geom_aes.c

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    1 /*-
    2  * Copyright (c) 2002 Poul-Henning Kamp
    3  * Copyright (c) 2002 Networks Associates Technology, Inc.
    4  * All rights reserved.
    5  *
    6  * This software was developed for the FreeBSD Project by Poul-Henning Kamp
    7  * and NAI Labs, the Security Research Division of Network Associates, Inc.
    8  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
    9  * DARPA CHATS research program.
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   14  * 1. Redistributions of source code must retain the above copyright
   15  *    notice, this list of conditions and the following disclaimer.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  * 3. The names of the authors may not be used to endorse or promote
   20  *    products derived from this software without specific prior written
   21  *    permission.
   22  *
   23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   33  * SUCH DAMAGE.
   34  */
   35 
   36 /*
   37  * This method provides AES encryption with a compiled in key (default
   38  * all zeroes).
   39  *
   40  * XXX: This could probably save a lot of code by pretending to be a slicer.
   41  */
   42 
   43 #include <sys/cdefs.h>
   44 __FBSDID("$FreeBSD$");
   45 
   46 #include <sys/param.h>
   47 #include <sys/systm.h>
   48 #include <sys/kernel.h>
   49 #include <sys/conf.h>
   50 #include <sys/bio.h>
   51 #include <sys/malloc.h>
   52 #include <sys/lock.h>
   53 #include <sys/mutex.h>
   54 #include <sys/libkern.h>
   55 #include <sys/endian.h>
   56 #include <sys/md5.h>
   57 #include <sys/errno.h>
   58 #include <geom/geom.h>
   59 
   60 #include <crypto/rijndael/rijndael-api-fst.h>
   61 
   62 #define AES_CLASS_NAME "AES"
   63 
   64 #define MASTER_KEY_LENGTH       (1024/8)
   65 
   66 static const u_char *aes_magic = "<<FreeBSD-GEOM-AES>>";
   67 static const u_char *aes_magic_random = "<<FreeBSD-GEOM-AES-RANDOM>>";
   68 static const u_char *aes_magic_test = "<<FreeBSD-GEOM-AES-TEST>>";
   69 
   70 static int g_aes_once;
   71 
   72 struct g_aes_softc {
   73         enum {
   74                 KEY_ZERO,
   75                 KEY_RANDOM,
   76                 KEY_TEST
   77         } keying;
   78         u_int   sectorsize;
   79         off_t   mediasize;
   80         cipherInstance ci;
   81         u_char master_key[MASTER_KEY_LENGTH];
   82 };
   83 
   84 /*
   85  * Generate a sectorkey from the masterkey and the offset position.
   86  *
   87  * For KEY_ZERO we just return a key of all zeros.
   88  *
   89  * We feed the sector byte offset, 16 bytes of the master-key and
   90  * the sector byte offset once more to MD5.
   91  * The sector byte offset is converted to little-endian format first
   92  * to support multi-architecture operation.
   93  * We use 16 bytes from the master-key starting at the logical sector
   94  * number modulus he length of the master-key.  If need be we wrap
   95  * around to the start of the master-key.
   96  */
   97 
   98 static void
   99 g_aes_makekey(struct g_aes_softc *sc, off_t off, keyInstance *ki, int dir)
  100 {
  101         MD5_CTX cx;
  102         u_int64_t u64;
  103         u_int u, u1;
  104         u_char *p, buf[16];
  105 
  106         if (sc->keying == KEY_ZERO) {
  107                 rijndael_makeKey(ki, dir, 128, sc->master_key);
  108                 return;
  109         }
  110         MD5Init(&cx);
  111         u64 = htole64(off);
  112         MD5Update(&cx, (u_char *)&u64, sizeof(u64));
  113         u = off / sc->sectorsize;
  114         u %= sizeof sc->master_key;
  115         p = sc->master_key + u;
  116         if (u + 16 <= sizeof(sc->master_key)) {
  117                 MD5Update(&cx, p, 16);
  118         } else {
  119                 u1 = sizeof sc->master_key - u;
  120                 MD5Update(&cx, p, u1);
  121                 MD5Update(&cx, sc->master_key, 16 - u1);
  122                 u1 = 0;                         /* destroy evidence */
  123         }
  124         u = 0;                                  /* destroy evidence */
  125         MD5Update(&cx, (u_char *)&u64, sizeof(u64));
  126         u64 = 0;                                /* destroy evidence */
  127         MD5Final(buf, &cx);
  128         bzero(&cx, sizeof cx);                  /* destroy evidence */
  129         rijndael_makeKey(ki, dir, 128, buf);
  130         bzero(buf, sizeof buf);                 /* destroy evidence */
  131 
  132 }
  133 
  134 static void
  135 g_aes_read_done(struct bio *bp)
  136 {
  137         struct g_geom *gp;
  138         struct g_aes_softc *sc;
  139         u_char *p, *b, *e, *sb;
  140         keyInstance dkey;
  141         off_t o;
  142 
  143         gp = bp->bio_from->geom;
  144         sc = gp->softc;
  145         sb = g_malloc(sc->sectorsize, M_WAITOK);
  146         b = bp->bio_data;
  147         e = bp->bio_data;
  148         e += bp->bio_length;
  149         o = bp->bio_offset - sc->sectorsize;
  150         for (p = b; p < e; p += sc->sectorsize) {
  151                 g_aes_makekey(sc, o, &dkey, DIR_DECRYPT);
  152                 rijndael_blockDecrypt(&sc->ci, &dkey, p, sc->sectorsize * 8, sb);
  153                 bcopy(sb, p, sc->sectorsize);
  154                 o += sc->sectorsize;
  155         }
  156         bzero(&dkey, sizeof dkey);              /* destroy evidence */
  157         bzero(sb, sc->sectorsize);              /* destroy evidence */
  158         g_free(sb);
  159         g_std_done(bp);
  160 }
  161 
  162 static void
  163 g_aes_write_done(struct bio *bp)
  164 {
  165 
  166         bzero(bp->bio_data, bp->bio_length);    /* destroy evidence */
  167         g_free(bp->bio_data);
  168         g_std_done(bp);
  169 }
  170 
  171 static void
  172 g_aes_start(struct bio *bp)
  173 {
  174         struct g_geom *gp;
  175         struct g_consumer *cp;
  176         struct g_aes_softc *sc;
  177         struct bio *bp2;
  178         u_char *p1, *p2, *b, *e;
  179         keyInstance ekey;
  180         off_t o;
  181 
  182         gp = bp->bio_to->geom;
  183         cp = LIST_FIRST(&gp->consumer);
  184         sc = gp->softc;
  185         switch (bp->bio_cmd) {
  186         case BIO_READ:
  187                 bp2 = g_clone_bio(bp);
  188                 if (bp2 == NULL) {
  189                         g_io_deliver(bp, ENOMEM);
  190                         return;
  191                 }
  192                 bp2->bio_done = g_aes_read_done;
  193                 bp2->bio_offset += sc->sectorsize;
  194                 g_io_request(bp2, cp);
  195                 break;
  196         case BIO_WRITE:
  197                 bp2 = g_clone_bio(bp);
  198                 if (bp2 == NULL) {
  199                         g_io_deliver(bp, ENOMEM);
  200                         return;
  201                 }
  202                 bp2->bio_done = g_aes_write_done;
  203                 bp2->bio_offset += sc->sectorsize;
  204                 bp2->bio_data = g_malloc(bp->bio_length, M_WAITOK);
  205                 b = bp->bio_data;
  206                 e = bp->bio_data;
  207                 e += bp->bio_length;
  208                 p2 = bp2->bio_data;
  209                 o = bp->bio_offset;
  210                 for (p1 = b; p1 < e; p1 += sc->sectorsize) {
  211                         g_aes_makekey(sc, o, &ekey, DIR_ENCRYPT);
  212                         rijndael_blockEncrypt(&sc->ci, &ekey,
  213                             p1, sc->sectorsize * 8, p2);
  214                         p2 += sc->sectorsize;
  215                         o += sc->sectorsize;
  216                 }
  217                 bzero(&ekey, sizeof ekey);      /* destroy evidence */
  218                 g_io_request(bp2, cp);
  219                 break;
  220         case BIO_GETATTR:
  221                 bp2 = g_clone_bio(bp);
  222                 if (bp2 == NULL) {
  223                         g_io_deliver(bp, ENOMEM);
  224                         return;
  225                 }
  226                 bp2->bio_done = g_std_done;
  227                 bp2->bio_offset += sc->sectorsize;
  228                 g_io_request(bp2, cp);
  229                 break;
  230         default:
  231                 g_io_deliver(bp, EOPNOTSUPP);
  232                 return;
  233         }
  234         return;
  235 }
  236 
  237 static void
  238 g_aes_orphan(struct g_consumer *cp)
  239 {
  240         struct g_geom *gp;
  241         struct g_aes_softc *sc;
  242 
  243         g_trace(G_T_TOPOLOGY, "g_aes_orphan(%p/%s)", cp, cp->provider->name);
  244         g_topology_assert();
  245 
  246         gp = cp->geom;
  247         sc = gp->softc;
  248         g_wither_geom(gp, ENXIO);
  249         bzero(sc, sizeof(struct g_aes_softc));  /* destroy evidence */
  250         g_free(sc);
  251         return;
  252 }
  253 
  254 static int
  255 g_aes_access(struct g_provider *pp, int dr, int dw, int de)
  256 {
  257         struct g_geom *gp;
  258         struct g_consumer *cp;
  259 
  260         gp = pp->geom;
  261         cp = LIST_FIRST(&gp->consumer);
  262         /* On first open, grab an extra "exclusive" bit */
  263         if (cp->acr == 0 && cp->acw == 0 && cp->ace == 0)
  264                 de++;
  265         /* ... and let go of it on last close */
  266         if ((cp->acr + dr) == 0 && (cp->acw + dw) == 0 && (cp->ace + de) == 1)
  267                 de--;
  268         return (g_access(cp, dr, dw, de));
  269 }
  270 
  271 static struct g_geom *
  272 g_aes_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
  273 {
  274         struct g_geom *gp;
  275         struct g_consumer *cp;
  276         struct g_aes_softc *sc;
  277         int error;
  278         u_int sectorsize;
  279         off_t mediasize;
  280         u_char *buf;
  281 
  282         g_trace(G_T_TOPOLOGY, "aes_taste(%s,%s)", mp->name, pp->name);
  283         g_topology_assert();
  284         gp = g_new_geomf(mp, "%s.aes", pp->name);
  285         cp = g_new_consumer(gp);
  286         g_attach(cp, pp);
  287         error = g_access(cp, 1, 0, 0);
  288         if (error) {
  289                 g_detach(cp);
  290                 g_destroy_consumer(cp);
  291                 g_destroy_geom(gp);
  292                 return (NULL);
  293         }
  294         buf = NULL;
  295         g_topology_unlock();
  296         do {
  297                 if (gp->rank != 2)
  298                         break;
  299                 sectorsize = cp->provider->sectorsize;
  300                 mediasize = cp->provider->mediasize;
  301                 buf = g_read_data(cp, 0, sectorsize, NULL);
  302                 if (buf == NULL) {
  303                         break;
  304                 }
  305                 sc = g_malloc(sizeof(struct g_aes_softc), M_WAITOK | M_ZERO);
  306                 if (!memcmp(buf, aes_magic, strlen(aes_magic))) {
  307                         sc->keying = KEY_ZERO;
  308                 } else if (!memcmp(buf, aes_magic_random, 
  309                     strlen(aes_magic_random))) {
  310                         sc->keying = KEY_RANDOM;
  311                 } else if (!memcmp(buf, aes_magic_test, 
  312                     strlen(aes_magic_test))) {
  313                         sc->keying = KEY_TEST;
  314                 } else {
  315                         g_free(sc);
  316                         break;
  317                 }
  318                 g_free(buf);
  319                 gp->softc = sc;
  320                 sc->sectorsize = sectorsize;
  321                 sc->mediasize = mediasize - sectorsize;
  322                 rijndael_cipherInit(&sc->ci, MODE_CBC, NULL);
  323                 if (sc->keying == KEY_TEST) {
  324                         int i;
  325                         u_char *p;
  326 
  327                         p = sc->master_key;
  328                         for (i = 0; i < (int)sizeof sc->master_key; i ++) 
  329                                 *p++ = i;
  330                 }
  331                 if (sc->keying == KEY_RANDOM) {
  332                         int i;
  333                         u_int32_t u;
  334                         u_char *p;
  335 
  336                         p = sc->master_key;
  337                         for (i = 0; i < (int)sizeof sc->master_key; i += sizeof u) {
  338                                 u = arc4random();
  339                                 *p++ = u;
  340                                 *p++ = u >> 8;
  341                                 *p++ = u >> 16;
  342                                 *p++ = u >> 24;
  343                         }
  344                 }
  345                 g_topology_lock();
  346                 pp = g_new_providerf(gp, "%s", gp->name);
  347                 pp->mediasize = mediasize - sectorsize;
  348                 pp->sectorsize = sectorsize;
  349                 g_error_provider(pp, 0);
  350                 g_topology_unlock();
  351         } while(0);
  352         g_topology_lock();
  353         if (buf)
  354                 g_free(buf);
  355         g_access(cp, -1, 0, 0);
  356         if (gp->softc != NULL) {
  357                 if (!g_aes_once) {
  358                         g_aes_once = 1;
  359                         printf("WARNING: geom_aes (geom %s) is deprecated.",
  360                             gp->name);
  361                 }
  362                 return (gp);
  363         }
  364         g_detach(cp);
  365         g_destroy_consumer(cp);
  366         g_destroy_geom(gp);
  367         return (NULL);
  368 }
  369 
  370 static struct g_class g_aes_class       = {
  371         .name = AES_CLASS_NAME,
  372         .version = G_VERSION,
  373         .taste = g_aes_taste,
  374         .start = g_aes_start,
  375         .orphan = g_aes_orphan,
  376         .spoiled = g_std_spoiled,
  377         .access = g_aes_access,
  378 };
  379 
  380 DECLARE_GEOM_CLASS(g_aes_class, g_aes);
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FreeBSD/Linux Kernel Cross Reference sys/geom/geom_aes.c

FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_aes.c
