1/*
2 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19FILE_LICENCE ( GPL2_OR_LATER );
20
21#include <stddef.h>
22#include <stdlib.h>
23#include <string.h>
24#include <errno.h>
25#include <assert.h>
26#include <gpxe/crypto.h>
27#include <gpxe/chap.h>
28
29/** @file
30 *
31 * CHAP protocol
32 *
33 */
34
35/**
36 * Initialise CHAP challenge/response
37 *
38 * @v chap		CHAP challenge/response
39 * @v digest		Digest algorithm to use
40 * @ret rc		Return status code
41 *
42 * Initialises a CHAP challenge/response structure.  This routine
43 * allocates memory, and so may fail.  The allocated memory must
44 * eventually be freed by a call to chap_finish().
45 */
46int chap_init ( struct chap_response *chap,
47		struct digest_algorithm *digest ) {
48	size_t state_len;
49	void *state;
50
51	assert ( chap->digest == NULL );
52	assert ( chap->digest_context == NULL );
53	assert ( chap->response == NULL );
54
55	DBG ( "CHAP %p initialising with %s digest\n", chap, digest->name );
56
57	state_len = ( digest->ctxsize + digest->digestsize );
58	state = malloc ( state_len );
59	if ( ! state ) {
60		DBG ( "CHAP %p could not allocate %zd bytes for state\n",
61		      chap, state_len );
62		return -ENOMEM;
63	}
64
65	chap->digest = digest;
66	chap->digest_context = state;
67	chap->response = ( state + digest->ctxsize );
68	chap->response_len = digest->digestsize;
69	digest_init ( chap->digest, chap->digest_context );
70	return 0;
71}
72
73/**
74 * Add data to the CHAP challenge
75 *
76 * @v chap		CHAP response
77 * @v data		Data to add
78 * @v len		Length of data to add
79 */
80void chap_update ( struct chap_response *chap, const void *data,
81		   size_t len ) {
82	assert ( chap->digest != NULL );
83	assert ( chap->digest_context != NULL );
84
85	if ( ! chap->digest )
86		return;
87
88	digest_update ( chap->digest, chap->digest_context, data, len );
89}
90
91/**
92 * Respond to the CHAP challenge
93 *
94 * @v chap		CHAP response
95 *
96 * Calculates the final CHAP response value, and places it in @c
97 * chap->response, with a length of @c chap->response_len.
98 */
99void chap_respond ( struct chap_response *chap ) {
100	assert ( chap->digest != NULL );
101	assert ( chap->digest_context != NULL );
102	assert ( chap->response != NULL );
103
104	DBG ( "CHAP %p responding to challenge\n", chap );
105
106	if ( ! chap->digest )
107		return;
108
109	digest_final ( chap->digest, chap->digest_context, chap->response );
110}
111
112/**
113 * Free resources used by a CHAP response
114 *
115 * @v chap		CHAP response
116 */
117void chap_finish ( struct chap_response *chap ) {
118	void *state = chap->digest_context;
119
120	DBG ( "CHAP %p finished\n", chap );
121
122	free ( state );
123	memset ( chap, 0, sizeof ( *chap ) );
124}
125