Add a proof-of-concept encryption class.
"The only hard problem in cryptography is key-management." All sectors are encrypted with AES in CBC mode using a constant key, currently compiled in and all zero. To activate this module, write the magic header on the partition: echo "<<FreeBSD-GEOM-AES>>" | dd conv=sync of=/dev/md98 The encrypted device will be one sector shorter and have ".aes" appended to its name. Sponsored by: DARPA & NAI Labs.
This commit is contained in:
Poul-Henning Kamp
parent
d4116af4f9
commit
291daf5735
@ -716,6 +716,7 @@ fs/umapfs/umap_vnops.c optional umapfs
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fs/unionfs/union_subr.c optional unionfs
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fs/unionfs/union_vfsops.c optional unionfs
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fs/unionfs/union_vnops.c optional unionfs
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geom/geom_aes.c optional geom
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geom/geom_bsd.c optional geom
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geom/geom_dev.c optional geom
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geom/geom_disk.c optional geom
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274
sys/geom/geom_aes.c
Normal file
274
sys/geom/geom_aes.c
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@ -0,0 +1,274 @@
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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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* 3. The names of the authors may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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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 method provides AES encryption with a compiled in key (default
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* all zeroes).
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*
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* XXX: This could probably save a lot of code by pretending to be a slicer.
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*/
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#include <sys/param.h>
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#ifndef _KERNEL
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <err.h>
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#else
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/conf.h>
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#include <sys/bio.h>
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#include <sys/malloc.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#endif
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#include <sys/errno.h>
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#include <geom/geom.h>
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#include <crypto/rijndael/rijndael.h>
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#include <crypto/rijndael/rijndael.h>
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#define AES_CLASS_NAME "AES"
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static u_char *aes_magic = "<<FreeBSD-GEOM-AES>>";
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static u_char aes_key[128 / 8] = {
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
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};
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struct g_aes_softc {
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u_int sectorsize;
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off_t mediasize;
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keyInstance ekey;
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keyInstance dkey;
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cipherInstance ci;
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};
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static void
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g_aes_read_done(struct bio *bp)
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{
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struct g_geom *gp;
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struct g_aes_softc *sc;
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u_char *p, *b, *e, *sb;
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gp = bp->bio_from->geom;
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sc = gp->softc;
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sb = g_malloc(sc->sectorsize, M_WAITOK);
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b = bp->bio_data;
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e = bp->bio_data;
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e += bp->bio_length;
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for (p = b; p < e; p += sc->sectorsize) {
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rijndael_blockDecrypt(&sc->ci, &sc->dkey, p, sc->sectorsize * 8, sb);
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bcopy(sb, p, sc->sectorsize);
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}
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g_std_done(bp);
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}
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static void
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g_aes_write_done(struct bio *bp)
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{
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g_free(bp->bio_data);
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g_std_done(bp);
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}
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static void
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g_aes_start(struct bio *bp)
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{
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struct g_geom *gp;
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struct g_consumer *cp;
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struct g_aes_softc *sc;
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struct bio *bp2;
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u_char *p1, *p2, *b, *e;
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gp = bp->bio_to->geom;
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cp = LIST_FIRST(&gp->consumer);
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sc = gp->softc;
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switch (bp->bio_cmd) {
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case BIO_READ:
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bp2 = g_clone_bio(bp);
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bp2->bio_done = g_aes_read_done;
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bp2->bio_offset += sc->sectorsize;
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g_io_request(bp2, cp);
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break;
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case BIO_WRITE:
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bp2 = g_clone_bio(bp);
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bp2->bio_done = g_aes_write_done;
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bp2->bio_offset += sc->sectorsize;
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bp2->bio_data = g_malloc(bp->bio_length, M_WAITOK);
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b = bp->bio_data;
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e = bp->bio_data;
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e += bp->bio_length;
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p2 = bp2->bio_data;
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for (p1 = b; p1 < e; p1 += sc->sectorsize) {
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rijndael_blockEncrypt(&sc->ci, &sc->ekey,
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p1, sc->sectorsize * 8, p2);
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p2 += sc->sectorsize;
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}
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g_io_request(bp2, cp);
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break;
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case BIO_GETATTR:
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case BIO_SETATTR:
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if (g_haveattr_off_t(bp, "GEOM::mediasize", sc->mediasize))
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return;
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if (g_haveattr_int(bp, "GEOM::sectorsize", sc->sectorsize))
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return;
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bp2 = g_clone_bio(bp);
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bp2->bio_done = g_std_done;
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bp2->bio_offset += sc->sectorsize;
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g_io_request(bp2, cp);
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break;
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default:
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bp->bio_error = EOPNOTSUPP;
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g_io_deliver(bp);
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return;
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}
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return;
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}
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static void
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g_aes_orphan(struct g_consumer *cp)
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{
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struct g_geom *gp;
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struct g_provider *pp;
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int error;
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g_trace(G_T_TOPOLOGY, "g_aes_orphan(%p/%s)", cp, cp->provider->name);
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g_topology_assert();
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KASSERT(cp->provider->error != 0,
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("g_aes_orphan with error == 0"));
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gp = cp->geom;
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gp->flags |= G_GEOM_WITHER;
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error = cp->provider->error;
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LIST_FOREACH(pp, &gp->provider, provider)
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g_orphan_provider(pp, error);
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return;
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}
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static int
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g_aes_access(struct g_provider *pp, int dr, int dw, int de)
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{
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struct g_geom *gp;
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struct g_consumer *cp;
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gp = pp->geom;
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cp = LIST_FIRST(&gp->consumer);
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/* On first open, grab an extra "exclusive" bit */
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if (cp->acr == 0 && cp->acw == 0 && cp->ace == 0)
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de++;
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/* ... and let go of it on last close */
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if ((cp->acr + dr) == 0 && (cp->acw + dw) == 0 && (cp->ace + de) == 1)
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de--;
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return (g_access_rel(cp, dr, dw, de));
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}
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static struct g_geom *
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g_aes_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
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{
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struct g_geom *gp;
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struct g_consumer *cp;
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struct g_aes_softc *sc;
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int error;
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u_int sectorsize;
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off_t mediasize;
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u_char *buf;
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g_trace(G_T_TOPOLOGY, "aes_taste(%s,%s)", mp->name, pp->name);
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g_topology_assert();
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gp = g_new_geomf(mp, "%s.aes", pp->name);
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gp->start = g_aes_start;
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gp->orphan = g_aes_orphan;
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gp->spoiled = g_std_spoiled;
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cp = g_new_consumer(gp);
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g_attach(cp, pp);
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error = g_access_rel(cp, 1, 0, 0);
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if (error) {
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g_dettach(cp);
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g_destroy_consumer(cp);
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g_destroy_geom(gp);
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return (NULL);
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}
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buf = NULL;
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while (1) {
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if (gp->rank != 2)
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break;
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error = g_getattr("GEOM::sectorsize", cp, §orsize);
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if (error)
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break;
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error = g_getattr("GEOM::mediasize", cp, &mediasize);
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if (error)
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break;
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buf = g_read_data(cp, 0, sectorsize, &error);
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if (buf == NULL || error != 0) {
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break;
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}
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if (memcmp(buf, aes_magic, strlen(aes_magic)))
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break;
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sc = g_malloc(sizeof(struct g_aes_softc), M_WAITOK | M_ZERO);
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gp->softc = sc;
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gp->access = g_aes_access;
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sc->sectorsize = sectorsize;
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sc->mediasize = mediasize - sectorsize;
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rijndael_cipherInit(&sc->ci, MODE_CBC, NULL);
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rijndael_makeKey(&sc->ekey, DIR_ENCRYPT, 128, aes_key);
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rijndael_makeKey(&sc->dkey, DIR_DECRYPT, 128, aes_key);
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pp = g_new_providerf(gp, gp->name);
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pp->mediasize = mediasize - sectorsize;
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g_error_provider(pp, 0);
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break;
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}
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if (buf)
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g_free(buf);
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g_access_rel(cp, -1, 0, 0);
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if (gp->softc != NULL)
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return (gp);
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g_dettach(cp);
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g_destroy_consumer(cp);
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g_destroy_geom(gp);
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return (NULL);
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}
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static struct g_class g_aes_class = {
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AES_CLASS_NAME,
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g_aes_taste,
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NULL,
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G_CLASS_INITSTUFF
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};
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DECLARE_GEOM_CLASS(g_aes_class, g_aes);
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