git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/checksum.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "bcachefs.h"
   3 #include "checksum.h"
   4 #include "errcode.h"
   5 #include "super.h"
   6 #include "super-io.h"
   7
   8 #include <linux/crc32c.h>
   9 #include <linux/crypto.h>
  10 #include <linux/xxhash.h>
  11 #include <linux/key.h>
  12 #include <linux/random.h>
  13 #include <linux/scatterlist.h>
  14 #include <crypto/algapi.h>
  15 #include <crypto/chacha.h>
  16 #include <crypto/hash.h>
  17 #include <crypto/poly1305.h>
  18 #include <crypto/skcipher.h>
  19 #include <keys/user-type.h>
  20
  21 /*
  22  * bch2_checksum state is an abstraction of the checksum state calculated over different pages.
  23  * it features page merging without having the checksum algorithm lose its state.
  24  * for native checksum aglorithms (like crc), a default seed value will do.
  25  * for hash-like algorithms, a state needs to be stored
  26  */
  27
  28 struct bch2_checksum_state {
  29         union {
  30                 u64 seed;
  31                 struct xxh64_state h64state;
  32         };
  33         unsigned int type;
  34 };
  35
  36 static void bch2_checksum_init(struct bch2_checksum_state *state)
  37 {
  38         switch (state->type) {
  39         case BCH_CSUM_none:
  40         case BCH_CSUM_crc32c:
  41         case BCH_CSUM_crc64:
  42                 state->seed = 0;
  43                 break;
  44         case BCH_CSUM_crc32c_nonzero:
  45                 state->seed = U32_MAX;
  46                 break;
  47         case BCH_CSUM_crc64_nonzero:
  48                 state->seed = U64_MAX;
  49                 break;
  50         case BCH_CSUM_xxhash:
  51                 xxh64_reset(&state->h64state, 0);
  52                 break;
  53         default:
  54                 BUG();
  55         }
  56 }
  57
  58 static u64 bch2_checksum_final(const struct bch2_checksum_state *state)
  59 {
  60         switch (state->type) {
  61         case BCH_CSUM_none:
  62         case BCH_CSUM_crc32c:
  63         case BCH_CSUM_crc64:
  64                 return state->seed;
  65         case BCH_CSUM_crc32c_nonzero:
  66                 return state->seed ^ U32_MAX;
  67         case BCH_CSUM_crc64_nonzero:
  68                 return state->seed ^ U64_MAX;
  69         case BCH_CSUM_xxhash:
  70                 return xxh64_digest(&state->h64state);
  71         default:
  72                 BUG();
  73         }
  74 }
  75
  76 static void bch2_checksum_update(struct bch2_checksum_state *state, const void *data, size_t len)
  77 {
  78         switch (state->type) {
  79         case BCH_CSUM_none:
  80                 return;
  81         case BCH_CSUM_crc32c_nonzero:
  82         case BCH_CSUM_crc32c:
  83                 state->seed = crc32c(state->seed, data, len);
  84                 break;
  85         case BCH_CSUM_crc64_nonzero:
  86         case BCH_CSUM_crc64:
  87                 state->seed = crc64_be(state->seed, data, len);
  88                 break;
  89         case BCH_CSUM_xxhash:
  90                 xxh64_update(&state->h64state, data, len);
  91                 break;
  92         default:
  93                 BUG();
  94         }
  95 }
  96
  97 static inline int do_encrypt_sg(struct crypto_sync_skcipher *tfm,
  98                                 struct nonce nonce,
  99                                 struct scatterlist *sg, size_t len)
 100 {
 101         SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
 102         int ret;
 103
 104         skcipher_request_set_sync_tfm(req, tfm);
 105         skcipher_request_set_crypt(req, sg, sg, len, nonce.d);
 106
 107         ret = crypto_skcipher_encrypt(req);
 108         if (ret)
 109                 pr_err("got error %i from crypto_skcipher_encrypt()", ret);
 110
 111         return ret;
 112 }
 113
 114 static inline int do_encrypt(struct crypto_sync_skcipher *tfm,
 115                               struct nonce nonce,
 116                               void *buf, size_t len)
 117 {
 118         if (!is_vmalloc_addr(buf)) {
 119                 struct scatterlist sg;
 120
 121                 sg_init_table(&sg, 1);
 122                 sg_set_page(&sg,
 123                             is_vmalloc_addr(buf)
 124                             ? vmalloc_to_page(buf)
 125                             : virt_to_page(buf),
 126                             len, offset_in_page(buf));
 127                 return do_encrypt_sg(tfm, nonce, &sg, len);
 128         } else {
 129                 unsigned pages = buf_pages(buf, len);
 130                 struct scatterlist *sg;
 131                 size_t orig_len = len;
 132                 int ret, i;
 133
 134                 sg = kmalloc_array(pages, sizeof(*sg), GFP_KERNEL);
 135                 if (!sg)
 136                         return -BCH_ERR_ENOMEM_do_encrypt;
 137
 138                 sg_init_table(sg, pages);
 139
 140                 for (i = 0; i < pages; i++) {
 141                         unsigned offset = offset_in_page(buf);
 142                         unsigned pg_len = min(len, PAGE_SIZE - offset);
 143
 144                         sg_set_page(sg + i, vmalloc_to_page(buf), pg_len, offset);
 145                         buf += pg_len;
 146                         len -= pg_len;
 147                 }
 148
 149                 ret = do_encrypt_sg(tfm, nonce, sg, orig_len);
 150                 kfree(sg);
 151                 return ret;
 152         }
 153 }
 154
 155 int bch2_chacha_encrypt_key(struct bch_key *key, struct nonce nonce,
 156                             void *buf, size_t len)
 157 {
 158         struct crypto_sync_skcipher *chacha20 =
 159                 crypto_alloc_sync_skcipher("chacha20", 0, 0);
 160         int ret;
 161
 162         if (!chacha20) {
 163                 pr_err("error requesting chacha20 module: %li", PTR_ERR(chacha20));
 164                 return PTR_ERR(chacha20);
 165         }
 166
 167         ret = crypto_skcipher_setkey(&chacha20->base,
 168                                      (void *) key, sizeof(*key));
 169         if (ret) {
 170                 pr_err("crypto_skcipher_setkey() error: %i", ret);
 171                 goto err;
 172         }
 173
 174         ret = do_encrypt(chacha20, nonce, buf, len);
 175 err:
 176         crypto_free_sync_skcipher(chacha20);
 177         return ret;
 178 }
 179
 180 static int gen_poly_key(struct bch_fs *c, struct shash_desc *desc,
 181                         struct nonce nonce)
 182 {
 183         u8 key[POLY1305_KEY_SIZE];
 184         int ret;
 185
 186         nonce.d[3] ^= BCH_NONCE_POLY;
 187
 188         memset(key, 0, sizeof(key));
 189         ret = do_encrypt(c->chacha20, nonce, key, sizeof(key));
 190         if (ret)
 191                 return ret;
 192
 193         desc->tfm = c->poly1305;
 194         crypto_shash_init(desc);
 195         crypto_shash_update(desc, key, sizeof(key));
 196         return 0;
 197 }
 198
 199 struct bch_csum bch2_checksum(struct bch_fs *c, unsigned type,
 200                               struct nonce nonce, const void *data, size_t len)
 201 {
 202         switch (type) {
 203         case BCH_CSUM_none:
 204         case BCH_CSUM_crc32c_nonzero:
 205         case BCH_CSUM_crc64_nonzero:
 206         case BCH_CSUM_crc32c:
 207         case BCH_CSUM_xxhash:
 208         case BCH_CSUM_crc64: {
 209                 struct bch2_checksum_state state;
 210
 211                 state.type = type;
 212
 213                 bch2_checksum_init(&state);
 214                 bch2_checksum_update(&state, data, len);
 215
 216                 return (struct bch_csum) { .lo = cpu_to_le64(bch2_checksum_final(&state)) };
 217         }
 218
 219         case BCH_CSUM_chacha20_poly1305_80:
 220         case BCH_CSUM_chacha20_poly1305_128: {
 221                 SHASH_DESC_ON_STACK(desc, c->poly1305);
 222                 u8 digest[POLY1305_DIGEST_SIZE];
 223                 struct bch_csum ret = { 0 };
 224
 225                 gen_poly_key(c, desc, nonce);
 226
 227                 crypto_shash_update(desc, data, len);
 228                 crypto_shash_final(desc, digest);
 229
 230                 memcpy(&ret, digest, bch_crc_bytes[type]);
 231                 return ret;
 232         }
 233         default:
 234                 BUG();
 235         }
 236 }
 237
 238 int bch2_encrypt(struct bch_fs *c, unsigned type,
 239                   struct nonce nonce, void *data, size_t len)
 240 {
 241         if (!bch2_csum_type_is_encryption(type))
 242                 return 0;
 243
 244         return do_encrypt(c->chacha20, nonce, data, len);
 245 }
 246
 247 static struct bch_csum __bch2_checksum_bio(struct bch_fs *c, unsigned type,
 248                                            struct nonce nonce, struct bio *bio,
 249                                            struct bvec_iter *iter)
 250 {
 251         struct bio_vec bv;
 252
 253         switch (type) {
 254         case BCH_CSUM_none:
 255                 return (struct bch_csum) { 0 };
 256         case BCH_CSUM_crc32c_nonzero:
 257         case BCH_CSUM_crc64_nonzero:
 258         case BCH_CSUM_crc32c:
 259         case BCH_CSUM_xxhash:
 260         case BCH_CSUM_crc64: {
 261                 struct bch2_checksum_state state;
 262
 263                 state.type = type;
 264                 bch2_checksum_init(&state);
 265
 266 #ifdef CONFIG_HIGHMEM
 267                 __bio_for_each_segment(bv, bio, *iter, *iter) {
 268                         void *p = kmap_atomic(bv.bv_page) + bv.bv_offset;
 269                         bch2_checksum_update(&state, p, bv.bv_len);
 270                         kunmap_atomic(p);
 271                 }
 272 #else
 273                 __bio_for_each_bvec(bv, bio, *iter, *iter)
 274                         bch2_checksum_update(&state, page_address(bv.bv_page) + bv.bv_offset,
 275                                 bv.bv_len);
 276 #endif
 277                 return (struct bch_csum) { .lo = cpu_to_le64(bch2_checksum_final(&state)) };
 278         }
 279
 280         case BCH_CSUM_chacha20_poly1305_80:
 281         case BCH_CSUM_chacha20_poly1305_128: {
 282                 SHASH_DESC_ON_STACK(desc, c->poly1305);
 283                 u8 digest[POLY1305_DIGEST_SIZE];
 284                 struct bch_csum ret = { 0 };
 285
 286                 gen_poly_key(c, desc, nonce);
 287
 288 #ifdef CONFIG_HIGHMEM
 289                 __bio_for_each_segment(bv, bio, *iter, *iter) {
 290                         void *p = kmap_atomic(bv.bv_page) + bv.bv_offset;
 291
 292                         crypto_shash_update(desc, p, bv.bv_len);
 293                         kunmap_atomic(p);
 294                 }
 295 #else
 296                 __bio_for_each_bvec(bv, bio, *iter, *iter)
 297                         crypto_shash_update(desc,
 298                                 page_address(bv.bv_page) + bv.bv_offset,
 299                                 bv.bv_len);
 300 #endif
 301                 crypto_shash_final(desc, digest);
 302
 303                 memcpy(&ret, digest, bch_crc_bytes[type]);
 304                 return ret;
 305         }
 306         default:
 307                 BUG();
 308         }
 309 }
 310
 311 struct bch_csum bch2_checksum_bio(struct bch_fs *c, unsigned type,
 312                                   struct nonce nonce, struct bio *bio)
 313 {
 314         struct bvec_iter iter = bio->bi_iter;
 315
 316         return __bch2_checksum_bio(c, type, nonce, bio, &iter);
 317 }
 318
 319 int __bch2_encrypt_bio(struct bch_fs *c, unsigned type,
 320                      struct nonce nonce, struct bio *bio)
 321 {
 322         struct bio_vec bv;
 323         struct bvec_iter iter;
 324         struct scatterlist sgl[16], *sg = sgl;
 325         size_t bytes = 0;
 326         int ret = 0;
 327
 328         if (!bch2_csum_type_is_encryption(type))
 329                 return 0;
 330
 331         sg_init_table(sgl, ARRAY_SIZE(sgl));
 332
 333         bio_for_each_segment(bv, bio, iter) {
 334                 if (sg == sgl + ARRAY_SIZE(sgl)) {
 335                         sg_mark_end(sg - 1);
 336
 337                         ret = do_encrypt_sg(c->chacha20, nonce, sgl, bytes);
 338                         if (ret)
 339                                 return ret;
 340
 341                         nonce = nonce_add(nonce, bytes);
 342                         bytes = 0;
 343
 344                         sg_init_table(sgl, ARRAY_SIZE(sgl));
 345                         sg = sgl;
 346                 }
 347
 348                 sg_set_page(sg++, bv.bv_page, bv.bv_len, bv.bv_offset);
 349                 bytes += bv.bv_len;
 350         }
 351
 352         sg_mark_end(sg - 1);
 353         return do_encrypt_sg(c->chacha20, nonce, sgl, bytes);
 354 }
 355
 356 struct bch_csum bch2_checksum_merge(unsigned type, struct bch_csum a,
 357                                     struct bch_csum b, size_t b_len)
 358 {
 359         struct bch2_checksum_state state;
 360
 361         state.type = type;
 362         bch2_checksum_init(&state);
 363         state.seed = (u64 __force) a.lo;
 364
 365         BUG_ON(!bch2_checksum_mergeable(type));
 366
 367         while (b_len) {
 368                 unsigned b = min_t(unsigned, b_len, PAGE_SIZE);
 369
 370                 bch2_checksum_update(&state,
 371                                 page_address(ZERO_PAGE(0)), b);
 372                 b_len -= b;
 373         }
 374         a.lo = (__le64 __force) bch2_checksum_final(&state);
 375         a.lo ^= b.lo;
 376         a.hi ^= b.hi;
 377         return a;
 378 }
 379
 380 int bch2_rechecksum_bio(struct bch_fs *c, struct bio *bio,
 381                         struct bversion version,
 382                         struct bch_extent_crc_unpacked crc_old,
 383                         struct bch_extent_crc_unpacked *crc_a,
 384                         struct bch_extent_crc_unpacked *crc_b,
 385                         unsigned len_a, unsigned len_b,
 386                         unsigned new_csum_type)
 387 {
 388         struct bvec_iter iter = bio->bi_iter;
 389         struct nonce nonce = extent_nonce(version, crc_old);
 390         struct bch_csum merged = { 0 };
 391         struct crc_split {
 392                 struct bch_extent_crc_unpacked  *crc;
 393                 unsigned                        len;
 394                 unsigned                        csum_type;
 395                 struct bch_csum                 csum;
 396         } splits[3] = {
 397                 { crc_a, len_a, new_csum_type },
 398                 { crc_b, len_b, new_csum_type },
 399                 { NULL,  bio_sectors(bio) - len_a - len_b, new_csum_type },
 400         }, *i;
 401         bool mergeable = crc_old.csum_type == new_csum_type &&
 402                 bch2_checksum_mergeable(new_csum_type);
 403         unsigned crc_nonce = crc_old.nonce;
 404
 405         BUG_ON(len_a + len_b > bio_sectors(bio));
 406         BUG_ON(crc_old.uncompressed_size != bio_sectors(bio));
 407         BUG_ON(crc_is_compressed(crc_old));
 408         BUG_ON(bch2_csum_type_is_encryption(crc_old.csum_type) !=
 409                bch2_csum_type_is_encryption(new_csum_type));
 410
 411         for (i = splits; i < splits + ARRAY_SIZE(splits); i++) {
 412                 iter.bi_size = i->len << 9;
 413                 if (mergeable || i->crc)
 414                         i->csum = __bch2_checksum_bio(c, i->csum_type,
 415                                                       nonce, bio, &iter);
 416                 else
 417                         bio_advance_iter(bio, &iter, i->len << 9);
 418                 nonce = nonce_add(nonce, i->len << 9);
 419         }
 420
 421         if (mergeable)
 422                 for (i = splits; i < splits + ARRAY_SIZE(splits); i++)
 423                         merged = bch2_checksum_merge(new_csum_type, merged,
 424                                                      i->csum, i->len << 9);
 425         else
 426                 merged = bch2_checksum_bio(c, crc_old.csum_type,
 427                                 extent_nonce(version, crc_old), bio);
 428
 429         if (bch2_crc_cmp(merged, crc_old.csum) && !c->opts.no_data_io) {
 430                 bch_err(c, "checksum error in bch2_rechecksum_bio() (memory corruption or bug?)\n"
 431                         "expected %0llx:%0llx got %0llx:%0llx (old type %s new type %s)",
 432                         crc_old.csum.hi,
 433                         crc_old.csum.lo,
 434                         merged.hi,
 435                         merged.lo,
 436                         bch2_csum_types[crc_old.csum_type],
 437                         bch2_csum_types[new_csum_type]);
 438                 return -EIO;
 439         }
 440
 441         for (i = splits; i < splits + ARRAY_SIZE(splits); i++) {
 442                 if (i->crc)
 443                         *i->crc = (struct bch_extent_crc_unpacked) {
 444                                 .csum_type              = i->csum_type,
 445                                 .compression_type       = crc_old.compression_type,
 446                                 .compressed_size        = i->len,
 447                                 .uncompressed_size      = i->len,
 448                                 .offset                 = 0,
 449                                 .live_size              = i->len,
 450                                 .nonce                  = crc_nonce,
 451                                 .csum                   = i->csum,
 452                         };
 453
 454                 if (bch2_csum_type_is_encryption(new_csum_type))
 455                         crc_nonce += i->len;
 456         }
 457
 458         return 0;
 459 }
 460
 461 /* BCH_SB_FIELD_crypt: */
 462
 463 static int bch2_sb_crypt_validate(struct bch_sb *sb,
 464                                   struct bch_sb_field *f,
 465                                   struct printbuf *err)
 466 {
 467         struct bch_sb_field_crypt *crypt = field_to_type(f, crypt);
 468
 469         if (vstruct_bytes(&crypt->field) < sizeof(*crypt)) {
 470                 prt_printf(err, "wrong size (got %zu should be %zu)",
 471                        vstruct_bytes(&crypt->field), sizeof(*crypt));
 472                 return -BCH_ERR_invalid_sb_crypt;
 473         }
 474
 475         if (BCH_CRYPT_KDF_TYPE(crypt)) {
 476                 prt_printf(err, "bad kdf type %llu", BCH_CRYPT_KDF_TYPE(crypt));
 477                 return -BCH_ERR_invalid_sb_crypt;
 478         }
 479
 480         return 0;
 481 }
 482
 483 static void bch2_sb_crypt_to_text(struct printbuf *out, struct bch_sb *sb,
 484                                   struct bch_sb_field *f)
 485 {
 486         struct bch_sb_field_crypt *crypt = field_to_type(f, crypt);
 487
 488         prt_printf(out, "KFD:               %llu", BCH_CRYPT_KDF_TYPE(crypt));
 489         prt_newline(out);
 490         prt_printf(out, "scrypt n:          %llu", BCH_KDF_SCRYPT_N(crypt));
 491         prt_newline(out);
 492         prt_printf(out, "scrypt r:          %llu", BCH_KDF_SCRYPT_R(crypt));
 493         prt_newline(out);
 494         prt_printf(out, "scrypt p:          %llu", BCH_KDF_SCRYPT_P(crypt));
 495         prt_newline(out);
 496 }
 497
 498 const struct bch_sb_field_ops bch_sb_field_ops_crypt = {
 499         .validate       = bch2_sb_crypt_validate,
 500         .to_text        = bch2_sb_crypt_to_text,
 501 };
 502
 503 #ifdef __KERNEL__
 504 static int __bch2_request_key(char *key_description, struct bch_key *key)
 505 {
 506         struct key *keyring_key;
 507         const struct user_key_payload *ukp;
 508         int ret;
 509
 510         keyring_key = request_key(&key_type_user, key_description, NULL);
 511         if (IS_ERR(keyring_key))
 512                 return PTR_ERR(keyring_key);
 513
 514         down_read(&keyring_key->sem);
 515         ukp = dereference_key_locked(keyring_key);
 516         if (ukp->datalen == sizeof(*key)) {
 517                 memcpy(key, ukp->data, ukp->datalen);
 518                 ret = 0;
 519         } else {
 520                 ret = -EINVAL;
 521         }
 522         up_read(&keyring_key->sem);
 523         key_put(keyring_key);
 524
 525         return ret;
 526 }
 527 #else
 528 #include <keyutils.h>
 529
 530 static int __bch2_request_key(char *key_description, struct bch_key *key)
 531 {
 532         key_serial_t key_id;
 533
 534         key_id = request_key("user", key_description, NULL,
 535                              KEY_SPEC_USER_KEYRING);
 536         if (key_id < 0)
 537                 return -errno;
 538
 539         if (keyctl_read(key_id, (void *) key, sizeof(*key)) != sizeof(*key))
 540                 return -1;
 541
 542         return 0;
 543 }
 544 #endif
 545
 546 int bch2_request_key(struct bch_sb *sb, struct bch_key *key)
 547 {
 548         struct printbuf key_description = PRINTBUF;
 549         int ret;
 550
 551         prt_printf(&key_description, "bcachefs:");
 552         pr_uuid(&key_description, sb->user_uuid.b);
 553
 554         ret = __bch2_request_key(key_description.buf, key);
 555         printbuf_exit(&key_description);
 556         return ret;
 557 }
 558
 559 int bch2_decrypt_sb_key(struct bch_fs *c,
 560                         struct bch_sb_field_crypt *crypt,
 561                         struct bch_key *key)
 562 {
 563         struct bch_encrypted_key sb_key = crypt->key;
 564         struct bch_key user_key;
 565         int ret = 0;
 566
 567         /* is key encrypted? */
 568         if (!bch2_key_is_encrypted(&sb_key))
 569                 goto out;
 570
 571         ret = bch2_request_key(c->disk_sb.sb, &user_key);
 572         if (ret) {
 573                 bch_err(c, "error requesting encryption key: %s", bch2_err_str(ret));
 574                 goto err;
 575         }
 576
 577         /* decrypt real key: */
 578         ret = bch2_chacha_encrypt_key(&user_key, bch2_sb_key_nonce(c),
 579                              &sb_key, sizeof(sb_key));
 580         if (ret)
 581                 goto err;
 582
 583         if (bch2_key_is_encrypted(&sb_key)) {
 584                 bch_err(c, "incorrect encryption key");
 585                 ret = -EINVAL;
 586                 goto err;
 587         }
 588 out:
 589         *key = sb_key.key;
 590 err:
 591         memzero_explicit(&sb_key, sizeof(sb_key));
 592         memzero_explicit(&user_key, sizeof(user_key));
 593         return ret;
 594 }
 595
 596 static int bch2_alloc_ciphers(struct bch_fs *c)
 597 {
 598         int ret;
 599
 600         if (!c->chacha20)
 601                 c->chacha20 = crypto_alloc_sync_skcipher("chacha20", 0, 0);
 602         ret = PTR_ERR_OR_ZERO(c->chacha20);
 603
 604         if (ret) {
 605                 bch_err(c, "error requesting chacha20 module: %s", bch2_err_str(ret));
 606                 return ret;
 607         }
 608
 609         if (!c->poly1305)
 610                 c->poly1305 = crypto_alloc_shash("poly1305", 0, 0);
 611         ret = PTR_ERR_OR_ZERO(c->poly1305);
 612
 613         if (ret) {
 614                 bch_err(c, "error requesting poly1305 module: %s", bch2_err_str(ret));
 615                 return ret;
 616         }
 617
 618         return 0;
 619 }
 620
 621 int bch2_disable_encryption(struct bch_fs *c)
 622 {
 623         struct bch_sb_field_crypt *crypt;
 624         struct bch_key key;
 625         int ret = -EINVAL;
 626
 627         mutex_lock(&c->sb_lock);
 628
 629         crypt = bch2_sb_get_crypt(c->disk_sb.sb);
 630         if (!crypt)
 631                 goto out;
 632
 633         /* is key encrypted? */
 634         ret = 0;
 635         if (bch2_key_is_encrypted(&crypt->key))
 636                 goto out;
 637
 638         ret = bch2_decrypt_sb_key(c, crypt, &key);
 639         if (ret)
 640                 goto out;
 641
 642         crypt->key.magic        = cpu_to_le64(BCH_KEY_MAGIC);
 643         crypt->key.key          = key;
 644
 645         SET_BCH_SB_ENCRYPTION_TYPE(c->disk_sb.sb, 0);
 646         bch2_write_super(c);
 647 out:
 648         mutex_unlock(&c->sb_lock);
 649
 650         return ret;
 651 }
 652
 653 int bch2_enable_encryption(struct bch_fs *c, bool keyed)
 654 {
 655         struct bch_encrypted_key key;
 656         struct bch_key user_key;
 657         struct bch_sb_field_crypt *crypt;
 658         int ret = -EINVAL;
 659
 660         mutex_lock(&c->sb_lock);
 661
 662         /* Do we already have an encryption key? */
 663         if (bch2_sb_get_crypt(c->disk_sb.sb))
 664                 goto err;
 665
 666         ret = bch2_alloc_ciphers(c);
 667         if (ret)
 668                 goto err;
 669
 670         key.magic = cpu_to_le64(BCH_KEY_MAGIC);
 671         get_random_bytes(&key.key, sizeof(key.key));
 672
 673         if (keyed) {
 674                 ret = bch2_request_key(c->disk_sb.sb, &user_key);
 675                 if (ret) {
 676                         bch_err(c, "error requesting encryption key: %s", bch2_err_str(ret));
 677                         goto err;
 678                 }
 679
 680                 ret = bch2_chacha_encrypt_key(&user_key, bch2_sb_key_nonce(c),
 681                                               &key, sizeof(key));
 682                 if (ret)
 683                         goto err;
 684         }
 685
 686         ret = crypto_skcipher_setkey(&c->chacha20->base,
 687                         (void *) &key.key, sizeof(key.key));
 688         if (ret)
 689                 goto err;
 690
 691         crypt = bch2_sb_resize_crypt(&c->disk_sb, sizeof(*crypt) / sizeof(u64));
 692         if (!crypt) {
 693                 ret = -BCH_ERR_ENOSPC_sb_crypt;
 694                 goto err;
 695         }
 696
 697         crypt->key = key;
 698
 699         /* write superblock */
 700         SET_BCH_SB_ENCRYPTION_TYPE(c->disk_sb.sb, 1);
 701         bch2_write_super(c);
 702 err:
 703         mutex_unlock(&c->sb_lock);
 704         memzero_explicit(&user_key, sizeof(user_key));
 705         memzero_explicit(&key, sizeof(key));
 706         return ret;
 707 }
 708
 709 void bch2_fs_encryption_exit(struct bch_fs *c)
 710 {
 711         if (!IS_ERR_OR_NULL(c->poly1305))
 712                 crypto_free_shash(c->poly1305);
 713         if (!IS_ERR_OR_NULL(c->chacha20))
 714                 crypto_free_sync_skcipher(c->chacha20);
 715         if (!IS_ERR_OR_NULL(c->sha256))
 716                 crypto_free_shash(c->sha256);
 717 }
 718
 719 int bch2_fs_encryption_init(struct bch_fs *c)
 720 {
 721         struct bch_sb_field_crypt *crypt;
 722         struct bch_key key;
 723         int ret = 0;
 724
 725         c->sha256 = crypto_alloc_shash("sha256", 0, 0);
 726         ret = PTR_ERR_OR_ZERO(c->sha256);
 727         if (ret) {
 728                 bch_err(c, "error requesting sha256 module: %s", bch2_err_str(ret));
 729                 goto out;
 730         }
 731
 732         crypt = bch2_sb_get_crypt(c->disk_sb.sb);
 733         if (!crypt)
 734                 goto out;
 735
 736         ret = bch2_alloc_ciphers(c);
 737         if (ret)
 738                 goto out;
 739
 740         ret = bch2_decrypt_sb_key(c, crypt, &key);
 741         if (ret)
 742                 goto out;
 743
 744         ret = crypto_skcipher_setkey(&c->chacha20->base,
 745                         (void *) &key.key, sizeof(key.key));
 746         if (ret)
 747                 goto out;
 748 out:
 749         memzero_explicit(&key, sizeof(key));
 750         return ret;
 751 }