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source: protocols/jabber/sasl.c @ 87dddee

Last change on this file since 87dddee was 911d97a, checked in by Wilmer van der Gaast <wilmer@…>, at 2011-08-04T15:19:54Z

Error handling fixes.

Found one double free() bug causing troubles when a buddy_msg() handler takes
down the IM connection immediately.

Property mode set to 100644

File size: 14.5 KB

Line
1	/***************************************************************************\
2	* *
3	* BitlBee - An IRC to IM gateway *
4	* Jabber module - SASL authentication *
5	* *
6	* Copyright 2006 Wilmer van der Gaast <wilmer@gaast.net> *
7	* *
8	* This program is free software; you can redistribute it and/or modify *
9	* it under the terms of the GNU General Public License as published by *
10	* the Free Software Foundation; either version 2 of the License, or *
11	* (at your option) any later version. *
12	* *
13	* This program is distributed in the hope that it will be useful, *
14	* but WITHOUT ANY WARRANTY; without even the implied warranty of *
15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
16	* GNU General Public License for more details. *
17	* *
18	* You should have received a copy of the GNU General Public License along *
19	* with this program; if not, write to the Free Software Foundation, Inc., *
20	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. *
21	* *
22	\***************************************************************************/
23
24	#include <ctype.h>
25
26	#include "jabber.h"
27	#include "base64.h"
28	#include "oauth2.h"
29	#include "oauth.h"
30
31	xt_status sasl_pkt_mechanisms( struct xt_node *node, gpointer data )
32	{
33	struct im_connection *ic = data;
34	struct jabber_data *jd = ic->proto_data;
35	struct xt_node c, reply;
36	char *s;
37	int sup_plain = 0, sup_digest = 0, sup_oauth2 = 0, sup_fb = 0;
38
39	if( !sasl_supported( ic ) )
40	{
41	/* Should abort this now, since we should already be doing
42	IQ authentication. Strange things happen when you try
43	to do both... */
44	imcb_log( ic, "XMPP 1.0 non-compliant server seems to support SASL, please report this as a BitlBee bug!" );
45	return XT_HANDLED;
46	}
47
48	s = xt_find_attr( node, "xmlns" );
49	if( !s \|\| strcmp( s, XMLNS_SASL ) != 0 )
50	{
51	imcb_log( ic, "Stream error while authenticating" );
52	imc_logout( ic, FALSE );
53	return XT_ABORT;
54	}
55
56	c = node->children;
57	while( ( c = xt_find_node( c, "mechanism" ) ) )
58	{
59	if( c->text && g_strcasecmp( c->text, "PLAIN" ) == 0 )
60	sup_plain = 1;
61	if( c->text && g_strcasecmp( c->text, "DIGEST-MD5" ) == 0 )
62	sup_digest = 1;
63	if( c->text && g_strcasecmp( c->text, "X-OAUTH2" ) == 0 )
64	sup_oauth2 = 1;
65	if( c->text && g_strcasecmp( c->text, "X-FACEBOOK-PLATFORM" ) == 0 )
66	sup_fb = 1;
67
68	c = c->next;
69	}
70
71	if( !sup_plain && !sup_digest )
72	{
73	imcb_error( ic, "No known SASL authentication schemes supported" );
74	imc_logout( ic, FALSE );
75	return XT_ABORT;
76	}
77
78	reply = xt_new_node( "auth", NULL, NULL );
79	xt_add_attr( reply, "xmlns", XMLNS_SASL );
80
81	if( set_getbool( &ic->acc->set, "oauth" ) )
82	{
83	int len;
84
85	if( !sup_oauth2 )
86	{
87	imcb_error( ic, "OAuth requested, but not supported by server" );
88	imc_logout( ic, FALSE );
89	xt_free_node( reply );
90	return XT_ABORT;
91	}
92
93	/* X-OAUTH2 is, not the standard OAuth2 SASL/XMPP implementation.
94	It's currently used by GTalk and vaguely documented on
95	http://code.google.com/apis/cloudprint/docs/rawxmpp.html . */
96	xt_add_attr( reply, "mechanism", "X-OAUTH2" );
97
98	len = strlen( jd->username ) + strlen( jd->oauth2_access_token ) + 2;
99	s = g_malloc( len + 1 );
100	s[0] = 0;
101	strcpy( s + 1, jd->username );
102	strcpy( s + 2 + strlen( jd->username ), jd->oauth2_access_token );
103	reply->text = base64_encode( (unsigned char *)s, len );
104	reply->text_len = strlen( reply->text );
105	g_free( s );
106	}
107	else if( sup_fb && strstr( ic->acc->pass, "session_key=" ) )
108	{
109	xt_add_attr( reply, "mechanism", "X-FACEBOOK-PLATFORM" );
110	jd->flags \|= JFLAG_SASL_FB;
111	}
112	else if( sup_digest )
113	{
114	xt_add_attr( reply, "mechanism", "DIGEST-MD5" );
115
116	/* The rest will be done later, when we receive a <challenge/>. */
117	}
118	else if( sup_plain )
119	{
120	int len;
121
122	xt_add_attr( reply, "mechanism", "PLAIN" );
123
124	/* With SASL PLAIN in XMPP, the text should be b64(\0user\0pass) */
125	len = strlen( jd->username ) + strlen( ic->acc->pass ) + 2;
126	s = g_malloc( len + 1 );
127	s[0] = 0;
128	strcpy( s + 1, jd->username );
129	strcpy( s + 2 + strlen( jd->username ), ic->acc->pass );
130	reply->text = base64_encode( (unsigned char *)s, len );
131	reply->text_len = strlen( reply->text );
132	g_free( s );
133	}
134
135	if( reply && !jabber_write_packet( ic, reply ) )
136	{
137	xt_free_node( reply );
138	return XT_ABORT;
139	}
140	xt_free_node( reply );
141
142	/* To prevent classic authentication from happening. */
143	jd->flags \|= JFLAG_STREAM_STARTED;
144
145	return XT_HANDLED;
146	}
147
148	/* Non-static function, but not mentioned in jabber.h because it's for internal
149	use, just that the unittest should be able to reach it... */
150	char sasl_get_part( char data, char *field )
151	{
152	int i, len;
153
154	len = strlen( field );
155
156	while( isspace( data ) \|\| data == ',' )
157	data ++;
158
159	if( g_strncasecmp( data, field, len ) == 0 && data[len] == '=' )
160	{
161	i = strlen( field ) + 1;
162	}
163	else
164	{
165	for( i = 0; data[i]; i ++ )
166	{
167	/* If we have a ", skip until it's closed again. */
168	if( data[i] == '"' )
169	{
170	i ++;
171	while( data[i] != '"' \|\| data[i-1] == '\\' )
172	i ++;
173	}
174
175	/* If we got a comma, we got a new field. Check it,
176	find the next key after it. */
177	if( data[i] == ',' )
178	{
179	while( isspace( data[i] ) \|\| data[i] == ',' )
180	i ++;
181
182	if( g_strncasecmp( data + i, field, len ) == 0 &&
183	data[i+len] == '=' )
184	{
185	i += len + 1;
186	break;
187	}
188	}
189	}
190	}
191
192	if( data[i] == '"' )
193	{
194	int j;
195	char *ret;
196
197	i ++;
198	len = 0;
199	while( data[i+len] != '"' \|\| data[i+len-1] == '\\' )
200	len ++;
201
202	ret = g_strndup( data + i, len );
203	for( i = j = 0; ret[i]; i ++ )
204	{
205	if( ret[i] == '\\' )
206	{
207	ret[j++] = ret[++i];
208	}
209	else
210	{
211	ret[j++] = ret[i];
212	}
213	}
214	ret[j] = 0;
215
216	return ret;
217	}
218	else if( data[i] )
219	{
220	len = 0;
221	while( data[i+len] && data[i+len] != ',' )
222	len ++;
223
224	return g_strndup( data + i, len );
225	}
226	else
227	{
228	return NULL;
229	}
230	}
231
232	xt_status sasl_pkt_challenge( struct xt_node *node, gpointer data )
233	{
234	struct im_connection *ic = data;
235	struct jabber_data *jd = ic->proto_data;
236	struct xt_node *reply_pkt = NULL;
237	char nonce = NULL, realm = NULL, *cnonce = NULL;
238	unsigned char cnonce_bin[30];
239	char *digest_uri = NULL;
240	char *dec = NULL;
241	char s = NULL, reply = NULL;
242	xt_status ret = XT_ABORT;
243
244	if( node->text_len == 0 )
245	goto error;
246
247	dec = frombase64( node->text );
248
249	if( jd->flags & JFLAG_SASL_FB )
250	{
251	/* Facebook proprietary authentication. Not as useful as it seemed, but
252	the code's written now, may as well keep it..
253
254	Mechanism is described on http://developers.facebook.com/docs/chat/
255	and in their Python module. It's all mostly useless because the tokens
256	expire after 24h. */
257	GSList p_in = NULL, p_out = NULL, *p;
258	md5_state_t md5;
259	char time[33], *token;
260	const char *secret;
261
262	oauth_params_parse( &p_in, dec );
263	oauth_params_add( &p_out, "nonce", oauth_params_get( &p_in, "nonce" ) );
264	oauth_params_add( &p_out, "method", oauth_params_get( &p_in, "method" ) );
265	oauth_params_free( &p_in );
266
267	token = g_strdup( ic->acc->pass );
268	oauth_params_parse( &p_in, token );
269	g_free( token );
270	oauth_params_add( &p_out, "session_key", oauth_params_get( &p_in, "session_key" ) );
271
272	g_snprintf( time, sizeof( time ), "%lld", (long long) ( gettime() * 1000 ) );
273	oauth_params_add( &p_out, "call_id", time );
274	oauth_params_add( &p_out, "api_key", oauth2_service_facebook.consumer_key );
275	oauth_params_add( &p_out, "v", "1.0" );
276	oauth_params_add( &p_out, "format", "XML" );
277
278	md5_init( &md5 );
279	for( p = p_out; p; p = p->next )
280	md5_append( &md5, p->data, strlen( p->data ) );
281
282	secret = oauth_params_get( &p_in, "secret" );
283	if( secret )
284	md5_append( &md5, (unsigned char*) secret, strlen( secret ) );
285	md5_finish_ascii( &md5, time );
286	oauth_params_add( &p_out, "sig", time );
287
288	reply = oauth_params_string( p_out );
289	oauth_params_free( &p_out );
290	oauth_params_free( &p_in );
291	}
292	else if( !( s = sasl_get_part( dec, "rspauth" ) ) )
293	{
294	/* See RFC 2831 for for information. */
295	md5_state_t A1, A2, H;
296	md5_byte_t A1r[16], A2r[16], Hr[16];
297	char A1h[33], A2h[33], Hh[33];
298	int i;
299
300	nonce = sasl_get_part( dec, "nonce" );
301	realm = sasl_get_part( dec, "realm" );
302
303	if( !nonce )
304	goto error;
305
306	/* Jabber.Org considers the realm part optional and doesn't
307	specify one. Oh well, actually they're right, but still,
308	don't know if this is right... */
309	if( !realm )
310	realm = g_strdup( jd->server );
311
312	random_bytes( cnonce_bin, sizeof( cnonce_bin ) );
313	cnonce = base64_encode( cnonce_bin, sizeof( cnonce_bin ) );
314	digest_uri = g_strdup_printf( "%s/%s", "xmpp", jd->server );
315
316	/* Generate the MD5 hash of username:realm:password,
317	I decided to call it H. */
318	md5_init( &H );
319	s = g_strdup_printf( "%s:%s:%s", jd->username, realm, ic->acc->pass );
320	md5_append( &H, (unsigned char *) s, strlen( s ) );
321	g_free( s );
322	md5_finish( &H, Hr );
323
324	/* Now generate the hex. MD5 hash of H:nonce:cnonce, called A1. */
325	md5_init( &A1 );
326	s = g_strdup_printf( ":%s:%s", nonce, cnonce );
327	md5_append( &A1, Hr, 16 );
328	md5_append( &A1, (unsigned char *) s, strlen( s ) );
329	g_free( s );
330	md5_finish( &A1, A1r );
331	for( i = 0; i < 16; i ++ )
332	sprintf( A1h + i * 2, "%02x", A1r[i] );
333
334	/* A2... */
335	md5_init( &A2 );
336	s = g_strdup_printf( "%s:%s", "AUTHENTICATE", digest_uri );
337	md5_append( &A2, (unsigned char *) s, strlen( s ) );
338	g_free( s );
339	md5_finish( &A2, A2r );
340	for( i = 0; i < 16; i ++ )
341	sprintf( A2h + i * 2, "%02x", A2r[i] );
342
343	/* Final result: A1:nonce:00000001:cnonce:auth:A2. Let's reuse H for it. */
344	md5_init( &H );
345	s = g_strdup_printf( "%s:%s:%s:%s:%s:%s", A1h, nonce, "00000001", cnonce, "auth", A2h );
346	md5_append( &H, (unsigned char *) s, strlen( s ) );
347	g_free( s );
348	md5_finish( &H, Hr );
349	for( i = 0; i < 16; i ++ )
350	sprintf( Hh + i * 2, "%02x", Hr[i] );
351
352	/* Now build the SASL response string: */
353	reply = g_strdup_printf( "username=\"%s\",realm=\"%s\",nonce=\"%s\",cnonce=\"%s\","
354	"nc=%08x,qop=auth,digest-uri=\"%s\",response=%s,charset=%s",
355	jd->username, realm, nonce, cnonce, 1, digest_uri, Hh, "utf-8" );
356	}
357	else
358	{
359	/* We found rspauth, but don't really care... */
360	}
361
362	s = reply ? tobase64( reply ) : NULL;
363	reply_pkt = xt_new_node( "response", s, NULL );
364	xt_add_attr( reply_pkt, "xmlns", XMLNS_SASL );
365
366	if( !jabber_write_packet( ic, reply_pkt ) )
367	goto silent_error;
368
369	ret = XT_HANDLED;
370	goto silent_error;
371
372	error:
373	imcb_error( ic, "Incorrect SASL challenge received" );
374	imc_logout( ic, FALSE );
375
376	silent_error:
377	g_free( digest_uri );
378	g_free( cnonce );
379	g_free( nonce );
380	g_free( reply );
381	g_free( realm );
382	g_free( dec );
383	g_free( s );
384	xt_free_node( reply_pkt );
385
386	return ret;
387	}
388
389	xt_status sasl_pkt_result( struct xt_node *node, gpointer data )
390	{
391	struct im_connection *ic = data;
392	struct jabber_data *jd = ic->proto_data;
393	char *s;
394
395	s = xt_find_attr( node, "xmlns" );
396	if( !s \|\| strcmp( s, XMLNS_SASL ) != 0 )
397	{
398	imcb_log( ic, "Stream error while authenticating" );
399	imc_logout( ic, FALSE );
400	return XT_ABORT;
401	}
402
403	if( strcmp( node->name, "success" ) == 0 )
404	{
405	imcb_log( ic, "Authentication finished" );
406	jd->flags \|= JFLAG_AUTHENTICATED \| JFLAG_STREAM_RESTART;
407	}
408	else if( strcmp( node->name, "failure" ) == 0 )
409	{
410	imcb_error( ic, "Authentication failure" );
411	imc_logout( ic, FALSE );
412	return XT_ABORT;
413	}
414
415	return XT_HANDLED;
416	}
417
418	/* This one is needed to judge if we'll do authentication using IQ or SASL.
419	It's done by checking if the <stream:stream> from the server has a
420	version attribute. I don't know if this is the right way though... */
421	gboolean sasl_supported( struct im_connection *ic )
422	{
423	struct jabber_data *jd = ic->proto_data;
424
425	return ( jd->xt && jd->xt->root && xt_find_attr( jd->xt->root, "version" ) ) != 0;
426	}
427
428	void sasl_oauth2_init( struct im_connection *ic )
429	{
430	char msg, url;
431
432	imcb_log( ic, "Starting OAuth authentication" );
433
434	/* Temporary contact, just used to receive the OAuth response. */
435	imcb_add_buddy( ic, "jabber_oauth", NULL );
436	url = oauth2_url( &oauth2_service_google,
437	"https://www.googleapis.com/auth/googletalk" );
438	msg = g_strdup_printf( "Open this URL in your browser to authenticate: %s", url );
439	imcb_buddy_msg( ic, "jabber_oauth", msg, 0, 0 );
440	imcb_buddy_msg( ic, "jabber_oauth", "Respond to this message with the returned "
441	"authorization token.", 0, 0 );
442
443	g_free( msg );
444	g_free( url );
445	}
446
447	static gboolean sasl_oauth2_remove_contact( gpointer data, gint fd, b_input_condition cond )
448	{
449	struct im_connection *ic = data;
450	if( g_slist_find( jabber_connections, ic ) )
451	imcb_remove_buddy( ic, "jabber_oauth", NULL );
452	return FALSE;
453	}
454
455	static void sasl_oauth2_got_token( gpointer data, const char access_token, const char refresh_token );
456
457	int sasl_oauth2_get_refresh_token( struct im_connection ic, const char msg )
458	{
459	char *code;
460	int ret;
461
462	imcb_log( ic, "Requesting OAuth access token" );
463
464	/* Don't do it here because the caller may get confused if the contact
465	we're currently sending a message to is deleted. */
466	b_timeout_add( 1, sasl_oauth2_remove_contact, ic );
467
468	code = g_strdup( msg );
469	g_strstrip( code );
470	ret = oauth2_access_token( &oauth2_service_google, OAUTH2_AUTH_CODE,
471	code, sasl_oauth2_got_token, ic );
472
473	g_free( code );
474	return ret;
475	}
476
477	int sasl_oauth2_refresh( struct im_connection ic, const char refresh_token )
478	{
479	return oauth2_access_token( &oauth2_service_google, OAUTH2_AUTH_REFRESH,
480	refresh_token, sasl_oauth2_got_token, ic );
481	}
482
483	static void sasl_oauth2_got_token( gpointer data, const char access_token, const char refresh_token )
484	{
485	struct im_connection *ic = data;
486	struct jabber_data *jd;
487
488	if( g_slist_find( jabber_connections, ic ) == NULL )
489	return;
490
491	jd = ic->proto_data;
492
493	if( access_token == NULL )
494	{
495	imcb_error( ic, "OAuth failure (missing access token)" );
496	imc_logout( ic, TRUE );
497	return;
498	}
499	if( refresh_token != NULL )
500	{
501	g_free( ic->acc->pass );
502	ic->acc->pass = g_strdup_printf( "refresh_token=%s", refresh_token );
503	}
504
505	g_free( jd->oauth2_access_token );
506	jd->oauth2_access_token = g_strdup( access_token );
507
508	jabber_connect( ic );
509	}

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