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 static void random_kthread(void); 68 static void random_sources_feed(void); 69 70 static u_int read_rate; 71 72 /* List for the dynamic sysctls */ 73 static struct sysctl_ctx_list random_clist; 74 75 /* 76 * How many events to queue up. We create this many items in 77 * an 'empty' queue, then transfer them to the 'harvest' queue with 78 * supplied junk. When used, they are transferred back to the 79 * 'empty' queue. 80 */ 81 #define RANDOM_RING_MAX 1024 82 #define RANDOM_ACCUM_MAX 8 83 84 /* 1 to let the kernel thread run, 0 to terminate, -1 to mark completion */ 85 volatile int random_kthread_control; 86 87 88 /* Allow the sysadmin to select the broad category of 89 * entropy types to harvest. 90 */ 91 __read_frequently u_int hc_source_mask; 92 93 /* 94 * Put all the harvest queue context stuff in one place. 95 * this make is a bit easier to lock and protect. 96 */ 97 static struct harvest_context { 98 /* The harvest mutex protects all of harvest_context and 99 * the related data. 100 */ 101 struct mtx hc_mtx; 102 /* Round-robin destination cache. */ 103 u_int hc_destination[ENTROPYSOURCE]; 104 /* The context of the kernel thread processing harvested entropy */ 105 struct proc *hc_kthread_proc; 106 /* 107 * Lockless ring buffer holding entropy events 108 * If ring.in == ring.out, 109 * the buffer is empty. 110 * If ring.in != ring.out, 111 * the buffer contains harvested entropy. 112 * If (ring.in + 1) == ring.out (mod RANDOM_RING_MAX), 113 * the buffer is full. 114 * 115 * NOTE: ring.in points to the last added element, 116 * and ring.out points to the last consumed element. 117 * 118 * The ring.in variable needs locking as there are multiple 119 * sources to the ring. Only the sources may change ring.in, 120 * but the consumer may examine it. 121 * 122 * The ring.out variable does not need locking as there is 123 * only one consumer. Only the consumer may change ring.out, 124 * but the sources may examine it. 125 */ 126 struct entropy_ring { 127 struct harvest_event ring[RANDOM_RING_MAX]; 128 volatile u_int in; 129 volatile u_int out; 130 } hc_entropy_ring; 131 struct fast_entropy_accumulator { 132 volatile u_int pos; 133 uint32_t buf[RANDOM_ACCUM_MAX]; 134 } hc_entropy_fast_accumulator; 135 } harvest_context; 136 137 static struct kproc_desc random_proc_kp = { 138 "rand_harvestq", 139 random_kthread, 140 &harvest_context.hc_kthread_proc, 141 }; 142 143 /* Pass the given event straight through to Fortuna/Whatever. */ 144 static __inline void 145 random_harvestq_fast_process_event(struct harvest_event *event) 146 { 147 #if defined(RANDOM_LOADABLE) 148 RANDOM_CONFIG_S_LOCK(); 149 if (p_random_alg_context) 150 #endif 151 p_random_alg_context->ra_event_processor(event); 152 #if defined(RANDOM_LOADABLE) 153 RANDOM_CONFIG_S_UNLOCK(); 154 #endif 155 } 156 157 static void 158 random_kthread(void) 159 { 160 u_int maxloop, ring_out, i; 161 162 /* 163 * Locking is not needed as this is the only place we modify ring.out, and 164 * we only examine ring.in without changing it. Both of these are volatile, 165 * and this is a unique thread. 166 */ 167 for (random_kthread_control = 1; random_kthread_control;) { 168 /* Deal with events, if any. Restrict the number we do in one go. */ 169 maxloop = RANDOM_RING_MAX; 170 while (harvest_context.hc_entropy_ring.out != harvest_context.hc_entropy_ring.in) { 171 ring_out = (harvest_context.hc_entropy_ring.out + 1)%RANDOM_RING_MAX; 172 random_harvestq_fast_process_event(harvest_context.hc_entropy_ring.ring + ring_out); 173 harvest_context.hc_entropy_ring.out = ring_out; 174 if (!--maxloop) 175 break; 176 } 177 random_sources_feed(); 178 /* XXX: FIX!! Increase the high-performance data rate? Need some measurements first. */ 179 for (i = 0; i < RANDOM_ACCUM_MAX; i++) { 180 if (harvest_context.hc_entropy_fast_accumulator.buf[i]) { 181 random_harvest_direct(harvest_context.hc_entropy_fast_accumulator.buf + i, sizeof(harvest_context.hc_entropy_fast_accumulator.buf[0]), RANDOM_UMA); 182 harvest_context.hc_entropy_fast_accumulator.buf[i] = 0; 183 } 184 } 185 /* XXX: FIX!! This is a *great* place to pass hardware/live entropy to random(9) */ 186 tsleep_sbt(&harvest_context.hc_kthread_proc, 0, "-", SBT_1S/10, 0, C_PREL(1)); 187 } 188 random_kthread_control = -1; 189 wakeup(&harvest_context.hc_kthread_proc); 190 kproc_exit(0); 191 /* NOTREACHED */ 192 } 193 /* This happens well after SI_SUB_RANDOM */ 194 SYSINIT(random_device_h_proc, SI_SUB_KICK_SCHEDULER, SI_ORDER_ANY, kproc_start, 195 &random_proc_kp); 196 197 /* 198 * Run through all fast sources reading entropy for the given 199 * number of rounds, which should be a multiple of the number 200 * of entropy accumulation pools in use; it is 32 for Fortuna. 201 */ 202 static void 203 random_sources_feed(void) 204 { 205 uint32_t entropy[HARVESTSIZE]; 206 struct random_sources *rrs; 207 u_int i, n, local_read_rate; 208 209 /* 210 * Step over all of live entropy sources, and feed their output 211 * to the system-wide RNG. 212 */ 213 #if defined(RANDOM_LOADABLE) 214 RANDOM_CONFIG_S_LOCK(); 215 if (p_random_alg_context) { 216 /* It's an indenting error. Yeah, Yeah. */ 217 #endif 218 local_read_rate = atomic_readandclear_32(&read_rate); 219 /* Perform at least one read per round */ 220 local_read_rate = MAX(local_read_rate, 1); 221 /* But not exceeding RANDOM_KEYSIZE_WORDS */ 222 local_read_rate = MIN(local_read_rate, RANDOM_KEYSIZE_WORDS); 223 LIST_FOREACH(rrs, &source_list, rrs_entries) { 224 for (i = 0; i < p_random_alg_context->ra_poolcount*local_read_rate; i++) { 225 n = rrs->rrs_source->rs_read(entropy, sizeof(entropy)); 226 KASSERT((n <= sizeof(entropy)), ("%s: rs_read returned too much data (%u > %zu)", __func__, n, sizeof(entropy))); 227 /* It would appear that in some circumstances (e.g. virtualisation), 228 * the underlying hardware entropy source might not always return 229 * random numbers. Accept this but make a noise. If too much happens, 230 * can that source be trusted? 231 */ 232 if (n == 0) { 233 printf("%s: rs_read for hardware device '%s' returned no entropy.\n", __func__, rrs->rrs_source->rs_ident); 234 continue; 235 } 236 random_harvest_direct(entropy, n, rrs->rrs_source->rs_source); 237 } 238 } 239 explicit_bzero(entropy, sizeof(entropy)); 240 #if defined(RANDOM_LOADABLE) 241 } 242 RANDOM_CONFIG_S_UNLOCK(); 243 #endif 244 } 245 246 void 247 read_rate_increment(u_int chunk) 248 { 249 250 atomic_add_32(&read_rate, chunk); 251 } 252 253 /* ARGSUSED */ 254 static int 255 random_check_uint_harvestmask(SYSCTL_HANDLER_ARGS) 256 { 257 int error; 258 u_int value, orig_value; 259 260 orig_value = value = hc_source_mask; 261 error = sysctl_handle_int(oidp, &value, 0, req); 262 if (error != 0 || req->newptr == NULL) 263 return (error); 264 265 if (flsl(value) > ENTROPYSOURCE) 266 return (EINVAL); 267 268 /* 269 * Disallow userspace modification of pure entropy sources. 270 */ 271 hc_source_mask = (value & ~RANDOM_HARVEST_PURE_MASK) | 272 (orig_value & RANDOM_HARVEST_PURE_MASK); 273 return (0); 274 } 275 276 /* ARGSUSED */ 277 static int 278 random_print_harvestmask(SYSCTL_HANDLER_ARGS) 279 { 280 struct sbuf sbuf; 281 int error, i; 282 283 error = sysctl_wire_old_buffer(req, 0); 284 if (error == 0) { 285 sbuf_new_for_sysctl(&sbuf, NULL, 128, req); 286 for (i = ENTROPYSOURCE - 1; i >= 0; i--) 287 sbuf_cat(&sbuf, (hc_source_mask & (1 << i)) ? "1" : "0"); 288 error = sbuf_finish(&sbuf); 289 sbuf_delete(&sbuf); 290 } 291 return (error); 292 } 293 294 static const char *random_source_descr[ENTROPYSOURCE] = { 295 [RANDOM_CACHED] = "CACHED", 296 [RANDOM_ATTACH] = "ATTACH", 297 [RANDOM_KEYBOARD] = "KEYBOARD", 298 [RANDOM_MOUSE] = "MOUSE", 299 [RANDOM_NET_TUN] = "NET_TUN", 300 [RANDOM_NET_ETHER] = "NET_ETHER", 301 [RANDOM_NET_NG] = "NET_NG", 302 [RANDOM_INTERRUPT] = "INTERRUPT", 303 [RANDOM_SWI] = "SWI", 304 [RANDOM_FS_ATIME] = "FS_ATIME", 305 [RANDOM_UMA] = "UMA", /* ENVIRONMENTAL_END */ 306 [RANDOM_PURE_OCTEON] = "PURE_OCTEON", /* PURE_START */ 307 [RANDOM_PURE_SAFE] = "PURE_SAFE", 308 [RANDOM_PURE_GLXSB] = "PURE_GLXSB", 309 [RANDOM_PURE_UBSEC] = "PURE_UBSEC", 310 [RANDOM_PURE_HIFN] = "PURE_HIFN", 311 [RANDOM_PURE_RDRAND] = "PURE_RDRAND", 312 [RANDOM_PURE_NEHEMIAH] = "PURE_NEHEMIAH", 313 [RANDOM_PURE_RNDTEST] = "PURE_RNDTEST", 314 [RANDOM_PURE_VIRTIO] = "PURE_VIRTIO", 315 [RANDOM_PURE_BROADCOM] = "PURE_BROADCOM", 316 [RANDOM_PURE_CCP] = "PURE_CCP", 317 [RANDOM_PURE_DARN] = "PURE_DARN", 318 /* "ENTROPYSOURCE" */ 319 }; 320 321 /* ARGSUSED */ 322 static int 323 random_print_harvestmask_symbolic(SYSCTL_HANDLER_ARGS) 324 { 325 struct sbuf sbuf; 326 int error, i; 327 bool first; 328 329 first = true; 330 error = sysctl_wire_old_buffer(req, 0); 331 if (error == 0) { 332 sbuf_new_for_sysctl(&sbuf, NULL, 128, req); 333 for (i = ENTROPYSOURCE - 1; i >= 0; i--) { 334 if (i >= RANDOM_PURE_START && 335 (hc_source_mask & (1 << i)) == 0) 336 continue; 337 if (!first) 338 sbuf_cat(&sbuf, ","); 339 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "[" : ""); 340 sbuf_cat(&sbuf, random_source_descr[i]); 341 sbuf_cat(&sbuf, !(hc_source_mask & (1 << i)) ? "]" : ""); 342 first = false; 343 } 344 error = sbuf_finish(&sbuf); 345 sbuf_delete(&sbuf); 346 } 347 return (error); 348 } 349 350 /* ARGSUSED */ 351 static void 352 random_harvestq_init(void *unused __unused) 353 { 354 struct sysctl_oid *random_sys_o; 355 356 random_sys_o = SYSCTL_ADD_NODE(&random_clist, 357 SYSCTL_STATIC_CHILDREN(_kern_random), 358 OID_AUTO, "harvest", CTLFLAG_RW, 0, 359 "Entropy Device Parameters"); 360 hc_source_mask = RANDOM_HARVEST_EVERYTHING_MASK; 361 SYSCTL_ADD_PROC(&random_clist, 362 SYSCTL_CHILDREN(random_sys_o), 363 OID_AUTO, "mask", CTLTYPE_UINT | CTLFLAG_RW, 364 NULL, 0, random_check_uint_harvestmask, "IU", 365 "Entropy harvesting mask"); 366 SYSCTL_ADD_PROC(&random_clist, 367 SYSCTL_CHILDREN(random_sys_o), 368 OID_AUTO, "mask_bin", CTLTYPE_STRING | CTLFLAG_RD, 369 NULL, 0, random_print_harvestmask, "A", "Entropy harvesting mask (printable)"); 370 SYSCTL_ADD_PROC(&random_clist, 371 SYSCTL_CHILDREN(random_sys_o), 372 OID_AUTO, "mask_symbolic", CTLTYPE_STRING | CTLFLAG_RD, 373 NULL, 0, random_print_harvestmask_symbolic, "A", "Entropy harvesting mask (symbolic)"); 374 RANDOM_HARVEST_INIT_LOCK(); 375 harvest_context.hc_entropy_ring.in = harvest_context.hc_entropy_ring.out = 0; 376 } 377 SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_SECOND, random_harvestq_init, NULL); 378 379 /* 380 * This is used to prime the RNG by grabbing any early random stuff 381 * known to the kernel, and inserting it directly into the hashing 382 * module, currently Fortuna. 383 */ 384 /* ARGSUSED */ 385 static void 386 random_harvestq_prime(void *unused __unused) 387 { 388 struct harvest_event event; 389 size_t count, size, i; 390 uint8_t *keyfile, *data; 391 392 /* 393 * Get entropy that may have been preloaded by loader(8) 394 * and use it to pre-charge the entropy harvest queue. 395 */ 396 keyfile = preload_search_by_type(RANDOM_CACHED_BOOT_ENTROPY_MODULE); 397 #ifndef NO_BACKWARD_COMPATIBILITY 398 if (keyfile == NULL) 399 keyfile = preload_search_by_type(RANDOM_LEGACY_BOOT_ENTROPY_MODULE); 400 #endif 401 if (keyfile != NULL) { 402 data = preload_fetch_addr(keyfile); 403 size = preload_fetch_size(keyfile); 404 /* skip the first bit of the stash so others like arc4 can also have some. */ 405 if (size > RANDOM_CACHED_SKIP_START) { 406 data += RANDOM_CACHED_SKIP_START; 407 size -= RANDOM_CACHED_SKIP_START; 408 } 409 /* Trim the size. If the admin has a file with a funny size, we lose some. Tough. */ 410 size -= (size % sizeof(event.he_entropy)); 411 if (data != NULL && size != 0) { 412 for (i = 0; i < size; i += sizeof(event.he_entropy)) { 413 count = sizeof(event.he_entropy); 414 event.he_somecounter = (uint32_t)get_cyclecount(); 415 event.he_size = count; 416 event.he_source = RANDOM_CACHED; 417 event.he_destination = harvest_context.hc_destination[0]++; 418 memcpy(event.he_entropy, data + i, sizeof(event.he_entropy)); 419 random_harvestq_fast_process_event(&event); 420 explicit_bzero(&event, sizeof(event)); 421 } 422 explicit_bzero(data, size); 423 if (bootverbose) 424 printf("random: read %zu bytes from preloaded cache\n", size); 425 } else 426 if (bootverbose) 427 printf("random: no preloaded entropy cache\n"); 428 } 429 } 430 SYSINIT(random_device_prime, SI_SUB_RANDOM, SI_ORDER_FOURTH, random_harvestq_prime, NULL); 431 432 /* ARGSUSED */ 433 static void 434 random_harvestq_deinit(void *unused __unused) 435 { 436 437 /* Command the hash/reseed thread to end and wait for it to finish */ 438 random_kthread_control = 0; 439 while (random_kthread_control >= 0) 440 tsleep(&harvest_context.hc_kthread_proc, 0, "harvqterm", hz/5); 441 sysctl_ctx_free(&random_clist); 442 } 443 SYSUNINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_SECOND, random_harvestq_deinit, NULL); 444 445 /*- 446 * Entropy harvesting queue routine. 447 * 448 * This is supposed to be fast; do not do anything slow in here! 449 * It is also illegal (and morally reprehensible) to insert any 450 * high-rate data here. "High-rate" is defined as a data source 451 * that will usually cause lots of failures of the "Lockless read" 452 * check a few lines below. This includes the "always-on" sources 453 * like the Intel "rdrand" or the VIA Nehamiah "xstore" sources. 454 */ 455 /* XXXRW: get_cyclecount() is cheap on most modern hardware, where cycle 456 * counters are built in, but on older hardware it will do a real time clock 457 * read which can be quite expensive. 458 */ 459 void 460 random_harvest_queue_(const void *entropy, u_int size, enum random_entropy_source origin) 461 { 462 struct harvest_event *event; 463 u_int ring_in; 464 465 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin)); 466 RANDOM_HARVEST_LOCK(); 467 ring_in = (harvest_context.hc_entropy_ring.in + 1)%RANDOM_RING_MAX; 468 if (ring_in != harvest_context.hc_entropy_ring.out) { 469 /* The ring is not full */ 470 event = harvest_context.hc_entropy_ring.ring + ring_in; 471 event->he_somecounter = (uint32_t)get_cyclecount(); 472 event->he_source = origin; 473 event->he_destination = harvest_context.hc_destination[origin]++; 474 if (size <= sizeof(event->he_entropy)) { 475 event->he_size = size; 476 memcpy(event->he_entropy, entropy, size); 477 } 478 else { 479 /* Big event, so squash it */ 480 event->he_size = sizeof(event->he_entropy[0]); 481 event->he_entropy[0] = jenkins_hash(entropy, size, (uint32_t)(uintptr_t)event); 482 } 483 harvest_context.hc_entropy_ring.in = ring_in; 484 } 485 RANDOM_HARVEST_UNLOCK(); 486 } 487 488 /*- 489 * Entropy harvesting fast routine. 490 * 491 * This is supposed to be very fast; do not do anything slow in here! 492 * This is the right place for high-rate harvested data. 493 */ 494 void 495 random_harvest_fast_(const void *entropy, u_int size) 496 { 497 u_int pos; 498 499 pos = harvest_context.hc_entropy_fast_accumulator.pos; 500 harvest_context.hc_entropy_fast_accumulator.buf[pos] ^= jenkins_hash(entropy, size, (uint32_t)get_cyclecount()); 501 harvest_context.hc_entropy_fast_accumulator.pos = (pos + 1)%RANDOM_ACCUM_MAX; 502 } 503 504 /*- 505 * Entropy harvesting direct routine. 506 * 507 * This is not supposed to be fast, but will only be used during 508 * (e.g.) booting when initial entropy is being gathered. 509 */ 510 void 511 random_harvest_direct_(const void *entropy, u_int size, enum random_entropy_source origin) 512 { 513 struct harvest_event event; 514 515 KASSERT(origin >= RANDOM_START && origin < ENTROPYSOURCE, ("%s: origin %d invalid\n", __func__, origin)); 516 size = MIN(size, sizeof(event.he_entropy)); 517 event.he_somecounter = (uint32_t)get_cyclecount(); 518 event.he_size = size; 519 event.he_source = origin; 520 event.he_destination = harvest_context.hc_destination[origin]++; 521 memcpy(event.he_entropy, entropy, size); 522 random_harvestq_fast_process_event(&event); 523 explicit_bzero(&event, sizeof(event)); 524 } 525 526 void 527 random_harvest_register_source(enum random_entropy_source source) 528 { 529 530 hc_source_mask |= (1 << source); 531 } 532 533 void 534 random_harvest_deregister_source(enum random_entropy_source source) 535 { 536 537 hc_source_mask &= ~(1 << source); 538 } 539 540 MODULE_VERSION(random_harvestq, 1); 541