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/*
* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <gpxe/crypto.h>
#include <gpxe/chap.h>
/** @file
*
* CHAP protocol
*
*/
/**
* Initialise CHAP challenge/response
*
* @v chap CHAP challenge/response
* @v digest Digest algorithm to use
* @ret rc Return status code
*
* Initialises a CHAP challenge/response structure. This routine
* allocates memory, and so may fail. The allocated memory must
* eventually be freed by a call to chap_finish().
*/
int chap_init ( struct chap_response *chap,
struct digest_algorithm *digest ) {
size_t state_len;
void *state;
assert ( chap->digest == NULL );
assert ( chap->digest_context == NULL );
assert ( chap->response == NULL );
DBG ( "CHAP %p initialising with %s digest\n", chap, digest->name );
state_len = ( digest->ctxsize + digest->digestsize );
state = malloc ( state_len );
if ( ! state ) {
DBG ( "CHAP %p could not allocate %zd bytes for state\n",
chap, state_len );
return -ENOMEM;
}
chap->digest = digest;
chap->digest_context = state;
chap->response = ( state + digest->ctxsize );
chap->response_len = digest->digestsize;
digest_init ( chap->digest, chap->digest_context );
return 0;
}
/**
* Add data to the CHAP challenge
*
* @v chap CHAP response
* @v data Data to add
* @v len Length of data to add
*/
void chap_update ( struct chap_response *chap, const void *data,
size_t len ) {
assert ( chap->digest != NULL );
assert ( chap->digest_context != NULL );
if ( ! chap->digest )
return;
digest_update ( chap->digest, chap->digest_context, data, len );
}
/**
* Respond to the CHAP challenge
*
* @v chap CHAP response
*
* Calculates the final CHAP response value, and places it in @c
* chap->response, with a length of @c chap->response_len.
*/
void chap_respond ( struct chap_response *chap ) {
assert ( chap->digest != NULL );
assert ( chap->digest_context != NULL );
assert ( chap->response != NULL );
DBG ( "CHAP %p responding to challenge\n", chap );
if ( ! chap->digest )
return;
digest_final ( chap->digest, chap->digest_context, chap->response );
}
/**
* Free resources used by a CHAP response
*
* @v chap CHAP response
*/
void chap_finish ( struct chap_response *chap ) {
void *state = chap->digest_context;
DBG ( "CHAP %p finished\n", chap );
free ( state );
memset ( chap, 0, sizeof ( *chap ) );
}
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