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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

Rev	Line
[5997488]	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
[8d74291]	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
[5997488]	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	{
[501b4e0]	66	hide_login_progress( gc, "No known SASL authentication schemes supported" );
[5997488]	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
[d8e0484]	74	if( sup_digest )
[fe7a554]	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 )
[5997488]	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
[d8e0484]	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
[5997488]	183	xt_status sasl_pkt_challenge( struct xt_node *node, gpointer data )
	184	{
[d8e0484]	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
[d9282b4]	210	if( !nonce )
[d8e0484]	211	goto error;
	212
[d9282b4]	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
[d8e0484]	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;
[5997488]	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	}
[8d74291]	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
[fe7a554]	333	return ( (void*) ( jd->xt && jd->xt->root && xt_find_attr( jd->xt->root, "version" ) ) ) != NULL;
[8d74291]	334	}

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