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source: protocols/jabber/sasl.c @ f9756bd

Last change on this file since f9756bd was af97b23, checked in by Wilmer van der Gaast <wilmer@…>, at 2008-02-16T13:17:52Z
Improved sasl_get_part() to deal with whitespace in challenge strings, as described in RFC 2831 secion 7.1 (the #rule description). Closes bug #362.
Property mode set to `100644`
File size: 9.4 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
[af97b23]	24	#include <ctype.h>
	25
[5997488]	26	#include "jabber.h"
	27	#include "base64.h"
	28
	29	xt_status sasl_pkt_mechanisms( struct xt_node *node, gpointer data )
	30	{
[0da65d5]	31	struct im_connection *ic = data;
	32	struct jabber_data *jd = ic->proto_data;
[5997488]	33	struct xt_node c, reply;
	34	char *s;
	35	int sup_plain = 0, sup_digest = 0;
	36
[0da65d5]	37	if( !sasl_supported( ic ) )
[8d74291]	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... */
[84b045d]	42	imcb_log( ic, "XMPP 1.0 non-compliant server seems to support SASL, please report this as a BitlBee bug!" );
[8d74291]	43	return XT_HANDLED;
	44	}
	45
[5997488]	46	s = xt_find_attr( node, "xmlns" );
[47d3ac4]	47	if( !s \|\| strcmp( s, XMLNS_SASL ) != 0 )
[5997488]	48	{
[84b045d]	49	imcb_log( ic, "Stream error while authenticating" );
[c2fb3809]	50	imc_logout( ic, FALSE );
[5997488]	51	return XT_ABORT;
	52	}
	53
	54	c = node->children;
	55	while( ( c = xt_find_node( c, "mechanism" ) ) )
	56	{
	57	if( c->text && g_strcasecmp( c->text, "PLAIN" ) == 0 )
	58	sup_plain = 1;
	59	if( c->text && g_strcasecmp( c->text, "DIGEST-MD5" ) == 0 )
	60	sup_digest = 1;
	61
	62	c = c->next;
	63	}
	64
	65	if( !sup_plain && !sup_digest )
	66	{
[84b045d]	67	imcb_error( ic, "No known SASL authentication schemes supported" );
[c2fb3809]	68	imc_logout( ic, FALSE );
[5997488]	69	return XT_ABORT;
	70	}
	71
	72	reply = xt_new_node( "auth", NULL, NULL );
[47d3ac4]	73	xt_add_attr( reply, "xmlns", XMLNS_SASL );
[5997488]	74
[d8e0484]	75	if( sup_digest )
[fe7a554]	76	{
	77	xt_add_attr( reply, "mechanism", "DIGEST-MD5" );
	78
	79	/* The rest will be done later, when we receive a <challenge/>. */
	80	}
	81	else if( sup_plain )
[5997488]	82	{
	83	int len;
	84
	85	xt_add_attr( reply, "mechanism", "PLAIN" );
	86
	87	/* With SASL PLAIN in XMPP, the text should be b64(\0user\0pass) */
[0da65d5]	88	len = strlen( jd->username ) + strlen( ic->acc->pass ) + 2;
[5997488]	89	s = g_malloc( len + 1 );
	90	s[0] = 0;
	91	strcpy( s + 1, jd->username );
[0da65d5]	92	strcpy( s + 2 + strlen( jd->username ), ic->acc->pass );
[3b6eadc]	93	reply->text = base64_encode( (unsigned char *)s, len );
[5997488]	94	reply->text_len = strlen( reply->text );
	95	g_free( s );
	96	}
	97
[0da65d5]	98	if( !jabber_write_packet( ic, reply ) )
[5997488]	99	{
	100	xt_free_node( reply );
	101	return XT_ABORT;
	102	}
	103	xt_free_node( reply );
	104
	105	/* To prevent classic authentication from happening. */
	106	jd->flags \|= JFLAG_STREAM_STARTED;
	107
	108	return XT_HANDLED;
	109	}
	110
[af97b23]	111	/* Non-static function, but not mentioned in jabber.h because it's for internal
	112	use, just that the unittest should be able to reach it... */
	113	char sasl_get_part( char data, char *field )
[d8e0484]	114	{
	115	int i, len;
	116
	117	len = strlen( field );
	118
[af97b23]	119	while( isspace( data ) \|\| data == ',' )
	120	data ++;
	121
[d8e0484]	122	if( g_strncasecmp( data, field, len ) == 0 && data[len] == '=' )
	123	{
	124	i = strlen( field ) + 1;
	125	}
	126	else
	127	{
	128	for( i = 0; data[i]; i ++ )
	129	{
	130	/* If we have a ", skip until it's closed again. */
	131	if( data[i] == '"' )
	132	{
	133	i ++;
	134	while( data[i] != '"' \|\| data[i-1] == '\\' )
	135	i ++;
	136	}
	137
[af97b23]	138	/* If we got a comma, we got a new field. Check it,
	139	find the next key after it. */
	140	if( data[i] == ',' )
[d8e0484]	141	{
[af97b23]	142	while( isspace( data[i] ) \|\| data[i] == ',' )
	143	i ++;
	144
	145	if( g_strncasecmp( data + i, field, len ) == 0 &&
	146	data[i+len] == '=' )
	147	{
	148	i += len + 1;
	149	break;
	150	}
[d8e0484]	151	}
	152	}
	153	}
	154
	155	if( data[i] == '"' )
	156	{
	157	int j;
	158	char *ret;
	159
	160	i ++;
	161	len = 0;
	162	while( data[i+len] != '"' \|\| data[i+len-1] == '\\' )
	163	len ++;
	164
	165	ret = g_strndup( data + i, len );
	166	for( i = j = 0; ret[i]; i ++ )
	167	{
	168	if( ret[i] == '\\' )
	169	{
	170	ret[j++] = ret[++i];
	171	}
	172	else
	173	{
	174	ret[j++] = ret[i];
	175	}
	176	}
	177	ret[j] = 0;
	178
	179	return ret;
	180	}
	181	else if( data[i] )
	182	{
	183	len = 0;
	184	while( data[i+len] && data[i+len] != ',' )
	185	len ++;
	186
	187	return g_strndup( data + i, len );
	188	}
	189	else
	190	{
	191	return NULL;
	192	}
	193	}
	194
[5997488]	195	xt_status sasl_pkt_challenge( struct xt_node *node, gpointer data )
	196	{
[0da65d5]	197	struct im_connection *ic = data;
	198	struct jabber_data *jd = ic->proto_data;
[d8e0484]	199	struct xt_node *reply = NULL;
[3b6eadc]	200	char nonce = NULL, realm = NULL, *cnonce = NULL;
	201	unsigned char cnonce_bin[30];
[d8e0484]	202	char *digest_uri = NULL;
	203	char *dec = NULL;
	204	char *s = NULL;
	205	xt_status ret = XT_ABORT;
	206
	207	if( node->text_len == 0 )
	208	goto error;
	209
	210	dec = frombase64( node->text );
	211
	212	if( !( s = sasl_get_part( dec, "rspauth" ) ) )
	213	{
	214	/* See RFC 2831 for for information. */
	215	md5_state_t A1, A2, H;
	216	md5_byte_t A1r[16], A2r[16], Hr[16];
	217	char A1h[33], A2h[33], Hh[33];
	218	int i;
	219
	220	nonce = sasl_get_part( dec, "nonce" );
	221	realm = sasl_get_part( dec, "realm" );
	222
[d9282b4]	223	if( !nonce )
[d8e0484]	224	goto error;
	225
[d9282b4]	226	/* Jabber.Org considers the realm part optional and doesn't
	227	specify one. Oh well, actually they're right, but still,
	228	don't know if this is right... */
	229	if( !realm )
	230	realm = g_strdup( jd->server );
	231
[3b6eadc]	232	random_bytes( cnonce_bin, sizeof( cnonce_bin ) );
[d8e0484]	233	cnonce = base64_encode( cnonce_bin, sizeof( cnonce_bin ) );
	234	digest_uri = g_strdup_printf( "%s/%s", "xmpp", jd->server );
	235
	236	/* Generate the MD5 hash of username:realm:password,
	237	I decided to call it H. */
	238	md5_init( &H );
[0da65d5]	239	s = g_strdup_printf( "%s:%s:%s", jd->username, realm, ic->acc->pass );
[d8e0484]	240	md5_append( &H, (unsigned char *) s, strlen( s ) );
	241	g_free( s );
	242	md5_finish( &H, Hr );
	243
	244	/* Now generate the hex. MD5 hash of H:nonce:cnonce, called A1. */
	245	md5_init( &A1 );
	246	s = g_strdup_printf( ":%s:%s", nonce, cnonce );
	247	md5_append( &A1, Hr, 16 );
	248	md5_append( &A1, (unsigned char *) s, strlen( s ) );
	249	g_free( s );
	250	md5_finish( &A1, A1r );
	251	for( i = 0; i < 16; i ++ )
	252	sprintf( A1h + i * 2, "%02x", A1r[i] );
	253
	254	/* A2... */
	255	md5_init( &A2 );
	256	s = g_strdup_printf( "%s:%s", "AUTHENTICATE", digest_uri );
	257	md5_append( &A2, (unsigned char *) s, strlen( s ) );
	258	g_free( s );
	259	md5_finish( &A2, A2r );
	260	for( i = 0; i < 16; i ++ )
	261	sprintf( A2h + i * 2, "%02x", A2r[i] );
	262
	263	/* Final result: A1:nonce:00000001:cnonce:auth:A2. Let's reuse H for it. */
	264	md5_init( &H );
	265	s = g_strdup_printf( "%s:%s:%s:%s:%s:%s", A1h, nonce, "00000001", cnonce, "auth", A2h );
	266	md5_append( &H, (unsigned char *) s, strlen( s ) );
	267	g_free( s );
	268	md5_finish( &H, Hr );
	269	for( i = 0; i < 16; i ++ )
	270	sprintf( Hh + i * 2, "%02x", Hr[i] );
	271
	272	/* Now build the SASL response string: */
	273	g_free( dec );
	274	dec = g_strdup_printf( "username=\"%s\",realm=\"%s\",nonce=\"%s\",cnonce=\"%s\","
	275	"nc=%08x,qop=auth,digest-uri=\"%s\",response=%s,charset=%s",
	276	jd->username, realm, nonce, cnonce, 1, digest_uri, Hh, "utf-8" );
	277	s = tobase64( dec );
	278	}
	279	else
	280	{
	281	/* We found rspauth, but don't really care... */
	282	g_free( s );
	283	s = NULL;
	284	}
	285
	286	reply = xt_new_node( "response", s, NULL );
[47d3ac4]	287	xt_add_attr( reply, "xmlns", XMLNS_SASL );
[d8e0484]	288
[0da65d5]	289	if( !jabber_write_packet( ic, reply ) )
[d8e0484]	290	goto silent_error;
	291
	292	ret = XT_HANDLED;
	293	goto silent_error;
	294
	295	error:
[84b045d]	296	imcb_error( ic, "Incorrect SASL challenge received" );
[c2fb3809]	297	imc_logout( ic, FALSE );
[d8e0484]	298
	299	silent_error:
	300	g_free( digest_uri );
	301	g_free( cnonce );
	302	g_free( nonce );
	303	g_free( realm );
	304	g_free( dec );
	305	g_free( s );
	306	xt_free_node( reply );
	307
	308	return ret;
[5997488]	309	}
	310
	311	xt_status sasl_pkt_result( struct xt_node *node, gpointer data )
	312	{
[0da65d5]	313	struct im_connection *ic = data;
	314	struct jabber_data *jd = ic->proto_data;
[5997488]	315	char *s;
	316
	317	s = xt_find_attr( node, "xmlns" );
[47d3ac4]	318	if( !s \|\| strcmp( s, XMLNS_SASL ) != 0 )
[5997488]	319	{
[84b045d]	320	imcb_log( ic, "Stream error while authenticating" );
[c2fb3809]	321	imc_logout( ic, FALSE );
[5997488]	322	return XT_ABORT;
	323	}
	324
	325	if( strcmp( node->name, "success" ) == 0 )
	326	{
[84b045d]	327	imcb_log( ic, "Authentication finished" );
[5997488]	328	jd->flags \|= JFLAG_AUTHENTICATED \| JFLAG_STREAM_RESTART;
	329	}
	330	else if( strcmp( node->name, "failure" ) == 0 )
	331	{
[84b045d]	332	imcb_error( ic, "Authentication failure" );
[c2fb3809]	333	imc_logout( ic, FALSE );
[5997488]	334	return XT_ABORT;
	335	}
	336
	337	return XT_HANDLED;
	338	}
[8d74291]	339
	340	/* This one is needed to judge if we'll do authentication using IQ or SASL.
	341	It's done by checking if the <stream:stream> from the server has a
	342	version attribute. I don't know if this is the right way though... */
[0da65d5]	343	gboolean sasl_supported( struct im_connection *ic )
[8d74291]	344	{
[0da65d5]	345	struct jabber_data *jd = ic->proto_data;
[8d74291]	346
[ef5c185]	347	return ( jd->xt && jd->xt->root && xt_find_attr( jd->xt->root, "version" ) ) != 0;
[8d74291]	348	}

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