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.

2 files changed, 275 insertions, 0 deletions

diff --git a/sys/conf/files b/sys/conf/files
index a2011da..7a67183 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -716,6 +716,7 @@ fs/umapfs/umap_vnops.c	optional umapfs
 fs/unionfs/union_subr.c	optional unionfs
 fs/unionfs/union_vfsops.c	optional unionfs
 fs/unionfs/union_vnops.c	optional unionfs
+geom/geom_aes.c	optional geom
 geom/geom_bsd.c	optional geom
 geom/geom_dev.c	optional geom
 geom/geom_disk.c	optional geom
diff --git a/sys/geom/geom_aes.c b/sys/geom/geom_aes.c
new file mode 100644
index 0000000..6ac7bb6
--- /dev/null
+++ b/sys/geom/geom_aes.c
@@ -0,0 +1,274 @@
+/*-
+ * 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.
+ *
+ * $FreeBSD$
+ *
+ * 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/param.h>
+#ifndef _KERNEL
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <err.h>
+#else
+#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>
+#endif
+#include <sys/errno.h>
+#include <geom/geom.h>
+
+#include <crypto/rijndael/rijndael.h>
+
+#include <crypto/rijndael/rijndael.h>
+
+#define AES_CLASS_NAME "AES"
+
+static u_char *aes_magic = "<<FreeBSD-GEOM-AES>>";
+
+static u_char aes_key[128 / 8] = {
+	0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0,  0, 0, 0, 0
+};
+
+struct g_aes_softc {
+	u_int	sectorsize;
+	off_t	mediasize;
+	keyInstance ekey;
+	keyInstance dkey;
+	cipherInstance ci;
+};
+
+static void
+g_aes_read_done(struct bio *bp)
+{
+	struct g_geom *gp;
+	struct g_aes_softc *sc;
+	u_char *p, *b, *e, *sb;
+
+	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;
+	for (p = b; p < e; p += sc->sectorsize) {
+		rijndael_blockDecrypt(&sc->ci, &sc->dkey, p, sc->sectorsize * 8, sb);
+		bcopy(sb, p, sc->sectorsize);
+	}
+	g_std_done(bp);
+}
+
+static void
+g_aes_write_done(struct bio *bp)
+{
+
+	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;
+
+	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);
+		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);
+		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;
+		for (p1 = b; p1 < e; p1 += sc->sectorsize) {
+			rijndael_blockEncrypt(&sc->ci, &sc->ekey,
+			    p1, sc->sectorsize * 8, p2);
+			p2 += sc->sectorsize;
+		}
+		g_io_request(bp2, cp);
+		break;
+	case BIO_GETATTR:
+	case BIO_SETATTR:
+		if (g_haveattr_off_t(bp, "GEOM::mediasize", sc->mediasize))
+			return;
+		if (g_haveattr_int(bp, "GEOM::sectorsize", sc->sectorsize))
+			return;
+		bp2 = g_clone_bio(bp);
+		bp2->bio_done = g_std_done;
+		bp2->bio_offset += sc->sectorsize;
+		g_io_request(bp2, cp);
+		break;
+	default:
+		bp->bio_error = EOPNOTSUPP;
+		g_io_deliver(bp);
+		return;
+	}
+	return;
+}
+
+static void
+g_aes_orphan(struct g_consumer *cp)
+{
+	struct g_geom *gp;
+	struct g_provider *pp;
+	int error;
+
+	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;
+	gp->flags |= G_GEOM_WITHER;
+	error = cp->provider->error;
+	LIST_FOREACH(pp, &gp->provider, provider)
+		g_orphan_provider(pp, error);
+	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_rel(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);
+	gp->start = g_aes_start;
+	gp->orphan = g_aes_orphan;
+	gp->spoiled = g_std_spoiled;
+	cp = g_new_consumer(gp);
+	g_attach(cp, pp);
+	error = g_access_rel(cp, 1, 0, 0);
+	if (error) {
+		g_dettach(cp);
+		g_destroy_consumer(cp);
+		g_destroy_geom(gp);
+		return (NULL);
+	}
+	buf = NULL;
+	while (1) {
+		if (gp->rank != 2)
+			break;
+		error = g_getattr("GEOM::sectorsize", cp, &sectorsize);
+		if (error)
+			break;
+		error = g_getattr("GEOM::mediasize", cp, &mediasize);
+		if (error)
+			break;
+		buf = g_read_data(cp, 0, sectorsize, &error);
+		if (buf == NULL || error != 0) {
+			break;
+		}
+		if (memcmp(buf, aes_magic, strlen(aes_magic)))
+			break;
+		sc = g_malloc(sizeof(struct g_aes_softc), M_WAITOK | M_ZERO);
+		gp->softc = sc;
+		gp->access = g_aes_access;
+		sc->sectorsize = sectorsize;
+		sc->mediasize = mediasize - sectorsize;
+		rijndael_cipherInit(&sc->ci, MODE_CBC, NULL);
+		rijndael_makeKey(&sc->ekey, DIR_ENCRYPT, 128, aes_key);
+		rijndael_makeKey(&sc->dkey, DIR_DECRYPT, 128, aes_key);
+		pp = g_new_providerf(gp, gp->name);
+		pp->mediasize = mediasize - sectorsize;
+		g_error_provider(pp, 0);
+		break;
+	}
+	if (buf)
+		g_free(buf);
+	g_access_rel(cp, -1, 0, 0);
+	if (gp->softc != NULL) 
+		return (gp);
+	g_dettach(cp);
+	g_destroy_consumer(cp);
+	g_destroy_geom(gp);
+	return (NULL);
+}
+
+static struct g_class g_aes_class	= {
+	AES_CLASS_NAME,
+	g_aes_taste,
+	NULL,
+	G_CLASS_INITSTUFF
+};
+
+DECLARE_GEOM_CLASS(g_aes_class, g_aes);