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/cdefs.h>
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/ck.h>
36 #include <sys/conf.h>
37 #include <sys/epoch.h>
38 #include <sys/eventhandler.h>
39 #include <sys/hash.h>
40 #include <sys/kernel.h>
41 #include <sys/kthread.h>
42 #include <sys/linker.h>
43 #include <sys/lock.h>
44 #include <sys/malloc.h>
45 #include <sys/module.h>
46 #include <sys/mutex.h>
47 #include <sys/random.h>
48 #include <sys/sbuf.h>
49 #include <sys/sysctl.h>
50 #include <sys/unistd.h>
51
52 #include <machine/atomic.h>
53 #include <machine/cpu.h>
54
55 #include <crypto/rijndael/rijndael-api-fst.h>
56 #include <crypto/sha2/sha256.h>
57
58 #include <dev/random/hash.h>
59 #include <dev/random/randomdev.h>
60 #include <dev/random/random_harvestq.h>
61
62 #if defined(RANDOM_ENABLE_ETHER)
63 #define _RANDOM_HARVEST_ETHER_OFF 0
64 #else
65 #define _RANDOM_HARVEST_ETHER_OFF (1u << RANDOM_NET_ETHER)
66 #endif
67 #if defined(RANDOM_ENABLE_UMA)
68 #define _RANDOM_HARVEST_UMA_OFF 0
69 #else
70 #define _RANDOM_HARVEST_UMA_OFF (1u << RANDOM_UMA)
71 #endif
72
73 /*
74 * Note that random_sources_feed() will also use this to try and split up
75 * entropy into a subset of pools per iteration with the goal of feeding
76 * HARVESTSIZE into every pool at least once per second.
77 */
78 #define RANDOM_KTHREAD_HZ 10
79
80 static void random_kthread(void);
81 static void random_sources_feed(void);
82
83 /*
84 * Random must initialize much earlier than epoch, but we can initialize the
85 * epoch code before SMP starts. Prior to SMP, we can safely bypass
86 * concurrency primitives.
87 */
88 static __read_mostly bool epoch_inited;
89 static __read_mostly epoch_t rs_epoch;
90
91 /*
92 * How many events to queue up. We create this many items in
93 * an 'empty' queue, then transfer them to the 'harvest' queue with
94 * supplied junk. When used, they are transferred back to the
95 * 'empty' queue.
96 */
97 #define RANDOM_RING_MAX 1024
98 #define RANDOM_ACCUM_MAX 8
99
100 /* 1 to let the kernel thread run, 0 to terminate, -1 to mark completion */
101 volatile int random_kthread_control;
102
103
104 /* Allow the sysadmin to select the broad category of
105 * entropy types to harvest.
106 */
107 __read_frequently u_int hc_source_mask;
108
109 struct random_sources {
110 CK_LIST_ENTRY(random_sources) rrs_entries;
111 struct random_source *rrs_source;
112 };
113
114 static CK_LIST_HEAD(sources_head, random_sources) source_list =
115 CK_LIST_HEAD_INITIALIZER(source_list);
116
117 SYSCTL_NODE(_kern_random, OID_AUTO, harvest, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
118 "Entropy Device Parameters");
119
120 /*
121 * Put all the harvest queue context stuff in one place.
122 * this make is a bit easier to lock and protect.
123 */
124 static struct harvest_context {
125 /* The harvest mutex protects all of harvest_context and
126 * the related data.
127 */
128 struct mtx hc_mtx;
129 /* Round-robin destination cache. */
130 u_int hc_destination[ENTROPYSOURCE];
131 /* The context of the kernel thread processing harvested entropy */
132 struct proc *hc_kthread_proc;
133 /*
134 * Lockless ring buffer holding entropy events
135 * If ring.in == ring.out,
136 * the buffer is empty.
137 * If ring.in != ring.out,
138 * the buffer contains harvested entropy.
139 * If (ring.in + 1) == ring.out (mod RANDOM_RING_MAX),
140 * the buffer is full.
141 *
142 * NOTE: ring.in points to the last added element,
143 * and ring.out points to the last consumed element.
144 *
145 * The ring.in variable needs locking as there are multiple
146 * sources to the ring. Only the sources may change ring.in,
147 * but the consumer may examine it.
148 *
149 * The ring.out variable does not need locking as there is
150 * only one consumer. Only the consumer may change ring.out,
151 * but the sources may examine it.
152 */
153 struct entropy_ring {
154 struct harvest_event ring[RANDOM_RING_MAX];
155 volatile u_int in;
156 volatile u_int out;
157 } hc_entropy_ring;
158 struct fast_entropy_accumulator {
159 volatile u_int pos;
160 uint32_t buf[RANDOM_ACCUM_MAX];
161 } hc_entropy_fast_accumulator;
162 } harvest_context;
163
164 static struct kproc_desc random_proc_kp = {
165 "rand_harvestq",
166 random_kthread,
167 &harvest_context.hc_kthread_proc,
168 };
169
170 /* Pass the given event straight through to Fortuna/Whatever. */
171 static __inline void
random_harvestq_fast_process_event(struct harvest_event * event)172 random_harvestq_fast_process_event(struct harvest_event *event)
173 {
174 p_random_alg_context->ra_event_processor(event);
175 explicit_bzero(event, sizeof(*event));
176 }
177
178 static void
random_kthread(void)179 random_kthread(void)
180 {
181 u_int maxloop, ring_out, i;
182
183 /*
184 * Locking is not needed as this is the only place we modify ring.out, and
185 * we only examine ring.in without changing it. Both of these are volatile,
186 * and this is a unique thread.
187 */
188 for (random_kthread_control = 1; random_kthread_control;) {
189 /* Deal with events, if any. Restrict the number we do in one go. */
190 maxloop = RANDOM_RING_MAX;
191 while (harvest_context.hc_entropy_ring.out != harvest_context.hc_entropy_ring.in) {
192 ring_out = (harvest_context.hc_entropy_ring.out + 1)%RANDOM_RING_MAX;
193 random_harvestq_fast_process_event(harvest_context.hc_entropy_ring.ring + ring_out);
194 harvest_context.hc_entropy_ring.out = ring_out;
195 if (!--maxloop)
196 break;
197 }
198 random_sources_feed();
199 /* XXX: FIX!! Increase the high-performance data rate? Need some measurements first. */
200 for (i = 0; i < RANDOM_ACCUM_MAX; i++) {
201 if (harvest_context.hc_entropy_fast_accumulator.buf[i]) {
202 random_harvest_direct(harvest_context.hc_entropy_fast_accumulator.buf + i, sizeof(harvest_context.hc_entropy_fast_accumulator.buf[0]), RANDOM_UMA);
203 harvest_context.hc_entropy_fast_accumulator.buf[i] = 0;
204 }
205 }
206 /* XXX: FIX!! This is a *great* place to pass hardware/live entropy to random(9) */
207 tsleep_sbt(&harvest_context.hc_kthread_proc, 0, "-",
208 SBT_1S/RANDOM_KTHREAD_HZ, 0, C_PREL(1));
209 }
210 random_kthread_control = -1;
211 wakeup(&harvest_context.hc_kthread_proc);
212 kproc_exit(0);
213 /* NOTREACHED */
214 }
215 /* This happens well after SI_SUB_RANDOM */
216 SYSINIT(random_device_h_proc, SI_SUB_KICK_SCHEDULER, SI_ORDER_ANY, kproc_start,
217 &random_proc_kp);
218
219 static void
rs_epoch_init(void * dummy __unused)220 rs_epoch_init(void *dummy __unused)
221 {
222 rs_epoch = epoch_alloc("Random Sources", EPOCH_PREEMPT);
223 epoch_inited = true;
224 }
225 SYSINIT(rs_epoch_init, SI_SUB_EPOCH, SI_ORDER_ANY, rs_epoch_init, NULL);
226
227 /*
228 * Run through all fast sources reading entropy for the given
229 * number of rounds, which should be a multiple of the number
230 * of entropy accumulation pools in use; it is 32 for Fortuna.
231 */
232 static void
random_sources_feed(void)233 random_sources_feed(void)
234 {
235 uint32_t entropy[HARVESTSIZE];
236 struct epoch_tracker et;
237 struct random_sources *rrs;
238 u_int i, n, npools;
239 bool rse_warm;
240
241 rse_warm = epoch_inited;
242
243 /*
244 * Evenly-ish distribute pool population across the second based on how
245 * frequently random_kthread iterates.
246 *
247 * For Fortuna, the math currently works out as such:
248 *
249 * 64 bits * 4 pools = 256 bits per iteration
250 * 256 bits * 10 Hz = 2560 bits per second, 320 B/s
251 *
252 */
253 npools = howmany(p_random_alg_context->ra_poolcount, RANDOM_KTHREAD_HZ);
254
255 /*
256 * Step over all of live entropy sources, and feed their output
257 * to the system-wide RNG.
258 */
259 if (rse_warm)
260 epoch_enter_preempt(rs_epoch, &et);
261 CK_LIST_FOREACH(rrs, &source_list, rrs_entries) {
262 for (i = 0; i < npools; i++) {
263 n = rrs->rrs_source->rs_read(entropy, sizeof(entropy));
264 KASSERT((n <= sizeof(entropy)), ("%s: rs_read returned too much data (%u > %zu)", __func__, n, sizeof(entropy)));
265 /*
266 * Sometimes the HW entropy source doesn't have anything
267 * ready for us. This isn't necessarily untrustworthy.
268 * We don't perform any other verification of an entropy
269 * source (i.e., length is allowed to be anywhere from 1
270 * to sizeof(entropy), quality is unchecked, etc), so
271 * don't balk verbosely at slow random sources either.
272 * There are reports that RDSEED on x86 metal falls
273 * behind the rate at which we query it, for example.
274 * But it's still a better entropy source than RDRAND.
275 */
276 if (n == 0)
277 continue;
278 random_harvest_direct(entropy, n, rrs->rrs_source->rs_source);
279 }
280 }
281 if (rse_warm)
282 epoch_exit_preempt(rs_epoch, &et);
283 explicit_bzero(entropy, sizeof(entropy));
284 }
285
286 void
read_rate_increment(u_int chunk)287 read_rate_increment(u_int chunk)
288 {
289
290 /* Stubbed to maintain KBI; removed in FreeBSD 14.0. */
291 }
292
293 /* ARGSUSED */
294 static int
random_check_uint_harvestmask(SYSCTL_HANDLER_ARGS)295 random_check_uint_harvestmask(SYSCTL_HANDLER_ARGS)
296 {
297 static const u_int user_immutable_mask =
298 (((1 << ENTROPYSOURCE) - 1) & (-1UL << RANDOM_PURE_START)) |
299 _RANDOM_HARVEST_ETHER_OFF | _RANDOM_HARVEST_UMA_OFF;
300
301 int error;
302 u_int value, orig_value;
303
304 orig_value = value = hc_source_mask;
305 error = sysctl_handle_int(oidp, &value, 0, req);
306 if (error != 0 || req->newptr == NULL)
307 return (error);
308
309 if (flsl(value) > ENTROPYSOURCE)
310 return (EINVAL);
311
312 /*
313 * Disallow userspace modification of pure entropy sources.
314 */
315 hc_source_mask = (value & ~user_immutable_mask) |
316 (orig_value & user_immutable_mask);
317 return (0);
318 }
319 SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask,
320 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0,
321 random_check_uint_harvestmask, "IU",
322 "Entropy harvesting mask");
323
324 /* ARGSUSED */
325 static int
random_print_harvestmask(SYSCTL_HANDLER_ARGS)326 random_print_harvestmask(SYSCTL_HANDLER_ARGS)
327 {
328 struct sbuf sbuf;
329 int error, i;
330
331 error = sysctl_wire_old_buffer(req, 0);
332 if (error == 0) {
333 sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
334 for (i = ENTROPYSOURCE - 1; i >= 0; i--)
335 sbuf_cat(&sbuf, (hc_source_mask & (1 << i)) ? "1" : "0");
336 error = sbuf_finish(&sbuf);
337 sbuf_delete(&sbuf);
338 }
339 return (error);
340 }
341 SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask_bin,
342 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
343 random_print_harvestmask, "A",
344 "Entropy harvesting mask (printable)");
345
346 static const char *random_source_descr[ENTROPYSOURCE] = {
347 [RANDOM_CACHED] = "CACHED",
348 [RANDOM_ATTACH] = "ATTACH",
349 [RANDOM_KEYBOARD] = "KEYBOARD",
350 [RANDOM_MOUSE] = "MOUSE",
351 [RANDOM_NET_TUN] = "NET_TUN",
352 [RANDOM_NET_ETHER] = "NET_ETHER",
353 [RANDOM_NET_NG] = "NET_NG",
354 [RANDOM_INTERRUPT] = "INTERRUPT",
355 [RANDOM_SWI] = "SWI",
356 [RANDOM_FS_ATIME] = "FS_ATIME",
357 [RANDOM_UMA] = "UMA", /* ENVIRONMENTAL_END */
358 [RANDOM_PURE_OCTEON] = "PURE_OCTEON", /* PURE_START */
359 [RANDOM_PURE_SAFE] = "PURE_SAFE",
360 [RANDOM_PURE_GLXSB] = "PURE_GLXSB",
361 [RANDOM_PURE_HIFN] = "PURE_HIFN",
362 [RANDOM_PURE_RDRAND] = "PURE_RDRAND",
363 [RANDOM_PURE_NEHEMIAH] = "PURE_NEHEMIAH",
364 [RANDOM_PURE_RNDTEST] = "PURE_RNDTEST",
365 [RANDOM_PURE_VIRTIO] = "PURE_VIRTIO",
366 [RANDOM_PURE_BROADCOM] = "PURE_BROADCOM",
367 [RANDOM_PURE_CCP] = "PURE_CCP",
368 [RANDOM_PURE_DARN] = "PURE_DARN",
369 [RANDOM_PURE_TPM] = "PURE_TPM",
370 [RANDOM_PURE_VMGENID] = "VMGENID",
371 /* "ENTROPYSOURCE" */
372 };
373
374 /* ARGSUSED */
375 static int
random_print_harvestmask_symbolic(SYSCTL_HANDLER_ARGS)376 random_print_harvestmask_symbolic(SYSCTL_HANDLER_ARGS)
377 {
378 struct sbuf sbuf;
379 int error, i;
380 bool first;
381
382 first = true;
383 error = sysctl_wire_old_buffer(req, 0);
384 if (error == 0) {
385 sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
386 for (i = ENTROPYSOURCE - 1; i >= 0; i--) {
387 if (i >= RANDOM_PURE_START &&
388 (hc_source_mask & (1 << i)) == 0)
389 continue;
390 if (!first)
391 sbuf_cat(&sbuf, ",");
392 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "[" : "");
393 sbuf_cat(&sbuf, random_source_descr[i]);
394 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "]" : "");
395 first = false;
396 }
397 error = sbuf_finish(&sbuf);
398 sbuf_delete(&sbuf);
399 }
400 return (error);
401 }
402 SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask_symbolic,
403 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
404 random_print_harvestmask_symbolic, "A",
405 "Entropy harvesting mask (symbolic)");
406
407 /* ARGSUSED */
408 static void
random_harvestq_init(void * unused __unused)409 random_harvestq_init(void *unused __unused)
410 {
411 static const u_int almost_everything_mask =
412 (((1 << (RANDOM_ENVIRONMENTAL_END + 1)) - 1) &
413 ~_RANDOM_HARVEST_ETHER_OFF & ~_RANDOM_HARVEST_UMA_OFF);
414
415 hc_source_mask = almost_everything_mask;
416 RANDOM_HARVEST_INIT_LOCK();
417 harvest_context.hc_entropy_ring.in = harvest_context.hc_entropy_ring.out = 0;
418 }
419 SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_THIRD, random_harvestq_init, NULL);
420
421 /*
422 * Subroutine to slice up a contiguous chunk of 'entropy' and feed it into the
423 * underlying algorithm. Returns number of bytes actually fed into underlying
424 * algorithm.
425 */
426 static size_t
random_early_prime(char * entropy,size_t len)427 random_early_prime(char *entropy, size_t len)
428 {
429 struct harvest_event event;
430 size_t i;
431
432 len = rounddown(len, sizeof(event.he_entropy));
433 if (len == 0)
434 return (0);
435
436 for (i = 0; i < len; i += sizeof(event.he_entropy)) {
437 event.he_somecounter = (uint32_t)get_cyclecount();
438 event.he_size = sizeof(event.he_entropy);
439 event.he_source = RANDOM_CACHED;
440 event.he_destination =
441 harvest_context.hc_destination[RANDOM_CACHED]++;
442 memcpy(event.he_entropy, entropy + i, sizeof(event.he_entropy));
443 random_harvestq_fast_process_event(&event);
444 }
445 explicit_bzero(entropy, len);
446 return (len);
447 }
448
449 /*
450 * Subroutine to search for known loader-loaded files in memory and feed them
451 * into the underlying algorithm early in boot. Returns the number of bytes
452 * loaded (zero if none were loaded).
453 */
454 static size_t
random_prime_loader_file(const char * type)455 random_prime_loader_file(const char *type)
456 {
457 uint8_t *keyfile, *data;
458 size_t size;
459
460 keyfile = preload_search_by_type(type);
461 if (keyfile == NULL)
462 return (0);
463
464 data = preload_fetch_addr(keyfile);
465 size = preload_fetch_size(keyfile);
466 if (data == NULL)
467 return (0);
468
469 return (random_early_prime(data, size));
470 }
471
472 /*
473 * This is used to prime the RNG by grabbing any early random stuff
474 * known to the kernel, and inserting it directly into the hashing
475 * module, currently Fortuna.
476 */
477 /* ARGSUSED */
478 static void
random_harvestq_prime(void * unused __unused)479 random_harvestq_prime(void *unused __unused)
480 {
481 size_t size;
482
483 /*
484 * Get entropy that may have been preloaded by loader(8)
485 * and use it to pre-charge the entropy harvest queue.
486 */
487 size = random_prime_loader_file(RANDOM_CACHED_BOOT_ENTROPY_MODULE);
488 if (bootverbose) {
489 if (size > 0)
490 printf("random: read %zu bytes from preloaded cache\n",
491 size);
492 else
493 printf("random: no preloaded entropy cache\n");
494 }
495 size = random_prime_loader_file(RANDOM_PLATFORM_BOOT_ENTROPY_MODULE);
496 if (bootverbose) {
497 if (size > 0)
498 printf("random: read %zu bytes from platform bootloader\n",
499 size);
500 else
501 printf("random: no platform bootloader entropy\n");
502 }
503 }
504 SYSINIT(random_device_prime, SI_SUB_RANDOM, SI_ORDER_MIDDLE, random_harvestq_prime, NULL);
505
506 /* ARGSUSED */
507 static void
random_harvestq_deinit(void * unused __unused)508 random_harvestq_deinit(void *unused __unused)
509 {
510
511 /* Command the hash/reseed thread to end and wait for it to finish */
512 random_kthread_control = 0;
513 while (random_kthread_control >= 0)
514 tsleep(&harvest_context.hc_kthread_proc, 0, "harvqterm", hz/5);
515 }
516 SYSUNINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_THIRD, random_harvestq_deinit, NULL);
517
518 /*-
519 * Entropy harvesting queue routine.
520 *
521 * This is supposed to be fast; do not do anything slow in here!
522 * It is also illegal (and morally reprehensible) to insert any
523 * high-rate data here. "High-rate" is defined as a data source
524 * that will usually cause lots of failures of the "Lockless read"
525 * check a few lines below. This includes the "always-on" sources
526 * like the Intel "rdrand" or the VIA Nehamiah "xstore" sources.
527 */
528 /* XXXRW: get_cyclecount() is cheap on most modern hardware, where cycle
529 * counters are built in, but on older hardware it will do a real time clock
530 * read which can be quite expensive.
531 */
532 void
random_harvest_queue_(const void * entropy,u_int size,enum random_entropy_source origin)533 random_harvest_queue_(const void *entropy, u_int size, enum random_entropy_source origin)
534 {
535 struct harvest_event *event;
536 u_int ring_in;
537
538 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin));
539 RANDOM_HARVEST_LOCK();
540 ring_in = (harvest_context.hc_entropy_ring.in + 1)%RANDOM_RING_MAX;
541 if (ring_in != harvest_context.hc_entropy_ring.out) {
542 /* The ring is not full */
543 event = harvest_context.hc_entropy_ring.ring + ring_in;
544 event->he_somecounter = (uint32_t)get_cyclecount();
545 event->he_source = origin;
546 event->he_destination = harvest_context.hc_destination[origin]++;
547 if (size <= sizeof(event->he_entropy)) {
548 event->he_size = size;
549 memcpy(event->he_entropy, entropy, size);
550 }
551 else {
552 /* Big event, so squash it */
553 event->he_size = sizeof(event->he_entropy[0]);
554 event->he_entropy[0] = jenkins_hash(entropy, size, (uint32_t)(uintptr_t)event);
555 }
556 harvest_context.hc_entropy_ring.in = ring_in;
557 }
558 RANDOM_HARVEST_UNLOCK();
559 }
560
561 /*-
562 * Entropy harvesting fast routine.
563 *
564 * This is supposed to be very fast; do not do anything slow in here!
565 * This is the right place for high-rate harvested data.
566 */
567 void
random_harvest_fast_(const void * entropy,u_int size)568 random_harvest_fast_(const void *entropy, u_int size)
569 {
570 u_int pos;
571
572 pos = harvest_context.hc_entropy_fast_accumulator.pos;
573 harvest_context.hc_entropy_fast_accumulator.buf[pos] ^= jenkins_hash(entropy, size, (uint32_t)get_cyclecount());
574 harvest_context.hc_entropy_fast_accumulator.pos = (pos + 1)%RANDOM_ACCUM_MAX;
575 }
576
577 /*-
578 * Entropy harvesting direct routine.
579 *
580 * This is not supposed to be fast, but will only be used during
581 * (e.g.) booting when initial entropy is being gathered.
582 */
583 void
random_harvest_direct_(const void * entropy,u_int size,enum random_entropy_source origin)584 random_harvest_direct_(const void *entropy, u_int size, enum random_entropy_source origin)
585 {
586 struct harvest_event event;
587
588 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin));
589 size = MIN(size, sizeof(event.he_entropy));
590 event.he_somecounter = (uint32_t)get_cyclecount();
591 event.he_size = size;
592 event.he_source = origin;
593 event.he_destination = harvest_context.hc_destination[origin]++;
594 memcpy(event.he_entropy, entropy, size);
595 random_harvestq_fast_process_event(&event);
596 }
597
598 void
random_harvest_register_source(enum random_entropy_source source)599 random_harvest_register_source(enum random_entropy_source source)
600 {
601
602 hc_source_mask |= (1 << source);
603 }
604
605 void
random_harvest_deregister_source(enum random_entropy_source source)606 random_harvest_deregister_source(enum random_entropy_source source)
607 {
608
609 hc_source_mask &= ~(1 << source);
610 }
611
612 void
random_source_register(struct random_source * rsource)613 random_source_register(struct random_source *rsource)
614 {
615 struct random_sources *rrs;
616
617 KASSERT(rsource != NULL, ("invalid input to %s", __func__));
618
619 rrs = malloc(sizeof(*rrs), M_ENTROPY, M_WAITOK);
620 rrs->rrs_source = rsource;
621
622 random_harvest_register_source(rsource->rs_source);
623
624 printf("random: registering fast source %s\n", rsource->rs_ident);
625
626 RANDOM_HARVEST_LOCK();
627 CK_LIST_INSERT_HEAD(&source_list, rrs, rrs_entries);
628 RANDOM_HARVEST_UNLOCK();
629 }
630
631 void
random_source_deregister(struct random_source * rsource)632 random_source_deregister(struct random_source *rsource)
633 {
634 struct random_sources *rrs = NULL;
635
636 KASSERT(rsource != NULL, ("invalid input to %s", __func__));
637
638 random_harvest_deregister_source(rsource->rs_source);
639
640 RANDOM_HARVEST_LOCK();
641 CK_LIST_FOREACH(rrs, &source_list, rrs_entries)
642 if (rrs->rrs_source == rsource) {
643 CK_LIST_REMOVE(rrs, rrs_entries);
644 break;
645 }
646 RANDOM_HARVEST_UNLOCK();
647
648 if (rrs != NULL && epoch_inited)
649 epoch_wait_preempt(rs_epoch);
650 free(rrs, M_ENTROPY);
651 }
652
653 static int
random_source_handler(SYSCTL_HANDLER_ARGS)654 random_source_handler(SYSCTL_HANDLER_ARGS)
655 {
656 struct epoch_tracker et;
657 struct random_sources *rrs;
658 struct sbuf sbuf;
659 int error, count;
660
661 error = sysctl_wire_old_buffer(req, 0);
662 if (error != 0)
663 return (error);
664
665 sbuf_new_for_sysctl(&sbuf, NULL, 64, req);
666 count = 0;
667 epoch_enter_preempt(rs_epoch, &et);
668 CK_LIST_FOREACH(rrs, &source_list, rrs_entries) {
669 sbuf_cat(&sbuf, (count++ ? ",'" : "'"));
670 sbuf_cat(&sbuf, rrs->rrs_source->rs_ident);
671 sbuf_cat(&sbuf, "'");
672 }
673 epoch_exit_preempt(rs_epoch, &et);
674 error = sbuf_finish(&sbuf);
675 sbuf_delete(&sbuf);
676 return (error);
677 }
678 SYSCTL_PROC(_kern_random, OID_AUTO, random_sources, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
679 NULL, 0, random_source_handler, "A",
680 "List of active fast entropy sources.");
681
682 MODULE_VERSION(random_harvestq, 1);
683