2 * Copyright (c) 2017 Oliver Pinter
3 * Copyright (c) 2017 W. Dean Freeman
4 * Copyright (c) 2000-2015 Mark R V Murray
5 * Copyright (c) 2013 Arthur Mesh
6 * Copyright (c) 2004 Robert N. M. Watson
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer
14 * in this position and unchanged.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <sys/systm.h>
38 #include <sys/eventhandler.h>
40 #include <sys/kernel.h>
41 #include <sys/kthread.h>
42 #include <sys/linker.h>
44 #include <sys/malloc.h>
45 #include <sys/module.h>
46 #include <sys/mutex.h>
47 #include <sys/random.h>
49 #include <sys/sysctl.h>
50 #include <sys/unistd.h>
52 #if defined(RANDOM_LOADABLE)
57 #include <machine/atomic.h>
58 #include <machine/cpu.h>
60 #include <crypto/rijndael/rijndael-api-fst.h>
61 #include <crypto/sha2/sha256.h>
63 #include <dev/random/hash.h>
64 #include <dev/random/randomdev.h>
65 #include <dev/random/random_harvestq.h>
67 #if defined(RANDOM_ENABLE_ETHER)
68 #define _RANDOM_HARVEST_ETHER_OFF 0
70 #define _RANDOM_HARVEST_ETHER_OFF (1u << RANDOM_NET_ETHER)
72 #if defined(RANDOM_ENABLE_UMA)
73 #define _RANDOM_HARVEST_UMA_OFF 0
75 #define _RANDOM_HARVEST_UMA_OFF (1u << RANDOM_UMA)
78 static void random_kthread(void);
79 static void random_sources_feed(void);
81 static u_int read_rate;
83 /* List for the dynamic sysctls */
84 static struct sysctl_ctx_list random_clist;
87 * How many events to queue up. We create this many items in
88 * an 'empty' queue, then transfer them to the 'harvest' queue with
89 * supplied junk. When used, they are transferred back to the
92 #define RANDOM_RING_MAX 1024
93 #define RANDOM_ACCUM_MAX 8
95 /* 1 to let the kernel thread run, 0 to terminate, -1 to mark completion */
96 volatile int random_kthread_control;
99 /* Allow the sysadmin to select the broad category of
100 * entropy types to harvest.
102 __read_frequently u_int hc_source_mask;
105 * Put all the harvest queue context stuff in one place.
106 * this make is a bit easier to lock and protect.
108 static struct harvest_context {
109 /* The harvest mutex protects all of harvest_context and
113 /* Round-robin destination cache. */
114 u_int hc_destination[ENTROPYSOURCE];
115 /* The context of the kernel thread processing harvested entropy */
116 struct proc *hc_kthread_proc;
118 * Lockless ring buffer holding entropy events
119 * If ring.in == ring.out,
120 * the buffer is empty.
121 * If ring.in != ring.out,
122 * the buffer contains harvested entropy.
123 * If (ring.in + 1) == ring.out (mod RANDOM_RING_MAX),
124 * the buffer is full.
126 * NOTE: ring.in points to the last added element,
127 * and ring.out points to the last consumed element.
129 * The ring.in variable needs locking as there are multiple
130 * sources to the ring. Only the sources may change ring.in,
131 * but the consumer may examine it.
133 * The ring.out variable does not need locking as there is
134 * only one consumer. Only the consumer may change ring.out,
135 * but the sources may examine it.
137 struct entropy_ring {
138 struct harvest_event ring[RANDOM_RING_MAX];
142 struct fast_entropy_accumulator {
144 uint32_t buf[RANDOM_ACCUM_MAX];
145 } hc_entropy_fast_accumulator;
148 static struct kproc_desc random_proc_kp = {
151 &harvest_context.hc_kthread_proc,
154 /* Pass the given event straight through to Fortuna/Whatever. */
156 random_harvestq_fast_process_event(struct harvest_event *event)
158 #if defined(RANDOM_LOADABLE)
159 RANDOM_CONFIG_S_LOCK();
160 if (p_random_alg_context)
162 p_random_alg_context->ra_event_processor(event);
163 #if defined(RANDOM_LOADABLE)
164 RANDOM_CONFIG_S_UNLOCK();
171 u_int maxloop, ring_out, i;
174 * Locking is not needed as this is the only place we modify ring.out, and
175 * we only examine ring.in without changing it. Both of these are volatile,
176 * and this is a unique thread.
178 for (random_kthread_control = 1; random_kthread_control;) {
179 /* Deal with events, if any. Restrict the number we do in one go. */
180 maxloop = RANDOM_RING_MAX;
181 while (harvest_context.hc_entropy_ring.out != harvest_context.hc_entropy_ring.in) {
182 ring_out = (harvest_context.hc_entropy_ring.out + 1)%RANDOM_RING_MAX;
183 random_harvestq_fast_process_event(harvest_context.hc_entropy_ring.ring + ring_out);
184 harvest_context.hc_entropy_ring.out = ring_out;
188 random_sources_feed();
189 /* XXX: FIX!! Increase the high-performance data rate? Need some measurements first. */
190 for (i = 0; i < RANDOM_ACCUM_MAX; i++) {
191 if (harvest_context.hc_entropy_fast_accumulator.buf[i]) {
192 random_harvest_direct(harvest_context.hc_entropy_fast_accumulator.buf + i, sizeof(harvest_context.hc_entropy_fast_accumulator.buf[0]), RANDOM_UMA);
193 harvest_context.hc_entropy_fast_accumulator.buf[i] = 0;
196 /* XXX: FIX!! This is a *great* place to pass hardware/live entropy to random(9) */
197 tsleep_sbt(&harvest_context.hc_kthread_proc, 0, "-", SBT_1S/10, 0, C_PREL(1));
199 random_kthread_control = -1;
200 wakeup(&harvest_context.hc_kthread_proc);
204 /* This happens well after SI_SUB_RANDOM */
205 SYSINIT(random_device_h_proc, SI_SUB_KICK_SCHEDULER, SI_ORDER_ANY, kproc_start,
209 * Run through all fast sources reading entropy for the given
210 * number of rounds, which should be a multiple of the number
211 * of entropy accumulation pools in use; it is 32 for Fortuna.
214 random_sources_feed(void)
216 uint32_t entropy[HARVESTSIZE];
217 struct random_sources *rrs;
218 u_int i, n, local_read_rate;
221 * Step over all of live entropy sources, and feed their output
222 * to the system-wide RNG.
224 #if defined(RANDOM_LOADABLE)
225 RANDOM_CONFIG_S_LOCK();
226 if (p_random_alg_context) {
227 /* It's an indenting error. Yeah, Yeah. */
229 local_read_rate = atomic_readandclear_32(&read_rate);
230 /* Perform at least one read per round */
231 local_read_rate = MAX(local_read_rate, 1);
232 /* But not exceeding RANDOM_KEYSIZE_WORDS */
233 local_read_rate = MIN(local_read_rate, RANDOM_KEYSIZE_WORDS);
234 LIST_FOREACH(rrs, &source_list, rrs_entries) {
235 for (i = 0; i < p_random_alg_context->ra_poolcount*local_read_rate; i++) {
236 n = rrs->rrs_source->rs_read(entropy, sizeof(entropy));
237 KASSERT((n <= sizeof(entropy)), ("%s: rs_read returned too much data (%u > %zu)", __func__, n, sizeof(entropy)));
238 /* It would appear that in some circumstances (e.g. virtualisation),
239 * the underlying hardware entropy source might not always return
240 * random numbers. Accept this but make a noise. If too much happens,
241 * can that source be trusted?
244 printf("%s: rs_read for hardware device '%s' returned no entropy.\n", __func__, rrs->rrs_source->rs_ident);
247 random_harvest_direct(entropy, n, rrs->rrs_source->rs_source);
250 explicit_bzero(entropy, sizeof(entropy));
251 #if defined(RANDOM_LOADABLE)
253 RANDOM_CONFIG_S_UNLOCK();
258 read_rate_increment(u_int chunk)
261 atomic_add_32(&read_rate, chunk);
266 random_check_uint_harvestmask(SYSCTL_HANDLER_ARGS)
268 static const u_int user_immutable_mask =
269 (((1 << ENTROPYSOURCE) - 1) & (-1UL << RANDOM_PURE_START)) |
270 _RANDOM_HARVEST_ETHER_OFF | _RANDOM_HARVEST_UMA_OFF;
273 u_int value, orig_value;
275 orig_value = value = hc_source_mask;
276 error = sysctl_handle_int(oidp, &value, 0, req);
277 if (error != 0 || req->newptr == NULL)
280 if (flsl(value) > ENTROPYSOURCE)
284 * Disallow userspace modification of pure entropy sources.
286 hc_source_mask = (value & ~user_immutable_mask) |
287 (orig_value & user_immutable_mask);
293 random_print_harvestmask(SYSCTL_HANDLER_ARGS)
298 error = sysctl_wire_old_buffer(req, 0);
300 sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
301 for (i = ENTROPYSOURCE - 1; i >= 0; i--)
302 sbuf_cat(&sbuf, (hc_source_mask & (1 << i)) ? "1" : "0");
303 error = sbuf_finish(&sbuf);
309 static const char *random_source_descr[ENTROPYSOURCE] = {
310 [RANDOM_CACHED] = "CACHED",
311 [RANDOM_ATTACH] = "ATTACH",
312 [RANDOM_KEYBOARD] = "KEYBOARD",
313 [RANDOM_MOUSE] = "MOUSE",
314 [RANDOM_NET_TUN] = "NET_TUN",
315 [RANDOM_NET_ETHER] = "NET_ETHER",
316 [RANDOM_NET_NG] = "NET_NG",
317 [RANDOM_INTERRUPT] = "INTERRUPT",
318 [RANDOM_SWI] = "SWI",
319 [RANDOM_FS_ATIME] = "FS_ATIME",
320 [RANDOM_UMA] = "UMA", /* ENVIRONMENTAL_END */
321 [RANDOM_PURE_OCTEON] = "PURE_OCTEON", /* PURE_START */
322 [RANDOM_PURE_SAFE] = "PURE_SAFE",
323 [RANDOM_PURE_GLXSB] = "PURE_GLXSB",
324 [RANDOM_PURE_UBSEC] = "PURE_UBSEC",
325 [RANDOM_PURE_HIFN] = "PURE_HIFN",
326 [RANDOM_PURE_RDRAND] = "PURE_RDRAND",
327 [RANDOM_PURE_NEHEMIAH] = "PURE_NEHEMIAH",
328 [RANDOM_PURE_RNDTEST] = "PURE_RNDTEST",
329 [RANDOM_PURE_VIRTIO] = "PURE_VIRTIO",
330 [RANDOM_PURE_BROADCOM] = "PURE_BROADCOM",
331 [RANDOM_PURE_CCP] = "PURE_CCP",
332 [RANDOM_PURE_DARN] = "PURE_DARN",
333 [RANDOM_PURE_TPM] = "PURE_TPM",
334 /* "ENTROPYSOURCE" */
339 random_print_harvestmask_symbolic(SYSCTL_HANDLER_ARGS)
346 error = sysctl_wire_old_buffer(req, 0);
348 sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
349 for (i = ENTROPYSOURCE - 1; i >= 0; i--) {
350 if (i >= RANDOM_PURE_START &&
351 (hc_source_mask & (1 << i)) == 0)
354 sbuf_cat(&sbuf, ",");
355 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "[" : "");
356 sbuf_cat(&sbuf, random_source_descr[i]);
357 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "]" : "");
360 error = sbuf_finish(&sbuf);
368 random_harvestq_init(void *unused __unused)
370 static const u_int almost_everything_mask =
371 (((1 << (RANDOM_ENVIRONMENTAL_END + 1)) - 1) &
372 ~_RANDOM_HARVEST_ETHER_OFF & ~_RANDOM_HARVEST_UMA_OFF);
374 struct sysctl_oid *random_sys_o;
376 random_sys_o = SYSCTL_ADD_NODE(&random_clist,
377 SYSCTL_STATIC_CHILDREN(_kern_random),
378 OID_AUTO, "harvest", CTLFLAG_RW, 0,
379 "Entropy Device Parameters");
380 hc_source_mask = almost_everything_mask;
381 SYSCTL_ADD_PROC(&random_clist,
382 SYSCTL_CHILDREN(random_sys_o),
383 OID_AUTO, "mask", CTLTYPE_UINT | CTLFLAG_RW,
384 NULL, 0, random_check_uint_harvestmask, "IU",
385 "Entropy harvesting mask");
386 SYSCTL_ADD_PROC(&random_clist,
387 SYSCTL_CHILDREN(random_sys_o),
388 OID_AUTO, "mask_bin", CTLTYPE_STRING | CTLFLAG_RD,
389 NULL, 0, random_print_harvestmask, "A", "Entropy harvesting mask (printable)");
390 SYSCTL_ADD_PROC(&random_clist,
391 SYSCTL_CHILDREN(random_sys_o),
392 OID_AUTO, "mask_symbolic", CTLTYPE_STRING | CTLFLAG_RD,
393 NULL, 0, random_print_harvestmask_symbolic, "A", "Entropy harvesting mask (symbolic)");
394 RANDOM_HARVEST_INIT_LOCK();
395 harvest_context.hc_entropy_ring.in = harvest_context.hc_entropy_ring.out = 0;
397 SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_SECOND, random_harvestq_init, NULL);
400 * This is used to prime the RNG by grabbing any early random stuff
401 * known to the kernel, and inserting it directly into the hashing
402 * module, currently Fortuna.
406 random_harvestq_prime(void *unused __unused)
408 struct harvest_event event;
409 size_t count, size, i;
410 uint8_t *keyfile, *data;
413 * Get entropy that may have been preloaded by loader(8)
414 * and use it to pre-charge the entropy harvest queue.
416 keyfile = preload_search_by_type(RANDOM_CACHED_BOOT_ENTROPY_MODULE);
417 #ifndef NO_BACKWARD_COMPATIBILITY
419 keyfile = preload_search_by_type(RANDOM_LEGACY_BOOT_ENTROPY_MODULE);
421 if (keyfile != NULL) {
422 data = preload_fetch_addr(keyfile);
423 size = preload_fetch_size(keyfile);
424 /* skip the first bit of the stash so others like arc4 can also have some. */
425 if (size > RANDOM_CACHED_SKIP_START) {
426 data += RANDOM_CACHED_SKIP_START;
427 size -= RANDOM_CACHED_SKIP_START;
429 /* Trim the size. If the admin has a file with a funny size, we lose some. Tough. */
430 size -= (size % sizeof(event.he_entropy));
431 if (data != NULL && size != 0) {
432 for (i = 0; i < size; i += sizeof(event.he_entropy)) {
433 count = sizeof(event.he_entropy);
434 event.he_somecounter = (uint32_t)get_cyclecount();
435 event.he_size = count;
436 event.he_source = RANDOM_CACHED;
437 event.he_destination =
438 harvest_context.hc_destination[RANDOM_CACHED]++;
439 memcpy(event.he_entropy, data + i, sizeof(event.he_entropy));
440 random_harvestq_fast_process_event(&event);
441 explicit_bzero(&event, sizeof(event));
443 explicit_bzero(data, size);
445 printf("random: read %zu bytes from preloaded cache\n", size);
448 printf("random: no preloaded entropy cache\n");
451 SYSINIT(random_device_prime, SI_SUB_RANDOM, SI_ORDER_FOURTH, random_harvestq_prime, NULL);
455 random_harvestq_deinit(void *unused __unused)
458 /* Command the hash/reseed thread to end and wait for it to finish */
459 random_kthread_control = 0;
460 while (random_kthread_control >= 0)
461 tsleep(&harvest_context.hc_kthread_proc, 0, "harvqterm", hz/5);
462 sysctl_ctx_free(&random_clist);
464 SYSUNINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_SECOND, random_harvestq_deinit, NULL);
467 * Entropy harvesting queue routine.
469 * This is supposed to be fast; do not do anything slow in here!
470 * It is also illegal (and morally reprehensible) to insert any
471 * high-rate data here. "High-rate" is defined as a data source
472 * that will usually cause lots of failures of the "Lockless read"
473 * check a few lines below. This includes the "always-on" sources
474 * like the Intel "rdrand" or the VIA Nehamiah "xstore" sources.
476 /* XXXRW: get_cyclecount() is cheap on most modern hardware, where cycle
477 * counters are built in, but on older hardware it will do a real time clock
478 * read which can be quite expensive.
481 random_harvest_queue_(const void *entropy, u_int size, enum random_entropy_source origin)
483 struct harvest_event *event;
486 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin));
487 RANDOM_HARVEST_LOCK();
488 ring_in = (harvest_context.hc_entropy_ring.in + 1)%RANDOM_RING_MAX;
489 if (ring_in != harvest_context.hc_entropy_ring.out) {
490 /* The ring is not full */
491 event = harvest_context.hc_entropy_ring.ring + ring_in;
492 event->he_somecounter = (uint32_t)get_cyclecount();
493 event->he_source = origin;
494 event->he_destination = harvest_context.hc_destination[origin]++;
495 if (size <= sizeof(event->he_entropy)) {
496 event->he_size = size;
497 memcpy(event->he_entropy, entropy, size);
500 /* Big event, so squash it */
501 event->he_size = sizeof(event->he_entropy[0]);
502 event->he_entropy[0] = jenkins_hash(entropy, size, (uint32_t)(uintptr_t)event);
504 harvest_context.hc_entropy_ring.in = ring_in;
506 RANDOM_HARVEST_UNLOCK();
510 * Entropy harvesting fast routine.
512 * This is supposed to be very fast; do not do anything slow in here!
513 * This is the right place for high-rate harvested data.
516 random_harvest_fast_(const void *entropy, u_int size)
520 pos = harvest_context.hc_entropy_fast_accumulator.pos;
521 harvest_context.hc_entropy_fast_accumulator.buf[pos] ^= jenkins_hash(entropy, size, (uint32_t)get_cyclecount());
522 harvest_context.hc_entropy_fast_accumulator.pos = (pos + 1)%RANDOM_ACCUM_MAX;
526 * Entropy harvesting direct routine.
528 * This is not supposed to be fast, but will only be used during
529 * (e.g.) booting when initial entropy is being gathered.
532 random_harvest_direct_(const void *entropy, u_int size, enum random_entropy_source origin)
534 struct harvest_event event;
536 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin));
537 size = MIN(size, sizeof(event.he_entropy));
538 event.he_somecounter = (uint32_t)get_cyclecount();
539 event.he_size = size;
540 event.he_source = origin;
541 event.he_destination = harvest_context.hc_destination[origin]++;
542 memcpy(event.he_entropy, entropy, size);
543 random_harvestq_fast_process_event(&event);
544 explicit_bzero(&event, sizeof(event));
548 random_harvest_register_source(enum random_entropy_source source)
551 hc_source_mask |= (1 << source);
555 random_harvest_deregister_source(enum random_entropy_source source)
558 hc_source_mask &= ~(1 << source);
561 MODULE_VERSION(random_harvestq, 1);