fs/bcachefs/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_callback(req, 0, NULL, NULL);
 106         skcipher_request_set_crypt(req, sg, sg, len, nonce.d);
 107
 108         ret = crypto_skcipher_encrypt(req);
 109         if (ret)
 110                 pr_err("got error %i from crypto_skcipher_encrypt()", ret);
 111
 112         return ret;
 113 }
 114
 115 static inline int do_encrypt(struct crypto_sync_skcipher *tfm,
 116                               struct nonce nonce,
 117                               void *buf, size_t len)
 118 {
 119         if (!is_vmalloc_addr(buf)) {
 120                 struct scatterlist sg;
 121
 122                 sg_init_table(&sg, 1);
 123                 sg_set_page(&sg,
 124                             is_vmalloc_addr(buf)
 125                             ? vmalloc_to_page(buf)
 126                             : virt_to_page(buf),
 127                             len, offset_in_page(buf));
 128                 return do_encrypt_sg(tfm, nonce, &sg, len);
 129         } else {
 130                 unsigned pages = buf_pages(buf, len);
 131                 struct scatterlist *sg;
 132                 size_t orig_len = len;
 133                 int ret, i;
 134
 135                 sg = kmalloc_array(pages, sizeof(*sg), GFP_KERNEL);
 136                 if (!sg)
 137                         return -BCH_ERR_ENOMEM_do_encrypt;
 138
 139                 sg_init_table(sg, pages);
 140
 141                 for (i = 0; i < pages; i++) {
 142                         unsigned offset = offset_in_page(buf);
 143                         unsigned pg_len = min_t(size_t, len, PAGE_SIZE - offset);
 144
 145                         sg_set_page(sg + i, vmalloc_to_page(buf), pg_len, offset);
 146                         buf += pg_len;
 147                         len -= pg_len;
 148                 }
 149
 150                 ret = do_encrypt_sg(tfm, nonce, sg, orig_len);
 151                 kfree(sg);
 152                 return ret;
 153         }
 154 }
 155
 156 int bch2_chacha_encrypt_key(struct bch_key *key, struct nonce nonce,
 157                             void *buf, size_t len)
 158 {
 159         struct crypto_sync_skcipher *chacha20 =
 160                 crypto_alloc_sync_skcipher("chacha20", 0, 0);
 161         int ret;
 162
 163         ret = PTR_ERR_OR_ZERO(chacha20);
 164         if (ret) {
 165                 pr_err("error requesting chacha20 cipher: %s", bch2_err_str(ret));
 166                 return ret;
 167         }
 168
 169         ret = crypto_skcipher_setkey(&chacha20->base,
 170                                      (void *) key, sizeof(*key));
 171         if (ret) {
 172                 pr_err("error from crypto_skcipher_setkey(): %s", bch2_err_str(ret));
 173                 goto err;
 174         }
 175
 176         ret = do_encrypt(chacha20, nonce, buf, len);
 177 err:
 178         crypto_free_sync_skcipher(chacha20);
 179         return ret;
 180 }
 181
 182 static int gen_poly_key(struct bch_fs *c, struct shash_desc *desc,
 183                         struct nonce nonce)
 184 {
 185         u8 key[POLY1305_KEY_SIZE];
 186         int ret;
 187
 188         nonce.d[3] ^= BCH_NONCE_POLY;
 189
 190         memset(key, 0, sizeof(key));
 191         ret = do_encrypt(c->chacha20, nonce, key, sizeof(key));
 192         if (ret)
 193                 return ret;
 194
 195         desc->tfm = c->poly1305;
 196         crypto_shash_init(desc);
 197         crypto_shash_update(desc, key, sizeof(key));
 198         return 0;
 199 }
 200
 201 struct bch_csum bch2_checksum(struct bch_fs *c, unsigned type,
 202                               struct nonce nonce, const void *data, size_t len)
 203 {
 204         switch (type) {
 205         case BCH_CSUM_none:
 206         case BCH_CSUM_crc32c_nonzero:
 207         case BCH_CSUM_crc64_nonzero:
 208         case BCH_CSUM_crc32c:
 209         case BCH_CSUM_xxhash:
 210         case BCH_CSUM_crc64: {
 211                 struct bch2_checksum_state state;
 212
 213                 state.type = type;
 214
 215                 bch2_checksum_init(&state);
 216                 bch2_checksum_update(&state, data, len);
 217
 218                 return (struct bch_csum) { .lo = cpu_to_le64(bch2_checksum_final(&state)) };
 219         }
 220
 221         case BCH_CSUM_chacha20_poly1305_80:
 222         case BCH_CSUM_chacha20_poly1305_128: {
 223                 SHASH_DESC_ON_STACK(desc, c->poly1305);
 224                 u8 digest[POLY1305_DIGEST_SIZE];
 225                 struct bch_csum ret = { 0 };
 226
 227                 gen_poly_key(c, desc, nonce);
 228
 229                 crypto_shash_update(desc, data, len);
 230                 crypto_shash_final(desc, digest);
 231
 232                 memcpy(&ret, digest, bch_crc_bytes[type]);
 233                 return ret;
 234         }
 235         default:
 236                 BUG();
 237         }
 238 }
 239
 240 int bch2_encrypt(struct bch_fs *c, unsigned type,
 241                   struct nonce nonce, void *data, size_t len)
 242 {
 243         if (!bch2_csum_type_is_encryption(type))
 244                 return 0;
 245
 246         return do_encrypt(c->chacha20, nonce, data, len);
 247 }
 248
 249 static struct bch_csum __bch2_checksum_bio(struct bch_fs *c, unsigned type,
 250                                            struct nonce nonce, struct bio *bio,
 251                                            struct bvec_iter *iter)
 252 {
 253         struct bio_vec bv;
 254
 255         switch (type) {
 256         case BCH_CSUM_none:
 257                 return (struct bch_csum) { 0 };
 258         case BCH_CSUM_crc32c_nonzero:
 259         case BCH_CSUM_crc64_nonzero:
 260         case BCH_CSUM_crc32c:
 261         case BCH_CSUM_xxhash:
 262         case BCH_CSUM_crc64: {
 263                 struct bch2_checksum_state state;
 264
 265                 state.type = type;
 266                 bch2_checksum_init(&state);
 267
 268 #ifdef CONFIG_HIGHMEM
 269                 __bio_for_each_segment(bv, bio, *iter, *iter) {
 270                         void *p = kmap_local_page(bv.bv_page) + bv.bv_offset;
 271
 272                         bch2_checksum_update(&state, p, bv.bv_len);
 273                         kunmap_local(p);
 274                 }
 275 #else
 276                 __bio_for_each_bvec(bv, bio, *iter, *iter)
 277                         bch2_checksum_update(&state, page_address(bv.bv_page) + bv.bv_offset,
 278                                 bv.bv_len);
 279 #endif
 280                 return (struct bch_csum) { .lo = cpu_to_le64(bch2_checksum_final(&state)) };
 281         }
 282
 283         case BCH_CSUM_chacha20_poly1305_80:
 284         case BCH_CSUM_chacha20_poly1305_128: {
 285                 SHASH_DESC_ON_STACK(desc, c->poly1305);
 286                 u8 digest[POLY1305_DIGEST_SIZE];
 287                 struct bch_csum ret = { 0 };
 288
 289                 gen_poly_key(c, desc, nonce);
 290
 291 #ifdef CONFIG_HIGHMEM
 292                 __bio_for_each_segment(bv, bio, *iter, *iter) {
 293                         void *p = kmap_local_page(bv.bv_page) + bv.bv_offset;
 294
 295                         crypto_shash_update(desc, p, bv.bv_len);
 296                         kunmap_local(p);
 297                 }
 298 #else
 299                 __bio_for_each_bvec(bv, bio, *iter, *iter)
 300                         crypto_shash_update(desc,
 301                                 page_address(bv.bv_page) + bv.bv_offset,
 302                                 bv.bv_len);
 303 #endif
 304                 crypto_shash_final(desc, digest);
 305
 306                 memcpy(&ret, digest, bch_crc_bytes[type]);
 307                 return ret;
 308         }
 309         default:
 310                 BUG();
 311         }
 312 }
 313
 314 struct bch_csum bch2_checksum_bio(struct bch_fs *c, unsigned type,
 315                                   struct nonce nonce, struct bio *bio)
 316 {
 317         struct bvec_iter iter = bio->bi_iter;
 318
 319         return __bch2_checksum_bio(c, type, nonce, bio, &iter);
 320 }
 321
 322 int __bch2_encrypt_bio(struct bch_fs *c, unsigned type,
 323                      struct nonce nonce, struct bio *bio)
 324 {
 325         struct bio_vec bv;
 326         struct bvec_iter iter;
 327         struct scatterlist sgl[16], *sg = sgl;
 328         size_t bytes = 0;
 329         int ret = 0;
 330
 331         if (!bch2_csum_type_is_encryption(type))
 332                 return 0;
 333
 334         sg_init_table(sgl, ARRAY_SIZE(sgl));
 335
 336         bio_for_each_segment(bv, bio, iter) {
 337                 if (sg == sgl + ARRAY_SIZE(sgl)) {
 338                         sg_mark_end(sg - 1);
 339
 340                         ret = do_encrypt_sg(c->chacha20, nonce, sgl, bytes);
 341                         if (ret)
 342                                 return ret;
 343
 344                         nonce = nonce_add(nonce, bytes);
 345                         bytes = 0;
 346
 347                         sg_init_table(sgl, ARRAY_SIZE(sgl));
 348                         sg = sgl;
 349                 }
 350
 351                 sg_set_page(sg++, bv.bv_page, bv.bv_len, bv.bv_offset);
 352                 bytes += bv.bv_len;
 353         }
 354
 355         sg_mark_end(sg - 1);
 356         return do_encrypt_sg(c->chacha20, nonce, sgl, bytes);
 357 }
 358
 359 struct bch_csum bch2_checksum_merge(unsigned type, struct bch_csum a,
 360                                     struct bch_csum b, size_t b_len)
 361 {
 362         struct bch2_checksum_state state;
 363
 364         state.type = type;
 365         bch2_checksum_init(&state);
 366         state.seed = le64_to_cpu(a.lo);
 367
 368         BUG_ON(!bch2_checksum_mergeable(type));
 369
 370         while (b_len) {
 371                 unsigned page_len = min_t(unsigned, b_len, PAGE_SIZE);
 372
 373                 bch2_checksum_update(&state,
 374                                 page_address(ZERO_PAGE(0)), page_len);
 375                 b_len -= page_len;
 376         }
 377         a.lo = cpu_to_le64(bch2_checksum_final(&state));
 378         a.lo ^= b.lo;
 379         a.hi ^= b.hi;
 380         return a;
 381 }
 382
 383 int bch2_rechecksum_bio(struct bch_fs *c, struct bio *bio,
 384                         struct bversion version,
 385                         struct bch_extent_crc_unpacked crc_old,
 386                         struct bch_extent_crc_unpacked *crc_a,
 387                         struct bch_extent_crc_unpacked *crc_b,
 388                         unsigned len_a, unsigned len_b,
 389                         unsigned new_csum_type)
 390 {
 391         struct bvec_iter iter = bio->bi_iter;
 392         struct nonce nonce = extent_nonce(version, crc_old);
 393         struct bch_csum merged = { 0 };
 394         struct crc_split {
 395                 struct bch_extent_crc_unpacked  *crc;
 396                 unsigned                        len;
 397                 unsigned                        csum_type;
 398                 struct bch_csum                 csum;
 399         } splits[3] = {
 400                 { crc_a, len_a, new_csum_type, { 0 }},
 401                 { crc_b, len_b, new_csum_type, { 0 } },
 402                 { NULL,  bio_sectors(bio) - len_a - len_b, new_csum_type, { 0 } },
 403         }, *i;
 404         bool mergeable = crc_old.csum_type == new_csum_type &&
 405                 bch2_checksum_mergeable(new_csum_type);
 406         unsigned crc_nonce = crc_old.nonce;
 407
 408         BUG_ON(len_a + len_b > bio_sectors(bio));
 409         BUG_ON(crc_old.uncompressed_size != bio_sectors(bio));
 410         BUG_ON(crc_is_compressed(crc_old));
 411         BUG_ON(bch2_csum_type_is_encryption(crc_old.csum_type) !=
 412                bch2_csum_type_is_encryption(new_csum_type));
 413
 414         for (i = splits; i < splits + ARRAY_SIZE(splits); i++) {
 415                 iter.bi_size = i->len << 9;
 416                 if (mergeable || i->crc)
 417                         i->csum = __bch2_checksum_bio(c, i->csum_type,
 418                                                       nonce, bio, &iter);
 419                 else
 420                         bio_advance_iter(bio, &iter, i->len << 9);
 421                 nonce = nonce_add(nonce, i->len << 9);
 422         }
 423
 424         if (mergeable)
 425                 for (i = splits; i < splits + ARRAY_SIZE(splits); i++)
 426                         merged = bch2_checksum_merge(new_csum_type, merged,
 427                                                      i->csum, i->len << 9);
 428         else
 429                 merged = bch2_checksum_bio(c, crc_old.csum_type,
 430                                 extent_nonce(version, crc_old), bio);
 431
 432         if (bch2_crc_cmp(merged, crc_old.csum) && !c->opts.no_data_io) {
 433                 struct printbuf buf = PRINTBUF;
 434                 prt_printf(&buf, "checksum error in %s() (memory corruption or bug?)\n"
 435                            "expected %0llx:%0llx got %0llx:%0llx (old type ",
 436                            __func__,
 437                            crc_old.csum.hi,
 438                            crc_old.csum.lo,
 439                            merged.hi,
 440                            merged.lo);
 441                 bch2_prt_csum_type(&buf, crc_old.csum_type);
 442                 prt_str(&buf, " new type ");
 443                 bch2_prt_csum_type(&buf, new_csum_type);
 444                 prt_str(&buf, ")");
 445                 bch_err(c, "%s", buf.buf);
 446                 printbuf_exit(&buf);
 447                 return -EIO;
 448         }
 449
 450         for (i = splits; i < splits + ARRAY_SIZE(splits); i++) {
 451                 if (i->crc)
 452                         *i->crc = (struct bch_extent_crc_unpacked) {
 453                                 .csum_type              = i->csum_type,
 454                                 .compression_type       = crc_old.compression_type,
 455                                 .compressed_size        = i->len,
 456                                 .uncompressed_size      = i->len,
 457                                 .offset                 = 0,
 458                                 .live_size              = i->len,
 459                                 .nonce                  = crc_nonce,
 460                                 .csum                   = i->csum,
 461                         };
 462
 463                 if (bch2_csum_type_is_encryption(new_csum_type))
 464                         crc_nonce += i->len;
 465         }
 466
 467         return 0;
 468 }
 469
 470 /* BCH_SB_FIELD_crypt: */
 471
 472 static int bch2_sb_crypt_validate(struct bch_sb *sb,
 473                                   struct bch_sb_field *f,
 474                                   struct printbuf *err)
 475 {
 476         struct bch_sb_field_crypt *crypt = field_to_type(f, crypt);
 477
 478         if (vstruct_bytes(&crypt->field) < sizeof(*crypt)) {
 479                 prt_printf(err, "wrong size (got %zu should be %zu)",
 480                        vstruct_bytes(&crypt->field), sizeof(*crypt));
 481                 return -BCH_ERR_invalid_sb_crypt;
 482         }
 483
 484         if (BCH_CRYPT_KDF_TYPE(crypt)) {
 485                 prt_printf(err, "bad kdf type %llu", BCH_CRYPT_KDF_TYPE(crypt));
 486                 return -BCH_ERR_invalid_sb_crypt;
 487         }
 488
 489         return 0;
 490 }
 491
 492 static void bch2_sb_crypt_to_text(struct printbuf *out, struct bch_sb *sb,
 493                                   struct bch_sb_field *f)
 494 {
 495         struct bch_sb_field_crypt *crypt = field_to_type(f, crypt);
 496
 497         prt_printf(out, "KFD:               %llu", BCH_CRYPT_KDF_TYPE(crypt));
 498         prt_newline(out);
 499         prt_printf(out, "scrypt n:          %llu", BCH_KDF_SCRYPT_N(crypt));
 500         prt_newline(out);
 501         prt_printf(out, "scrypt r:          %llu", BCH_KDF_SCRYPT_R(crypt));
 502         prt_newline(out);
 503         prt_printf(out, "scrypt p:          %llu", BCH_KDF_SCRYPT_P(crypt));
 504         prt_newline(out);
 505 }
 506
 507 const struct bch_sb_field_ops bch_sb_field_ops_crypt = {
 508         .validate       = bch2_sb_crypt_validate,
 509         .to_text        = bch2_sb_crypt_to_text,
 510 };
 511
 512 #ifdef __KERNEL__
 513 static int __bch2_request_key(char *key_description, struct bch_key *key)
 514 {
 515         struct key *keyring_key;
 516         const struct user_key_payload *ukp;
 517         int ret;
 518
 519         keyring_key = request_key(&key_type_user, key_description, NULL);
 520         if (IS_ERR(keyring_key))
 521                 return PTR_ERR(keyring_key);
 522
 523         down_read(&keyring_key->sem);
 524         ukp = dereference_key_locked(keyring_key);
 525         if (ukp->datalen == sizeof(*key)) {
 526                 memcpy(key, ukp->data, ukp->datalen);
 527                 ret = 0;
 528         } else {
 529                 ret = -EINVAL;
 530         }
 531         up_read(&keyring_key->sem);
 532         key_put(keyring_key);
 533
 534         return ret;
 535 }
 536 #else
 537 #include <keyutils.h>
 538
 539 static int __bch2_request_key(char *key_description, struct bch_key *key)
 540 {
 541         key_serial_t key_id;
 542
 543         key_id = request_key("user", key_description, NULL,
 544                              KEY_SPEC_SESSION_KEYRING);
 545         if (key_id >= 0)
 546                 goto got_key;
 547
 548         key_id = request_key("user", key_description, NULL,
 549                              KEY_SPEC_USER_KEYRING);
 550         if (key_id >= 0)
 551                 goto got_key;
 552
 553         key_id = request_key("user", key_description, NULL,
 554                              KEY_SPEC_USER_SESSION_KEYRING);
 555         if (key_id >= 0)
 556                 goto got_key;
 557
 558         return -errno;
 559 got_key:
 560
 561         if (keyctl_read(key_id, (void *) key, sizeof(*key)) != sizeof(*key))
 562                 return -1;
 563
 564         return 0;
 565 }
 566
 567 #include "crypto.h"
 568 #endif
 569
 570 int bch2_request_key(struct bch_sb *sb, struct bch_key *key)
 571 {
 572         struct printbuf key_description = PRINTBUF;
 573         int ret;
 574
 575         prt_printf(&key_description, "bcachefs:");
 576         pr_uuid(&key_description, sb->user_uuid.b);
 577
 578         ret = __bch2_request_key(key_description.buf, key);
 579         printbuf_exit(&key_description);
 580
 581 #ifndef __KERNEL__
 582         if (ret) {
 583                 char *passphrase = read_passphrase("Enter passphrase: ");
 584                 struct bch_encrypted_key sb_key;
 585
 586                 bch2_passphrase_check(sb, passphrase,
 587                                       key, &sb_key);
 588                 ret = 0;
 589         }
 590 #endif
 591
 592         /* stash with memfd, pass memfd fd to mount */
 593
 594         return ret;
 595 }
 596
 597 #ifndef __KERNEL__
 598 int bch2_revoke_key(struct bch_sb *sb)
 599 {
 600         key_serial_t key_id;
 601         struct printbuf key_description = PRINTBUF;
 602
 603         prt_printf(&key_description, "bcachefs:");
 604         pr_uuid(&key_description, sb->user_uuid.b);
 605
 606         key_id = request_key("user", key_description.buf, NULL, KEY_SPEC_USER_KEYRING);
 607         printbuf_exit(&key_description);
 608         if (key_id < 0)
 609                 return errno;
 610
 611         keyctl_revoke(key_id);
 612
 613         return 0;
 614 }
 615 #endif
 616
 617 int bch2_decrypt_sb_key(struct bch_fs *c,
 618                         struct bch_sb_field_crypt *crypt,
 619                         struct bch_key *key)
 620 {
 621         struct bch_encrypted_key sb_key = crypt->key;
 622         struct bch_key user_key;
 623         int ret = 0;
 624
 625         /* is key encrypted? */
 626         if (!bch2_key_is_encrypted(&sb_key))
 627                 goto out;
 628
 629         ret = bch2_request_key(c->disk_sb.sb, &user_key);
 630         if (ret) {
 631                 bch_err(c, "error requesting encryption key: %s", bch2_err_str(ret));
 632                 goto err;
 633         }
 634
 635         /* decrypt real key: */
 636         ret = bch2_chacha_encrypt_key(&user_key, bch2_sb_key_nonce(c),
 637                                       &sb_key, sizeof(sb_key));
 638         if (ret)
 639                 goto err;
 640
 641         if (bch2_key_is_encrypted(&sb_key)) {
 642                 bch_err(c, "incorrect encryption key");
 643                 ret = -EINVAL;
 644                 goto err;
 645         }
 646 out:
 647         *key = sb_key.key;
 648 err:
 649         memzero_explicit(&sb_key, sizeof(sb_key));
 650         memzero_explicit(&user_key, sizeof(user_key));
 651         return ret;
 652 }
 653
 654 static int bch2_alloc_ciphers(struct bch_fs *c)
 655 {
 656         int ret;
 657
 658         if (!c->chacha20)
 659                 c->chacha20 = crypto_alloc_sync_skcipher("chacha20", 0, 0);
 660         ret = PTR_ERR_OR_ZERO(c->chacha20);
 661
 662         if (ret) {
 663                 bch_err(c, "error requesting chacha20 module: %s", bch2_err_str(ret));
 664                 return ret;
 665         }
 666
 667         if (!c->poly1305)
 668                 c->poly1305 = crypto_alloc_shash("poly1305", 0, 0);
 669         ret = PTR_ERR_OR_ZERO(c->poly1305);
 670
 671         if (ret) {
 672                 bch_err(c, "error requesting poly1305 module: %s", bch2_err_str(ret));
 673                 return ret;
 674         }
 675
 676         return 0;
 677 }
 678
 679 int bch2_disable_encryption(struct bch_fs *c)
 680 {
 681         struct bch_sb_field_crypt *crypt;
 682         struct bch_key key;
 683         int ret = -EINVAL;
 684
 685         mutex_lock(&c->sb_lock);
 686
 687         crypt = bch2_sb_field_get(c->disk_sb.sb, crypt);
 688         if (!crypt)
 689                 goto out;
 690
 691         /* is key encrypted? */
 692         ret = 0;
 693         if (bch2_key_is_encrypted(&crypt->key))
 694                 goto out;
 695
 696         ret = bch2_decrypt_sb_key(c, crypt, &key);
 697         if (ret)
 698                 goto out;
 699
 700         crypt->key.magic        = cpu_to_le64(BCH_KEY_MAGIC);
 701         crypt->key.key          = key;
 702
 703         SET_BCH_SB_ENCRYPTION_TYPE(c->disk_sb.sb, 0);
 704         bch2_write_super(c);
 705 out:
 706         mutex_unlock(&c->sb_lock);
 707
 708         return ret;
 709 }
 710
 711 int bch2_enable_encryption(struct bch_fs *c, bool keyed)
 712 {
 713         struct bch_encrypted_key key;
 714         struct bch_key user_key;
 715         struct bch_sb_field_crypt *crypt;
 716         int ret = -EINVAL;
 717
 718         mutex_lock(&c->sb_lock);
 719
 720         /* Do we already have an encryption key? */
 721         if (bch2_sb_field_get(c->disk_sb.sb, crypt))
 722                 goto err;
 723
 724         ret = bch2_alloc_ciphers(c);
 725         if (ret)
 726                 goto err;
 727
 728         key.magic = cpu_to_le64(BCH_KEY_MAGIC);
 729         get_random_bytes(&key.key, sizeof(key.key));
 730
 731         if (keyed) {
 732                 ret = bch2_request_key(c->disk_sb.sb, &user_key);
 733                 if (ret) {
 734                         bch_err(c, "error requesting encryption key: %s", bch2_err_str(ret));
 735                         goto err;
 736                 }
 737
 738                 ret = bch2_chacha_encrypt_key(&user_key, bch2_sb_key_nonce(c),
 739                                               &key, sizeof(key));
 740                 if (ret)
 741                         goto err;
 742         }
 743
 744         ret = crypto_skcipher_setkey(&c->chacha20->base,
 745                         (void *) &key.key, sizeof(key.key));
 746         if (ret)
 747                 goto err;
 748
 749         crypt = bch2_sb_field_resize(&c->disk_sb, crypt,
 750                                      sizeof(*crypt) / sizeof(u64));
 751         if (!crypt) {
 752                 ret = -BCH_ERR_ENOSPC_sb_crypt;
 753                 goto err;
 754         }
 755
 756         crypt->key = key;
 757
 758         /* write superblock */
 759         SET_BCH_SB_ENCRYPTION_TYPE(c->disk_sb.sb, 1);
 760         bch2_write_super(c);
 761 err:
 762         mutex_unlock(&c->sb_lock);
 763         memzero_explicit(&user_key, sizeof(user_key));
 764         memzero_explicit(&key, sizeof(key));
 765         return ret;
 766 }
 767
 768 void bch2_fs_encryption_exit(struct bch_fs *c)
 769 {
 770         if (!IS_ERR_OR_NULL(c->poly1305))
 771                 crypto_free_shash(c->poly1305);
 772         if (!IS_ERR_OR_NULL(c->chacha20))
 773                 crypto_free_sync_skcipher(c->chacha20);
 774         if (!IS_ERR_OR_NULL(c->sha256))
 775                 crypto_free_shash(c->sha256);
 776 }
 777
 778 int bch2_fs_encryption_init(struct bch_fs *c)
 779 {
 780         struct bch_sb_field_crypt *crypt;
 781         struct bch_key key;
 782         int ret = 0;
 783
 784         c->sha256 = crypto_alloc_shash("sha256", 0, 0);
 785         ret = PTR_ERR_OR_ZERO(c->sha256);
 786         if (ret) {
 787                 bch_err(c, "error requesting sha256 module: %s", bch2_err_str(ret));
 788                 goto out;
 789         }
 790
 791         crypt = bch2_sb_field_get(c->disk_sb.sb, crypt);
 792         if (!crypt)
 793                 goto out;
 794
 795         ret = bch2_alloc_ciphers(c);
 796         if (ret)
 797                 goto out;
 798
 799         ret = bch2_decrypt_sb_key(c, crypt, &key);
 800         if (ret)
 801                 goto out;
 802
 803         ret = crypto_skcipher_setkey(&c->chacha20->base,
 804                         (void *) &key.key, sizeof(key.key));
 805         if (ret)
 806                 goto out;
 807 out:
 808         memzero_explicit(&key, sizeof(key));
 809         return ret;
 810 }