zio_checksum.c revision 321610
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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. 23 * Copyright (c) 2013, 2016 by Delphix. All rights reserved. 24 * Copyright (c) 2013, Joyent, Inc. All rights reserved. 25 * Copyright 2013 Saso Kiselkov. All rights reserved. 26 */ 27 28#include <sys/zfs_context.h> 29#include <sys/spa.h> 30#include <sys/spa_impl.h> 31#include <sys/zio.h> 32#include <sys/zio_checksum.h> 33#include <sys/zil.h> 34#include <sys/abd.h> 35#include <zfs_fletcher.h> 36 37/* 38 * Checksum vectors. 39 * 40 * In the SPA, everything is checksummed. We support checksum vectors 41 * for three distinct reasons: 42 * 43 * 1. Different kinds of data need different levels of protection. 44 * For SPA metadata, we always want a very strong checksum. 45 * For user data, we let users make the trade-off between speed 46 * and checksum strength. 47 * 48 * 2. Cryptographic hash and MAC algorithms are an area of active research. 49 * It is likely that in future hash functions will be at least as strong 50 * as current best-of-breed, and may be substantially faster as well. 51 * We want the ability to take advantage of these new hashes as soon as 52 * they become available. 53 * 54 * 3. If someone develops hardware that can compute a strong hash quickly, 55 * we want the ability to take advantage of that hardware. 56 * 57 * Of course, we don't want a checksum upgrade to invalidate existing 58 * data, so we store the checksum *function* in eight bits of the bp. 59 * This gives us room for up to 256 different checksum functions. 60 * 61 * When writing a block, we always checksum it with the latest-and-greatest 62 * checksum function of the appropriate strength. When reading a block, 63 * we compare the expected checksum against the actual checksum, which we 64 * compute via the checksum function specified by BP_GET_CHECKSUM(bp). 65 * 66 * SALTED CHECKSUMS 67 * 68 * To enable the use of less secure hash algorithms with dedup, we 69 * introduce the notion of salted checksums (MACs, really). A salted 70 * checksum is fed both a random 256-bit value (the salt) and the data 71 * to be checksummed. This salt is kept secret (stored on the pool, but 72 * never shown to the user). Thus even if an attacker knew of collision 73 * weaknesses in the hash algorithm, they won't be able to mount a known 74 * plaintext attack on the DDT, since the actual hash value cannot be 75 * known ahead of time. How the salt is used is algorithm-specific 76 * (some might simply prefix it to the data block, others might need to 77 * utilize a full-blown HMAC). On disk the salt is stored in a ZAP 78 * object in the MOS (DMU_POOL_CHECKSUM_SALT). 79 * 80 * CONTEXT TEMPLATES 81 * 82 * Some hashing algorithms need to perform a substantial amount of 83 * initialization work (e.g. salted checksums above may need to pre-hash 84 * the salt) before being able to process data. Performing this 85 * redundant work for each block would be wasteful, so we instead allow 86 * a checksum algorithm to do the work once (the first time it's used) 87 * and then keep this pre-initialized context as a template inside the 88 * spa_t (spa_cksum_tmpls). If the zio_checksum_info_t contains 89 * non-NULL ci_tmpl_init and ci_tmpl_free callbacks, they are used to 90 * construct and destruct the pre-initialized checksum context. The 91 * pre-initialized context is then reused during each checksum 92 * invocation and passed to the checksum function. 93 */ 94 95/*ARGSUSED*/ 96static void 97abd_checksum_off(abd_t *abd, uint64_t size, 98 const void *ctx_template, zio_cksum_t *zcp) 99{ 100 ZIO_SET_CHECKSUM(zcp, 0, 0, 0, 0); 101} 102 103/*ARGSUSED*/ 104void 105abd_fletcher_2_native(abd_t *abd, uint64_t size, 106 const void *ctx_template, zio_cksum_t *zcp) 107{ 108 fletcher_init(zcp); 109 (void) abd_iterate_func(abd, 0, size, 110 fletcher_2_incremental_native, zcp); 111} 112 113/*ARGSUSED*/ 114void 115abd_fletcher_2_byteswap(abd_t *abd, uint64_t size, 116 const void *ctx_template, zio_cksum_t *zcp) 117{ 118 fletcher_init(zcp); 119 (void) abd_iterate_func(abd, 0, size, 120 fletcher_2_incremental_byteswap, zcp); 121} 122 123/*ARGSUSED*/ 124void 125abd_fletcher_4_native(abd_t *abd, uint64_t size, 126 const void *ctx_template, zio_cksum_t *zcp) 127{ 128 fletcher_init(zcp); 129 (void) abd_iterate_func(abd, 0, size, 130 fletcher_4_incremental_native, zcp); 131} 132 133/*ARGSUSED*/ 134void 135abd_fletcher_4_byteswap(abd_t *abd, uint64_t size, 136 const void *ctx_template, zio_cksum_t *zcp) 137{ 138 fletcher_init(zcp); 139 (void) abd_iterate_func(abd, 0, size, 140 fletcher_4_incremental_byteswap, zcp); 141} 142 143zio_checksum_info_t zio_checksum_table[ZIO_CHECKSUM_FUNCTIONS] = { 144 {{NULL, NULL}, NULL, NULL, 0, "inherit"}, 145 {{NULL, NULL}, NULL, NULL, 0, "on"}, 146 {{abd_checksum_off, abd_checksum_off}, 147 NULL, NULL, 0, "off"}, 148 {{abd_checksum_SHA256, abd_checksum_SHA256}, 149 NULL, NULL, ZCHECKSUM_FLAG_METADATA | ZCHECKSUM_FLAG_EMBEDDED, 150 "label"}, 151 {{abd_checksum_SHA256, abd_checksum_SHA256}, 152 NULL, NULL, ZCHECKSUM_FLAG_METADATA | ZCHECKSUM_FLAG_EMBEDDED, 153 "gang_header"}, 154 {{abd_fletcher_2_native, abd_fletcher_2_byteswap}, 155 NULL, NULL, ZCHECKSUM_FLAG_EMBEDDED, "zilog"}, 156 {{abd_fletcher_2_native, abd_fletcher_2_byteswap}, 157 NULL, NULL, 0, "fletcher2"}, 158 {{abd_fletcher_4_native, abd_fletcher_4_byteswap}, 159 NULL, NULL, ZCHECKSUM_FLAG_METADATA, "fletcher4"}, 160 {{abd_checksum_SHA256, abd_checksum_SHA256}, 161 NULL, NULL, ZCHECKSUM_FLAG_METADATA | ZCHECKSUM_FLAG_DEDUP | 162 ZCHECKSUM_FLAG_NOPWRITE, "sha256"}, 163 {{abd_fletcher_4_native, abd_fletcher_4_byteswap}, 164 NULL, NULL, ZCHECKSUM_FLAG_EMBEDDED, "zilog2"}, 165 {{abd_checksum_off, abd_checksum_off}, 166 NULL, NULL, 0, "noparity"}, 167 {{abd_checksum_SHA512_native, abd_checksum_SHA512_byteswap}, 168 NULL, NULL, ZCHECKSUM_FLAG_METADATA | ZCHECKSUM_FLAG_DEDUP | 169 ZCHECKSUM_FLAG_NOPWRITE, "sha512"}, 170 {{abd_checksum_skein_native, abd_checksum_skein_byteswap}, 171 abd_checksum_skein_tmpl_init, abd_checksum_skein_tmpl_free, 172 ZCHECKSUM_FLAG_METADATA | ZCHECKSUM_FLAG_DEDUP | 173 ZCHECKSUM_FLAG_SALTED | ZCHECKSUM_FLAG_NOPWRITE, "skein"}, 174#ifdef illumos 175 {{abd_checksum_edonr_native, abd_checksum_edonr_byteswap}, 176 abd_checksum_edonr_tmpl_init, abd_checksum_edonr_tmpl_free, 177 ZCHECKSUM_FLAG_METADATA | ZCHECKSUM_FLAG_SALTED | 178 ZCHECKSUM_FLAG_NOPWRITE, "edonr"}, 179#endif 180}; 181 182/* 183 * The flag corresponding to the "verify" in dedup=[checksum,]verify 184 * must be cleared first, so callers should use ZIO_CHECKSUM_MASK. 185 */ 186spa_feature_t 187zio_checksum_to_feature(enum zio_checksum cksum) 188{ 189 VERIFY((cksum & ~ZIO_CHECKSUM_MASK) == 0); 190 191 switch (cksum) { 192 case ZIO_CHECKSUM_SHA512: 193 return (SPA_FEATURE_SHA512); 194 case ZIO_CHECKSUM_SKEIN: 195 return (SPA_FEATURE_SKEIN); 196#ifdef illumos 197 case ZIO_CHECKSUM_EDONR: 198 return (SPA_FEATURE_EDONR); 199#endif 200 } 201 return (SPA_FEATURE_NONE); 202} 203 204enum zio_checksum 205zio_checksum_select(enum zio_checksum child, enum zio_checksum parent) 206{ 207 ASSERT(child < ZIO_CHECKSUM_FUNCTIONS); 208 ASSERT(parent < ZIO_CHECKSUM_FUNCTIONS); 209 ASSERT(parent != ZIO_CHECKSUM_INHERIT && parent != ZIO_CHECKSUM_ON); 210 211 if (child == ZIO_CHECKSUM_INHERIT) 212 return (parent); 213 214 if (child == ZIO_CHECKSUM_ON) 215 return (ZIO_CHECKSUM_ON_VALUE); 216 217 return (child); 218} 219 220enum zio_checksum 221zio_checksum_dedup_select(spa_t *spa, enum zio_checksum child, 222 enum zio_checksum parent) 223{ 224 ASSERT((child & ZIO_CHECKSUM_MASK) < ZIO_CHECKSUM_FUNCTIONS); 225 ASSERT((parent & ZIO_CHECKSUM_MASK) < ZIO_CHECKSUM_FUNCTIONS); 226 ASSERT(parent != ZIO_CHECKSUM_INHERIT && parent != ZIO_CHECKSUM_ON); 227 228 if (child == ZIO_CHECKSUM_INHERIT) 229 return (parent); 230 231 if (child == ZIO_CHECKSUM_ON) 232 return (spa_dedup_checksum(spa)); 233 234 if (child == (ZIO_CHECKSUM_ON | ZIO_CHECKSUM_VERIFY)) 235 return (spa_dedup_checksum(spa) | ZIO_CHECKSUM_VERIFY); 236 237 ASSERT((zio_checksum_table[child & ZIO_CHECKSUM_MASK].ci_flags & 238 ZCHECKSUM_FLAG_DEDUP) || 239 (child & ZIO_CHECKSUM_VERIFY) || child == ZIO_CHECKSUM_OFF); 240 241 return (child); 242} 243 244/* 245 * Set the external verifier for a gang block based on <vdev, offset, txg>, 246 * a tuple which is guaranteed to be unique for the life of the pool. 247 */ 248static void 249zio_checksum_gang_verifier(zio_cksum_t *zcp, blkptr_t *bp) 250{ 251 dva_t *dva = BP_IDENTITY(bp); 252 uint64_t txg = BP_PHYSICAL_BIRTH(bp); 253 254 ASSERT(BP_IS_GANG(bp)); 255 256 ZIO_SET_CHECKSUM(zcp, DVA_GET_VDEV(dva), DVA_GET_OFFSET(dva), txg, 0); 257} 258 259/* 260 * Set the external verifier for a label block based on its offset. 261 * The vdev is implicit, and the txg is unknowable at pool open time -- 262 * hence the logic in vdev_uberblock_load() to find the most recent copy. 263 */ 264static void 265zio_checksum_label_verifier(zio_cksum_t *zcp, uint64_t offset) 266{ 267 ZIO_SET_CHECKSUM(zcp, offset, 0, 0, 0); 268} 269 270/* 271 * Calls the template init function of a checksum which supports context 272 * templates and installs the template into the spa_t. 273 */ 274static void 275zio_checksum_template_init(enum zio_checksum checksum, spa_t *spa) 276{ 277 zio_checksum_info_t *ci = &zio_checksum_table[checksum]; 278 279 if (ci->ci_tmpl_init == NULL) 280 return; 281 if (spa->spa_cksum_tmpls[checksum] != NULL) 282 return; 283 284 VERIFY(ci->ci_tmpl_free != NULL); 285 mutex_enter(&spa->spa_cksum_tmpls_lock); 286 if (spa->spa_cksum_tmpls[checksum] == NULL) { 287 spa->spa_cksum_tmpls[checksum] = 288 ci->ci_tmpl_init(&spa->spa_cksum_salt); 289 VERIFY(spa->spa_cksum_tmpls[checksum] != NULL); 290 } 291 mutex_exit(&spa->spa_cksum_tmpls_lock); 292} 293 294/* 295 * Generate the checksum. 296 */ 297void 298zio_checksum_compute(zio_t *zio, enum zio_checksum checksum, 299 abd_t *abd, uint64_t size) 300{ 301 blkptr_t *bp = zio->io_bp; 302 uint64_t offset = zio->io_offset; 303 zio_checksum_info_t *ci = &zio_checksum_table[checksum]; 304 zio_cksum_t cksum; 305 spa_t *spa = zio->io_spa; 306 307 ASSERT((uint_t)checksum < ZIO_CHECKSUM_FUNCTIONS); 308 ASSERT(ci->ci_func[0] != NULL); 309 310 zio_checksum_template_init(checksum, spa); 311 312 if (ci->ci_flags & ZCHECKSUM_FLAG_EMBEDDED) { 313 zio_eck_t *eck; 314 void *data = abd_to_buf(abd); 315 316 if (checksum == ZIO_CHECKSUM_ZILOG2) { 317 zil_chain_t *zilc = data; 318 319 size = P2ROUNDUP_TYPED(zilc->zc_nused, ZIL_MIN_BLKSZ, 320 uint64_t); 321 eck = &zilc->zc_eck; 322 } else { 323 eck = (zio_eck_t *)((char *)data + size) - 1; 324 } 325 if (checksum == ZIO_CHECKSUM_GANG_HEADER) 326 zio_checksum_gang_verifier(&eck->zec_cksum, bp); 327 else if (checksum == ZIO_CHECKSUM_LABEL) 328 zio_checksum_label_verifier(&eck->zec_cksum, offset); 329 else 330 bp->blk_cksum = eck->zec_cksum; 331 eck->zec_magic = ZEC_MAGIC; 332 ci->ci_func[0](abd, size, spa->spa_cksum_tmpls[checksum], 333 &cksum); 334 eck->zec_cksum = cksum; 335 } else { 336 ci->ci_func[0](abd, size, spa->spa_cksum_tmpls[checksum], 337 &bp->blk_cksum); 338 } 339} 340 341int 342zio_checksum_error_impl(spa_t *spa, blkptr_t *bp, enum zio_checksum checksum, 343 abd_t *abd, uint64_t size, uint64_t offset, zio_bad_cksum_t *info) 344{ 345 zio_checksum_info_t *ci = &zio_checksum_table[checksum]; 346 zio_cksum_t actual_cksum, expected_cksum; 347 int byteswap; 348 349 if (checksum >= ZIO_CHECKSUM_FUNCTIONS || ci->ci_func[0] == NULL) 350 return (SET_ERROR(EINVAL)); 351 352 zio_checksum_template_init(checksum, spa); 353 354 if (ci->ci_flags & ZCHECKSUM_FLAG_EMBEDDED) { 355 zio_eck_t *eck; 356 zio_cksum_t verifier; 357 uint64_t data_size = size; 358 void *data = abd_borrow_buf_copy(abd, data_size); 359 360 if (checksum == ZIO_CHECKSUM_ZILOG2) { 361 zil_chain_t *zilc = data; 362 uint64_t nused; 363 364 eck = &zilc->zc_eck; 365 if (eck->zec_magic == ZEC_MAGIC) { 366 nused = zilc->zc_nused; 367 } else if (eck->zec_magic == BSWAP_64(ZEC_MAGIC)) { 368 nused = BSWAP_64(zilc->zc_nused); 369 } else { 370 abd_return_buf(abd, data, data_size); 371 return (SET_ERROR(ECKSUM)); 372 } 373 374 if (nused > data_size) { 375 abd_return_buf(abd, data, data_size); 376 return (SET_ERROR(ECKSUM)); 377 } 378 379 size = P2ROUNDUP_TYPED(nused, ZIL_MIN_BLKSZ, uint64_t); 380 } else { 381 eck = (zio_eck_t *)((char *)data + data_size) - 1; 382 } 383 384 if (checksum == ZIO_CHECKSUM_GANG_HEADER) 385 zio_checksum_gang_verifier(&verifier, bp); 386 else if (checksum == ZIO_CHECKSUM_LABEL) 387 zio_checksum_label_verifier(&verifier, offset); 388 else 389 verifier = bp->blk_cksum; 390 391 byteswap = (eck->zec_magic == BSWAP_64(ZEC_MAGIC)); 392 393 if (byteswap) 394 byteswap_uint64_array(&verifier, sizeof (zio_cksum_t)); 395 396 size_t eck_offset = (size_t)(&eck->zec_cksum) - (size_t)data; 397 expected_cksum = eck->zec_cksum; 398 eck->zec_cksum = verifier; 399 abd_return_buf_copy(abd, data, data_size); 400 401 ci->ci_func[byteswap](abd, size, 402 spa->spa_cksum_tmpls[checksum], &actual_cksum); 403 abd_copy_from_buf_off(abd, &expected_cksum, 404 eck_offset, sizeof (zio_cksum_t)); 405 406 if (byteswap) { 407 byteswap_uint64_array(&expected_cksum, 408 sizeof (zio_cksum_t)); 409 } 410 } else { 411 byteswap = BP_SHOULD_BYTESWAP(bp); 412 expected_cksum = bp->blk_cksum; 413 ci->ci_func[byteswap](abd, size, 414 spa->spa_cksum_tmpls[checksum], &actual_cksum); 415 } 416 417 if (info != NULL) { 418 info->zbc_expected = expected_cksum; 419 info->zbc_actual = actual_cksum; 420 info->zbc_checksum_name = ci->ci_name; 421 info->zbc_byteswapped = byteswap; 422 info->zbc_injected = 0; 423 info->zbc_has_cksum = 1; 424 } 425 426 if (!ZIO_CHECKSUM_EQUAL(actual_cksum, expected_cksum)) 427 return (SET_ERROR(ECKSUM)); 428 429 return (0); 430} 431 432int 433zio_checksum_error(zio_t *zio, zio_bad_cksum_t *info) 434{ 435 blkptr_t *bp = zio->io_bp; 436 uint_t checksum = (bp == NULL ? zio->io_prop.zp_checksum : 437 (BP_IS_GANG(bp) ? ZIO_CHECKSUM_GANG_HEADER : BP_GET_CHECKSUM(bp))); 438 int error; 439 uint64_t size = (bp == NULL ? zio->io_size : 440 (BP_IS_GANG(bp) ? SPA_GANGBLOCKSIZE : BP_GET_PSIZE(bp))); 441 uint64_t offset = zio->io_offset; 442 abd_t *data = zio->io_abd; 443 spa_t *spa = zio->io_spa; 444 445 error = zio_checksum_error_impl(spa, bp, checksum, data, size, 446 offset, info); 447 448 if (zio_injection_enabled && error == 0 && zio->io_error == 0) { 449 error = zio_handle_fault_injection(zio, ECKSUM); 450 if (error != 0) 451 info->zbc_injected = 1; 452 } 453 454 return (error); 455} 456 457/* 458 * Called by a spa_t that's about to be deallocated. This steps through 459 * all of the checksum context templates and deallocates any that were 460 * initialized using the algorithm-specific template init function. 461 */ 462void 463zio_checksum_templates_free(spa_t *spa) 464{ 465 for (enum zio_checksum checksum = 0; 466 checksum < ZIO_CHECKSUM_FUNCTIONS; checksum++) { 467 if (spa->spa_cksum_tmpls[checksum] != NULL) { 468 zio_checksum_info_t *ci = &zio_checksum_table[checksum]; 469 470 VERIFY(ci->ci_tmpl_free != NULL); 471 ci->ci_tmpl_free(spa->spa_cksum_tmpls[checksum]); 472 spa->spa_cksum_tmpls[checksum] = NULL; 473 } 474 } 475} 476