - look for a higher do_select_version(RecordCB, ClientVersion, Versions, Version) end. %% do_select_version(_, _, [], GoodVersion) -> GoodVersion; do_select_version( RecordCB, ClientVersion, [Version | Versions], GoodVersion) -> BetterVersion = case RecordCB:is_higher(Version, ClientVersion) of true -> %% Version too high for client GoodVersion; false -> %% Version ok for client case RecordCB:is_higher(Version, GoodVersion) of true -> %% Use higher version Version; false -> GoodVersion end end, do_select_version(RecordCB, ClientVersion, Versions, BetterVersion). renegotiation_info(_, client, _, false) -> #renegotiation_info{renegotiated_connection = undefined}; renegotiation_info(_RecordCB, server, ConnectionStates, false) -> ConnectionState = ssl_record:current_connection_state(ConnectionStates, read), case maps:get(secure_renegotiation, ConnectionState) of true -> #renegotiation_info{renegotiated_connection = ?byte(0)}; false -> #renegotiation_info{renegotiated_connection = undefined} end; renegotiation_info(_RecordCB, client, ConnectionStates, true) -> ConnectionState = ssl_record:current_connection_state(ConnectionStates, read), case maps:get(secure_renegotiation, ConnectionState) of true -> Data = maps:get(client_verify_data, ConnectionState), #renegotiation_info{renegotiated_connection = Data}; false -> #renegotiation_info{renegotiated_connection = undefined} end; renegotiation_info(_RecordCB, server, ConnectionStates, true) -> ConnectionState = ssl_record:current_connection_state(ConnectionStates, read), case maps:get(secure_renegotiation, ConnectionState) of true -> CData = maps:get(client_verify_data, ConnectionState), SData = maps:get(server_verify_data, ConnectionState), #renegotiation_info{renegotiated_connection = <>}; false -> #renegotiation_info{renegotiated_connection = undefined} end. handle_renegotiation_info(_RecordCB, _, #renegotiation_info{renegotiated_connection = ?byte(0)}, ConnectionStates, false, _, _) -> {ok, ssl_record:set_renegotiation_flag(true, ConnectionStates)}; handle_renegotiation_info(_RecordCB, server, undefined, ConnectionStates, _, _, CipherSuites) -> case is_member(?TLS_EMPTY_RENEGOTIATION_INFO_SCSV, CipherSuites) of true -> {ok, ssl_record:set_renegotiation_flag(true, ConnectionStates)}; false -> {ok, ssl_record:set_renegotiation_flag(false, ConnectionStates)} end; handle_renegotiation_info(_RecordCB, _, undefined, ConnectionStates, false, _, _) -> {ok, ssl_record:set_renegotiation_flag(false, ConnectionStates)}; handle_renegotiation_info(_RecordCB, client, #renegotiation_info{renegotiated_connection = ClientServerVerify}, ConnectionStates, true, _, _) -> ConnectionState = ssl_record:current_connection_state(ConnectionStates, read), CData = maps:get(client_verify_data, ConnectionState), SData = maps:get(server_verify_data, ConnectionState), case <> == ClientServerVerify of true -> {ok, ConnectionStates}; false -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, client_renegotiation) end; handle_renegotiation_info(_RecordCB, server, #renegotiation_info{renegotiated_connection = ClientVerify}, ConnectionStates, true, _, CipherSuites) -> case is_member(?TLS_EMPTY_RENEGOTIATION_INFO_SCSV, CipherSuites) of true -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, {server_renegotiation, empty_renegotiation_info_scsv}); false -> ConnectionState = ssl_record:current_connection_state(ConnectionStates, read), Data = maps:get(client_verify_data, ConnectionState), case Data == ClientVerify of true -> {ok, ConnectionStates}; false -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, server_renegotiation) end end; handle_renegotiation_info(RecordCB, client, undefined, ConnectionStates, true, SecureRenegotation, _) -> handle_renegotiation_info(RecordCB, ConnectionStates, SecureRenegotation); handle_renegotiation_info(RecordCB, server, undefined, ConnectionStates, true, SecureRenegotation, CipherSuites) -> case is_member(?TLS_EMPTY_RENEGOTIATION_INFO_SCSV, CipherSuites) of true -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, {server_renegotiation, empty_renegotiation_info_scsv}); false -> handle_renegotiation_info(RecordCB, ConnectionStates, SecureRenegotation) end. handle_renegotiation_info(_RecordCB, ConnectionStates, SecureRenegotation) -> ConnectionState = ssl_record:current_connection_state(ConnectionStates, read), case {SecureRenegotation, maps:get(secure_renegotiation, ConnectionState)} of {_, true} -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, already_secure); {true, false} -> ?ALERT_REC(?FATAL, ?NO_RENEGOTIATION); {false, false} -> {ok, ConnectionStates} end. hello_extensions_list(#hello_extensions{renegotiation_info = RenegotiationInfo, srp = SRP, signature_algs = HashSigns, ec_point_formats = EcPointFormats, elliptic_curves = EllipticCurves, alpn = ALPN, next_protocol_negotiation = NextProtocolNegotiation, sni = Sni}) -> [Ext || Ext <- [RenegotiationInfo, SRP, HashSigns, EcPointFormats, EllipticCurves, ALPN, NextProtocolNegotiation, Sni], Ext =/= undefined]. srp_user(#ssl_options{srp_identity = {UserName, _}}) -> #srp{username = UserName}; srp_user(_) -> undefined. client_ecc_extensions(SupportedECCs) -> CryptoSupport = proplists:get_value(public_keys, crypto:supports()), case proplists:get_bool(ecdh, CryptoSupport) of true -> EcPointFormats = #ec_point_formats{ec_point_format_list = [?ECPOINT_UNCOMPRESSED]}, EllipticCurves = SupportedECCs, {EcPointFormats, EllipticCurves}; _ -> {undefined, undefined} end. server_ecc_extension(_Version, EcPointFormats) -> CryptoSupport = proplists:get_value(public_keys, crypto:supports()), case proplists:get_bool(ecdh, CryptoSupport) of true -> handle_ecc_point_fmt_extension(EcPointFormats); false -> undefined end. handle_ecc_point_fmt_extension(undefined) -> undefined; handle_ecc_point_fmt_extension(_) -> #ec_point_formats{ec_point_format_list = [?ECPOINT_UNCOMPRESSED]}. advertises_ec_ciphers([]) -> false; advertises_ec_ciphers([{ecdh_ecdsa, _,_,_} | _]) -> true; advertises_ec_ciphers([{ecdhe_ecdsa, _,_,_} | _]) -> true; advertises_ec_ciphers([{ecdh_rsa, _,_,_} | _]) -> true; advertises_ec_ciphers([{ecdhe_rsa, _,_,_} | _]) -> true; advertises_ec_ciphers([{ecdh_anon, _,_,_} | _]) -> true; advertises_ec_ciphers([_| Rest]) -> advertises_ec_ciphers(Rest). select_curve(Client, Server) -> select_curve(Client, Server, false). select_curve(#elliptic_curves{elliptic_curve_list = ClientCurves}, #elliptic_curves{elliptic_curve_list = ServerCurves}, ServerOrder) -> case ServerOrder of false -> select_shared_curve(ClientCurves, ServerCurves); true -> select_shared_curve(ServerCurves, ClientCurves) end; select_curve(undefined, _, _) -> %% Client did not send ECC extension use default curve if %% ECC cipher is negotiated {namedCurve, ?secp256r1}. select_shared_curve([], _) -> no_curve; select_shared_curve([Curve | Rest], Curves) -> case lists:member(Curve, Curves) of true -> {namedCurve, Curve}; false -> select_shared_curve(Rest, Curves) end. sni(undefined) -> undefined; sni(disable) -> undefined; sni(Hostname) -> #sni{hostname = Hostname}. %%-------------------------------------------------------------------- %%% Internal functions %%-------------------------------------------------------------------- validation_fun_and_state({Fun, UserState0}, Role, CertDbHandle, CertDbRef, ServerNameIndication, CRLCheck, CRLDbHandle, CertPath) -> {fun(OtpCert, {extension, _} = Extension, {SslState, UserState}) -> case ssl_certificate:validate(OtpCert, Extension, SslState) of {valid, NewSslState} -> {valid, {NewSslState, UserState}}; {fail, Reason} -> apply_user_fun(Fun, OtpCert, Reason, UserState, SslState, CertPath); {unknown, _} -> apply_user_fun(Fun, OtpCert, Extension, UserState, SslState, CertPath) end; (OtpCert, VerifyResult, {SslState, UserState}) -> apply_user_fun(Fun, OtpCert, VerifyResult, UserState, SslState, CertPath) end, {{Role, CertDbHandle, CertDbRef, ServerNameIndication, CRLCheck, CRLDbHandle}, UserState0}}; validation_fun_and_state(undefined, Role, CertDbHandle, CertDbRef, ServerNameIndication, CRLCheck, CRLDbHandle, CertPath) -> {fun(OtpCert, {extension, _} = Extension, SslState) -> ssl_certificate:validate(OtpCert, Extension, SslState); (OtpCert, VerifyResult, SslState) when (VerifyResult == valid) or (VerifyResult == valid_peer) -> case crl_check(OtpCert, CRLCheck, CertDbHandle, CertDbRef, CRLDbHandle, VerifyResult, CertPath) of valid -> ssl_certificate:validate(OtpCert, VerifyResult, SslState); Reason -> {fail, Reason} end; (OtpCert, VerifyResult, SslState) -> ssl_certificate:validate(OtpCert, VerifyResult, SslState) end, {Role, CertDbHandle, CertDbRef, ServerNameIndication, CRLCheck, CRLDbHandle}}. apply_user_fun(Fun, OtpCert, VerifyResult, UserState0, {_, CertDbHandle, CertDbRef, _, CRLCheck, CRLDbHandle} = SslState, CertPath) when (VerifyResult == valid) or (VerifyResult == valid_peer) -> case Fun(OtpCert, VerifyResult, UserState0) of {Valid, UserState} when (Valid == valid) or (Valid == valid_peer) -> case crl_check(OtpCert, CRLCheck, CertDbHandle, CertDbRef, CRLDbHandle, VerifyResult, CertPath) of valid -> {Valid, {SslState, UserState}}; Result -> apply_user_fun(Fun, OtpCert, Result, UserState, SslState, CertPath) end; {fail, _} = Fail -> Fail end; apply_user_fun(Fun, OtpCert, ExtensionOrError, UserState0, SslState, _CertPath) -> case Fun(OtpCert, ExtensionOrError, UserState0) of {Valid, UserState} when (Valid == valid) or (Valid == valid_peer)-> {Valid, {SslState, UserState}}; {fail, _} = Fail -> Fail; {unknown, UserState} -> {unknown, {SslState, UserState}} end. path_validation_alert({bad_cert, cert_expired}) -> ?ALERT_REC(?FATAL, ?CERTIFICATE_EXPIRED); path_validation_alert({bad_cert, invalid_issuer}) -> ?ALERT_REC(?FATAL, ?BAD_CERTIFICATE); path_validation_alert({bad_cert, invalid_signature}) -> ?ALERT_REC(?FATAL, ?BAD_CERTIFICATE); path_validation_alert({bad_cert, name_not_permitted}) -> ?ALERT_REC(?FATAL, ?BAD_CERTIFICATE); path_validation_alert({bad_cert, unknown_critical_extension}) -> ?ALERT_REC(?FATAL, ?UNSUPPORTED_CERTIFICATE); path_validation_alert({bad_cert, {revoked, _}}) -> ?ALERT_REC(?FATAL, ?CERTIFICATE_REVOKED); %%path_validation_alert({bad_cert, revocation_status_undetermined}) -> %% ?ALERT_REC(?FATAL, ?BAD_CERTIFICATE); path_validation_alert({bad_cert, {revocation_status_undetermined, Details}}) -> Alert = ?ALERT_REC(?FATAL, ?BAD_CERTIFICATE), Alert#alert{reason = Details}; path_validation_alert({bad_cert, selfsigned_peer}) -> ?ALERT_REC(?FATAL, ?BAD_CERTIFICATE); path_validation_alert({bad_cert, unknown_ca}) -> ?ALERT_REC(?FATAL, ?UNKNOWN_CA); path_validation_alert(Reason) -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, Reason). encrypted_premaster_secret(Secret, RSAPublicKey) -> try PreMasterSecret = public_key:encrypt_public(Secret, RSAPublicKey, [{rsa_pad, rsa_pkcs1_padding}]), #encrypted_premaster_secret{premaster_secret = PreMasterSecret} catch _:_-> throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, premaster_encryption_failed)) end. digitally_signed(Version, Hashes, HashAlgo, PrivateKey) -> try do_digitally_signed(Version, Hashes, HashAlgo, PrivateKey) of Signature -> Signature catch error:badkey-> throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, bad_key(PrivateKey))) end. do_digitally_signed({3, Minor}, Hash, HashAlgo, #{algorithm := Alg} = Engine) when Minor >= 3 -> crypto:sign(Alg, HashAlgo, {digest, Hash}, maps:remove(algorithm, Engine)); do_digitally_signed({3, Minor}, Hash, HashAlgo, Key) when Minor >= 3 -> public_key:sign({digest, Hash}, HashAlgo, Key); do_digitally_signed(_Version, Hash, _HashAlgo, #'RSAPrivateKey'{} = Key) -> public_key:encrypt_private(Hash, Key, [{rsa_pad, rsa_pkcs1_padding}]); do_digitally_signed({3, _}, Hash, _, #{algorithm := rsa} = Engine) -> crypto:private_encrypt(rsa, Hash, maps:remove(algorithm, Engine), rsa_pkcs1_padding); do_digitally_signed({3, _}, Hash, HashAlgo, #{algorithm := Alg} = Engine) -> crypto:sign(Alg, HashAlgo, {digest, Hash}, maps:remove(algorithm, Engine)); do_digitally_signed(_Version, Hash, HashAlgo, Key) -> public_key:sign({digest, Hash}, HashAlgo, Key). calc_certificate_verify({3, 0}, HashAlgo, MasterSecret, Handshake) -> ssl_v3:certificate_verify(HashAlgo, MasterSecret, lists:reverse(Handshake)); calc_certificate_verify({3, N}, HashAlgo, _MasterSecret, Handshake) -> tls_v1:certificate_verify(HashAlgo, N, lists:reverse(Handshake)). calc_finished({3, 0}, Role, _PrfAlgo, MasterSecret, Handshake) -> ssl_v3:finished(Role, MasterSecret, lists:reverse(Handshake)); calc_finished({3, N}, Role, PrfAlgo, MasterSecret, Handshake) -> tls_v1:finished(Role, N, PrfAlgo, MasterSecret, lists:reverse(Handshake)). master_secret(Version, MasterSecret, #security_parameters{ bulk_cipher_algorithm = BCA, client_random = ClientRandom, server_random = ServerRandom, hash_size = HashSize, prf_algorithm = PrfAlgo, key_material_length = KML, expanded_key_material_length = EKML, iv_size = IVS}, ConnectionStates, Role) -> {ClientWriteMacSecret, ServerWriteMacSecret, ClientWriteKey, ServerWriteKey, ClientIV, ServerIV} = setup_keys(Version, PrfAlgo, MasterSecret, ServerRandom, ClientRandom, HashSize, KML, EKML, IVS), ConnStates1 = ssl_record:set_master_secret(MasterSecret, ConnectionStates), ConnStates2 = ssl_record:set_mac_secret(ClientWriteMacSecret, ServerWriteMacSecret, Role, ConnStates1), ClientCipherState = ssl_cipher:cipher_init(BCA, ClientIV, ClientWriteKey), ServerCipherState = ssl_cipher:cipher_init(BCA, ServerIV, ServerWriteKey), {MasterSecret, ssl_record:set_pending_cipher_state(ConnStates2, ClientCipherState, ServerCipherState, Role)}. setup_keys({3,0}, _PrfAlgo, MasterSecret, ServerRandom, ClientRandom, HashSize, KML, EKML, IVS) -> ssl_v3:setup_keys(MasterSecret, ServerRandom, ClientRandom, HashSize, KML, EKML, IVS); setup_keys({3,N}, PrfAlgo, MasterSecret, ServerRandom, ClientRandom, HashSize, KML, _EKML, IVS) -> tls_v1:setup_keys(N, PrfAlgo, MasterSecret, ServerRandom, ClientRandom, HashSize, KML, IVS). calc_master_secret({3,0}, _PrfAlgo, PremasterSecret, ClientRandom, ServerRandom) -> ssl_v3:master_secret(PremasterSecret, ClientRandom, ServerRandom); calc_master_secret({3,_}, PrfAlgo, PremasterSecret, ClientRandom, ServerRandom) -> tls_v1:master_secret(PrfAlgo, PremasterSecret, ClientRandom, ServerRandom). handle_renegotiation_extension(Role, RecordCB, Version, Info, Random, NegotiatedCipherSuite, ClientCipherSuites, Compression, ConnectionStates0, Renegotiation, SecureRenegotation) -> case handle_renegotiation_info(RecordCB, Role, Info, ConnectionStates0, Renegotiation, SecureRenegotation, ClientCipherSuites) of {ok, ConnectionStates} -> hello_pending_connection_states(RecordCB, Role, Version, NegotiatedCipherSuite, Random, Compression, ConnectionStates); #alert{} = Alert -> throw(Alert) end. %% Update pending connection states with parameters exchanged via %% hello messages %% NOTE : Role is the role of the receiver of the hello message %% currently being processed. hello_pending_connection_states(_RecordCB, Role, Version, CipherSuite, Random, Compression, ConnectionStates) -> ReadState = ssl_record:pending_connection_state(ConnectionStates, read), WriteState = ssl_record:pending_connection_state(ConnectionStates, write), NewReadSecParams = hello_security_parameters(Role, Version, ReadState, CipherSuite, Random, Compression), NewWriteSecParams = hello_security_parameters(Role, Version, WriteState, CipherSuite, Random, Compression), ssl_record:set_security_params(NewReadSecParams, NewWriteSecParams, ConnectionStates). hello_security_parameters(client, Version, #{security_parameters := SecParams}, CipherSuite, Random, Compression) -> NewSecParams = ssl_cipher:security_parameters(Version, CipherSuite, SecParams), NewSecParams#security_parameters{ server_random = Random, compression_algorithm = Compression }; hello_security_parameters(server, Version, #{security_parameters := SecParams}, CipherSuite, Random, Compression) -> NewSecParams = ssl_cipher:security_parameters(Version, CipherSuite, SecParams), NewSecParams#security_parameters{ client_random = Random, compression_algorithm = Compression }. %%-------------Encode/Decode -------------------------------- encode_server_key(#server_dh_params{dh_p = P, dh_g = G, dh_y = Y}) -> PLen = byte_size(P), GLen = byte_size(G), YLen = byte_size(Y), <>; encode_server_key(#server_ecdh_params{curve = {namedCurve, ECCurve}, public = ECPubKey}) -> %%TODO: support arbitrary keys KLen = size(ECPubKey), <>; encode_server_key(#server_psk_params{hint = PskIdentityHint}) -> Len = byte_size(PskIdentityHint), <>; encode_server_key(Params = #server_dhe_psk_params{hint = undefined}) -> encode_server_key(Params#server_dhe_psk_params{hint = <<>>}); encode_server_key(#server_dhe_psk_params{ hint = PskIdentityHint, dh_params = #server_dh_params{dh_p = P, dh_g = G, dh_y = Y}}) -> Len = byte_size(PskIdentityHint), PLen = byte_size(P), GLen = byte_size(G), YLen = byte_size(Y), <>; encode_server_key(#server_srp_params{srp_n = N, srp_g = G, srp_s = S, srp_b = B}) -> NLen = byte_size(N), GLen = byte_size(G), SLen = byte_size(S), BLen = byte_size(B), <>. encode_client_key(#encrypted_premaster_secret{premaster_secret = PKEPMS},{3, 0}) -> PKEPMS; encode_client_key(#encrypted_premaster_secret{premaster_secret = PKEPMS}, _) -> PKEPMSLen = byte_size(PKEPMS), <>; encode_client_key(#client_diffie_hellman_public{dh_public = DHPublic}, _) -> Len = byte_size(DHPublic), <>; encode_client_key(#client_ec_diffie_hellman_public{dh_public = DHPublic}, _) -> Len = byte_size(DHPublic), <>; encode_client_key(#client_psk_identity{identity = undefined}, _) -> Id = <<"psk_identity">>, Len = byte_size(Id), <>; encode_client_key(#client_psk_identity{identity = Id}, _) -> Len = byte_size(Id), <>; encode_client_key(Identity = #client_dhe_psk_identity{identity = undefined}, Version) -> encode_client_key(Identity#client_dhe_psk_identity{identity = <<"psk_identity">>}, Version); encode_client_key(#client_dhe_psk_identity{identity = Id, dh_public = DHPublic}, _) -> Len = byte_size(Id), DHLen = byte_size(DHPublic), <>; encode_client_key(Identity = #client_rsa_psk_identity{identity = undefined}, Version) -> encode_client_key(Identity#client_rsa_psk_identity{identity = <<"psk_identity">>}, Version); encode_client_key(#client_rsa_psk_identity{identity = Id, exchange_keys = ExchangeKeys}, Version) -> EncPMS = encode_client_key(ExchangeKeys, Version), Len = byte_size(Id), <>; encode_client_key(#client_srp_public{srp_a = A}, _) -> Len = byte_size(A), <>. enc_sign({_, anon}, _Sign, _Version) -> <<>>; enc_sign({HashAlg, SignAlg}, Signature, _Version = {Major, Minor}) when Major == 3, Minor >= 3-> SignLen = byte_size(Signature), HashSign = enc_hashsign(HashAlg, SignAlg), <>; enc_sign(_HashSign, Sign, _Version) -> SignLen = byte_size(Sign), <>. enc_hashsign(HashAlgo, SignAlgo) -> Hash = ssl_cipher:hash_algorithm(HashAlgo), Sign = ssl_cipher:sign_algorithm(SignAlgo), <>. encode_protocol(Protocol, Acc) -> Len = byte_size(Protocol), <>. dec_client_key(PKEPMS, ?KEY_EXCHANGE_RSA, {3, 0}) -> #encrypted_premaster_secret{premaster_secret = PKEPMS}; dec_client_key(<>, ?KEY_EXCHANGE_RSA, _) -> #encrypted_premaster_secret{premaster_secret = PKEPMS}; dec_client_key(<<>>, ?KEY_EXCHANGE_DIFFIE_HELLMAN, _) -> throw(?ALERT_REC(?FATAL, ?UNSUPPORTED_CERTIFICATE, empty_dh_public)); dec_client_key(<>, ?KEY_EXCHANGE_DIFFIE_HELLMAN, _) -> #client_diffie_hellman_public{dh_public = DH_Y}; dec_client_key(<<>>, ?KEY_EXCHANGE_EC_DIFFIE_HELLMAN, _) -> throw(?ALERT_REC(?FATAL, ?UNSUPPORTED_CERTIFICATE, empty_dh_public)); dec_client_key(<>, ?KEY_EXCHANGE_EC_DIFFIE_HELLMAN, _) -> #client_ec_diffie_hellman_public{dh_public = DH_Y}; dec_client_key(<>, ?KEY_EXCHANGE_PSK, _) -> #client_psk_identity{identity = Id}; dec_client_key(<>, ?KEY_EXCHANGE_DHE_PSK, _) -> #client_dhe_psk_identity{identity = Id, dh_public = DH_Y}; dec_client_key(<>, ?KEY_EXCHANGE_RSA_PSK, {3, 0}) -> #client_rsa_psk_identity{identity = Id, exchange_keys = #encrypted_premaster_secret{premaster_secret = PKEPMS}}; dec_client_key(<>, ?KEY_EXCHANGE_RSA_PSK, _) -> #client_rsa_psk_identity{identity = Id, exchange_keys = #encrypted_premaster_secret{premaster_secret = PKEPMS}}; dec_client_key(<>, ?KEY_EXCHANGE_SRP, _) -> #client_srp_public{srp_a = A}. dec_server_key_params(Len, Keys, Version) -> <> = Keys, dec_server_key_signature(Params, Signature, Version). dec_server_key_signature(Params, <>, {Major, Minor}) when Major == 3, Minor >= 3 -> HashSign = {ssl_cipher:hash_algorithm(HashAlgo), ssl_cipher:sign_algorithm(SignAlgo)}, {Params, HashSign, <<>>}; dec_server_key_signature(Params, <>, {Major, Minor}) when Major == 3, Minor >= 3 -> HashSign = {ssl_cipher:hash_algorithm(HashAlgo), ssl_cipher:sign_algorithm(SignAlgo)}, {Params, HashSign, Signature}; dec_server_key_signature(Params, <<>>, _) -> {Params, {null, anon}, <<>>}; dec_server_key_signature(Params, <>, _) -> {Params, {null, anon}, <<>>}; dec_server_key_signature(Params, <>, _) -> {Params, undefined, Signature}; dec_server_key_signature(_, _, _) -> throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, failed_to_decrypt_server_key_sign)). dec_hello_extensions(<<>>, Acc) -> Acc; dec_hello_extensions(<>, Acc) when Len + 2 =:= ExtLen -> ALPN = #alpn{extension_data = ExtensionData}, dec_hello_extensions(Rest, Acc#hello_extensions{alpn = ALPN}); dec_hello_extensions(<>, Acc) -> NextP = #next_protocol_negotiation{extension_data = ExtensionData}, dec_hello_extensions(Rest, Acc#hello_extensions{next_protocol_negotiation = NextP}); dec_hello_extensions(<>, Acc) -> RenegotiateInfo = case Len of 1 -> % Initial handshake Info; % should be <<0>> will be matched in handle_renegotiation_info _ -> VerifyLen = Len - 1, <> = Info, VerifyInfo end, dec_hello_extensions(Rest, Acc#hello_extensions{renegotiation_info = #renegotiation_info{renegotiated_connection = RenegotiateInfo}}); dec_hello_extensions(<>, Acc) when Len == SRPLen + 2 -> dec_hello_extensions(Rest, Acc#hello_extensions{srp = #srp{username = SRP}}); dec_hello_extensions(<>, Acc) -> SignAlgoListLen = Len - 2, <> = ExtData, HashSignAlgos = [{ssl_cipher:hash_algorithm(Hash), ssl_cipher:sign_algorithm(Sign)} || <> <= SignAlgoList], dec_hello_extensions(Rest, Acc#hello_extensions{signature_algs = #hash_sign_algos{hash_sign_algos = HashSignAlgos}}); dec_hello_extensions(<>, Acc) -> <> = ExtData, %% Ignore unknown curves Pick = fun(Enum) -> case tls_v1:enum_to_oid(Enum) of undefined -> false; Oid -> {true, Oid} end end, EllipticCurves = lists:filtermap(Pick, [ECC || <> <= EllipticCurveList]), dec_hello_extensions(Rest, Acc#hello_extensions{elliptic_curves = #elliptic_curves{elliptic_curve_list = EllipticCurves}}); dec_hello_extensions(<>, Acc) -> <> = ExtData, ECPointFormats = binary_to_list(ECPointFormatList), dec_hello_extensions(Rest, Acc#hello_extensions{ec_point_formats = #ec_point_formats{ec_point_format_list = ECPointFormats}}); dec_hello_extensions(<>, Acc) when Len == 0 -> dec_hello_extensions(Rest, Acc#hello_extensions{sni = ""}); %% Server may send an empy SNI dec_hello_extensions(<>, Acc) -> <> = ExtData, dec_hello_extensions(Rest, Acc#hello_extensions{sni = dec_sni(NameList)}); %% Ignore data following the ClientHello (i.e., %% extensions) if not understood. dec_hello_extensions(<>, Acc) -> dec_hello_extensions(Rest, Acc); %% This theoretically should not happen if the protocol is followed, but if it does it is ignored. dec_hello_extensions(_, Acc) -> Acc. dec_hashsign(<>) -> {ssl_cipher:hash_algorithm(HashAlgo), ssl_cipher:sign_algorithm(SignAlgo)}. %% Ignore unknown names (only host_name is supported) dec_sni(<>) -> #sni{hostname = binary_to_list(HostName)}; dec_sni(<>) -> dec_sni(Rest); dec_sni(_) -> undefined. decode_next_protocols({next_protocol_negotiation, Protocols}) -> decode_protocols(Protocols, []). decode_protocols(<<>>, Acc) -> lists:reverse(Acc); decode_protocols(<>, Acc) -> case Len of 0 -> {error, invalid_protocols}; _ -> decode_protocols(Rest, [Protocol|Acc]) end; decode_protocols(_Bytes, _Acc) -> {error, invalid_protocols}. %% encode/decode stream of certificate data to/from list of certificate data certs_to_list(ASN1Certs) -> certs_to_list(ASN1Certs, []). certs_to_list(<>, Acc) -> certs_to_list(Rest, [Cert | Acc]); certs_to_list(<<>>, Acc) -> lists:reverse(Acc, []). certs_from_list(ACList) -> list_to_binary([begin CertLen = byte_size(Cert), <> end || Cert <- ACList]). from_3bytes(Bin3) -> from_3bytes(Bin3, []). from_3bytes(<<>>, Acc) -> lists:reverse(Acc); from_3bytes(<>, Acc) -> from_3bytes(Rest, [?uint16(N) | Acc]). from_2bytes(Bin2) -> from_2bytes(Bin2, []). from_2bytes(<<>>, Acc) -> lists:reverse(Acc); from_2bytes(<>, Acc) -> from_2bytes(Rest, [?uint16(N) | Acc]). key_exchange_alg(rsa) -> ?KEY_EXCHANGE_RSA; key_exchange_alg(Alg) when Alg == dhe_rsa; Alg == dhe_dss; Alg == dh_dss; Alg == dh_rsa; Alg == dh_anon -> ?KEY_EXCHANGE_DIFFIE_HELLMAN; key_exchange_alg(Alg) when Alg == ecdhe_rsa; Alg == ecdh_rsa; Alg == ecdhe_ecdsa; Alg == ecdh_ecdsa; Alg == ecdh_anon -> ?KEY_EXCHANGE_EC_DIFFIE_HELLMAN; key_exchange_alg(psk) -> ?KEY_EXCHANGE_PSK; key_exchange_alg(dhe_psk) -> ?KEY_EXCHANGE_DHE_PSK; key_exchange_alg(rsa_psk) -> ?KEY_EXCHANGE_RSA_PSK; key_exchange_alg(Alg) when Alg == srp_rsa; Alg == srp_dss; Alg == srp_anon -> ?KEY_EXCHANGE_SRP; key_exchange_alg(_) -> ?NULL. %%-------------Extension handling -------------------------------- %% Receive protocols, choose one from the list, return it. handle_alpn_extension(_, {error, Reason}) -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, Reason); handle_alpn_extension([], _) -> ?ALERT_REC(?FATAL, ?NO_APPLICATION_PROTOCOL); handle_alpn_extension([ServerProtocol|Tail], ClientProtocols) -> case lists:member(ServerProtocol, ClientProtocols) of true -> ServerProtocol; false -> handle_alpn_extension(Tail, ClientProtocols) end. handle_next_protocol(undefined, _NextProtocolSelector, _Renegotiating) -> undefined; handle_next_protocol(#next_protocol_negotiation{} = NextProtocols, NextProtocolSelector, Renegotiating) -> case next_protocol_extension_allowed(NextProtocolSelector, Renegotiating) of true -> select_next_protocol(decode_next_protocols(NextProtocols), NextProtocolSelector); false -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, unexpected_next_protocol_extension) end. handle_next_protocol_extension(NextProtocolNegotiation, Renegotiation, SslOpts)-> case handle_next_protocol_on_server(NextProtocolNegotiation, Renegotiation, SslOpts) of #alert{} = Alert -> Alert; ProtocolsToAdvertise -> ProtocolsToAdvertise end. handle_next_protocol_on_server(undefined, _Renegotiation, _SslOpts) -> undefined; handle_next_protocol_on_server(#next_protocol_negotiation{extension_data = <<>>}, false, #ssl_options{next_protocols_advertised = Protocols}) -> Protocols; handle_next_protocol_on_server(_Hello, _Renegotiation, _SSLOpts) -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, unexpected_next_protocol_extension). next_protocol_extension_allowed(NextProtocolSelector, Renegotiating) -> NextProtocolSelector =/= undefined andalso not Renegotiating. select_next_protocol({error, Reason}, _NextProtocolSelector) -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, Reason); select_next_protocol(Protocols, NextProtocolSelector) -> case NextProtocolSelector(Protocols) of ?NO_PROTOCOL -> ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE, no_next_protocol); Protocol when is_binary(Protocol) -> Protocol end. handle_srp_extension(undefined, Session) -> Session; handle_srp_extension(#srp{username = Username}, Session) -> Session#session{srp_username = Username}. %%-------------Misc -------------------------------- select_cipher_suite(CipherSuites, Suites, false) -> select_cipher_suite(CipherSuites, Suites); select_cipher_suite(CipherSuites, Suites, true) -> select_cipher_suite(Suites, CipherSuites). select_cipher_suite([], _) -> no_suite; select_cipher_suite([Suite | ClientSuites], SupportedSuites) -> case is_member(Suite, SupportedSuites) of true -> Suite; false -> select_cipher_suite(ClientSuites, SupportedSuites) end. int_to_bin(I) -> L = (length(integer_to_list(I, 16)) + 1) div 2, <>. is_member(Suite, SupportedSuites) -> lists:member(Suite, SupportedSuites). select_compression(_CompressionMetodes) -> ?NULL. available_signature_algs(undefined, _) -> undefined; available_signature_algs(SupportedHashSigns, Version) when Version >= {3, 3} -> #hash_sign_algos{hash_sign_algos = SupportedHashSigns}; available_signature_algs(_, _) -> undefined. psk_secret(PSKIdentity, PSKLookup) -> case handle_psk_identity(PSKIdentity, PSKLookup) of {ok, PSK} when is_binary(PSK) -> Len = erlang:byte_size(PSK), <>; #alert{} = Alert -> Alert; _ -> throw(?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER)) end. psk_secret(PSKIdentity, PSKLookup, PremasterSecret) -> case handle_psk_identity(PSKIdentity, PSKLookup) of {ok, PSK} when is_binary(PSK) -> Len = erlang:byte_size(PremasterSecret), PSKLen = erlang:byte_size(PSK), <>; #alert{} = Alert -> Alert; _ -> throw(?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER)) end. handle_psk_identity(_PSKIdentity, LookupFun) when LookupFun == undefined -> error; handle_psk_identity(PSKIdentity, {Fun, UserState}) -> Fun(psk, PSKIdentity, UserState). crl_check(_, false, _,_,_, _, _) -> valid; crl_check(_, peer, _, _,_, valid, _) -> %% Do not check CAs with this option. valid; crl_check(OtpCert, Check, CertDbHandle, CertDbRef, {Callback, CRLDbHandle}, _, CertPath) -> Options = [{issuer_fun, {fun(_DP, CRL, Issuer, DBInfo) -> ssl_crl:trusted_cert_and_path(CRL, Issuer, {CertPath, DBInfo}) end, {CertDbHandle, CertDbRef}}}, {update_crl, fun(DP, CRL) -> Callback:fresh_crl(DP, CRL) end}, {undetermined_details, true} ], case dps_and_crls(OtpCert, Callback, CRLDbHandle, ext) of no_dps -> crl_check_same_issuer(OtpCert, Check, dps_and_crls(OtpCert, Callback, CRLDbHandle, same_issuer), Options); DpsAndCRLs -> %% This DP list may be empty if relevant CRLs existed %% but could not be retrived, will result in {bad_cert, revocation_status_undetermined} case public_key:pkix_crls_validate(OtpCert, DpsAndCRLs, Options) of {bad_cert, {revocation_status_undetermined, _}} -> crl_check_same_issuer(OtpCert, Check, dps_and_crls(OtpCert, Callback, CRLDbHandle, same_issuer), Options); Other -> Other end end. crl_check_same_issuer(OtpCert, best_effort, Dps, Options) -> case public_key:pkix_crls_validate(OtpCert, Dps, Options) of {bad_cert, {revocation_status_undetermined, _}} -> valid; Other -> Other end; crl_check_same_issuer(OtpCert, _, Dps, Options) -> public_key:pkix_crls_validate(OtpCert, Dps, Options). dps_and_crls(OtpCert, Callback, CRLDbHandle, ext) -> case public_key:pkix_dist_points(OtpCert) of [] -> no_dps; DistPoints -> Issuer = OtpCert#'OTPCertificate'.tbsCertificate#'OTPTBSCertificate'.issuer, CRLs = distpoints_lookup(DistPoints, Issuer, Callback, CRLDbHandle), dps_and_crls(DistPoints, CRLs, []) end; dps_and_crls(OtpCert, Callback, CRLDbHandle, same_issuer) -> DP = #'DistributionPoint'{distributionPoint = {fullName, GenNames}} = public_key:pkix_dist_point(OtpCert), CRLs = lists:flatmap(fun({directoryName, Issuer}) -> Callback:select(Issuer, CRLDbHandle); (_) -> [] end, GenNames), [{DP, {CRL, public_key:der_decode('CertificateList', CRL)}} || CRL <- CRLs]. dps_and_crls([], _, Acc) -> Acc; dps_and_crls([DP | Rest], CRLs, Acc) -> DpCRL = [{DP, {CRL, public_key:der_decode('CertificateList', CRL)}} || CRL <- CRLs], dps_and_crls(Rest, CRLs, DpCRL ++ Acc). distpoints_lookup([],_, _, _) -> []; distpoints_lookup([DistPoint | Rest], Issuer, Callback, CRLDbHandle) -> Result = try Callback:lookup(DistPoint, Issuer, CRLDbHandle) catch error:undef -> %% The callback module still uses the 2-argument %% version of the lookup function. Callback:lookup(DistPoint, CRLDbHandle) end, case Result of not_available -> distpoints_lookup(Rest, Issuer, Callback, CRLDbHandle); CRLs -> CRLs end. sign_algo(?rsaEncryption) -> rsa; sign_algo(?'id-ecPublicKey') -> ecdsa; sign_algo(?'id-dsa') -> dsa; sign_algo(Alg) -> {_, Sign} =public_key:pkix_sign_types(Alg), Sign. is_acceptable_hash_sign(Algos, _, _, KeyExAlgo, SupportedHashSigns) when KeyExAlgo == dh_dss; KeyExAlgo == dh_rsa; KeyExAlgo == dh_ecdsa -> %% dh_* could be called only dh in TLS-1.2 is_acceptable_hash_sign(Algos, SupportedHashSigns); is_acceptable_hash_sign(Algos, rsa, ecdsa, ecdh_rsa, SupportedHashSigns) -> is_acceptable_hash_sign(Algos, SupportedHashSigns); is_acceptable_hash_sign({_, rsa} = Algos, rsa, _, dhe_rsa, SupportedHashSigns) -> is_acceptable_hash_sign(Algos, SupportedHashSigns); is_acceptable_hash_sign({_, rsa} = Algos, rsa, rsa, ecdhe_rsa, SupportedHashSigns) -> is_acceptable_hash_sign(Algos, SupportedHashSigns); is_acceptable_hash_sign({_, rsa} = Algos, rsa, rsa, rsa, SupportedHashSigns) -> is_acceptable_hash_sign(Algos, SupportedHashSigns); is_acceptable_hash_sign({_, rsa} = Algos, rsa, _, srp_rsa, SupportedHashSigns) -> is_acceptable_hash_sign(Algos, SupportedHashSigns); is_acceptable_hash_sign({_, rsa} = Algos, rsa, _, rsa_psk, SupportedHashSigns) -> is_acceptable_hash_sign(Algos, SupportedHashSigns); is_acceptable_hash_sign({_, dsa} = Algos, dsa, _, dhe_dss, SupportedHashSigns) -> is_acceptable_hash_sign(Algos, SupportedHashSigns); is_acceptable_hash_sign({_, dsa} = Algos, dsa, _, srp_dss, SupportedHashSigns) -> is_acceptable_hash_sign(Algos, SupportedHashSigns); is_acceptable_hash_sign({_, ecdsa} = Algos, ecdsa, _, dhe_ecdsa, SupportedHashSigns) -> is_acceptable_hash_sign(Algos, SupportedHashSigns); is_acceptable_hash_sign({_, ecdsa} = Algos, ecdsa, ecdsa, ecdh_ecdsa, SupportedHashSigns) -> is_acceptable_hash_sign(Algos, SupportedHashSigns); is_acceptable_hash_sign({_, ecdsa} = Algos, ecdsa, ecdsa, ecdhe_ecdsa, SupportedHashSigns) -> is_acceptable_hash_sign(Algos, SupportedHashSigns); is_acceptable_hash_sign(_, _, _, KeyExAlgo, _) when KeyExAlgo == psk; KeyExAlgo == dhe_psk; KeyExAlgo == srp_anon; KeyExAlgo == dh_anon; KeyExAlgo == ecdhe_anon -> true; is_acceptable_hash_sign(_,_, _,_,_) -> false. is_acceptable_hash_sign(Algos, SupportedHashSigns) -> lists:member(Algos, SupportedHashSigns). is_acceptable_cert_type(Sign, _HashSigns, Types) -> lists:member(sign_type(Sign), binary_to_list(Types)). is_supported_sign(Sign, HashSigns) -> [] =/= lists:dropwhile(fun({_, S}) when S =/= Sign -> true; (_)-> false end, HashSigns). sign_type(rsa) -> ?RSA_SIGN; sign_type(dsa) -> ?DSS_SIGN; sign_type(ecdsa) -> ?ECDSA_SIGN. bad_key(#'DSAPrivateKey'{}) -> unacceptable_dsa_key; bad_key(#'RSAPrivateKey'{}) -> unacceptable_rsa_key; bad_key(#'ECPrivateKey'{}) -> unacceptable_ecdsa_key. available_signature_algs(undefined, SupportedHashSigns, _, Version) when Version >= {3,3} -> SupportedHashSigns; available_signature_algs(#hash_sign_algos{hash_sign_algos = ClientHashSigns}, SupportedHashSigns, _, Version) when Version >= {3,3} -> sets:to_list(sets:intersection(sets:from_list(ClientHashSigns), sets:from_list(SupportedHashSigns))); available_signature_algs(_, _, _, _) -> undefined. server_name(_, _, server) -> undefined; %% Not interesting to check your own name. server_name(undefined, Host, client) -> {fallback, Host}; %% Fallback to Host argument to connect server_name(SNI, _, client) -> SNI. %% If Server Name Indication is available