Super weird http issue

Questions & Help Questions
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5

Decrypting TLS would be possible in two scenarios:

  1. You have access to the server’s private key and you constrain the negotiated cipher suites to ensure the key exchange does not use (EC)DHE, or
  2. You write the master secret for the session you want to decode to a file

This last option can work both on the server side (if you control the server) or on the client side (using Erlang’s :ssl.connection_information(socket, [:client_random, :master_secret]).

But there is an easier way: use Erlang’s tracing functionality, e.g. using :dbg or some higher level abstraction such as recon:

iex(1)> :dbg.tracer()                                                            
{:ok, #PID<0.258.0>}
iex(2)> :dbg.p(:all, :call)                                                      
{:ok, [{:matched, :nonode@nohost, 119}]}
iex(3)> :dbg.tp({Mint.Core.Transport.SSL, :send, :_}, :cx)                       
{:ok, [{:matched, :nonode@nohost, 1}, {:saved, :cx}]}
iex(4)> {:ok, response} = Mojito.request(method: :get, url: "https://github.com")
(<0.269.0>) call 'Elixir.Mint.Core.Transport.SSL':send({sslsocket,{gen_tcp,#Port<0.6>,tls_connection,undefined},
           [<0.303.0>,<0.302.0>]},[[<<"GET">>,32,<<"/">>,<<" HTTP/1.1\r\n">>],
 [[[<<>>,<<"content-length">>,<<": ">>,<<"0">>,<<"\r\n">>],
   <<"host">>,<<": ">>,<<"github.com">>,<<"\r\n">>],
  <<"user-agent">>,<<": ">>,<<"mint/1.0.0">>,<<"\r\n">>],
 <<"\r\n">>,<<>>]) ({'Elixir.Mint.HTTP1',request,5})
(<0.269.0>) returned from 'Elixir.Mint.Core.Transport.SSL':send/2 -> ok
{:ok,
 %Mojito.Response{...}

It takes a second to spot the actual request data in the output and perhaps reformat it, but it is much easier than setting up TLS decoding :slight_smile: