1/*  Part of SWI-Prolog
    2
    3    Author:        Jan Wielemaker
    4    E-mail:        J.Wielemaker@vu.nl
    5    WWW:           http://www.swi-prolog.org
    6    Copyright (c)  2007-2020, University of Amsterdam
    7                              VU University Amsterdam
    8    All rights reserved.
    9
   10    Redistribution and use in source and binary forms, with or without
   11    modification, are permitted provided that the following conditions
   12    are met:
   13
   14    1. Redistributions of source code must retain the above copyright
   15       notice, this list of conditions and the following disclaimer.
   16
   17    2. Redistributions in binary form must reproduce the above copyright
   18       notice, this list of conditions and the following disclaimer in
   19       the documentation and/or other materials provided with the
   20       distribution.
   21
   22    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   23    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   24    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   25    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   26    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   27    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   28    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   29    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
   30    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   32    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   33    POSSIBILITY OF SUCH DAMAGE.
   34*/
   35
   36:- module(http_ssl_plugin, []).   37% Requires ssl:upgrade_legacy_options/2 hook
   38:- use_module(library(ssl),
   39              [ ssl_context/3,
   40                ssl_secure_ciphers/1,
   41                ssl_property/2,
   42                ssl_set_options/3,
   43                ssl_negotiate/5
   44              ]).   45:- use_module(library(debug),[debug/3]).   46:- use_module(library(socket),
   47              [ tcp_socket/1,
   48                tcp_setopt/2,
   49                tcp_bind/2,
   50                tcp_listen/2,
   51                tcp_accept/3,
   52                tcp_open_socket/3,
   53                tcp_connect/3
   54              ]).   55
   56:- autoload(library(lists),[select/3]).   57:- autoload(library(option),[option/2,option/3]).   58:- autoload(library(apply), [include/3]).   59:- autoload(library(http/http_header),[http_read_reply_header/2]).   60:- autoload(library(http/thread_httpd),[http_enough_workers/3]).

   73:- multifile
   74    thread_httpd:make_socket_hook/3,
   75    thread_httpd:accept_hook/2,
   76    thread_httpd:open_client_hook/6,
   77    http:http_protocol_hook/5,
   78    http:open_options/2,
   79    http:http_connection_over_proxy/6,
   80    http:ssl_server_create_hook/3,
   81    http:ssl_server_open_client_hook/3.   82
   83
   84                 /*******************************
   85                 *          SERVER HOOKS        *
   86                 *******************************/

 thread_httpd:make_socket_hook(?Port, :OptionsIn, -OptionsOut) is semidet

Hook into http_server/2 to create an SSL server if the option ssl(SSLOptions) is provided.

See also

- accept_hook/2 handles the corresponding accept

   96thread_httpd:make_socket_hook(Port, M:Options0, Options) :-
   97    select(ssl(SSLOptions0), Options0, Options1),
   98    !,
   99    add_secure_ciphers(SSLOptions0, SSLOptions1),
  100    disable_sslv3(SSLOptions1, SSLOptions),
  101    make_socket(Port, Socket, Options1),
  102    ssl_context(server, SSL0, M:[close_parent(true)|SSLOptions]),
  103    (   http:ssl_server_create_hook(SSL0, SSL1, Options1)
  104    ->  ensure_close_parent(SSL1, SSL)
  105    ;   SSL = SSL0
  106    ),
  107    atom_concat('httpsd', Port, Queue),
  108    Options = [ queue(Queue),
  109                tcp_socket(Socket),
  110                ssl_instance(SSL)
  111              | Options1
  112              ].
  113
  114ensure_close_parent(SSL0, SSL) :-
  115    (   ssl_property(SSL0, close_parent(true))
  116    ->  SSL = SSL0
  117    ;   ssl_set_options(SSL0, SSL, [close_parent(true)])
  118    ).

 add_secure_ciphers(+SSLOptions0, -SSLOptions)

Add ciphers from ssl_secure_ciphers/1 if no ciphers are provided.

  124add_secure_ciphers(SSLOptions0, SSLOptions) :-
  125    (   option(cipher_list(_), SSLOptions0)
  126    ->  SSLOptions = SSLOptions0
  127    ;   ssl_secure_ciphers(Ciphers),
  128        SSLOptions = [cipher_list(Ciphers)|SSLOptions0]
  129    ).

 disable_sslv3(+SSLOptions0, -SSLOptions)

Disable SSLv3, which is considered insecure unless the caller specifies the allowed versions explicitly, so we assume s/he knows what s/he is doing.

  137disable_sslv3(SSLOptions0, SSLOptions) :-
  138    (   option(min_protocol_version(_), SSLOptions0)
  139    ;   option(disable_ssl_methods(_), SSLOptions0)
  140    ),
  141    !,
  142    SSLOptions = SSLOptions0.
  143disable_sslv3(SSLOptions0,
  144              [ disable_ssl_methods([sslv3,sslv23]), % old OpenSSL versions
  145                min_protocol_version(tlsv1)          % OpenSSL 1.1.0 and later
  146              | SSLOptions0
  147              ]).
  148
  149
  150make_socket(_Port, Socket, Options) :-
  151    option(tcp_socket(Socket), Options),
  152    !.
  153make_socket(Port, Socket, _Options) :-
  154    tcp_socket(Socket),
  155    tcp_setopt(Socket, reuseaddr),
  156    tcp_bind(Socket, Port),
  157    tcp_listen(Socket, 5).

 thread_httpd:accept_hook(:Goal, +Options) is semidet

Implement the accept for HTTPS connections.

  164thread_httpd:accept_hook(Goal, Options) :-
  165    memberchk(ssl_instance(SSL0), Options),
  166    !,
  167    memberchk(queue(Queue), Options),
  168    memberchk(tcp_socket(Socket), Options),
  169    tcp_accept(Socket, Client, Peer),
  170    debug(http(connection), 'New HTTPS connection from ~p', [Peer]),
  171    http_enough_workers(Queue, accept, Peer),
  172    ensure_close_parent(SSL0, SSL),
  173    thread_send_message(Queue, ssl_client(SSL, Client, Goal, Peer)).

 http:ssl_server_create_hook(+SSL0, -SSL, +Options) is semidet

Extensible predicate that is called once after creating an HTTPS server. If this predicate succeeds, SSL is the context that is used for negotiating new connections. Otherwise, SSL0 is used, which is the context that was created with the given options.

See also

- ssl_context/3 for creating an SSL context

 http:ssl_server_open_client_hook(+SSL0, -SSL, +Options) is semidet

Extensible predicate that is called before each connection that the server negotiates with a client. If this predicate succeeds, SSL is the context that is used for the new connection. Otherwise, SSL0 is used, which is the context that was created when launching the server.

See also

- ssl_context/3 for creating an SSL context

  196thread_httpd:open_client_hook(ssl_client(SSL0, Client, Goal, Peer),
  197                              Goal, In, Out,
  198                              [peer(Peer), protocol(https)],
  199                              Options) :-
  200    (   http:ssl_server_open_client_hook(SSL0, SSL, Options)
  201    ->  true
  202    ;   SSL = SSL0
  203    ),
  204    option(timeout(TMO), Options, 60),
  205    tcp_open_socket(Client, Read, Write),
  206    set_stream(Read, timeout(TMO)),
  207    set_stream(Write, timeout(TMO)),
  208    catch(ssl_negotiate(SSL, Read, Write, In, Out),
  209          E,
  210          ssl_failed(Read, Write, E)).
  211
  212ssl_failed(Read, Write, E) :-
  213    close(Write, [force(true)]),
  214    close(Read,  [force(true)]),
  215    throw(E).
  216
  217
  218                 /*******************************
  219                 *         CLIENT HOOKS         *
  220                 *******************************/

 http:http_protocol_hook(+Scheme, +Parts, +PlainStreamPair, -StreamPair, +Options) is semidet

Hook for http_open/3 to connect to an HTTPS (SSL-based HTTP) server.

  228http:http_protocol_hook(https, Parts, PlainStreamPair, StreamPair, Options) :-
  229    ssl_protocol_hook(Parts, PlainStreamPair, StreamPair, Options).
  230http:http_protocol_hook(wss, Parts, PlainStreamPair, StreamPair, Options) :-
  231    ssl_protocol_hook(Parts, PlainStreamPair, StreamPair, Options).
  232
  233ssl_protocol_hook(Parts, PlainStreamPair, StreamPair, Options) :-
  234    memberchk(host(Host), Parts),
  235    include(ssl_option, Options, SSLOptions),
  236    ssl_context(client, SSL, [ host(Host),
  237                               close_parent(true)
  238                             | SSLOptions
  239                             ]),
  240    stream_pair(PlainStreamPair, PlainIn, PlainOut),
  241    % if an exception arises, http_open/3 closes the stream for us
  242    ssl_negotiate(SSL, PlainIn, PlainOut, In, Out),
  243    stream_pair(StreamPair, In, Out).
  244
  245% Might be better to be more  selective,   but  passing the options from
  246% http_open/3 with more than 1 argument makes ssl_context/3 fail.
  247
  248ssl_option(Term) :-
  249    compound(Term),
  250    compound_name_arity(Term, _, 1).

 http:http_connection_over_proxy(+Proxy, +Parts, +HostPort, -StreamPair, +OptionsIn, -OptionsOut)

Facilitate an HTTPS connection via a proxy using HTTP CONNECT. Note that most proxies will only support this for connecting on port 443

  259http:http_connection_over_proxy(proxy(ProxyHost, ProxyPort), Parts,
  260                                Host:Port, StreamPair, Options, Options) :-
  261    memberchk(scheme(https), Parts),
  262    !,
  263    tcp_connect(ProxyHost:ProxyPort, StreamPair, [bypass_proxy(true)]),
  264    catch(negotiate_http_connect(StreamPair, Host:Port),
  265          Error,
  266          ( close(StreamPair, [force(true)]),
  267            throw(Error)
  268          )).
  269
  270negotiate_http_connect(StreamPair, Address):-
  271    format(StreamPair, 'CONNECT ~w HTTP/1.1\r\n\r\n', [Address]),
  272    flush_output(StreamPair),
  273    http_read_reply_header(StreamPair, Header),
  274    memberchk(status(_, Status, Message), Header),
  275    (   Status == ok
  276    ->  true
  277    ;   throw(error(proxy_rejection(Message), _))
  278    )