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source: protocols/jabber/sasl.c @ d74c644

Last change on this file since d74c644 was 501b4e0, checked in by Wilmer van der Gaast <wilmer@…>, at 2006-10-02T16:42:32Z
Added a useful error message for SASL negotiation failures and turned off the little hack in jabber_write() for now because it breaks error handling.
Property mode set to `100644`
File size: 9.0 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 "jabber.h"
25	#include "base64.h"
26
27	#define SASL_NS "urn:ietf:params:xml:ns:xmpp-sasl"
28
29	xt_status sasl_pkt_mechanisms( struct xt_node *node, gpointer data )
30	{
31	struct gaim_connection *gc = data;
32	struct jabber_data *jd = gc->proto_data;
33	struct xt_node c, reply;
34	char *s;
35	int sup_plain = 0, sup_digest = 0;
36
37	if( !sasl_supported( gc ) )
38	{
39	/* Should abort this now, since we should already be doing
40	IQ authentication. Strange things happen when you try
41	to do both... */
42	serv_got_crap( gc, "XMPP 1.0 non-compliant server seems to support SASL, please report this as a BitlBee bug!" );
43	return XT_HANDLED;
44	}
45
46	s = xt_find_attr( node, "xmlns" );
47	if( !s \|\| strcmp( s, SASL_NS ) != 0 )
48	{
49	signoff( gc );
50	return XT_ABORT;
51	}
52
53	c = node->children;
54	while( ( c = xt_find_node( c, "mechanism" ) ) )
55	{
56	if( c->text && g_strcasecmp( c->text, "PLAIN" ) == 0 )
57	sup_plain = 1;
58	if( c->text && g_strcasecmp( c->text, "DIGEST-MD5" ) == 0 )
59	sup_digest = 1;
60
61	c = c->next;
62	}
63
64	if( !sup_plain && !sup_digest )
65	{
66	hide_login_progress( gc, "No known SASL authentication schemes supported" );
67	signoff( gc );
68	return XT_ABORT;
69	}
70
71	reply = xt_new_node( "auth", NULL, NULL );
72	xt_add_attr( reply, "xmlns", SASL_NS );
73
74	if( sup_digest )
75	{
76	xt_add_attr( reply, "mechanism", "DIGEST-MD5" );
77
78	/* The rest will be done later, when we receive a <challenge/>. */
79	}
80	else if( sup_plain )
81	{
82	int len;
83
84	xt_add_attr( reply, "mechanism", "PLAIN" );
85
86	/* With SASL PLAIN in XMPP, the text should be b64(\0user\0pass) */
87	len = strlen( jd->username ) + strlen( gc->acc->pass ) + 2;
88	s = g_malloc( len + 1 );
89	s[0] = 0;
90	strcpy( s + 1, jd->username );
91	strcpy( s + 2 + strlen( jd->username ), gc->acc->pass );
92	reply->text = base64_encode( s, len );
93	reply->text_len = strlen( reply->text );
94	g_free( s );
95	}
96
97	if( !jabber_write_packet( gc, reply ) )
98	{
99	xt_free_node( reply );
100	return XT_ABORT;
101	}
102	xt_free_node( reply );
103
104	/* To prevent classic authentication from happening. */
105	jd->flags \|= JFLAG_STREAM_STARTED;
106
107	return XT_HANDLED;
108	}
109
110	static char sasl_get_part( char data, char *field )
111	{
112	int i, len;
113
114	len = strlen( field );
115
116	if( g_strncasecmp( data, field, len ) == 0 && data[len] == '=' )
117	{
118	i = strlen( field ) + 1;
119	}
120	else
121	{
122	for( i = 0; data[i]; i ++ )
123	{
124	/* If we have a ", skip until it's closed again. */
125	if( data[i] == '"' )
126	{
127	i ++;
128	while( data[i] != '"' \|\| data[i-1] == '\\' )
129	i ++;
130	}
131
132	/* If we got a comma, we got a new field. Check it. */
133	if( data[i] == ',' &&
134	g_strncasecmp( data + i + 1, field, len ) == 0 &&
135	data[i+len+1] == '=' )
136	{
137	i += len + 2;
138	break;
139	}
140	}
141	}
142
143	if( data[i] == '"' )
144	{
145	int j;
146	char *ret;
147
148	i ++;
149	len = 0;
150	while( data[i+len] != '"' \|\| data[i+len-1] == '\\' )
151	len ++;
152
153	ret = g_strndup( data + i, len );
154	for( i = j = 0; ret[i]; i ++ )
155	{
156	if( ret[i] == '\\' )
157	{
158	ret[j++] = ret[++i];
159	}
160	else
161	{
162	ret[j++] = ret[i];
163	}
164	}
165	ret[j] = 0;
166
167	return ret;
168	}
169	else if( data[i] )
170	{
171	len = 0;
172	while( data[i+len] && data[i+len] != ',' )
173	len ++;
174
175	return g_strndup( data + i, len );
176	}
177	else
178	{
179	return NULL;
180	}
181	}
182
183	xt_status sasl_pkt_challenge( struct xt_node *node, gpointer data )
184	{
185	struct gaim_connection *gc = data;
186	struct jabber_data *jd = gc->proto_data;
187	struct xt_node *reply = NULL;
188	char nonce = NULL, realm = NULL, *cnonce = NULL, cnonce_bin[30];
189	char *digest_uri = NULL;
190	char *dec = NULL;
191	char *s = NULL;
192	xt_status ret = XT_ABORT;
193
194	if( node->text_len == 0 )
195	goto error;
196
197	dec = frombase64( node->text );
198
199	if( !( s = sasl_get_part( dec, "rspauth" ) ) )
200	{
201	/* See RFC 2831 for for information. */
202	md5_state_t A1, A2, H;
203	md5_byte_t A1r[16], A2r[16], Hr[16];
204	char A1h[33], A2h[33], Hh[33];
205	int i;
206
207	nonce = sasl_get_part( dec, "nonce" );
208	realm = sasl_get_part( dec, "realm" );
209
210	if( !nonce )
211	goto error;
212
213	/* Jabber.Org considers the realm part optional and doesn't
214	specify one. Oh well, actually they're right, but still,
215	don't know if this is right... */
216	if( !realm )
217	realm = g_strdup( jd->server );
218
219	random_bytes( (unsigned char *) cnonce_bin, sizeof( cnonce_bin ) );
220	cnonce = base64_encode( cnonce_bin, sizeof( cnonce_bin ) );
221	digest_uri = g_strdup_printf( "%s/%s", "xmpp", jd->server );
222
223	/* Generate the MD5 hash of username:realm:password,
224	I decided to call it H. */
225	md5_init( &H );
226	s = g_strdup_printf( "%s:%s:%s", jd->username, realm, gc->acc->pass );
227	md5_append( &H, (unsigned char *) s, strlen( s ) );
228	g_free( s );
229	md5_finish( &H, Hr );
230
231	/* Now generate the hex. MD5 hash of H:nonce:cnonce, called A1. */
232	md5_init( &A1 );
233	s = g_strdup_printf( ":%s:%s", nonce, cnonce );
234	md5_append( &A1, Hr, 16 );
235	md5_append( &A1, (unsigned char *) s, strlen( s ) );
236	g_free( s );
237	md5_finish( &A1, A1r );
238	for( i = 0; i < 16; i ++ )
239	sprintf( A1h + i * 2, "%02x", A1r[i] );
240
241	/* A2... */
242	md5_init( &A2 );
243	s = g_strdup_printf( "%s:%s", "AUTHENTICATE", digest_uri );
244	md5_append( &A2, (unsigned char *) s, strlen( s ) );
245	g_free( s );
246	md5_finish( &A2, A2r );
247	for( i = 0; i < 16; i ++ )
248	sprintf( A2h + i * 2, "%02x", A2r[i] );
249
250	/* Final result: A1:nonce:00000001:cnonce:auth:A2. Let's reuse H for it. */
251	md5_init( &H );
252	s = g_strdup_printf( "%s:%s:%s:%s:%s:%s", A1h, nonce, "00000001", cnonce, "auth", A2h );
253	md5_append( &H, (unsigned char *) s, strlen( s ) );
254	g_free( s );
255	md5_finish( &H, Hr );
256	for( i = 0; i < 16; i ++ )
257	sprintf( Hh + i * 2, "%02x", Hr[i] );
258
259	/* Now build the SASL response string: */
260	g_free( dec );
261	dec = g_strdup_printf( "username=\"%s\",realm=\"%s\",nonce=\"%s\",cnonce=\"%s\","
262	"nc=%08x,qop=auth,digest-uri=\"%s\",response=%s,charset=%s",
263	jd->username, realm, nonce, cnonce, 1, digest_uri, Hh, "utf-8" );
264	s = tobase64( dec );
265	}
266	else
267	{
268	/* We found rspauth, but don't really care... */
269	g_free( s );
270	s = NULL;
271	}
272
273	reply = xt_new_node( "response", s, NULL );
274	xt_add_attr( reply, "xmlns", SASL_NS );
275
276	if( !jabber_write_packet( gc, reply ) )
277	goto silent_error;
278
279	ret = XT_HANDLED;
280	goto silent_error;
281
282	error:
283	hide_login_progress( gc, "Incorrect SASL challenge received" );
284	signoff( gc );
285
286	silent_error:
287	g_free( digest_uri );
288	g_free( cnonce );
289	g_free( nonce );
290	g_free( realm );
291	g_free( dec );
292	g_free( s );
293	xt_free_node( reply );
294
295	return ret;
296	}
297
298	xt_status sasl_pkt_result( struct xt_node *node, gpointer data )
299	{
300	struct gaim_connection *gc = data;
301	struct jabber_data *jd = gc->proto_data;
302	char *s;
303
304	s = xt_find_attr( node, "xmlns" );
305	if( !s \|\| strcmp( s, SASL_NS ) != 0 )
306	{
307	signoff( gc );
308	return XT_ABORT;
309	}
310
311	if( strcmp( node->name, "success" ) == 0 )
312	{
313	set_login_progress( gc, 1, "Authentication finished" );
314	jd->flags \|= JFLAG_AUTHENTICATED \| JFLAG_STREAM_RESTART;
315	}
316	else if( strcmp( node->name, "failure" ) == 0 )
317	{
318	hide_login_progress( gc, "Authentication failure" );
319	signoff( gc );
320	return XT_ABORT;
321	}
322
323	return XT_HANDLED;
324	}
325
326	/* This one is needed to judge if we'll do authentication using IQ or SASL.
327	It's done by checking if the <stream:stream> from the server has a
328	version attribute. I don't know if this is the right way though... */
329	gboolean sasl_supported( struct gaim_connection *gc )
330	{
331	struct jabber_data *jd = gc->proto_data;
332
333	return ( (void*) ( jd->xt && jd->xt->root && xt_find_attr( jd->xt->root, "version" ) ) ) != NULL;
334	}

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