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[ENTROPYSOURCE]; 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 /* Allow the sysadmin to select the broad category of 107 * entropy types to harvest. 108 */ 109 __read_frequently u_int hc_source_mask; 110 111 struct random_sources { 112 CK_LIST_ENTRY(random_sources) rrs_entries; 113 struct random_source *rrs_source; 114 }; 115 116 static CK_LIST_HEAD(sources_head, random_sources) source_list = 117 CK_LIST_HEAD_INITIALIZER(source_list); 118 119 SYSCTL_NODE(_kern_random, OID_AUTO, harvest, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 120 "Entropy Device Parameters"); 121 122 /* 123 * Put all the harvest queue context stuff in one place. 124 * this make is a bit easier to lock and protect. 125 */ 126 static struct harvest_context { 127 /* The harvest mutex protects all of harvest_context and 128 * the related data. 129 */ 130 struct mtx hc_mtx; 131 /* Round-robin destination cache. */ 132 u_int hc_destination[ENTROPYSOURCE]; 133 /* The context of the kernel thread processing harvested entropy */ 134 struct proc *hc_kthread_proc; 135 /* 136 * A pair of buffers for queued events. New events are added to the 137 * active queue while the kthread processes the other one in parallel. 138 */ 139 struct entropy_buffer { 140 struct harvest_event ring[RANDOM_RING_MAX]; 141 u_int pos; 142 } hc_entropy_buf[2]; 143 u_int hc_active_buf; 144 struct fast_entropy_accumulator { 145 volatile u_int pos; 146 uint32_t buf[RANDOM_ACCUM_MAX]; 147 } hc_entropy_fast_accumulator; 148 } harvest_context; 149 150 #define RANDOM_HARVEST_INIT_LOCK() mtx_init(&harvest_context.hc_mtx, \ 151 "entropy harvest mutex", NULL, MTX_SPIN) 152 #define RANDOM_HARVEST_LOCK() mtx_lock_spin(&harvest_context.hc_mtx) 153 #define RANDOM_HARVEST_UNLOCK() mtx_unlock_spin(&harvest_context.hc_mtx) 154 155 static struct kproc_desc random_proc_kp = { 156 "rand_harvestq", 157 random_kthread, 158 &harvest_context.hc_kthread_proc, 159 }; 160 161 /* Pass the given event straight through to Fortuna/Whatever. */ 162 static __inline void 163 random_harvestq_fast_process_event(struct harvest_event *event) 164 { 165 p_random_alg_context->ra_event_processor(event); 166 explicit_bzero(event, sizeof(*event)); 167 } 168 169 static void 170 random_kthread(void) 171 { 172 struct harvest_context *hc; 173 174 hc = &harvest_context; 175 for (random_kthread_control = 1; random_kthread_control;) { 176 struct entropy_buffer *buf; 177 u_int entries; 178 179 /* Deal with queued events. */ 180 RANDOM_HARVEST_LOCK(); 181 buf = &hc->hc_entropy_buf[hc->hc_active_buf]; 182 entries = buf->pos; 183 buf->pos = 0; 184 hc->hc_active_buf = (hc->hc_active_buf + 1) % 185 nitems(hc->hc_entropy_buf); 186 RANDOM_HARVEST_UNLOCK(); 187 for (u_int i = 0; i < entries; i++) 188 random_harvestq_fast_process_event(&buf->ring[i]); 189 190 /* Poll sources of noise. */ 191 random_sources_feed(); 192 193 /* XXX: FIX!! Increase the high-performance data rate? Need some measurements first. */ 194 for (u_int i = 0; i < RANDOM_ACCUM_MAX; i++) { 195 if (hc->hc_entropy_fast_accumulator.buf[i]) { 196 random_harvest_direct(&hc->hc_entropy_fast_accumulator.buf[i], 197 sizeof(hc->hc_entropy_fast_accumulator.buf[0]), RANDOM_UMA); 198 hc->hc_entropy_fast_accumulator.buf[i] = 0; 199 } 200 } 201 /* XXX: FIX!! This is a *great* place to pass hardware/live entropy to random(9) */ 202 tsleep_sbt(&hc->hc_kthread_proc, 0, "-", 203 SBT_1S/RANDOM_KTHREAD_HZ, 0, C_PREL(1)); 204 } 205 random_kthread_control = -1; 206 wakeup(&hc->hc_kthread_proc); 207 kproc_exit(0); 208 /* NOTREACHED */ 209 } 210 SYSINIT(random_device_h_proc, SI_SUB_KICK_SCHEDULER, SI_ORDER_ANY, kproc_start, 211 &random_proc_kp); 212 _Static_assert(SI_SUB_KICK_SCHEDULER > SI_SUB_RANDOM, 213 "random kthread starting before subsystem initialization"); 214 215 static void 216 rs_epoch_init(void *dummy __unused) 217 { 218 rs_epoch = epoch_alloc("Random Sources", EPOCH_PREEMPT); 219 epoch_inited = true; 220 } 221 SYSINIT(rs_epoch_init, SI_SUB_EPOCH, SI_ORDER_ANY, rs_epoch_init, NULL); 222 223 /* 224 * Run through all fast sources reading entropy for the given 225 * number of rounds, which should be a multiple of the number 226 * of entropy accumulation pools in use; it is 32 for Fortuna. 227 */ 228 static void 229 random_sources_feed(void) 230 { 231 uint32_t entropy[HARVESTSIZE]; 232 struct epoch_tracker et; 233 struct random_sources *rrs; 234 u_int i, n, npools; 235 bool rse_warm; 236 237 rse_warm = epoch_inited; 238 239 /* 240 * Evenly-ish distribute pool population across the second based on how 241 * frequently random_kthread iterates. 242 * 243 * For Fortuna, the math currently works out as such: 244 * 245 * 64 bits * 4 pools = 256 bits per iteration 246 * 256 bits * 10 Hz = 2560 bits per second, 320 B/s 247 * 248 */ 249 npools = howmany(p_random_alg_context->ra_poolcount, RANDOM_KTHREAD_HZ); 250 251 /*- 252 * If we're not seeded yet, attempt to perform a "full seed", filling 253 * all of the PRNG's pools with entropy; if there is enough entropy 254 * available from "fast" entropy sources this will allow us to finish 255 * seeding and unblock the boot process immediately rather than being 256 * stuck for a few seconds with random_kthread gradually collecting a 257 * small chunk of entropy every 1 / RANDOM_KTHREAD_HZ seconds. 258 * 259 * We collect RANDOM_FORTUNA_DEFPOOLSIZE bytes per pool, i.e. enough 260 * to fill Fortuna's pools in the default configuration. With another 261 * PRNG or smaller pools for Fortuna, we might collect more entropy 262 * than needed to fill the pools, but this is harmless; alternatively, 263 * a different PRNG, larger pools, or fast entropy sources which are 264 * not able to provide as much entropy as we request may result in the 265 * not being fully seeded (and thus remaining blocked) but in that 266 * case we will return here after 1 / RANDOM_KTHREAD_HZ seconds and 267 * try again for a large amount of entropy. 268 */ 269 if (!p_random_alg_context->ra_seeded()) 270 npools = howmany(p_random_alg_context->ra_poolcount * 271 RANDOM_FORTUNA_DEFPOOLSIZE, sizeof(entropy)); 272 273 /* 274 * Step over all of live entropy sources, and feed their output 275 * to the system-wide RNG. 276 */ 277 if (rse_warm) 278 epoch_enter_preempt(rs_epoch, &et); 279 CK_LIST_FOREACH(rrs, &source_list, rrs_entries) { 280 for (i = 0; i < npools; i++) { 281 n = rrs->rrs_source->rs_read(entropy, sizeof(entropy)); 282 KASSERT((n <= sizeof(entropy)), ("%s: rs_read returned too much data (%u > %zu)", __func__, n, sizeof(entropy))); 283 /* 284 * Sometimes the HW entropy source doesn't have anything 285 * ready for us. This isn't necessarily untrustworthy. 286 * We don't perform any other verification of an entropy 287 * source (i.e., length is allowed to be anywhere from 1 288 * to sizeof(entropy), quality is unchecked, etc), so 289 * don't balk verbosely at slow random sources either. 290 * There are reports that RDSEED on x86 metal falls 291 * behind the rate at which we query it, for example. 292 * But it's still a better entropy source than RDRAND. 293 */ 294 if (n == 0) 295 continue; 296 random_harvest_direct(entropy, n, rrs->rrs_source->rs_source); 297 } 298 } 299 if (rse_warm) 300 epoch_exit_preempt(rs_epoch, &et); 301 explicit_bzero(entropy, sizeof(entropy)); 302 } 303 304 /* 305 * State used for conducting NIST SP 800-90B health tests on entropy sources. 306 */ 307 static struct health_test_softc { 308 uint32_t ht_rct_value[HARVESTSIZE + 1]; 309 u_int ht_rct_count; /* number of samples with the same value */ 310 u_int ht_rct_limit; /* constant after init */ 311 312 uint32_t ht_apt_value[HARVESTSIZE + 1]; 313 u_int ht_apt_count; /* number of samples with the same value */ 314 u_int ht_apt_seq; /* sequence number of the last sample */ 315 u_int ht_apt_cutoff; /* constant after init */ 316 317 uint64_t ht_total_samples; 318 bool ondemand; /* Set to true to restart the state machine */ 319 enum { 320 INIT = 0, /* initial state */ 321 DISABLED, /* health checking is disabled */ 322 STARTUP, /* doing startup tests, samples are discarded */ 323 STEADY, /* steady-state operation */ 324 FAILED, /* health check failed, discard samples */ 325 } ht_state; 326 } healthtest[ENTROPYSOURCE]; 327 328 #define RANDOM_SELFTEST_STARTUP_SAMPLES 1024 /* 4.3, requirement 4 */ 329 #define RANDOM_SELFTEST_APT_WINDOW 512 /* 4.4.2 */ 330 331 static void 332 copy_event(uint32_t dst[static HARVESTSIZE + 1], 333 const struct harvest_event *event) 334 { 335 memset(dst, 0, sizeof(uint32_t) * (HARVESTSIZE + 1)); 336 memcpy(dst, event->he_entropy, event->he_size); 337 dst[HARVESTSIZE] = event->he_somecounter; 338 } 339 340 static void 341 random_healthtest_rct_init(struct health_test_softc *ht, 342 const struct harvest_event *event) 343 { 344 ht->ht_rct_count = 1; 345 copy_event(ht->ht_rct_value, event); 346 } 347 348 /* 349 * Apply the repitition count test to a sample. 350 * 351 * Return false if the test failed, i.e., we observed >= C consecutive samples 352 * with the same value, and true otherwise. 353 */ 354 static bool 355 random_healthtest_rct_next(struct health_test_softc *ht, 356 const struct harvest_event *event) 357 { 358 uint32_t val[HARVESTSIZE + 1]; 359 360 copy_event(val, event); 361 if (memcmp(val, ht->ht_rct_value, sizeof(ht->ht_rct_value)) != 0) { 362 ht->ht_rct_count = 1; 363 memcpy(ht->ht_rct_value, val, sizeof(ht->ht_rct_value)); 364 return (true); 365 } else { 366 ht->ht_rct_count++; 367 return (ht->ht_rct_count < ht->ht_rct_limit); 368 } 369 } 370 371 static void 372 random_healthtest_apt_init(struct health_test_softc *ht, 373 const struct harvest_event *event) 374 { 375 ht->ht_apt_count = 1; 376 ht->ht_apt_seq = 1; 377 copy_event(ht->ht_apt_value, event); 378 } 379 380 static bool 381 random_healthtest_apt_next(struct health_test_softc *ht, 382 const struct harvest_event *event) 383 { 384 uint32_t val[HARVESTSIZE + 1]; 385 386 if (ht->ht_apt_seq == 0) { 387 random_healthtest_apt_init(ht, event); 388 return (true); 389 } 390 391 copy_event(val, event); 392 if (memcmp(val, ht->ht_apt_value, sizeof(ht->ht_apt_value)) == 0) { 393 ht->ht_apt_count++; 394 if (ht->ht_apt_count >= ht->ht_apt_cutoff) 395 return (false); 396 } 397 398 ht->ht_apt_seq++; 399 if (ht->ht_apt_seq == RANDOM_SELFTEST_APT_WINDOW) 400 ht->ht_apt_seq = 0; 401 402 return (true); 403 } 404 405 /* 406 * Run the health tests for the given event. This is assumed to be called from 407 * a serialized context. 408 */ 409 bool 410 random_harvest_healthtest(const struct harvest_event *event) 411 { 412 struct health_test_softc *ht; 413 414 ht = &healthtest[event->he_source]; 415 416 /* 417 * Was on-demand testing requested? Restart the state machine if so, 418 * restarting the startup tests. 419 */ 420 if (atomic_load_bool(&ht->ondemand)) { 421 atomic_store_bool(&ht->ondemand, false); 422 ht->ht_state = INIT; 423 } 424 425 switch (ht->ht_state) { 426 case __predict_false(INIT): 427 /* Store the first sample and initialize test state. */ 428 random_healthtest_rct_init(ht, event); 429 random_healthtest_apt_init(ht, event); 430 ht->ht_total_samples = 0; 431 ht->ht_state = STARTUP; 432 return (false); 433 case DISABLED: 434 /* No health testing for this source. */ 435 return (true); 436 case STEADY: 437 case STARTUP: 438 ht->ht_total_samples++; 439 if (random_healthtest_rct_next(ht, event) && 440 random_healthtest_apt_next(ht, event)) { 441 if (ht->ht_state == STARTUP && 442 ht->ht_total_samples >= 443 RANDOM_SELFTEST_STARTUP_SAMPLES) { 444 printf( 445 "random: health test passed for source %s\n", 446 random_source_descr[event->he_source]); 447 ht->ht_state = STEADY; 448 } 449 return (ht->ht_state == STEADY); 450 } 451 ht->ht_state = FAILED; 452 printf( 453 "random: health test failed for source %s, discarding samples\n", 454 random_source_descr[event->he_source]); 455 /* FALLTHROUGH */ 456 case FAILED: 457 return (false); 458 } 459 } 460 461 static bool nist_healthtest_enabled = false; 462 SYSCTL_BOOL(_kern_random, OID_AUTO, nist_healthtest_enabled, 463 CTLFLAG_RDTUN, &nist_healthtest_enabled, 0, 464 "Enable NIST SP 800-90B health tests for noise sources"); 465 466 static void 467 random_healthtest_init(enum random_entropy_source source) 468 { 469 struct health_test_softc *ht; 470 471 ht = &healthtest[source]; 472 KASSERT(ht->ht_state == INIT, 473 ("%s: health test state is %d for source %d", 474 __func__, ht->ht_state, source)); 475 476 /* 477 * If health-testing is enabled, validate all sources except CACHED and 478 * VMGENID: they are deterministic sources used only a small, fixed 479 * number of times, so statistical testing is not applicable. 480 */ 481 if (!nist_healthtest_enabled || 482 source == RANDOM_CACHED || source == RANDOM_PURE_VMGENID) { 483 ht->ht_state = DISABLED; 484 return; 485 } 486 487 /* 488 * Set cutoff values for the two tests, assuming that each sample has 489 * min-entropy of 1 bit and allowing for an error rate of 1 in 2^{34}. 490 * With a sample rate of RANDOM_KTHREAD_HZ, we expect to see an false 491 * positive once in ~54.5 years. 492 * 493 * The RCT limit comes from the formula in section 4.4.1. 494 * 495 * The APT cutoff is calculated using the formula in section 4.4.2 496 * footnote 10 with the window size changed from 512 to 511, since the 497 * test as written counts the number of samples equal to the first 498 * sample in the window, and thus tests W-1 samples. 499 */ 500 ht->ht_rct_limit = 35; 501 ht->ht_apt_cutoff = 330; 502 } 503 504 static int 505 random_healthtest_ondemand(SYSCTL_HANDLER_ARGS) 506 { 507 u_int mask, source; 508 int error; 509 510 mask = 0; 511 error = sysctl_handle_int(oidp, &mask, 0, req); 512 if (error != 0 || req->newptr == NULL) 513 return (error); 514 515 while (mask != 0) { 516 source = ffs(mask) - 1; 517 if (source < nitems(healthtest)) 518 atomic_store_bool(&healthtest[source].ondemand, true); 519 mask &= ~(1u << source); 520 } 521 return (0); 522 } 523 SYSCTL_PROC(_kern_random, OID_AUTO, nist_healthtest_ondemand, 524 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0, 525 random_healthtest_ondemand, "I", 526 "Re-run NIST SP 800-90B startup health tests for a noise source"); 527 528 static int 529 random_check_uint_harvestmask(SYSCTL_HANDLER_ARGS) 530 { 531 static const u_int user_immutable_mask = 532 (((1 << ENTROPYSOURCE) - 1) & (-1UL << RANDOM_PURE_START)) | 533 _RANDOM_HARVEST_ETHER_OFF | _RANDOM_HARVEST_UMA_OFF; 534 535 int error; 536 u_int value, orig_value; 537 538 orig_value = value = hc_source_mask; 539 error = sysctl_handle_int(oidp, &value, 0, req); 540 if (error != 0 || req->newptr == NULL) 541 return (error); 542 543 if (flsl(value) > ENTROPYSOURCE) 544 return (EINVAL); 545 546 /* 547 * Disallow userspace modification of pure entropy sources. 548 */ 549 hc_source_mask = (value & ~user_immutable_mask) | 550 (orig_value & user_immutable_mask); 551 return (0); 552 } 553 SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask, 554 CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0, 555 random_check_uint_harvestmask, "IU", 556 "Entropy harvesting mask"); 557 558 static int 559 random_print_harvestmask(SYSCTL_HANDLER_ARGS) 560 { 561 struct sbuf sbuf; 562 int error, i; 563 564 error = sysctl_wire_old_buffer(req, 0); 565 if (error == 0) { 566 sbuf_new_for_sysctl(&sbuf, NULL, 128, req); 567 for (i = ENTROPYSOURCE - 1; i >= 0; i--) 568 sbuf_cat(&sbuf, (hc_source_mask & (1 << i)) ? "1" : "0"); 569 error = sbuf_finish(&sbuf); 570 sbuf_delete(&sbuf); 571 } 572 return (error); 573 } 574 SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask_bin, 575 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, 576 random_print_harvestmask, "A", 577 "Entropy harvesting mask (printable)"); 578 579 static const char *random_source_descr[ENTROPYSOURCE] = { 580 [RANDOM_CACHED] = "CACHED", 581 [RANDOM_ATTACH] = "ATTACH", 582 [RANDOM_KEYBOARD] = "KEYBOARD", 583 [RANDOM_MOUSE] = "MOUSE", 584 [RANDOM_NET_TUN] = "NET_TUN", 585 [RANDOM_NET_ETHER] = "NET_ETHER", 586 [RANDOM_NET_NG] = "NET_NG", 587 [RANDOM_INTERRUPT] = "INTERRUPT", 588 [RANDOM_SWI] = "SWI", 589 [RANDOM_FS_ATIME] = "FS_ATIME", 590 [RANDOM_UMA] = "UMA", 591 [RANDOM_CALLOUT] = "CALLOUT", 592 [RANDOM_RANDOMDEV] = "RANDOMDEV", /* ENVIRONMENTAL_END */ 593 [RANDOM_PURE_OCTEON] = "PURE_OCTEON", /* PURE_START */ 594 [RANDOM_PURE_SAFE] = "PURE_SAFE", 595 [RANDOM_PURE_GLXSB] = "PURE_GLXSB", 596 [RANDOM_PURE_HIFN] = "PURE_HIFN", 597 [RANDOM_PURE_RDRAND] = "PURE_RDRAND", 598 [RANDOM_PURE_NEHEMIAH] = "PURE_NEHEMIAH", 599 [RANDOM_PURE_RNDTEST] = "PURE_RNDTEST", 600 [RANDOM_PURE_VIRTIO] = "PURE_VIRTIO", 601 [RANDOM_PURE_BROADCOM] = "PURE_BROADCOM", 602 [RANDOM_PURE_CCP] = "PURE_CCP", 603 [RANDOM_PURE_DARN] = "PURE_DARN", 604 [RANDOM_PURE_TPM] = "PURE_TPM", 605 [RANDOM_PURE_VMGENID] = "PURE_VMGENID", 606 [RANDOM_PURE_QUALCOMM] = "PURE_QUALCOMM", 607 [RANDOM_PURE_ARMV8] = "PURE_ARMV8", 608 [RANDOM_PURE_ARM_TRNG] = "PURE_ARM_TRNG", 609 /* "ENTROPYSOURCE" */ 610 }; 611 612 static int 613 random_print_harvestmask_symbolic(SYSCTL_HANDLER_ARGS) 614 { 615 struct sbuf sbuf; 616 int error, i; 617 bool first; 618 619 first = true; 620 error = sysctl_wire_old_buffer(req, 0); 621 if (error == 0) { 622 sbuf_new_for_sysctl(&sbuf, NULL, 128, req); 623 for (i = ENTROPYSOURCE - 1; i >= 0; i--) { 624 if (i >= RANDOM_PURE_START && 625 (hc_source_mask & (1 << i)) == 0) 626 continue; 627 if (!first) 628 sbuf_cat(&sbuf, ","); 629 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "[" : ""); 630 sbuf_cat(&sbuf, random_source_descr[i]); 631 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "]" : ""); 632 first = false; 633 } 634 error = sbuf_finish(&sbuf); 635 sbuf_delete(&sbuf); 636 } 637 return (error); 638 } 639 SYSCTL_PROC(_kern_random_harvest, OID_AUTO, mask_symbolic, 640 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, 641 random_print_harvestmask_symbolic, "A", 642 "Entropy harvesting mask (symbolic)"); 643 644 static void 645 random_harvestq_init(void *unused __unused) 646 { 647 static const u_int almost_everything_mask = 648 (((1 << (RANDOM_ENVIRONMENTAL_END + 1)) - 1) & 649 ~_RANDOM_HARVEST_ETHER_OFF & ~_RANDOM_HARVEST_UMA_OFF); 650 651 hc_source_mask = almost_everything_mask; 652 RANDOM_HARVEST_INIT_LOCK(); 653 harvest_context.hc_active_buf = 0; 654 655 for (int i = 0; i < ENTROPYSOURCE; i++) 656 random_healthtest_init(i); 657 } 658 SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_THIRD, random_harvestq_init, NULL); 659 660 /* 661 * Subroutine to slice up a contiguous chunk of 'entropy' and feed it into the 662 * underlying algorithm. Returns number of bytes actually fed into underlying 663 * algorithm. 664 */ 665 static size_t 666 random_early_prime(char *entropy, size_t len) 667 { 668 struct harvest_event event; 669 size_t i; 670 671 len = rounddown(len, sizeof(event.he_entropy)); 672 if (len == 0) 673 return (0); 674 675 for (i = 0; i < len; i += sizeof(event.he_entropy)) { 676 event.he_somecounter = random_get_cyclecount(); 677 event.he_size = sizeof(event.he_entropy); 678 event.he_source = RANDOM_CACHED; 679 event.he_destination = 680 harvest_context.hc_destination[RANDOM_CACHED]++; 681 memcpy(event.he_entropy, entropy + i, sizeof(event.he_entropy)); 682 random_harvestq_fast_process_event(&event); 683 } 684 explicit_bzero(entropy, len); 685 return (len); 686 } 687 688 /* 689 * Subroutine to search for known loader-loaded files in memory and feed them 690 * into the underlying algorithm early in boot. Returns the number of bytes 691 * loaded (zero if none were loaded). 692 */ 693 static size_t 694 random_prime_loader_file(const char *type) 695 { 696 uint8_t *keyfile, *data; 697 size_t size; 698 699 keyfile = preload_search_by_type(type); 700 if (keyfile == NULL) 701 return (0); 702 703 data = preload_fetch_addr(keyfile); 704 size = preload_fetch_size(keyfile); 705 if (data == NULL) 706 return (0); 707 708 return (random_early_prime(data, size)); 709 } 710 711 /* 712 * This is used to prime the RNG by grabbing any early random stuff 713 * known to the kernel, and inserting it directly into the hashing 714 * module, currently Fortuna. 715 */ 716 static void 717 random_harvestq_prime(void *unused __unused) 718 { 719 size_t size; 720 721 /* 722 * Get entropy that may have been preloaded by loader(8) 723 * and use it to pre-charge the entropy harvest queue. 724 */ 725 size = random_prime_loader_file(RANDOM_CACHED_BOOT_ENTROPY_MODULE); 726 if (bootverbose) { 727 if (size > 0) 728 printf("random: read %zu bytes from preloaded cache\n", 729 size); 730 else 731 printf("random: no preloaded entropy cache\n"); 732 } 733 size = random_prime_loader_file(RANDOM_PLATFORM_BOOT_ENTROPY_MODULE); 734 if (bootverbose) { 735 if (size > 0) 736 printf("random: read %zu bytes from platform bootloader\n", 737 size); 738 else 739 printf("random: no platform bootloader entropy\n"); 740 } 741 } 742 SYSINIT(random_device_prime, SI_SUB_RANDOM, SI_ORDER_MIDDLE, random_harvestq_prime, NULL); 743 744 static void 745 random_harvestq_deinit(void *unused __unused) 746 { 747 748 /* Command the hash/reseed thread to end and wait for it to finish */ 749 random_kthread_control = 0; 750 while (random_kthread_control >= 0) 751 tsleep(&harvest_context.hc_kthread_proc, 0, "harvqterm", hz/5); 752 } 753 SYSUNINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_THIRD, random_harvestq_deinit, NULL); 754 755 /*- 756 * Entropy harvesting queue routine. 757 * 758 * This is supposed to be fast; do not do anything slow in here! 759 * It is also illegal (and morally reprehensible) to insert any 760 * high-rate data here. "High-rate" is defined as a data source 761 * that is likely to fill up the buffer in much less than 100ms. 762 * This includes the "always-on" sources like the Intel "rdrand" 763 * or the VIA Nehamiah "xstore" sources. 764 */ 765 /* XXXRW: get_cyclecount() is cheap on most modern hardware, where cycle 766 * counters are built in, but on older hardware it will do a real time clock 767 * read which can be quite expensive. 768 */ 769 void 770 random_harvest_queue_(const void *entropy, u_int size, enum random_entropy_source origin) 771 { 772 struct harvest_context *hc; 773 struct entropy_buffer *buf; 774 struct harvest_event *event; 775 776 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, 777 ("%s: origin %d invalid", __func__, origin)); 778 779 hc = &harvest_context; 780 RANDOM_HARVEST_LOCK(); 781 buf = &hc->hc_entropy_buf[hc->hc_active_buf]; 782 if (buf->pos < RANDOM_RING_MAX) { 783 event = &buf->ring[buf->pos++]; 784 event->he_somecounter = random_get_cyclecount(); 785 event->he_source = origin; 786 event->he_destination = hc->hc_destination[origin]++; 787 if (size <= sizeof(event->he_entropy)) { 788 event->he_size = size; 789 memcpy(event->he_entropy, entropy, size); 790 } else { 791 /* Big event, so squash it */ 792 event->he_size = sizeof(event->he_entropy[0]); 793 event->he_entropy[0] = jenkins_hash(entropy, size, (uint32_t)(uintptr_t)event); 794 } 795 } 796 RANDOM_HARVEST_UNLOCK(); 797 } 798 799 /*- 800 * Entropy harvesting fast routine. 801 * 802 * This is supposed to be very fast; do not do anything slow in here! 803 * This is the right place for high-rate harvested data. 804 */ 805 void 806 random_harvest_fast_(const void *entropy, u_int size) 807 { 808 u_int pos; 809 810 pos = harvest_context.hc_entropy_fast_accumulator.pos; 811 harvest_context.hc_entropy_fast_accumulator.buf[pos] ^= 812 jenkins_hash(entropy, size, random_get_cyclecount()); 813 harvest_context.hc_entropy_fast_accumulator.pos = (pos + 1)%RANDOM_ACCUM_MAX; 814 } 815 816 /*- 817 * Entropy harvesting direct routine. 818 * 819 * This is not supposed to be fast, but will only be used during 820 * (e.g.) booting when initial entropy is being gathered. 821 */ 822 void 823 random_harvest_direct_(const void *entropy, u_int size, enum random_entropy_source origin) 824 { 825 struct harvest_event event; 826 827 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin)); 828 size = MIN(size, sizeof(event.he_entropy)); 829 event.he_somecounter = random_get_cyclecount(); 830 event.he_size = size; 831 event.he_source = origin; 832 event.he_destination = harvest_context.hc_destination[origin]++; 833 memcpy(event.he_entropy, entropy, size); 834 random_harvestq_fast_process_event(&event); 835 } 836 837 void 838 random_harvest_register_source(enum random_entropy_source source) 839 { 840 841 hc_source_mask |= (1 << source); 842 } 843 844 void 845 random_harvest_deregister_source(enum random_entropy_source source) 846 { 847 848 hc_source_mask &= ~(1 << source); 849 } 850 851 void 852 random_source_register(struct random_source *rsource) 853 { 854 struct random_sources *rrs; 855 856 KASSERT(rsource != NULL, ("invalid input to %s", __func__)); 857 858 rrs = malloc(sizeof(*rrs), M_ENTROPY, M_WAITOK); 859 rrs->rrs_source = rsource; 860 861 random_harvest_register_source(rsource->rs_source); 862 863 printf("random: registering fast source %s\n", rsource->rs_ident); 864 865 RANDOM_HARVEST_LOCK(); 866 CK_LIST_INSERT_HEAD(&source_list, rrs, rrs_entries); 867 RANDOM_HARVEST_UNLOCK(); 868 } 869 870 void 871 random_source_deregister(struct random_source *rsource) 872 { 873 struct random_sources *rrs = NULL; 874 875 KASSERT(rsource != NULL, ("invalid input to %s", __func__)); 876 877 random_harvest_deregister_source(rsource->rs_source); 878 879 RANDOM_HARVEST_LOCK(); 880 CK_LIST_FOREACH(rrs, &source_list, rrs_entries) 881 if (rrs->rrs_source == rsource) { 882 CK_LIST_REMOVE(rrs, rrs_entries); 883 break; 884 } 885 RANDOM_HARVEST_UNLOCK(); 886 887 if (rrs != NULL && epoch_inited) 888 epoch_wait_preempt(rs_epoch); 889 free(rrs, M_ENTROPY); 890 } 891 892 static int 893 random_source_handler(SYSCTL_HANDLER_ARGS) 894 { 895 struct epoch_tracker et; 896 struct random_sources *rrs; 897 struct sbuf sbuf; 898 int error, count; 899 900 error = sysctl_wire_old_buffer(req, 0); 901 if (error != 0) 902 return (error); 903 904 sbuf_new_for_sysctl(&sbuf, NULL, 64, req); 905 count = 0; 906 epoch_enter_preempt(rs_epoch, &et); 907 CK_LIST_FOREACH(rrs, &source_list, rrs_entries) { 908 sbuf_cat(&sbuf, (count++ ? ",'" : "'")); 909 sbuf_cat(&sbuf, rrs->rrs_source->rs_ident); 910 sbuf_cat(&sbuf, "'"); 911 } 912 epoch_exit_preempt(rs_epoch, &et); 913 error = sbuf_finish(&sbuf); 914 sbuf_delete(&sbuf); 915 return (error); 916 } 917 SYSCTL_PROC(_kern_random, OID_AUTO, random_sources, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, 918 NULL, 0, random_source_handler, "A", 919 "List of active fast entropy sources."); 920 921 MODULE_VERSION(random_harvestq, 1); 922