378 lines
9.6 KiB
C
378 lines
9.6 KiB
C
/*-
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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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#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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#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 <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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#define MASTER_KEY_LENGTH (1024/8)
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static const u_char *aes_magic = "<<FreeBSD-GEOM-AES>>";
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static const u_char *aes_magic_random = "<<FreeBSD-GEOM-AES-RANDOM>>";
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static const u_char *aes_magic_test = "<<FreeBSD-GEOM-AES-TEST>>";
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struct g_aes_softc {
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enum {
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KEY_ZERO,
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KEY_RANDOM,
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KEY_TEST
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} keying;
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u_int sectorsize;
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off_t mediasize;
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cipherInstance ci;
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u_char master_key[MASTER_KEY_LENGTH];
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};
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/*
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* Generate a sectorkey from the masterkey and the offset position.
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*
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* For KEY_ZERO we just return a key of all zeros.
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*
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* We feed the sector byte offset, 16 bytes of the master-key and
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* the sector byte offset once more to MD5.
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* The sector byte offset is converted to little-endian format first
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* to support multi-architecture operation.
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* We use 16 bytes from the master-key starting at the logical sector
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* number modulus he length of the master-key. If need be we wrap
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* around to the start of the master-key.
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*/
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static void
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g_aes_makekey(struct g_aes_softc *sc, off_t off, keyInstance *ki, int dir)
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{
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MD5_CTX cx;
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u_int64_t u64;
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u_int u, u1;
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u_char *p, buf[16];
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if (sc->keying == KEY_ZERO) {
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rijndael_makeKey(ki, dir, 128, sc->master_key);
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return;
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}
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MD5Init(&cx);
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u64 = htole64(off);
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MD5Update(&cx, (u_char *)&u64, sizeof(u64));
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u = off / sc->sectorsize;
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u %= sizeof sc->master_key;
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p = sc->master_key + u;
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if (u + 16 <= sizeof(sc->master_key)) {
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MD5Update(&cx, p, 16);
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} else {
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u1 = sizeof sc->master_key - u;
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MD5Update(&cx, p, u1);
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MD5Update(&cx, sc->master_key, 16 - u1);
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u1 = 0; /* destroy evidence */
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}
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u = 0; /* destroy evidence */
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MD5Update(&cx, (u_char *)&u64, sizeof(u64));
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u64 = 0; /* destroy evidence */
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MD5Final(buf, &cx);
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bzero(&cx, sizeof cx); /* destroy evidence */
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rijndael_makeKey(ki, dir, 128, buf);
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bzero(buf, sizeof buf); /* destroy evidence */
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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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keyInstance dkey;
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off_t o;
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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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o = bp->bio_offset - sc->sectorsize;
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for (p = b; p < e; p += sc->sectorsize) {
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g_aes_makekey(sc, o, &dkey, DIR_DECRYPT);
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rijndael_blockDecrypt(&sc->ci, &dkey, p, sc->sectorsize * 8, sb);
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bcopy(sb, p, sc->sectorsize);
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o += sc->sectorsize;
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}
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bzero(&dkey, sizeof dkey); /* destroy evidence */
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bzero(sb, sc->sectorsize); /* destroy evidence */
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g_free(sb);
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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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struct g_aes_softc *sc;
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struct g_geom *gp;
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gp = bp->bio_to->geom;
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sc = gp->softc;
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bzero(bp->bio_data, bp->bio_length); /* destroy evidence */
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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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keyInstance ekey;
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off_t o;
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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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if (bp2 == NULL) {
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g_io_deliver(bp, ENOMEM);
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return;
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}
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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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if (bp2 == NULL) {
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g_io_deliver(bp, ENOMEM);
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return;
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}
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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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o = bp->bio_offset;
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for (p1 = b; p1 < e; p1 += sc->sectorsize) {
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g_aes_makekey(sc, o, &ekey, DIR_ENCRYPT);
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rijndael_blockEncrypt(&sc->ci, &ekey,
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p1, sc->sectorsize * 8, p2);
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p2 += sc->sectorsize;
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o += sc->sectorsize;
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}
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bzero(&ekey, sizeof ekey); /* destroy evidence */
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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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bp2 = g_clone_bio(bp);
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if (bp2 == NULL) {
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g_io_deliver(bp, ENOMEM);
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return;
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}
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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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g_io_deliver(bp, EOPNOTSUPP);
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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_aes_softc *sc;
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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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sc = gp->softc;
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g_wither_geom(gp, cp->provider->error);
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bzero(sc, sizeof(struct g_aes_softc)); /* destroy evidence */
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g_free(sc);
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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_detach(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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g_topology_unlock();
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do {
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if (gp->rank != 2)
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break;
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sectorsize = cp->provider->sectorsize;
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mediasize = cp->provider->mediasize;
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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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sc = g_malloc(sizeof(struct g_aes_softc), M_WAITOK | M_ZERO);
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if (!memcmp(buf, aes_magic, strlen(aes_magic))) {
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sc->keying = KEY_ZERO;
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} else if (!memcmp(buf, aes_magic_random,
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strlen(aes_magic_random))) {
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sc->keying = KEY_RANDOM;
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} else if (!memcmp(buf, aes_magic_test,
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strlen(aes_magic_test))) {
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sc->keying = KEY_TEST;
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} else {
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g_free(sc);
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break;
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}
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g_free(buf);
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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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if (sc->keying == KEY_TEST) {
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int i;
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u_char *p;
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p = sc->master_key;
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for (i = 0; i < (int)sizeof sc->master_key; i ++)
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*p++ = i;
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}
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if (sc->keying == KEY_RANDOM) {
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int i;
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u_int32_t u;
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u_char *p;
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p = sc->master_key;
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for (i = 0; i < (int)sizeof sc->master_key; i += sizeof u) {
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u = arc4random();
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*p++ = u;
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*p++ = u >> 8;
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*p++ = u >> 16;
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*p++ = u >> 24;
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}
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}
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g_topology_lock();
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pp = g_new_providerf(gp, gp->name);
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pp->mediasize = mediasize - sectorsize;
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pp->sectorsize = sectorsize;
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g_error_provider(pp, 0);
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g_topology_unlock();
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} while(0);
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g_topology_lock();
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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_detach(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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.name = AES_CLASS_NAME,
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.taste = g_aes_taste,
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};
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DECLARE_GEOM_CLASS(g_aes_class, g_aes);
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