Files
ipxe/src/crypto/ecdhe.c
Michael Brown adcaaf9b93 [build] Mark known reviewed files as permitted for UEFI Secure Boot
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Signed-off-by: Michael Brown <mcb30@ipxe.org>
2026-01-14 16:10:29 +00:00

76 lines
2.3 KiB
C

/*
* Copyright (C) 2025 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., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );
/** @file
*
* Elliptic Curve Ephemeral Diffie-Hellman (ECDHE) key exchange
*
*/
#include <string.h>
#include <errno.h>
#include <ipxe/ecdhe.h>
/**
* Calculate ECDHE key
*
* @v curve Elliptic curve
* @v partner Partner public curve point
* @v private Private key
* @v public Public curve point to fill in (may overlap partner key)
* @v shared Shared secret curve point to fill in
* @ret rc Return status code
*/
int ecdhe_key ( struct elliptic_curve *curve, const void *partner,
const void *private, void *public, void *shared ) {
int rc;
/* Construct shared key */
if ( ( rc = elliptic_multiply ( curve, partner, private,
shared ) ) != 0 ) {
DBGC ( curve, "CURVE %s could not generate shared key: %s\n",
curve->name, strerror ( rc ) );
return rc;
}
/* Construct public key */
if ( ( rc = elliptic_multiply ( curve, curve->base, private,
public ) ) != 0 ) {
DBGC ( curve, "CURVE %s could not generate public key: %s\n",
curve->name, strerror ( rc ) );
return rc;
}
/* Check that partner and shared keys are not the point at infinity */
if ( elliptic_is_infinity ( curve, shared ) ) {
DBGC ( curve, "CURVE %s constructed point at infinity\n",
curve->name );
return -EPERM;
}
return 0;
}