FreeBSD-5.3/sys/geom/geom_aes.c
/*-
* Copyright (c) 2002 Poul-Henning Kamp
* Copyright (c) 2002 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project by Poul-Henning Kamp
* and NAI Labs, the Security Research Division of Network Associates, Inc.
* under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
* DARPA CHATS research program.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The names of the authors may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* This method provides AES encryption with a compiled in key (default
* all zeroes).
*
* XXX: This could probably save a lot of code by pretending to be a slicer.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/geom/geom_aes.c,v 1.26 2004/08/08 07:57:51 phk Exp $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/bio.h>
#include <sys/malloc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/libkern.h>
#include <sys/endian.h>
#include <sys/md5.h>
#include <sys/errno.h>
#include <geom/geom.h>
#include <crypto/rijndael/rijndael.h>
#include <crypto/rijndael/rijndael.h>
#define AES_CLASS_NAME "AES"
#define MASTER_KEY_LENGTH (1024/8)
static const u_char *aes_magic = "<<FreeBSD-GEOM-AES>>";
static const u_char *aes_magic_random = "<<FreeBSD-GEOM-AES-RANDOM>>";
static const u_char *aes_magic_test = "<<FreeBSD-GEOM-AES-TEST>>";
struct g_aes_softc {
enum {
KEY_ZERO,
KEY_RANDOM,
KEY_TEST
} keying;
u_int sectorsize;
off_t mediasize;
cipherInstance ci;
u_char master_key[MASTER_KEY_LENGTH];
};
/*
* Generate a sectorkey from the masterkey and the offset position.
*
* For KEY_ZERO we just return a key of all zeros.
*
* We feed the sector byte offset, 16 bytes of the master-key and
* the sector byte offset once more to MD5.
* The sector byte offset is converted to little-endian format first
* to support multi-architecture operation.
* We use 16 bytes from the master-key starting at the logical sector
* number modulus he length of the master-key. If need be we wrap
* around to the start of the master-key.
*/
static void
g_aes_makekey(struct g_aes_softc *sc, off_t off, keyInstance *ki, int dir)
{
MD5_CTX cx;
u_int64_t u64;
u_int u, u1;
u_char *p, buf[16];
if (sc->keying == KEY_ZERO) {
rijndael_makeKey(ki, dir, 128, sc->master_key);
return;
}
MD5Init(&cx);
u64 = htole64(off);
MD5Update(&cx, (u_char *)&u64, sizeof(u64));
u = off / sc->sectorsize;
u %= sizeof sc->master_key;
p = sc->master_key + u;
if (u + 16 <= sizeof(sc->master_key)) {
MD5Update(&cx, p, 16);
} else {
u1 = sizeof sc->master_key - u;
MD5Update(&cx, p, u1);
MD5Update(&cx, sc->master_key, 16 - u1);
u1 = 0; /* destroy evidence */
}
u = 0; /* destroy evidence */
MD5Update(&cx, (u_char *)&u64, sizeof(u64));
u64 = 0; /* destroy evidence */
MD5Final(buf, &cx);
bzero(&cx, sizeof cx); /* destroy evidence */
rijndael_makeKey(ki, dir, 128, buf);
bzero(buf, sizeof buf); /* destroy evidence */
}
static void
g_aes_read_done(struct bio *bp)
{
struct g_geom *gp;
struct g_aes_softc *sc;
u_char *p, *b, *e, *sb;
keyInstance dkey;
off_t o;
gp = bp->bio_from->geom;
sc = gp->softc;
sb = g_malloc(sc->sectorsize, M_WAITOK);
b = bp->bio_data;
e = bp->bio_data;
e += bp->bio_length;
o = bp->bio_offset - sc->sectorsize;
for (p = b; p < e; p += sc->sectorsize) {
g_aes_makekey(sc, o, &dkey, DIR_DECRYPT);
rijndael_blockDecrypt(&sc->ci, &dkey, p, sc->sectorsize * 8, sb);
bcopy(sb, p, sc->sectorsize);
o += sc->sectorsize;
}
bzero(&dkey, sizeof dkey); /* destroy evidence */
bzero(sb, sc->sectorsize); /* destroy evidence */
g_free(sb);
g_std_done(bp);
}
static void
g_aes_write_done(struct bio *bp)
{
bzero(bp->bio_data, bp->bio_length); /* destroy evidence */
g_free(bp->bio_data);
g_std_done(bp);
}
static void
g_aes_start(struct bio *bp)
{
struct g_geom *gp;
struct g_consumer *cp;
struct g_aes_softc *sc;
struct bio *bp2;
u_char *p1, *p2, *b, *e;
keyInstance ekey;
off_t o;
gp = bp->bio_to->geom;
cp = LIST_FIRST(&gp->consumer);
sc = gp->softc;
switch (bp->bio_cmd) {
case BIO_READ:
bp2 = g_clone_bio(bp);
if (bp2 == NULL) {
g_io_deliver(bp, ENOMEM);
return;
}
bp2->bio_done = g_aes_read_done;
bp2->bio_offset += sc->sectorsize;
g_io_request(bp2, cp);
break;
case BIO_WRITE:
bp2 = g_clone_bio(bp);
if (bp2 == NULL) {
g_io_deliver(bp, ENOMEM);
return;
}
bp2->bio_done = g_aes_write_done;
bp2->bio_offset += sc->sectorsize;
bp2->bio_data = g_malloc(bp->bio_length, M_WAITOK);
b = bp->bio_data;
e = bp->bio_data;
e += bp->bio_length;
p2 = bp2->bio_data;
o = bp->bio_offset;
for (p1 = b; p1 < e; p1 += sc->sectorsize) {
g_aes_makekey(sc, o, &ekey, DIR_ENCRYPT);
rijndael_blockEncrypt(&sc->ci, &ekey,
p1, sc->sectorsize * 8, p2);
p2 += sc->sectorsize;
o += sc->sectorsize;
}
bzero(&ekey, sizeof ekey); /* destroy evidence */
g_io_request(bp2, cp);
break;
case BIO_GETATTR:
bp2 = g_clone_bio(bp);
if (bp2 == NULL) {
g_io_deliver(bp, ENOMEM);
return;
}
bp2->bio_done = g_std_done;
bp2->bio_offset += sc->sectorsize;
g_io_request(bp2, cp);
break;
default:
g_io_deliver(bp, EOPNOTSUPP);
return;
}
return;
}
static void
g_aes_orphan(struct g_consumer *cp)
{
struct g_geom *gp;
struct g_aes_softc *sc;
g_trace(G_T_TOPOLOGY, "g_aes_orphan(%p/%s)", cp, cp->provider->name);
g_topology_assert();
KASSERT(cp->provider->error != 0,
("g_aes_orphan with error == 0"));
gp = cp->geom;
sc = gp->softc;
g_wither_geom(gp, cp->provider->error);
bzero(sc, sizeof(struct g_aes_softc)); /* destroy evidence */
g_free(sc);
return;
}
static int
g_aes_access(struct g_provider *pp, int dr, int dw, int de)
{
struct g_geom *gp;
struct g_consumer *cp;
gp = pp->geom;
cp = LIST_FIRST(&gp->consumer);
/* On first open, grab an extra "exclusive" bit */
if (cp->acr == 0 && cp->acw == 0 && cp->ace == 0)
de++;
/* ... and let go of it on last close */
if ((cp->acr + dr) == 0 && (cp->acw + dw) == 0 && (cp->ace + de) == 1)
de--;
return (g_access(cp, dr, dw, de));
}
static struct g_geom *
g_aes_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
{
struct g_geom *gp;
struct g_consumer *cp;
struct g_aes_softc *sc;
int error;
u_int sectorsize;
off_t mediasize;
u_char *buf;
g_trace(G_T_TOPOLOGY, "aes_taste(%s,%s)", mp->name, pp->name);
g_topology_assert();
gp = g_new_geomf(mp, "%s.aes", pp->name);
cp = g_new_consumer(gp);
g_attach(cp, pp);
error = g_access(cp, 1, 0, 0);
if (error) {
g_detach(cp);
g_destroy_consumer(cp);
g_destroy_geom(gp);
return (NULL);
}
buf = NULL;
g_topology_unlock();
do {
if (gp->rank != 2)
break;
sectorsize = cp->provider->sectorsize;
mediasize = cp->provider->mediasize;
buf = g_read_data(cp, 0, sectorsize, &error);
if (buf == NULL || error != 0) {
break;
}
sc = g_malloc(sizeof(struct g_aes_softc), M_WAITOK | M_ZERO);
if (!memcmp(buf, aes_magic, strlen(aes_magic))) {
sc->keying = KEY_ZERO;
} else if (!memcmp(buf, aes_magic_random,
strlen(aes_magic_random))) {
sc->keying = KEY_RANDOM;
} else if (!memcmp(buf, aes_magic_test,
strlen(aes_magic_test))) {
sc->keying = KEY_TEST;
} else {
g_free(sc);
break;
}
g_free(buf);
gp->softc = sc;
sc->sectorsize = sectorsize;
sc->mediasize = mediasize - sectorsize;
rijndael_cipherInit(&sc->ci, MODE_CBC, NULL);
if (sc->keying == KEY_TEST) {
int i;
u_char *p;
p = sc->master_key;
for (i = 0; i < (int)sizeof sc->master_key; i ++)
*p++ = i;
}
if (sc->keying == KEY_RANDOM) {
int i;
u_int32_t u;
u_char *p;
p = sc->master_key;
for (i = 0; i < (int)sizeof sc->master_key; i += sizeof u) {
u = arc4random();
*p++ = u;
*p++ = u >> 8;
*p++ = u >> 16;
*p++ = u >> 24;
}
}
g_topology_lock();
pp = g_new_providerf(gp, gp->name);
pp->mediasize = mediasize - sectorsize;
pp->sectorsize = sectorsize;
g_error_provider(pp, 0);
g_topology_unlock();
} while(0);
g_topology_lock();
if (buf)
g_free(buf);
g_access(cp, -1, 0, 0);
if (gp->softc != NULL)
return (gp);
g_detach(cp);
g_destroy_consumer(cp);
g_destroy_geom(gp);
return (NULL);
}
static struct g_class g_aes_class = {
.name = AES_CLASS_NAME,
.version = G_VERSION,
.taste = g_aes_taste,
.start = g_aes_start,
.orphan = g_aes_orphan,
.spoiled = g_std_spoiled,
.access = g_aes_access,
};
DECLARE_GEOM_CLASS(g_aes_class, g_aes);