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)  2007-2018, 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:- use_module(library(ssl)).   38:- use_module(library(socket)).   39:- use_module(library(debug)).   40:- use_module(library(option)).   41:- use_module(library(http/thread_httpd)).   42:- use_module(library(http/http_header)).

   55:- multifile
   56    thread_httpd:make_socket_hook/3,
   57    thread_httpd:accept_hook/2,
   58    thread_httpd:open_client_hook/6,
   59    http:http_protocol_hook/5,
   60    http:open_options/2,
   61    http:http_connection_over_proxy/6,
   62    http:ssl_server_create_hook/3,
   63    http:ssl_server_open_client_hook/3.   64
   65
   66                 /*******************************
   67                 *          SERVER HOOKS        *
   68                 *******************************/

 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

- thread_httpd:accept_hook/2 handles the corresponding accept

   78thread_httpd:make_socket_hook(Port, M:Options0, Options) :-
   79    select(ssl(SSLOptions0), Options0, Options1),
   80    !,
   81    add_secure_ciphers(SSLOptions0, SSLOptions1),
   82    disable_sslv3(SSLOptions1, SSLOptions),
   83    make_socket(Port, Socket, Options1),
   84    ssl_context(server, SSL0, M:SSLOptions),
   85    (   http:ssl_server_create_hook(SSL0, SSL, Options1)
   86    ->  true
   87    ;   SSL = SSL0
   88    ),
   89    atom_concat('httpsd', Port, Queue),
   90    Options = [ queue(Queue),
   91                tcp_socket(Socket),
   92                ssl_instance(SSL)
   93              | Options1
   94              ].

 add_secure_ciphers(+SSLOptions0, -SSLOptions)

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

  100add_secure_ciphers(SSLOptions0, SSLOptions) :-
  101    (   option(cipher_list(_), SSLOptions0)
  102    ->  SSLOptions = SSLOptions0
  103    ;   ssl_secure_ciphers(Ciphers),
  104        SSLOptions = [cipher_list(Ciphers)|SSLOptions0]
  105    ).

 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.

  113disable_sslv3(SSLOptions0, SSLOptions) :-
  114    (   option(min_protocol_version(_), SSLOptions0)
  115    ;   option(disable_ssl_methods(_), SSLOptions0)
  116    ),
  117    !,
  118    SSLOptions = SSLOptions0.
  119disable_sslv3(SSLOptions0,
  120              [ disable_ssl_methods([sslv3,sslv23]), % old OpenSSL versions
  121                min_protocol_version(tlsv1)          % OpenSSL 1.1.0 and later
  122              | SSLOptions0
  123              ]).
  124
  125
  126make_socket(_Port, Socket, Options) :-
  127    option(tcp_socket(Socket), Options),
  128    !.
  129make_socket(Port, Socket, _Options) :-
  130    tcp_socket(Socket),
  131    tcp_setopt(Socket, reuseaddr),
  132    tcp_bind(Socket, Port),
  133    tcp_listen(Socket, 5).

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

Implement the accept for HTTPS connections.

  140thread_httpd:accept_hook(Goal, Options) :-
  141    memberchk(ssl_instance(SSL), Options),
  142    !,
  143    memberchk(queue(Queue), Options),
  144    memberchk(tcp_socket(Socket), Options),
  145    tcp_accept(Socket, Client, Peer),
  146    debug(http(connection), 'New HTTPS connection from ~p', [Peer]),
  147    http_enough_workers(Queue, accept, Peer),
  148    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

  171thread_httpd:open_client_hook(ssl_client(SSL0, Client, Goal, Peer),
  172                              Goal, In, Out,
  173                              [peer(Peer), protocol(https)],
  174                              Options) :-
  175    (   http:ssl_server_open_client_hook(SSL0, SSL1, Options)
  176    ->  true
  177    ;   SSL1 = SSL0
  178    ),
  179    option(timeout(TMO), Options, 60),
  180    tcp_open_socket(Client, Read, Write),
  181    set_stream(Read, timeout(TMO)),
  182    set_stream(Write, timeout(TMO)),
  183    ssl_set_options(SSL1, SSL, [close_parent(true)]),
  184    catch(ssl_negotiate(SSL, Read, Write, In, Out),
  185          E,
  186          ssl_failed(Read, Write, E)).
  187
  188ssl_failed(Read, Write, E) :-
  189    close(Write, [force(true)]),
  190    close(Read,  [force(true)]),
  191    throw(E).
  192
  193
  194                 /*******************************
  195                 *         CLIENT HOOKS         *
  196                 *******************************/

 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. This plugin also passes the default option cacert_file(system(root_certificates)) to ssl_context/3.

  205http:http_protocol_hook(https, Parts, PlainStreamPair, StreamPair, Options) :-
  206    ssl_protocol_hook(Parts, PlainStreamPair, StreamPair, Options).
  207http:http_protocol_hook(wss, Parts, PlainStreamPair, StreamPair, Options) :-
  208    ssl_protocol_hook(Parts, PlainStreamPair, StreamPair, Options).
  209
  210ssl_protocol_hook(Parts, PlainStreamPair, StreamPair, Options) :-
  211    memberchk(host(Host), Parts),
  212    ssl_context(client, SSL, [ host(Host),
  213                               close_parent(true)
  214                             | Options
  215                             ]),
  216    stream_pair(PlainStreamPair, PlainIn, PlainOut),
  217    % if an exception arises, http_open/3 closes the stream for us
  218    ssl_negotiate(SSL, PlainIn, PlainOut, In, Out),
  219    stream_pair(StreamPair, In, Out).

 http:open_options(Parts, Options) is nondet

Implementation of the multifile hook http:open_options/2 used by library(http/http_open). By default, we use the system trusted root certificate database for validating an SSL certificate.

  227http:open_options(Parts, Options) :-
  228    memberchk(scheme(S), Parts),
  229    ssl_scheme(S),
  230    Options = [cacert_file(system(root_certificates))].
  231
  232ssl_scheme(https).
  233ssl_scheme(wss).

 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

  242http:http_connection_over_proxy(proxy(ProxyHost, ProxyPort), Parts,
  243                                Host:Port, StreamPair, Options, Options) :-
  244    memberchk(scheme(https), Parts),
  245    !,
  246    tcp_connect(ProxyHost:ProxyPort, StreamPair, [bypass_proxy(true)]),
  247    catch(negotiate_http_connect(StreamPair, Host:Port),
  248          Error,
  249          ( close(StreamPair, [force(true)]),
  250            throw(Error)
  251          )).
  252
  253negotiate_http_connect(StreamPair, Address):-
  254    format(StreamPair, 'CONNECT ~w HTTP/1.1\r\n\r\n', [Address]),
  255    flush_output(StreamPair),
  256    http_read_reply_header(StreamPair, Header),
  257    memberchk(status(_, Status, Message), Header),
  258    (   Status == ok
  259    ->  true
  260    ;   throw(error(proxy_rejection(Message), _))
  261    )