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/sha2.h>
55 #include <dev/random/hash.h>
56 #include <dev/random/randomdev.h>
57 #include <dev/random/random_harvestq.h>
59 #include "opt_random.h"
61 #if defined(RANDOM_DUMMY) && defined(RANDOM_YARROW)
62 #error "Cannot define both RANDOM_DUMMY and RANDOM_YARROW"
65 #define RANDOM_MINOR 0
67 static d_read_t randomdev_read;
68 static d_write_t randomdev_write;
69 static d_poll_t randomdev_poll;
70 static d_ioctl_t randomdev_ioctl;
72 static struct cdevsw random_cdevsw = {
74 .d_version = D_VERSION,
75 .d_read = randomdev_read,
76 .d_write = randomdev_write,
77 .d_poll = randomdev_poll,
78 .d_ioctl = randomdev_ioctl,
81 /* For use with make_dev(9)/destroy_dev(9). */
82 static struct cdev *random_dev;
84 /* Set up the sysctl root node for the entropy device */
85 SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW, 0, "Cryptographically Secure Random Number Generator");
87 MALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers and data structures");
89 #if defined(RANDOM_DUMMY)
92 * Dummy "always block" pseudo algorithm, used when there is no real
93 * random(4) driver to provide a CSPRNG.
97 dummy_random_zero(void)
108 struct random_algorithm random_alg_context = {
110 .ra_reseed = dummy_random,
111 .ra_seeded = (random_alg_seeded_t *)dummy_random_zero,
112 .ra_pre_read = dummy_random,
113 .ra_read = (random_alg_read_t *)dummy_random_zero,
114 .ra_post_read = dummy_random,
115 .ra_write = (random_alg_write_t *)dummy_random_zero,
116 .ra_event_processor = NULL,
120 #else /* !defined(RANDOM_DUMMY) */
122 LIST_HEAD(sources_head, random_sources);
123 static struct sources_head source_list = LIST_HEAD_INITIALIZER(source_list);
124 static u_int read_rate;
126 #endif /* defined(RANDOM_DUMMY) */
128 static struct selinfo rsel;
131 * This is the read uio(9) interface for random(4).
135 randomdev_read(struct cdev *dev __unused, struct uio *uio, int flags)
141 random_buf = malloc(PAGE_SIZE, M_ENTROPY, M_WAITOK);
142 random_alg_context.ra_pre_read();
143 /* (Un)Blocking logic */
145 while (!random_alg_context.ra_seeded() && error == 0) {
146 if (flags & O_NONBLOCK) {
150 tsleep(&random_alg_context, 0, "randrd", hz/10);
151 /* keep tapping away at the pre-read until we seed/unblock. */
152 random_alg_context.ra_pre_read();
153 printf("random: %s unblock (error = %d)\n", __func__, error);
156 #if !defined(RANDOM_DUMMY)
157 /* XXX: FIX!! Next line as an atomic operation? */
158 read_rate += (uio->uio_resid + sizeof(uint32_t))/sizeof(uint32_t);
160 nbytes = uio->uio_resid;
161 while (uio->uio_resid && !error) {
162 c = MIN(uio->uio_resid, PAGE_SIZE);
163 random_alg_context.ra_read(random_buf, c);
164 error = uiomove(random_buf, c, uio);
166 random_alg_context.ra_post_read();
167 if (nbytes != uio->uio_resid && (error == ERESTART || error == EINTR) )
168 /* Return partial read, not error. */
171 free(random_buf, M_ENTROPY);
176 * Kernel API version of read_random().
177 * This is similar to random_alg_read(),
178 * except it doesn't interface with uio(9).
179 * It cannot assumed that random_buf is a multiple of
180 * RANDOM_BLOCKSIZE bytes.
183 read_random(void *random_buf, u_int len)
185 u_int read_len, total_read, c;
186 uint8_t local_buf[len + RANDOM_BLOCKSIZE];
188 KASSERT(random_buf != NULL, ("No suitable random buffer in %s", __func__));
189 random_alg_context.ra_pre_read();
190 /* (Un)Blocking logic; if not seeded, return nothing. */
191 if (random_alg_context.ra_seeded()) {
192 #if !defined(RANDOM_DUMMY)
193 /* XXX: FIX!! Next line as an atomic operation? */
194 read_rate += (len + sizeof(uint32_t))/sizeof(uint32_t);
199 c = MIN(read_len, PAGE_SIZE);
200 random_alg_context.ra_read(&local_buf[total_read], c);
204 memcpy(random_buf, local_buf, len);
207 random_alg_context.ra_post_read();
213 randomdev_write(struct cdev *dev __unused, struct uio *uio, int flags __unused)
219 random_buf = malloc(PAGE_SIZE, M_ENTROPY, M_WAITOK);
220 nbytes = uio->uio_resid;
221 while (uio->uio_resid > 0 && error == 0) {
222 c = MIN(uio->uio_resid, PAGE_SIZE);
223 error = uiomove(random_buf, c, uio);
226 random_alg_context.ra_write(random_buf, c);
227 tsleep(&random_alg_context, 0, "randwr", hz/10);
229 if (nbytes != uio->uio_resid && (error == ERESTART || error == EINTR))
230 /* Partial write, not error. */
232 free(random_buf, M_ENTROPY);
238 randomdev_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
241 if (events & (POLLIN | POLLRDNORM)) {
242 if (random_alg_context.ra_seeded())
243 events &= (POLLIN | POLLRDNORM);
245 selrecord(td, &rsel);
250 /* This will be called by the entropy processor when it seeds itself and becomes secure */
252 randomdev_unblock(void)
255 selwakeuppri(&rsel, PUSER);
256 wakeup(&random_alg_context);
257 printf("random: unblocking device.\n");
258 /* Do random(9) a favour while we are about it. */
259 (void)atomic_cmpset_int(&arc4rand_iniseed_state, ARC4_ENTR_NONE, ARC4_ENTR_HAVE);
264 randomdev_ioctl(struct cdev *dev __unused, u_long cmd, caddr_t addr __unused,
265 int flags __unused, struct thread *td __unused)
270 /* Really handled in upper layer */
282 random_source_register(struct random_source *rsource)
284 #if defined(RANDOM_DUMMY)
286 #else /* !defined(RANDOM_DUMMY) */
287 struct random_sources *rrs;
289 KASSERT(rsource != NULL, ("invalid input to %s", __func__));
291 rrs = malloc(sizeof(*rrs), M_ENTROPY, M_WAITOK);
292 rrs->rrs_source = rsource;
294 printf("random: registering fast source %s\n", rsource->rs_ident);
295 LIST_INSERT_HEAD(&source_list, rrs, rrs_entries);
296 #endif /* defined(RANDOM_DUMMY) */
300 random_source_deregister(struct random_source *rsource)
302 #if defined(RANDOM_DUMMY)
304 #else /* !defined(RANDOM_DUMMY) */
305 struct random_sources *rrs = NULL;
307 KASSERT(rsource != NULL, ("invalid input to %s", __func__));
308 LIST_FOREACH(rrs, &source_list, rrs_entries)
309 if (rrs->rrs_source == rsource) {
310 LIST_REMOVE(rrs, rrs_entries);
314 free(rrs, M_ENTROPY);
315 #endif /* defined(RANDOM_DUMMY) */
318 #if !defined(RANDOM_DUMMY)
320 * Run through all fast sources reading entropy for the given
321 * number of rounds, which should be a multiple of the number
322 * of entropy accumulation pools in use; 2 for Yarrow and 32
326 * This function runs inside the RNG thread! Don't do anything silly!
329 random_sources_feed(void)
331 uint32_t entropy[HARVESTSIZE];
332 struct random_sources *rrs;
333 u_int i, n, local_read_rate;
336 * Step over all of live entropy sources, and feed their output
337 * to the system-wide RNG.
339 /* XXX: FIX!! Next lines as an atomic operation? */
340 local_read_rate = read_rate;
341 read_rate = RANDOM_ALG_READ_RATE_MINIMUM;
342 LIST_FOREACH(rrs, &source_list, rrs_entries) {
343 for (i = 0; i < random_alg_context.ra_poolcount*local_read_rate; i++) {
344 n = rrs->rrs_source->rs_read(entropy, sizeof(entropy));
345 KASSERT((n > 0 && n <= sizeof(entropy)), ("very bad return from rs_read (= %d) in %s", n, __func__));
346 random_harvest_direct(entropy, n, (n*8)/2, rrs->rrs_source->rs_source);
349 explicit_bzero(entropy, sizeof(entropy));
353 random_source_handler(SYSCTL_HANDLER_ARGS)
355 struct random_sources *rrs;
359 sbuf_new_for_sysctl(&sbuf, NULL, 64, req);
361 LIST_FOREACH(rrs, &source_list, rrs_entries) {
362 sbuf_cat(&sbuf, (count++ ? ",'" : "'"));
363 sbuf_cat(&sbuf, rrs->rrs_source->rs_ident);
364 sbuf_cat(&sbuf, "'");
366 error = sbuf_finish(&sbuf);
370 SYSCTL_PROC(_kern_random, OID_AUTO, random_sources, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
371 NULL, 0, random_source_handler, "A",
372 "List of active fast entropy sources.");
373 #endif /* !defined(RANDOM_DUMMY) */
377 randomdev_modevent(module_t mod __unused, int type, void *data __unused)
383 printf("random: entropy device external interface\n");
384 random_dev = make_dev_credf(MAKEDEV_ETERNAL_KLD, &random_cdevsw,
385 RANDOM_MINOR, NULL, UID_ROOT, GID_WHEEL, 0644, "random");
386 make_dev_alias(random_dev, "urandom"); /* compatibility */
389 destroy_dev(random_dev);
400 static moduledata_t randomdev_mod = {
406 DECLARE_MODULE(random_device, randomdev_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
407 MODULE_VERSION(random_device, 1);