diff options
Diffstat (limited to 'lib/ssl/src/tls_handshake_1_3.erl')
| -rw-r--r-- | lib/ssl/src/tls_handshake_1_3.erl | 165 |
1 files changed, 113 insertions, 52 deletions
diff --git a/lib/ssl/src/tls_handshake_1_3.erl b/lib/ssl/src/tls_handshake_1_3.erl index 8c302d8d57..cbe9550e70 100644 --- a/lib/ssl/src/tls_handshake_1_3.erl +++ b/lib/ssl/src/tls_handshake_1_3.erl @@ -39,6 +39,7 @@ %% Create handshake messages -export([certificate/5, + certificate_verify/5, server_hello/4]). %%==================================================================== @@ -78,6 +79,23 @@ certificate(OwnCert, CertDbHandle, CertDbRef, _CRContext, server) -> ?ALERT_REC(?FATAL, ?INTERNAL_ERROR, {server_has_no_suitable_certificates, Error}) end. +%% TODO: use maybe monad for error handling! +certificate_verify(OwnCert, PrivateKey, SignatureScheme, Messages, server) -> + {HashAlgo, _, _} = + ssl_cipher:scheme_to_components(SignatureScheme), + + %% Transcript-Hash(Handshake Context, Certificate) + Context = [Messages, OwnCert], + THash = tls_v1:transcript_hash(Context, HashAlgo), + + Signature = digitally_sign(THash, <<"TLS 1.3, server CertificateVerify">>, + HashAlgo, PrivateKey), + + #certificate_verify_1_3{ + algorithm = SignatureScheme, + signature = Signature + }. + %%==================================================================== %% Encode handshake %%==================================================================== @@ -223,6 +241,38 @@ certificate_entry(DER) -> extensions = #{} %% Extensions not supported. }. +%% The digital signature is then computed over the concatenation of: +%% - A string that consists of octet 32 (0x20) repeated 64 times +%% - The context string +%% - A single 0 byte which serves as the separator +%% - The content to be signed +%% +%% For example, if the transcript hash was 32 bytes of 01 (this length +%% would make sense for SHA-256), the content covered by the digital +%% signature for a server CertificateVerify would be: +%% +%% 2020202020202020202020202020202020202020202020202020202020202020 +%% 2020202020202020202020202020202020202020202020202020202020202020 +%% 544c5320312e332c207365727665722043657274696669636174655665726966 +%% 79 +%% 00 +%% 0101010101010101010101010101010101010101010101010101010101010101 +digitally_sign(THash, Context, HashAlgo, PrivateKey = #'RSAPrivateKey'{}) -> + Content = build_content(Context, THash), + + %% The length of the Salt MUST be equal to the length of the output + %% of the digest algorithm. + PadLen = ssl_cipher:hash_size(HashAlgo), + + public_key:sign(Content, HashAlgo, PrivateKey, + [{rsa_padding, rsa_pkcs1_pss_padding}, + {rsa_pss_saltlen, PadLen}]). + + +build_content(Context, THash) -> + <<" ", + " ", + Context/binary,?BYTE(0),THash/binary>>. %%==================================================================== %% Handle handshake messages @@ -263,15 +313,15 @@ handle_client_hello(#client_hello{cipher_suites = ClientCiphers, Cipher = Maybe(select_cipher_suite(ClientCiphers, ServerCiphers)), Group = Maybe(select_server_group(ServerGroups, ClientGroups)), Maybe(validate_key_share(ClientGroups, ClientShares)), + ClientPubKey = Maybe(get_client_public_key(Group, ClientShares)), - %% Handle certificate - {PublicKeyAlgo, SignAlgo} = get_certificate_params(Cert), + {PublicKeyAlgo, SignAlgo, SignHash} = get_certificate_params(Cert), %% Check if client supports signature algorithm of server certificate - Maybe(check_cert_sign_algo(SignAlgo, ClientSignAlgs, ClientSignAlgsCert)), + Maybe(check_cert_sign_algo(SignAlgo, SignHash, ClientSignAlgs, ClientSignAlgsCert)), - %% Check if server supports + %% Select signature algorithm (used in CertificateVerify message). SelectedSignAlg = Maybe(select_sign_algo(PublicKeyAlgo, ClientSignAlgs, ServerSignAlgs)), %% Generate server_share @@ -294,9 +344,9 @@ handle_client_hello(#client_hello{cipher_suites = ClientCiphers, ?ALERT_REC(?FATAL, ?INSUFFICIENT_SECURITY, no_suitable_groups); {Ref, illegal_parameter} -> ?ALERT_REC(?FATAL, ?ILLEGAL_PARAMETER); - {Ref, {client_hello_retry_request, _Group0}} -> + {Ref, {hello_retry_request, _Group0}} -> %% TODO - exit({client_hello_retry_request, not_implemented}); + ?ALERT_REC(?FATAL, ?INTERNAL_ERROR, "hello_retry_request not implemented"); {Ref, no_suitable_cipher} -> ?ALERT_REC(?FATAL, ?INSUFFICIENT_SECURITY, no_suitable_cipher); {Ref, {insufficient_security, no_suitable_signature_algorithm}} -> @@ -353,8 +403,13 @@ get_client_public_key(Group, ClientShares) -> {value, {_, _, ClientPublicKey}} -> {ok, ClientPublicKey}; false -> - %% ClientHelloRetryRequest - {error, {client_hello_retry_request, Group}} + %% 4.1.4. Hello Retry Request + %% + %% The server will send this message in response to a ClientHello + %% message if it is able to find an acceptable set of parameters but the + %% ClientHello does not contain sufficient information to proceed with + %% the handshake. + {error, {hello_retry_request, Group}} end. select_cipher_suite([], _) -> @@ -379,22 +434,28 @@ select_cipher_suite([Cipher|ClientCiphers], ServerCiphers) -> %% If no "signature_algorithms_cert" extension is %% present, then the "signature_algorithms" extension also applies to %% signatures appearing in certificates. -check_cert_sign_algo(SignAlgo, ClientSignAlgs, undefined) -> - maybe_lists_member(SignAlgo, ClientSignAlgs, - {insufficient_security, no_suitable_signature_algorithm}); -check_cert_sign_algo(SignAlgo, _, ClientSignAlgsCert) -> - maybe_lists_member(SignAlgo, ClientSignAlgsCert, - {insufficient_security, no_suitable_signature_algorithm}). + +%% Check if the signature algorithm of the server certificate is supported +%% by the client. +check_cert_sign_algo(SignAlgo, SignHash, ClientSignAlgs, undefined) -> + do_check_cert_sign_algo(SignAlgo, SignHash, ClientSignAlgs); +check_cert_sign_algo(SignAlgo, SignHash, _, ClientSignAlgsCert) -> + do_check_cert_sign_algo(SignAlgo, SignHash, ClientSignAlgsCert). %% DSA keys are not supported by TLS 1.3 select_sign_algo(dsa, _ClientSignAlgs, _ServerSignAlgs) -> {error, {insufficient_security, no_suitable_public_key}}; -%% TODO: Implement check for ellipctic curves! +%% TODO: Implement support for ECDSA keys! +select_sign_algo(_, [], _) -> + {error, {insufficient_security, no_suitable_signature_algorithm}}; select_sign_algo(PublicKeyAlgo, [C|ClientSignAlgs], ServerSignAlgs) -> {_, S, _} = ssl_cipher:scheme_to_components(C), - case PublicKeyAlgo =:= rsa andalso - ((S =:= rsa_pkcs1) orelse (S =:= rsa_pss_rsae) orelse (S =:= rsa_pss_pss)) andalso + %% RSASSA-PKCS1-v1_5 and Legacy algorithms are not defined for use in signed + %% TLS handshake messages: filter sha-1 and rsa_pkcs1. + case ((PublicKeyAlgo =:= rsa andalso S =:= rsa_pss_rsae) + orelse (PublicKeyAlgo =:= rsa_pss andalso S =:= rsa_pss_rsae)) + andalso lists:member(C, ServerSignAlgs) of true -> {ok, C}; @@ -403,51 +464,51 @@ select_sign_algo(PublicKeyAlgo, [C|ClientSignAlgs], ServerSignAlgs) -> end. -maybe_lists_member(Elem, List, Error) -> - case lists:member(Elem, List) of +do_check_cert_sign_algo(_, _, []) -> + {error, {insufficient_security, no_suitable_signature_algorithm}}; +do_check_cert_sign_algo(SignAlgo, SignHash, [Scheme|T]) -> + {Hash, Sign, _Curve} = ssl_cipher:scheme_to_components(Scheme), + case compare_sign_algos(SignAlgo, SignHash, Sign, Hash) of true -> ok; - false -> - {error, Error} + _Else -> + do_check_cert_sign_algo(SignAlgo, SignHash, T) end. -%% TODO: test with ecdsa, rsa_pss_rsae, rsa_pss_pss + +%% id-RSASSA-PSS (rsa_pss) indicates that the key may only be used for PSS signatures. +%% TODO: Uncomment when rsa_pss signatures are supported in certificates +%% compare_sign_algos(rsa_pss, Hash, Algo, Hash) +%% when Algo =:= rsa_pss_pss -> +%% true; +%% rsaEncryption (rsa) allows the key to be used for any of the standard encryption or +%% signature schemes. +compare_sign_algos(rsa, Hash, Algo, Hash) + when Algo =:= rsa_pss_rsae orelse + Algo =:= rsa_pkcs1 -> + true; +compare_sign_algos(Algo, Hash, Algo, Hash) -> + true; +compare_sign_algos(_, _, _, _) -> + false. + + get_certificate_params(Cert) -> {SignAlgo0, _Param, PublicKeyAlgo0} = ssl_handshake:get_cert_params(Cert), - SignAlgo = public_key:pkix_sign_types(SignAlgo0), + {SignHash0, SignAlgo} = public_key:pkix_sign_types(SignAlgo0), + %% Convert hash to new format + SignHash = case SignHash0 of + sha -> + sha1; + H -> H + end, PublicKeyAlgo = public_key_algo(PublicKeyAlgo0), - Scheme = sign_algo_to_scheme(SignAlgo), - {PublicKeyAlgo, Scheme}. - -sign_algo_to_scheme({Hash0, Sign0}) -> - SupportedSchemes = tls_v1:default_signature_schemes({3,4}), - Hash = case Hash0 of - sha -> - sha1; - H -> - H - end, - Sign = case Sign0 of - rsa -> - rsa_pkcs1; - S -> - S - end, - sign_algo_to_scheme(Hash, Sign, SupportedSchemes). -%% -sign_algo_to_scheme(_, _, []) -> - not_found; -sign_algo_to_scheme(H, S, [Scheme|T]) -> - {Hash, Sign, _Curve} = ssl_cipher:scheme_to_components(Scheme), - case H =:= Hash andalso S =:= Sign of - true -> - Scheme; - false -> - sign_algo_to_scheme(H, S, T) - end. + {PublicKeyAlgo, SignAlgo, SignHash}. %% Note: copied from ssl_handshake +public_key_algo(?'id-RSASSA-PSS') -> + rsa_pss; public_key_algo(?rsaEncryption) -> rsa; public_key_algo(?'id-ecPublicKey') -> |