[erlang-bugs] Type errors in ssl application since OTP 17.0-rc2

[Johannes Weißl]

Hello,

we noticed dialyzer warnings in our application with OTP 17.0-rc2.
Through "git bisect" I could determine the commit which made the error
apparent:

48c3778 Ingela Anderton Andin   Fri Feb 14 17:08:14 2014 +0100
ssl: Fix possible mismatch between SSL/TLS version and default ciphers

I attached a small example (ssl_bug.erl), it can be compiled and run
like this:

erlc ssl_bug.erl
erl -noshell -s ssl_bug listen no_use_ssl -s init stop
erl -noshell -s ssl_bug listen use_ssl -s init stop

Although the program seems correct, dialyzer throws a warning:

dialyzer --build_plt --apps erts kernel stdlib mnesia compiler asn1 \
    syntax_tools hipe crypto public_key ssl
dialyzer ssl_bug.erl
ssl_bug.erl:30: The call ssl:sockname(Socket::port()) will never return since the success typing is ({'sslsocket',_,pid() | {port(),{'config',_,_,_,_,{_,_,_,_},_}}}) -> any() and the contract is (#sslsocket{}) -> {'ok',{inet:ip_address(),inet:port_number()}} | {'error',reason()}

There are multiple type issues in the ssl application, which could be
responsible for this, e.g.:
dtls_handshake.erl:57: The call dtls_record:highest_protocol_version(Versions::'undefined' | ['dtlsv1' | 'dtlsv1.2' | 'sslv3' | 'tlsv1' | 'tlsv1.1' | 'tlsv1.2']) will never return since the success typing is ([any(),...]) -> any() and the contract is ([tls_version()]) -> tls_version()
(tls_version() is {integer(), integer()})

Regards,
Johannes Weißl
-------------- next part --------------
-module(ssl_bug).

-export([listen/1]).

listen(Args) ->
    UseSsl = proplists:get_bool(use_ssl, Args),
    io:format("Use SSL: ~p~n", [UseSsl]),
    case gen_tcp_or_ssl_listen(0, [], UseSsl) of
        {ok,ListenSocket} ->
            {ok,{Address,Port}} = inet_or_ssl_sockname(ListenSocket, UseSsl),
            io:format("Listening on ~p port ~p~n", [Address, Port]),
            {ok,ListenSocket};
        {error,Reason} ->
            io:format("Error, reason: ~p~n", [Reason]),
            {error,Reason}
    end.

gen_tcp_or_ssl_listen(Port, Options, false) ->
    gen_tcp:listen(Port, Options);
gen_tcp_or_ssl_listen(Port, Options, true) ->
    DefaultOptions = [{ciphers,ssl:cipher_suites()}],
    case ssl:start() of
        ok -> ssl:listen(Port, Options ++ DefaultOptions);
        Error={error,_} -> Error
    end.

inet_or_ssl_sockname(Socket, false) ->
    inet:sockname(Socket);
inet_or_ssl_sockname(Socket, true) ->
    ssl:sockname(Socket).