/*
* This file is part of DisOrder.
- * Copyright (C) 2004, 2005, 2007 Richard Kettlewell
+ * Copyright (C) 2004, 2005, 2007, 2008 Richard Kettlewell
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
#include "dcgi.h"
#include "url.h"
+/** @brief Return true if @p a is better than @p b
+ *
+ * NB. We don't bother checking if the path is right, we merely check for the
+ * longest path. This isn't a security hole: if the browser wants to send us
+ * bad cookies it's quite capable of sending just the right path anyway. The
+ * point of choosing the longest path is to avoid using a cookie set by another
+ * CGI script which shares a path prefix with us, which would allow it to
+ * maliciously log users out.
+ *
+ * Such a script could still "maliciously" log someone in, if it had acquired a
+ * suitable cookie. But it could just log in directly if it had that, so there
+ * is no obvious vulnerability here either.
+ */
+static int better_cookie(const struct cookie *a, const struct cookie *b) {
+ if(a->path && b->path)
+ /* If both have a path then the one with the longest path is best */
+ return strlen(a->path) > strlen(b->path);
+ else if(a->path)
+ /* If only @p a has a path then it is better */
+ return 1;
+ else
+ /* If neither have a path, or if only @p b has a path, then @p b is
+ * better */
+ return 0;
+}
+
int main(int argc, char **argv) {
const char *cookie_env, *conf;
dcgi_global g;
dcgi_state s;
cgi_sink output;
- int n;
+ int n, best_cookie;
struct cookiedata cd;
if(argc > 0) progname = argv[0];
+ /* RFC 3875 s8.2 recommends rejecting PATH_INFO if we don't make use of
+ * it. */
+ if(getenv("PATH_INFO")) {
+ printf("Content-Type: text/html\n");
+ printf("Status: 404\n");
+ printf("\n");
+ printf("<p>Sorry, PATH_INFO not supported.</p>\n");
+ exit(0);
+ }
cgi_parse();
if((conf = getenv("DISORDER_CONFIG"))) configfile = xstrdup(conf);
if(getenv("DISORDER_DEBUG")) debugging = 1;
if(cookie_env) {
/* This will be an HTTP header */
if(!parse_cookie(cookie_env, &cd)) {
- for(n = 0; n < cd.ncookies
- && strcmp(cd.cookies[n].name, "disorder"); ++n)
- ;
- if(n < cd.ncookies)
- login_cookie = cd.cookies[n].value;
- }
+ /* Pick the best available cookie from all those offered */
+ best_cookie = -1;
+ for(n = 0; n < cd.ncookies; ++n) {
+ /* Is this the right cookie? */
+ if(strcmp(cd.cookies[n].name, "disorder"))
+ continue;
+ /* Is it better than anything we've seen so far? */
+ if(best_cookie < 0
+ || better_cookie(&cd.cookies[n], &cd.cookies[best_cookie]))
+ best_cookie = n;
+ }
+ if(best_cookie != -1)
+ login_cookie = cd.cookies[best_cookie].value;
+ } else
+ error(0, "could not parse cookie field '%s'", cookie_env);
}
disorder_cgi_login(&s, &output);
- /* TODO RFC 3875 s8.2 recommendations e.g. concerning PATH_INFO */
disorder_cgi(&output, &s);
if(fclose(stdout) < 0) fatal(errno, "error closing stdout");
return 0;
Local Variables:
c-basic-offset:2
comment-column:40
+fill-column:79
+indent-tabs-mode:nil
End:
*/