2 * Copyright (c) 2000-2015 Mark R V Murray
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 * in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
31 #include <sys/param.h>
32 #include <sys/systm.h>
35 #include <sys/fcntl.h>
36 #include <sys/filio.h>
37 #include <sys/kernel.h>
38 #include <sys/kthread.h>
40 #include <sys/module.h>
41 #include <sys/malloc.h>
44 #include <sys/random.h>
46 #include <sys/selinfo.h>
47 #include <sys/sysctl.h>
48 #include <sys/systm.h>
50 #include <sys/unistd.h>
52 #include <crypto/rijndael/rijndael-api-fst.h>
53 #include <crypto/sha2/sha256.h>
55 #include <dev/random/hash.h>
56 #include <dev/random/randomdev.h>
57 #include <dev/random/random_harvestq.h>
61 #if defined(RANDOM_LOADABLE)
62 #define READ_RANDOM_UIO _read_random_uio
63 #define READ_RANDOM _read_random
64 static int READ_RANDOM_UIO(struct uio *, bool);
65 static u_int READ_RANDOM(void *, u_int);
67 #define READ_RANDOM_UIO read_random_uio
68 #define READ_RANDOM read_random
71 /* Return the largest number >= x that is a multiple of m */
72 #define CEIL_TO_MULTIPLE(x, m) ((((x) + (m) - 1)/(m))*(m))
74 static d_read_t randomdev_read;
75 static d_write_t randomdev_write;
76 static d_poll_t randomdev_poll;
77 static d_ioctl_t randomdev_ioctl;
79 static struct cdevsw random_cdevsw = {
81 .d_version = D_VERSION,
82 .d_read = randomdev_read,
83 .d_write = randomdev_write,
84 .d_poll = randomdev_poll,
85 .d_ioctl = randomdev_ioctl,
88 /* For use with make_dev(9)/destroy_dev(9). */
89 static struct cdev *random_dev;
92 random_alg_context_ra_init_alg(void *data)
95 p_random_alg_context = &random_alg_context;
96 p_random_alg_context->ra_init_alg(data);
97 #if defined(RANDOM_LOADABLE)
98 random_infra_init(READ_RANDOM_UIO, READ_RANDOM);
103 random_alg_context_ra_deinit_alg(void *data)
106 #if defined(RANDOM_LOADABLE)
107 random_infra_uninit();
109 p_random_alg_context->ra_deinit_alg(data);
110 p_random_alg_context = NULL;
113 SYSINIT(random_device, SI_SUB_RANDOM, SI_ORDER_THIRD, random_alg_context_ra_init_alg, NULL);
114 SYSUNINIT(random_device, SI_SUB_RANDOM, SI_ORDER_THIRD, random_alg_context_ra_deinit_alg, NULL);
116 static struct selinfo rsel;
119 * This is the read uio(9) interface for random(4).
123 randomdev_read(struct cdev *dev __unused, struct uio *uio, int flags)
126 return (READ_RANDOM_UIO(uio, (flags & O_NONBLOCK) != 0));
130 READ_RANDOM_UIO(struct uio *uio, bool nonblock)
133 int error, spamcount;
134 ssize_t read_len, total_read, c;
136 random_buf = malloc(PAGE_SIZE, M_ENTROPY, M_WAITOK);
137 p_random_alg_context->ra_pre_read();
140 /* (Un)Blocking logic */
141 while (!p_random_alg_context->ra_seeded()) {
146 /* keep tapping away at the pre-read until we seed/unblock. */
147 p_random_alg_context->ra_pre_read();
148 /* Only bother the console every 10 seconds or so */
150 printf("random: %s unblock wait\n", __func__);
151 spamcount = (spamcount + 1)%100;
152 error = tsleep(&random_alg_context, PCATCH, "randseed", hz/10);
153 if (error == ERESTART || error == EINTR)
157 read_rate_increment((uio->uio_resid + sizeof(uint32_t))/sizeof(uint32_t));
159 while (uio->uio_resid && !error) {
160 read_len = uio->uio_resid;
163 * Round up the read length to a crypto block size multiple,
164 * which is what the underlying generator is expecting.
165 * See the random_buf size requirements in the Yarrow/Fortuna code.
167 read_len = CEIL_TO_MULTIPLE(read_len, RANDOM_BLOCKSIZE);
168 /* Work in chunks page-sized or less */
169 read_len = MIN(read_len, PAGE_SIZE);
170 p_random_alg_context->ra_read(random_buf, read_len);
171 c = MIN(uio->uio_resid, read_len);
172 error = uiomove(random_buf, c, uio);
175 if (total_read != uio->uio_resid && (error == ERESTART || error == EINTR))
176 /* Return partial read, not error. */
179 free(random_buf, M_ENTROPY);
184 * Kernel API version of read_random().
185 * This is similar to random_alg_read(),
186 * except it doesn't interface with uio(9).
187 * It cannot assumed that random_buf is a multiple of
188 * RANDOM_BLOCKSIZE bytes.
191 READ_RANDOM(void *random_buf, u_int len)
194 uint8_t local_buf[len + RANDOM_BLOCKSIZE];
196 KASSERT(random_buf != NULL, ("No suitable random buffer in %s", __func__));
197 p_random_alg_context->ra_pre_read();
198 /* (Un)Blocking logic; if not seeded, return nothing. */
199 if (p_random_alg_context->ra_seeded()) {
200 read_rate_increment((len + sizeof(uint32_t))/sizeof(uint32_t));
204 * Round up the read length to a crypto block size multiple,
205 * which is what the underlying generator is expecting.
207 read_len = CEIL_TO_MULTIPLE(len, RANDOM_BLOCKSIZE);
208 p_random_alg_context->ra_read(local_buf, read_len);
209 memcpy(random_buf, local_buf, len);
217 randomdev_accumulate(uint8_t *buf, u_int count)
219 static u_int destination = 0;
220 static struct harvest_event event;
221 static struct randomdev_hash hash;
222 static uint32_t entropy_data[RANDOM_KEYSIZE_WORDS];
226 /* Extra timing here is helpful to scrape scheduler jitter entropy */
227 randomdev_hash_init(&hash);
228 timestamp = (uint32_t)get_cyclecount();
229 randomdev_hash_iterate(&hash, ×tamp, sizeof(timestamp));
230 randomdev_hash_iterate(&hash, buf, count);
231 timestamp = (uint32_t)get_cyclecount();
232 randomdev_hash_iterate(&hash, ×tamp, sizeof(timestamp));
233 randomdev_hash_finish(&hash, entropy_data);
234 explicit_bzero(&hash, sizeof(hash));
235 for (i = 0; i < RANDOM_KEYSIZE_WORDS; i += sizeof(event.he_entropy)/sizeof(event.he_entropy[0])) {
236 event.he_somecounter = (uint32_t)get_cyclecount();
237 event.he_size = sizeof(event.he_entropy);
238 event.he_bits = event.he_size/8;
239 event.he_source = RANDOM_CACHED;
240 event.he_destination = destination++; /* Harmless cheating */
241 memcpy(event.he_entropy, entropy_data + i, sizeof(event.he_entropy));
242 p_random_alg_context->ra_event_processor(&event);
244 explicit_bzero(entropy_data, sizeof(entropy_data));
249 randomdev_write(struct cdev *dev __unused, struct uio *uio, int flags __unused)
255 random_buf = malloc(PAGE_SIZE, M_ENTROPY, M_WAITOK);
256 nbytes = uio->uio_resid;
257 while (uio->uio_resid > 0 && error == 0) {
258 c = MIN(uio->uio_resid, PAGE_SIZE);
259 error = uiomove(random_buf, c, uio);
262 randomdev_accumulate(random_buf, c);
263 tsleep(&random_alg_context, 0, "randwr", hz/10);
265 if (nbytes != uio->uio_resid && (error == ERESTART || error == EINTR))
266 /* Partial write, not error. */
268 free(random_buf, M_ENTROPY);
274 randomdev_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
277 if (events & (POLLIN | POLLRDNORM)) {
278 if (p_random_alg_context->ra_seeded())
279 events &= (POLLIN | POLLRDNORM);
281 selrecord(td, &rsel);
286 /* This will be called by the entropy processor when it seeds itself and becomes secure */
288 randomdev_unblock(void)
291 selwakeuppri(&rsel, PUSER);
292 wakeup(&random_alg_context);
293 printf("random: unblocking device.\n");
294 /* Do random(9) a favour while we are about it. */
295 (void)atomic_cmpset_int(&arc4rand_iniseed_state, ARC4_ENTR_NONE, ARC4_ENTR_HAVE);
300 randomdev_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr __unused,
301 int flags __unused, struct thread *td __unused)
306 /* Really handled in upper layer */
318 random_source_register(struct random_source *rsource)
320 struct random_sources *rrs;
322 KASSERT(rsource != NULL, ("invalid input to %s", __func__));
324 rrs = malloc(sizeof(*rrs), M_ENTROPY, M_WAITOK);
325 rrs->rrs_source = rsource;
327 printf("random: registering fast source %s\n", rsource->rs_ident);
328 LIST_INSERT_HEAD(&source_list, rrs, rrs_entries);
332 random_source_deregister(struct random_source *rsource)
334 struct random_sources *rrs = NULL;
336 KASSERT(rsource != NULL, ("invalid input to %s", __func__));
337 LIST_FOREACH(rrs, &source_list, rrs_entries)
338 if (rrs->rrs_source == rsource) {
339 LIST_REMOVE(rrs, rrs_entries);
343 free(rrs, M_ENTROPY);
347 random_source_handler(SYSCTL_HANDLER_ARGS)
349 struct random_sources *rrs;
353 sbuf_new_for_sysctl(&sbuf, NULL, 64, req);
355 LIST_FOREACH(rrs, &source_list, rrs_entries) {
356 sbuf_cat(&sbuf, (count++ ? ",'" : "'"));
357 sbuf_cat(&sbuf, rrs->rrs_source->rs_ident);
358 sbuf_cat(&sbuf, "'");
360 error = sbuf_finish(&sbuf);
364 SYSCTL_PROC(_kern_random, OID_AUTO, random_sources, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
365 NULL, 0, random_source_handler, "A",
366 "List of active fast entropy sources.");
370 randomdev_modevent(module_t mod __unused, int type, void *data __unused)
376 printf("random: entropy device external interface\n");
377 random_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD, &random_cdevsw,
378 RANDOM_UNIT, NULL, UID_ROOT, GID_WHEEL, 0644, "random");
379 make_dev_alias(random_dev, "urandom"); /* compatibility */
382 destroy_dev(random_dev);
393 static moduledata_t randomdev_mod = {
399 DECLARE_MODULE(random_device, randomdev_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
400 MODULE_VERSION(random_device, 1);
401 MODULE_DEPEND(random_device, crypto, 1, 1, 1);
402 MODULE_DEPEND(random_device, random_harvestq, 1, 1, 1);