Add Geom Based Disk Encryption to the tree.

This is an encryption module designed for to secure denial of access
to the contents of "cold disks" with or without destruction activation.

Major features:

   * Based on AES, MD5 and ARC4 algorithms.
   * Four cryptographic barriers:
        1) Pass-phrase encrypts the master key.
        2) Pass-phrase + Lock data locates master key.
        3) 128 bit key derived from 2048 bit master key protects sector key.
        3) 128 bit random single-use sector keys protect data payload.
   * Up to four different changeable pass-phrases.
   * Blackening feature for provable destruction of master key material.
   * Isotropic disk contents offers no information about sector contents.
   * Configurable destination sector range allows steganographic deployment.

This commit adds the kernel part, separate commits will follow for the
userland utility and documentation.

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.

Many thanks to Robert Watson, CBOSS Principal Investigator for making this
possible.

Sponsored by:   DARPA & NAI Labs.

1 files changed, 311 insertions, 0 deletions

diff --git a/sys/geom/bde/g_bde_lock.c b/sys/geom/bde/g_bde_lock.c
new file mode 100644
index 0000000..e58683f
--- /dev/null
+++ b/sys/geom/bde/g_bde_lock.c
@@ -0,0 +1,311 @@
+/*-
+ * 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 souce file contains routines which operates on the lock sectors, both
+ * for the kernel and the userland program gbde(1).
+ *
+ */
+
+#include <sys/param.h>
+#include <sys/queue.h>
+#include <sys/stdint.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/md5.h>
+
+#ifdef _KERNEL
+#include <sys/malloc.h>
+#include <sys/systm.h>
+#else
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#define g_free(foo)	free(foo)
+#endif
+
+#include <geom/geom.h>
+#include <geom/bde/g_bde.h>
+
+#include <crypto/rijndael/rijndael.h>
+
+/*
+ * Encode/Decode the lock structure in byte-sequence format.
+ *
+ * Security objectives:  none.
+ *
+ * C-structure packing and byte-endianess depends on architecture, compiler
+ * and compiler options.  We therefore explicitly encode and decode struct
+ * g_bde_key using an invariant byte-sequence format.
+ *
+ */
+
+void
+g_bde_encode_lock(struct g_bde_key *gl, u_char *ptr)
+{
+
+	bcopy(gl->hash, ptr + 0, sizeof gl->hash);
+	g_enc_le8(ptr +  16, gl->sector0);
+	g_enc_le8(ptr +  24, gl->sectorN);
+	g_enc_le8(ptr +  32, gl->keyoffset);
+	g_enc_le4(ptr +  40, gl->sectorsize);
+	g_enc_le4(ptr +  44, gl->flags);
+	g_enc_le8(ptr +  48, gl->lsector[0]);
+	g_enc_le8(ptr +  56, gl->lsector[1]);
+	g_enc_le8(ptr +  64, gl->lsector[2]);
+	g_enc_le8(ptr +  72, gl->lsector[3]);
+	bcopy(gl->spare, ptr +  80, sizeof gl->spare);
+	bcopy(gl->key, ptr + 128, sizeof gl->key);
+}
+
+void
+g_bde_decode_lock(struct g_bde_key *gl, u_char *ptr)
+{
+	bcopy(ptr + 0, gl->hash, sizeof gl->hash);
+	gl->sector0    = g_dec_le8(ptr +  16);
+	gl->sectorN    = g_dec_le8(ptr +  24);
+	gl->keyoffset  = g_dec_le8(ptr +  32);
+	gl->sectorsize = g_dec_le4(ptr +  40);
+	gl->flags      = g_dec_le4(ptr +  44);
+	gl->lsector[0] = g_dec_le8(ptr +  48);
+	gl->lsector[1] = g_dec_le8(ptr +  56);
+	gl->lsector[2] = g_dec_le8(ptr +  64);
+	gl->lsector[3] = g_dec_le8(ptr +  72);
+	bcopy(ptr +  80, gl->spare, sizeof gl->spare);
+	bcopy(ptr + 128, gl->key, sizeof gl->key);
+}
+
+/*
+ * Generate key-material used for protecting lock sectors.
+ *
+ * Security objectives: from the pass-phrase provide by the user, produce a 
+ * reproducible stream of bits/bytes which resemeble pseudo-random bits.
+ *
+ * This is the stream-cipher algorithm called ARC4.  See for instance the
+ * description in "Applied Cryptography" by Bruce Scneier.
+ */
+
+u_char
+g_bde_arc4(struct g_bde_softc *sc)
+{
+	u_char c;
+
+	sc->arc4_j += sc->arc4_sbox[++sc->arc4_i];
+	c = sc->arc4_sbox[sc->arc4_i];
+	sc->arc4_sbox[sc->arc4_i] = sc->arc4_sbox[sc->arc4_j];
+	sc->arc4_sbox[sc->arc4_j] = c;
+	c = sc->arc4_sbox[sc->arc4_i] + sc->arc4_sbox[sc->arc4_j];
+	c = sc->arc4_sbox[c];
+	return (c);
+}
+
+void
+g_bde_arc4_seq(struct g_bde_softc *sc, void *ptr, u_int len)
+{
+	u_char *p;
+	
+	p = ptr;
+	while (len--)
+		*p++ = g_bde_arc4(sc);
+}
+
+void
+g_bde_arc4_seed(struct g_bde_softc *sc, void *ptr, u_int len)
+{
+	u_char k[256], *p, c;
+	u_int i;
+
+	p = ptr;
+	sc->arc4_i = 0;
+	bzero(k, sizeof k);
+	while(len--)
+		k[sc->arc4_i++] ^= *p++;
+
+	sc->arc4_j = 0;
+	for (i = 0; i < 256; i++) 
+		sc->arc4_sbox[i] = i;
+	for (i = 0; i < 256; i++) {
+		sc->arc4_j += sc->arc4_sbox[i] + k[i];
+		c = sc->arc4_sbox[i];
+		sc->arc4_sbox[i] = sc->arc4_sbox[sc->arc4_j];
+		sc->arc4_sbox[sc->arc4_j] = c;
+	}
+	sc->arc4_i = 0;
+	sc->arc4_j = 0;
+}
+
+/*
+ * Encrypt/Decrypt the metadata address with key-material.
+ */
+
+int
+g_bde_keyloc_encrypt(struct g_bde_softc *sc, void *input, void *output)
+{
+	u_char *p;
+	u_char buf[16], buf1[16];
+	u_int i;
+	keyInstance ki;
+	cipherInstance ci;
+
+	rijndael_cipherInit(&ci, MODE_CBC, NULL);
+	p = input;
+	g_bde_arc4_seq(sc, buf, sizeof buf);
+	for (i = 0; i < sizeof buf; i++)
+		buf1[i] = p[i] ^ buf[i];
+	g_bde_arc4_seq(sc, buf, sizeof buf);
+	rijndael_makeKey(&ki, DIR_ENCRYPT, G_BDE_KKEYBITS, buf);
+	rijndael_blockEncrypt(&ci, &ki, buf1, 16 * 8, output);
+	bzero(&ci, sizeof ci);
+	return (0);
+}
+
+int
+g_bde_keyloc_decrypt(struct g_bde_softc *sc, void *input, void *output)
+{
+	u_char *p;
+	u_char buf1[16], buf2[16];
+	u_int i;
+	keyInstance ki;
+	cipherInstance ci;
+
+	rijndael_cipherInit(&ci, MODE_CBC, NULL);
+	g_bde_arc4_seq(sc, buf1, sizeof buf1);
+	g_bde_arc4_seq(sc, buf2, sizeof buf2);
+	rijndael_makeKey(&ki, DIR_DECRYPT, G_BDE_KKEYBITS, buf2);
+	rijndael_blockDecrypt(&ci, &ki, input, 16 * 8, output);
+	p = output;
+	for (i = 0; i < sizeof buf1; i++)
+		p[i] ^= buf1[i];
+	bzero(&ci, sizeof ci);
+	return (0);
+}
+
+/*
+ * Encode/Decode lock sectors.
+ */
+
+int
+g_bde_decrypt_lock(struct g_bde_softc *sc, u_char *sbox, u_char *meta, off_t mediasize, u_int sectorsize, u_int *nkey)
+{
+	u_char *buf, k1buf[16], k2buf[G_BDE_LOCKSIZE], k3buf[16], *q;
+	struct g_bde_key *gl;
+	uint64_t off[2];
+	int error, m, i;
+	MD5_CTX c;
+	keyInstance ki;
+	cipherInstance ci;
+
+	rijndael_cipherInit(&ci, MODE_CBC, NULL);
+	bcopy(sbox, sc->arc4_sbox, 256);
+	sc->arc4_i = 0;
+	sc->arc4_j = 0;
+	gl = &sc->key;
+	error = g_bde_keyloc_decrypt(sc, meta, off);
+	if (error)
+		return(error);
+
+	if (off[0] + G_BDE_LOCKSIZE > (uint64_t)mediasize) {
+		bzero(off, sizeof off);
+		return (ESRCH);
+	}
+	off[1] = 0;
+	m = 1;
+	if (off[0] % sectorsize > sectorsize - G_BDE_LOCKSIZE)
+		m++;
+	buf = g_read_data(sc->consumer,
+		off[0] - (off[0] % sectorsize),
+		m * sectorsize, &error);
+	if (buf == NULL) {
+		off[0] = 0;
+		return(error);
+	}
+
+	q = buf + off[0] % sectorsize;
+
+	off[1] = 0;
+	for (i = 0; i < (int)sizeof(*gl); i++)
+		off[1] += q[i];
+
+	if (off[1] == 0) {
+		off[0] = 0;
+		g_free(buf);
+		return (ESRCH);
+	}
+
+	g_bde_arc4_seq(sc, k1buf, sizeof k1buf);
+	g_bde_arc4_seq(sc, k2buf, sizeof k2buf);
+	g_bde_arc4_seq(sc, k3buf, sizeof k3buf);
+
+	MD5Init(&c);
+	MD5Update(&c, "0000", 4);	/* XXX: for future versioning */
+	MD5Update(&c, k1buf, 16);
+	MD5Final(k1buf, &c);
+
+	rijndael_makeKey(&ki, DIR_DECRYPT, 128, k3buf);
+	bzero(k3buf, sizeof k3buf);
+	rijndael_blockDecrypt(&ci, &ki, q, G_BDE_LOCKSIZE * 8, q);
+
+	for (i = 0; i < G_BDE_LOCKSIZE; i++)
+		q[i] ^= k2buf[i];
+	bzero(k2buf, sizeof k2buf);
+
+	if (bcmp(q, k1buf, sizeof k1buf)) {
+		bzero(k1buf, sizeof k1buf);
+		bzero(buf, sectorsize * m);
+		g_free(buf);
+		off[0] = 0;
+		return (ESRCH);
+	}
+	bzero(k1buf, sizeof k1buf);
+
+	g_bde_decode_lock(gl, q);
+	bzero(buf, sectorsize * m);
+	g_free(buf);
+
+	off[1] = 0;
+	for (i = 0; i < (int)sizeof(gl->key); i++)
+		off[1] += gl->key[i];
+
+	if (off[1] == 0) {
+		off[0] = 0;
+		return (ENOENT);
+	}
+	for (i = 0; i < G_BDE_MAXKEYS; i++)
+		if (nkey != NULL && off[0] == gl->lsector[i])
+			*nkey = i;
+
+	return (0);
+}