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 __FBSDID("$FreeBSD$"); 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/conf.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 #if defined(RANDOM_LOADABLE) 53 #include <sys/lock.h> 54 #include <sys/sx.h> 55 #endif 56 57 #include <machine/atomic.h> 58 #include <machine/cpu.h> 59 60 #include <crypto/rijndael/rijndael-api-fst.h> 61 #include <crypto/sha2/sha256.h> 62 63 #include <dev/random/hash.h> 64 #include <dev/random/randomdev.h> 65 #include <dev/random/random_harvestq.h> 66 67 #if defined(RANDOM_ENABLE_ETHER) 68 #define _RANDOM_HARVEST_ETHER_OFF 0 69 #else 70 #define _RANDOM_HARVEST_ETHER_OFF (1u << RANDOM_NET_ETHER) 71 #endif 72 #if defined(RANDOM_ENABLE_UMA) 73 #define _RANDOM_HARVEST_UMA_OFF 0 74 #else 75 #define _RANDOM_HARVEST_UMA_OFF (1u << RANDOM_UMA) 76 #endif 77 78 static void random_kthread(void); 79 static void random_sources_feed(void); 80 81 static u_int read_rate; 82 83 /* List for the dynamic sysctls */ 84 static struct sysctl_ctx_list random_clist; 85 86 /* 87 * How many events to queue up. We create this many items in 88 * an 'empty' queue, then transfer them to the 'harvest' queue with 89 * supplied junk. When used, they are transferred back to the 90 * 'empty' queue. 91 */ 92 #define RANDOM_RING_MAX 1024 93 #define RANDOM_ACCUM_MAX 8 94 95 /* 1 to let the kernel thread run, 0 to terminate, -1 to mark completion */ 96 volatile int random_kthread_control; 97 98 99 /* Allow the sysadmin to select the broad category of 100 * entropy types to harvest. 101 */ 102 __read_frequently u_int hc_source_mask; 103 104 /* 105 * Put all the harvest queue context stuff in one place. 106 * this make is a bit easier to lock and protect. 107 */ 108 static struct harvest_context { 109 /* The harvest mutex protects all of harvest_context and 110 * the related data. 111 */ 112 struct mtx hc_mtx; 113 /* Round-robin destination cache. */ 114 u_int hc_destination[ENTROPYSOURCE]; 115 /* The context of the kernel thread processing harvested entropy */ 116 struct proc *hc_kthread_proc; 117 /* 118 * Lockless ring buffer holding entropy events 119 * If ring.in == ring.out, 120 * the buffer is empty. 121 * If ring.in != ring.out, 122 * the buffer contains harvested entropy. 123 * If (ring.in + 1) == ring.out (mod RANDOM_RING_MAX), 124 * the buffer is full. 125 * 126 * NOTE: ring.in points to the last added element, 127 * and ring.out points to the last consumed element. 128 * 129 * The ring.in variable needs locking as there are multiple 130 * sources to the ring. Only the sources may change ring.in, 131 * but the consumer may examine it. 132 * 133 * The ring.out variable does not need locking as there is 134 * only one consumer. Only the consumer may change ring.out, 135 * but the sources may examine it. 136 */ 137 struct entropy_ring { 138 struct harvest_event ring[RANDOM_RING_MAX]; 139 volatile u_int in; 140 volatile u_int out; 141 } hc_entropy_ring; 142 struct fast_entropy_accumulator { 143 volatile u_int pos; 144 uint32_t buf[RANDOM_ACCUM_MAX]; 145 } hc_entropy_fast_accumulator; 146 } harvest_context; 147 148 static struct kproc_desc random_proc_kp = { 149 "rand_harvestq", 150 random_kthread, 151 &harvest_context.hc_kthread_proc, 152 }; 153 154 /* Pass the given event straight through to Fortuna/Whatever. */ 155 static __inline void 156 random_harvestq_fast_process_event(struct harvest_event *event) 157 { 158 #if defined(RANDOM_LOADABLE) 159 RANDOM_CONFIG_S_LOCK(); 160 if (p_random_alg_context) 161 #endif 162 p_random_alg_context->ra_event_processor(event); 163 #if defined(RANDOM_LOADABLE) 164 RANDOM_CONFIG_S_UNLOCK(); 165 #endif 166 } 167 168 static void 169 random_kthread(void) 170 { 171 u_int maxloop, ring_out, i; 172 173 /* 174 * Locking is not needed as this is the only place we modify ring.out, and 175 * we only examine ring.in without changing it. Both of these are volatile, 176 * and this is a unique thread. 177 */ 178 for (random_kthread_control = 1; random_kthread_control;) { 179 /* Deal with events, if any. Restrict the number we do in one go. */ 180 maxloop = RANDOM_RING_MAX; 181 while (harvest_context.hc_entropy_ring.out != harvest_context.hc_entropy_ring.in) { 182 ring_out = (harvest_context.hc_entropy_ring.out + 1)%RANDOM_RING_MAX; 183 random_harvestq_fast_process_event(harvest_context.hc_entropy_ring.ring + ring_out); 184 harvest_context.hc_entropy_ring.out = ring_out; 185 if (!--maxloop) 186 break; 187 } 188 random_sources_feed(); 189 /* XXX: FIX!! Increase the high-performance data rate? Need some measurements first. */ 190 for (i = 0; i < RANDOM_ACCUM_MAX; i++) { 191 if (harvest_context.hc_entropy_fast_accumulator.buf[i]) { 192 random_harvest_direct(harvest_context.hc_entropy_fast_accumulator.buf + i, sizeof(harvest_context.hc_entropy_fast_accumulator.buf[0]), RANDOM_UMA); 193 harvest_context.hc_entropy_fast_accumulator.buf[i] = 0; 194 } 195 } 196 /* XXX: FIX!! This is a *great* place to pass hardware/live entropy to random(9) */ 197 tsleep_sbt(&harvest_context.hc_kthread_proc, 0, "-", SBT_1S/10, 0, C_PREL(1)); 198 } 199 random_kthread_control = -1; 200 wakeup(&harvest_context.hc_kthread_proc); 201 kproc_exit(0); 202 /* NOTREACHED */ 203 } 204 /* This happens well after SI_SUB_RANDOM */ 205 SYSINIT(random_device_h_proc, SI_SUB_KICK_SCHEDULER, SI_ORDER_ANY, kproc_start, 206 &random_proc_kp); 207 208 /* 209 * Run through all fast sources reading entropy for the given 210 * number of rounds, which should be a multiple of the number 211 * of entropy accumulation pools in use; it is 32 for Fortuna. 212 */ 213 static void 214 random_sources_feed(void) 215 { 216 uint32_t entropy[HARVESTSIZE]; 217 struct random_sources *rrs; 218 u_int i, n, local_read_rate; 219 220 /* 221 * Step over all of live entropy sources, and feed their output 222 * to the system-wide RNG. 223 */ 224 #if defined(RANDOM_LOADABLE) 225 RANDOM_CONFIG_S_LOCK(); 226 if (p_random_alg_context) { 227 /* It's an indenting error. Yeah, Yeah. */ 228 #endif 229 local_read_rate = atomic_readandclear_32(&read_rate); 230 /* Perform at least one read per round */ 231 local_read_rate = MAX(local_read_rate, 1); 232 /* But not exceeding RANDOM_KEYSIZE_WORDS */ 233 local_read_rate = MIN(local_read_rate, RANDOM_KEYSIZE_WORDS); 234 LIST_FOREACH(rrs, &source_list, rrs_entries) { 235 for (i = 0; i < p_random_alg_context->ra_poolcount*local_read_rate; i++) { 236 n = rrs->rrs_source->rs_read(entropy, sizeof(entropy)); 237 KASSERT((n <= sizeof(entropy)), ("%s: rs_read returned too much data (%u > %zu)", __func__, n, sizeof(entropy))); 238 /* 239 * Sometimes the HW entropy source doesn't have anything 240 * ready for us. This isn't necessarily untrustworthy. 241 * We don't perform any other verification of an entropy 242 * source (i.e., length is allowed to be anywhere from 1 243 * to sizeof(entropy), quality is unchecked, etc), so 244 * don't balk verbosely at slow random sources either. 245 * There are reports that RDSEED on x86 metal falls 246 * behind the rate at which we query it, for example. 247 * But it's still a better entropy source than RDRAND. 248 */ 249 if (n == 0) 250 continue; 251 random_harvest_direct(entropy, n, rrs->rrs_source->rs_source); 252 } 253 } 254 explicit_bzero(entropy, sizeof(entropy)); 255 #if defined(RANDOM_LOADABLE) 256 } 257 RANDOM_CONFIG_S_UNLOCK(); 258 #endif 259 } 260 261 void 262 read_rate_increment(u_int chunk) 263 { 264 265 atomic_add_32(&read_rate, chunk); 266 } 267 268 /* ARGSUSED */ 269 static int 270 random_check_uint_harvestmask(SYSCTL_HANDLER_ARGS) 271 { 272 static const u_int user_immutable_mask = 273 (((1 << ENTROPYSOURCE) - 1) & (-1UL << RANDOM_PURE_START)) | 274 _RANDOM_HARVEST_ETHER_OFF | _RANDOM_HARVEST_UMA_OFF; 275 276 int error; 277 u_int value, orig_value; 278 279 orig_value = value = hc_source_mask; 280 error = sysctl_handle_int(oidp, &value, 0, req); 281 if (error != 0 || req->newptr == NULL) 282 return (error); 283 284 if (flsl(value) > ENTROPYSOURCE) 285 return (EINVAL); 286 287 /* 288 * Disallow userspace modification of pure entropy sources. 289 */ 290 hc_source_mask = (value & ~user_immutable_mask) | 291 (orig_value & user_immutable_mask); 292 return (0); 293 } 294 295 /* ARGSUSED */ 296 static int 297 random_print_harvestmask(SYSCTL_HANDLER_ARGS) 298 { 299 struct sbuf sbuf; 300 int error, i; 301 302 error = sysctl_wire_old_buffer(req, 0); 303 if (error == 0) { 304 sbuf_new_for_sysctl(&sbuf, NULL, 128, req); 305 for (i = ENTROPYSOURCE - 1; i >= 0; i--) 306 sbuf_cat(&sbuf, (hc_source_mask & (1 << i)) ? "1" : "0"); 307 error = sbuf_finish(&sbuf); 308 sbuf_delete(&sbuf); 309 } 310 return (error); 311 } 312 313 static const char *random_source_descr[ENTROPYSOURCE] = { 314 [RANDOM_CACHED] = "CACHED", 315 [RANDOM_ATTACH] = "ATTACH", 316 [RANDOM_KEYBOARD] = "KEYBOARD", 317 [RANDOM_MOUSE] = "MOUSE", 318 [RANDOM_NET_TUN] = "NET_TUN", 319 [RANDOM_NET_ETHER] = "NET_ETHER", 320 [RANDOM_NET_NG] = "NET_NG", 321 [RANDOM_INTERRUPT] = "INTERRUPT", 322 [RANDOM_SWI] = "SWI", 323 [RANDOM_FS_ATIME] = "FS_ATIME", 324 [RANDOM_UMA] = "UMA", /* ENVIRONMENTAL_END */ 325 [RANDOM_PURE_OCTEON] = "PURE_OCTEON", /* PURE_START */ 326 [RANDOM_PURE_SAFE] = "PURE_SAFE", 327 [RANDOM_PURE_GLXSB] = "PURE_GLXSB", 328 [RANDOM_PURE_UBSEC] = "PURE_UBSEC", 329 [RANDOM_PURE_HIFN] = "PURE_HIFN", 330 [RANDOM_PURE_RDRAND] = "PURE_RDRAND", 331 [RANDOM_PURE_NEHEMIAH] = "PURE_NEHEMIAH", 332 [RANDOM_PURE_RNDTEST] = "PURE_RNDTEST", 333 [RANDOM_PURE_VIRTIO] = "PURE_VIRTIO", 334 [RANDOM_PURE_BROADCOM] = "PURE_BROADCOM", 335 [RANDOM_PURE_CCP] = "PURE_CCP", 336 [RANDOM_PURE_DARN] = "PURE_DARN", 337 [RANDOM_PURE_TPM] = "PURE_TPM", 338 /* "ENTROPYSOURCE" */ 339 }; 340 341 /* ARGSUSED */ 342 static int 343 random_print_harvestmask_symbolic(SYSCTL_HANDLER_ARGS) 344 { 345 struct sbuf sbuf; 346 int error, i; 347 bool first; 348 349 first = true; 350 error = sysctl_wire_old_buffer(req, 0); 351 if (error == 0) { 352 sbuf_new_for_sysctl(&sbuf, NULL, 128, req); 353 for (i = ENTROPYSOURCE - 1; i >= 0; i--) { 354 if (i >= RANDOM_PURE_START && 355 (hc_source_mask & (1 << i)) == 0) 356 continue; 357 if (!first) 358 sbuf_cat(&sbuf, ","); 359 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "[" : ""); 360 sbuf_cat(&sbuf, random_source_descr[i]); 361 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "]" : ""); 362 first = false; 363 } 364 error = sbuf_finish(&sbuf); 365 sbuf_delete(&sbuf); 366 } 367 return (error); 368 } 369 370 /* ARGSUSED */ 371 static void 372 random_harvestq_init(void *unused __unused) 373 { 374 static const u_int almost_everything_mask = 375 (((1 << (RANDOM_ENVIRONMENTAL_END + 1)) - 1) & 376 ~_RANDOM_HARVEST_ETHER_OFF & ~_RANDOM_HARVEST_UMA_OFF); 377 378 struct sysctl_oid *random_sys_o; 379 380 random_sys_o = SYSCTL_ADD_NODE(&random_clist, 381 SYSCTL_STATIC_CHILDREN(_kern_random), 382 OID_AUTO, "harvest", CTLFLAG_RW, 0, 383 "Entropy Device Parameters"); 384 hc_source_mask = almost_everything_mask; 385 SYSCTL_ADD_PROC(&random_clist, 386 SYSCTL_CHILDREN(random_sys_o), 387 OID_AUTO, "mask", CTLTYPE_UINT | CTLFLAG_RW, 388 NULL, 0, random_check_uint_harvestmask, "IU", 389 "Entropy harvesting mask"); 390 SYSCTL_ADD_PROC(&random_clist, 391 SYSCTL_CHILDREN(random_sys_o), 392 OID_AUTO, "mask_bin", CTLTYPE_STRING | CTLFLAG_RD, 393 NULL, 0, random_print_harvestmask, "A", "Entropy harvesting mask (printable)"); 394 SYSCTL_ADD_PROC(&random_clist, 395 SYSCTL_CHILDREN(random_sys_o), 396 OID_AUTO, "mask_symbolic", CTLTYPE_STRING | CTLFLAG_RD, 397 NULL, 0, random_print_harvestmask_symbolic, "A", "Entropy harvesting mask (symbolic)"); 398 RANDOM_HARVEST_INIT_LOCK(); 399 harvest_context.hc_entropy_ring.in = harvest_context.hc_entropy_ring.out = 0; 400 } 401 SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_SECOND, random_harvestq_init, NULL); 402 403 /* 404 * This is used to prime the RNG by grabbing any early random stuff 405 * known to the kernel, and inserting it directly into the hashing 406 * module, currently Fortuna. 407 */ 408 /* ARGSUSED */ 409 static void 410 random_harvestq_prime(void *unused __unused) 411 { 412 struct harvest_event event; 413 size_t count, size, i; 414 uint8_t *keyfile, *data; 415 416 /* 417 * Get entropy that may have been preloaded by loader(8) 418 * and use it to pre-charge the entropy harvest queue. 419 */ 420 keyfile = preload_search_by_type(RANDOM_CACHED_BOOT_ENTROPY_MODULE); 421 #ifndef NO_BACKWARD_COMPATIBILITY 422 if (keyfile == NULL) 423 keyfile = preload_search_by_type(RANDOM_LEGACY_BOOT_ENTROPY_MODULE); 424 #endif 425 if (keyfile != NULL) { 426 data = preload_fetch_addr(keyfile); 427 size = preload_fetch_size(keyfile); 428 /* Trim the size. If the admin has a file with a funny size, we lose some. Tough. */ 429 size -= (size % sizeof(event.he_entropy)); 430 if (data != NULL && size != 0) { 431 for (i = 0; i < size; i += sizeof(event.he_entropy)) { 432 count = sizeof(event.he_entropy); 433 event.he_somecounter = (uint32_t)get_cyclecount(); 434 event.he_size = count; 435 event.he_source = RANDOM_CACHED; 436 event.he_destination = 437 harvest_context.hc_destination[RANDOM_CACHED]++; 438 memcpy(event.he_entropy, data + i, sizeof(event.he_entropy)); 439 random_harvestq_fast_process_event(&event); 440 explicit_bzero(&event, sizeof(event)); 441 } 442 explicit_bzero(data, size); 443 if (bootverbose) 444 printf("random: read %zu bytes from preloaded cache\n", size); 445 } else 446 if (bootverbose) 447 printf("random: no preloaded entropy cache\n"); 448 } 449 } 450 SYSINIT(random_device_prime, SI_SUB_RANDOM, SI_ORDER_FOURTH, random_harvestq_prime, NULL); 451 452 /* ARGSUSED */ 453 static void 454 random_harvestq_deinit(void *unused __unused) 455 { 456 457 /* Command the hash/reseed thread to end and wait for it to finish */ 458 random_kthread_control = 0; 459 while (random_kthread_control >= 0) 460 tsleep(&harvest_context.hc_kthread_proc, 0, "harvqterm", hz/5); 461 sysctl_ctx_free(&random_clist); 462 } 463 SYSUNINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_SECOND, random_harvestq_deinit, NULL); 464 465 /*- 466 * Entropy harvesting queue routine. 467 * 468 * This is supposed to be fast; do not do anything slow in here! 469 * It is also illegal (and morally reprehensible) to insert any 470 * high-rate data here. "High-rate" is defined as a data source 471 * that will usually cause lots of failures of the "Lockless read" 472 * check a few lines below. This includes the "always-on" sources 473 * like the Intel "rdrand" or the VIA Nehamiah "xstore" sources. 474 */ 475 /* XXXRW: get_cyclecount() is cheap on most modern hardware, where cycle 476 * counters are built in, but on older hardware it will do a real time clock 477 * read which can be quite expensive. 478 */ 479 void 480 random_harvest_queue_(const void *entropy, u_int size, enum random_entropy_source origin) 481 { 482 struct harvest_event *event; 483 u_int ring_in; 484 485 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin)); 486 RANDOM_HARVEST_LOCK(); 487 ring_in = (harvest_context.hc_entropy_ring.in + 1)%RANDOM_RING_MAX; 488 if (ring_in != harvest_context.hc_entropy_ring.out) { 489 /* The ring is not full */ 490 event = harvest_context.hc_entropy_ring.ring + ring_in; 491 event->he_somecounter = (uint32_t)get_cyclecount(); 492 event->he_source = origin; 493 event->he_destination = harvest_context.hc_destination[origin]++; 494 if (size <= sizeof(event->he_entropy)) { 495 event->he_size = size; 496 memcpy(event->he_entropy, entropy, size); 497 } 498 else { 499 /* Big event, so squash it */ 500 event->he_size = sizeof(event->he_entropy[0]); 501 event->he_entropy[0] = jenkins_hash(entropy, size, (uint32_t)(uintptr_t)event); 502 } 503 harvest_context.hc_entropy_ring.in = ring_in; 504 } 505 RANDOM_HARVEST_UNLOCK(); 506 } 507 508 /*- 509 * Entropy harvesting fast routine. 510 * 511 * This is supposed to be very fast; do not do anything slow in here! 512 * This is the right place for high-rate harvested data. 513 */ 514 void 515 random_harvest_fast_(const void *entropy, u_int size) 516 { 517 u_int pos; 518 519 pos = harvest_context.hc_entropy_fast_accumulator.pos; 520 harvest_context.hc_entropy_fast_accumulator.buf[pos] ^= jenkins_hash(entropy, size, (uint32_t)get_cyclecount()); 521 harvest_context.hc_entropy_fast_accumulator.pos = (pos + 1)%RANDOM_ACCUM_MAX; 522 } 523 524 /*- 525 * Entropy harvesting direct routine. 526 * 527 * This is not supposed to be fast, but will only be used during 528 * (e.g.) booting when initial entropy is being gathered. 529 */ 530 void 531 random_harvest_direct_(const void *entropy, u_int size, enum random_entropy_source origin) 532 { 533 struct harvest_event event; 534 535 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin)); 536 size = MIN(size, sizeof(event.he_entropy)); 537 event.he_somecounter = (uint32_t)get_cyclecount(); 538 event.he_size = size; 539 event.he_source = origin; 540 event.he_destination = harvest_context.hc_destination[origin]++; 541 memcpy(event.he_entropy, entropy, size); 542 random_harvestq_fast_process_event(&event); 543 explicit_bzero(&event, sizeof(event)); 544 } 545 546 void 547 random_harvest_register_source(enum random_entropy_source source) 548 { 549 550 hc_source_mask |= (1 << source); 551 } 552 553 void 554 random_harvest_deregister_source(enum random_entropy_source source) 555 { 556 557 hc_source_mask &= ~(1 << source); 558 } 559 560 MODULE_VERSION(random_harvestq, 1); 561