/* * Copyright (C) 2003 Jana Saout * Copyright (C) 2004 Clemens Fruhwirth * Copyright (C) 2006-2015 Red Hat, Inc. All rights reserved. * Copyright (C) 2013 Milan Broz * * This file is released under the GPL. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DM_MSG_PREFIX "crypt" /* * context holding the current state of a multi-part conversion */ struct convert_context { struct completion restart; struct bio *bio_in; struct bio *bio_out; struct bvec_iter iter_in; struct bvec_iter iter_out; sector_t cc_sector; atomic_t cc_pending; struct skcipher_request *req; }; /* * per bio private data */ struct dm_crypt_io { struct crypt_config *cc; struct bio *base_bio; struct work_struct work; struct convert_context ctx; atomic_t io_pending; int error; sector_t sector; struct rb_node rb_node; } CRYPTO_MINALIGN_ATTR; struct dm_crypt_request { struct convert_context *ctx; struct scatterlist sg_in; struct scatterlist sg_out; sector_t iv_sector; }; struct crypt_config; struct crypt_iv_operations { int (*ctr)(struct crypt_config *cc, struct dm_target *ti, const char *opts); void (*dtr)(struct crypt_config *cc); int (*init)(struct crypt_config *cc); int (*wipe)(struct crypt_config *cc); int (*generator)(struct crypt_config *cc, u8 *iv, struct dm_crypt_request *dmreq); int (*post)(struct crypt_config *cc, u8 *iv, struct dm_crypt_request *dmreq); }; struct iv_essiv_private { struct crypto_ahash *hash_tfm; u8 *salt; }; struct iv_benbi_private { int shift; }; #define LMK_SEED_SIZE 64 /* hash + 0 */ struct iv_lmk_private { struct crypto_shash *hash_tfm; u8 *seed; }; #define TCW_WHITENING_SIZE 16 struct iv_tcw_private { struct crypto_shash *crc32_tfm; u8 *iv_seed; u8 *whitening; }; struct crypto_completion { struct completion restart; int req_err; }; /* * Crypt: maps a linear range of a block device * and encrypts / decrypts at the same time. */ enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID, DM_CRYPT_SAME_CPU, DM_CRYPT_NO_OFFLOAD }; /* * The fields in here must be read only after initialization. */ struct crypt_config { struct dm_dev *dev; sector_t start; /* * pool for per bio private data, crypto requests and * encryption requeusts/buffer pages */ mempool_t *req_pool; mempool_t *page_pool; struct bio_set *bs; struct mutex bio_alloc_lock; struct workqueue_struct *io_queue; struct workqueue_struct *crypt_queue; struct task_struct *write_thread; wait_queue_head_t write_thread_wait; struct rb_root write_tree; char *cipher; char *cipher_string; struct crypt_iv_operations *iv_gen_ops; union { struct iv_essiv_private essiv; struct iv_benbi_private benbi; struct iv_lmk_private lmk; struct iv_tcw_private tcw; } iv_gen_private; sector_t iv_offset; unsigned int iv_size; /* ESSIV: struct crypto_cipher *essiv_tfm */ void *iv_private; struct crypto_skcipher **tfms; unsigned tfms_count; /* * Layout of each crypto request: * * struct skcipher_request * context * padding * struct dm_crypt_request * padding * IV * * The padding is added so that dm_crypt_request and the IV are * correctly aligned. */ unsigned int dmreq_start; unsigned int per_bio_data_size; unsigned long flags; unsigned int key_size; unsigned int key_parts; /* independent parts in key buffer */ unsigned int key_extra_size; /* additional keys length */ u8 key[0]; }; #define MIN_IOS 64 static void clone_init(struct dm_crypt_io *, struct bio *); static void kcryptd_queue_crypt(struct dm_crypt_io *io); static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq); /* * Use this to access cipher attributes that are the same for each CPU. */ static struct crypto_skcipher *any_tfm(struct crypt_config *cc) { return cc->tfms[0]; } /* * Different IV generation algorithms: * * plain: the initial vector is the 32-bit little-endian version of the sector * number, padded with zeros if necessary. * * plain64: the initial vector is the 64-bit little-endian version of the sector * number, padded with zeros if necessary. * * essiv: "encrypted sector|salt initial vector", the sector number is * encrypted with the bulk cipher using a salt as key. The salt * should be derived from the bulk cipher's key via hashing. * * benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1 * (needed for LRW-32-AES and possible other narrow block modes) * * null: the initial vector is always zero. Provides compatibility with * obsolete loop_fish2 devices. Do not use for new devices. * * lmk: Compatible implementation of the block chaining mode used * by the Loop-AES block device encryption system * designed by Jari Ruusu. See http://loop-aes.sourceforge.net/ * It operates on full 512 byte sectors and uses CBC * with an IV derived from the sector number, the data and * optionally extra IV seed. * This means that after decryption the first block * of sector must be tweaked according to decrypted data. * Loop-AES can use three encryption schemes: * version 1: is plain aes-cbc mode * version 2: uses 64 multikey scheme with lmk IV generator * version 3: the same as version 2 with additional IV seed * (it uses 65 keys, last key is used as IV seed) * * tcw: Compatible implementation of the block chaining mode used * by the TrueCrypt device encryption system (prior to version 4.1). * For more info see: https://gitlab.com/cryptsetup/cryptsetup/wikis/TrueCryptOnDiskFormat * It operates on full 512 byte sectors and uses CBC * with an IV derived from initial key and the sector number. * In addition, whitening value is applied on every sector, whitening * is calculated from initial key, sector number and mixed using CRC32. * Note that this encryption scheme is vulnerable to watermarking attacks * and should be used for old compatible containers access only. * * plumb: unimplemented, see: * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454 */ static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, struct dm_crypt_request *dmreq) { memset(iv, 0, cc->iv_size); *(__le32 *)iv = cpu_to_le32(dmreq->iv_sector & 0xffffffff); return 0; } static int crypt_iv_plain64_gen(struct crypt_config *cc, u8 *iv, struct dm_crypt_request *dmreq) { memset(iv, 0, cc->iv_size); *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector); return 0; } static void crypt_complete(struct crypto_async_request *req, int err) { struct crypto_completion *done = req->data; if (err != -EINPROGRESS) { done->req_err = err; complete(&done->restart); } } static int async_hash_op(struct ahash_request *req, struct crypto_completion *tr, int ret) { if (ret == -EBUSY || ret == -EINPROGRESS) { wait_for_completion(&tr->restart); reinit_completion(&tr->restart); ret = tr->req_err; } return ret; } /* Initialise ESSIV - compute salt but no local memory allocations */ static int crypt_iv_essiv_init(struct crypt_config *cc) { struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; AHASH_REQUEST_ON_STACK(req, essiv->hash_tfm); struct scatterlist sg; struct crypto_cipher *essiv_tfm; struct crypto_completion hash_complete; int err; sg_init_one(&sg, cc->key, cc->key_size); ahash_request_set_tfm(req, essiv->hash_tfm); ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, crypt_complete, &hash_complete); init_completion(&hash_complete.restart); ahash_request_set_crypt(req, &sg, essiv->salt, cc->key_size); err = async_hash_op(req, &hash_complete, crypto_ahash_digest(req)); ahash_request_zero(req); if (err) return err; essiv_tfm = cc->iv_private; err = crypto_cipher_setkey(essiv_tfm, essiv->salt, crypto_ahash_digestsize(essiv->hash_tfm)); if (err) return err; return 0; } /* Wipe salt and reset key derived from volume key */ static int crypt_iv_essiv_wipe(struct crypt_config *cc) { struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; unsigned salt_size = crypto_ahash_digestsize(essiv->hash_tfm); struct crypto_cipher *essiv_tfm; int r, err = 0; memset(essiv->salt, 0, salt_size); essiv_tfm = cc->iv_private; r = crypto_cipher_setkey(essiv_tfm, essiv->salt, salt_size); if (r) err = r; return err; } /* Set up per cpu cipher state */ static struct crypto_cipher *setup_essiv_cpu(struct crypt_config *cc, struct dm_target *ti, u8 *salt, unsigned saltsize) { struct crypto_cipher *essiv_tfm; int err; /* Setup the essiv_tfm with the given salt */ essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC); if (IS_ERR(essiv_tfm)) { ti->error = "Error allocating crypto tfm for ESSIV"; return essiv_tfm; } if (crypto_cipher_blocksize(essiv_tfm) != crypto_skcipher_ivsize(any_tfm(cc))) { ti->error = "Block size of ESSIV cipher does " "not match IV size of block cipher"; crypto_free_cipher(essiv_tfm); return ERR_PTR(-EINVAL); } err = crypto_cipher_setkey(essiv_tfm, salt, saltsize); if (err) { ti->error = "Failed to set key for ESSIV cipher"; crypto_free_cipher(essiv_tfm); return ERR_PTR(err); } return essiv_tfm; } static void crypt_iv_essiv_dtr(struct crypt_config *cc) { struct crypto_cipher *essiv_tfm; struct iv_essiv_private *essiv = &cc->iv_gen_private.essiv; crypto_free_ahash(essiv->hash_tfm); essiv->hash_tfm = NULL; kzfree(essiv->salt); essiv->salt = NULL; essiv_tfm = cc->iv_private; if (essiv_tfm) crypto_free_cipher(essiv_tfm); cc->iv_private = NULL; } static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, const char *opts) { struct crypto_cipher *essiv_tfm = NULL; struct crypto_ahash *hash_tfm = NULL; u8 *salt = NULL; int err; if (!opts) { ti->error = "Digest algorithm missing for ESSIV mode"; return -EINVAL; } /* Allocate hash algorithm */ hash_tfm = crypto_alloc_ahash(opts, 0, CRYPTO_ALG_ASYNC); if (IS_ERR(hash_tfm)) { ti->error = "Error initializing ESSIV hash"; err = PTR_ERR(hash_tfm); goto bad; } salt = kzalloc(crypto_ahash_digestsize(hash_tfm), GFP_KERNEL); if (!salt) { ti->error = "Error kmallocing salt storage in ESSIV"; err = -ENOMEM; goto bad; } cc->iv_gen_private.essiv.salt = salt; cc->iv_gen_private.essiv.hash_tfm = hash_tfm; essiv_tfm = setup_essiv_cpu(cc, ti, salt, crypto_ahash_digestsize(hash_tfm)); if (IS_ERR(essiv_tfm)) { crypt_iv_essiv_dtr(cc); return PTR_ERR(essiv_tfm); } cc->iv_private = essiv_tfm; return 0; bad: if (hash_tfm && !IS_ERR(hash_tfm)) crypto_free_ahash(hash_tfm); kfree(salt); return err; } static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, struct dm_crypt_request *dmreq) { struct crypto_cipher *essiv_tfm = cc->iv_private; memset(iv, 0, cc->iv_size); *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector); crypto_cipher_encrypt_one(essiv_tfm, iv, iv); return 0; } static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti, const char *opts) { unsigned bs = crypto_skcipher_blocksize(any_tfm(cc)); int log = ilog2(bs); /* we need to calculate how far we must shift the sector count * to get the cipher block count, we use this shift in _gen */ if (1 << log != bs) { ti->error = "cypher blocksize is not a power of 2"; return -EINVAL; } if (log > 9) { ti->error = "cypher blocksize is > 512"; return -EINVAL; } cc->iv_gen_private.benbi.shift = 9 - log; return 0; } static void crypt_iv_benbi_dtr(struct crypt_config *cc) { } static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, struct dm_crypt_request *dmreq) { __be64 val; memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */ val = cpu_to_be64(((u64)dmreq->iv_sector << cc->iv_gen_private.benbi.shift) + 1); put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64))); return 0; } static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, struct dm_crypt_request *dmreq) { memset(iv, 0, cc->iv_size); return 0; } static void crypt_iv_lmk_dtr(struct crypt_config *cc) { struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; if (lmk->hash_tfm && !IS_ERR(lmk->hash_tfm)) crypto_free_shash(lmk->hash_tfm); lmk->hash_tfm = NULL; kzfree(lmk->seed); lmk->seed = NULL; } static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti, const char *opts) { struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; lmk->hash_tfm = crypto_alloc_shash("md5", 0, 0); if (IS_ERR(lmk->hash_tfm)) { ti->error = "Error initializing LMK hash"; return PTR_ERR(lmk->hash_tfm); } /* No seed in LMK version 2 */ if (cc->key_parts == cc->tfms_count) { lmk->seed = NULL; return 0; } lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL); if (!lmk->seed) { crypt_iv_lmk_dtr(cc); ti->error = "Error kmallocing seed storage in LMK"; return -ENOMEM; } return 0; } static int crypt_iv_lmk_init(struct crypt_config *cc) { struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; int subkey_size = cc->key_size / cc->key_parts; /* LMK seed is on the position of LMK_KEYS + 1 key */ if (lmk->seed) memcpy(lmk->seed, cc->key + (cc->tfms_count * subkey_size), crypto_shash_digestsize(lmk->hash_tfm)); return 0; } static int crypt_iv_lmk_wipe(struct crypt_config *cc) { struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; if (lmk->seed) memset(lmk->seed, 0, LMK_SEED_SIZE); return 0; } static int crypt_iv_lmk_one(struct crypt_config *cc, u8 *iv, struct dm_crypt_request *dmreq, u8 *data) { struct iv_lmk_private *lmk = &cc->iv_gen_private.lmk; SHASH_DESC_ON_STACK(desc, lmk->hash_tfm); struct md5_state md5state; __le32 buf[4]; int i, r; desc->tfm = lmk->hash_tfm; desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; r = crypto_shash_init(desc); if (r) return r; if (lmk->seed) { r = crypto_shash_update(desc, lmk->seed, LMK_SEED_SIZE); if (r) return r; } /* Sector is always 512B, block size 16, add data of blocks 1-31 */ r = crypto_shash_update(desc, data + 16, 16 * 31); if (r) return r; /* Sector is cropped to 56 bits here */ buf[0] = cpu_to_le32(dmreq->iv_sector & 0xFFFFFFFF); buf[1] = cpu_to_le32((((u64)dmreq->iv_sector >> 32) & 0x00FFFFFF) | 0x80000000); buf[2] = cpu_to_le32(4024); buf[3] = 0; r = crypto_shash_update(desc, (u8 *)buf, sizeof(buf)); if (r) return r; /* No MD5 padding here */ r = crypto_shash_export(desc, &md5state); if (r) return r; for (i = 0; i < MD5_HASH_WORDS; i++) __cpu_to_le32s(&md5state.hash[i]); memcpy(iv, &md5state.hash, cc->iv_size); return 0; } static int crypt_iv_lmk_gen(struct crypt_config *cc, u8 *iv, struct dm_crypt_request *dmreq) { u8 *src; int r = 0; if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) { src = kmap_atomic(sg_page(&dmreq->sg_in)); r = crypt_iv_lmk_one(cc, iv, dmreq, src + dmreq->sg_in.offset); kunmap_atomic(src); } else memset(iv, 0, cc->iv_size); return r; } static int crypt_iv_lmk_post(struct crypt_config *cc, u8 *iv, struct dm_crypt_request *dmreq) { u8 *dst; int r; if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) return 0; dst = kmap_atomic(sg_page(&dmreq->sg_out)); r = crypt_iv_lmk_one(cc, iv, dmreq, dst + dmreq->sg_out.offset); /* Tweak the first block of plaintext sector */ if (!r) crypto_xor(dst + dmreq->sg_out.offset, iv, cc->iv_size); kunmap_atomic(dst); return r; } static void crypt_iv_tcw_dtr(struct crypt_config *cc) { struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; kzfree(tcw->iv_seed); tcw->iv_seed = NULL; kzfree(tcw->whitening); tcw->whitening = NULL; if (tcw->crc32_tfm && !IS_ERR(tcw->crc32_tfm)) crypto_free_shash(tcw->crc32_tfm); tcw->crc32_tfm = NULL; } static int crypt_iv_tcw_ctr(struct crypt_config *cc, struct dm_target *ti, const char *opts) { struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; if (cc->key_size <= (cc->iv_size + TCW_WHITENING_SIZE)) { ti->error = "Wrong key size for TCW"; return -EINVAL; } tcw->crc32_tfm = crypto_alloc_shash("crc32", 0, 0); if (IS_ERR(tcw->crc32_tfm)) { ti->error = "Error initializing CRC32 in TCW"; return PTR_ERR(tcw->crc32_tfm); } tcw->iv_seed = kzalloc(cc->iv_size, GFP_KERNEL); tcw->whitening = kzalloc(TCW_WHITENING_SIZE, GFP_KERNEL); if (!tcw->iv_seed || !tcw->whitening) { crypt_iv_tcw_dtr(cc); ti->error = "Error allocating seed storage in TCW"; return -ENOMEM; } return 0; } static int crypt_iv_tcw_init(struct crypt_config *cc) { struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; int key_offset = cc->key_size - cc->iv_size - TCW_WHITENING_SIZE; memcpy(tcw->iv_seed, &cc->key[key_offset], cc->iv_size); memcpy(tcw->whitening, &cc->key[key_offset + cc->iv_size], TCW_WHITENING_SIZE); return 0; } static int crypt_iv_tcw_wipe(struct crypt_config *cc) { struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; memset(tcw->iv_seed, 0, cc->iv_size); memset(tcw->whitening, 0, TCW_WHITENING_SIZE); return 0; } static int crypt_iv_tcw_whitening(struct crypt_config *cc, struct dm_crypt_request *dmreq, u8 *data) { struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; __le64 sector = cpu_to_le64(dmreq->iv_sector); u8 buf[TCW_WHITENING_SIZE]; SHASH_DESC_ON_STACK(desc, tcw->crc32_tfm); int i, r; /* xor whitening with sector number */ memcpy(buf, tcw->whitening, TCW_WHITENING_SIZE); crypto_xor(buf, (u8 *)§or, 8); crypto_xor(&buf[8], (u8 *)§or, 8); /* calculate crc32 for every 32bit part and xor it */ desc->tfm = tcw->crc32_tfm; desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; for (i = 0; i < 4; i++) { r = crypto_shash_init(desc); if (r) goto out; r = crypto_shash_update(desc, &buf[i * 4], 4); if (r) goto out; r = crypto_shash_final(desc, &buf[i * 4]); if (r) goto out; } crypto_xor(&buf[0], &buf[12], 4); crypto_xor(&buf[4], &buf[8], 4); /* apply whitening (8 bytes) to whole sector */ for (i = 0; i < ((1 << SECTOR_SHIFT) / 8); i++) crypto_xor(data + i * 8, buf, 8); out: memzero_explicit(buf, sizeof(buf)); return r; } static int crypt_iv_tcw_gen(struct crypt_config *cc, u8 *iv, struct dm_crypt_request *dmreq) { struct iv_tcw_private *tcw = &cc->iv_gen_private.tcw; __le64 sector = cpu_to_le64(dmreq->iv_sector); u8 *src; int r = 0; /* Remove whitening from ciphertext */ if (bio_data_dir(dmreq->ctx->bio_in) != WRITE) { src = kmap_atomic(sg_page(&dmreq->sg_in)); r = crypt_iv_tcw_whitening(cc, dmreq, src + dmreq->sg_in.offset); kunmap_atomic(src); } /* Calculate IV */ memcpy(iv, tcw->iv_seed, cc->iv_size); crypto_xor(iv, (u8 *)§or, 8); if (cc->iv_size > 8) crypto_xor(&iv[8], (u8 *)§or, cc->iv_size - 8); return r; } static int crypt_iv_tcw_post(struct crypt_config *cc, u8 *iv, struct dm_crypt_request *dmreq) { u8 *dst; int r; if (bio_data_dir(dmreq->ctx->bio_in) != WRITE) return 0; /* Apply whitening on ciphertext */ dst = kmap_atomic(sg_page(&dmreq->sg_out)); r = crypt_iv_tcw_whitening(cc, dmreq, dst + dmreq->sg_out.offset); kunmap_atomic(dst); return r; } static struct crypt_iv_operations crypt_iv_plain_ops = { .generator = crypt_iv_plain_gen }; static struct crypt_iv_operations crypt_iv_plain64_ops = { .generator = crypt_iv_plain64_gen }; static struct crypt_iv_operations crypt_iv_essiv_ops = { .ctr = crypt_iv_essiv_ctr, .dtr = crypt_iv_essiv_dtr, .init = crypt_iv_essiv_init, .wipe = crypt_iv_essiv_wipe, .generator = crypt_iv_essiv_gen }; static struct crypt_iv_operations crypt_iv_benbi_ops = { .ctr = crypt_iv_benbi_ctr, .dtr = crypt_iv_benbi_dtr, .generator = crypt_iv_benbi_gen }; static struct crypt_iv_operations crypt_iv_null_ops = { .generator = crypt_iv_null_gen }; static struct crypt_iv_operations crypt_iv_lmk_ops = { .ctr = crypt_iv_lmk_ctr, .dtr = crypt_iv_lmk_dtr, .init = crypt_iv_lmk_init, .wipe = crypt_iv_lmk_wipe, .generator = crypt_iv_lmk_gen, .post = crypt_iv_lmk_post }; static struct crypt_iv_operations crypt_iv_tcw_ops = { .ctr = crypt_iv_tcw_ctr, .dtr = crypt_iv_tcw_dtr, .init = crypt_iv_tcw_init, .wipe = crypt_iv_tcw_wipe, .generator = crypt_iv_tcw_gen, .post = crypt_iv_tcw_post }; static void crypt_convert_init(struct crypt_config *cc, struct convert_context *ctx, struct bio *bio_out, struct bio *bio_in, sector_t sector) { ctx->bio_in = bio_in; ctx->bio_out = bio_out; if (bio_in) ctx->iter_in = bio_in->bi_iter; if (bio_out) ctx->iter_out = bio_out->bi_iter; ctx->cc_sector = sector + cc->iv_offset; init_completion(&ctx->restart); } static struct dm_crypt_request *dmreq_of_req(struct crypt_config *cc, struct skcipher_request *req) { return (struct dm_crypt_request *)((char *)req + cc->dmreq_start); } static struct skcipher_request *req_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq) { return (struct skcipher_request *)((char *)dmreq - cc->dmreq_start); } static u8 *iv_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq) { return (u8 *)ALIGN((unsigned long)(dmreq + 1), crypto_skcipher_alignmask(any_tfm(cc)) + 1); } static int crypt_convert_block(struct crypt_config *cc, struct convert_context *ctx, struct skcipher_request *req) { struct bio_vec bv_in = bio_iter_iovec(ctx->bio_in, ctx->iter_in); struct bio_vec bv_out = bio_iter_iovec(ctx->bio_out, ctx->iter_out); struct dm_crypt_request *dmreq; u8 *iv; int r; dmreq = dmreq_of_req(cc, req); iv = iv_of_dmreq(cc, dmreq); dmreq->iv_sector = ctx->cc_sector; dmreq->ctx = ctx; sg_init_table(&dmreq->sg_in, 1); sg_set_page(&dmreq->sg_in, bv_in.bv_page, 1 << SECTOR_SHIFT, bv_in.bv_offset); sg_init_table(&dmreq->sg_out, 1); sg_set_page(&dmreq->sg_out, bv_out.bv_page, 1 << SECTOR_SHIFT, bv_out.bv_offset); bio_advance_iter(ctx->bio_in, &ctx->iter_in, 1 << SECTOR_SHIFT); bio_advance_iter(ctx->bio_out, &ctx->iter_out, 1 << SECTOR_SHIFT); if (cc->iv_gen_ops) { r = cc->iv_gen_ops->generator(cc, iv, dmreq); if (r < 0) return r; } skcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out, 1 << SECTOR_SHIFT, iv); if (bio_data_dir(ctx->bio_in) == WRITE) r = crypto_skcipher_encrypt(req); else r = crypto_skcipher_decrypt(req); if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post) r = cc->iv_gen_ops->post(cc, iv, dmreq); return r; } static void kcryptd_async_done(struct crypto_async_request *async_req, int error); static void crypt_alloc_req(struct crypt_config *cc, struct convert_context *ctx) { unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1); if (!ctx->req) ctx->req = mempool_alloc(cc->req_pool, GFP_NOIO); skcipher_request_set_tfm(ctx->req, cc->tfms[key_index]); /* * Use REQ_MAY_BACKLOG so a cipher driver internally backlogs * requests if driver request queue is full. */ skcipher_request_set_callback(ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, kcryptd_async_done, dmreq_of_req(cc, ctx->req)); } static void crypt_free_req(struct crypt_config *cc, struct skcipher_request *req, struct bio *base_bio) { struct dm_crypt_io *io = dm_per_bio_data(base_bio, cc->per_bio_data_size); if ((struct skcipher_request *)(io + 1) != req) mempool_free(req, cc->req_pool); } /* * Encrypt / decrypt data from one bio to another one (can be the same one) */ static int crypt_convert(struct crypt_config *cc, struct convert_context *ctx) { int r; atomic_set(&ctx->cc_pending, 1); while (ctx->iter_in.bi_size && ctx->iter_out.bi_size) { crypt_alloc_req(cc, ctx); atomic_inc(&ctx->cc_pending); r = crypt_convert_block(cc, ctx, ctx->req); switch (r) { /* * The request was queued by a crypto driver * but the driver request queue is full, let's wait. */ case -EBUSY: wait_for_completion(&ctx->restart); reinit_completion(&ctx->restart); /* fall through */ /* * The request is queued and processed asynchronously, * completion function kcryptd_async_done() will be called. */ case -EINPROGRESS: ctx->req = NULL; ctx->cc_sector++; continue; /* * The request was already processed (synchronously). */ case 0: atomic_dec(&ctx->cc_pending); ctx->cc_sector++; cond_resched(); continue; /* There was an error while processing the request. */ default: atomic_dec(&ctx->cc_pending); return r; } } return 0; } static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone); /* * Generate a new unfragmented bio with the given size * This should never violate the device limitations (but only because * max_segment_size is being constrained to PAGE_SIZE). * * This function may be called concurrently. If we allocate from the mempool * concurrently, there is a possibility of deadlock. For example, if we have * mempool of 256 pages, two processes, each wanting 256, pages allocate from * the mempool concurrently, it may deadlock in a situation where both processes * have allocated 128 pages and the mempool is exhausted. * * In order to avoid this scenario we allocate the pages under a mutex. * * In order to not degrade performance with excessive locking, we try * non-blocking allocations without a mutex first but on failure we fallback * to blocking allocations with a mutex. */ static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size) { struct crypt_config *cc = io->cc; struct bio *clone; unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; gfp_t gfp_mask = GFP_NOWAIT | __GFP_HIGHMEM; unsigned i, len, remaining_size; struct page *page; struct bio_vec *bvec; retry: if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM)) mutex_lock(&cc->bio_alloc_lock); clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs); if (!clone) goto return_clone; clone_init(io, clone); remaining_size = size; for (i = 0; i < nr_iovecs; i++) { page = mempool_alloc(cc->page_pool, gfp_mask); if (!page) { crypt_free_buffer_pages(cc, clone); bio_put(clone); gfp_mask |= __GFP_DIRECT_RECLAIM; goto retry; } len = (remaining_size > PAGE_SIZE) ? PAGE_SIZE : remaining_size; bvec = &clone->bi_io_vec[clone->bi_vcnt++]; bvec->bv_page = page; bvec->bv_len = len; bvec->bv_offset = 0; clone->bi_iter.bi_size += len; remaining_size -= len; } return_clone: if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM)) mutex_unlock(&cc->bio_alloc_lock); return clone; } static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone) { unsigned int i; struct bio_vec *bv; bio_for_each_segment_all(bv, clone, i) { BUG_ON(!bv->bv_page); mempool_free(bv->bv_page, cc->page_pool); bv->bv_page = NULL; } } static void crypt_io_init(struct dm_crypt_io *io, struct crypt_config *cc, struct bio *bio, sector_t sector) { io->cc = cc; io->base_bio = bio; io->sector = sector; io->error = 0; io->ctx.req = NULL; atomic_set(&io->io_pending, 0); } static void crypt_inc_pending(struct dm_crypt_io *io) { atomic_inc(&io->io_pending); } /* * One of the bios was finished. Check for completion of * the whole request and correctly clean up the buffer. */ static void crypt_dec_pending(struct dm_crypt_io *io) { struct crypt_config *cc = io->cc; struct bio *base_bio = io->base_bio; int error = io->error; if (!atomic_dec_and_test(&io->io_pending)) return; if (io->ctx.req) crypt_free_req(cc, io->ctx.req, base_bio); base_bio->bi_error = error; bio_endio(base_bio); } /* * kcryptd/kcryptd_io: * * Needed because it would be very unwise to do decryption in an * interrupt context. * * kcryptd performs the actual encryption or decryption. * * kcryptd_io performs the IO submission. * * They must be separated as otherwise the final stages could be * starved by new requests which can block in the first stages due * to memory allocation. * * The work is done per CPU global for all dm-crypt instances. * They should not depend on each other and do not block. */ static void crypt_endio(struct bio *clone) { struct dm_crypt_io *io = clone->bi_private; struct crypt_config *cc = io->cc; unsigned rw = bio_data_dir(clone); int error; /* * free the processed pages */ if (rw == WRITE) crypt_free_buffer_pages(cc, clone); error = clone->bi_error; bio_put(clone); if (rw == READ && !error) { kcryptd_queue_crypt(io); return; } if (unlikely(error)) io->error = error; crypt_dec_pending(io); } static void clone_init(struct dm_crypt_io *io, struct bio *clone) { struct crypt_config *cc = io->cc; clone->bi_private = io; clone->bi_end_io = crypt_endio; clone->bi_bdev = cc->dev->bdev; bio_set_op_attrs(clone, bio_op(io->base_bio), bio_flags(io->base_bio)); } static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp) { struct crypt_config *cc = io->cc; struct bio *clone; /* * We need the original biovec array in order to decrypt * the whole bio data *afterwards* -- thanks to immutable * biovecs we don't need to worry about the block layer * modifying the biovec array; so leverage bio_clone_fast(). */ clone = bio_clone_fast(io->base_bio, gfp, cc->bs); if (!clone) return 1; crypt_inc_pending(io); clone_init(io, clone); clone->bi_iter.bi_sector = cc->start + io->sector; generic_make_request(clone); return 0; } static void kcryptd_io_read_work(struct work_struct *work) { struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); crypt_inc_pending(io); if (kcryptd_io_read(io, GFP_NOIO)) io->error = -ENOMEM; crypt_dec_pending(io); } static void kcryptd_queue_read(struct dm_crypt_io *io) { struct crypt_config *cc = io->cc; INIT_WORK(&io->work, kcryptd_io_read_work); queue_work(cc->io_queue, &io->work); } static void kcryptd_io_write(struct dm_crypt_io *io) { struct bio *clone = io->ctx.bio_out; generic_make_request(clone); } #define crypt_io_from_node(node) rb_entry((node), struct dm_crypt_io, rb_node) static int dmcrypt_write(void *data) { struct crypt_config *cc = data; struct dm_crypt_io *io; while (1) { struct rb_root write_tree; struct blk_plug plug; DECLARE_WAITQUEUE(wait, current); spin_lock_irq(&cc->write_thread_wait.lock); continue_locked: if (!RB_EMPTY_ROOT(&cc->write_tree)) goto pop_from_list; set_current_state(TASK_INTERRUPTIBLE); __add_wait_queue(&cc->write_thread_wait, &wait); spin_unlock_irq(&cc->write_thread_wait.lock); if (unlikely(kthread_should_stop())) { set_task_state(current, TASK_RUNNING); remove_wait_queue(&cc->write_thread_wait, &wait); break; } schedule(); set_task_state(current, TASK_RUNNING); spin_lock_irq(&cc->write_thread_wait.lock); __remove_wait_queue(&cc->write_thread_wait, &wait); goto continue_locked; pop_from_list: write_tree = cc->write_tree; cc->write_tree = RB_ROOT; spin_unlock_irq(&cc->write_thread_wait.lock); BUG_ON(rb_parent(write_tree.rb_node)); /* * Note: we cannot walk the tree here with rb_next because * the structures may be freed when kcryptd_io_write is called. */ blk_start_plug(&plug); do { io = crypt_io_from_node(rb_first(&write_tree)); rb_erase(&io->rb_node, &write_tree); kcryptd_io_write(io); } while (!RB_EMPTY_ROOT(&write_tree)); blk_finish_plug(&plug); } return 0; } static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async) { struct bio *clone = io->ctx.bio_out; struct crypt_config *cc = io->cc; unsigned long flags; sector_t sector; struct rb_node **rbp, *parent; if (unlikely(io->error < 0)) { crypt_free_buffer_pages(cc, clone); bio_put(clone); crypt_dec_pending(io); return; } /* crypt_convert should have filled the clone bio */ BUG_ON(io->ctx.iter_out.bi_size); clone->bi_iter.bi_sector = cc->start + io->sector; if (likely(!async) && test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) { generic_make_request(clone); return; } spin_lock_irqsave(&cc->write_thread_wait.lock, flags); rbp = &cc->write_tree.rb_node; parent = NULL; sector = io->sector; while (*rbp) { parent = *rbp; if (sector < crypt_io_from_node(parent)->sector) rbp = &(*rbp)->rb_left; else rbp = &(*rbp)->rb_right; } rb_link_node(&io->rb_node, parent, rbp); rb_insert_color(&io->rb_node, &cc->write_tree); wake_up_locked(&cc->write_thread_wait); spin_unlock_irqrestore(&cc->write_thread_wait.lock, flags); } static void kcryptd_crypt_write_convert(struct dm_crypt_io *io) { struct crypt_config *cc = io->cc; struct bio *clone; int crypt_finished; sector_t sector = io->sector; int r; /* * Prevent io from disappearing until this function completes. */ crypt_inc_pending(io); crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, sector); clone = crypt_alloc_buffer(io, io->base_bio->bi_iter.bi_size); if (unlikely(!clone)) { io->error = -EIO; goto dec; } io->ctx.bio_out = clone; io->ctx.iter_out = clone->bi_iter; sector += bio_sectors(clone); crypt_inc_pending(io); r = crypt_convert(cc, &io->ctx); if (r) io->error = -EIO; crypt_finished = atomic_dec_and_test(&io->ctx.cc_pending); /* Encryption was already finished, submit io now */ if (crypt_finished) { kcryptd_crypt_write_io_submit(io, 0); io->sector = sector; } dec: crypt_dec_pending(io); } static void kcryptd_crypt_read_done(struct dm_crypt_io *io) { crypt_dec_pending(io); } static void kcryptd_crypt_read_convert(struct dm_crypt_io *io) { struct crypt_config *cc = io->cc; int r = 0; crypt_inc_pending(io); crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio, io->sector); r = crypt_convert(cc, &io->ctx); if (r < 0) io->error = -EIO; if (atomic_dec_and_test(&io->ctx.cc_pending)) kcryptd_crypt_read_done(io); crypt_dec_pending(io); } static void kcryptd_async_done(struct crypto_async_request *async_req, int error) { struct dm_crypt_request *dmreq = async_req->data; struct convert_context *ctx = dmreq->ctx; struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx); struct crypt_config *cc = io->cc; /* * A request from crypto driver backlog is going to be processed now, * finish the completion and continue in crypt_convert(). * (Callback will be called for the second time for this request.) */ if (error == -EINPROGRESS) { complete(&ctx->restart); return; } if (!error && cc->iv_gen_ops && cc->iv_gen_ops->post) error = cc->iv_gen_ops->post(cc, iv_of_dmreq(cc, dmreq), dmreq); if (error < 0) io->error = -EIO; crypt_free_req(cc, req_of_dmreq(cc, dmreq), io->base_bio); if (!atomic_dec_and_test(&ctx->cc_pending)) return; if (bio_data_dir(io->base_bio) == READ) kcryptd_crypt_read_done(io); else kcryptd_crypt_write_io_submit(io, 1); } static void kcryptd_crypt(struct work_struct *work) { struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); if (bio_data_dir(io->base_bio) == READ) kcryptd_crypt_read_convert(io); else kcryptd_crypt_write_convert(io); } static void kcryptd_queue_crypt(struct dm_crypt_io *io) { struct crypt_config *cc = io->cc; INIT_WORK(&io->work, kcryptd_crypt); queue_work(cc->crypt_queue, &io->work); } /* * Decode key from its hex representation */ static int crypt_decode_key(u8 *key, char *hex, unsigned int size) { char buffer[3]; unsigned int i; buffer[2] = '\0'; for (i = 0; i < size; i++) { buffer[0] = *hex++; buffer[1] = *hex++; if (kstrtou8(buffer, 16, &key[i])) return -EINVAL; } if (*hex != '\0') return -EINVAL; return 0; } static void crypt_free_tfms(struct crypt_config *cc) { unsigned i; if (!cc->tfms) return; for (i = 0; i < cc->tfms_count; i++) if (cc->tfms[i] && !IS_ERR(cc->tfms[i])) { crypto_free_skcipher(cc->tfms[i]); cc->tfms[i] = NULL; } kfree(cc->tfms); cc->tfms = NULL; } static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode) { unsigned i; int err; cc->tfms = kzalloc(cc->tfms_count * sizeof(struct crypto_skcipher *), GFP_KERNEL); if (!cc->tfms) return -ENOMEM; for (i = 0; i < cc->tfms_count; i++) { cc->tfms[i] = crypto_alloc_skcipher(ciphermode, 0, 0); if (IS_ERR(cc->tfms[i])) { err = PTR_ERR(cc->tfms[i]); crypt_free_tfms(cc); return err; } } return 0; } static int crypt_setkey_allcpus(struct crypt_config *cc) { unsigned subkey_size; int err = 0, i, r; /* Ignore extra keys (which are used for IV etc) */ subkey_size = (cc->key_size - cc->key_extra_size) >> ilog2(cc->tfms_count); for (i = 0; i < cc->tfms_count; i++) { r = crypto_skcipher_setkey(cc->tfms[i], cc->key + (i * subkey_size), subkey_size); if (r) err = r; } return err; } static int crypt_set_key(struct crypt_config *cc, char *key) { int r = -EINVAL; int key_string_len = strlen(key); /* The key size may not be changed. */ if (cc->key_size != (key_string_len >> 1)) goto out; /* Hyphen (which gives a key_size of zero) means there is no key. */ if (!cc->key_size && strcmp(key, "-")) goto out; /* clear the flag since following operations may invalidate previously valid key */ clear_bit(DM_CRYPT_KEY_VALID, &cc->flags); if (cc->key_size && crypt_decode_key(cc->key, key, cc->key_size) < 0) goto out; r = crypt_setkey_allcpus(cc); if (!r) set_bit(DM_CRYPT_KEY_VALID, &cc->flags); out: /* Hex key string not needed after here, so wipe it. */ memset(key, '0', key_string_len); return r; } static int crypt_wipe_key(struct crypt_config *cc) { clear_bit(DM_CRYPT_KEY_VALID, &cc->flags); memset(&cc->key, 0, cc->key_size * sizeof(u8)); return crypt_setkey_allcpus(cc); } static void crypt_dtr(struct dm_target *ti) { struct crypt_config *cc = ti->private; ti->private = NULL; if (!cc) return; if (cc->write_thread) kthread_stop(cc->write_thread); if (cc->io_queue) destroy_workqueue(cc->io_queue); if (cc->crypt_queue) destroy_workqueue(cc->crypt_queue); crypt_free_tfms(cc); if (cc->bs) bioset_free(cc->bs); mempool_destroy(cc->page_pool); mempool_destroy(cc->req_pool); if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) cc->iv_gen_ops->dtr(cc); if (cc->dev) dm_put_device(ti, cc->dev); kzfree(cc->cipher); kzfree(cc->cipher_string); /* Must zero key material before freeing */ kzfree(cc); } static int crypt_ctr_cipher(struct dm_target *ti, char *cipher_in, char *key) { struct crypt_config *cc = ti->private; char *tmp, *cipher, *chainmode, *ivmode, *ivopts, *keycount; char *cipher_api = NULL; int ret = -EINVAL; char dummy; /* Convert to crypto api definition? */ if (strchr(cipher_in, '(')) { ti->error = "Bad cipher specification"; return -EINVAL; } cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL); if (!cc->cipher_string) goto bad_mem; /* * Legacy dm-crypt cipher specification * cipher[:keycount]-mode-iv:ivopts */ tmp = cipher_in; keycount = strsep(&tmp, "-"); cipher = strsep(&keycount, ":"); if (!keycount) cc->tfms_count = 1; else if (sscanf(keycount, "%u%c", &cc->tfms_count, &dummy) != 1 || !is_power_of_2(cc->tfms_count)) { ti->error = "Bad cipher key count specification"; return -EINVAL; } cc->key_parts = cc->tfms_count; cc->key_extra_size = 0; cc->cipher = kstrdup(cipher, GFP_KERNEL); if (!cc->cipher) goto bad_mem; chainmode = strsep(&tmp, "-"); ivopts = strsep(&tmp, "-"); ivmode = strsep(&ivopts, ":"); if (tmp) DMWARN("Ignoring unexpected additional cipher options"); /* * For compatibility with the original dm-crypt mapping format, if * only the cipher name is supplied, use cbc-plain. */ if (!chainmode || (!strcmp(chainmode, "plain") && !ivmode)) { chainmode = "cbc"; ivmode = "plain"; } if (strcmp(chainmode, "ecb") && !ivmode) { ti->error = "IV mechanism required"; return -EINVAL; } cipher_api = kmalloc(CRYPTO_MAX_ALG_NAME, GFP_KERNEL); if (!cipher_api) goto bad_mem; ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME, "%s(%s)", chainmode, cipher); if (ret < 0) { kfree(cipher_api); goto bad_mem; } /* Allocate cipher */ ret = crypt_alloc_tfms(cc, cipher_api); if (ret < 0) { ti->error = "Error allocating crypto tfm"; goto bad; } /* Initialize IV */ cc->iv_size = crypto_skcipher_ivsize(any_tfm(cc)); if (cc->iv_size) /* at least a 64 bit sector number should fit in our buffer */ cc->iv_size = max(cc->iv_size, (unsigned int)(sizeof(u64) / sizeof(u8))); else if (ivmode) { DMWARN("Selected cipher does not support IVs"); ivmode = NULL; } /* Choose ivmode, see comments at iv code. */ if (ivmode == NULL) cc->iv_gen_ops = NULL; else if (strcmp(ivmode, "plain") == 0) cc->iv_gen_ops = &crypt_iv_plain_ops; else if (strcmp(ivmode, "plain64") == 0) cc->iv_gen_ops = &crypt_iv_plain64_ops; else if (strcmp(ivmode, "essiv") == 0) cc->iv_gen_ops = &crypt_iv_essiv_ops; else if (strcmp(ivmode, "benbi") == 0) cc->iv_gen_ops = &crypt_iv_benbi_ops; else if (strcmp(ivmode, "null") == 0) cc->iv_gen_ops = &crypt_iv_null_ops; else if (strcmp(ivmode, "lmk") == 0) { cc->iv_gen_ops = &crypt_iv_lmk_ops; /* * Version 2 and 3 is recognised according * to length of provided multi-key string. * If present (version 3), last key is used as IV seed. * All keys (including IV seed) are always the same size. */ if (cc->key_size % cc->key_parts) { cc->key_parts++; cc->key_extra_size = cc->key_size / cc->key_parts; } } else if (strcmp(ivmode, "tcw") == 0) { cc->iv_gen_ops = &crypt_iv_tcw_ops; cc->key_parts += 2; /* IV + whitening */ cc->key_extra_size = cc->iv_size + TCW_WHITENING_SIZE; } else { ret = -EINVAL; ti->error = "Invalid IV mode"; goto bad; } /* Initialize and set key */ ret = crypt_set_key(cc, key); if (ret < 0) { ti->error = "Error decoding and setting key"; goto bad; } /* Allocate IV */ if (cc->iv_gen_ops && cc->iv_gen_ops->ctr) { ret = cc->iv_gen_ops->ctr(cc, ti, ivopts); if (ret < 0) { ti->error = "Error creating IV"; goto bad; } } /* Initialize IV (set keys for ESSIV etc) */ if (cc->iv_gen_ops && cc->iv_gen_ops->init) { ret = cc->iv_gen_ops->init(cc); if (ret < 0) { ti->error = "Error initialising IV"; goto bad; } } ret = 0; bad: kfree(cipher_api); return ret; bad_mem: ti->error = "Cannot allocate cipher strings"; return -ENOMEM; } /* * Construct an encryption mapping: * */ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) { struct crypt_config *cc; unsigned int key_size, opt_params; unsigned long long tmpll; int ret; size_t iv_size_padding; struct dm_arg_set as; const char *opt_string; char dummy; static struct dm_arg _args[] = { {0, 3, "Invalid number of feature args"}, }; if (argc < 5) { ti->error = "Not enough arguments"; return -EINVAL; } key_size = strlen(argv[1]) >> 1; cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL); if (!cc) { ti->error = "Cannot allocate encryption context"; return -ENOMEM; } cc->key_size = key_size; ti->private = cc; ret = crypt_ctr_cipher(ti, argv[0], argv[1]); if (ret < 0) goto bad; cc->dmreq_start = sizeof(struct skcipher_request); cc->dmreq_start += crypto_skcipher_reqsize(any_tfm(cc)); cc->dmreq_start = ALIGN(cc->dmreq_start, __alignof__(struct dm_crypt_request)); if (crypto_skcipher_alignmask(any_tfm(cc)) < CRYPTO_MINALIGN) { /* Allocate the padding exactly */ iv_size_padding = -(cc->dmreq_start + sizeof(struct dm_crypt_request)) & crypto_skcipher_alignmask(any_tfm(cc)); } else { /* * If the cipher requires greater alignment than kmalloc * alignment, we don't know the exact position of the * initialization vector. We must assume worst case. */ iv_size_padding = crypto_skcipher_alignmask(any_tfm(cc)); } ret = -ENOMEM; cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start + sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size); if (!cc->req_pool) { ti->error = "Cannot allocate crypt request mempool"; goto bad; } cc->per_bio_data_size = ti->per_io_data_size = ALIGN(sizeof(struct dm_crypt_io) + cc->dmreq_start + sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size, ARCH_KMALLOC_MINALIGN); cc->page_pool = mempool_create_page_pool(BIO_MAX_PAGES, 0); if (!cc->page_pool) { ti->error = "Cannot allocate page mempool"; goto bad; } cc->bs = bioset_create(MIN_IOS, 0); if (!cc->bs) { ti->error = "Cannot allocate crypt bioset"; goto bad; } mutex_init(&cc->bio_alloc_lock); ret = -EINVAL; if (sscanf(argv[2], "%llu%c", &tmpll, &dummy) != 1) { ti->error = "Invalid iv_offset sector"; goto bad; } cc->iv_offset = tmpll; ret = dm_get_device(ti, argv[3], dm_table_get_mode(ti->table), &cc->dev); if (ret) { ti->error = "Device lookup failed"; goto bad; } ret = -EINVAL; if (sscanf(argv[4], "%llu%c", &tmpll, &dummy) != 1) { ti->error = "Invalid device sector"; goto bad; } cc->start = tmpll; argv += 5; argc -= 5; /* Optional parameters */ if (argc) { as.argc = argc; as.argv = argv; ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error); if (ret) goto bad; ret = -EINVAL; while (opt_params--) { opt_string = dm_shift_arg(&as); if (!opt_string) { ti->error = "Not enough feature arguments"; goto bad; } if (!strcasecmp(opt_string, "allow_discards")) ti->num_discard_bios = 1; else if (!strcasecmp(opt_string, "same_cpu_crypt")) set_bit(DM_CRYPT_SAME_CPU, &cc->flags); else if (!strcasecmp(opt_string, "submit_from_crypt_cpus")) set_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags); else { ti->error = "Invalid feature arguments"; goto bad; } } } ret = -ENOMEM; cc->io_queue = alloc_workqueue("kcryptd_io", WQ_HIGHPRI | WQ_MEM_RECLAIM, 1); if (!cc->io_queue) { ti->error = "Couldn't create kcryptd io queue"; goto bad; } if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags)) cc->crypt_queue = alloc_workqueue("kcryptd", WQ_HIGHPRI | WQ_MEM_RECLAIM, 1); else cc->crypt_queue = alloc_workqueue("kcryptd", WQ_HIGHPRI | WQ_MEM_RECLAIM | WQ_UNBOUND, num_online_cpus()); if (!cc->crypt_queue) { ti->error = "Couldn't create kcryptd queue"; goto bad; } init_waitqueue_head(&cc->write_thread_wait); cc->write_tree = RB_ROOT; cc->write_thread = kthread_create(dmcrypt_write, cc, "dmcrypt_write"); if (IS_ERR(cc->write_thread)) { ret = PTR_ERR(cc->write_thread); cc->write_thread = NULL; ti->error = "Couldn't spawn write thread"; goto bad; } wake_up_process(cc->write_thread); ti->num_flush_bios = 1; ti->discard_zeroes_data_unsupported = true; return 0; bad: crypt_dtr(ti); return ret; } static int crypt_map(struct dm_target *ti, struct bio *bio) { struct dm_crypt_io *io; struct crypt_config *cc = ti->private; /* * If bio is REQ_PREFLUSH or REQ_OP_DISCARD, just bypass crypt queues. * - for REQ_PREFLUSH device-mapper core ensures that no IO is in-flight * - for REQ_OP_DISCARD caller must use flush if IO ordering matters */ if (unlikely(bio->bi_opf & REQ_PREFLUSH || bio_op(bio) == REQ_OP_DISCARD)) { bio->bi_bdev = cc->dev->bdev; if (bio_sectors(bio)) bio->bi_iter.bi_sector = cc->start + dm_target_offset(ti, bio->bi_iter.bi_sector); return DM_MAPIO_REMAPPED; } /* * Check if bio is too large, split as needed. */ if (unlikely(bio->bi_iter.bi_size > (BIO_MAX_PAGES << PAGE_SHIFT)) && bio_data_dir(bio) == WRITE) dm_accept_partial_bio(bio, ((BIO_MAX_PAGES << PAGE_SHIFT) >> SECTOR_SHIFT)); io = dm_per_bio_data(bio, cc->per_bio_data_size); crypt_io_init(io, cc, bio, dm_target_offset(ti, bio->bi_iter.bi_sector)); io->ctx.req = (struct skcipher_request *)(io + 1); if (bio_data_dir(io->base_bio) == READ) { if (kcryptd_io_read(io, GFP_NOWAIT)) kcryptd_queue_read(io); } else kcryptd_queue_crypt(io); return DM_MAPIO_SUBMITTED; } static void crypt_status(struct dm_target *ti, status_type_t type, unsigned status_flags, char *result, unsigned maxlen) { struct crypt_config *cc = ti->private; unsigned i, sz = 0; int num_feature_args = 0; switch (type) { case STATUSTYPE_INFO: result[0] = '\0'; break; case STATUSTYPE_TABLE: DMEMIT("%s ", cc->cipher_string); if (cc->key_size > 0) for (i = 0; i < cc->key_size; i++) DMEMIT("%02x", cc->key[i]); else DMEMIT("-"); DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset, cc->dev->name, (unsigned long long)cc->start); num_feature_args += !!ti->num_discard_bios; num_feature_args += test_bit(DM_CRYPT_SAME_CPU, &cc->flags); num_feature_args += test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags); if (num_feature_args) { DMEMIT(" %d", num_feature_args); if (ti->num_discard_bios) DMEMIT(" allow_discards"); if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags)) DMEMIT(" same_cpu_crypt"); if (test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) DMEMIT(" submit_from_crypt_cpus"); } break; } } static void crypt_postsuspend(struct dm_target *ti) { struct crypt_config *cc = ti->private; set_bit(DM_CRYPT_SUSPENDED, &cc->flags); } static int crypt_preresume(struct dm_target *ti) { struct crypt_config *cc = ti->private; if (!test_bit(DM_CRYPT_KEY_VALID, &cc->flags)) { DMERR("aborting resume - crypt key is not set."); return -EAGAIN; } return 0; } static void crypt_resume(struct dm_target *ti) { struct crypt_config *cc = ti->private; clear_bit(DM_CRYPT_SUSPENDED, &cc->flags); } /* Message interface * key set * key wipe */ static int crypt_message(struct dm_target *ti, unsigned argc, char **argv) { struct crypt_config *cc = ti->private; int ret = -EINVAL; if (argc < 2) goto error; if (!strcasecmp(argv[0], "key")) { if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) { DMWARN("not suspended during key manipulation."); return -EINVAL; } if (argc == 3 && !strcasecmp(argv[1], "set")) { ret = crypt_set_key(cc, argv[2]); if (ret) return ret; if (cc->iv_gen_ops && cc->iv_gen_ops->init) ret = cc->iv_gen_ops->init(cc); return ret; } if (argc == 2 && !strcasecmp(argv[1], "wipe")) { if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) { ret = cc->iv_gen_ops->wipe(cc); if (ret) return ret; } return crypt_wipe_key(cc); } } error: DMWARN("unrecognised message received."); return -EINVAL; } static int crypt_iterate_devices(struct dm_target *ti, iterate_devices_callout_fn fn, void *data) { struct crypt_config *cc = ti->private; return fn(ti, cc->dev, cc->start, ti->len, data); } static void crypt_io_hints(struct dm_target *ti, struct queue_limits *limits) { /* * Unfortunate constraint that is required to avoid the potential * for exceeding underlying device's max_segments limits -- due to * crypt_alloc_buffer() possibly allocating pages for the encryption * bio that are not as physically contiguous as the original bio. */ limits->max_segment_size = PAGE_SIZE; } static struct target_type crypt_target = { .name = "crypt", .version = {1, 14, 1}, .module = THIS_MODULE, .ctr = crypt_ctr, .dtr = crypt_dtr, .map = crypt_map, .status = crypt_status, .postsuspend = crypt_postsuspend, .preresume = crypt_preresume, .resume = crypt_resume, .message = crypt_message, .iterate_devices = crypt_iterate_devices, .io_hints = crypt_io_hints, }; static int __init dm_crypt_init(void) { int r; r = dm_register_target(&crypt_target); if (r < 0) DMERR("register failed %d", r); return r; } static void __exit dm_crypt_exit(void) { dm_unregister_target(&crypt_target); } module_init(dm_crypt_init); module_exit(dm_crypt_exit); MODULE_AUTHOR("Jana Saout "); MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption"); MODULE_LICENSE("GPL");