1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 /* 22 * Copyright 2010 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* 27 * Software based random number provider for the Kernel Cryptographic 28 * Framework (KCF). This provider periodically collects unpredictable input 29 * from external sources and processes it into a pool of entropy (randomness) 30 * in order to satisfy requests for random bits from kCF. It implements 31 * software-based mixing, extraction, and generation algorithms. 32 * 33 * A history note: The software-based algorithms in this file used to be 34 * part of the /dev/random driver. 35 */ 36 37 #include <sys/types.h> 38 #include <sys/errno.h> 39 #include <sys/debug.h> 40 #include <vm/seg_kmem.h> 41 #include <vm/hat.h> 42 #include <sys/systm.h> 43 #include <sys/memlist.h> 44 #include <sys/cmn_err.h> 45 #include <sys/ksynch.h> 46 #include <sys/random.h> 47 #include <sys/ddi.h> 48 #include <sys/mman.h> 49 #include <sys/sysmacros.h> 50 #include <sys/mem_config.h> 51 #include <sys/time.h> 52 #include <sys/crypto/spi.h> 53 #include <sys/sha1.h> 54 #include <sys/sunddi.h> 55 #include <sys/modctl.h> 56 #include <sys/hold_page.h> 57 #include <rng/fips_random.h> 58 59 #define RNDPOOLSIZE 1024 /* Pool size in bytes */ 60 #define HASHBUFSIZE 64 /* Buffer size used for pool mixing */ 61 #define MAXMEMBLOCKS 16384 /* Number of memory blocks to scan */ 62 #define MEMBLOCKSIZE 4096 /* Size of memory block to read */ 63 #define MINEXTRACTBITS 160 /* Min entropy level for extraction */ 64 #define TIMEOUT_INTERVAL 5 /* Periodic mixing interval in secs */ 65 66 /* Hash-algo generic definitions. For now, they are SHA1's. */ 67 #define HASHSIZE 20 68 #define HASH_CTX SHA1_CTX 69 #define HashInit(ctx) SHA1Init((ctx)) 70 #define HashUpdate(ctx, p, s) SHA1Update((ctx), (p), (s)) 71 #define HashFinal(d, ctx) SHA1Final((d), (ctx)) 72 73 /* Physical memory entropy source */ 74 typedef struct physmem_entsrc_s { 75 uint8_t *parity; /* parity bit vector */ 76 caddr_t pmbuf; /* buffer for memory block */ 77 uint32_t nblocks; /* number of memory blocks */ 78 int entperblock; /* entropy bits per block read */ 79 hrtime_t last_diff; /* previous time to process a block */ 80 hrtime_t last_delta; /* previous time delta */ 81 hrtime_t last_delta2; /* previous 2nd order time delta */ 82 } physmem_entsrc_t; 83 84 static uint32_t srndpool[RNDPOOLSIZE/4]; /* Pool of random bits */ 85 static uint32_t buffer[RNDPOOLSIZE/4]; /* entropy mixed in later */ 86 static int buffer_bytes; /* bytes written to buffer */ 87 static uint32_t entropy_bits; /* pool's current amount of entropy */ 88 static kmutex_t srndpool_lock; /* protects r/w accesses to the pool, */ 89 /* and the global variables */ 90 static kmutex_t buffer_lock; /* protects r/w accesses to buffer */ 91 static kcondvar_t srndpool_read_cv; /* serializes poll/read syscalls */ 92 static int pindex; /* Global index for adding/extracting */ 93 /* from the pool */ 94 static int bstart, bindex; /* Global vars for adding/extracting */ 95 /* from the buffer */ 96 static uint8_t leftover[HASHSIZE]; /* leftover output */ 97 static uint32_t swrand_XKEY[6]; /* one extra word for getentropy */ 98 static int leftover_bytes; /* leftover length */ 99 static uint32_t previous_bytes[HASHSIZE/BYTES_IN_WORD]; /* prev random bytes */ 100 101 static physmem_entsrc_t entsrc; /* Physical mem as an entropy source */ 102 static timeout_id_t rnd_timeout_id; 103 static int snum_waiters; 104 static crypto_kcf_provider_handle_t swrand_prov_handle = NULL; 105 swrand_stats_t swrand_stats; 106 107 static int physmem_ent_init(physmem_entsrc_t *); 108 static void physmem_ent_fini(physmem_entsrc_t *); 109 static void physmem_ent_gen(physmem_entsrc_t *); 110 static int physmem_parity_update(uint8_t *, uint32_t, int); 111 static void physmem_count_blocks(); 112 static void rnd_dr_callback_post_add(void *, pgcnt_t); 113 static int rnd_dr_callback_pre_del(void *, pgcnt_t); 114 static void rnd_dr_callback_post_del(void *, pgcnt_t, int); 115 static void rnd_handler(void *arg); 116 static void swrand_init(); 117 static void swrand_schedule_timeout(void); 118 static int swrand_get_entropy(uint8_t *ptr, size_t len, boolean_t); 119 static void swrand_add_entropy(uint8_t *ptr, size_t len, uint16_t entropy_est); 120 static void swrand_add_entropy_later(uint8_t *ptr, size_t len); 121 122 /* Dynamic Reconfiguration related declarations */ 123 kphysm_setup_vector_t rnd_dr_callback_vec = { 124 KPHYSM_SETUP_VECTOR_VERSION, 125 rnd_dr_callback_post_add, 126 rnd_dr_callback_pre_del, 127 rnd_dr_callback_post_del 128 }; 129 130 extern struct mod_ops mod_cryptoops; 131 132 /* 133 * Module linkage information for the kernel. 134 */ 135 static struct modlcrypto modlcrypto = { 136 &mod_cryptoops, 137 "Kernel Random number Provider" 138 }; 139 140 static struct modlinkage modlinkage = { 141 MODREV_1, 142 (void *)&modlcrypto, 143 NULL 144 }; 145 146 /* 147 * CSPI information (entry points, provider info, etc.) 148 */ 149 static void swrand_provider_status(crypto_provider_handle_t, uint_t *); 150 151 static crypto_control_ops_t swrand_control_ops = { 152 swrand_provider_status 153 }; 154 155 static int swrand_seed_random(crypto_provider_handle_t, crypto_session_id_t, 156 uchar_t *, size_t, uint_t, uint32_t, crypto_req_handle_t); 157 static int swrand_generate_random(crypto_provider_handle_t, 158 crypto_session_id_t, uchar_t *, size_t, crypto_req_handle_t); 159 160 static crypto_random_number_ops_t swrand_random_number_ops = { 161 swrand_seed_random, 162 swrand_generate_random 163 }; 164 165 static void swrand_POST(int *); 166 167 static crypto_fips140_ops_t swrand_fips140_ops = { 168 swrand_POST 169 }; 170 171 static crypto_ops_t swrand_crypto_ops = { 172 &swrand_control_ops, 173 NULL, 174 NULL, 175 NULL, 176 NULL, 177 NULL, 178 NULL, 179 NULL, 180 &swrand_random_number_ops, 181 NULL, 182 NULL, 183 NULL, 184 NULL, 185 NULL, 186 NULL, 187 NULL, 188 &swrand_fips140_ops 189 }; 190 191 static crypto_provider_info_t swrand_prov_info = { 192 CRYPTO_SPI_VERSION_4, 193 "Kernel Random Number Provider", 194 CRYPTO_SW_PROVIDER, 195 {&modlinkage}, 196 NULL, 197 &swrand_crypto_ops, 198 0, 199 NULL 200 }; 201 202 int 203 _init(void) 204 { 205 int ret; 206 hrtime_t ts; 207 time_t now; 208 209 /* 210 * Register with KCF. If the registration fails, return error. 211 */ 212 if ((ret = crypto_register_provider(&swrand_prov_info, 213 &swrand_prov_handle)) != CRYPTO_SUCCESS) { 214 cmn_err(CE_WARN, "swrand : Kernel Random Number Provider " 215 "disabled for /dev/random use"); 216 return (EACCES); 217 } 218 219 mutex_init(&srndpool_lock, NULL, MUTEX_DEFAULT, NULL); 220 mutex_init(&buffer_lock, NULL, MUTEX_DEFAULT, NULL); 221 cv_init(&srndpool_read_cv, NULL, CV_DEFAULT, NULL); 222 entropy_bits = 0; 223 pindex = 0; 224 bindex = 0; 225 bstart = 0; 226 snum_waiters = 0; 227 leftover_bytes = 0; 228 buffer_bytes = 0; 229 230 /* 231 * Initialize the pool using 232 * . 2 unpredictable times: high resolution time since the boot-time, 233 * and the current time-of-the day. 234 * . The initial physical memory state. 235 */ 236 ts = gethrtime(); 237 swrand_add_entropy((uint8_t *)&ts, sizeof (ts), 0); 238 239 (void) drv_getparm(TIME, &now); 240 swrand_add_entropy((uint8_t *)&now, sizeof (now), 0); 241 242 ret = kphysm_setup_func_register(&rnd_dr_callback_vec, NULL); 243 ASSERT(ret == 0); 244 245 if (physmem_ent_init(&entsrc) != 0) { 246 mutex_destroy(&srndpool_lock); 247 mutex_destroy(&buffer_lock); 248 cv_destroy(&srndpool_read_cv); 249 (void) crypto_unregister_provider(swrand_prov_handle); 250 return (ENOMEM); 251 } 252 253 if ((ret = mod_install(&modlinkage)) != 0) { 254 mutex_destroy(&srndpool_lock); 255 mutex_destroy(&buffer_lock); 256 cv_destroy(&srndpool_read_cv); 257 physmem_ent_fini(&entsrc); 258 (void) crypto_unregister_provider(swrand_prov_handle); 259 return (ret); 260 } 261 262 /* Schedule periodic mixing of the pool. */ 263 mutex_enter(&srndpool_lock); 264 swrand_schedule_timeout(); 265 mutex_exit(&srndpool_lock); 266 (void) swrand_get_entropy((uint8_t *)swrand_XKEY, HASHSIZE, B_TRUE); 267 bcopy(swrand_XKEY, previous_bytes, HASHSIZE); 268 269 return (0); 270 } 271 272 int 273 _info(struct modinfo *modinfop) 274 { 275 return (mod_info(&modlinkage, modinfop)); 276 } 277 278 /* 279 * Control entry points. 280 */ 281 /* ARGSUSED */ 282 static void 283 swrand_provider_status(crypto_provider_handle_t provider, uint_t *status) 284 { 285 *status = CRYPTO_PROVIDER_READY; 286 } 287 288 /* 289 * Random number entry points. 290 */ 291 /* ARGSUSED */ 292 static int 293 swrand_seed_random(crypto_provider_handle_t provider, crypto_session_id_t sid, 294 uchar_t *buf, size_t len, uint_t entropy_est, uint32_t flags, 295 crypto_req_handle_t req) 296 { 297 /* The entropy estimate is always 0 in this path */ 298 if (flags & CRYPTO_SEED_NOW) 299 swrand_add_entropy(buf, len, 0); 300 else 301 swrand_add_entropy_later(buf, len); 302 return (CRYPTO_SUCCESS); 303 } 304 305 /* ARGSUSED */ 306 static int 307 swrand_generate_random(crypto_provider_handle_t provider, 308 crypto_session_id_t sid, uchar_t *buf, size_t len, crypto_req_handle_t req) 309 { 310 if (crypto_kmflag(req) == KM_NOSLEEP) 311 (void) swrand_get_entropy(buf, len, B_TRUE); 312 else 313 (void) swrand_get_entropy(buf, len, B_FALSE); 314 315 return (CRYPTO_SUCCESS); 316 } 317 318 /* 319 * Extraction of entropy from the pool. 320 * 321 * Returns "len" random bytes in *ptr. 322 * Try to gather some more entropy by calling physmem_ent_gen() when less than 323 * MINEXTRACTBITS are present in the pool. 324 * Will block if not enough entropy was available and the call is blocking. 325 */ 326 static int 327 swrand_get_entropy(uint8_t *ptr, size_t len, boolean_t nonblock) 328 { 329 int i, bytes; 330 HASH_CTX hashctx; 331 uint8_t digest[HASHSIZE], *pool; 332 uint32_t tempout[HASHSIZE/BYTES_IN_WORD]; 333 int size; 334 335 mutex_enter(&srndpool_lock); 336 if (leftover_bytes > 0) { 337 bytes = min(len, leftover_bytes); 338 bcopy(leftover, ptr, bytes); 339 len -= bytes; 340 ptr += bytes; 341 leftover_bytes -= bytes; 342 if (leftover_bytes > 0) 343 ovbcopy(leftover+bytes, leftover, leftover_bytes); 344 } 345 346 while (len > 0) { 347 /* Check if there is enough entropy */ 348 while (entropy_bits < MINEXTRACTBITS) { 349 350 physmem_ent_gen(&entsrc); 351 352 if (entropy_bits < MINEXTRACTBITS && 353 nonblock == B_TRUE) { 354 mutex_exit(&srndpool_lock); 355 return (EAGAIN); 356 } 357 358 if (entropy_bits < MINEXTRACTBITS) { 359 ASSERT(nonblock == B_FALSE); 360 snum_waiters++; 361 if (cv_wait_sig(&srndpool_read_cv, 362 &srndpool_lock) == 0) { 363 snum_waiters--; 364 mutex_exit(&srndpool_lock); 365 return (EINTR); 366 } 367 snum_waiters--; 368 } 369 } 370 371 /* Figure out how many bytes to extract */ 372 bytes = min(HASHSIZE, len); 373 bytes = min(bytes, CRYPTO_BITS2BYTES(entropy_bits)); 374 entropy_bits -= CRYPTO_BYTES2BITS(bytes); 375 BUMP_SWRAND_STATS(ss_entOut, CRYPTO_BYTES2BITS(bytes)); 376 swrand_stats.ss_entEst = entropy_bits; 377 378 /* Extract entropy by hashing pool content */ 379 HashInit(&hashctx); 380 HashUpdate(&hashctx, (uint8_t *)srndpool, RNDPOOLSIZE); 381 HashFinal(digest, &hashctx); 382 383 /* 384 * Feed the digest back into the pool so next 385 * extraction produces different result 386 */ 387 pool = (uint8_t *)srndpool; 388 for (i = 0; i < HASHSIZE; i++) { 389 pool[pindex++] ^= digest[i]; 390 /* pindex modulo RNDPOOLSIZE */ 391 pindex &= (RNDPOOLSIZE - 1); 392 } 393 394 /* LINTED E_BAD_PTR_CAST_ALIGN */ 395 fips_random_inner(swrand_XKEY, tempout, (uint32_t *)digest); 396 397 if (len >= HASHSIZE) { 398 size = HASHSIZE; 399 } else { 400 size = min(bytes, HASHSIZE); 401 } 402 403 /* 404 * FIPS 140-2: Continuous RNG test - each generation 405 * of an n-bit block shall be compared with the previously 406 * generated block. Test shall fail if any two compared 407 * n-bit blocks are equal. 408 */ 409 for (i = 0; i < HASHSIZE/BYTES_IN_WORD; i++) { 410 if (tempout[i] != previous_bytes[i]) 411 break; 412 } 413 414 if (i == HASHSIZE/BYTES_IN_WORD) { 415 cmn_err(CE_WARN, "swrand: The value of 160-bit block " 416 "random bytes are same as the previous one.\n"); 417 /* discard random bytes and return error */ 418 return (EIO); 419 } 420 421 bcopy(tempout, previous_bytes, HASHSIZE); 422 423 bcopy(tempout, ptr, size); 424 if (len < HASHSIZE) { 425 leftover_bytes = HASHSIZE - bytes; 426 bcopy((uint8_t *)tempout + bytes, leftover, 427 leftover_bytes); 428 } 429 430 ptr += size; 431 len -= size; 432 BUMP_SWRAND_STATS(ss_bytesOut, size); 433 } 434 435 /* Zero out sensitive information */ 436 bzero(digest, HASHSIZE); 437 bzero(tempout, HASHSIZE); 438 mutex_exit(&srndpool_lock); 439 return (0); 440 } 441 442 #define SWRAND_ADD_BYTES(ptr, len, i, pool) \ 443 ASSERT((ptr) != NULL && (len) > 0); \ 444 BUMP_SWRAND_STATS(ss_bytesIn, (len)); \ 445 while ((len)--) { \ 446 (pool)[(i)++] ^= *(ptr); \ 447 (ptr)++; \ 448 (i) &= (RNDPOOLSIZE - 1); \ 449 } 450 451 /* Write some more user-provided entropy to the pool */ 452 static void 453 swrand_add_bytes(uint8_t *ptr, size_t len) 454 { 455 uint8_t *pool = (uint8_t *)srndpool; 456 457 ASSERT(MUTEX_HELD(&srndpool_lock)); 458 SWRAND_ADD_BYTES(ptr, len, pindex, pool); 459 } 460 461 /* 462 * Add bytes to buffer. Adding the buffer to the random pool 463 * is deferred until the random pool is mixed. 464 */ 465 static void 466 swrand_add_bytes_later(uint8_t *ptr, size_t len) 467 { 468 uint8_t *pool = (uint8_t *)buffer; 469 470 ASSERT(MUTEX_HELD(&buffer_lock)); 471 SWRAND_ADD_BYTES(ptr, len, bindex, pool); 472 buffer_bytes += len; 473 } 474 475 #undef SWRAND_ADD_BYTES 476 477 /* Mix the pool */ 478 static void 479 swrand_mix_pool(uint16_t entropy_est) 480 { 481 int i, j, k, start; 482 HASH_CTX hashctx; 483 uint8_t digest[HASHSIZE]; 484 uint8_t *pool = (uint8_t *)srndpool; 485 uint8_t *bp = (uint8_t *)buffer; 486 487 ASSERT(MUTEX_HELD(&srndpool_lock)); 488 489 /* add deferred bytes */ 490 mutex_enter(&buffer_lock); 491 if (buffer_bytes > 0) { 492 if (buffer_bytes >= RNDPOOLSIZE) { 493 for (i = 0; i < RNDPOOLSIZE/4; i++) { 494 srndpool[i] ^= buffer[i]; 495 buffer[i] = 0; 496 } 497 bstart = bindex = 0; 498 } else { 499 for (i = 0; i < buffer_bytes; i++) { 500 pool[pindex++] ^= bp[bstart]; 501 bp[bstart++] = 0; 502 pindex &= (RNDPOOLSIZE - 1); 503 bstart &= (RNDPOOLSIZE - 1); 504 } 505 ASSERT(bstart == bindex); 506 } 507 buffer_bytes = 0; 508 } 509 mutex_exit(&buffer_lock); 510 511 start = 0; 512 for (i = 0; i < RNDPOOLSIZE/HASHSIZE + 1; i++) { 513 HashInit(&hashctx); 514 515 /* Hash a buffer centered on a block in the pool */ 516 if (start + HASHBUFSIZE <= RNDPOOLSIZE) 517 HashUpdate(&hashctx, &pool[start], HASHBUFSIZE); 518 else { 519 HashUpdate(&hashctx, &pool[start], 520 RNDPOOLSIZE - start); 521 HashUpdate(&hashctx, pool, 522 HASHBUFSIZE - RNDPOOLSIZE + start); 523 } 524 HashFinal(digest, &hashctx); 525 526 /* XOR the hash result back into the block */ 527 k = (start + HASHSIZE) & (RNDPOOLSIZE - 1); 528 for (j = 0; j < HASHSIZE; j++) { 529 pool[k++] ^= digest[j]; 530 k &= (RNDPOOLSIZE - 1); 531 } 532 533 /* Slide the hash buffer and repeat with next block */ 534 start = (start + HASHSIZE) & (RNDPOOLSIZE - 1); 535 } 536 537 entropy_bits += entropy_est; 538 if (entropy_bits > CRYPTO_BYTES2BITS(RNDPOOLSIZE)) 539 entropy_bits = CRYPTO_BYTES2BITS(RNDPOOLSIZE); 540 541 swrand_stats.ss_entEst = entropy_bits; 542 BUMP_SWRAND_STATS(ss_entIn, entropy_est); 543 } 544 545 static void 546 swrand_add_entropy_later(uint8_t *ptr, size_t len) 547 { 548 mutex_enter(&buffer_lock); 549 swrand_add_bytes_later(ptr, len); 550 mutex_exit(&buffer_lock); 551 } 552 553 static void 554 swrand_add_entropy(uint8_t *ptr, size_t len, uint16_t entropy_est) 555 { 556 mutex_enter(&srndpool_lock); 557 swrand_add_bytes(ptr, len); 558 swrand_mix_pool(entropy_est); 559 mutex_exit(&srndpool_lock); 560 } 561 562 /* 563 * The physmem_* routines below generate entropy by reading blocks of 564 * physical memory. Entropy is gathered in a couple of ways: 565 * 566 * - By reading blocks of physical memory and detecting if changes 567 * occurred in the blocks read. 568 * 569 * - By measuring the time it takes to load and hash a block of memory 570 * and computing the differences in the measured time. 571 * 572 * The first method was used in the CryptoRand implementation. Physical 573 * memory is divided into blocks of fixed size. A block of memory is 574 * chosen from the possible blocks and hashed to produce a digest. This 575 * digest is then mixed into the pool. A single bit from the digest is 576 * used as a parity bit or "checksum" and compared against the previous 577 * "checksum" computed for the block. If the single-bit checksum has not 578 * changed, no entropy is credited to the pool. If there is a change, 579 * then the assumption is that at least one bit in the block has changed. 580 * The possible locations within the memory block of where the bit change 581 * occurred is used as a measure of entropy. For example, if a block 582 * size of 4096 bytes is used, about log_2(4096*8)=15 bits worth of 583 * entropy is available. Because the single-bit checksum will miss half 584 * of the changes, the amount of entropy credited to the pool is doubled 585 * when a change is detected. With a 4096 byte block size, a block 586 * change will add a total of 30 bits of entropy to the pool. 587 * 588 * The second method measures the amount of time it takes to read and 589 * hash a physical memory block (as described above). The time measured 590 * can vary depending on system load, scheduling and other factors. 591 * Differences between consecutive measurements are computed to come up 592 * with an entropy estimate. The first, second, and third order delta is 593 * calculated to determine the minimum delta value. The number of bits 594 * present in this minimum delta value is the entropy estimate. This 595 * entropy estimation technique using time deltas is similar to that used 596 * in /dev/random implementations from Linux/BSD. 597 */ 598 599 static int 600 physmem_ent_init(physmem_entsrc_t *entsrc) 601 { 602 uint8_t *ptr; 603 int i; 604 605 bzero(entsrc, sizeof (*entsrc)); 606 607 /* 608 * The maximum entropy amount in bits per block of memory read is 609 * log_2(MEMBLOCKSIZE * 8); 610 */ 611 i = CRYPTO_BYTES2BITS(MEMBLOCKSIZE); 612 while (i >>= 1) 613 entsrc->entperblock++; 614 615 /* Initialize entsrc->nblocks */ 616 physmem_count_blocks(); 617 618 if (entsrc->nblocks == 0) { 619 cmn_err(CE_WARN, "no memory blocks to scan!"); 620 return (-1); 621 } 622 623 /* Allocate space for the parity vector and memory page */ 624 entsrc->parity = kmem_alloc(howmany(entsrc->nblocks, 8), 625 KM_SLEEP); 626 entsrc->pmbuf = vmem_alloc(heap_arena, PAGESIZE, VM_SLEEP); 627 628 629 /* Initialize parity vector with bits from the pool */ 630 i = howmany(entsrc->nblocks, 8); 631 ptr = entsrc->parity; 632 while (i > 0) { 633 if (i > RNDPOOLSIZE) { 634 bcopy(srndpool, ptr, RNDPOOLSIZE); 635 mutex_enter(&srndpool_lock); 636 swrand_mix_pool(0); 637 mutex_exit(&srndpool_lock); 638 ptr += RNDPOOLSIZE; 639 i -= RNDPOOLSIZE; 640 } else { 641 bcopy(srndpool, ptr, i); 642 break; 643 } 644 } 645 646 /* Generate some entropy to further initialize the pool */ 647 mutex_enter(&srndpool_lock); 648 physmem_ent_gen(entsrc); 649 entropy_bits = 0; 650 mutex_exit(&srndpool_lock); 651 652 return (0); 653 } 654 655 static void 656 physmem_ent_fini(physmem_entsrc_t *entsrc) 657 { 658 if (entsrc->pmbuf != NULL) 659 vmem_free(heap_arena, entsrc->pmbuf, PAGESIZE); 660 if (entsrc->parity != NULL) 661 kmem_free(entsrc->parity, howmany(entsrc->nblocks, 8)); 662 bzero(entsrc, sizeof (*entsrc)); 663 } 664 665 static void 666 physmem_ent_gen(physmem_entsrc_t *entsrc) 667 { 668 struct memlist *pmem; 669 offset_t offset, poffset; 670 pfn_t pfn; 671 int i, nbytes, len, ent = 0; 672 uint32_t block, oblock; 673 hrtime_t ts1, ts2, diff, delta, delta2, delta3; 674 uint8_t digest[HASHSIZE]; 675 HASH_CTX ctx; 676 page_t *pp; 677 678 /* 679 * Use each 32-bit quantity in the pool to pick a memory 680 * block to read. 681 */ 682 for (i = 0; i < RNDPOOLSIZE/4; i++) { 683 684 /* If the pool is "full", stop after one block */ 685 if (entropy_bits + ent >= CRYPTO_BYTES2BITS(RNDPOOLSIZE)) { 686 if (i > 0) 687 break; 688 } 689 690 /* 691 * This lock protects reading of phys_install. 692 * Any changes to this list, by DR, are done while 693 * holding this lock. So, holding this lock is sufficient 694 * to handle DR also. 695 */ 696 memlist_read_lock(); 697 698 /* We're left with less than 4K of memory after DR */ 699 ASSERT(entsrc->nblocks > 0); 700 701 /* Pick a memory block to read */ 702 block = oblock = srndpool[i] % entsrc->nblocks; 703 704 for (pmem = phys_install; pmem != NULL; pmem = pmem->ml_next) { 705 if (block < pmem->ml_size / MEMBLOCKSIZE) 706 break; 707 block -= pmem->ml_size / MEMBLOCKSIZE; 708 } 709 710 ASSERT(pmem != NULL); 711 712 offset = pmem->ml_address + block * MEMBLOCKSIZE; 713 714 if (!address_in_memlist(phys_install, offset, MEMBLOCKSIZE)) { 715 memlist_read_unlock(); 716 continue; 717 } 718 719 /* 720 * Do an initial check to see if the address is safe 721 */ 722 if (plat_hold_page(offset >> PAGESHIFT, PLAT_HOLD_NO_LOCK, NULL) 723 == PLAT_HOLD_FAIL) { 724 memlist_read_unlock(); 725 continue; 726 } 727 728 /* 729 * Figure out which page to load to read the 730 * memory block. Load the page and compute the 731 * hash of the memory block. 732 */ 733 len = MEMBLOCKSIZE; 734 ts1 = gethrtime(); 735 HashInit(&ctx); 736 while (len) { 737 pfn = offset >> PAGESHIFT; 738 poffset = offset & PAGEOFFSET; 739 nbytes = PAGESIZE - poffset < len ? 740 PAGESIZE - poffset : len; 741 742 /* 743 * Re-check the offset, and lock the frame. If the 744 * page was given away after the above check, we'll 745 * just bail out. 746 */ 747 if (plat_hold_page(pfn, PLAT_HOLD_LOCK, &pp) == 748 PLAT_HOLD_FAIL) 749 break; 750 751 hat_devload(kas.a_hat, entsrc->pmbuf, 752 PAGESIZE, pfn, PROT_READ, 753 HAT_LOAD_NOCONSIST | HAT_LOAD_LOCK); 754 755 HashUpdate(&ctx, (uint8_t *)entsrc->pmbuf + poffset, 756 nbytes); 757 758 hat_unload(kas.a_hat, entsrc->pmbuf, PAGESIZE, 759 HAT_UNLOAD_UNLOCK); 760 761 plat_release_page(pp); 762 763 len -= nbytes; 764 offset += nbytes; 765 } 766 /* We got our pages. Let the DR roll */ 767 memlist_read_unlock(); 768 769 /* See if we had to bail out due to a page being given away */ 770 if (len) 771 continue; 772 773 HashFinal(digest, &ctx); 774 ts2 = gethrtime(); 775 776 /* 777 * Compute the time it took to load and hash the 778 * block and compare it against the previous 779 * measurement. The delta of the time values 780 * provides a small amount of entropy. The 781 * minimum of the first, second, and third order 782 * delta is used to estimate how much entropy 783 * is present. 784 */ 785 diff = ts2 - ts1; 786 delta = diff - entsrc->last_diff; 787 if (delta < 0) 788 delta = -delta; 789 delta2 = delta - entsrc->last_delta; 790 if (delta2 < 0) 791 delta2 = -delta2; 792 delta3 = delta2 - entsrc->last_delta2; 793 if (delta3 < 0) 794 delta3 = -delta3; 795 entsrc->last_diff = diff; 796 entsrc->last_delta = delta; 797 entsrc->last_delta2 = delta2; 798 799 if (delta > delta2) 800 delta = delta2; 801 if (delta > delta3) 802 delta = delta3; 803 delta2 = 0; 804 while (delta >>= 1) 805 delta2++; 806 ent += delta2; 807 808 /* 809 * If the memory block has changed, credit the pool with 810 * the entropy estimate. The entropy estimate is doubled 811 * because the single-bit checksum misses half the change 812 * on average. 813 */ 814 if (physmem_parity_update(entsrc->parity, oblock, 815 digest[0] & 1)) 816 ent += 2 * entsrc->entperblock; 817 818 /* Add the entropy bytes to the pool */ 819 swrand_add_bytes(digest, HASHSIZE); 820 swrand_add_bytes((uint8_t *)&ts1, sizeof (ts1)); 821 swrand_add_bytes((uint8_t *)&ts2, sizeof (ts2)); 822 } 823 824 swrand_mix_pool(ent); 825 } 826 827 static int 828 physmem_parity_update(uint8_t *parity_vec, uint32_t block, int parity) 829 { 830 /* Test and set the parity bit, return 1 if changed */ 831 if (parity == ((parity_vec[block >> 3] >> (block & 7)) & 1)) 832 return (0); 833 parity_vec[block >> 3] ^= 1 << (block & 7); 834 return (1); 835 } 836 837 /* Compute number of memory blocks available to scan */ 838 static void 839 physmem_count_blocks() 840 { 841 struct memlist *pmem; 842 843 memlist_read_lock(); 844 entsrc.nblocks = 0; 845 for (pmem = phys_install; pmem != NULL; pmem = pmem->ml_next) { 846 entsrc.nblocks += pmem->ml_size / MEMBLOCKSIZE; 847 if (entsrc.nblocks > MAXMEMBLOCKS) { 848 entsrc.nblocks = MAXMEMBLOCKS; 849 break; 850 } 851 } 852 memlist_read_unlock(); 853 } 854 855 /* 856 * Dynamic Reconfiguration call-back functions 857 */ 858 859 /* ARGSUSED */ 860 static void 861 rnd_dr_callback_post_add(void *arg, pgcnt_t delta) 862 { 863 /* More memory is available now, so update entsrc->nblocks. */ 864 physmem_count_blocks(); 865 } 866 867 /* Call-back routine invoked before the DR starts a memory removal. */ 868 /* ARGSUSED */ 869 static int 870 rnd_dr_callback_pre_del(void *arg, pgcnt_t delta) 871 { 872 return (0); 873 } 874 875 /* Call-back routine invoked after the DR starts a memory removal. */ 876 /* ARGSUSED */ 877 static void 878 rnd_dr_callback_post_del(void *arg, pgcnt_t delta, int cancelled) 879 { 880 /* Memory has shrunk, so update entsrc->nblocks. */ 881 physmem_count_blocks(); 882 } 883 884 /* Timeout handling to gather entropy from physmem events */ 885 static void 886 swrand_schedule_timeout(void) 887 { 888 clock_t ut; /* time in microseconds */ 889 890 ASSERT(MUTEX_HELD(&srndpool_lock)); 891 /* 892 * The new timeout value is taken from the pool of random bits. 893 * We're merely reading the first 32 bits from the pool here, not 894 * consuming any entropy. 895 * This routine is usually called right after stirring the pool, so 896 * srndpool[0] will have a *fresh* random value each time. 897 * The timeout multiplier value is a random value between 0.7 sec and 898 * 1.748575 sec (0.7 sec + 0xFFFFF microseconds). 899 * The new timeout is TIMEOUT_INTERVAL times that multiplier. 900 */ 901 ut = 700000 + (clock_t)(srndpool[0] & 0xFFFFF); 902 rnd_timeout_id = timeout(rnd_handler, NULL, 903 TIMEOUT_INTERVAL * drv_usectohz(ut)); 904 } 905 906 /*ARGSUSED*/ 907 static void 908 rnd_handler(void *arg) 909 { 910 mutex_enter(&srndpool_lock); 911 912 physmem_ent_gen(&entsrc); 913 if (snum_waiters > 0) 914 cv_broadcast(&srndpool_read_cv); 915 swrand_schedule_timeout(); 916 917 mutex_exit(&srndpool_lock); 918 } 919 920 /* 921 * Swrand Power-Up Self-Test 922 */ 923 void 924 swrand_POST(int *rc) 925 { 926 927 *rc = fips_rng_post(); 928 929 } 930