Add toy length extension victim server

lenex/.gitignore

@@ -0,0 +1,18 @@
+.rebar3
+_*
+.eunit
+*.o
+*.beam
+*.plt
+*.swp
+*.swo
+.erlang.cookie
+ebin
+log
+erl_crash.dump
+.rebar
+logs
+_build
+.idea
+*.iml
+rebar3.crashdump

lenex/LICENSE

@@ -0,0 +1,191 @@
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+   9. Accepting Warranty or Additional Liability. While redistributing
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+   Copyright 2018, Andrey Mayorov <a.mayorov@rbkmoney.com>.
+
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+

lenex/README.md

@@ -0,0 +1,12 @@
+# lenex
+
+Length Extension Attack victim server.
+
+## Build
+
+    $ rebar3 release
+
+## Run
+
+    $ cd _build/default/rel/lenex
+    $ ./bin/lenex

lenex/config/sys.config

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+[
+
+    {lenex, [
+        {keyfile, "var/key"}
+    ]}
+
+].

lenex/config/vm.args

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+-sname lenex
+
+-setcookie lenex
+
++K true
++A 10

lenex/rebar.config

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+{erl_opts, [debug_info]}.
+{deps, [
+    {cowboy, "2.4.0"},
+    {genlib, {git, "https://github.com/rbkmoney/genlib", master}}
+]}.
+
+{relx, [
+    {release, {'lenex', "0.1.0"}, [
+        lenex
+    ]},
+    {sys_config            , "./config/sys.config"},
+    {vm_args               , "./config/vm.args"},
+    {dev_mode              , true},
+    {include_erts          , false},
+    {extended_start_script , false},
+    %% wapi
+    {overlay, [
+        {mkdir , "var"},
+        {copy  , "var/key", "var/key"}
+    ]}
+
+]}.

lenex/rebar.lock

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+{"1.1.0",
+[{<<"cowboy">>,{pkg,<<"cowboy">>,<<"2.4.0">>},0},
+ {<<"cowlib">>,{pkg,<<"cowlib">>,<<"2.3.0">>},1},
+ {<<"genlib">>,
+  {git,"https://github.com/rbkmoney/genlib",
+       {ref,"8501050c19e5a36063cf0ae0d181245662bdfa32"}},
+  0},
+ {<<"ranch">>,{pkg,<<"ranch">>,<<"1.5.0">>},1}]}.
+[
+{pkg_hash,[
+ {<<"cowboy">>, <<"F1B72FABE9C8A5FC64AC5AC85FB65474D64733D1DF52A26FAD5D4BA3D9F70A9F">>},
+ {<<"cowlib">>, <<"BBD58EF537904E4F7C1DD62E6AA8BC831C8183CE4EFA9BD1150164FE15BE4CAA">>},
+ {<<"ranch">>, <<"F04166F456790FEE2AC1AA05A02745CC75783C2BFB26D39FAF6AEFC9A3D3A58A">>}]}
+].

lenex/src/lenex.app.src

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+{application, lenex, [
+    {description, "Length Extension Victim"},
+    {vsn, "0.1.0"},
+    {registered, []},
+    {mod, {lenex_app, []}},
+    {applications, [
+        kernel,
+        stdlib,
+        cowboy,
+        genlib
+    ]},
+    {env,[]},
+    {modules, []},
+    {maintainers, []},
+    {licenses, ["Apache 2.0"]},
+    {links, []}
+]}.

lenex/src/lenex_app.erl

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+-module(lenex_app).
+
+-behaviour(application).
+
+%% Application callbacks
+-export([start/2, stop/1]).
+
+%% API
+
+-spec start(_StartType, _StartArgs) ->
+    {ok, pid()}.
+
+start(_StartType, _StartArgs) ->
+    lenex_sup:start_link().
+
+-spec stop(_) ->
+    ok.
+
+stop(_State) ->
+    ok.

lenex/src/lenex_crypto.erl

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+-module(lenex_crypto).
+
+-export([sign/2]).
+-export([verify/3]).
+
+%%
+
+-type message()   :: binary().
+-type key()       :: <<_:128>>.
+-type signature() :: <<_:256>>.
+
+-spec sign(message(), key()) ->
+    signature().
+
+-spec verify(message(), signature(), key()) ->
+    boolean().
+
+sign(M, K) ->
+    crypto:hash(sha256, <<K/binary, M/binary>>).
+
+verify(M, T, K) ->
+    sign(M, K) =:= T.

lenex/src/lenex_handler.erl

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+-module(lenex_handler).
+
+-export([init/2]).
+
+%%
+
+-spec init(cowboy_req:req(), Opts) ->
+    {ok, cowboy_req:req(), Opts}.
+
+init(Req0, Opts) ->
+    Req1 = init(cowboy_req:method(Req0), Req0, Opts),
+    {ok, Req1, Opts}.
+
+init(<<"GET">>, Req, Opts) ->
+    QsVals = maps:from_list(cowboy_req:parse_qs(Req)),
+    case maps:find(<<"user">>, QsVals) of
+        {ok, Username} ->
+            handle_get_status(Username, Req, Opts);
+        error ->
+            cowboy_req:reply(400, Req)
+    end;
+
+init(<<"POST">>, Req0, Opts) ->
+    case cowboy_req:read_body(Req0, #{length => 64000, period => 30000}) of
+        {ok, Body, Req1} ->
+            handle_post_status(maps:from_list(cow_qs:parse_qs(Body)), Body, Req1, Opts);
+        _ ->
+            cowboy_req:reply(413, Req0)
+    end;
+
+init(_, Req, _Opts) ->
+    cowboy_req:reply(405, Req).
+
+%%
+
+handle_get_status(Username, Req, #{db := DB}) ->
+    case read_db({Username, status}, DB) of
+        {ok, Status} ->
+            cowboy_req:reply(
+                200,
+                #{<<"content-type">> => <<"text/plain">>},
+                Status,
+                Req
+            );
+        {error, notfound} ->
+            cowboy_req:reply(204, Req)
+    end.
+
+%%
+
+handle_post_status(QsVals, Body, Req0, Opts) ->
+    Username = maps:get(<<"user">>, QsVals, undefined),
+    Status = maps:get(<<"v">>, QsVals, undefined),
+    Digest = cowboy_req:header(<<"signature">>, Req0),
+    Sign = try genlib_format:hex_to_binary(Digest) catch
+        error:badarg ->
+            undefined
+    end,
+    case lists:all(fun (V) -> V /= undefined end, [Username, Status, Sign]) of
+        true ->
+            case verify_signature(Body, Sign, Opts) of
+                true ->
+                    post_status(Username, Status, Req0, Opts);
+                false ->
+                    cowboy_req:reply(403, Req0)
+            end;
+        false ->
+            cowboy_req:reply(400, Req0)
+    end.
+
+verify_signature(Body, Sign, #{key := Key}) ->
+    lenex_crypto:verify(Body, Sign, Key).
+
+post_status(Username, Status, Req0, #{db := DB}) ->
+    ok = write_db({Username, status}, Status, DB),
+    cowboy_req:reply(200, Req0).
+
+%%
+
+read_db(Key, DB) ->
+    case ets:lookup(DB, Key) of
+        [{Key, Value}] ->
+            {ok, Value};
+        [] ->
+            {error, notfound}
+    end.
+
+write_db(Key, Value, DB) ->
+    true = ets:insert(DB, [{Key, Value}]),
+    ok.

lenex/src/lenex_sup.erl

@@ -0,0 +1,58 @@
+-module(lenex_sup).
+
+-behaviour(supervisor).
+
+%% API
+-export([start_link/0]).
+
+%% Supervisor callbacks
+-export([init/1]).
+
+-define(SERVER, ?MODULE).
+
+%% API functions
+
+-spec start_link() ->
+    {ok, pid()}.
+
+start_link() ->
+    supervisor:start_link(?MODULE, []).
+
+%% Supervisor callbacks
+
+-spec init([]) ->
+    {ok, {supervisor:sup_flags(), [supervisor:child_spec()]}}.
+
+init([]) ->
+    Flags = #{strategy => one_for_all},
+    {ok, {Flags, [get_cowboy_child_spec({0, 0, 0, 0}, 8001)]}}.
+
+get_cowboy_child_spec(IP, Port) ->
+    Key = read_key(),
+    DB = ets:new(?MODULE, [public, set]),
+    Dispatch = cowboy_router:compile([
+        {'_', [
+            {"/status", lenex_handler, #{
+                key => Key,
+                db => DB
+            }}
+        ]}
+    ]),
+    ranch:child_spec(
+        ?SERVER,
+        ranch_tcp,
+        [
+            {ip, IP},
+            {port, Port},
+            {num_acceptors, 4}
+        ],
+        cowboy_clear,
+        #{
+            env => #{dispatch => Dispatch}
+        }
+    ).
+
+read_key() ->
+    {ok, Path} = application:get_env(lenex, keyfile),
+    {ok, Key} = file:read_file(Path),
+    Key.

lenex/var/key

@@ -0,0 +1 @@
+<EFBFBD>-<2D>РУЛj<D09B>gхcм&в