1 /*-
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
7 * All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
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.
18 *
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.
29 *
30 */
31
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/ck.h>
35 #include <sys/conf.h>
36 #include <sys/epoch.h>
37 #include <sys/eventhandler.h>
38 #include <sys/hash.h>
39 #include <sys/kernel.h>
40 #include <sys/kthread.h>
41 #include <sys/linker.h>
42 #include <sys/lock.h>
43 #include <sys/malloc.h>
44 #include <sys/module.h>
45 #include <sys/mutex.h>
46 #include <sys/random.h>
47 #include <sys/sbuf.h>
48 #include <sys/sysctl.h>
49 #include <sys/unistd.h>
50
51 #include <machine/atomic.h>
52 #include <machine/cpu.h>
53
54 #include <crypto/rijndael/rijndael-api-fst.h>
55 #include <crypto/sha2/sha256.h>
56
57 #include <dev/random/hash.h>
58 #include <dev/random/randomdev.h>
59 #include <dev/random/random_harvestq.h>
60
61 #if defined(RANDOM_ENABLE_ETHER)
62 #define _RANDOM_HARVEST_ETHER_OFF 0
63 #else
64 #define _RANDOM_HARVEST_ETHER_OFF (1u << RANDOM_NET_ETHER)
65 #endif
66 #if defined(RANDOM_ENABLE_UMA)
67 #define _RANDOM_HARVEST_UMA_OFF 0
68 #else
69 #define _RANDOM_HARVEST_UMA_OFF (1u << RANDOM_UMA)
70 #endif
71
72 /*
73 * Note that random_sources_feed() will also use this to try and split up
74 * entropy into a subset of pools per iteration with the goal of feeding
75 * HARVESTSIZE into every pool at least once per second.
76 */
77 #define RANDOM_KTHREAD_HZ 10
78
79 static void random_kthread(void);
80 static void random_sources_feed(void);
81
82 /*
83 * Random must initialize much earlier than epoch, but we can initialize the
84 * epoch code before SMP starts. Prior to SMP, we can safely bypass
85 * concurrency primitives.
86 */
87 static __read_mostly bool epoch_inited;
88 static __read_mostly epoch_t rs_epoch;
89
90 /*
91 * How many events to queue up. We create this many items in
92 * an 'empty' queue, then transfer them to the 'harvest' queue with
93 * supplied junk. When used, they are transferred back to the
94 * 'empty' queue.
95 */
96 #define RANDOM_RING_MAX 1024
97 #define RANDOM_ACCUM_MAX 8
98
99 /* 1 to let the kernel thread run, 0 to terminate, -1 to mark completion */
100 volatile int random_kthread_control;
101
102
103 /* Allow the sysadmin to select the broad category of
104 * entropy types to harvest.
105 */
106 __read_frequently u_int hc_source_mask;
107
108 struct random_sources {
109 CK_LIST_ENTRY(random_sources) rrs_entries;
110 struct random_source *rrs_source;
111 };
112
113 static CK_LIST_HEAD(sources_head, random_sources) source_list =
114 CK_LIST_HEAD_INITIALIZER(source_list);
115
116 SYSCTL_NODE(_kern_random, OID_AUTO, harvest, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
117 "Entropy Device Parameters");
118
119 /*
120 * Put all the harvest queue context stuff in one place.
121 * this make is a bit easier to lock and protect.
122 */
123 static struct harvest_context {
124 /* The harvest mutex protects all of harvest_context and
125 * the related data.
126 */
127 struct mtx hc_mtx;
128 /* Round-robin destination cache. */
129 u_int hc_destination[ENTROPYSOURCE];
130 /* The context of the kernel thread processing harvested entropy */
131 struct proc *hc_kthread_proc;
132 /*
133 * Lockless ring buffer holding entropy events
134 * If ring.in == ring.out,
135 * the buffer is empty.
136 * If ring.in != ring.out,
137 * the buffer contains harvested entropy.
138 * If (ring.in + 1) == ring.out (mod RANDOM_RING_MAX),
139 * the buffer is full.
140 *
141 * NOTE: ring.in points to the last added element,
142 * and ring.out points to the last consumed element.
143 *
144 * The ring.in variable needs locking as there are multiple
145 * sources to the ring. Only the sources may change ring.in,
146 * but the consumer may examine it.
147 *
148 * The ring.out variable does not need locking as there is
149 * only one consumer. Only the consumer may change ring.out,
150 * but the sources may examine it.
151 */
152 struct entropy_ring {
153 struct harvest_event ring[RANDOM_RING_MAX];
154 volatile u_int in;
155 volatile u_int out;
156 } hc_entropy_ring;
157 struct fast_entropy_accumulator {
158 volatile u_int pos;
159 uint32_t buf[RANDOM_ACCUM_MAX];
160 } hc_entropy_fast_accumulator;
161 } harvest_context;
162
163 static struct kproc_desc random_proc_kp = {
164 "rand_harvestq",
165 random_kthread,
166 &harvest_context.hc_kthread_proc,
167 };
168
169 /* Pass the given event straight through to Fortuna/Whatever. */
170 static __inline void
random_harvestq_fast_process_event(struct harvest_event * event)171 random_harvestq_fast_process_event(struct harvest_event *event)
172 {
173 p_random_alg_context->ra_event_processor(event);
174 explicit_bzero(event, sizeof(*event));
175 }
176
177 static void
random_kthread(void)178 random_kthread(void)
179 {
180 u_int maxloop, ring_out, i;
181
182 /*
183 * Locking is not needed as this is the only place we modify ring.out, and
184 * we only examine ring.in without changing it. Both of these are volatile,
185 * and this is a unique thread.
186 */
187 for (random_kthread_control = 1; random_kthread_control;) {
188 /* Deal with events, if any. Restrict the number we do in one go. */
189 maxloop = RANDOM_RING_MAX;
190 while (harvest_context.hc_entropy_ring.out != harvest_context.hc_entropy_ring.in) {
191 ring_out = (harvest_context.hc_entropy_ring.out + 1)%RANDOM_RING_MAX;
192 random_harvestq_fast_process_event(harvest_context.hc_entropy_ring.ring + ring_out);
193 harvest_context.hc_entropy_ring.out = ring_out;
194 if (!--maxloop)
195 break;
196 }
197 random_sources_feed();
198 /* XXX: FIX!! Increase the high-performance data rate? Need some measurements first. */
199 for (i = 0; i < RANDOM_ACCUM_MAX; i++) {
200 if (harvest_context.hc_entropy_fast_accumulator.buf[i]) {
201 random_harvest_direct(harvest_context.hc_entropy_fast_accumulator.buf + i, sizeof(harvest_context.hc_entropy_fast_accumulator.buf[0]), RANDOM_UMA);
202 harvest_context.hc_entropy_fast_accumulator.buf[i] = 0;
203 }
204 }
205 /* XXX: FIX!! This is a *great* place to pass hardware/live entropy to random(9) */
206 tsleep_sbt(&harvest_context.hc_kthread_proc, 0, "-",
207 SBT_1S/RANDOM_KTHREAD_HZ, 0, C_PREL(1));
208 }
209 random_kthread_control = -1;
210 wakeup(&harvest_context.hc_kthread_proc);
211 kproc_exit(0);
212 /* NOTREACHED */
213 }
214 /* This happens well after SI_SUB_RANDOM */
215 SYSINIT(random_device_h_proc, SI_SUB_KICK_SCHEDULER, SI_ORDER_ANY, kproc_start,
216 &random_proc_kp);
217
218 static void
rs_epoch_init(void * dummy __unused)219 rs_epoch_init(void *dummy __unused)
220 {
221 rs_epoch = epoch_alloc("Random Sources", EPOCH_PREEMPT);
222 epoch_inited = true;
223 }
224 SYSINIT(rs_epoch_init, SI_SUB_EPOCH, SI_ORDER_ANY, rs_epoch_init, NULL);
225
226 /*
227 * Run through all fast sources reading entropy for the given
228 * number of rounds, which should be a multiple of the number
229 * of entropy accumulation pools in use; it is 32 for Fortuna.
230 */
231 static void
random_sources_feed(void)232 random_sources_feed(void)
233 {
234 uint32_t entropy[HARVESTSIZE];
235 struct epoch_tracker et;
236 struct random_sources *rrs;
237 u_int i, n, npools;
238 bool rse_warm;
239
240 rse_warm = epoch_inited;
241
242 /*
243 * Evenly-ish distribute pool population across the second based on how
244 * frequently random_kthread iterates.
245 *
246 * For Fortuna, the math currently works out as such:
247 *
248 * 64 bits * 4 pools = 256 bits per iteration
249 * 256 bits * 10 Hz = 2560 bits per second, 320 B/s
250 *
251 */
252 npools = howmany(p_random_alg_context->ra_poolcount, RANDOM_KTHREAD_HZ);
253
254 /*-
255 * If we're not seeded yet, attempt to perform a "full seed", filling
256 * all of the PRNG's pools with entropy; if there is enough entropy
257 * available from "fast" entropy sources this will allow us to finish
258 * seeding and unblock the boot process immediately rather than being
259 * stuck for a few seconds with random_kthread gradually collecting a
260 * small chunk of entropy every 1 / RANDOM_KTHREAD_HZ seconds.
261 *
262 * The value 64 below is RANDOM_FORTUNA_DEFPOOLSIZE, i.e. chosen to
263 * fill Fortuna's pools in the default configuration. With another
264 * PRNG or smaller pools for Fortuna, we might collect more entropy
265 * than needed to fill the pools, but this is harmless; alternatively,
266 * a different PRNG, larger pools, or fast entropy sources which are
267 * not able to provide as much entropy as we request may result in the
268 * not being fully seeded (and thus remaining blocked) but in that
269 * case we will return here after 1 / RANDOM_KTHREAD_HZ seconds and
270 * try again for a large amount of entropy.
271 */
272 if (!p_random_alg_context->ra_seeded())
273 npools = howmany(p_random_alg_context->ra_poolcount * 64,
274 sizeof(entropy));
275
276 /*
277 * Step over all of live entropy sources, and feed their output
278 * to the system-wide RNG.
279 */
280 if (rse_warm)
281 epoch_enter_preempt(rs_epoch, &et);
282 CK_LIST_FOREACH(rrs, &source_list, rrs_entries) {
283 for (i = 0; i < npools; i++) {
284 n = rrs->rrs_source->rs_read(entropy, sizeof(entropy));
285 KASSERT((n <= sizeof(entropy)), ("%s: rs_read returned too much data (%u > %zu)", __func__, n, sizeof(entropy)));
286 /*
287 * Sometimes the HW entropy source doesn't have anything
288 * ready for us. This isn't necessarily untrustworthy.
289 * We don't perform any other verification of an entropy
290 * source (i.e., length is allowed to be anywhere from 1
291 * to sizeof(entropy), quality is unchecked, etc), so
292 * don't balk verbosely at slow random sources either.
293 * There are reports that RDSEED on x86 metal falls
294 * behind the rate at which we query it, for example.
295 * But it's still a better entropy source than RDRAND.
296 */
297 if (n == 0)
298 continue;
299 random_harvest_direct(entropy, n, rrs->rrs_source->rs_source);
300 }
301 }
302 if (rse_warm)
303 epoch_exit_preempt(rs_epoch, &et);
304 explicit_bzero(entropy, sizeof(entropy));
305 }
306
307 /* ARGSUSED */
308 static int
random_check_uint_harvestmask(SYSCTL_HANDLER_ARGS)309 random_check_uint_harvestmask(SYSCTL_HANDLER_ARGS)
310 {
311 static const u_int user_immutable_mask =
312 (((1 << ENTROPYSOURCE) - 1) & (-1UL << RANDOM_PURE_START)) |
313 _RANDOM_HARVEST_ETHER_OFF | _RANDOM_HARVEST_UMA_OFF;
314
315 int error;
316 u_int value, orig_value;
317
318 orig_value = value = hc_source_mask;
319 error = sysctl_handle_int(oidp, &value, 0, req);
320 if (error != 0 || req->newptr == NULL)
321 return (error);
322
323 if (flsl(value) > ENTROPYSOURCE)
324 return (EINVAL);
325
326 /*
327 * Disallow userspace modification of pure entropy sources.
328 */
329 hc_source_mask = (value & ~user_immutable_mask) |
330 (orig_value & user_immutable_mask);
331 return (0);
332 }
333 SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask,
334 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0,
335 random_check_uint_harvestmask, "IU",
336 "Entropy harvesting mask");
337
338 /* ARGSUSED */
339 static int
random_print_harvestmask(SYSCTL_HANDLER_ARGS)340 random_print_harvestmask(SYSCTL_HANDLER_ARGS)
341 {
342 struct sbuf sbuf;
343 int error, i;
344
345 error = sysctl_wire_old_buffer(req, 0);
346 if (error == 0) {
347 sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
348 for (i = ENTROPYSOURCE - 1; i >= 0; i--)
349 sbuf_cat(&sbuf, (hc_source_mask & (1 << i)) ? "1" : "0");
350 error = sbuf_finish(&sbuf);
351 sbuf_delete(&sbuf);
352 }
353 return (error);
354 }
355 SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask_bin,
356 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
357 random_print_harvestmask, "A",
358 "Entropy harvesting mask (printable)");
359
360 static const char *random_source_descr[ENTROPYSOURCE] = {
361 [RANDOM_CACHED] = "CACHED",
362 [RANDOM_ATTACH] = "ATTACH",
363 [RANDOM_KEYBOARD] = "KEYBOARD",
364 [RANDOM_MOUSE] = "MOUSE",
365 [RANDOM_NET_TUN] = "NET_TUN",
366 [RANDOM_NET_ETHER] = "NET_ETHER",
367 [RANDOM_NET_NG] = "NET_NG",
368 [RANDOM_INTERRUPT] = "INTERRUPT",
369 [RANDOM_SWI] = "SWI",
370 [RANDOM_FS_ATIME] = "FS_ATIME",
371 [RANDOM_UMA] = "UMA",
372 [RANDOM_CALLOUT] = "CALLOUT", /* ENVIRONMENTAL_END */
373 [RANDOM_PURE_OCTEON] = "PURE_OCTEON", /* PURE_START */
374 [RANDOM_PURE_SAFE] = "PURE_SAFE",
375 [RANDOM_PURE_GLXSB] = "PURE_GLXSB",
376 [RANDOM_PURE_HIFN] = "PURE_HIFN",
377 [RANDOM_PURE_RDRAND] = "PURE_RDRAND",
378 [RANDOM_PURE_NEHEMIAH] = "PURE_NEHEMIAH",
379 [RANDOM_PURE_RNDTEST] = "PURE_RNDTEST",
380 [RANDOM_PURE_VIRTIO] = "PURE_VIRTIO",
381 [RANDOM_PURE_BROADCOM] = "PURE_BROADCOM",
382 [RANDOM_PURE_CCP] = "PURE_CCP",
383 [RANDOM_PURE_DARN] = "PURE_DARN",
384 [RANDOM_PURE_TPM] = "PURE_TPM",
385 [RANDOM_PURE_VMGENID] = "PURE_VMGENID",
386 [RANDOM_PURE_QUALCOMM] = "PURE_QUALCOMM",
387 [RANDOM_PURE_ARMV8] = "PURE_ARMV8",
388 /* "ENTROPYSOURCE" */
389 };
390
391 /* ARGSUSED */
392 static int
random_print_harvestmask_symbolic(SYSCTL_HANDLER_ARGS)393 random_print_harvestmask_symbolic(SYSCTL_HANDLER_ARGS)
394 {
395 struct sbuf sbuf;
396 int error, i;
397 bool first;
398
399 first = true;
400 error = sysctl_wire_old_buffer(req, 0);
401 if (error == 0) {
402 sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
403 for (i = ENTROPYSOURCE - 1; i >= 0; i--) {
404 if (i >= RANDOM_PURE_START &&
405 (hc_source_mask & (1 << i)) == 0)
406 continue;
407 if (!first)
408 sbuf_cat(&sbuf, ",");
409 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "[" : "");
410 sbuf_cat(&sbuf, random_source_descr[i]);
411 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "]" : "");
412 first = false;
413 }
414 error = sbuf_finish(&sbuf);
415 sbuf_delete(&sbuf);
416 }
417 return (error);
418 }
419 SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask_symbolic,
420 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
421 random_print_harvestmask_symbolic, "A",
422 "Entropy harvesting mask (symbolic)");
423
424 /* ARGSUSED */
425 static void
random_harvestq_init(void * unused __unused)426 random_harvestq_init(void *unused __unused)
427 {
428 static const u_int almost_everything_mask =
429 (((1 << (RANDOM_ENVIRONMENTAL_END + 1)) - 1) &
430 ~_RANDOM_HARVEST_ETHER_OFF & ~_RANDOM_HARVEST_UMA_OFF);
431
432 hc_source_mask = almost_everything_mask;
433 RANDOM_HARVEST_INIT_LOCK();
434 harvest_context.hc_entropy_ring.in = harvest_context.hc_entropy_ring.out = 0;
435 }
436 SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_THIRD, random_harvestq_init, NULL);
437
438 /*
439 * Subroutine to slice up a contiguous chunk of 'entropy' and feed it into the
440 * underlying algorithm. Returns number of bytes actually fed into underlying
441 * algorithm.
442 */
443 static size_t
random_early_prime(char * entropy,size_t len)444 random_early_prime(char *entropy, size_t len)
445 {
446 struct harvest_event event;
447 size_t i;
448
449 len = rounddown(len, sizeof(event.he_entropy));
450 if (len == 0)
451 return (0);
452
453 for (i = 0; i < len; i += sizeof(event.he_entropy)) {
454 event.he_somecounter = (uint32_t)get_cyclecount();
455 event.he_size = sizeof(event.he_entropy);
456 event.he_source = RANDOM_CACHED;
457 event.he_destination =
458 harvest_context.hc_destination[RANDOM_CACHED]++;
459 memcpy(event.he_entropy, entropy + i, sizeof(event.he_entropy));
460 random_harvestq_fast_process_event(&event);
461 }
462 explicit_bzero(entropy, len);
463 return (len);
464 }
465
466 /*
467 * Subroutine to search for known loader-loaded files in memory and feed them
468 * into the underlying algorithm early in boot. Returns the number of bytes
469 * loaded (zero if none were loaded).
470 */
471 static size_t
random_prime_loader_file(const char * type)472 random_prime_loader_file(const char *type)
473 {
474 uint8_t *keyfile, *data;
475 size_t size;
476
477 keyfile = preload_search_by_type(type);
478 if (keyfile == NULL)
479 return (0);
480
481 data = preload_fetch_addr(keyfile);
482 size = preload_fetch_size(keyfile);
483 if (data == NULL)
484 return (0);
485
486 return (random_early_prime(data, size));
487 }
488
489 /*
490 * This is used to prime the RNG by grabbing any early random stuff
491 * known to the kernel, and inserting it directly into the hashing
492 * module, currently Fortuna.
493 */
494 /* ARGSUSED */
495 static void
random_harvestq_prime(void * unused __unused)496 random_harvestq_prime(void *unused __unused)
497 {
498 size_t size;
499
500 /*
501 * Get entropy that may have been preloaded by loader(8)
502 * and use it to pre-charge the entropy harvest queue.
503 */
504 size = random_prime_loader_file(RANDOM_CACHED_BOOT_ENTROPY_MODULE);
505 if (bootverbose) {
506 if (size > 0)
507 printf("random: read %zu bytes from preloaded cache\n",
508 size);
509 else
510 printf("random: no preloaded entropy cache\n");
511 }
512 size = random_prime_loader_file(RANDOM_PLATFORM_BOOT_ENTROPY_MODULE);
513 if (bootverbose) {
514 if (size > 0)
515 printf("random: read %zu bytes from platform bootloader\n",
516 size);
517 else
518 printf("random: no platform bootloader entropy\n");
519 }
520 }
521 SYSINIT(random_device_prime, SI_SUB_RANDOM, SI_ORDER_MIDDLE, random_harvestq_prime, NULL);
522
523 /* ARGSUSED */
524 static void
random_harvestq_deinit(void * unused __unused)525 random_harvestq_deinit(void *unused __unused)
526 {
527
528 /* Command the hash/reseed thread to end and wait for it to finish */
529 random_kthread_control = 0;
530 while (random_kthread_control >= 0)
531 tsleep(&harvest_context.hc_kthread_proc, 0, "harvqterm", hz/5);
532 }
533 SYSUNINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_THIRD, random_harvestq_deinit, NULL);
534
535 /*-
536 * Entropy harvesting queue routine.
537 *
538 * This is supposed to be fast; do not do anything slow in here!
539 * It is also illegal (and morally reprehensible) to insert any
540 * high-rate data here. "High-rate" is defined as a data source
541 * that will usually cause lots of failures of the "Lockless read"
542 * check a few lines below. This includes the "always-on" sources
543 * like the Intel "rdrand" or the VIA Nehamiah "xstore" sources.
544 */
545 /* XXXRW: get_cyclecount() is cheap on most modern hardware, where cycle
546 * counters are built in, but on older hardware it will do a real time clock
547 * read which can be quite expensive.
548 */
549 void
random_harvest_queue_(const void * entropy,u_int size,enum random_entropy_source origin)550 random_harvest_queue_(const void *entropy, u_int size, enum random_entropy_source origin)
551 {
552 struct harvest_event *event;
553 u_int ring_in;
554
555 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin));
556 RANDOM_HARVEST_LOCK();
557 ring_in = (harvest_context.hc_entropy_ring.in + 1)%RANDOM_RING_MAX;
558 if (ring_in != harvest_context.hc_entropy_ring.out) {
559 /* The ring is not full */
560 event = harvest_context.hc_entropy_ring.ring + ring_in;
561 event->he_somecounter = (uint32_t)get_cyclecount();
562 event->he_source = origin;
563 event->he_destination = harvest_context.hc_destination[origin]++;
564 if (size <= sizeof(event->he_entropy)) {
565 event->he_size = size;
566 memcpy(event->he_entropy, entropy, size);
567 }
568 else {
569 /* Big event, so squash it */
570 event->he_size = sizeof(event->he_entropy[0]);
571 event->he_entropy[0] = jenkins_hash(entropy, size, (uint32_t)(uintptr_t)event);
572 }
573 harvest_context.hc_entropy_ring.in = ring_in;
574 }
575 RANDOM_HARVEST_UNLOCK();
576 }
577
578 /*-
579 * Entropy harvesting fast routine.
580 *
581 * This is supposed to be very fast; do not do anything slow in here!
582 * This is the right place for high-rate harvested data.
583 */
584 void
random_harvest_fast_(const void * entropy,u_int size)585 random_harvest_fast_(const void *entropy, u_int size)
586 {
587 u_int pos;
588
589 pos = harvest_context.hc_entropy_fast_accumulator.pos;
590 harvest_context.hc_entropy_fast_accumulator.buf[pos] ^= jenkins_hash(entropy, size, (uint32_t)get_cyclecount());
591 harvest_context.hc_entropy_fast_accumulator.pos = (pos + 1)%RANDOM_ACCUM_MAX;
592 }
593
594 /*-
595 * Entropy harvesting direct routine.
596 *
597 * This is not supposed to be fast, but will only be used during
598 * (e.g.) booting when initial entropy is being gathered.
599 */
600 void
random_harvest_direct_(const void * entropy,u_int size,enum random_entropy_source origin)601 random_harvest_direct_(const void *entropy, u_int size, enum random_entropy_source origin)
602 {
603 struct harvest_event event;
604
605 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin));
606 size = MIN(size, sizeof(event.he_entropy));
607 event.he_somecounter = (uint32_t)get_cyclecount();
608 event.he_size = size;
609 event.he_source = origin;
610 event.he_destination = harvest_context.hc_destination[origin]++;
611 memcpy(event.he_entropy, entropy, size);
612 random_harvestq_fast_process_event(&event);
613 }
614
615 void
random_harvest_register_source(enum random_entropy_source source)616 random_harvest_register_source(enum random_entropy_source source)
617 {
618
619 hc_source_mask |= (1 << source);
620 }
621
622 void
random_harvest_deregister_source(enum random_entropy_source source)623 random_harvest_deregister_source(enum random_entropy_source source)
624 {
625
626 hc_source_mask &= ~(1 << source);
627 }
628
629 void
random_source_register(struct random_source * rsource)630 random_source_register(struct random_source *rsource)
631 {
632 struct random_sources *rrs;
633
634 KASSERT(rsource != NULL, ("invalid input to %s", __func__));
635
636 rrs = malloc(sizeof(*rrs), M_ENTROPY, M_WAITOK);
637 rrs->rrs_source = rsource;
638
639 random_harvest_register_source(rsource->rs_source);
640
641 printf("random: registering fast source %s\n", rsource->rs_ident);
642
643 RANDOM_HARVEST_LOCK();
644 CK_LIST_INSERT_HEAD(&source_list, rrs, rrs_entries);
645 RANDOM_HARVEST_UNLOCK();
646 }
647
648 void
random_source_deregister(struct random_source * rsource)649 random_source_deregister(struct random_source *rsource)
650 {
651 struct random_sources *rrs = NULL;
652
653 KASSERT(rsource != NULL, ("invalid input to %s", __func__));
654
655 random_harvest_deregister_source(rsource->rs_source);
656
657 RANDOM_HARVEST_LOCK();
658 CK_LIST_FOREACH(rrs, &source_list, rrs_entries)
659 if (rrs->rrs_source == rsource) {
660 CK_LIST_REMOVE(rrs, rrs_entries);
661 break;
662 }
663 RANDOM_HARVEST_UNLOCK();
664
665 if (rrs != NULL && epoch_inited)
666 epoch_wait_preempt(rs_epoch);
667 free(rrs, M_ENTROPY);
668 }
669
670 static int
random_source_handler(SYSCTL_HANDLER_ARGS)671 random_source_handler(SYSCTL_HANDLER_ARGS)
672 {
673 struct epoch_tracker et;
674 struct random_sources *rrs;
675 struct sbuf sbuf;
676 int error, count;
677
678 error = sysctl_wire_old_buffer(req, 0);
679 if (error != 0)
680 return (error);
681
682 sbuf_new_for_sysctl(&sbuf, NULL, 64, req);
683 count = 0;
684 epoch_enter_preempt(rs_epoch, &et);
685 CK_LIST_FOREACH(rrs, &source_list, rrs_entries) {
686 sbuf_cat(&sbuf, (count++ ? ",'" : "'"));
687 sbuf_cat(&sbuf, rrs->rrs_source->rs_ident);
688 sbuf_cat(&sbuf, "'");
689 }
690 epoch_exit_preempt(rs_epoch, &et);
691 error = sbuf_finish(&sbuf);
692 sbuf_delete(&sbuf);
693 return (error);
694 }
695 SYSCTL_PROC(_kern_random, OID_AUTO, random_sources, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
696 NULL, 0, random_source_handler, "A",
697 "List of active fast entropy sources.");
698
699 MODULE_VERSION(random_harvestq, 1);
700