mirror of https://github.com/ipxe/ipxe.git
77 lines
2.2 KiB
C
77 lines
2.2 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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FILE_LICENCE ( GPL2_OR_LATER );
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/** @file
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*
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* Random non-zero bytes
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*
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* The RSA algorithm requires the generation of random non-zero bytes,
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* i.e. bytes in the range [0x01,0xff].
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*
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* This algorithm is designed to comply with ANS X9.82 Part 1-2006
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* Section 9.2.1. This standard is not freely available, but most of
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* the text appears to be shared with NIST SP 800-90, which can be
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* downloaded from
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*
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* http://csrc.nist.gov/publications/nistpubs/800-90/SP800-90revised_March2007.pdf
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*
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* Where possible, references are given to both documents. In the
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* case of any disagreement, ANS X9.82 takes priority over NIST SP
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* 800-90. (In particular, note that some algorithms that are
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* Approved by NIST SP 800-90 are not Approved by ANS X9.82.)
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*/
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#include <stddef.h>
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#include <stdint.h>
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#include <ipxe/rbg.h>
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#include <ipxe/random_nz.h>
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/**
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* Get random non-zero bytes
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*
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* @v data Output buffer
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* @v len Length of output buffer
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* @ret rc Return status code
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*
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* This algorithm is designed to be isomorphic to the Simple Discard
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* Method described in ANS X9.82 Part 1-2006 Section 9.2.1 (NIST SP
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* 800-90 Section B.5.1.1).
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*/
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int get_random_nz ( void *data, size_t len ) {
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uint8_t *bytes = data;
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int rc;
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while ( len ) {
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/* Generate random byte */
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if ( ( rc = rbg_generate ( NULL, 0, 0, bytes, 1 ) ) != 0 )
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return rc;
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/* Move to next byte if this byte is acceptable */
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if ( *bytes != 0 ) {
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bytes++;
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len--;
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}
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}
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return 0;
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}
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