3728855a0f
Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts.
363 lines
10 KiB
C
363 lines
10 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2002 Poul-Henning Kamp
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* Copyright (c) 2002 Networks Associates Technology, Inc.
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* All rights reserved.
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*
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* This software was developed for the FreeBSD Project by Poul-Henning Kamp
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* and NAI Labs, the Security Research Division of Network Associates, Inc.
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* under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
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* DARPA CHATS research program.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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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 following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/* This source file contains the functions responsible for the crypto, keying
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* and mapping operations on the I/O requests.
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*
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*/
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#include <sys/param.h>
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#include <sys/bio.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/queue.h>
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#include <sys/malloc.h>
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#include <sys/libkern.h>
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#include <sys/endian.h>
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#include <sys/md5.h>
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#include <crypto/rijndael/rijndael-api-fst.h>
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#include <crypto/sha2/sha512.h>
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#include <geom/geom.h>
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#include <geom/bde/g_bde.h>
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/*
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* XXX: Debugging DO NOT ENABLE
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*/
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#undef MD5_KEY
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/*
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* Derive kkey from mkey + sector offset.
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*
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* Security objective: Derive a potentially very large number of distinct skeys
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* from the comparatively small key material in our mkey, in such a way that
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* if one, more or even many of the kkeys are compromised, this does not
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* significantly help an attack on other kkeys and in particular does not
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* weaken or compromise the mkey.
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*
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* First we MD5 hash the sectornumber with the salt from the lock sector.
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* The salt prevents the precalculation and statistical analysis of the MD5
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* output which would be possible if we only gave it the sectornumber.
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*
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* The MD5 hash is used to pick out 16 bytes from the masterkey, which
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* are then hashed with MD5 together with the sector number.
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*
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* The resulting MD5 hash is the kkey.
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*/
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static void
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g_bde_kkey(struct g_bde_softc *sc, keyInstance *ki, int dir, off_t sector)
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{
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u_int t;
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MD5_CTX ct;
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u_char buf[16];
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u_char buf2[8];
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/* We have to be architecture neutral */
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le64enc(buf2, sector);
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MD5Init(&ct);
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MD5Update(&ct, sc->key.salt, 8);
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MD5Update(&ct, buf2, sizeof buf2);
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MD5Update(&ct, sc->key.salt + 8, 8);
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MD5Final(buf, &ct);
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MD5Init(&ct);
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for (t = 0; t < 16; t++) {
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MD5Update(&ct, &sc->key.mkey[buf[t]], 1);
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if (t == 8)
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MD5Update(&ct, buf2, sizeof buf2);
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}
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bzero(buf2, sizeof buf2);
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MD5Final(buf, &ct);
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bzero(&ct, sizeof ct);
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AES_makekey(ki, dir, G_BDE_KKEYBITS, buf);
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bzero(buf, sizeof buf);
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}
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/*
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* Encryption work for read operation.
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*
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* Security objective: Find the kkey, find the skey, decrypt the sector data.
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*/
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void
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g_bde_crypt_read(struct g_bde_work *wp)
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{
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struct g_bde_softc *sc;
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u_char *d;
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u_int n;
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off_t o;
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u_char skey[G_BDE_SKEYLEN];
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keyInstance ki;
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cipherInstance ci;
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AES_init(&ci);
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sc = wp->softc;
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o = 0;
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for (n = 0; o < wp->length; n++, o += sc->sectorsize) {
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d = (u_char *)wp->ksp->data + wp->ko + n * G_BDE_SKEYLEN;
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g_bde_kkey(sc, &ki, DIR_DECRYPT, wp->offset + o);
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AES_decrypt(&ci, &ki, d, skey, sizeof skey);
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d = (u_char *)wp->data + o;
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AES_makekey(&ki, DIR_DECRYPT, G_BDE_SKEYBITS, skey);
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AES_decrypt(&ci, &ki, d, d, sc->sectorsize);
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}
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bzero(skey, sizeof skey);
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bzero(&ci, sizeof ci);
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bzero(&ki, sizeof ki);
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}
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/*
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* Encryption work for write operation.
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*
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* Security objective: Create random skey, encrypt sector data,
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* encrypt skey with the kkey.
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*/
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void
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g_bde_crypt_write(struct g_bde_work *wp)
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{
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u_char *s, *d;
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struct g_bde_softc *sc;
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u_int n;
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off_t o;
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u_char skey[G_BDE_SKEYLEN];
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keyInstance ki;
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cipherInstance ci;
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sc = wp->softc;
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AES_init(&ci);
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o = 0;
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for (n = 0; o < wp->length; n++, o += sc->sectorsize) {
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s = (u_char *)wp->data + o;
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d = (u_char *)wp->sp->data + o;
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arc4rand(skey, sizeof skey, 0);
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AES_makekey(&ki, DIR_ENCRYPT, G_BDE_SKEYBITS, skey);
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AES_encrypt(&ci, &ki, s, d, sc->sectorsize);
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d = (u_char *)wp->ksp->data + wp->ko + n * G_BDE_SKEYLEN;
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g_bde_kkey(sc, &ki, DIR_ENCRYPT, wp->offset + o);
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AES_encrypt(&ci, &ki, skey, d, sizeof skey);
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bzero(skey, sizeof skey);
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}
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bzero(skey, sizeof skey);
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bzero(&ci, sizeof ci);
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bzero(&ki, sizeof ki);
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}
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/*
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* Encryption work for delete operation.
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*
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* Security objective: Write random data to the sectors.
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*
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* XXX: At a hit in performance we would trash the encrypted skey as well.
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* XXX: This would add frustration to the cleaning lady attack by making
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* XXX: deletes look like writes.
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*/
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void
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g_bde_crypt_delete(struct g_bde_work *wp)
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{
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struct g_bde_softc *sc;
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u_char *d;
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off_t o;
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u_char skey[G_BDE_SKEYLEN];
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keyInstance ki;
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cipherInstance ci;
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sc = wp->softc;
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d = wp->sp->data;
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AES_init(&ci);
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/*
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* Do not unroll this loop!
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* Our zone may be significantly wider than the amount of random
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* bytes arc4rand likes to give in one reseeding, whereas our
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* sectorsize is far more likely to be in the same range.
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*/
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for (o = 0; o < wp->length; o += sc->sectorsize) {
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arc4rand(d, sc->sectorsize, 0);
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arc4rand(skey, sizeof skey, 0);
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AES_makekey(&ki, DIR_ENCRYPT, G_BDE_SKEYBITS, skey);
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AES_encrypt(&ci, &ki, d, d, sc->sectorsize);
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d += sc->sectorsize;
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}
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/*
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* Having written a long random sequence to disk here, we want to
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* force a reseed, to avoid weakening the next time we use random
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* data for something important.
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*/
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arc4rand(&o, sizeof o, 1);
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}
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/*
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* Calculate the total payload size of the encrypted device.
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*
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* Security objectives: none.
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*
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* This function needs to agree with g_bde_map_sector() about things.
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*/
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uint64_t
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g_bde_max_sector(struct g_bde_key *kp)
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{
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uint64_t maxsect;
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maxsect = kp->media_width;
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maxsect /= kp->zone_width;
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maxsect *= kp->zone_cont;
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return (maxsect);
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}
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/*
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* Convert an unencrypted side offset to offsets on the encrypted side.
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*
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* Security objective: Make it harder to identify what sectors contain what
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* on a "cold" disk image.
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*
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* We do this by adding the "keyoffset" from the lock to the physical sector
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* number modulus the available number of sectors. Since all physical sectors
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* presumably look the same cold, this will do.
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*
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* As part of the mapping we have to skip the lock sectors which we know
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* the physical address off. We also truncate the work packet, respecting
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* zone boundaries and lock sectors, so that we end up with a sequence of
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* sectors which are physically contiguous.
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*
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* Shuffling things further is an option, but the incremental frustration is
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* not currently deemed worth the run-time performance hit resulting from the
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* increased number of disk arm movements it would incur.
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*
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* This function offers nothing but a trivial diversion for an attacker able
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* to do "the cleaning lady attack" in its current static mapping form.
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*/
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void
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g_bde_map_sector(struct g_bde_work *wp)
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{
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u_int zone, zoff, u, len;
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uint64_t ko;
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struct g_bde_softc *sc;
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struct g_bde_key *kp;
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sc = wp->softc;
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kp = &sc->key;
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/* find which zone and the offset in it */
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zone = wp->offset / kp->zone_cont;
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zoff = wp->offset % kp->zone_cont;
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/* Calculate the offset of the key in the key sector */
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wp->ko = (zoff / kp->sectorsize) * G_BDE_SKEYLEN;
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/* restrict length to that zone */
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len = kp->zone_cont - zoff;
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/* ... and in general */
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if (len > DFLTPHYS)
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len = DFLTPHYS;
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if (len < wp->length)
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wp->length = len;
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/* Find physical sector address */
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wp->so = zone * kp->zone_width + zoff;
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wp->so += kp->keyoffset;
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wp->so %= kp->media_width;
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if (wp->so + wp->length > kp->media_width)
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wp->length = kp->media_width - wp->so;
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wp->so += kp->sector0;
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/* The key sector is the last in this zone. */
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wp->kso = zone * kp->zone_width + kp->zone_cont;
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wp->kso += kp->keyoffset;
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wp->kso %= kp->media_width;
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wp->kso += kp->sector0;
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/* Compensate for lock sectors */
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for (u = 0; u < G_BDE_MAXKEYS; u++) {
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/* Find the start of this lock sector */
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ko = rounddown2(kp->lsector[u], (uint64_t)kp->sectorsize);
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if (wp->kso >= ko)
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wp->kso += kp->sectorsize;
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if (wp->so >= ko) {
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/* lock sector before work packet */
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wp->so += kp->sectorsize;
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} else if ((wp->so + wp->length) > ko) {
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/* lock sector in work packet, truncate */
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wp->length = ko - wp->so;
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}
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}
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#if 0
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printf("off %jd len %jd so %jd ko %jd kso %u\n",
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(intmax_t)wp->offset,
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(intmax_t)wp->length,
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(intmax_t)wp->so,
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(intmax_t)wp->kso,
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wp->ko);
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#endif
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KASSERT(wp->so + wp->length <= kp->sectorN,
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("wp->so (%jd) + wp->length (%jd) > EOM (%jd), offset = %jd",
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(intmax_t)wp->so,
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(intmax_t)wp->length,
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(intmax_t)kp->sectorN,
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(intmax_t)wp->offset));
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KASSERT(wp->kso + kp->sectorsize <= kp->sectorN,
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("wp->kso (%jd) + kp->sectorsize > EOM (%jd), offset = %jd",
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(intmax_t)wp->kso,
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(intmax_t)kp->sectorN,
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(intmax_t)wp->offset));
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KASSERT(wp->so >= kp->sector0,
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("wp->so (%jd) < BOM (%jd), offset = %jd",
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(intmax_t)wp->so,
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(intmax_t)kp->sector0,
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(intmax_t)wp->offset));
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KASSERT(wp->kso >= kp->sector0,
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("wp->kso (%jd) <BOM (%jd), offset = %jd",
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(intmax_t)wp->kso,
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(intmax_t)kp->sector0,
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(intmax_t)wp->offset));
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}
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