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_local_page(bv.bv_page) + bv.bv_offset;
 269
 270                         bch2_checksum_update(&state, p, bv.bv_len);
 271                         kunmap_local(p);
 272                 }
 273 #else
 274                 __bio_for_each_bvec(bv, bio, *iter, *iter)
 275                         bch2_checksum_update(&state, page_address(bv.bv_page) + bv.bv_offset,
 276                                 bv.bv_len);
 277 #endif
 278                 return (struct bch_csum) { .lo = cpu_to_le64(bch2_checksum_final(&state)) };
 279         }
 280
 281         case BCH_CSUM_chacha20_poly1305_80:
 282         case BCH_CSUM_chacha20_poly1305_128: {
 283                 SHASH_DESC_ON_STACK(desc, c->poly1305);
 284                 u8 digest[POLY1305_DIGEST_SIZE];
 285                 struct bch_csum ret = { 0 };
 286
 287                 gen_poly_key(c, desc, nonce);
 288
 289 #ifdef CONFIG_HIGHMEM
 290                 __bio_for_each_segment(bv, bio, *iter, *iter) {
 291                         void *p = kmap_local_page(bv.bv_page) + bv.bv_offset;
 292
 293                         crypto_shash_update(desc, p, bv.bv_len);
 294                         kunmap_local(p);
 295                 }
 296 #else
 297                 __bio_for_each_bvec(bv, bio, *iter, *iter)
 298                         crypto_shash_update(desc,
 299                                 page_address(bv.bv_page) + bv.bv_offset,
 300                                 bv.bv_len);
 301 #endif
 302                 crypto_shash_final(desc, digest);
 303
 304                 memcpy(&ret, digest, bch_crc_bytes[type]);
 305                 return ret;
 306         }
 307         default:
 308                 BUG();
 309         }
 310 }
 311
 312 struct bch_csum bch2_checksum_bio(struct bch_fs *c, unsigned type,
 313                                   struct nonce nonce, struct bio *bio)
 314 {
 315         struct bvec_iter iter = bio->bi_iter;
 316
 317         return __bch2_checksum_bio(c, type, nonce, bio, &iter);
 318 }
 319
 320 int __bch2_encrypt_bio(struct bch_fs *c, unsigned type,
 321                      struct nonce nonce, struct bio *bio)
 322 {
 323         struct bio_vec bv;
 324         struct bvec_iter iter;
 325         struct scatterlist sgl[16], *sg = sgl;
 326         size_t bytes = 0;
 327         int ret = 0;
 328
 329         if (!bch2_csum_type_is_encryption(type))
 330                 return 0;
 331
 332         sg_init_table(sgl, ARRAY_SIZE(sgl));
 333
 334         bio_for_each_segment(bv, bio, iter) {
 335                 if (sg == sgl + ARRAY_SIZE(sgl)) {
 336                         sg_mark_end(sg - 1);
 337
 338                         ret = do_encrypt_sg(c->chacha20, nonce, sgl, bytes);
 339                         if (ret)
 340                                 return ret;
 341
 342                         nonce = nonce_add(nonce, bytes);
 343                         bytes = 0;
 344
 345                         sg_init_table(sgl, ARRAY_SIZE(sgl));
 346                         sg = sgl;
 347                 }
 348
 349                 sg_set_page(sg++, bv.bv_page, bv.bv_len, bv.bv_offset);
 350                 bytes += bv.bv_len;
 351         }
 352
 353         sg_mark_end(sg - 1);
 354         return do_encrypt_sg(c->chacha20, nonce, sgl, bytes);
 355 }
 356
 357 struct bch_csum bch2_checksum_merge(unsigned type, struct bch_csum a,
 358                                     struct bch_csum b, size_t b_len)
 359 {
 360         struct bch2_checksum_state state;
 361
 362         state.type = type;
 363         bch2_checksum_init(&state);
 364         state.seed = (u64 __force) a.lo;
 365
 366         BUG_ON(!bch2_checksum_mergeable(type));
 367
 368         while (b_len) {
 369                 unsigned b = min_t(unsigned, b_len, PAGE_SIZE);
 370
 371                 bch2_checksum_update(&state,
 372                                 page_address(ZERO_PAGE(0)), b);
 373                 b_len -= b;
 374         }
 375         a.lo = (__le64 __force) bch2_checksum_final(&state);
 376         a.lo ^= b.lo;
 377         a.hi ^= b.hi;
 378         return a;
 379 }
 380
 381 int bch2_rechecksum_bio(struct bch_fs *c, struct bio *bio,
 382                         struct bversion version,
 383                         struct bch_extent_crc_unpacked crc_old,
 384                         struct bch_extent_crc_unpacked *crc_a,
 385                         struct bch_extent_crc_unpacked *crc_b,
 386                         unsigned len_a, unsigned len_b,
 387                         unsigned new_csum_type)
 388 {
 389         struct bvec_iter iter = bio->bi_iter;
 390         struct nonce nonce = extent_nonce(version, crc_old);
 391         struct bch_csum merged = { 0 };
 392         struct crc_split {
 393                 struct bch_extent_crc_unpacked  *crc;
 394                 unsigned                        len;
 395                 unsigned                        csum_type;
 396                 struct bch_csum                 csum;
 397         } splits[3] = {
 398                 { crc_a, len_a, new_csum_type },
 399                 { crc_b, len_b, new_csum_type },
 400                 { NULL,  bio_sectors(bio) - len_a - len_b, new_csum_type },
 401         }, *i;
 402         bool mergeable = crc_old.csum_type == new_csum_type &&
 403                 bch2_checksum_mergeable(new_csum_type);
 404         unsigned crc_nonce = crc_old.nonce;
 405
 406         BUG_ON(len_a + len_b > bio_sectors(bio));
 407         BUG_ON(crc_old.uncompressed_size != bio_sectors(bio));
 408         BUG_ON(crc_is_compressed(crc_old));
 409         BUG_ON(bch2_csum_type_is_encryption(crc_old.csum_type) !=
 410                bch2_csum_type_is_encryption(new_csum_type));
 411
 412         for (i = splits; i < splits + ARRAY_SIZE(splits); i++) {
 413                 iter.bi_size = i->len << 9;
 414                 if (mergeable || i->crc)
 415                         i->csum = __bch2_checksum_bio(c, i->csum_type,
 416                                                       nonce, bio, &iter);
 417                 else
 418                         bio_advance_iter(bio, &iter, i->len << 9);
 419                 nonce = nonce_add(nonce, i->len << 9);
 420         }
 421
 422         if (mergeable)
 423                 for (i = splits; i < splits + ARRAY_SIZE(splits); i++)
 424                         merged = bch2_checksum_merge(new_csum_type, merged,
 425                                                      i->csum, i->len << 9);
 426         else
 427                 merged = bch2_checksum_bio(c, crc_old.csum_type,
 428                                 extent_nonce(version, crc_old), bio);
 429
 430         if (bch2_crc_cmp(merged, crc_old.csum) && !c->opts.no_data_io) {
 431                 bch_err(c, "checksum error in %s() (memory corruption or bug?)\n"
 432                         "expected %0llx:%0llx got %0llx:%0llx (old type %s new type %s)",
 433                         __func__,
 434                         crc_old.csum.hi,
 435                         crc_old.csum.lo,
 436                         merged.hi,
 437                         merged.lo,
 438                         bch2_csum_types[crc_old.csum_type],
 439                         bch2_csum_types[new_csum_type]);
 440                 return -EIO;
 441         }
 442
 443         for (i = splits; i < splits + ARRAY_SIZE(splits); i++) {
 444                 if (i->crc)
 445                         *i->crc = (struct bch_extent_crc_unpacked) {
 446                                 .csum_type              = i->csum_type,
 447                                 .compression_type       = crc_old.compression_type,
 448                                 .compressed_size        = i->len,
 449                                 .uncompressed_size      = i->len,
 450                                 .offset                 = 0,
 451                                 .live_size              = i->len,
 452                                 .nonce                  = crc_nonce,
 453                                 .csum                   = i->csum,
 454                         };
 455
 456                 if (bch2_csum_type_is_encryption(new_csum_type))
 457                         crc_nonce += i->len;
 458         }
 459
 460         return 0;
 461 }
 462
 463 /* BCH_SB_FIELD_crypt: */
 464
 465 static int bch2_sb_crypt_validate(struct bch_sb *sb,
 466                                   struct bch_sb_field *f,
 467                                   struct printbuf *err)
 468 {
 469         struct bch_sb_field_crypt *crypt = field_to_type(f, crypt);
 470
 471         if (vstruct_bytes(&crypt->field) < sizeof(*crypt)) {
 472                 prt_printf(err, "wrong size (got %zu should be %zu)",
 473                        vstruct_bytes(&crypt->field), sizeof(*crypt));
 474                 return -BCH_ERR_invalid_sb_crypt;
 475         }
 476
 477         if (BCH_CRYPT_KDF_TYPE(crypt)) {
 478                 prt_printf(err, "bad kdf type %llu", BCH_CRYPT_KDF_TYPE(crypt));
 479                 return -BCH_ERR_invalid_sb_crypt;
 480         }
 481
 482         return 0;
 483 }
 484
 485 static void bch2_sb_crypt_to_text(struct printbuf *out, struct bch_sb *sb,
 486                                   struct bch_sb_field *f)
 487 {
 488         struct bch_sb_field_crypt *crypt = field_to_type(f, crypt);
 489
 490         prt_printf(out, "KFD:               %llu", BCH_CRYPT_KDF_TYPE(crypt));
 491         prt_newline(out);
 492         prt_printf(out, "scrypt n:          %llu", BCH_KDF_SCRYPT_N(crypt));
 493         prt_newline(out);
 494         prt_printf(out, "scrypt r:          %llu", BCH_KDF_SCRYPT_R(crypt));
 495         prt_newline(out);
 496         prt_printf(out, "scrypt p:          %llu", BCH_KDF_SCRYPT_P(crypt));
 497         prt_newline(out);
 498 }
 499
 500 const struct bch_sb_field_ops bch_sb_field_ops_crypt = {
 501         .validate       = bch2_sb_crypt_validate,
 502         .to_text        = bch2_sb_crypt_to_text,
 503 };
 504
 505 #ifdef __KERNEL__
 506 static int __bch2_request_key(char *key_description, struct bch_key *key)
 507 {
 508         struct key *keyring_key;
 509         const struct user_key_payload *ukp;
 510         int ret;
 511
 512         keyring_key = request_key(&key_type_user, key_description, NULL);
 513         if (IS_ERR(keyring_key))
 514                 return PTR_ERR(keyring_key);
 515
 516         down_read(&keyring_key->sem);
 517         ukp = dereference_key_locked(keyring_key);
 518         if (ukp->datalen == sizeof(*key)) {
 519                 memcpy(key, ukp->data, ukp->datalen);
 520                 ret = 0;
 521         } else {
 522                 ret = -EINVAL;
 523         }
 524         up_read(&keyring_key->sem);
 525         key_put(keyring_key);
 526
 527         return ret;
 528 }
 529 #else
 530 #include <keyutils.h>
 531
 532 static int __bch2_request_key(char *key_description, struct bch_key *key)
 533 {
 534         key_serial_t key_id;
 535
 536         key_id = request_key("user", key_description, NULL,
 537                              KEY_SPEC_USER_KEYRING);
 538         if (key_id < 0)
 539                 return -errno;
 540
 541         if (keyctl_read(key_id, (void *) key, sizeof(*key)) != sizeof(*key))
 542                 return -1;
 543
 544         return 0;
 545 }
 546 #endif
 547
 548 int bch2_request_key(struct bch_sb *sb, struct bch_key *key)
 549 {
 550         struct printbuf key_description = PRINTBUF;
 551         int ret;
 552
 553         prt_printf(&key_description, "bcachefs:");
 554         pr_uuid(&key_description, sb->user_uuid.b);
 555
 556         ret = __bch2_request_key(key_description.buf, key);
 557         printbuf_exit(&key_description);
 558         return ret;
 559 }
 560
 561 int bch2_decrypt_sb_key(struct bch_fs *c,
 562                         struct bch_sb_field_crypt *crypt,
 563                         struct bch_key *key)
 564 {
 565         struct bch_encrypted_key sb_key = crypt->key;
 566         struct bch_key user_key;
 567         int ret = 0;
 568
 569         /* is key encrypted? */
 570         if (!bch2_key_is_encrypted(&sb_key))
 571                 goto out;
 572
 573         ret = bch2_request_key(c->disk_sb.sb, &user_key);
 574         if (ret) {
 575                 bch_err(c, "error requesting encryption key: %s", bch2_err_str(ret));
 576                 goto err;
 577         }
 578
 579         /* decrypt real key: */
 580         ret = bch2_chacha_encrypt_key(&user_key, bch2_sb_key_nonce(c),
 581                              &sb_key, sizeof(sb_key));
 582         if (ret)
 583                 goto err;
 584
 585         if (bch2_key_is_encrypted(&sb_key)) {
 586                 bch_err(c, "incorrect encryption key");
 587                 ret = -EINVAL;
 588                 goto err;
 589         }
 590 out:
 591         *key = sb_key.key;
 592 err:
 593         memzero_explicit(&sb_key, sizeof(sb_key));
 594         memzero_explicit(&user_key, sizeof(user_key));
 595         return ret;
 596 }
 597
 598 static int bch2_alloc_ciphers(struct bch_fs *c)
 599 {
 600         int ret;
 601
 602         if (!c->chacha20)
 603                 c->chacha20 = crypto_alloc_sync_skcipher("chacha20", 0, 0);
 604         ret = PTR_ERR_OR_ZERO(c->chacha20);
 605
 606         if (ret) {
 607                 bch_err(c, "error requesting chacha20 module: %s", bch2_err_str(ret));
 608                 return ret;
 609         }
 610
 611         if (!c->poly1305)
 612                 c->poly1305 = crypto_alloc_shash("poly1305", 0, 0);
 613         ret = PTR_ERR_OR_ZERO(c->poly1305);
 614
 615         if (ret) {
 616                 bch_err(c, "error requesting poly1305 module: %s", bch2_err_str(ret));
 617                 return ret;
 618         }
 619
 620         return 0;
 621 }
 622
 623 int bch2_disable_encryption(struct bch_fs *c)
 624 {
 625         struct bch_sb_field_crypt *crypt;
 626         struct bch_key key;
 627         int ret = -EINVAL;
 628
 629         mutex_lock(&c->sb_lock);
 630
 631         crypt = bch2_sb_get_crypt(c->disk_sb.sb);
 632         if (!crypt)
 633                 goto out;
 634
 635         /* is key encrypted? */
 636         ret = 0;
 637         if (bch2_key_is_encrypted(&crypt->key))
 638                 goto out;
 639
 640         ret = bch2_decrypt_sb_key(c, crypt, &key);
 641         if (ret)
 642                 goto out;
 643
 644         crypt->key.magic        = cpu_to_le64(BCH_KEY_MAGIC);
 645         crypt->key.key          = key;
 646
 647         SET_BCH_SB_ENCRYPTION_TYPE(c->disk_sb.sb, 0);
 648         bch2_write_super(c);
 649 out:
 650         mutex_unlock(&c->sb_lock);
 651
 652         return ret;
 653 }
 654
 655 int bch2_enable_encryption(struct bch_fs *c, bool keyed)
 656 {
 657         struct bch_encrypted_key key;
 658         struct bch_key user_key;
 659         struct bch_sb_field_crypt *crypt;
 660         int ret = -EINVAL;
 661
 662         mutex_lock(&c->sb_lock);
 663
 664         /* Do we already have an encryption key? */
 665         if (bch2_sb_get_crypt(c->disk_sb.sb))
 666                 goto err;
 667
 668         ret = bch2_alloc_ciphers(c);
 669         if (ret)
 670                 goto err;
 671
 672         key.magic = cpu_to_le64(BCH_KEY_MAGIC);
 673         get_random_bytes(&key.key, sizeof(key.key));
 674
 675         if (keyed) {
 676                 ret = bch2_request_key(c->disk_sb.sb, &user_key);
 677                 if (ret) {
 678                         bch_err(c, "error requesting encryption key: %s", bch2_err_str(ret));
 679                         goto err;
 680                 }
 681
 682                 ret = bch2_chacha_encrypt_key(&user_key, bch2_sb_key_nonce(c),
 683                                               &key, sizeof(key));
 684                 if (ret)
 685                         goto err;
 686         }
 687
 688         ret = crypto_skcipher_setkey(&c->chacha20->base,
 689                         (void *) &key.key, sizeof(key.key));
 690         if (ret)
 691                 goto err;
 692
 693         crypt = bch2_sb_resize_crypt(&c->disk_sb, sizeof(*crypt) / sizeof(u64));
 694         if (!crypt) {
 695                 ret = -BCH_ERR_ENOSPC_sb_crypt;
 696                 goto err;
 697         }
 698
 699         crypt->key = key;
 700
 701         /* write superblock */
 702         SET_BCH_SB_ENCRYPTION_TYPE(c->disk_sb.sb, 1);
 703         bch2_write_super(c);
 704 err:
 705         mutex_unlock(&c->sb_lock);
 706         memzero_explicit(&user_key, sizeof(user_key));
 707         memzero_explicit(&key, sizeof(key));
 708         return ret;
 709 }
 710
 711 void bch2_fs_encryption_exit(struct bch_fs *c)
 712 {
 713         if (!IS_ERR_OR_NULL(c->poly1305))
 714                 crypto_free_shash(c->poly1305);
 715         if (!IS_ERR_OR_NULL(c->chacha20))
 716                 crypto_free_sync_skcipher(c->chacha20);
 717         if (!IS_ERR_OR_NULL(c->sha256))
 718                 crypto_free_shash(c->sha256);
 719 }
 720
 721 int bch2_fs_encryption_init(struct bch_fs *c)
 722 {
 723         struct bch_sb_field_crypt *crypt;
 724         struct bch_key key;
 725         int ret = 0;
 726
 727         c->sha256 = crypto_alloc_shash("sha256", 0, 0);
 728         ret = PTR_ERR_OR_ZERO(c->sha256);
 729         if (ret) {
 730                 bch_err(c, "error requesting sha256 module: %s", bch2_err_str(ret));
 731                 goto out;
 732         }
 733
 734         crypt = bch2_sb_get_crypt(c->disk_sb.sb);
 735         if (!crypt)
 736                 goto out;
 737
 738         ret = bch2_alloc_ciphers(c);
 739         if (ret)
 740                 goto out;
 741
 742         ret = bch2_decrypt_sb_key(c, crypt, &key);
 743         if (ret)
 744                 goto out;
 745
 746         ret = crypto_skcipher_setkey(&c->chacha20->base,
 747                         (void *) &key.key, sizeof(key.key));
 748         if (ret)
 749                 goto out;
 750 out:
 751         memzero_explicit(&key, sizeof(key));
 752         return ret;
 753 }