Add two new submodes to the AES encryption method.
This method is now suitable for encrypting swap spaces. Sponsored by: DARPA & NAI Labs.
This commit is contained in:
Poul-Henning Kamp
parent
2e8c6713e6
commit
77f6a083fc
@ -55,6 +55,9 @@
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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/md5.h>
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#include <sys/endian.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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@ -65,26 +68,83 @@
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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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#define MASTER_KEY_LENGTH (1024/8)
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static u_char *aes_magic = "<<FreeBSD-GEOM-AES>>";
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static u_char *aes_magic_random = "<<FreeBSD-GEOM-AES-RANDOM>>";
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static u_char *aes_magic_test = "<<FreeBSD-GEOM-AES-TEST>>";
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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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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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keyInstance ekey;
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keyInstance dkey;
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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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@ -92,17 +152,28 @@ g_aes_read_done(struct bio *bp)
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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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rijndael_blockDecrypt(&sc->ci, &sc->dkey, p, sc->sectorsize * 8, sb);
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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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@ -115,6 +186,8 @@ g_aes_start(struct bio *bp)
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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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@ -135,11 +208,15 @@ g_aes_start(struct bio *bp)
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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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rijndael_blockEncrypt(&sc->ci, &sc->ekey,
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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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@ -166,6 +243,7 @@ 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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struct g_aes_softc *sc;
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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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@ -174,10 +252,12 @@ g_aes_orphan(struct g_consumer *cp)
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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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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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bzero(sc, sizeof(struct g_aes_softc)); /* destroy evidence */
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return;
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}
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@ -238,16 +318,46 @@ g_aes_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
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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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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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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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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 < 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 < 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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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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