2 * Copyright (c) 2011 Pawel Jakub Dawidek <pawel@dawidek.net>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
31 #include <sys/kernel.h>
32 #include <sys/malloc.h>
33 #include <sys/queue.h>
34 #include <sys/sysctl.h>
35 #include <sys/systm.h>
38 #include <geom/geom.h>
40 #include <geom/eli/g_eli.h>
42 MALLOC_DECLARE(M_ELI);
44 SYSCTL_DECL(_kern_geom_eli);
46 * The default limit (8192 keys) will allow to cache all keys for 4TB
47 * provider with 512 bytes sectors and will take around 1MB of memory.
49 static u_int g_eli_key_cache_limit = 8192;
50 TUNABLE_INT("kern.geom.eli.key_cache_limit", &g_eli_key_cache_limit);
51 SYSCTL_UINT(_kern_geom_eli, OID_AUTO, key_cache_limit, CTLFLAG_RDTUN,
52 &g_eli_key_cache_limit, 0, "Maximum number of encryption keys to cache");
53 static uint64_t g_eli_key_cache_hits;
54 SYSCTL_UQUAD(_kern_geom_eli, OID_AUTO, key_cache_hits, CTLFLAG_RW,
55 &g_eli_key_cache_hits, 0, "Key cache hits");
56 static uint64_t g_eli_key_cache_misses;
57 SYSCTL_UQUAD(_kern_geom_eli, OID_AUTO, key_cache_misses, CTLFLAG_RW,
58 &g_eli_key_cache_misses, 0, "Key cache misses");
60 #define G_ELI_KEY_MAGIC 0xe11341c
63 /* Key value, must be first in the structure. */
64 uint8_t gek_key[G_ELI_DATAKEYLEN];
69 /* Reference counter. */
71 /* Keeps keys sorted by most recent use. */
72 TAILQ_ENTRY(g_eli_key) gek_next;
73 /* Keeps keys sorted by number. */
74 RB_ENTRY(g_eli_key) gek_link;
78 g_eli_key_cmp(const struct g_eli_key *a, const struct g_eli_key *b)
81 if (a->gek_keyno > b->gek_keyno)
83 else if (a->gek_keyno < b->gek_keyno)
88 RB_PROTOTYPE(g_eli_key_tree, g_eli_key, gek_link, g_eli_key_cmp);
89 RB_GENERATE(g_eli_key_tree, g_eli_key, gek_link, g_eli_key_cmp);
92 g_eli_key_fill(struct g_eli_softc *sc, struct g_eli_key *key, uint64_t keyno)
99 bcopy("ekey", hmacdata.magic, 4);
100 le64enc(hmacdata.keyno, keyno);
101 g_eli_crypto_hmac(sc->sc_mkey, G_ELI_MAXKEYLEN, (uint8_t *)&hmacdata,
102 sizeof(hmacdata), key->gek_key, 0);
103 key->gek_keyno = keyno;
105 key->gek_magic = G_ELI_KEY_MAGIC;
108 static struct g_eli_key *
109 g_eli_key_allocate(struct g_eli_softc *sc, uint64_t keyno)
111 struct g_eli_key *key, *ekey, keysearch;
113 mtx_assert(&sc->sc_ekeys_lock, MA_OWNED);
114 mtx_unlock(&sc->sc_ekeys_lock);
116 key = malloc(sizeof(*key), M_ELI, M_WAITOK);
117 g_eli_key_fill(sc, key, keyno);
119 mtx_lock(&sc->sc_ekeys_lock);
121 * Recheck if the key wasn't added while we weren't holding the lock.
123 keysearch.gek_keyno = keyno;
124 ekey = RB_FIND(g_eli_key_tree, &sc->sc_ekeys_tree, &keysearch);
126 bzero(key, sizeof(*key));
129 TAILQ_REMOVE(&sc->sc_ekeys_queue, key, gek_next);
131 RB_INSERT(g_eli_key_tree, &sc->sc_ekeys_tree, key);
132 sc->sc_ekeys_allocated++;
134 TAILQ_INSERT_TAIL(&sc->sc_ekeys_queue, key, gek_next);
139 static struct g_eli_key *
140 g_eli_key_find_last(struct g_eli_softc *sc)
142 struct g_eli_key *key;
144 mtx_assert(&sc->sc_ekeys_lock, MA_OWNED);
146 TAILQ_FOREACH(key, &sc->sc_ekeys_queue, gek_next) {
147 if (key->gek_count == 0)
155 g_eli_key_replace(struct g_eli_softc *sc, struct g_eli_key *key, uint64_t keyno)
158 mtx_assert(&sc->sc_ekeys_lock, MA_OWNED);
159 KASSERT(key->gek_magic == G_ELI_KEY_MAGIC, ("Invalid magic."));
161 RB_REMOVE(g_eli_key_tree, &sc->sc_ekeys_tree, key);
162 TAILQ_REMOVE(&sc->sc_ekeys_queue, key, gek_next);
164 KASSERT(key->gek_count == 0, ("gek_count=%d", key->gek_count));
166 g_eli_key_fill(sc, key, keyno);
168 RB_INSERT(g_eli_key_tree, &sc->sc_ekeys_tree, key);
169 TAILQ_INSERT_TAIL(&sc->sc_ekeys_queue, key, gek_next);
173 g_eli_key_remove(struct g_eli_softc *sc, struct g_eli_key *key)
176 mtx_assert(&sc->sc_ekeys_lock, MA_OWNED);
177 KASSERT(key->gek_magic == G_ELI_KEY_MAGIC, ("Invalid magic."));
178 KASSERT(key->gek_count == 0, ("gek_count=%d", key->gek_count));
180 RB_REMOVE(g_eli_key_tree, &sc->sc_ekeys_tree, key);
181 TAILQ_REMOVE(&sc->sc_ekeys_queue, key, gek_next);
182 sc->sc_ekeys_allocated--;
183 bzero(key, sizeof(*key));
188 g_eli_key_init(struct g_eli_softc *sc)
191 mtx_lock(&sc->sc_ekeys_lock);
192 if ((sc->sc_flags & G_ELI_FLAG_SINGLE_KEY) != 0) {
195 mkey = sc->sc_mkey + sizeof(sc->sc_ivkey);
197 sc->sc_ekeys_total = 1;
198 sc->sc_ekeys_allocated = 0;
199 if ((sc->sc_flags & G_ELI_FLAG_AUTH) == 0)
200 bcopy(mkey, sc->sc_ekey, G_ELI_DATAKEYLEN);
203 * The encryption key is: ekey = HMAC_SHA512(Master-Key, 0x10)
205 g_eli_crypto_hmac(mkey, G_ELI_MAXKEYLEN, "\x10", 1,
212 if ((sc->sc_flags & G_ELI_FLAG_AUTH) != 0) {
213 struct g_provider *pp;
215 pp = LIST_FIRST(&sc->sc_geom->consumer)->provider;
216 mediasize = pp->mediasize;
217 blocksize = pp->sectorsize;
219 mediasize = sc->sc_mediasize;
220 blocksize = sc->sc_sectorsize;
223 ((mediasize - 1) >> G_ELI_KEY_SHIFT) / blocksize + 1;
224 sc->sc_ekeys_allocated = 0;
225 TAILQ_INIT(&sc->sc_ekeys_queue);
226 RB_INIT(&sc->sc_ekeys_tree);
227 if (sc->sc_ekeys_total <= g_eli_key_cache_limit) {
230 for (keyno = 0; keyno < sc->sc_ekeys_total; keyno++)
231 (void)g_eli_key_allocate(sc, keyno);
232 KASSERT(sc->sc_ekeys_total == sc->sc_ekeys_allocated,
233 ("sc_ekeys_total=%ju != sc_ekeys_allocated=%ju",
234 (uintmax_t)sc->sc_ekeys_total,
235 (uintmax_t)sc->sc_ekeys_allocated));
238 mtx_unlock(&sc->sc_ekeys_lock);
242 g_eli_key_destroy(struct g_eli_softc *sc)
245 mtx_lock(&sc->sc_ekeys_lock);
246 if ((sc->sc_flags & G_ELI_FLAG_SINGLE_KEY) != 0) {
247 bzero(sc->sc_ekey, sizeof(sc->sc_ekey));
249 struct g_eli_key *key;
251 while ((key = TAILQ_FIRST(&sc->sc_ekeys_queue)) != NULL)
252 g_eli_key_remove(sc, key);
253 TAILQ_INIT(&sc->sc_ekeys_queue);
254 RB_INIT(&sc->sc_ekeys_tree);
256 mtx_unlock(&sc->sc_ekeys_lock);
260 * Select encryption key. If G_ELI_FLAG_SINGLE_KEY is present we only have one
261 * key available for all the data. If the flag is not present select the key
262 * based on data offset.
265 g_eli_key_hold(struct g_eli_softc *sc, off_t offset, size_t blocksize)
267 struct g_eli_key *key, keysearch;
270 if ((sc->sc_flags & G_ELI_FLAG_SINGLE_KEY) != 0)
271 return (sc->sc_ekey);
273 /* We switch key every 2^G_ELI_KEY_SHIFT blocks. */
274 keyno = (offset >> G_ELI_KEY_SHIFT) / blocksize;
276 KASSERT(keyno < sc->sc_ekeys_total,
277 ("%s: keyno=%ju >= sc_ekeys_total=%ju",
278 __func__, (uintmax_t)keyno, (uintmax_t)sc->sc_ekeys_total));
280 keysearch.gek_keyno = keyno;
282 if (sc->sc_ekeys_total == sc->sc_ekeys_allocated) {
283 /* We have all the keys, so avoid some overhead. */
284 key = RB_FIND(g_eli_key_tree, &sc->sc_ekeys_tree, &keysearch);
285 KASSERT(key != NULL, ("No key %ju found.", (uintmax_t)keyno));
286 KASSERT(key->gek_magic == G_ELI_KEY_MAGIC,
287 ("Invalid key magic."));
288 return (key->gek_key);
291 mtx_lock(&sc->sc_ekeys_lock);
292 key = RB_FIND(g_eli_key_tree, &sc->sc_ekeys_tree, &keysearch);
294 g_eli_key_cache_hits++;
295 TAILQ_REMOVE(&sc->sc_ekeys_queue, key, gek_next);
296 TAILQ_INSERT_TAIL(&sc->sc_ekeys_queue, key, gek_next);
299 * No key in cache, find the least recently unreferenced key
300 * or allocate one if we haven't reached our limit yet.
302 if (sc->sc_ekeys_allocated < g_eli_key_cache_limit) {
303 key = g_eli_key_allocate(sc, keyno);
305 g_eli_key_cache_misses++;
306 key = g_eli_key_find_last(sc);
308 g_eli_key_replace(sc, key, keyno);
310 /* All keys are referenced? Allocate one. */
311 key = g_eli_key_allocate(sc, keyno);
316 mtx_unlock(&sc->sc_ekeys_lock);
318 KASSERT(key->gek_magic == G_ELI_KEY_MAGIC, ("Invalid key magic."));
320 return (key->gek_key);
324 g_eli_key_drop(struct g_eli_softc *sc, uint8_t *rawkey)
326 struct g_eli_key *key = (struct g_eli_key *)rawkey;
328 if ((sc->sc_flags & G_ELI_FLAG_SINGLE_KEY) != 0)
331 KASSERT(key->gek_magic == G_ELI_KEY_MAGIC, ("Invalid key magic."));
333 if (sc->sc_ekeys_total == sc->sc_ekeys_allocated)
336 mtx_lock(&sc->sc_ekeys_lock);
337 KASSERT(key->gek_count > 0, ("key->gek_count=%d", key->gek_count));
339 while (sc->sc_ekeys_allocated > g_eli_key_cache_limit) {
340 key = g_eli_key_find_last(sc);
343 g_eli_key_remove(sc, key);
345 mtx_unlock(&sc->sc_ekeys_lock);