Add unsafe_encode/2 to forego size check

I noticed that the 'hash' serialization type wasn't in the `known_type()` set, although it was supported otherwise.
This PR adds it to the `known_type()` and also exports the type `gmser_api_encoder:known_type()`.

Also, some more tests are added to try to detect this sort of thing in the future.

Co-authored-by: Ulf Wiger <ulf@wiger.net>
Reviewed-on: #56

src/gmser_api_encoder.erl

@@ -13,7 +13,13 @@
          safe_decode/2,
          byte_size_for_type/1]).
 
--export_type([encoded/0]).
+-export([encode_keypair/1,
+         safe_decode_keypair/1]).
+
+-export([unsafe_encode/2]).   %% Encode without size checks
+
+-export_type([encoded/0,
+              known_type/0]).
 
 -type known_type() :: key_block_hash
                     | micro_block_hash
@@ -38,6 +44,7 @@
                     | native_token
                     | commitment
                     | peer_pubkey
+                    | hash
                     | state
                     | poi
                     | state_trees
@@ -51,14 +58,66 @@
 -type payload() :: binary().
 -type encoded() :: binary().
 
+-type keypair() :: #{public := <<_:(32*8)>>, secret := <<_:(64*8)>>}.
+-type encoded_keypair() :: #{binary() => binary()}.
+
+-export_type([ keypair/0
+             , encoded_keypair/0 ]).
+
 -define(BASE58, 1).
 -define(BASE64, 2).
 
+-spec encode_keypair(keypair()) -> encoded_keypair().
+encode_keypair(#{public := Pub, secret := Sec}) ->
+    case Sec of
+        <<Seed:32/binary, Pub1:32/binary>> when Pub1 =:= Pub ->
+            #{ <<"pub">> => encode(account_pubkey, Pub)
+             , <<"priv">> => encode(account_seckey, Seed) };
+        _ ->
+            erlang:error(invalid_keypair)
+    end.
+
+-spec safe_decode_keypair(encoded_keypair()) -> {'ok', keypair()} | {'error', atom()}.
+safe_decode_keypair(#{<<"pub">> := EncPub, <<"priv">> := EncPriv}) ->
+    case safe_decode(account_pubkey, EncPub) of
+        {ok, Pub} ->
+            case safe_decode(account_seckey, EncPriv) of
+                {ok, Seed} when byte_size(Seed) =:= 32 ->
+                    case enacl:sign_seed_keypair(Seed) of
+                        #{public := Pub, secret := _} = KP ->
+                            {ok, KP};
+                        _ ->
+                            {error, illegal_encoding}
+                    end;
+                {ok, <<Seed:32/binary, Pub:32/binary>>} ->
+                    case enacl:sign_seed_keypair(Seed) of
+                        #{public := Pub} = KP ->
+                            {ok, KP};
+                        _ ->
+                            {error, illegal_encoding}
+                    end;
+                {ok, _} ->
+                    {error, illegal_encoding};
+                {error, _} = Error1 ->
+                    Error1
+            end;
+        Error ->
+            Error
+    end.
+
 -spec encode(known_type(), payload() | gmser_id:id()) -> encoded().
 encode(id_hash, Payload) ->
     {IdType, Val} = gmser_id:specialize(Payload),
     encode(id2type(IdType), Val);
 encode(Type, Payload) ->
+    case type_size_check(Type, Payload) of
+        ok ->
+            unsafe_encode(Type, Payload);
+        {error, Reason} ->
+            erlang:error(Reason)
+    end.
+
+unsafe_encode(Type, Payload) ->
     Pfx = type2pfx(Type),
     Enc = case type2enc(Type) of
               ?BASE58 -> base58_check(Payload);
@@ -66,6 +125,7 @@ encode(Type, Payload) ->
           end,
     <<Pfx/binary, "_", Enc/binary>>.
 
+
 -spec decode(binary()) -> {known_type(), payload()}.
 decode(Bin0) ->
     case split(Bin0) of
@@ -81,6 +141,13 @@ decode(Bin0) ->
             erlang:error(missing_prefix)
     end.
 
+type_size_check(account_seckey, Bin) ->
+    case byte_size(Bin) of
+        Sz when Sz =:= 32; Sz =:= 64 ->
+            ok;
+        _ ->
+            {error, incorrect_size}
+    end;
 type_size_check(Type, Bin) ->
     case byte_size_for_type(Type) of
         not_applicable -> ok;

test/gmser_api_encoder_tests.erl

@@ -22,10 +22,39 @@
                , {native_token      , 32}
                , {commitment        , 32}
                , {peer_pubkey       , 32}
+               , {hash              , 32}
                , {state             , 32}
                , {poi               , not_applicable}]).
 
 encode_decode_test_() ->
+    encode_decode_test_(?TYPES).
+
+encode_decode_known_types_test_() ->
+    KnownTypes = known_types(),
+    SizedTypes = [{T, ?TEST_MODULE:byte_size_for_type(T)} || T <- KnownTypes],
+    encode_decode_test_(SizedTypes).
+
+prefixes_are_known_types_test() ->
+    MappedPfxs = mapped_prefixes(),
+    KnownTypes = known_types(),
+    lists:foreach(
+      fun({Pfx, Type}) ->
+              case lists:member(Type, KnownTypes) of
+                  true -> ok;
+                  false ->
+                      error({not_a_known_type, Pfx, Type})
+              end
+      end, MappedPfxs),
+    lists:foreach(
+      fun(Type) ->
+              case lists:keyfind(Type, 2, MappedPfxs) of
+                  {_, _} -> ok;
+                  false ->
+                      error({has_no_mapped_prefix, Type})
+              end
+      end, KnownTypes).
+
+encode_decode_test_(Types) ->
     [{"Byte sizes are correct",
       fun() ->
           lists:foreach(
@@ -33,7 +62,7 @@ encode_decode_test_() ->
                   {_Type, _, ByteSize} = {Type, ByteSize,
                                           ?TEST_MODULE:byte_size_for_type(Type)}
               end,
-              ?TYPES)
+              Types)
       end
      },
      {"Serialize/deserialize known types",
@@ -50,7 +79,7 @@ encode_decode_test_() ->
                     {Type, Key} = ?TEST_MODULE:decode(EncodedKey),
                     {ok, Key} = ?TEST_MODULE:safe_decode(Type, EncodedKey)
               end,
-              ?TYPES)
+              Types)
       end
      },
      {"Key size check works",
@@ -58,17 +87,18 @@ encode_decode_test_() ->
           lists:foreach(
               fun({_Type, not_applicable}) -> ok;
                  ({Type, ByteSize}) ->
-                    CheckIlligalSize =
+                    CheckIllegalSize =
                         fun(S) ->
                             Key = <<42:S/unit:8>>,
-                            EncodedKey = ?TEST_MODULE:encode(Type, Key),
+                            ?assertError(incorrect_size, ?TEST_MODULE:encode(Type, Key)),
+                            EncodedKey = ?TEST_MODULE:unsafe_encode(Type, Key),  %% no size check
                             {error, invalid_encoding} = ?TEST_MODULE:safe_decode(Type, EncodedKey)
                         end,
-                    CheckIlligalSize(0),
+                    CheckIllegalSize(0),
-                    CheckIlligalSize(ByteSize - 1),
+                    CheckIllegalSize(ByteSize - 1),
-                    CheckIlligalSize(ByteSize + 1)
+                    CheckIllegalSize(ByteSize + 1)
               end,
-              ?TYPES)
+              Types)
       end
      },
      {"Missing prefix",
@@ -91,7 +121,7 @@ encode_decode_test_() ->
                     <<_WholePrefix:3/unit:8, RestOfKey2/binary>> = EncodedKey,
                     {error, invalid_encoding} = ?TEST_MODULE:safe_decode(Type, RestOfKey2)
               end,
-              ?TYPES)
+              Types)
       end
      },
      {"Piece of encoded key",
@@ -110,7 +140,7 @@ encode_decode_test_() ->
                     {error, invalid_encoding} = ?TEST_MODULE:safe_decode(Type, HalfKey),
                     {error, invalid_encoding} = ?TEST_MODULE:safe_decode(Type, RestOfKey)
               end,
-              ?TYPES)
+              Types)
       end
      },
      {"Encode/decode binary with only zeros",
@@ -131,8 +161,58 @@ encode_decode_test_() ->
                       Encoded1 = base58:binary_to_base58(Bin),
                       Decoded1 = base58:base58_to_binary(Encoded1),
                       ?assertEqual(Bin, Decoded1)
-                  end, ?TYPES)
+                  end, Types)
             end,
             Bins)
-      end}
+      end},
+     {"Encode/decode keypairs",
+      fun() ->
+              KP1 = enacl:sign_keypair(),
+              Enc1 = ?TEST_MODULE:encode_keypair(KP1),
+              {ok, KP1} = ?TEST_MODULE:safe_decode_keypair(Enc1),
+              KP2 = enacl:sign_keypair(),
+              Enc2 = ?TEST_MODULE:encode_keypair(KP2),
+              {ok, KP2} = ?TEST_MODULE:safe_decode_keypair(Enc2),
+              BadEnc = Enc1#{~"priv" => maps:get(~"priv", Enc2)},
+              {error, illegal_encoding} = ?TEST_MODULE:safe_decode_keypair(BadEnc)
+      end
+     },
+     {"Encode AND decode both 32-byte and 64-byte account_seckey",
+      fun() ->
+              %% Originally, we could encode a 64-byte seckey, but decode would fail.
+              #{public := Pub, secret := Sec} = enacl:sign_keypair(),
+              <<Seed:32/binary, Pub:32/binary>> = Sec,
+              EncSeed = ?TEST_MODULE:encode(account_seckey, Seed),
+              EncSec = ?TEST_MODULE:encode(account_seckey, Sec),
+              {ok, Seed} = ?TEST_MODULE:safe_decode(account_seckey, EncSeed),
+              {ok, Sec} = ?TEST_MODULE:safe_decode(account_seckey, EncSec)
+      end
+     }
      ].
+
+known_types() ->
+    Forms = get_forms(),
+    [{type, _, union, Types}] =
+        [Def || {attribute, _, type, {known_type, Def, []}} <- Forms],
+    [Name || {atom,_, Name} <- Types].
+
+mapped_prefixes() ->
+    Forms = get_forms(),
+    [Clauses] = [Cs || {function,_,pfx2type,1,Cs} <- Forms],
+    Abst = [{B, A} || {clause,_,[B],[],[A]} <- Clauses],
+    lists:map(
+      fun({B, A}) ->
+              {eval_expr(B), eval_expr(A)}
+      end, Abst).
+
+get_forms() ->
+    get_forms(code:which(?TEST_MODULE)).
+
+get_forms(Beam) ->
+    {ok, {_, [{abstract_code, {raw_abstract_v1, Forms}}]}} =
+        beam_lib:chunks(Beam, [abstract_code]),
+    Forms.
+
+eval_expr(Expr) ->
+    {value, Val, []} = erl_eval:expr(Expr, []),
+    Val.