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 static void random_kthread(void);
68 static void random_sources_feed(void);
70 static u_int read_rate;
72 /* List for the dynamic sysctls */
73 static struct sysctl_ctx_list random_clist;
76 * How many events to queue up. We create this many items in
77 * an 'empty' queue, then transfer them to the 'harvest' queue with
78 * supplied junk. When used, they are transferred back to the
81 #define RANDOM_RING_MAX 1024
82 #define RANDOM_ACCUM_MAX 8
84 /* 1 to let the kernel thread run, 0 to terminate, -1 to mark completion */
85 volatile int random_kthread_control;
88 /* Allow the sysadmin to select the broad category of
89 * entropy types to harvest.
91 __read_frequently u_int hc_source_mask;
94 * Put all the harvest queue context stuff in one place.
95 * this make is a bit easier to lock and protect.
97 static struct harvest_context {
98 /* The harvest mutex protects all of harvest_context and
102 /* Round-robin destination cache. */
103 u_int hc_destination[ENTROPYSOURCE];
104 /* The context of the kernel thread processing harvested entropy */
105 struct proc *hc_kthread_proc;
107 * Lockless ring buffer holding entropy events
108 * If ring.in == ring.out,
109 * the buffer is empty.
110 * If ring.in != ring.out,
111 * the buffer contains harvested entropy.
112 * If (ring.in + 1) == ring.out (mod RANDOM_RING_MAX),
113 * the buffer is full.
115 * NOTE: ring.in points to the last added element,
116 * and ring.out points to the last consumed element.
118 * The ring.in variable needs locking as there are multiple
119 * sources to the ring. Only the sources may change ring.in,
120 * but the consumer may examine it.
122 * The ring.out variable does not need locking as there is
123 * only one consumer. Only the consumer may change ring.out,
124 * but the sources may examine it.
126 struct entropy_ring {
127 struct harvest_event ring[RANDOM_RING_MAX];
131 struct fast_entropy_accumulator {
133 uint32_t buf[RANDOM_ACCUM_MAX];
134 } hc_entropy_fast_accumulator;
137 static struct kproc_desc random_proc_kp = {
140 &harvest_context.hc_kthread_proc,
143 /* Pass the given event straight through to Fortuna/Whatever. */
145 random_harvestq_fast_process_event(struct harvest_event *event)
147 #if defined(RANDOM_LOADABLE)
148 RANDOM_CONFIG_S_LOCK();
149 if (p_random_alg_context)
151 p_random_alg_context->ra_event_processor(event);
152 #if defined(RANDOM_LOADABLE)
153 RANDOM_CONFIG_S_UNLOCK();
160 u_int maxloop, ring_out, i;
163 * Locking is not needed as this is the only place we modify ring.out, and
164 * we only examine ring.in without changing it. Both of these are volatile,
165 * and this is a unique thread.
167 for (random_kthread_control = 1; random_kthread_control;) {
168 /* Deal with events, if any. Restrict the number we do in one go. */
169 maxloop = RANDOM_RING_MAX;
170 while (harvest_context.hc_entropy_ring.out != harvest_context.hc_entropy_ring.in) {
171 ring_out = (harvest_context.hc_entropy_ring.out + 1)%RANDOM_RING_MAX;
172 random_harvestq_fast_process_event(harvest_context.hc_entropy_ring.ring + ring_out);
173 harvest_context.hc_entropy_ring.out = ring_out;
177 random_sources_feed();
178 /* XXX: FIX!! Increase the high-performance data rate? Need some measurements first. */
179 for (i = 0; i < RANDOM_ACCUM_MAX; i++) {
180 if (harvest_context.hc_entropy_fast_accumulator.buf[i]) {
181 random_harvest_direct(harvest_context.hc_entropy_fast_accumulator.buf + i, sizeof(harvest_context.hc_entropy_fast_accumulator.buf[0]), RANDOM_UMA);
182 harvest_context.hc_entropy_fast_accumulator.buf[i] = 0;
185 /* XXX: FIX!! This is a *great* place to pass hardware/live entropy to random(9) */
186 tsleep_sbt(&harvest_context.hc_kthread_proc, 0, "-", SBT_1S/10, 0, C_PREL(1));
188 random_kthread_control = -1;
189 wakeup(&harvest_context.hc_kthread_proc);
193 /* This happens well after SI_SUB_RANDOM */
194 SYSINIT(random_device_h_proc, SI_SUB_KICK_SCHEDULER, SI_ORDER_ANY, kproc_start,
198 * Run through all fast sources reading entropy for the given
199 * number of rounds, which should be a multiple of the number
200 * of entropy accumulation pools in use; it is 32 for Fortuna.
203 random_sources_feed(void)
205 uint32_t entropy[HARVESTSIZE];
206 struct random_sources *rrs;
207 u_int i, n, local_read_rate;
210 * Step over all of live entropy sources, and feed their output
211 * to the system-wide RNG.
213 #if defined(RANDOM_LOADABLE)
214 RANDOM_CONFIG_S_LOCK();
215 if (p_random_alg_context) {
216 /* It's an indenting error. Yeah, Yeah. */
218 local_read_rate = atomic_readandclear_32(&read_rate);
219 /* Perform at least one read per round */
220 local_read_rate = MAX(local_read_rate, 1);
221 /* But not exceeding RANDOM_KEYSIZE_WORDS */
222 local_read_rate = MIN(local_read_rate, RANDOM_KEYSIZE_WORDS);
223 LIST_FOREACH(rrs, &source_list, rrs_entries) {
224 for (i = 0; i < p_random_alg_context->ra_poolcount*local_read_rate; i++) {
225 n = rrs->rrs_source->rs_read(entropy, sizeof(entropy));
226 KASSERT((n <= sizeof(entropy)), ("%s: rs_read returned too much data (%u > %zu)", __func__, n, sizeof(entropy)));
227 /* It would appear that in some circumstances (e.g. virtualisation),
228 * the underlying hardware entropy source might not always return
229 * random numbers. Accept this but make a noise. If too much happens,
230 * can that source be trusted?
233 printf("%s: rs_read for hardware device '%s' returned no entropy.\n", __func__, rrs->rrs_source->rs_ident);
236 random_harvest_direct(entropy, n, rrs->rrs_source->rs_source);
239 explicit_bzero(entropy, sizeof(entropy));
240 #if defined(RANDOM_LOADABLE)
242 RANDOM_CONFIG_S_UNLOCK();
247 read_rate_increment(u_int chunk)
250 atomic_add_32(&read_rate, chunk);
255 random_check_uint_harvestmask(SYSCTL_HANDLER_ARGS)
258 u_int value, orig_value;
260 orig_value = value = hc_source_mask;
261 error = sysctl_handle_int(oidp, &value, 0, req);
262 if (error != 0 || req->newptr == NULL)
265 if (flsl(value) > ENTROPYSOURCE)
269 * Disallow userspace modification of pure entropy sources.
271 hc_source_mask = (value & ~RANDOM_HARVEST_PURE_MASK) |
272 (orig_value & RANDOM_HARVEST_PURE_MASK);
278 random_print_harvestmask(SYSCTL_HANDLER_ARGS)
283 error = sysctl_wire_old_buffer(req, 0);
285 sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
286 for (i = ENTROPYSOURCE - 1; i >= 0; i--)
287 sbuf_cat(&sbuf, (hc_source_mask & (1 << i)) ? "1" : "0");
288 error = sbuf_finish(&sbuf);
294 static const char *random_source_descr[ENTROPYSOURCE] = {
295 [RANDOM_CACHED] = "CACHED",
296 [RANDOM_ATTACH] = "ATTACH",
297 [RANDOM_KEYBOARD] = "KEYBOARD",
298 [RANDOM_MOUSE] = "MOUSE",
299 [RANDOM_NET_TUN] = "NET_TUN",
300 [RANDOM_NET_ETHER] = "NET_ETHER",
301 [RANDOM_NET_NG] = "NET_NG",
302 [RANDOM_INTERRUPT] = "INTERRUPT",
303 [RANDOM_SWI] = "SWI",
304 [RANDOM_FS_ATIME] = "FS_ATIME",
305 [RANDOM_UMA] = "UMA", /* ENVIRONMENTAL_END */
306 [RANDOM_PURE_OCTEON] = "PURE_OCTEON", /* PURE_START */
307 [RANDOM_PURE_SAFE] = "PURE_SAFE",
308 [RANDOM_PURE_GLXSB] = "PURE_GLXSB",
309 [RANDOM_PURE_UBSEC] = "PURE_UBSEC",
310 [RANDOM_PURE_HIFN] = "PURE_HIFN",
311 [RANDOM_PURE_RDRAND] = "PURE_RDRAND",
312 [RANDOM_PURE_NEHEMIAH] = "PURE_NEHEMIAH",
313 [RANDOM_PURE_RNDTEST] = "PURE_RNDTEST",
314 [RANDOM_PURE_VIRTIO] = "PURE_VIRTIO",
315 [RANDOM_PURE_BROADCOM] = "PURE_BROADCOM",
316 [RANDOM_PURE_CCP] = "PURE_CCP",
317 [RANDOM_PURE_DARN] = "PURE_DARN",
318 /* "ENTROPYSOURCE" */
323 random_print_harvestmask_symbolic(SYSCTL_HANDLER_ARGS)
330 error = sysctl_wire_old_buffer(req, 0);
332 sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
333 for (i = ENTROPYSOURCE - 1; i >= 0; i--) {
334 if (i >= RANDOM_PURE_START &&
335 (hc_source_mask & (1 << i)) == 0)
338 sbuf_cat(&sbuf, ",");
339 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "[" : "");
340 sbuf_cat(&sbuf, random_source_descr[i]);
341 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "]" : "");
344 error = sbuf_finish(&sbuf);
352 random_harvestq_init(void *unused __unused)
354 struct sysctl_oid *random_sys_o;
356 random_sys_o = SYSCTL_ADD_NODE(&random_clist,
357 SYSCTL_STATIC_CHILDREN(_kern_random),
358 OID_AUTO, "harvest", CTLFLAG_RW, 0,
359 "Entropy Device Parameters");
360 hc_source_mask = RANDOM_HARVEST_EVERYTHING_MASK;
361 SYSCTL_ADD_PROC(&random_clist,
362 SYSCTL_CHILDREN(random_sys_o),
363 OID_AUTO, "mask", CTLTYPE_UINT | CTLFLAG_RW,
364 NULL, 0, random_check_uint_harvestmask, "IU",
365 "Entropy harvesting mask");
366 SYSCTL_ADD_PROC(&random_clist,
367 SYSCTL_CHILDREN(random_sys_o),
368 OID_AUTO, "mask_bin", CTLTYPE_STRING | CTLFLAG_RD,
369 NULL, 0, random_print_harvestmask, "A", "Entropy harvesting mask (printable)");
370 SYSCTL_ADD_PROC(&random_clist,
371 SYSCTL_CHILDREN(random_sys_o),
372 OID_AUTO, "mask_symbolic", CTLTYPE_STRING | CTLFLAG_RD,
373 NULL, 0, random_print_harvestmask_symbolic, "A", "Entropy harvesting mask (symbolic)");
374 RANDOM_HARVEST_INIT_LOCK();
375 harvest_context.hc_entropy_ring.in = harvest_context.hc_entropy_ring.out = 0;
377 SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_SECOND, random_harvestq_init, NULL);
380 * This is used to prime the RNG by grabbing any early random stuff
381 * known to the kernel, and inserting it directly into the hashing
382 * module, currently Fortuna.
386 random_harvestq_prime(void *unused __unused)
388 struct harvest_event event;
389 size_t count, size, i;
390 uint8_t *keyfile, *data;
393 * Get entropy that may have been preloaded by loader(8)
394 * and use it to pre-charge the entropy harvest queue.
396 keyfile = preload_search_by_type(RANDOM_CACHED_BOOT_ENTROPY_MODULE);
397 #ifndef NO_BACKWARD_COMPATIBILITY
399 keyfile = preload_search_by_type(RANDOM_LEGACY_BOOT_ENTROPY_MODULE);
401 if (keyfile != NULL) {
402 data = preload_fetch_addr(keyfile);
403 size = preload_fetch_size(keyfile);
404 /* skip the first bit of the stash so others like arc4 can also have some. */
405 if (size > RANDOM_CACHED_SKIP_START) {
406 data += RANDOM_CACHED_SKIP_START;
407 size -= RANDOM_CACHED_SKIP_START;
409 /* Trim the size. If the admin has a file with a funny size, we lose some. Tough. */
410 size -= (size % sizeof(event.he_entropy));
411 if (data != NULL && size != 0) {
412 for (i = 0; i < size; i += sizeof(event.he_entropy)) {
413 count = sizeof(event.he_entropy);
414 event.he_somecounter = (uint32_t)get_cyclecount();
415 event.he_size = count;
416 event.he_source = RANDOM_CACHED;
417 event.he_destination = harvest_context.hc_destination[0]++;
418 memcpy(event.he_entropy, data + i, sizeof(event.he_entropy));
419 random_harvestq_fast_process_event(&event);
420 explicit_bzero(&event, sizeof(event));
422 explicit_bzero(data, size);
424 printf("random: read %zu bytes from preloaded cache\n", size);
427 printf("random: no preloaded entropy cache\n");
430 SYSINIT(random_device_prime, SI_SUB_RANDOM, SI_ORDER_FOURTH, random_harvestq_prime, NULL);
434 random_harvestq_deinit(void *unused __unused)
437 /* Command the hash/reseed thread to end and wait for it to finish */
438 random_kthread_control = 0;
439 while (random_kthread_control >= 0)
440 tsleep(&harvest_context.hc_kthread_proc, 0, "harvqterm", hz/5);
441 sysctl_ctx_free(&random_clist);
443 SYSUNINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_SECOND, random_harvestq_deinit, NULL);
446 * Entropy harvesting queue routine.
448 * This is supposed to be fast; do not do anything slow in here!
449 * It is also illegal (and morally reprehensible) to insert any
450 * high-rate data here. "High-rate" is defined as a data source
451 * that will usually cause lots of failures of the "Lockless read"
452 * check a few lines below. This includes the "always-on" sources
453 * like the Intel "rdrand" or the VIA Nehamiah "xstore" sources.
455 /* XXXRW: get_cyclecount() is cheap on most modern hardware, where cycle
456 * counters are built in, but on older hardware it will do a real time clock
457 * read which can be quite expensive.
460 random_harvest_queue_(const void *entropy, u_int size, enum random_entropy_source origin)
462 struct harvest_event *event;
465 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin));
466 RANDOM_HARVEST_LOCK();
467 ring_in = (harvest_context.hc_entropy_ring.in + 1)%RANDOM_RING_MAX;
468 if (ring_in != harvest_context.hc_entropy_ring.out) {
469 /* The ring is not full */
470 event = harvest_context.hc_entropy_ring.ring + ring_in;
471 event->he_somecounter = (uint32_t)get_cyclecount();
472 event->he_source = origin;
473 event->he_destination = harvest_context.hc_destination[origin]++;
474 if (size <= sizeof(event->he_entropy)) {
475 event->he_size = size;
476 memcpy(event->he_entropy, entropy, size);
479 /* Big event, so squash it */
480 event->he_size = sizeof(event->he_entropy[0]);
481 event->he_entropy[0] = jenkins_hash(entropy, size, (uint32_t)(uintptr_t)event);
483 harvest_context.hc_entropy_ring.in = ring_in;
485 RANDOM_HARVEST_UNLOCK();
489 * Entropy harvesting fast routine.
491 * This is supposed to be very fast; do not do anything slow in here!
492 * This is the right place for high-rate harvested data.
495 random_harvest_fast_(const void *entropy, u_int size)
499 pos = harvest_context.hc_entropy_fast_accumulator.pos;
500 harvest_context.hc_entropy_fast_accumulator.buf[pos] ^= jenkins_hash(entropy, size, (uint32_t)get_cyclecount());
501 harvest_context.hc_entropy_fast_accumulator.pos = (pos + 1)%RANDOM_ACCUM_MAX;
505 * Entropy harvesting direct routine.
507 * This is not supposed to be fast, but will only be used during
508 * (e.g.) booting when initial entropy is being gathered.
511 random_harvest_direct_(const void *entropy, u_int size, enum random_entropy_source origin)
513 struct harvest_event event;
515 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin));
516 size = MIN(size, sizeof(event.he_entropy));
517 event.he_somecounter = (uint32_t)get_cyclecount();
518 event.he_size = size;
519 event.he_source = origin;
520 event.he_destination = harvest_context.hc_destination[origin]++;
521 memcpy(event.he_entropy, entropy, size);
522 random_harvestq_fast_process_event(&event);
523 explicit_bzero(&event, sizeof(event));
527 random_harvest_register_source(enum random_entropy_source source)
530 hc_source_mask |= (1 << source);
534 random_harvest_deregister_source(enum random_entropy_source source)
537 hc_source_mask &= ~(1 << source);
540 MODULE_VERSION(random_harvestq, 1);