132 lines
3.7 KiB
C
132 lines
3.7 KiB
C
/*
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* Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*
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* You can also choose to distribute this program under the terms of
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* the Unmodified Binary Distribution Licence (as given in the file
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* COPYING.UBDL), provided that you have satisfied its requirements.
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*
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* Alternatively, you may distribute this code in source or binary
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* form, with or without modification, provided that the following
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* conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the above disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the above
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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/** @file
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*
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* RBG mechanism
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*
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* This mechanism is designed to comply with ANS X9.82 Part 4 (April
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* 2011 Draft) Section 10. This standard is unfortunately not freely
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* available.
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*
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* The chosen RBG design is that of a DRBG with a live entropy source
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* with no conditioning function. Only a single security strength is
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* supported. No seedfile is used since there may be no non-volatile
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* storage available. The system UUID is used as the personalisation
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* string.
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*/
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#include <stdint.h>
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#include <string.h>
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#include <ipxe/init.h>
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#include <ipxe/settings.h>
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#include <ipxe/uuid.h>
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#include <ipxe/crypto.h>
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#include <ipxe/drbg.h>
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#include <ipxe/rbg.h>
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/** The RBG */
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struct random_bit_generator rbg;
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/**
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* Start up RBG
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*
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* @ret rc Return status code
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*
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* This is the RBG_Startup function defined in ANS X9.82 Part 4 (April
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* 2011 Draft) Section 9.1.2.2.
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*/
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static int rbg_startup ( void ) {
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union uuid uuid;
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int len;
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int rc;
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/* Try to obtain system UUID for use as personalisation
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* string, in accordance with ANS X9.82 Part 3-2007 Section
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* 8.5.2. If no UUID is available, proceed without a
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* personalisation string.
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*/
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if ( ( len = fetch_uuid_setting ( NULL, &uuid_setting, &uuid ) ) < 0 ) {
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rc = len;
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DBGC ( &rbg, "RBG could not fetch personalisation string: "
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"%s\n", strerror ( rc ) );
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len = 0;
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}
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/* Instantiate DRBG */
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if ( ( rc = drbg_instantiate ( &rbg.state, &uuid, len ) ) != 0 ) {
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DBGC ( &rbg, "RBG could not instantiate DRBG: %s\n",
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strerror ( rc ) );
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return rc;
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}
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return 0;
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}
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/**
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* Shut down RBG
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*
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*/
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static void rbg_shutdown ( void ) {
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/* Uninstantiate DRBG */
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drbg_uninstantiate ( &rbg.state );
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}
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/** RBG startup function */
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static void rbg_startup_fn ( void ) {
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/* Start up RBG. There is no way to report an error at this
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* stage, but a failed startup will result in an invalid DRBG
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* that refuses to generate bits.
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*/
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rbg_startup();
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}
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/** RBG shutdown function */
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static void rbg_shutdown_fn ( int booting __unused ) {
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/* Shut down RBG */
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rbg_shutdown();
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}
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/** RBG startup table entry */
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struct startup_fn startup_rbg __startup_fn ( STARTUP_NORMAL ) = {
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.startup = rbg_startup_fn,
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.shutdown = rbg_shutdown_fn,
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};
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