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/fortuna.h> 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 static const char *random_source_descr[]; 92 93 /* 94 * How many events to queue up. We create this many items in 95 * an 'empty' queue, then transfer them to the 'harvest' queue with 96 * supplied junk. When used, they are transferred back to the 97 * 'empty' queue. 98 */ 99 #define RANDOM_RING_MAX 1024 100 #define RANDOM_ACCUM_MAX 8 101 102 /* 1 to let the kernel thread run, 0 to terminate, -1 to mark completion */ 103 volatile int random_kthread_control; 104 105 106 /* 107 * Allow the sysadmin to select the broad category of entropy types to harvest. 108 * 109 * Updates are synchronized by the harvest mutex. 110 */ 111 __read_frequently u_int hc_source_mask; 112 CTASSERT(ENTROPYSOURCE <= sizeof(hc_source_mask) * NBBY); 113 114 struct random_sources { 115 CK_LIST_ENTRY(random_sources) rrs_entries; 116 const struct random_source *rrs_source; 117 }; 118 119 static CK_LIST_HEAD(sources_head, random_sources) source_list = 120 CK_LIST_HEAD_INITIALIZER(source_list); 121 122 SYSCTL_NODE(_kern_random, OID_AUTO, harvest, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 123 "Entropy Device Parameters"); 124 125 /* 126 * Put all the harvest queue context stuff in one place. 127 * this make is a bit easier to lock and protect. 128 */ 129 static struct harvest_context { 130 /* The harvest mutex protects all of harvest_context and 131 * the related data. 132 */ 133 struct mtx hc_mtx; 134 /* Round-robin destination cache. */ 135 u_int hc_destination[ENTROPYSOURCE]; 136 /* The context of the kernel thread processing harvested entropy */ 137 struct proc *hc_kthread_proc; 138 /* 139 * A pair of buffers for queued events. New events are added to the 140 * active queue while the kthread processes the other one in parallel. 141 */ 142 struct entropy_buffer { 143 struct harvest_event ring[RANDOM_RING_MAX]; 144 u_int pos; 145 } hc_entropy_buf[2]; 146 u_int hc_active_buf; 147 struct fast_entropy_accumulator { 148 volatile u_int pos; 149 uint32_t buf[RANDOM_ACCUM_MAX]; 150 } hc_entropy_fast_accumulator; 151 } harvest_context; 152 153 #define RANDOM_HARVEST_INIT_LOCK() mtx_init(&harvest_context.hc_mtx, \ 154 "entropy harvest mutex", NULL, MTX_SPIN) 155 #define RANDOM_HARVEST_LOCK() mtx_lock_spin(&harvest_context.hc_mtx) 156 #define RANDOM_HARVEST_UNLOCK() mtx_unlock_spin(&harvest_context.hc_mtx) 157 158 static struct kproc_desc random_proc_kp = { 159 "rand_harvestq", 160 random_kthread, 161 &harvest_context.hc_kthread_proc, 162 }; 163 164 /* Pass the given event straight through to Fortuna/Whatever. */ 165 static __inline void 166 random_harvestq_fast_process_event(struct harvest_event *event) 167 { 168 p_random_alg_context->ra_event_processor(event); 169 explicit_bzero(event, sizeof(*event)); 170 } 171 172 static void 173 random_kthread(void) 174 { 175 struct harvest_context *hc; 176 177 hc = &harvest_context; 178 for (random_kthread_control = 1; random_kthread_control;) { 179 struct entropy_buffer *buf; 180 u_int entries; 181 182 /* Deal with queued events. */ 183 RANDOM_HARVEST_LOCK(); 184 buf = &hc->hc_entropy_buf[hc->hc_active_buf]; 185 entries = buf->pos; 186 buf->pos = 0; 187 hc->hc_active_buf = (hc->hc_active_buf + 1) % 188 nitems(hc->hc_entropy_buf); 189 RANDOM_HARVEST_UNLOCK(); 190 for (u_int i = 0; i < entries; i++) 191 random_harvestq_fast_process_event(&buf->ring[i]); 192 193 /* Poll sources of noise. */ 194 random_sources_feed(); 195 196 /* XXX: FIX!! Increase the high-performance data rate? Need some measurements first. */ 197 for (u_int i = 0; i < RANDOM_ACCUM_MAX; i++) { 198 if (hc->hc_entropy_fast_accumulator.buf[i]) { 199 random_harvest_direct(&hc->hc_entropy_fast_accumulator.buf[i], 200 sizeof(hc->hc_entropy_fast_accumulator.buf[0]), RANDOM_UMA); 201 hc->hc_entropy_fast_accumulator.buf[i] = 0; 202 } 203 } 204 /* XXX: FIX!! This is a *great* place to pass hardware/live entropy to random(9) */ 205 tsleep_sbt(&hc->hc_kthread_proc, 0, "-", 206 SBT_1S/RANDOM_KTHREAD_HZ, 0, C_PREL(1)); 207 } 208 random_kthread_control = -1; 209 wakeup(&hc->hc_kthread_proc); 210 kproc_exit(0); 211 /* NOTREACHED */ 212 } 213 SYSINIT(random_device_h_proc, SI_SUB_KICK_SCHEDULER, SI_ORDER_ANY, kproc_start, 214 &random_proc_kp); 215 _Static_assert(SI_SUB_KICK_SCHEDULER > SI_SUB_RANDOM, 216 "random kthread starting before subsystem initialization"); 217 218 static void 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 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 * We collect RANDOM_FORTUNA_DEFPOOLSIZE bytes per pool, i.e. enough 263 * to 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 * 274 RANDOM_FORTUNA_DEFPOOLSIZE, 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 if (rrs->rrs_source->rs_read == NULL) { 285 /* Source pushes entropy asynchronously. */ 286 continue; 287 } 288 n = rrs->rrs_source->rs_read(entropy, sizeof(entropy)); 289 KASSERT((n <= sizeof(entropy)), 290 ("%s: rs_read returned too much data (%u > %zu)", 291 __func__, n, sizeof(entropy))); 292 293 /* 294 * Sometimes the HW entropy source doesn't have anything 295 * ready for us. This isn't necessarily untrustworthy. 296 * We don't perform any other verification of an entropy 297 * source (i.e., length is allowed to be anywhere from 1 298 * to sizeof(entropy), quality is unchecked, etc), so 299 * don't balk verbosely at slow random sources either. 300 * There are reports that RDSEED on x86 metal falls 301 * behind the rate at which we query it, for example. 302 * But it's still a better entropy source than RDRAND. 303 */ 304 if (n == 0) 305 continue; 306 random_harvest_direct(entropy, n, rrs->rrs_source->rs_source); 307 } 308 } 309 if (rse_warm) 310 epoch_exit_preempt(rs_epoch, &et); 311 explicit_bzero(entropy, sizeof(entropy)); 312 } 313 314 /* 315 * State used for conducting NIST SP 800-90B health tests on entropy sources. 316 */ 317 static struct health_test_softc { 318 uint32_t ht_rct_value[HARVESTSIZE + 1]; 319 u_int ht_rct_count; /* number of samples with the same value */ 320 u_int ht_rct_limit; /* constant after init */ 321 322 uint32_t ht_apt_value[HARVESTSIZE + 1]; 323 u_int ht_apt_count; /* number of samples with the same value */ 324 u_int ht_apt_seq; /* sequence number of the last sample */ 325 u_int ht_apt_cutoff; /* constant after init */ 326 327 uint64_t ht_total_samples; 328 bool ondemand; /* Set to true to restart the state machine */ 329 enum { 330 INIT = 0, /* initial state */ 331 DISABLED, /* health checking is disabled */ 332 STARTUP, /* doing startup tests, samples are discarded */ 333 STEADY, /* steady-state operation */ 334 FAILED, /* health check failed, discard samples */ 335 } ht_state; 336 } healthtest[ENTROPYSOURCE]; 337 338 #define RANDOM_SELFTEST_STARTUP_SAMPLES 1024 /* 4.3, requirement 4 */ 339 #define RANDOM_SELFTEST_APT_WINDOW 512 /* 4.4.2 */ 340 341 static void 342 copy_event(uint32_t dst[static HARVESTSIZE + 1], 343 const struct harvest_event *event) 344 { 345 memset(dst, 0, sizeof(uint32_t) * (HARVESTSIZE + 1)); 346 memcpy(dst, event->he_entropy, event->he_size); 347 if (event->he_source <= RANDOM_ENVIRONMENTAL_END) { 348 /* 349 * For pure entropy sources the timestamp counter is generally 350 * quite determinstic since samples are taken at regular 351 * intervals, so does not contribute much to the entropy. To 352 * make health tests more effective, exclude it from the sample, 353 * since it might otherwise defeat the health tests in a 354 * scenario where the source is stuck. 355 */ 356 dst[HARVESTSIZE] = event->he_somecounter; 357 } 358 } 359 360 static void 361 random_healthtest_rct_init(struct health_test_softc *ht, 362 const struct harvest_event *event) 363 { 364 ht->ht_rct_count = 1; 365 copy_event(ht->ht_rct_value, event); 366 } 367 368 /* 369 * Apply the repitition count test to a sample. 370 * 371 * Return false if the test failed, i.e., we observed >= C consecutive samples 372 * with the same value, and true otherwise. 373 */ 374 static bool 375 random_healthtest_rct_next(struct health_test_softc *ht, 376 const struct harvest_event *event) 377 { 378 uint32_t val[HARVESTSIZE + 1]; 379 380 copy_event(val, event); 381 if (memcmp(val, ht->ht_rct_value, sizeof(ht->ht_rct_value)) != 0) { 382 ht->ht_rct_count = 1; 383 memcpy(ht->ht_rct_value, val, sizeof(ht->ht_rct_value)); 384 return (true); 385 } else { 386 ht->ht_rct_count++; 387 return (ht->ht_rct_count < ht->ht_rct_limit); 388 } 389 } 390 391 static void 392 random_healthtest_apt_init(struct health_test_softc *ht, 393 const struct harvest_event *event) 394 { 395 ht->ht_apt_count = 1; 396 ht->ht_apt_seq = 1; 397 copy_event(ht->ht_apt_value, event); 398 } 399 400 static bool 401 random_healthtest_apt_next(struct health_test_softc *ht, 402 const struct harvest_event *event) 403 { 404 uint32_t val[HARVESTSIZE + 1]; 405 406 if (ht->ht_apt_seq == 0) { 407 random_healthtest_apt_init(ht, event); 408 return (true); 409 } 410 411 copy_event(val, event); 412 if (memcmp(val, ht->ht_apt_value, sizeof(ht->ht_apt_value)) == 0) { 413 ht->ht_apt_count++; 414 if (ht->ht_apt_count >= ht->ht_apt_cutoff) 415 return (false); 416 } 417 418 ht->ht_apt_seq++; 419 if (ht->ht_apt_seq == RANDOM_SELFTEST_APT_WINDOW) 420 ht->ht_apt_seq = 0; 421 422 return (true); 423 } 424 425 /* 426 * Run the health tests for the given event. This is assumed to be called from 427 * a serialized context. 428 */ 429 bool 430 random_harvest_healthtest(const struct harvest_event *event) 431 { 432 struct health_test_softc *ht; 433 434 ht = &healthtest[event->he_source]; 435 436 /* 437 * Was on-demand testing requested? Restart the state machine if so, 438 * restarting the startup tests. 439 */ 440 if (atomic_load_bool(&ht->ondemand)) { 441 atomic_store_bool(&ht->ondemand, false); 442 ht->ht_state = INIT; 443 } 444 445 switch (ht->ht_state) { 446 case __predict_false(INIT): 447 /* Store the first sample and initialize test state. */ 448 random_healthtest_rct_init(ht, event); 449 random_healthtest_apt_init(ht, event); 450 ht->ht_total_samples = 0; 451 ht->ht_state = STARTUP; 452 return (false); 453 case DISABLED: 454 /* No health testing for this source. */ 455 return (true); 456 case STEADY: 457 case STARTUP: 458 ht->ht_total_samples++; 459 if (random_healthtest_rct_next(ht, event) && 460 random_healthtest_apt_next(ht, event)) { 461 if (ht->ht_state == STARTUP && 462 ht->ht_total_samples >= 463 RANDOM_SELFTEST_STARTUP_SAMPLES) { 464 printf( 465 "random: health test passed for source %s\n", 466 random_source_descr[event->he_source]); 467 ht->ht_state = STEADY; 468 } 469 return (ht->ht_state == STEADY); 470 } 471 ht->ht_state = FAILED; 472 printf( 473 "random: health test failed for source %s, discarding samples\n", 474 random_source_descr[event->he_source]); 475 /* FALLTHROUGH */ 476 case FAILED: 477 return (false); 478 } 479 } 480 481 static bool nist_healthtest_enabled = false; 482 SYSCTL_BOOL(_kern_random, OID_AUTO, nist_healthtest_enabled, 483 CTLFLAG_RDTUN, &nist_healthtest_enabled, 0, 484 "Enable NIST SP 800-90B health tests for noise sources"); 485 486 static void 487 random_healthtest_init(enum random_entropy_source source, int min_entropy) 488 { 489 struct health_test_softc *ht; 490 491 ht = &healthtest[source]; 492 memset(ht, 0, sizeof(*ht)); 493 KASSERT(ht->ht_state == INIT, 494 ("%s: health test state is %d for source %d", 495 __func__, ht->ht_state, source)); 496 497 /* 498 * If health-testing is enabled, validate all sources except CACHED and 499 * VMGENID: they are deterministic sources used only a small, fixed 500 * number of times, so statistical testing is not applicable. 501 */ 502 if (!nist_healthtest_enabled || 503 source == RANDOM_CACHED || source == RANDOM_PURE_VMGENID) { 504 ht->ht_state = DISABLED; 505 return; 506 } 507 508 /* 509 * Set cutoff values for the two tests, given a min-entropy estimate for 510 * the source and allowing for an error rate of 1 in 2^{34}. With a 511 * min-entropy estimate of 1 bit and a sample rate of RANDOM_KTHREAD_HZ, 512 * we expect to see an false positive once in ~54.5 years. 513 * 514 * The RCT limit comes from the formula in section 4.4.1. 515 * 516 * The APT cutoffs are calculated using the formula in section 4.4.2 517 * footnote 10 with the number of Bernoulli trials changed from W to 518 * W-1, since the test as written counts the number of samples equal to 519 * the first sample in the window, and thus tests W-1 samples. We 520 * provide cutoffs for estimates up to sizeof(uint32_t)*HARVESTSIZE*8 521 * bits. 522 */ 523 const int apt_cutoffs[] = { 524 [1] = 329, 525 [2] = 195, 526 [3] = 118, 527 [4] = 73, 528 [5] = 48, 529 [6] = 33, 530 [7] = 23, 531 [8] = 17, 532 [9] = 13, 533 [10] = 11, 534 [11] = 9, 535 [12] = 8, 536 [13] = 7, 537 [14] = 6, 538 [15] = 5, 539 [16] = 5, 540 [17 ... 19] = 4, 541 [20 ... 25] = 3, 542 [26 ... 42] = 2, 543 [43 ... 64] = 1, 544 }; 545 const int error_rate = 34; 546 547 if (min_entropy == 0) { 548 /* 549 * For environmental sources, the main source of entropy is the 550 * associated timecounter value. Since these sources can be 551 * influenced by unprivileged users, we conservatively use a 552 * min-entropy estimate of 1 bit per sample. For "pure" 553 * sources, we assume 8 bits per sample, as such sources provide 554 * a variable amount of data per read and in particular might 555 * only provide a single byte at a time. 556 */ 557 min_entropy = source >= RANDOM_PURE_START ? 8 : 1; 558 } else if (min_entropy < 0 || min_entropy >= nitems(apt_cutoffs)) { 559 panic("invalid min_entropy %d for %s", min_entropy, 560 random_source_descr[source]); 561 } 562 563 ht->ht_rct_limit = 1 + howmany(error_rate, min_entropy); 564 ht->ht_apt_cutoff = apt_cutoffs[min_entropy]; 565 } 566 567 static int 568 random_healthtest_ondemand(SYSCTL_HANDLER_ARGS) 569 { 570 u_int mask, source; 571 int error; 572 573 mask = 0; 574 error = sysctl_handle_int(oidp, &mask, 0, req); 575 if (error != 0 || req->newptr == NULL) 576 return (error); 577 578 while (mask != 0) { 579 source = ffs(mask) - 1; 580 if (source < nitems(healthtest)) 581 atomic_store_bool(&healthtest[source].ondemand, true); 582 mask &= ~(1u << source); 583 } 584 return (0); 585 } 586 SYSCTL_PROC(_kern_random, OID_AUTO, nist_healthtest_ondemand, 587 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0, 588 random_healthtest_ondemand, "I", 589 "Re-run NIST SP 800-90B startup health tests for a noise source"); 590 591 static int 592 random_check_uint_harvestmask(SYSCTL_HANDLER_ARGS) 593 { 594 static const u_int user_immutable_mask = 595 (((1 << ENTROPYSOURCE) - 1) & (-1UL << RANDOM_PURE_START)) | 596 _RANDOM_HARVEST_ETHER_OFF | _RANDOM_HARVEST_UMA_OFF; 597 598 int error; 599 u_int value; 600 601 value = atomic_load_int(&hc_source_mask); 602 error = sysctl_handle_int(oidp, &value, 0, req); 603 if (error != 0 || req->newptr == NULL) 604 return (error); 605 606 if (flsl(value) > ENTROPYSOURCE) 607 return (EINVAL); 608 609 /* 610 * Disallow userspace modification of pure entropy sources. 611 */ 612 RANDOM_HARVEST_LOCK(); 613 hc_source_mask = (value & ~user_immutable_mask) | 614 (hc_source_mask & user_immutable_mask); 615 RANDOM_HARVEST_UNLOCK(); 616 return (0); 617 } 618 SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask, 619 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0, 620 random_check_uint_harvestmask, "IU", 621 "Entropy harvesting mask"); 622 623 static int 624 random_print_harvestmask(SYSCTL_HANDLER_ARGS) 625 { 626 struct sbuf sbuf; 627 int error, i; 628 629 error = sysctl_wire_old_buffer(req, 0); 630 if (error == 0) { 631 u_int mask; 632 633 sbuf_new_for_sysctl(&sbuf, NULL, 128, req); 634 mask = atomic_load_int(&hc_source_mask); 635 for (i = ENTROPYSOURCE - 1; i >= 0; i--) { 636 bool present; 637 638 present = (mask & (1u << i)) != 0; 639 sbuf_cat(&sbuf, present ? "1" : "0"); 640 } 641 error = sbuf_finish(&sbuf); 642 sbuf_delete(&sbuf); 643 } 644 return (error); 645 } 646 SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask_bin, 647 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, 648 random_print_harvestmask, "A", 649 "Entropy harvesting mask (printable)"); 650 651 static const char *random_source_descr[/*ENTROPYSOURCE*/] = { 652 [RANDOM_CACHED] = "CACHED", 653 [RANDOM_ATTACH] = "ATTACH", 654 [RANDOM_KEYBOARD] = "KEYBOARD", 655 [RANDOM_MOUSE] = "MOUSE", 656 [RANDOM_NET_TUN] = "NET_TUN", 657 [RANDOM_NET_ETHER] = "NET_ETHER", 658 [RANDOM_NET_NG] = "NET_NG", 659 [RANDOM_INTERRUPT] = "INTERRUPT", 660 [RANDOM_SWI] = "SWI", 661 [RANDOM_FS_ATIME] = "FS_ATIME", 662 [RANDOM_UMA] = "UMA", 663 [RANDOM_CALLOUT] = "CALLOUT", 664 [RANDOM_RANDOMDEV] = "RANDOMDEV", /* ENVIRONMENTAL_END */ 665 [RANDOM_PURE_TPM] = "PURE_TPM", /* PURE_START */ 666 [RANDOM_PURE_RDRAND] = "PURE_RDRAND", 667 [RANDOM_PURE_RDSEED] = "PURE_RDSEED", 668 [RANDOM_PURE_NEHEMIAH] = "PURE_NEHEMIAH", 669 [RANDOM_PURE_RNDTEST] = "PURE_RNDTEST", 670 [RANDOM_PURE_VIRTIO] = "PURE_VIRTIO", 671 [RANDOM_PURE_BROADCOM] = "PURE_BROADCOM", 672 [RANDOM_PURE_CCP] = "PURE_CCP", 673 [RANDOM_PURE_DARN] = "PURE_DARN", 674 [RANDOM_PURE_VMGENID] = "PURE_VMGENID", 675 [RANDOM_PURE_QUALCOMM] = "PURE_QUALCOMM", 676 [RANDOM_PURE_ARMV8] = "PURE_ARMV8", 677 [RANDOM_PURE_ARM_TRNG] = "PURE_ARM_TRNG", 678 [RANDOM_PURE_SAFE] = "PURE_SAFE", 679 [RANDOM_PURE_GLXSB] = "PURE_GLXSB", 680 /* "ENTROPYSOURCE" */ 681 }; 682 CTASSERT(nitems(random_source_descr) == ENTROPYSOURCE); 683 684 static int 685 random_print_harvestmask_symbolic(SYSCTL_HANDLER_ARGS) 686 { 687 struct sbuf sbuf; 688 int error, i; 689 bool first; 690 691 first = true; 692 error = sysctl_wire_old_buffer(req, 0); 693 if (error == 0) { 694 u_int mask; 695 696 sbuf_new_for_sysctl(&sbuf, NULL, 128, req); 697 mask = atomic_load_int(&hc_source_mask); 698 for (i = ENTROPYSOURCE - 1; i >= 0; i--) { 699 bool present; 700 701 present = (mask & (1u << i)) != 0; 702 if (i >= RANDOM_PURE_START && !present) 703 continue; 704 if (!first) 705 sbuf_cat(&sbuf, ","); 706 sbuf_cat(&sbuf, !present ? "[" : ""); 707 sbuf_cat(&sbuf, random_source_descr[i]); 708 sbuf_cat(&sbuf, !present ? "]" : ""); 709 first = false; 710 } 711 error = sbuf_finish(&sbuf); 712 sbuf_delete(&sbuf); 713 } 714 return (error); 715 } 716 SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask_symbolic, 717 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, 718 random_print_harvestmask_symbolic, "A", 719 "Entropy harvesting mask (symbolic)"); 720 721 static void 722 random_harvestq_init(void *unused __unused) 723 { 724 static const u_int almost_everything_mask = 725 (((1 << (RANDOM_ENVIRONMENTAL_END + 1)) - 1) & 726 ~_RANDOM_HARVEST_ETHER_OFF & ~_RANDOM_HARVEST_UMA_OFF); 727 728 hc_source_mask = almost_everything_mask; 729 RANDOM_HARVEST_INIT_LOCK(); 730 harvest_context.hc_active_buf = 0; 731 732 for (int i = RANDOM_START; i <= RANDOM_ENVIRONMENTAL_END; i++) 733 random_healthtest_init(i, 0); 734 } 735 SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_THIRD, random_harvestq_init, NULL); 736 737 /* 738 * Subroutine to slice up a contiguous chunk of 'entropy' and feed it into the 739 * underlying algorithm. Returns number of bytes actually fed into underlying 740 * algorithm. 741 */ 742 static size_t 743 random_early_prime(char *entropy, size_t len) 744 { 745 struct harvest_event event; 746 size_t i; 747 748 len = rounddown(len, sizeof(event.he_entropy)); 749 if (len == 0) 750 return (0); 751 752 for (i = 0; i < len; i += sizeof(event.he_entropy)) { 753 event.he_somecounter = random_get_cyclecount(); 754 event.he_size = sizeof(event.he_entropy); 755 event.he_source = RANDOM_CACHED; 756 event.he_destination = 757 harvest_context.hc_destination[RANDOM_CACHED]++; 758 memcpy(event.he_entropy, entropy + i, sizeof(event.he_entropy)); 759 random_harvestq_fast_process_event(&event); 760 } 761 explicit_bzero(entropy, len); 762 return (len); 763 } 764 765 /* 766 * Subroutine to search for known loader-loaded files in memory and feed them 767 * into the underlying algorithm early in boot. Returns the number of bytes 768 * loaded (zero if none were loaded). 769 */ 770 static size_t 771 random_prime_loader_file(const char *type) 772 { 773 uint8_t *keyfile, *data; 774 size_t size; 775 776 keyfile = preload_search_by_type(type); 777 if (keyfile == NULL) 778 return (0); 779 780 data = preload_fetch_addr(keyfile); 781 size = preload_fetch_size(keyfile); 782 if (data == NULL) 783 return (0); 784 785 return (random_early_prime(data, size)); 786 } 787 788 /* 789 * This is used to prime the RNG by grabbing any early random stuff 790 * known to the kernel, and inserting it directly into the hashing 791 * module, currently Fortuna. 792 */ 793 static void 794 random_harvestq_prime(void *unused __unused) 795 { 796 size_t size; 797 798 /* 799 * Get entropy that may have been preloaded by loader(8) 800 * and use it to pre-charge the entropy harvest queue. 801 */ 802 size = random_prime_loader_file(RANDOM_CACHED_BOOT_ENTROPY_MODULE); 803 if (bootverbose) { 804 if (size > 0) 805 printf("random: read %zu bytes from preloaded cache\n", 806 size); 807 else 808 printf("random: no preloaded entropy cache\n"); 809 } 810 size = random_prime_loader_file(RANDOM_PLATFORM_BOOT_ENTROPY_MODULE); 811 if (bootverbose) { 812 if (size > 0) 813 printf("random: read %zu bytes from platform bootloader\n", 814 size); 815 else 816 printf("random: no platform bootloader entropy\n"); 817 } 818 } 819 SYSINIT(random_device_prime, SI_SUB_RANDOM, SI_ORDER_MIDDLE, random_harvestq_prime, NULL); 820 821 static void 822 random_harvestq_deinit(void *unused __unused) 823 { 824 825 /* Command the hash/reseed thread to end and wait for it to finish */ 826 random_kthread_control = 0; 827 while (random_kthread_control >= 0) 828 tsleep(&harvest_context.hc_kthread_proc, 0, "harvqterm", hz/5); 829 } 830 SYSUNINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_THIRD, random_harvestq_deinit, NULL); 831 832 /*- 833 * Entropy harvesting queue routine. 834 * 835 * This is supposed to be fast; do not do anything slow in here! 836 * It is also illegal (and morally reprehensible) to insert any 837 * high-rate data here. "High-rate" is defined as a data source 838 * that is likely to fill up the buffer in much less than 100ms. 839 * This includes the "always-on" sources like the Intel "rdrand" 840 * or the VIA Nehamiah "xstore" sources. 841 */ 842 /* XXXRW: get_cyclecount() is cheap on most modern hardware, where cycle 843 * counters are built in, but on older hardware it will do a real time clock 844 * read which can be quite expensive. 845 */ 846 void 847 random_harvest_queue_(const void *entropy, u_int size, enum random_entropy_source origin) 848 { 849 struct harvest_context *hc; 850 struct entropy_buffer *buf; 851 struct harvest_event *event; 852 853 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, 854 ("%s: origin %d invalid", __func__, origin)); 855 856 hc = &harvest_context; 857 RANDOM_HARVEST_LOCK(); 858 buf = &hc->hc_entropy_buf[hc->hc_active_buf]; 859 if (buf->pos < RANDOM_RING_MAX) { 860 event = &buf->ring[buf->pos++]; 861 event->he_somecounter = random_get_cyclecount(); 862 event->he_source = origin; 863 event->he_destination = hc->hc_destination[origin]++; 864 if (size <= sizeof(event->he_entropy)) { 865 event->he_size = size; 866 memcpy(event->he_entropy, entropy, size); 867 } else { 868 /* Big event, so squash it */ 869 event->he_size = sizeof(event->he_entropy[0]); 870 event->he_entropy[0] = jenkins_hash(entropy, size, (uint32_t)(uintptr_t)event); 871 } 872 } 873 RANDOM_HARVEST_UNLOCK(); 874 } 875 876 /*- 877 * Entropy harvesting fast routine. 878 * 879 * This is supposed to be very fast; do not do anything slow in here! 880 * This is the right place for high-rate harvested data. 881 */ 882 void 883 random_harvest_fast_(const void *entropy, u_int size) 884 { 885 u_int pos; 886 887 pos = harvest_context.hc_entropy_fast_accumulator.pos; 888 harvest_context.hc_entropy_fast_accumulator.buf[pos] ^= 889 jenkins_hash(entropy, size, random_get_cyclecount()); 890 harvest_context.hc_entropy_fast_accumulator.pos = (pos + 1)%RANDOM_ACCUM_MAX; 891 } 892 893 /*- 894 * Entropy harvesting direct routine. 895 * 896 * This is not supposed to be fast, but will only be used during 897 * (e.g.) booting when initial entropy is being gathered. 898 */ 899 void 900 random_harvest_direct_(const void *entropy, u_int size, enum random_entropy_source origin) 901 { 902 struct harvest_event event; 903 904 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin)); 905 size = MIN(size, sizeof(event.he_entropy)); 906 event.he_somecounter = random_get_cyclecount(); 907 event.he_size = size; 908 event.he_source = origin; 909 event.he_destination = harvest_context.hc_destination[origin]++; 910 memcpy(event.he_entropy, entropy, size); 911 random_harvestq_fast_process_event(&event); 912 } 913 914 void 915 random_source_register(const struct random_source *rsource) 916 { 917 struct random_sources *rrs; 918 919 KASSERT(rsource != NULL, ("invalid input to %s", __func__)); 920 921 rrs = malloc(sizeof(*rrs), M_ENTROPY, M_WAITOK); 922 rrs->rrs_source = rsource; 923 924 printf("random: registering fast source %s\n", rsource->rs_ident); 925 926 random_healthtest_init(rsource->rs_source, rsource->rs_min_entropy); 927 928 RANDOM_HARVEST_LOCK(); 929 hc_source_mask |= (1 << rsource->rs_source); 930 CK_LIST_INSERT_HEAD(&source_list, rrs, rrs_entries); 931 RANDOM_HARVEST_UNLOCK(); 932 } 933 934 void 935 random_source_deregister(const struct random_source *rsource) 936 { 937 struct random_sources *rrs = NULL; 938 939 KASSERT(rsource != NULL, ("invalid input to %s", __func__)); 940 941 RANDOM_HARVEST_LOCK(); 942 hc_source_mask &= ~(1 << rsource->rs_source); 943 CK_LIST_FOREACH(rrs, &source_list, rrs_entries) 944 if (rrs->rrs_source == rsource) { 945 CK_LIST_REMOVE(rrs, rrs_entries); 946 break; 947 } 948 RANDOM_HARVEST_UNLOCK(); 949 950 if (rrs != NULL && epoch_inited) 951 epoch_wait_preempt(rs_epoch); 952 free(rrs, M_ENTROPY); 953 } 954 955 static int 956 random_source_handler(SYSCTL_HANDLER_ARGS) 957 { 958 struct epoch_tracker et; 959 struct random_sources *rrs; 960 struct sbuf sbuf; 961 int error, count; 962 963 error = sysctl_wire_old_buffer(req, 0); 964 if (error != 0) 965 return (error); 966 967 sbuf_new_for_sysctl(&sbuf, NULL, 64, req); 968 count = 0; 969 epoch_enter_preempt(rs_epoch, &et); 970 CK_LIST_FOREACH(rrs, &source_list, rrs_entries) { 971 sbuf_cat(&sbuf, (count++ ? ",'" : "'")); 972 sbuf_cat(&sbuf, rrs->rrs_source->rs_ident); 973 sbuf_cat(&sbuf, "'"); 974 } 975 epoch_exit_preempt(rs_epoch, &et); 976 error = sbuf_finish(&sbuf); 977 sbuf_delete(&sbuf); 978 return (error); 979 } 980 SYSCTL_PROC(_kern_random, OID_AUTO, random_sources, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, 981 NULL, 0, random_source_handler, "A", 982 "List of active fast entropy sources."); 983 984 MODULE_VERSION(random_harvestq, 1); 985