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