/*
* Copyright (c) 2012 Apple Computer, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <libkern/crypto/crypto_internal.h>
#include <libkern/libkern.h>
#include <libkern/crypto/aesxts.h>
#include <corecrypto/ccmode.h>
#include <corecrypto/ccpad.h>
#include <kern/debug.h>
/*
* These are the interfaces required for XTS-AES support
*/
uint32_t
xts_start(uint32_t cipher __unused, // ignored - we're doing this for xts-aes only
const uint8_t *IV __unused, // ignored
const uint8_t *key1, int keylen,
const uint8_t *key2, int tweaklen __unused, // both keys are the same size for xts
uint32_t num_rounds __unused, // ignored
uint32_t options __unused, // ignored
symmetric_xts *xts)
{
const struct ccmode_xts *enc, *dec;
if (!g_crypto_funcs) {
panic("%s: corecrypto not registered!", __FUNCTION__);
}
enc = g_crypto_funcs->ccaes_xts_encrypt;
dec = g_crypto_funcs->ccaes_xts_decrypt;
if (!enc || !dec) {
panic("%s: xts mode not registered? enc=%p, dec=%p", __FUNCTION__, enc, dec);
}
/* Make sure the context size for the mode fits in the one we have */
if ((enc->size > sizeof(xts->enc)) || (dec->size > sizeof(xts->dec))) {
panic("%s: inconsistent size for AES-XTS context", __FUNCTION__);
}
int rc = enc->init(enc, xts->enc, keylen, key1, key2);
rc |= dec->init(dec, xts->dec, keylen, key1, key2);
return rc;
}
int
xts_encrypt(const uint8_t *pt, unsigned long ptlen,
uint8_t *ct,
const uint8_t *iv, // this can be considered the sector IV for this use
symmetric_xts *xts)
{
const struct ccmode_xts *xtsenc = g_crypto_funcs->ccaes_xts_encrypt;
ccxts_tweak_decl(xtsenc->tweak_size, tweak);
if (ptlen % 16) {
panic("xts encrypt not a multiple of block size");
}
int rc = xtsenc->set_tweak(xts->enc, tweak, iv);
if (rc) {
return rc;
}
xtsenc->xts(xts->enc, tweak, ptlen / 16, pt, ct);
return 0;
}
int
xts_decrypt(const uint8_t *ct, unsigned long ptlen,
uint8_t *pt,
const uint8_t *iv, // this can be considered the sector IV for this use
symmetric_xts *xts)
{
const struct ccmode_xts *xtsdec = g_crypto_funcs->ccaes_xts_decrypt;
ccxts_tweak_decl(xtsdec->tweak_size, tweak);
if (ptlen % 16) {
panic("xts decrypt not a multiple of block size");
}
int rc = xtsdec->set_tweak(xts->dec, tweak, iv);
if (rc) {
return rc;
}
xtsdec->xts(xts->dec, tweak, ptlen / 16, ct, pt);
return 0;
}
void
xts_done(symmetric_xts *xts __unused)
{
cc_clear(sizeof(xts->enc), xts->enc);
cc_clear(sizeof(xts->dec), xts->dec);
}