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gen_smtp_server_session.erl
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%%% Copyright 2009 Andrew Thompson <andrew@hijacked.us>. All rights reserved.
%%%
%%% Redistribution and use in source and binary forms, with or without
%%% modification, are permitted provided that the following conditions are met:
%%%
%%% 1. Redistributions of source code must retain the above copyright notice,
%%% this list of conditions and the following disclaimer.
%%% 2. Redistributions in binary form must reproduce the above copyright
%%% notice, this list of conditions and the following disclaimer in the
%%% documentation and/or other materials provided with the distribution.
%%%
%%% THIS SOFTWARE IS PROVIDED BY THE FREEBSD PROJECT ``AS IS'' AND ANY EXPRESS OR
%%% IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
%%% MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
%%% EVENT SHALL THE FREEBSD PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
%%% INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
%%% (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
%%% LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
%%% ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
%%% (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
%%% SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
%% @doc Process representing a SMTP session, extensible via a callback module. This
%% module is implemented as a behaviour that the callback module should
%% implement. To see the details of the required callback functions to provide,
%% please see `smtp_server_example'.
%% @see smtp_server_example
-module(gen_smtp_server_session).
-behaviour(gen_server).
-behaviour(ranch_protocol).
-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").
-endif.
-define(DEFAULT_MAXSIZE, 10485760). %10mb
-define(BUILTIN_EXTENSIONS, [{"SIZE", integer_to_list(?DEFAULT_MAXSIZE)}, {"8BITMIME", true}, {"PIPELINING", true}, {"SMTPUTF8", true}]).
-define(TIMEOUT, 180000). % 3 minutes
%% External API
-export([start_link/3, start_link/4]).
-export([ranch_init/1]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2,
code_change/3]).
-export_type([options/0, error_class/0, protocol_message/0]).
-include_lib("hut/include/hut.hrl").
-record(envelope,
{
from :: binary() | 'undefined',
to = [] :: [binary()],
data = <<>> :: binary(),
expectedsize = 0 :: pos_integer() | 0,
auth = {<<>>, <<>>} :: {binary(), binary()}, % {"username", "password"}
flags = [] :: [smtputf8 | '8bitmime' | '7bit']
}
).
-record(state,
{
socket = erlang:error({undefined, socket}) :: port() | tuple(),
module = erlang:error({undefined, module}) :: atom(),
transport :: module(),
ranch_ref :: ranch:ref(),
envelope = undefined :: 'undefined' | #envelope{},
extensions = [] :: [{string(), string()}],
maxsize = ?DEFAULT_MAXSIZE :: pos_integer() | 'infinity',
waitingauth = false :: 'false' | 'plain' | 'login' | 'cram-md5',
authdata :: 'undefined' | binary(),
readmessage = false :: boolean(),
tls = false :: boolean(),
callbackstate :: any(),
protocol = smtp :: 'smtp' | 'lmtp',
options = [] :: [tuple()]
}
).
%% OTP-19: ssl:ssl_option()
%% OTP-20: ssl:ssl_option()
%% OTP-21: ssl:tls_server_option()
%% OTP-22: ssl:tls_server_option()
%% OTP-23: ssl:tls_server_option()
-ifdef(OTP_RELEASE).
-type tls_opt() :: ssl:tls_server_option().
-else.
-type tls_opt() :: ssl:ssl_option().
-endif.
-type options() :: [ {callbackoptions, any()}
| {certfile, file:name_all()} % deprecated, see tls_options
| {keyfile, file:name_all()} % deprecated, see tls_options
| {allow_bare_newlines, false | ignore | fix | strip}
| {hostname, inet:hostname()}
| {protocol, smtp | lmtp}
| {tls_options, [tls_opt()]}].
-type(state() :: any()).
-type(error_message() :: {error, string(), state()}).
-type error_class() :: tcp_closed | tcp_error
| ssl_closed | ssl_error
| data_rejected
| timeout
| out_of_order
| ssl_handshake_error
| send_error
| setopts_error
| data_receive_error.
-type protocol_message() :: string() | iodata().
-callback init(Hostname :: inet:hostname(), _SessionCount,
Peername :: inet:ip_address(), Opts :: any()) ->
{ok, Banner :: iodata(), CallbackState :: state()} | {stop, Reason :: any(), Message :: iodata()} | ignore.
-callback code_change(OldVsn :: any(), State :: state(), Extra :: any()) -> {ok, state()}.
-callback handle_HELO(Hostname :: binary(), State :: state()) ->
{ok, pos_integer() | 'infinity', state()} | {ok, state()} | error_message().
-callback handle_EHLO(Hostname :: binary(), Extensions :: list(), State :: state()) ->
{ok, list(), state()} | error_message().
-callback handle_STARTTLS(state()) -> state().
-callback handle_AUTH(AuthType :: login | plain | 'cram-md5', Username :: binary(),
Credential :: binary() | {binary(), binary()}, State :: state()) ->
{ok, state()} | any().
-callback handle_MAIL(From :: binary(), State :: state()) ->
{ok, state()} | {error, string(), state()}.
-callback handle_MAIL_extension(Extension :: binary(), State :: state()) ->
{ok, state()} | error.
-callback handle_RCPT(To :: binary(), State :: state()) ->
{ok, state()} | {error, string(), state()}.
-callback handle_RCPT_extension(Extension :: binary(), State :: state()) ->
{ok, state()} | error.
-callback handle_DATA(From :: binary(), To :: [binary(),...], Data :: binary(), State :: state()) ->
{ok | error, protocol_message(), state()} | {multiple, [{ok | error, protocol_message()}], state()}.
% the 'multiple' reply is only available for LMTP
-callback handle_RSET(State :: state()) -> state().
-callback handle_VRFY(Address :: binary(), State :: state()) ->
{ok, string(), state()} | {error, string(), state()}.
-callback handle_other(Verb :: binary(), Args :: binary(), state()) ->
{string() | noreply, state()}.
-callback handle_info(Info :: term(), State :: state()) ->
{noreply, NewState :: state()} |
{noreply, NewState :: state(), timeout() | hibernate} |
{stop, Reason :: term(), NewState :: term()}.
-callback handle_error(error_class(), any(), state()) -> {ok, state()} | {stop, Reason :: any(), state()}.
-callback terminate(Reason :: any(), state()) -> {ok, Reason :: any(), state()}.
-optional_callbacks([handle_info/2, handle_AUTH/4, handle_error/3]).
%% @doc Start a SMTP session linked to the calling process.
%% @see start/3
-spec start_link(Ref :: ranch:ref(), Transport :: module(),
{Callback :: module(), Options :: options()}) ->
{'ok', pid()}.
start_link(Ref, Transport, Options) ->
{ok, proc_lib:spawn_link(?MODULE, ranch_init, [{Ref, Transport, Options}])}.
start_link(Ref, _Sock, Transport, Options) ->
start_link(Ref, Transport, Options).
ranch_init({Ref, Transport, {Callback, Opts}}) ->
{ok, Socket} = ranch:handshake(Ref),
case init([Ref, Transport, Socket, Callback, Opts]) of
{ok, State, Timeout} ->
gen_server:enter_loop(?MODULE, [], State, Timeout);
{stop, Reason} ->
exit(Reason);
ignore ->
ok
end.
%% @private
-spec init(Args :: list()) -> {'ok', #state{}, ?TIMEOUT} | {'stop', any()} | 'ignore'.
init([Ref, Transport, Socket, Module, Options]) ->
Protocol = proplists:get_value(protocol, Options, smtp),
PeerName = case Transport:peername(Socket) of
{ok, {IPaddr, _Port}} -> IPaddr;
{error, _} -> error
end,
case PeerName =/= error
andalso Module:init(hostname(Options),
proplists:get_value(sessioncount, Options, 0), %FIXME
PeerName,
proplists:get_value(callbackoptions, Options, []))
of
false ->
Transport:close(Socket),
ignore;
{ok, Banner, CallbackState} ->
Transport:send(Socket, ["220 ", Banner, "\r\n"]),
ok = Transport:setopts(Socket, [{active, once},
{packet, line},
binary]),
{ok, #state{socket = Socket,
transport = Transport,
module = Module,
ranch_ref = Ref,
protocol = Protocol,
options = Options,
callbackstate = CallbackState}, ?TIMEOUT};
{stop, Reason, Message} ->
Transport:send(Socket, [Message, "\r\n"]),
Transport:close(Socket),
{stop, Reason};
ignore ->
Transport:close(Socket),
ignore
end.
%% @hidden
handle_call(stop, _From, State) ->
{stop, normal, ok, State};
handle_call(Request, _From, State) ->
{reply, {unknown_call, Request}, State}.
%% @hidden
handle_cast(_Msg, State) ->
{noreply, State}.
%% @hidden
-spec handle_info(Message :: any(), State :: #state{}) -> {'noreply', #state{}} | {'stop', any(), #state{}}.
handle_info({receive_data, {error, size_exceeded}}, #state{readmessage = true} = State) ->
send(State, "552 Message too large\r\n"),
setopts(State, [{active, once}]),
State1 = handle_error(data_rejected, size_exceeded, State),
{noreply, State1#state{readmessage = false, envelope = #envelope{}}, ?TIMEOUT};
handle_info({receive_data, {error, bare_newline}}, #state{readmessage = true} = State) ->
send(State, "451 Bare newline detected\r\n"),
setopts(State, [{active, once}]),
State1 = handle_error(data_rejected, bare_neline, State),
{noreply, State1#state{readmessage = false, envelope = #envelope{}}, ?TIMEOUT};
handle_info({receive_data, {error, Other}}, #state{readmessage = true} = State) ->
State1 = handle_error(data_receive_error, Other, State),
{stop, {error_receiving_data, Other}, State1};
handle_info({receive_data, Body, Rest},
#state{socket = Socket, transport = Transport, readmessage = true, envelope = Env, module=Module,
callbackstate = OldCallbackState, maxsize=MaxSize} = State) ->
% send the remainder of the data...
case Rest of
<<>> -> ok; % no remaining data
_ -> self() ! {Transport:name(), Socket, Rest}
end,
setopts(State, [{packet, line}]),
%% Unescape periods at start of line (rfc5321 4.5.2)
Data = re:replace(Body, <<"^\\\.">>, <<>>, [global, multiline, {return, binary}]),
#envelope{from = From, to = To} = Env,
case MaxSize =:= infinity orelse byte_size(Data) =< MaxSize of
true ->
{ResponseType, Value, CallbackState} = Module:handle_DATA(From, To, Data, OldCallbackState),
report_recipient(ResponseType, Value, State),
setopts(State, [{active, once}]),
{noreply, State#state{readmessage = false,
envelope = #envelope{},
callbackstate = CallbackState}, ?TIMEOUT};
false ->
send(State, "552 Message too large\r\n"),
setopts(State, [{active, once}]),
% might not even be able to get here anymore...
{noreply, State#state{readmessage = false, envelope = #envelope{}}, ?TIMEOUT}
end;
handle_info({SocketType, Socket, Packet}, #state{socket = Socket, transport = Transport, waitingauth = false} = State)
when SocketType =:= tcp; SocketType =:= ssl ->
case handle_request(parse_request(Packet), State) of
{ok, #state{options = Options, readmessage = true, maxsize = MaxSize} = NewState} ->
Session = self(),
Size = 0,
setopts(NewState, [{packet, raw}]),
%% TODO: change to receive asynchronously in the same process
spawn_opt(fun() ->
receive_data([], Transport, Socket, 0, Size, MaxSize, Session, Options)
end,
[link, {fullsweep_after, 0}]),
{noreply, NewState, ?TIMEOUT};
{ok, NewState} ->
setopts(NewState, [{active, once}]),
{noreply, NewState, ?TIMEOUT};
{stop, Reason, NewState} ->
{stop, Reason, NewState}
end;
handle_info({SocketType, Socket, Packet}, #state{socket = Socket} = State)
when SocketType =:= tcp; SocketType =:= ssl ->
%% We are in SASL state RFC-4954
Request = binstr:strip(binstr:strip(binstr:strip(binstr:strip(Packet, right, $\n), right, $\r), right, $\s), left, $\s),
?log(debug, "Got SASL request ~p", [Request]),
{ok, NewState} = handle_sasl(base64:decode(Request), State),
setopts(NewState, [{active, once}]),
{noreply, NewState, ?TIMEOUT};
handle_info({Kind, _Socket}, State) when Kind == tcp_closed;
Kind == ssl_closed ->
State1 = handle_error(Kind, [], State),
{stop, normal, State1};
handle_info({Kind, _Socket, Reason}, State) when Kind == ssl_error;
Kind == tcp_error ->
State1 = handle_error(Kind, Reason, State),
{stop, normal, State1};
handle_info(timeout, #state{socket = Socket, transport = Transport} = State) ->
send(State, "421 Error: timeout exceeded\r\n"),
Transport:close(Socket),
State1 = handle_error(timeout, [], State),
{stop, normal, State1};
handle_info(Info, #state{module=Module, callbackstate = OldCallbackState} = State) ->
case erlang:function_exported(Module, handle_info, 2) of
true ->
case Module:handle_info(Info, OldCallbackState) of
{noreply, NewCallbackState} ->
{noreply, State#state{callbackstate = NewCallbackState}};
{noreply, NewCallbackState, Action} ->
{noreply, State#state{callbackstate = NewCallbackState}, Action};
{stop, Reason, NewCallbackState} ->
{stop, Reason, State#state{callbackstate = NewCallbackState}}
end;
false ->
?log(debug, "Ignored message ~p", [Info]),
{noreply, State, ?TIMEOUT}
end.
%% @hidden
-spec terminate(Reason :: any(), State :: #state{}) -> 'ok'.
terminate(Reason, #state{socket = Socket, transport = Transport, module = Module,
callbackstate = CallbackState}) ->
ok = Transport:close(Socket),
Module:terminate(Reason, CallbackState).
%% @hidden
-spec code_change(OldVsn :: any(), State :: #state{}, Extra :: any()) -> {'ok', #state{}}.
code_change(OldVsn, #state{module = Module, callbackstate = CallbackState} = State, Extra) ->
% TODO - this should probably be the callback module's version or its checksum
CallbackState =
case catch Module:code_change(OldVsn, CallbackState, Extra) of
{ok, NewCallbackState} -> NewCallbackState;
_ -> CallbackState
end,
{ok, State#state{callbackstate = CallbackState}}.
-spec parse_request(Packet :: binary()) -> {binary(), binary()}.
parse_request(Packet) ->
Request = binstr:strip(binstr:strip(binstr:strip(binstr:strip(Packet, right, $\n), right, $\r), right, $\s), left, $\s),
case binstr:strchr(Request, $\s) of
0 ->
?log(debug, "got a ~s request~n", [Request]),
{binstr:to_upper(Request), <<>>};
Index ->
Verb = binstr:substr(Request, 1, Index - 1),
Parameters = binstr:strip(binstr:substr(Request, Index + 1), left, $\s),
?log(debug, "got a ~s request with parameters ~s~n", [Verb, Parameters]),
{binstr:to_upper(Verb), Parameters}
end.
-spec handle_request({Verb :: binary(), Args :: binary()}, State :: #state{}) -> {'ok', #state{}} | {'stop', any(), #state{}}.
handle_request({<<>>, _Any}, State) ->
send(State, "500 Error: bad syntax\r\n"),
{ok, State};
handle_request({Command, <<>>}, State)
when Command == <<"HELO">>; Command == <<"EHLO">>; Command == <<"LHLO">> ->
send(State, ["501 Syntax: ", Command, " hostname\r\n"]),
{ok, State};
handle_request({<<"LHLO">>, _Any}, #state{protocol = smtp} = State) ->
send(State, "500 Error: SMTP should send HELO or EHLO instead of LHLO\r\n"),
{ok, State};
handle_request({Msg, _Any}, #state{protocol = lmtp} = State)
when Msg == <<"HELO">>; Msg == <<"EHLO">> ->
send(State, "500 Error: LMTP should replace HELO and EHLO with LHLO\r\n"),
{ok, State};
handle_request({<<"HELO">>, Hostname},
#state{options = Options, module = Module, callbackstate = OldCallbackState} = State) ->
case Module:handle_HELO(Hostname, OldCallbackState) of
{ok, MaxSize, CallbackState} when MaxSize =:= infinity; is_integer(MaxSize) ->
Data = ["250 ", hostname(Options), "\r\n"],
send(State, Data),
{ok, State#state{maxsize = MaxSize,
envelope = #envelope{},
callbackstate = CallbackState}};
{ok, CallbackState} ->
Data = ["250 ", hostname(Options), "\r\n"],
send(State, Data),
{ok, State#state{envelope = #envelope{}, callbackstate = CallbackState}};
{error, Message, CallbackState} ->
send(State, [Message, "\r\n"]),
{ok, State#state{callbackstate = CallbackState}}
end;
handle_request({Msg, Hostname},
#state{options = Options, module = Module, callbackstate = OldCallbackState, tls = Tls} = State)
when Msg == <<"EHLO">>; Msg == <<"LHLO">> ->
case Module:handle_EHLO(Hostname, ?BUILTIN_EXTENSIONS, OldCallbackState) of
{ok, [], CallbackState} ->
Data = ["250 ", hostname(Options), "\r\n"],
send(State, Data),
{ok, State#state{extensions = [], callbackstate = CallbackState}};
{ok, Extensions, CallbackState} ->
ExtensionsUpper = lists:map( fun({X, Y}) -> {string:to_upper(X), Y} end, Extensions),
{Extensions1, MaxSize} = case lists:keyfind("SIZE", 1, ExtensionsUpper) of
{"SIZE", "0"} ->
{lists:keydelete("SIZE", 1, ExtensionsUpper), infinity};
{"SIZE", MaxSizeString} when is_list(MaxSizeString) ->
{ExtensionsUpper, list_to_integer(MaxSizeString)};
false ->
{ExtensionsUpper, State#state.maxsize}
end,
Extensions2 = case Tls of
true ->
lists:delete({"STARTTLS", true}, Extensions1);
false ->
Extensions1
end,
Response = (fun
F([{E, true}]) -> ["250 ", E, "\r\n"];
F([{E, V}]) -> ["250 ", E, " ", V, "\r\n"];
F([Line]) -> ["250 ", Line, "\r\n"];
F([{E, true}|More]) -> ["250-", E, "\r\n" | F(More)];
F([{E, V}|More]) -> ["250-", E, " ", V, "\r\n" | F(More)];
F([Line|More]) -> ["250-", Line, "\r\n" | F(More)]
end)([hostname(Options)|Extensions2]),
%?debugFmt("Respponse ~p~n", [lists:reverse(Response)]),
send(State, Response),
{ok, State#state{extensions = Extensions2, maxsize = MaxSize, envelope = #envelope{}, callbackstate = CallbackState}};
{error, Message, CallbackState} ->
send(State, [Message, "\r\n"]),
{ok, State#state{callbackstate = CallbackState}}
end;
handle_request({<<"AUTH">> = C, _Args}, #state{envelope = undefined, protocol = Protocol} = State) ->
send(State, ["503 Error: send ", lhlo_if_lmtp(Protocol, "EHLO"), " first\r\n"]),
State1 = handle_error(out_of_order, C, State),
{ok, State1};
handle_request({<<"AUTH">>, Args}, #state{extensions = Extensions, envelope = Envelope, options = Options} = State) ->
case binstr:strchr(Args, $\s) of
0 ->
AuthType = Args,
Parameters = false;
Index ->
AuthType = binstr:substr(Args, 1, Index - 1),
Parameters = binstr:strip(binstr:substr(Args, Index + 1), left, $\s)
end,
case has_extension(Extensions, "AUTH") of
false ->
send(State, "502 Error: AUTH not implemented\r\n"),
{ok, State};
{true, AvailableTypes} ->
case lists:member(string:to_upper(binary_to_list(AuthType)),
string:tokens(AvailableTypes, " ")) of
false ->
send(State, "504 Unrecognized authentication type\r\n"),
{ok, State};
true ->
case binstr:to_upper(AuthType) of
<<"LOGIN">> ->
% smtp_socket:send(Socket, "334 " ++ base64:encode_to_string("Username:")),
send(State, "334 VXNlcm5hbWU6\r\n"),
{ok, State#state{waitingauth = 'login', envelope = Envelope#envelope{auth = {<<>>, <<>>}}}};
<<"PLAIN">> when Parameters =/= false ->
% TODO - duplicated below in handle_request waitingauth PLAIN
case binstr:split(base64:decode(Parameters), <<0>>) of
[_Identity, Username, Password] ->
try_auth('plain', Username, Password, State);
[Username, Password] ->
try_auth('plain', Username, Password, State);
_ ->
% TODO error
{ok, State}
end;
<<"PLAIN">> ->
send(State, "334\r\n"),
{ok, State#state{waitingauth = 'plain', envelope = Envelope#envelope{auth = {<<>>, <<>>}}}};
<<"CRAM-MD5">> ->
crypto:start(), % ensure crypto is started, we're gonna need it
String = smtp_util:get_cram_string(hostname(Options)),
send(State, ["334 ", String, "\r\n"]),
{ok, State#state{waitingauth = 'cram-md5', authdata=base64:decode(String), envelope = Envelope#envelope{auth = {<<>>, <<>>}}}}
%"DIGEST-MD5" -> % TODO finish this? (see rfc 2831)
%crypto:start(), % ensure crypto is started, we're gonna need it
%Nonce = get_digest_nonce(),
%Response = io_lib:format("nonce=\"~s\",realm=\"~s\",qop=\"auth\",algorithm=md5-sess,charset=utf-8", Nonce, State#state.hostname),
%smtp_socket:send(Socket, "334 "++Response++"\r\n"),
%{ok, State#state{waitingauth = "DIGEST-MD5", authdata=base64:decode_to_string(Nonce), envelope = Envelope#envelope{auth = {[], []}}}}
end
end
end;
handle_request({<<"MAIL">> = C, _Args}, #state{envelope = undefined, protocol = Protocol} = State) ->
send(State, ["503 Error: send ", lhlo_if_lmtp(Protocol, "HELO/EHLO"), " first\r\n"]),
State1 = handle_error(out_of_order, C, State),
{ok, State1};
handle_request({<<"MAIL">>, Args},
#state{
module = Module, envelope = Envelope0,
callbackstate = OldCallbackState, extensions = Extensions,
maxsize=MaxSize} = State) ->
case Envelope0#envelope.from of
undefined ->
case binstr:strpos(binstr:to_upper(Args), <<"FROM:">>) of
1 ->
Address = binstr:strip(binstr:substr(Args, 6), left, $\s),
case parse_encoded_address(Address, has_extension(Extensions, "SMTPUTF8") =/= false) of
error ->
send(State, "501 Bad sender address syntax\r\n"),
{ok, State};
{ParsedAddress, <<>>} ->
?log(debug, "From address ~s (parsed as ~s)~n", [Address, ParsedAddress]),
case Module:handle_MAIL(ParsedAddress, OldCallbackState) of
{ok, CallbackState} ->
send(State, "250 sender Ok\r\n"),
{ok, State#state{envelope = Envelope0#envelope{from = ParsedAddress}, callbackstate = CallbackState}};
{error, Message, CallbackState} ->
send(State, [Message, "\r\n"]),
{ok, State#state{callbackstate = CallbackState}}
end;
{ParsedAddress, ExtraInfo} ->
?log(debug, "From address ~s (parsed as ~s) with extra info ~s~n", [Address, ParsedAddress, ExtraInfo]),
Options = [binstr:to_upper(X) || X <- binstr:split(ExtraInfo, <<" ">>)],
?log(debug, "options are ~p~n", [Options]),
F = fun(_, {error, Message}) ->
{error, Message};
(<<"SIZE=", Size/binary>>, #state{envelope = Envelope} = InnerState) when MaxSize =:= 'infinity' ->
InnerState#state{envelope = Envelope#envelope{expectedsize = binary_to_integer(Size)}};
(<<"SIZE=", Size/binary>>, #state{envelope = Envelope} = InnerState) ->
case binary_to_integer(Size) > MaxSize of
true ->
{error, ["552 Estimated message length ", Size, " exceeds limit of ", integer_to_binary(MaxSize), "\r\n"]};
false ->
InnerState#state{envelope = Envelope#envelope{expectedsize = binary_to_integer(Size)}}
end;
(<<"BODY=", BodyType/binary>>, #state{envelope = #envelope{flags = Flags} = Envelope} = InnerState) ->
case has_extension(Extensions, "8BITMIME") of
{true, _} ->
Flag = maps:get(BodyType, #{<<"8BITMIME">> => '8bitmime',
<<"7BIT">> => '7bit'}),
InnerState#state{envelope = Envelope#envelope{flags = [Flag | Flags]}};
false ->
{error, "555 Unsupported option BODY\r\n"}
end;
(<<"SMTPUTF8">>, #state{envelope = #envelope{flags = Flags} = Envelope} = InnerState) ->
case has_extension(Extensions, "SMTPUTF8") of
{true, _} ->
InnerState#state{envelope = Envelope#envelope{flags = ['smtputf8' | Flags]}};
false ->
{error, "555 Unsupported option SMTPUTF8\r\n"}
end;
(X, InnerState) ->
case Module:handle_MAIL_extension(X, OldCallbackState) of
{ok, CallbackState} ->
InnerState#state{callbackstate = CallbackState};
error ->
{error, ["555 Unsupported option: ", ExtraInfo, "\r\n"]}
end
end,
case lists:foldl(F, State, Options) of
{error, Message} ->
?log(debug, "error: ~s~n", [Message]),
send(State, Message),
{ok, State};
#state{envelope = Envelope} = NewState ->
?log(debug, "OK~n"),
case Module:handle_MAIL(ParsedAddress, State#state.callbackstate) of
{ok, CallbackState} ->
send(State, "250 sender Ok\r\n"),
{ok, State#state{envelope = Envelope#envelope{from = ParsedAddress}, callbackstate = CallbackState}};
{error, Message, CallbackState} ->
send(State, [Message, "\r\n"]),
{ok, NewState#state{callbackstate = CallbackState}}
end
end
end;
_Else ->
send(State, "501 Syntax: MAIL FROM:<address>\r\n"),
{ok, State}
end;
_Other ->
send(State, "503 Error: Nested MAIL command\r\n"),
{ok, State}
end;
handle_request({<<"RCPT">> = C, _Args}, #state{envelope = undefined} = State) ->
send(State, "503 Error: need MAIL command\r\n"),
State1 = handle_error(out_of_order, C, State),
{ok, State1};
handle_request({<<"RCPT">>, Args}, #state{envelope = Envelope, module = Module, callbackstate = OldCallbackState, extensions = Extensions} = State) ->
case binstr:strpos(binstr:to_upper(Args), <<"TO:">>) of
1 ->
Address = binstr:strip(binstr:substr(Args, 4), left, $\s),
case parse_encoded_address(Address, has_extension(Extensions, "SMTPUTF8") =/= false) of
error ->
send(State, "501 Bad recipient address syntax\r\n"),
{ok, State};
{<<>>, _} ->
% empty rcpt to addresses aren't cool
send(State, "501 Bad recipient address syntax\r\n"),
{ok, State};
{ParsedAddress, <<>>} ->
?log(debug, "To address ~s (parsed as ~s)~n", [Address, ParsedAddress]),
case Module:handle_RCPT(ParsedAddress, OldCallbackState) of
{ok, CallbackState} ->
send(State, "250 recipient Ok\r\n"),
{ok, State#state{envelope = Envelope#envelope{to = Envelope#envelope.to ++ [ParsedAddress]}, callbackstate = CallbackState}};
{error, Message, CallbackState} ->
send(State, [Message, "\r\n"]),
{ok, State#state{callbackstate = CallbackState}}
end;
{ParsedAddress, ExtraInfo} ->
% TODO - are there even any RCPT extensions?
?log(debug, "To address ~s (parsed as ~s) with extra info ~s~n", [Address, ParsedAddress, ExtraInfo]),
send(State, ["555 Unsupported option: ", ExtraInfo, "\r\n"]),
{ok, State}
end;
_Else ->
send(State, "501 Syntax: RCPT TO:<address>\r\n"),
{ok, State}
end;
handle_request({<<"DATA">> = C, <<>>}, #state{envelope = undefined, protocol = Protocol} = State) ->
send(State, ["503 Error: send ", lhlo_if_lmtp(Protocol, "HELO/EHLO"), " first\r\n"]),
State1 = handle_error(out_of_order, C, State),
{ok, State1};
handle_request({<<"DATA">> = C, <<>>}, #state{envelope = Envelope} = State) ->
case {Envelope#envelope.from, Envelope#envelope.to} of
{undefined, _} ->
send(State, "503 Error: need MAIL command\r\n"),
State1 = handle_error(out_of_order, C, State),
{ok, State1};
{_, []} ->
send(State, "503 Error: need RCPT command\r\n"),
State1 = handle_error(out_of_order, C, State),
{ok, State1};
_Else ->
send(State, "354 enter mail, end with line containing only '.'\r\n"),
?log(debug, "switching to data read mode~n", []),
{ok, State#state{readmessage = true}}
end;
handle_request({<<"RSET">>, _Any}, #state{envelope = Envelope, module = Module, callbackstate = OldCallbackState} = State) ->
send(State, "250 Ok\r\n"),
% if the client sends a RSET before a HELO/EHLO don't give them a valid envelope
NewEnvelope = case Envelope of
undefined -> undefined;
_Something -> #envelope{}
end,
{ok, State#state{envelope = NewEnvelope, callbackstate = Module:handle_RSET(OldCallbackState)}};
handle_request({<<"NOOP">>, _Any}, State) ->
send(State, "250 Ok\r\n"),
{ok, State};
handle_request({<<"QUIT">>, _Any}, State) ->
send(State, "221 Bye\r\n"),
{stop, normal, State};
handle_request({<<"VRFY">>, Address}, #state{module= Module, callbackstate = OldCallbackState, extensions = Extensions} = State) ->
case parse_encoded_address(Address, has_extension(Extensions, "SMTPUTF8") =/= false) of
{ParsedAddress, <<>>} ->
case Module:handle_VRFY(ParsedAddress, OldCallbackState) of
{ok, Reply, CallbackState} ->
send(State, ["250 ", Reply, "\r\n"]),
{ok, State#state{callbackstate = CallbackState}};
{error, Message, CallbackState} ->
send(State, [Message, "\r\n"]),
{ok, State#state{callbackstate = CallbackState}}
end;
_Other ->
send(State, "501 Syntax: VRFY username/address\r\n"),
{ok, State}
end;
handle_request({<<"STARTTLS">>, <<>>}, #state{socket = Socket, module = Module, tls=false,
extensions = Extensions, callbackstate = OldCallbackState,
options = Options} = State) ->
case has_extension(Extensions, "STARTTLS") of
{true, _} ->
send(State, "220 OK\r\n"),
TlsOpts0 = proplists:get_value(tls_options, Options, []),
TlsOpts1 = case proplists:get_value(certfile, Options) of
undefined ->
TlsOpts0;
CertFile ->
[{certfile, CertFile} | TlsOpts0]
end,
TlsOpts2 = case proplists:get_value(keyfile, Options) of
undefined ->
TlsOpts1;
KeyFile ->
[{keyfile, KeyFile} | TlsOpts1]
end,
%% Assert that socket is in passive state
{ok, [{active, false}]} = inet:getopts(Socket, [active]),
case ranch_ssl:handshake(Socket, [{packet, line}, {mode, list}, {ssl_imp, new} | TlsOpts2], 5000) of %XXX: see smtp_socket:?SSL_LISTEN_OPTIONS
{ok, NewSocket} ->
?log(debug, "SSL negotiation successful~n"),
ranch_ssl:setopts(NewSocket, [{packet, line}, binary]),
{ok, State#state{socket = NewSocket, transport = ranch_ssl, envelope=undefined,
authdata=undefined, waitingauth=false, readmessage=false,
tls=true, callbackstate = Module:handle_STARTTLS(OldCallbackState)}};
{error, Reason} ->
?log(info, "SSL handshake failed : ~p~n", [Reason]),
send(State, "454 TLS negotiation failed\r\n"),
State1 = handle_error(ssl_handshake_error, Reason, State),
{ok, State1}
end;
false ->
send(State, "500 Command unrecognized\r\n"),
{ok, State}
end;
handle_request({<<"STARTTLS">> = C, <<>>}, State) ->
send(State, "500 TLS already negotiated\r\n"),
State1 = handle_error(out_of_order, C, State),
{ok, State1};
handle_request({<<"STARTTLS">>, _Args}, State) ->
send(State, "501 Syntax error (no parameters allowed)\r\n"),
{ok, State};
handle_request({Verb, Args}, #state{module = Module, callbackstate = OldCallbackState} = State) ->
CallbackState =
case Module:handle_other(Verb, Args, OldCallbackState) of
{noreply, CState1} -> CState1;
{Message, CState1} ->
send(State, [Message, "\r\n"]),
CState1
end,
{ok, State#state{callbackstate = CallbackState}}.
%% @doc handle SASL client response to `334' challenge - RFC-4954
% the client sends a response to auth-cram-md5
handle_sasl(UserDigest, #state{waitingauth = 'cram-md5', envelope = #envelope{auth = {<<>>, <<>>}}, authdata = AuthData} = State) ->
case binstr:split(UserDigest, <<" ">>) of
[Username, Digest] ->
try_auth('cram-md5', Username, {Digest, AuthData}, State#state{authdata=undefined});
_ ->
% TODO error
{ok, State#state{waitingauth=false, authdata=undefined}}
end;
% the client sends a \0username\0password response to auth-plain
handle_sasl(UserPass, #state{waitingauth = 'plain', envelope = #envelope{auth = {<<>>,<<>>}}} = State) ->
case binstr:split(UserPass, <<0>>) of
[_Identity, Username, Password] ->
try_auth('plain', Username, Password, State);
[Username, Password] ->
try_auth('plain', Username, Password, State);
_ ->
% TODO error
{ok, State#state{waitingauth=false}}
end;
% the client sends a username response to auth-login
handle_sasl(Username, #state{waitingauth = 'login', envelope = #envelope{auth = {<<>>,<<>>}}} = State) ->
Envelope = State#state.envelope,
% smtp_socket:send(Socket, "334 " ++ base64:encode_to_string("Password:")),
send(State, "334 UGFzc3dvcmQ6\r\n"),
% store the provided username in envelope.auth
NewState = State#state{envelope = Envelope#envelope{auth = {Username, <<>>}}},
{ok, NewState};
% the client sends a password response to auth-login
handle_sasl(Password, #state{waitingauth = 'login', envelope = #envelope{auth = {Username,<<>>}}} = State) ->
try_auth('login', Username, Password, State).
-spec handle_error(error_class(), any(), #state{}) -> #state{}.
handle_error(Kind, Details, #state{module=Module, callbackstate = OldCallbackState} = State) ->
case erlang:function_exported(Module, handle_error, 3) of
true ->
case Module:handle_error(Kind, Details, OldCallbackState) of
{ok, CallbackState} ->
State#state{callbackstate = CallbackState};
{stop, Reason, CallbackState} ->
throw({stop, Reason, State#state{callbackstate = CallbackState}})
end;
false ->
State
end.
%% pa = parse address
%% ab = angular brackets
-record(pa,
{quotes = false,
ab = true,
utf8 = false}).
%% https://datatracker.ietf.org/doc/html/rfc5321#section-4.1.2
-spec parse_encoded_address(Address :: binary(), Utf8 :: boolean()) -> {binary(), binary()} | 'error'.
parse_encoded_address(<<>>, _) ->
error; % empty
parse_encoded_address(<<"<@", Address/binary>>, Utf8) ->
%% A-d-l (source route) - should be ignored
case binstr:strchr(Address, $:) of
0 ->
error; % invalid address
Index ->
parse_encoded_address(binstr:substr(Address, Index + 1), [], #pa{quotes=false, ab=true, utf8 = Utf8})
end;
parse_encoded_address(<<"<", Address/binary>>, Utf8) ->
parse_encoded_address(Address, [], #pa{quotes=false, ab=true, utf8=Utf8});
parse_encoded_address(<<" ", Address/binary>>, Utf8) ->
parse_encoded_address(Address, Utf8);
parse_encoded_address(Address, Utf8) ->
parse_encoded_address(Address, [], #pa{quotes=false, ab=false, utf8=Utf8}).
-spec parse_encoded_address(Address :: binary(), Acc :: list(), Flags :: #pa{}) -> {binary(), binary()} | 'error'.
parse_encoded_address(<<>>, Acc, #pa{ab = false}) ->
{unicode:characters_to_binary(lists:reverse(Acc)), <<>>};
parse_encoded_address(<<>>, _Acc, #pa{ab = true}) ->
error; % began with angle brackets but didn't end with them
parse_encoded_address(_, Acc, _) when length(Acc) > 320 ->
error; % too long
parse_encoded_address(<<"\\", H, Tail/binary>>, Acc, Flags) ->
parse_encoded_address(Tail, [H | Acc], Flags);
parse_encoded_address(<<"\"", Tail/binary>>, Acc, #pa{quotes = false} = F) ->
parse_encoded_address(Tail, Acc, F#pa{quotes = true});
parse_encoded_address(<<"\"", Tail/binary>>, Acc, #pa{quotes = true} = F) ->
parse_encoded_address(Tail, Acc, F#pa{quotes = false});
parse_encoded_address(<<">", Tail/binary>>, Acc, #pa{quotes = false, ab = true}) ->
{unicode:characters_to_binary(lists:reverse(Acc)), binstr:strip(Tail, left, $\s)};
parse_encoded_address(<<">", _Tail/binary>>, _Acc, #pa{quotes = false, ab = false}) ->
error; % ended with angle brackets but didn't begin with them
parse_encoded_address(<<" ", Tail/binary>>, Acc, #pa{quotes = false, ab = false}) ->
{unicode:characters_to_binary(lists:reverse(Acc)), binstr:strip(Tail, left, $\s)};
parse_encoded_address(<<" ", _Tail/binary>>, _Acc, #pa{quotes = false, ab = true}) ->
error; % began with angle brackets but didn't end with them
parse_encoded_address(<<H/utf8, Tail/binary>>, Acc, #pa{utf8 = true} = F) when H > 127 ->
%% https://datatracker.ietf.org/doc/html/rfc6531#section-3.3
parse_encoded_address(Tail, [H | Acc], F); % UTF-8 above 7bit (when allowed)
parse_encoded_address(<<H, Tail/binary>>, Acc, #pa{quotes = false} = F) when H >= $0, H =< $9 ->
parse_encoded_address(Tail, [H | Acc], F); % digits
parse_encoded_address(<<H, Tail/binary>>, Acc, #pa{quotes = false} = F) when H >= $@, H =< $Z ->
parse_encoded_address(Tail, [H | Acc], F); % @ symbol and uppercase letters
parse_encoded_address(<<H, Tail/binary>>, Acc, #pa{quotes = false} = F) when H >= $a, H =< $z ->
parse_encoded_address(Tail, [H | Acc], F); % lowercase letters
parse_encoded_address(<<H, Tail/binary>>, Acc, #pa{quotes = false} = F) when H =:= $-; H =:= $.; H =:= $_ ->
parse_encoded_address(Tail, [H | Acc], F); % dash, dot, underscore
% Allowed characters in the local name: ! # $ % & ' * + - / = ? ^ _ ` . { | } ~
parse_encoded_address(<<H, Tail/binary>>, Acc, #pa{quotes = false} = F) when H =:= $+;
H =:= $!; H =:= $#; H =:= $$; H =:= $%; H =:= $&; H =:= $'; H =:= $*; H =:= $=;
H =:= $/; H =:= $?; H =:= $^; H =:= $`; H =:= ${; H =:= $|; H =:= $}; H =:= $~ ->
parse_encoded_address(Tail, [H | Acc], F); % other characters
parse_encoded_address(_, _Acc, #pa{quotes = false}) ->
error;
parse_encoded_address(<<H, Tail/binary>>, Acc, #pa{quotes = true} = F) ->
parse_encoded_address(Tail, [H | Acc], F).
-spec has_extension(Extensions :: [{string(), string()}], Extension :: string()) -> {'true', string()} | 'false'.
has_extension(Extensions, Ext) ->
?log(debug, "extensions ~p~n", [Extensions]),
case proplists:get_value(Ext, Extensions) of
undefined ->
false;
Value ->
{true, Value}
end.
-spec try_auth(AuthType :: 'login' | 'plain' | 'cram-md5', Username :: binary(), Credential :: binary() | {binary(), binary()}, State :: #state{}) -> {'ok', #state{}}.
try_auth(AuthType, Username, Credential, #state{module = Module, envelope = Envelope, callbackstate = OldCallbackState} = State) ->
% clear out waiting auth
NewState = State#state{waitingauth = false, envelope = Envelope#envelope{auth = {<<>>, <<>>}}},
case erlang:function_exported(Module, handle_AUTH, 4) of
true ->
case Module:handle_AUTH(AuthType, Username, Credential, OldCallbackState) of
{ok, CallbackState} ->
send(State, "235 Authentication successful.\r\n"),
{ok, NewState#state{callbackstate = CallbackState,
envelope = Envelope#envelope{auth = {Username, Credential}}}};
_Other ->
send(State, "535 Authentication failed.\r\n"),
{ok, NewState}
end;
false ->
?log(warning, "Please define handle_AUTH/4 in your server module or remove AUTH from your module extensions~n"),
send(State, "535 authentication failed (#5.7.1)\r\n"),
{ok, NewState}
end.
%get_digest_nonce() ->
%A = [io_lib:format("~2.16.0b", [X]) || <<X>> <= erlang:md5(integer_to_list(rand:uniform(4294967295)))],
%B = [io_lib:format("~2.16.0b", [X]) || <<X>> <= erlang:md5(integer_to_list(rand:uniform(4294967295)))],
%binary_to_list(base64:encode(lists:flatten(A ++ B))).
%% @doc a tight loop to receive the message body
receive_data(_Acc, _Transport, _Socket, _, Size, MaxSize, Session, _Options) when MaxSize =/= 'infinity', Size > MaxSize ->
?log(info, "SMTP message body size ~B exceeded maximum allowed ~B~n", [Size, MaxSize]),
Session ! {receive_data, {error, size_exceeded}};
receive_data(Acc, Transport, Socket, RecvSize, Size, MaxSize, Session, Options) ->
case Transport:recv(Socket, RecvSize, 1000) of
{ok, Packet} when Acc =:= [] ->
case check_bare_crlf(Packet, <<>>, proplists:get_value(allow_bare_newlines, Options, false), 0) of
error ->
Session ! {receive_data, {error, bare_newline}};
FixedPacket ->
case binstr:strpos(FixedPacket, <<"\r\n.\r\n">>) of
0 ->
?log(debug, "received ~B bytes; size is now ~p~n", [RecvSize, Size + size(Packet)]),
?log(debug, "memory usage: ~p~n", [erlang:process_info(self(), memory)]),
receive_data([FixedPacket | Acc], Transport, Socket, RecvSize, Size + byte_size(FixedPacket), MaxSize, Session, Options);
Index ->
String = binstr:substr(FixedPacket, 1, Index - 1),
Rest = binstr:substr(FixedPacket, Index+5),
?log(debug, "memory usage before flattening: ~p~n", [erlang:process_info(self(), memory)]),
Result = list_to_binary(lists:reverse([String | Acc])),
?log(debug, "memory usage after flattening: ~p~n", [erlang:process_info(self(), memory)]),
Session ! {receive_data, Result, Rest}
end
end;
{ok, Packet} ->
[Last | _] = Acc,
case check_bare_crlf(Packet, Last, proplists:get_value(allow_bare_newlines, Options, false), 0) of
error ->
Session ! {receive_data, {error, bare_newline}};
FixedPacket ->
case binstr:strpos(FixedPacket, <<"\r\n.\r\n">>) of
0 ->
?log(debug, "received ~B bytes; size is now ~p~n", [RecvSize, Size + size(Packet)]),
?log(debug, "memory usage: ~p~n", [erlang:process_info(self(), memory)]),
receive_data([FixedPacket | Acc], Transport, Socket, RecvSize, Size + byte_size(FixedPacket), MaxSize, Session, Options);
Index ->
String = binstr:substr(FixedPacket, 1, Index - 1),
Rest = binstr:substr(FixedPacket, Index+5),
?log(debug, "memory usage before flattening: ~p~n", [erlang:process_info(self(), memory)]),
Result = list_to_binary(lists:reverse([String | Acc])),
?log(debug, "memory usage after flattening: ~p~n", [erlang:process_info(self(), memory)]),
Session ! {receive_data, Result, Rest}
end
end;
{error, timeout} when RecvSize =:= 0, length(Acc) > 1 ->
% check that we didn't accidentally receive a \r\n.\r\n split across 2 receives
[A, B | Acc2] = Acc,
Packet = list_to_binary([B, A]),
case binstr:strpos(Packet, <<"\r\n.\r\n">>) of
0 ->
% uh-oh
?log(debug, "no data on socket, and no DATA terminator, retrying ~p~n", [Session]),
% eventually we'll either get data or a different error, just keep retrying
receive_data(Acc, Transport, Socket, 0, Size, MaxSize, Session, Options);
Index ->
String = binstr:substr(Packet, 1, Index - 1),
Rest = binstr:substr(Packet, Index+5),
?log(debug, "memory usage before flattening: ~p~n", [erlang:process_info(self(), memory)]),
Result = list_to_binary(lists:reverse([String | Acc2])),
?log(debug, "memory usage after flattening: ~p~n", [erlang:process_info(self(), memory)]),
Session ! {receive_data, Result, Rest}
end;
{error, timeout} ->
receive_data(Acc, Transport, Socket, 0, Size, MaxSize, Session, Options);
{error, Reason} ->
?log(warning, "SMTP receive error: ~p", [Reason]),
Session ! {receive_data, {error, Reason}}
end.
check_for_bare_crlf(Bin, Offset) ->
case {re:run(Bin, "(?<!\r)\n", [{capture, none}, {offset, Offset}]), re:run(Bin, "\r(?!\n)", [{capture, none}, {offset, Offset}])} of
{match, _} -> true;
{_, match} -> true;
_ -> false
end.
fix_bare_crlf(Bin, Offset) ->
Options = [{offset, Offset}, {return, binary}, global],
re:replace(re:replace(Bin, "(?<!\r)\n", "\r\n", Options), "\r(?!\n)", "\r\n", Options).
strip_bare_crlf(Bin, Offset) ->
Options = [{offset, Offset}, {return, binary}, global],
re:replace(re:replace(Bin, "(?<!\r)\n", "", Options), "\r(?!\n)", "", Options).
check_bare_crlf(Binary, _, ignore, _) ->
Binary;
check_bare_crlf(<<$\n, _Rest/binary>> = Bin, Prev, Op, 0 = _Offset) when byte_size(Prev) > 0 ->
% check if last character of previous was a CR
Lastchar = binstr:substr(Prev, -1),
case Lastchar of
<<"\r">> ->
% okay, check again for the rest
check_bare_crlf(Bin, <<>>, Op, 1);
_ when Op == false -> % not fixing or ignoring them
error;
_ ->
% no dice
check_bare_crlf(Bin, <<>>, Op, 0)
end;
check_bare_crlf(Binary, _Prev, Op, Offset) ->
Last = binstr:substr(Binary, -1),
% is the last character a CR?
case Last of
<<"\r">> ->
% okay, the last character is a CR, we have to assume the next packet contains the corresponding LF
NewBin = binstr:substr(Binary, 1, byte_size(Binary) -1),
case check_for_bare_crlf(NewBin, Offset) of
true when Op == fix ->
list_to_binary([fix_bare_crlf(NewBin, Offset), "\r"]);
true when Op == strip ->
list_to_binary([strip_bare_crlf(NewBin, Offset), "\r"]);
true ->
error;
false ->
Binary
end;
_ ->
case check_for_bare_crlf(Binary, Offset) of
true when Op == fix ->
fix_bare_crlf(Binary, Offset);
true when Op == strip ->
strip_bare_crlf(Binary, Offset);
true ->
error;
false ->
Binary
end
end.