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Commit	Line	Data
	1	/*
	2	* This file is part of DisOrder.
	3	* Copyright (C) 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
	21	#include "disorder-cgi.h"
	22
	23	/** @brief Client used by CGI
	24	*
	25	* The caller should arrange for this to be created before any of
	26	* these expansions are used (if it cannot connect then it's safe to
	27	* leave it as NULL).
	28	*/
	29	disorder_client *dcgi_client;
	30
	31	/** @brief Return true if @p a is better than @p b
	32	*
	33	* NB. We don't bother checking if the path is right, we merely check for the
	34	* longest path. This isn't a security hole: if the browser wants to send us
	35	* bad cookies it's quite capable of sending just the right path anyway. The
	36	* point of choosing the longest path is to avoid using a cookie set by another
	37	* CGI script which shares a path prefix with us, which would allow it to
	38	* maliciously log users out.
	39	*
	40	* Such a script could still "maliciously" log someone in, if it had acquired a
	41	* suitable cookie. But it could just log in directly if it had that, so there
	42	* is no obvious vulnerability here either.
	43	*/
	44	static int better_cookie(const struct cookie a, const struct cookie b) {
	45	if(a->path && b->path)
	46	/* If both have a path then the one with the longest path is best */
	47	return strlen(a->path) > strlen(b->path);
	48	else if(a->path)
	49	/* If only @p a has a path then it is better */
	50	return 1;
	51	else
	52	/* If neither have a path, or if only @p b has a path, then @p b is
	53	* better */
	54	return 0;
	55	}
	56
	57	/** @brief Login cookie */
	58	char *dcgi_cookie;
	59
	60	/** @brief Set @ref login_cookie */
	61	void dcgi_get_cookie(void) {
	62	const char *cookie_env;
	63	int n, best_cookie;
	64	struct cookiedata cd;
	65
	66	/* See if there's a cookie */
	67	cookie_env = getenv("HTTP_COOKIE");
	68	if(cookie_env) {
	69	/* This will be an HTTP header */
	70	if(!parse_cookie(cookie_env, &cd)) {
	71	/* Pick the best available cookie from all those offered */
	72	best_cookie = -1;
	73	for(n = 0; n < cd.ncookies; ++n) {
	74	/* Is this the right cookie? */
	75	if(strcmp(cd.cookies[n].name, "disorder"))
	76	continue;
	77	/* Is it better than anything we've seen so far? */
	78	if(best_cookie < 0
	79	\|\| better_cookie(&cd.cookies[n], &cd.cookies[best_cookie]))
	80	best_cookie = n;
	81	}
	82	if(best_cookie != -1)
	83	dcgi_cookie = cd.cookies[best_cookie].value;
	84	} else
	85	error(0, "could not parse cookie field '%s'", cookie_env);
	86	}
	87	}
	88
	89	/** @brief Return a Cookie: header */
	90	char *dcgi_cookie_header(void) {
	91	struct dynstr d[1];
	92	struct url u;
	93	char *s;
	94
	95	memset(&u, 0, sizeof u);
	96	dynstr_init(d);
	97	parse_url(config->url, &u);
	98	if(dcgi_cookie) {
	99	dynstr_append_string(d, "disorder=");
	100	dynstr_append_string(d, dcgi_cookie);
	101	} else {
	102	/* Force browser to discard cookie */
	103	dynstr_append_string(d, "disorder=none;Max-Age=0");
	104	}
	105	if(u.path) {
	106	/* The default domain matches the request host, so we need not override
	107	* that. But the default path only goes up to the rightmost /, which would
	108	* cause the browser to expose the cookie to other CGI programs on the same
	109	* web server. */
	110	dynstr_append_string(d, ";Version=1;Path=");
	111	/* Formally we are supposed to quote the path, since it invariably has a
	112	* slash in it. However Safari does not parse quoted paths correctly, so
	113	* this won't work. Fortunately nothing else seems to care about proper
	114	* quoting of paths, so in practice we get with it. (See also
	115	* parse_cookie() where we are liberal about cookie paths on the way back
	116	* in.) */
	117	dynstr_append_string(d, u.path);
	118	}
	119	dynstr_terminate(d);
	120	byte_xasprintf(&s, "Set-Cookie: %s", d->vec);
	121	return s;
	122	}
	123
	124	/** @brief Log in as the current user or guest if none */
	125	void dcgi_login(void) {
	126	/* Junk old data */
	127	dcgi_lookup_reset();
	128	/* Junk the old connection if there is one */
	129	if(dcgi_client)
	130	disorder_close(dcgi_client);
	131	/* Create a new connection */
	132	dcgi_client = disorder_new(0);
	133	/* Reconnect */
	134	if(disorder_connect_cookie(dcgi_client, dcgi_cookie)) {
	135	dcgi_error("connect");
	136	exit(0);
	137	}
	138	/* If there was a cookie but it went bad, we forget it */
	139	if(dcgi_cookie && !strcmp(disorder_user(dcgi_client), "guest"))
	140	dcgi_cookie = 0;
	141	}
	142
	143	/*
	144	Local Variables:
	145	c-basic-offset:2
	146	comment-column:40
	147	fill-column:79
	148	indent-tabs-mode:nil
	149	End:
	150	*/