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%%% Copyright (c) 2014-2015, NORDUnet A/S.
%%% See LICENSE for licensing information.
-module(catlfish).
-export([add_chain/3, entries/2, entry_and_proof/2]).
-export([known_roots/0, update_known_roots/0]).
-export([init_cache_table/0]).
-export([entryhash_from_entry/1, verify_entry/1, verify_entry/2]).
-include_lib("eunit/include/eunit.hrl").
-define(PROTOCOL_VERSION, 0).
-type signature_type() :: certificate_timestamp | tree_hash | test. % uint8
-type entry_type() :: x509_entry | precert_entry | test. % uint16
-type leaf_type() :: timestamped_entry | test. % uint8
-type leaf_version() :: v1 | v2. % uint8
-record(mtl, {leaf_version :: leaf_version(),
leaf_type :: leaf_type(),
entry :: timestamped_entry()}).
-type mtl() :: #mtl{}.
-record(timestamped_entry, {timestamp :: integer(),
entry_type :: entry_type(),
signed_entry :: signed_x509_entry() |
signed_precert_entry(),
extensions = <<>> :: binary()}).
-type timestamped_entry() :: #timestamped_entry{}.
-record(signed_x509_entry, {asn1_cert :: binary()}).
-type signed_x509_entry() :: #signed_x509_entry{}.
-record(signed_precert_entry, {issuer_key_hash :: binary(),
tbs_certificate :: binary()}).
-type signed_precert_entry() :: #signed_precert_entry{}.
-spec serialise(mtl() | timestamped_entry() |
signed_x509_entry() | signed_precert_entry()) -> binary().
%% @doc Serialise a MerkleTreeLeaf as per RFC6962 Section 3.4.
serialise(#mtl{leaf_version = LeafVersion,
leaf_type = LeafType,
entry = TimestampedEntry}) ->
list_to_binary(
[serialise_leaf_version(LeafVersion),
serialise_leaf_type(LeafType),
serialise(TimestampedEntry)]);
%% @doc Serialise a TimestampedEntry as per RFC6962 Section 3.4.
serialise(#timestamped_entry{timestamp = Timestamp,
entry_type = EntryType,
signed_entry = SignedEntry,
extensions = Extensions}) ->
list_to_binary(
[<<Timestamp:64>>,
serialise_entry_type(EntryType),
serialise(SignedEntry),
encode_tls_vector(Extensions, 2)]);
%% @doc Serialise an ASN1.Cert as per RFC6962 Section 3.1.
serialise(#signed_x509_entry{asn1_cert = Cert}) ->
encode_tls_vector(Cert, 3);
%% @doc Serialise a PreCert as per RFC6962 Section 3.2.
serialise(#signed_precert_entry{
issuer_key_hash = IssuerKeyHash,
tbs_certificate = TBSCertificate}) when is_binary(IssuerKeyHash),
size(IssuerKeyHash) == 32 ->
list_to_binary(
[IssuerKeyHash,
encode_tls_vector(TBSCertificate, 3)]).
serialise_leaf_version(v1) ->
<<0:8>>;
serialise_leaf_version(v2) ->
<<1:8>>.
deserialise_leaf_version(<<0:8>>) ->
v1;
deserialise_leaf_version(<<1:8>>) ->
v2.
serialise_leaf_type(timestamped_entry) ->
<<0:8>>.
deserialise_leaf_type(<<0:8>>) ->
timestamped_entry.
serialise_entry_type(x509_entry) ->
<<0:16>>;
serialise_entry_type(precert_entry) ->
<<1:16>>.
deserialise_entry_type(<<0:16>>) ->
x509_entry;
deserialise_entry_type(<<1:16>>) ->
precert_entry.
-spec serialise_signature_type(signature_type()) -> binary().
serialise_signature_type(certificate_timestamp) ->
<<0:8>>.
calc_sct(TimestampedEntry) ->
plop:serialise(
plop:spt(list_to_binary([<<?PROTOCOL_VERSION:8>>,
serialise_signature_type(certificate_timestamp),
serialise(TimestampedEntry)]))).
get_sct(Hash, TimestampedEntry) ->
case application:get_env(catlfish, sctcache_root_path) of
{ok, RootPath} ->
case perm:readfile(RootPath, Hash) of
Contents when is_binary(Contents) ->
Contents;
noentry ->
SCT = calc_sct(TimestampedEntry),
ok = perm:ensurefile_nosync(RootPath, Hash, SCT),
SCT
end;
_ ->
calc_sct(TimestampedEntry)
end.
add_to_db(Type, LeafCert, CertChain, EntryHash) ->
EntryType = case Type of
normal -> x509_entry;
precert -> precert_entry
end,
Timestamp = plop:generate_timestamp(),
TSE = timestamped_entry(Timestamp, EntryType, LeafCert, CertChain),
MTLText = serialise(#mtl{leaf_version = v1,
leaf_type = timestamped_entry,
entry = TSE}),
MTLHash = ht:leaf_hash(MTLText),
LogEntry = pack_entry(Type, MTLText, LeafCert, CertChain),
ok = plop:add(LogEntry, MTLHash, EntryHash),
{TSE, MTLHash}.
get_ratelimit_token(Type) ->
ratelimit:get_token(Type).
-spec add_chain(binary(), [binary()], normal|precert) -> {[{_,_},...]}.
add_chain(LeafCert, CertChain, Type) ->
EntryHash = crypto:hash(sha256, [LeafCert | CertChain]),
{TimestampedEntry, Hash} =
case plop:get(EntryHash) of
notfound ->
case get_ratelimit_token(add_chain) of
ok ->
add_to_db(Type, LeafCert, CertChain, EntryHash);
_ ->
exit({internalerror, "Rate limiting"})
end;
{_Index, MTLHash, DBEntry} ->
{_Type, MTLText, _Cert, _Chain} = unpack_entry(DBEntry),
MTL = deserialise_mtl(MTLText),
MTLText = serialise(MTL), % verify FIXME: remove
{MTL#mtl.entry, MTLHash}
end,
SCT_sig = get_sct(Hash, TimestampedEntry),
{[{sct_version, ?PROTOCOL_VERSION},
{id, base64:encode(plop:get_logid())},
{timestamp, TimestampedEntry#timestamped_entry.timestamp},
{extensions, base64:encode(<<>>)},
{signature, base64:encode(SCT_sig)}]}.
-spec timestamped_entry(integer(), entry_type(), binary(), binary()) ->
timestamped_entry().
timestamped_entry(Timestamp, EntryType, LeafCert, CertChain) ->
SignedEntry =
case EntryType of
x509_entry ->
#signed_x509_entry{asn1_cert = LeafCert};
precert_entry ->
{DetoxedLeafTBSCert, IssuerKeyHash} =
x509:detox(LeafCert, CertChain),
#signed_precert_entry{
issuer_key_hash = IssuerKeyHash,
tbs_certificate = DetoxedLeafTBSCert}
end,
#timestamped_entry{timestamp = Timestamp,
entry_type = EntryType,
signed_entry = SignedEntry}.
-spec deserialise_mtl(binary()) -> mtl().
deserialise_mtl(Data) ->
<<LeafVersionBin:1/binary,
LeafTypeBin:1/binary,
TimestampedEntryBin/binary>> = Data,
#mtl{leaf_version = deserialise_leaf_version(LeafVersionBin),
leaf_type = deserialise_leaf_type(LeafTypeBin),
entry = deserialise_timestampedentry(TimestampedEntryBin)}.
-spec deserialise_timestampedentry(binary()) -> timestamped_entry().
deserialise_timestampedentry(Data) ->
<<Timestamp:64, EntryTypeBin:2/binary, RestData/binary>> = Data,
EntryType = deserialise_entry_type(EntryTypeBin),
{SignedEntry, ExtensionsBin} =
case EntryType of
x509_entry ->
deserialise_signed_x509_entry(RestData);
precert_entry ->
deserialise_signed_precert_entry(RestData)
end,
{Extensions, <<>>} = decode_tls_vector(ExtensionsBin, 2),
#timestamped_entry{timestamp = Timestamp,
entry_type = EntryType,
signed_entry = SignedEntry,
extensions = Extensions}.
-spec deserialise_signed_x509_entry(binary()) -> {signed_x509_entry(), binary()}.
deserialise_signed_x509_entry(Data) ->
{E, D} = decode_tls_vector(Data, 3),
{#signed_x509_entry{asn1_cert = E}, D}.
-spec deserialise_signed_precert_entry(binary()) ->
{signed_precert_entry(), binary()}.
deserialise_signed_precert_entry(Data) ->
<<IssuerKeyHash:32/binary, RestData/binary>> = Data,
{TBSCertificate, RestData2} = decode_tls_vector(RestData, 3),
{#signed_precert_entry{issuer_key_hash = IssuerKeyHash,
tbs_certificate = TBSCertificate},
RestData2}.
-spec entries(non_neg_integer(), non_neg_integer()) -> {[{entries, list()},...]}.
entries(Start, End) ->
{[{entries, x_entries(plop:get(Start, End))}]}.
-spec entry_and_proof(non_neg_integer(), non_neg_integer()) -> {[{_,_},...]}.
entry_and_proof(Index, TreeSize) ->
case plop:inclusion_and_entry(Index, TreeSize) of
{ok, Entry, Path} ->
{Type, MTLText, Cert, Chain} = unpack_entry(Entry),
ExtraData = extra_data(Type, Cert, Chain),
{[{leaf_input, base64:encode(MTLText)},
{extra_data, base64:encode(ExtraData)},
{audit_path, [base64:encode(X) || X <- Path]}]};
{notfound, Msg} ->
{[{success, false},
{error_message, list_to_binary(Msg)}]}
end.
-define(CACHE_TABLE, catlfish_cache).
init_cache_table() ->
case ets:info(?CACHE_TABLE) of
undefined -> ok;
_ -> ets:delete(?CACHE_TABLE)
end,
ets:new(?CACHE_TABLE, [set, public, named_table]).
verify_mtl(MTL, LeafCert, CertChain) ->
Timestamp = MTL#mtl.entry#timestamped_entry.timestamp,
EntryType = MTL#mtl.entry#timestamped_entry.entry_type,
TSE = timestamped_entry(Timestamp, EntryType, LeafCert, CertChain),
case MTL of
#mtl{leaf_version = v1,
leaf_type = timestamped_entry,
entry = TSE} ->
ok;
_ ->
error
end.
verify_entry(Entry) ->
RootCerts = known_roots(),
verify_entry(Entry, RootCerts).
%% Used from plop.
verify_entry(PackedEntry, RootCerts) ->
{_Type, MTLText, Cert, Chain} = unpack_entry(PackedEntry),
case x509:normalise_chain(RootCerts, [Cert | Chain]) of
{ok, [Cert | FullChain]} ->
case verify_mtl(deserialise_mtl(MTLText), Cert, FullChain) of
ok ->
{ok, ht:leaf_hash(MTLText)};
error ->
{error, "MTL verification failed"}
end;
{error, Reason} ->
{error, Reason}
end.
%% Used from plop.
entryhash_from_entry(PackedEntry) ->
{_Type, _MTLText, Cert, Chain} = unpack_entry(PackedEntry),
crypto:hash(sha256, [Cert | Chain]).
%% Private functions.
-spec pack_entry(normal|precert, binary(), binary(), [binary()]) -> binary().
pack_entry(Type, MTLText, EndEntityCert, CertChain) ->
[{<<"MTL1">>, MTLText},
{case Type of
normal -> <<"EEC1">>;
precert -> <<"PRC1">>
end, EndEntityCert},
{<<"CHN1">>,
list_to_binary(
[tlv:encode(<<"X509">>, E) || E <- CertChain])}].
-spec unpack_entry(binary()) -> {normal|precert, binary(), binary(), [binary()]}.
unpack_entry(Entry) ->
[{<<"MTL1">>, MTLText}|Rest1] = Entry,
[{EECType, EndEntityCert}|Rest2] = Rest1,
Type = case EECType of
<<"EEC1">> ->
normal;
<<"PRC1">> ->
precert
end,
[{<<"CHN1">>, PackedChain}|_Rest3] = Rest2,
Chain = unpack_certchain(PackedChain),
{Type, MTLText, EndEntityCert, Chain}.
unpack_certchain(<<>>) ->
[];
unpack_certchain(Data) ->
{<<"X509">>, Unpacked, Rest} = tlv:decode(Data),
[Unpacked | unpack_certchain(Rest)].
extra_data(Type, Cert, Chain) ->
EncodedChain = encode_tls_vector(
list_to_binary(
[encode_tls_vector(C, 3) || C <- Chain]), 3),
case Type of
normal ->
EncodedChain;
precert ->
list_to_binary(
[encode_tls_vector(Cert, 3) | EncodedChain])
end.
-spec x_entries([{non_neg_integer(), binary(), binary()}]) -> list().
x_entries([]) ->
[];
x_entries([H|T]) ->
{_Index, _Hash, Entry} = H,
{Type, MTL, Cert, Chain} = unpack_entry(Entry),
ExtraData = extra_data(Type, Cert, Chain),
[{[{leaf_input, base64:encode(MTL)},
{extra_data, base64:encode(ExtraData)}]} | x_entries(T)].
-spec encode_tls_vector(binary(), non_neg_integer()) -> binary().
encode_tls_vector(Binary, LengthLen) ->
Length = byte_size(Binary),
<<Length:LengthLen/integer-unit:8, Binary/binary>>.
-spec decode_tls_vector(binary(), non_neg_integer()) -> {binary(), binary()}.
decode_tls_vector(Binary, LengthLen) ->
<<Length:LengthLen/integer-unit:8, Rest/binary>> = Binary,
<<ExtractedBinary:Length/binary-unit:8, Rest2/binary>> = Rest,
{ExtractedBinary, Rest2}.
-define(ROOTS_CACHE_KEY, roots).
update_known_roots() ->
case application:get_env(catlfish, known_roots_path) of
{ok, Dir} -> update_known_roots(Dir);
undefined -> []
end.
update_known_roots(Directory) ->
known_roots(Directory, update_tab).
known_roots() ->
case application:get_env(catlfish, known_roots_path) of
{ok, Dir} -> known_roots(Dir, use_cache);
undefined -> []
end.
-spec known_roots(file:filename(), use_cache|update_tab) -> [binary()].
known_roots(Directory, CacheUsage) ->
case CacheUsage of
use_cache ->
case ets:lookup(?CACHE_TABLE, ?ROOTS_CACHE_KEY) of
[] ->
read_files_and_update_table(Directory);
[{roots, DerList}] ->
DerList
end;
update_tab ->
read_files_and_update_table(Directory)
end.
read_files_and_update_table(Directory) ->
Certs = x509:read_pemfiles_from_dir(Directory),
Proper = x509:self_signed(Certs),
case length(Certs) - length(Proper) of
0 -> ok;
N -> lager:warning(
"Ignoring ~p root certificates not signing themselves properly",
[N])
end,
true = ets:insert(?CACHE_TABLE, {?ROOTS_CACHE_KEY, Proper}),
lager:info("Known roots imported: ~p", [length(Proper)]),
Proper.
%%%%%%%%%%%%%%%%%%%%
%% Testing internal functions.
-define(PEMFILES_DIR_OK, "test/testdata/known_roots").
-define(PEMFILES_DIR_NONEXISTENT, "test/testdata/nonexistent-dir").
read_pemfiles_test_() ->
{setup,
fun() ->
init_cache_table(),
{known_roots(?PEMFILES_DIR_OK, update_tab),
known_roots(?PEMFILES_DIR_OK, use_cache)}
end,
fun(_) -> ets:delete(?CACHE_TABLE, ?ROOTS_CACHE_KEY) end,
fun({L, LCached}) ->
[?_assertMatch(4, length(L)),
?_assertEqual(L, LCached)]
end}.
read_pemfiles_fail_test_() ->
{setup,
fun() ->
init_cache_table(),
known_roots(?PEMFILES_DIR_NONEXISTENT, update_tab)
end,
fun(_) -> ets:delete(?CACHE_TABLE, ?ROOTS_CACHE_KEY) end,
fun(Empty) -> [?_assertMatch([], Empty)] end}.
|