mdw@git.distorted.org.uk Git - disorder/blob - server/cgimain.c

   1 /*
   2  * This file is part of DisOrder.
   3  * Copyright (C) 2004, 2005, 2007, 2008 Richard Kettlewell
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  18  * USA
  19  */
  20 /** @file server/cgimain.c
  21  * @brief DisOrder CGI
  22  */
  23
  24 #include <config.h>
  25 #include "types.h"
  26
  27 #include <stdio.h>
  28 #include <errno.h>
  29 #include <stdlib.h>
  30 #include <sys/types.h>
  31 #include <sys/socket.h>
  32 #include <locale.h>
  33 #include <string.h>
  34 #include <stdarg.h>
  35
  36 #include "client.h"
  37 #include "sink.h"
  38 #include "hash.h"
  39 #include "mem.h"
  40 #include "log.h"
  41 #include "configuration.h"
  42 #include "disorder.h"
  43 #include "api-client.h"
  44 #include "mime.h"
  45 #include "printf.h"
  46 #include "url.h"
  47 #include "macros.h"
  48 #include "macros-disorder.h"
  49 #include "cgi.h"
  50 #include "actions.h"
  51 #include "defs.h"
  52
  53 /** @brief Return true if @p a is better than @p b
  54  *
  55  * NB. We don't bother checking if the path is right, we merely check for the
  56  * longest path.  This isn't a security hole: if the browser wants to send us
  57  * bad cookies it's quite capable of sending just the right path anyway.  The
  58  * point of choosing the longest path is to avoid using a cookie set by another
  59  * CGI script which shares a path prefix with us, which would allow it to
  60  * maliciously log users out.
  61  *
  62  * Such a script could still "maliciously" log someone in, if it had acquired a
  63  * suitable cookie.  But it could just log in directly if it had that, so there
  64  * is no obvious vulnerability here either.
  65  */
  66 static int better_cookie(const struct cookie *a, const struct cookie *b) {
  67   if(a->path && b->path)
  68     /* If both have a path then the one with the longest path is best */
  69     return strlen(a->path) > strlen(b->path);
  70   else if(a->path)
  71     /* If only @p a has a path then it is better */
  72     return 1;
  73   else
  74     /* If neither have a path, or if only @p b has a path, then @p b is
  75      * better */
  76     return 0;
  77 }
  78
  79 int main(int argc, char **argv) {
  80   const char *cookie_env, *conf;
  81   int n, best_cookie;
  82   struct cookiedata cd;
  83
  84   if(argc > 0)
  85     progname = argv[0];
  86   /* RFC 3875 s8.2 recommends rejecting PATH_INFO if we don't make use of
  87    * it. */
  88   if(getenv("PATH_INFO")) {
  89     /* TODO it might be nice to link back to the right place... */
  90     printf("Content-Type: text/html\n");
  91     printf("Status: 404\n");
  92     printf("\n");
  93     printf("<p>Sorry, PATH_INFO not supported.</p>\n");
  94     exit(0);
  95   }
  96   cgi_init();
  97   /* We allow various things to be overridden from the environment.  This is
  98    * intended for debugging and is not a documented feature. */
  99   if((conf = getenv("DISORDER_CONFIG")))
 100     configfile = xstrdup(conf);
 101   if(getenv("DISORDER_DEBUG"))
 102     debugging = 1;
 103   if(config_read(0))
 104     exit(EXIT_FAILURE);
 105   /* Figure out our URL.  This can still be overridden from the config file if
 106    * necessary but it shouldn't be necessary in ordinary installations. */
 107   if(!config->url)
 108     config->url = infer_url();
 109   /* See if there's a cookie */
 110   cookie_env = getenv("HTTP_COOKIE");
 111   if(cookie_env) {
 112     /* This will be an HTTP header */
 113     if(!parse_cookie(cookie_env, &cd)) {
 114       /* Pick the best available cookie from all those offered */
 115       best_cookie = -1;
 116       for(n = 0; n < cd.ncookies; ++n) {
 117         /* Is this the right cookie? */
 118         if(strcmp(cd.cookies[n].name, "disorder"))
 119           continue;
 120         /* Is it better than anything we've seen so far? */
 121         if(best_cookie < 0
 122            || better_cookie(&cd.cookies[n], &cd.cookies[best_cookie]))
 123           best_cookie = n;
 124       }
 125       if(best_cookie != -1)
 126         login_cookie = cd.cookies[best_cookie].value;
 127     } else
 128       error(0, "could not parse cookie field '%s'", cookie_env);
 129   }
 130   /* Register expansions */
 131   mx_register_builtin();
 132   register_disorder_expansions();
 133   /* Update search path.  We look in the config directory first and the data
 134    * directory second, so that the latter overrides the former. */
 135   mx_search_path(pkgconfdir);
 136   mx_search_path(pkgdatadir);
 137   /* Never cache anythging */
 138   if(printf("Cache-Control: no-cache\n") < 0)
 139     fatal(errno, "error writing to stdout");
 140   /* Create the initial connection, trying the cookie if we found a suitable
 141    * one. */
 142   disorder_cgi_login();
 143   /* The main program... */
 144   disorder_cgi_action(NULL);
 145   /* In practice if a write fails that probably means the web server went away,
 146    * but we log it anyway. */
 147   if(fclose(stdout) < 0)
 148     fatal(errno, "error closing stdout");
 149   return 0;
 150 }
 151
 152 /*
 153 Local Variables:
 154 c-basic-offset:2
 155 comment-column:40
 156 fill-column:79
 157 indent-tabs-mode:nil
 158 End:
 159 */