Add cond_resched() to prevent monopolising CPU when processing large bios. dm-crypt processes encryption of bios in sector units. If the bio request is big it can spend a long time in the encryption call. Signed-off-by: Milan Broz <mbroz@redhat.com> Tested-by: Yan Li <elliot.li.tech@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
1265 lines
29 KiB
C
1265 lines
29 KiB
C
/*
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* Copyright (C) 2003 Christophe Saout <christophe@saout.de>
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* Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
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* Copyright (C) 2006-2008 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the GPL.
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*/
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#include <linux/completion.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/mempool.h>
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#include <linux/slab.h>
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#include <linux/crypto.h>
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#include <linux/workqueue.h>
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#include <linux/backing-dev.h>
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#include <asm/atomic.h>
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#include <linux/scatterlist.h>
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#include <asm/page.h>
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#include <asm/unaligned.h>
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#include "dm.h"
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#define DM_MSG_PREFIX "crypt"
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#define MESG_STR(x) x, sizeof(x)
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/*
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* context holding the current state of a multi-part conversion
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*/
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struct convert_context {
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struct completion restart;
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struct bio *bio_in;
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struct bio *bio_out;
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unsigned int offset_in;
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unsigned int offset_out;
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unsigned int idx_in;
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unsigned int idx_out;
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sector_t sector;
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atomic_t pending;
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};
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/*
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* per bio private data
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*/
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struct dm_crypt_io {
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struct dm_target *target;
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struct bio *base_bio;
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struct work_struct work;
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struct convert_context ctx;
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atomic_t pending;
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int error;
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sector_t sector;
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};
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struct dm_crypt_request {
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struct scatterlist sg_in;
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struct scatterlist sg_out;
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};
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struct crypt_config;
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struct crypt_iv_operations {
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int (*ctr)(struct crypt_config *cc, struct dm_target *ti,
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const char *opts);
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void (*dtr)(struct crypt_config *cc);
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const char *(*status)(struct crypt_config *cc);
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int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
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};
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/*
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* Crypt: maps a linear range of a block device
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* and encrypts / decrypts at the same time.
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*/
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enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID };
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struct crypt_config {
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struct dm_dev *dev;
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sector_t start;
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/*
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* pool for per bio private data, crypto requests and
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* encryption requeusts/buffer pages
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*/
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mempool_t *io_pool;
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mempool_t *req_pool;
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mempool_t *page_pool;
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struct bio_set *bs;
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struct workqueue_struct *io_queue;
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struct workqueue_struct *crypt_queue;
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wait_queue_head_t writeq;
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/*
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* crypto related data
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*/
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struct crypt_iv_operations *iv_gen_ops;
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char *iv_mode;
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union {
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struct crypto_cipher *essiv_tfm;
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int benbi_shift;
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} iv_gen_private;
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sector_t iv_offset;
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unsigned int iv_size;
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/*
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* Layout of each crypto request:
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*
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* struct ablkcipher_request
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* context
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* padding
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* struct dm_crypt_request
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* padding
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* IV
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*
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* The padding is added so that dm_crypt_request and the IV are
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* correctly aligned.
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*/
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unsigned int dmreq_start;
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struct ablkcipher_request *req;
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char cipher[CRYPTO_MAX_ALG_NAME];
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char chainmode[CRYPTO_MAX_ALG_NAME];
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struct crypto_ablkcipher *tfm;
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unsigned long flags;
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unsigned int key_size;
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u8 key[0];
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};
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#define MIN_IOS 16
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#define MIN_POOL_PAGES 32
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#define MIN_BIO_PAGES 8
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static struct kmem_cache *_crypt_io_pool;
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static void clone_init(struct dm_crypt_io *, struct bio *);
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static void kcryptd_queue_crypt(struct dm_crypt_io *io);
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/*
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* Different IV generation algorithms:
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*
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* plain: the initial vector is the 32-bit little-endian version of the sector
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* number, padded with zeros if necessary.
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*
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* essiv: "encrypted sector|salt initial vector", the sector number is
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* encrypted with the bulk cipher using a salt as key. The salt
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* should be derived from the bulk cipher's key via hashing.
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*
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* benbi: the 64-bit "big-endian 'narrow block'-count", starting at 1
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* (needed for LRW-32-AES and possible other narrow block modes)
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*
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* null: the initial vector is always zero. Provides compatibility with
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* obsolete loop_fish2 devices. Do not use for new devices.
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*
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* plumb: unimplemented, see:
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* http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
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*/
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static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
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{
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memset(iv, 0, cc->iv_size);
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*(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
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return 0;
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}
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static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
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const char *opts)
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{
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struct crypto_cipher *essiv_tfm;
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struct crypto_hash *hash_tfm;
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struct hash_desc desc;
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struct scatterlist sg;
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unsigned int saltsize;
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u8 *salt;
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int err;
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if (opts == NULL) {
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ti->error = "Digest algorithm missing for ESSIV mode";
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return -EINVAL;
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}
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/* Hash the cipher key with the given hash algorithm */
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hash_tfm = crypto_alloc_hash(opts, 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(hash_tfm)) {
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ti->error = "Error initializing ESSIV hash";
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return PTR_ERR(hash_tfm);
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}
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saltsize = crypto_hash_digestsize(hash_tfm);
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salt = kmalloc(saltsize, GFP_KERNEL);
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if (salt == NULL) {
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ti->error = "Error kmallocing salt storage in ESSIV";
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crypto_free_hash(hash_tfm);
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return -ENOMEM;
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}
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sg_init_one(&sg, cc->key, cc->key_size);
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desc.tfm = hash_tfm;
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desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
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err = crypto_hash_digest(&desc, &sg, cc->key_size, salt);
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crypto_free_hash(hash_tfm);
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if (err) {
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ti->error = "Error calculating hash in ESSIV";
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kfree(salt);
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return err;
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}
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/* Setup the essiv_tfm with the given salt */
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essiv_tfm = crypto_alloc_cipher(cc->cipher, 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(essiv_tfm)) {
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ti->error = "Error allocating crypto tfm for ESSIV";
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kfree(salt);
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return PTR_ERR(essiv_tfm);
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}
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if (crypto_cipher_blocksize(essiv_tfm) !=
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crypto_ablkcipher_ivsize(cc->tfm)) {
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ti->error = "Block size of ESSIV cipher does "
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"not match IV size of block cipher";
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crypto_free_cipher(essiv_tfm);
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kfree(salt);
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return -EINVAL;
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}
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err = crypto_cipher_setkey(essiv_tfm, salt, saltsize);
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if (err) {
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ti->error = "Failed to set key for ESSIV cipher";
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crypto_free_cipher(essiv_tfm);
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kfree(salt);
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return err;
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}
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kfree(salt);
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cc->iv_gen_private.essiv_tfm = essiv_tfm;
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return 0;
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}
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static void crypt_iv_essiv_dtr(struct crypt_config *cc)
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{
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crypto_free_cipher(cc->iv_gen_private.essiv_tfm);
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cc->iv_gen_private.essiv_tfm = NULL;
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}
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static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
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{
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memset(iv, 0, cc->iv_size);
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*(u64 *)iv = cpu_to_le64(sector);
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crypto_cipher_encrypt_one(cc->iv_gen_private.essiv_tfm, iv, iv);
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return 0;
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}
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static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,
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const char *opts)
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{
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unsigned bs = crypto_ablkcipher_blocksize(cc->tfm);
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int log = ilog2(bs);
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/* we need to calculate how far we must shift the sector count
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* to get the cipher block count, we use this shift in _gen */
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if (1 << log != bs) {
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ti->error = "cypher blocksize is not a power of 2";
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return -EINVAL;
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}
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if (log > 9) {
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ti->error = "cypher blocksize is > 512";
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return -EINVAL;
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}
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cc->iv_gen_private.benbi_shift = 9 - log;
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return 0;
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}
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static void crypt_iv_benbi_dtr(struct crypt_config *cc)
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{
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}
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static int crypt_iv_benbi_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
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{
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__be64 val;
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memset(iv, 0, cc->iv_size - sizeof(u64)); /* rest is cleared below */
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val = cpu_to_be64(((u64)sector << cc->iv_gen_private.benbi_shift) + 1);
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put_unaligned(val, (__be64 *)(iv + cc->iv_size - sizeof(u64)));
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return 0;
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}
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static int crypt_iv_null_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
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{
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memset(iv, 0, cc->iv_size);
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return 0;
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}
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static struct crypt_iv_operations crypt_iv_plain_ops = {
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.generator = crypt_iv_plain_gen
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};
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static struct crypt_iv_operations crypt_iv_essiv_ops = {
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.ctr = crypt_iv_essiv_ctr,
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.dtr = crypt_iv_essiv_dtr,
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.generator = crypt_iv_essiv_gen
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};
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static struct crypt_iv_operations crypt_iv_benbi_ops = {
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.ctr = crypt_iv_benbi_ctr,
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.dtr = crypt_iv_benbi_dtr,
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.generator = crypt_iv_benbi_gen
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};
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static struct crypt_iv_operations crypt_iv_null_ops = {
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.generator = crypt_iv_null_gen
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};
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static void crypt_convert_init(struct crypt_config *cc,
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struct convert_context *ctx,
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struct bio *bio_out, struct bio *bio_in,
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sector_t sector)
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{
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ctx->bio_in = bio_in;
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ctx->bio_out = bio_out;
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ctx->offset_in = 0;
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ctx->offset_out = 0;
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ctx->idx_in = bio_in ? bio_in->bi_idx : 0;
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ctx->idx_out = bio_out ? bio_out->bi_idx : 0;
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ctx->sector = sector + cc->iv_offset;
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init_completion(&ctx->restart);
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atomic_set(&ctx->pending, 1);
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}
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static int crypt_convert_block(struct crypt_config *cc,
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struct convert_context *ctx,
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struct ablkcipher_request *req)
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{
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struct bio_vec *bv_in = bio_iovec_idx(ctx->bio_in, ctx->idx_in);
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struct bio_vec *bv_out = bio_iovec_idx(ctx->bio_out, ctx->idx_out);
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struct dm_crypt_request *dmreq;
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u8 *iv;
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int r = 0;
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dmreq = (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
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iv = (u8 *)ALIGN((unsigned long)(dmreq + 1),
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crypto_ablkcipher_alignmask(cc->tfm) + 1);
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sg_init_table(&dmreq->sg_in, 1);
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sg_set_page(&dmreq->sg_in, bv_in->bv_page, 1 << SECTOR_SHIFT,
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bv_in->bv_offset + ctx->offset_in);
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sg_init_table(&dmreq->sg_out, 1);
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sg_set_page(&dmreq->sg_out, bv_out->bv_page, 1 << SECTOR_SHIFT,
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bv_out->bv_offset + ctx->offset_out);
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ctx->offset_in += 1 << SECTOR_SHIFT;
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if (ctx->offset_in >= bv_in->bv_len) {
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ctx->offset_in = 0;
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ctx->idx_in++;
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}
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ctx->offset_out += 1 << SECTOR_SHIFT;
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if (ctx->offset_out >= bv_out->bv_len) {
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ctx->offset_out = 0;
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ctx->idx_out++;
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}
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if (cc->iv_gen_ops) {
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r = cc->iv_gen_ops->generator(cc, iv, ctx->sector);
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if (r < 0)
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return r;
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}
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ablkcipher_request_set_crypt(req, &dmreq->sg_in, &dmreq->sg_out,
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1 << SECTOR_SHIFT, iv);
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if (bio_data_dir(ctx->bio_in) == WRITE)
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r = crypto_ablkcipher_encrypt(req);
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else
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r = crypto_ablkcipher_decrypt(req);
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return r;
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}
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static void kcryptd_async_done(struct crypto_async_request *async_req,
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int error);
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static void crypt_alloc_req(struct crypt_config *cc,
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struct convert_context *ctx)
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{
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if (!cc->req)
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cc->req = mempool_alloc(cc->req_pool, GFP_NOIO);
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ablkcipher_request_set_tfm(cc->req, cc->tfm);
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ablkcipher_request_set_callback(cc->req, CRYPTO_TFM_REQ_MAY_BACKLOG |
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CRYPTO_TFM_REQ_MAY_SLEEP,
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kcryptd_async_done, ctx);
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}
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/*
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* Encrypt / decrypt data from one bio to another one (can be the same one)
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*/
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static int crypt_convert(struct crypt_config *cc,
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struct convert_context *ctx)
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{
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int r;
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while(ctx->idx_in < ctx->bio_in->bi_vcnt &&
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ctx->idx_out < ctx->bio_out->bi_vcnt) {
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crypt_alloc_req(cc, ctx);
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atomic_inc(&ctx->pending);
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r = crypt_convert_block(cc, ctx, cc->req);
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switch (r) {
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/* async */
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case -EBUSY:
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wait_for_completion(&ctx->restart);
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INIT_COMPLETION(ctx->restart);
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/* fall through*/
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case -EINPROGRESS:
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cc->req = NULL;
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ctx->sector++;
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continue;
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/* sync */
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case 0:
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atomic_dec(&ctx->pending);
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ctx->sector++;
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cond_resched();
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continue;
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/* error */
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default:
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atomic_dec(&ctx->pending);
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return r;
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}
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}
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return 0;
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}
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static void dm_crypt_bio_destructor(struct bio *bio)
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{
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struct dm_crypt_io *io = bio->bi_private;
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struct crypt_config *cc = io->target->private;
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bio_free(bio, cc->bs);
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}
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/*
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* Generate a new unfragmented bio with the given size
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* This should never violate the device limitations
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* May return a smaller bio when running out of pages
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*/
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static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size)
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{
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struct crypt_config *cc = io->target->private;
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struct bio *clone;
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unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
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gfp_t gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
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unsigned i, len;
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struct page *page;
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clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, cc->bs);
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if (!clone)
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return NULL;
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clone_init(io, clone);
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for (i = 0; i < nr_iovecs; i++) {
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page = mempool_alloc(cc->page_pool, gfp_mask);
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if (!page)
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break;
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/*
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* if additional pages cannot be allocated without waiting,
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* return a partially allocated bio, the caller will then try
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* to allocate additional bios while submitting this partial bio
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*/
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if (i == (MIN_BIO_PAGES - 1))
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gfp_mask = (gfp_mask | __GFP_NOWARN) & ~__GFP_WAIT;
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len = (size > PAGE_SIZE) ? PAGE_SIZE : size;
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if (!bio_add_page(clone, page, len, 0)) {
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mempool_free(page, cc->page_pool);
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break;
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}
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size -= len;
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}
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if (!clone->bi_size) {
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bio_put(clone);
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return NULL;
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}
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return clone;
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}
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static void crypt_free_buffer_pages(struct crypt_config *cc, struct bio *clone)
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{
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unsigned int i;
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struct bio_vec *bv;
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for (i = 0; i < clone->bi_vcnt; i++) {
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bv = bio_iovec_idx(clone, i);
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BUG_ON(!bv->bv_page);
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mempool_free(bv->bv_page, cc->page_pool);
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bv->bv_page = NULL;
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}
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}
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|
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/*
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* One of the bios was finished. Check for completion of
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* the whole request and correctly clean up the buffer.
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*/
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static void crypt_dec_pending(struct dm_crypt_io *io)
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|
{
|
|
struct crypt_config *cc = io->target->private;
|
|
|
|
if (!atomic_dec_and_test(&io->pending))
|
|
return;
|
|
|
|
bio_endio(io->base_bio, io->error);
|
|
mempool_free(io, cc->io_pool);
|
|
}
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
static void crypt_endio(struct bio *clone, int error)
|
|
{
|
|
struct dm_crypt_io *io = clone->bi_private;
|
|
struct crypt_config *cc = io->target->private;
|
|
unsigned rw = bio_data_dir(clone);
|
|
|
|
if (unlikely(!bio_flagged(clone, BIO_UPTODATE) && !error))
|
|
error = -EIO;
|
|
|
|
/*
|
|
* free the processed pages
|
|
*/
|
|
if (rw == WRITE)
|
|
crypt_free_buffer_pages(cc, clone);
|
|
|
|
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->target->private;
|
|
|
|
clone->bi_private = io;
|
|
clone->bi_end_io = crypt_endio;
|
|
clone->bi_bdev = cc->dev->bdev;
|
|
clone->bi_rw = io->base_bio->bi_rw;
|
|
clone->bi_destructor = dm_crypt_bio_destructor;
|
|
}
|
|
|
|
static void kcryptd_io_read(struct dm_crypt_io *io)
|
|
{
|
|
struct crypt_config *cc = io->target->private;
|
|
struct bio *base_bio = io->base_bio;
|
|
struct bio *clone;
|
|
|
|
atomic_inc(&io->pending);
|
|
|
|
/*
|
|
* The block layer might modify the bvec array, so always
|
|
* copy the required bvecs because we need the original
|
|
* one in order to decrypt the whole bio data *afterwards*.
|
|
*/
|
|
clone = bio_alloc_bioset(GFP_NOIO, bio_segments(base_bio), cc->bs);
|
|
if (unlikely(!clone)) {
|
|
io->error = -ENOMEM;
|
|
crypt_dec_pending(io);
|
|
return;
|
|
}
|
|
|
|
clone_init(io, clone);
|
|
clone->bi_idx = 0;
|
|
clone->bi_vcnt = bio_segments(base_bio);
|
|
clone->bi_size = base_bio->bi_size;
|
|
clone->bi_sector = cc->start + io->sector;
|
|
memcpy(clone->bi_io_vec, bio_iovec(base_bio),
|
|
sizeof(struct bio_vec) * clone->bi_vcnt);
|
|
|
|
generic_make_request(clone);
|
|
}
|
|
|
|
static void kcryptd_io_write(struct dm_crypt_io *io)
|
|
{
|
|
struct bio *clone = io->ctx.bio_out;
|
|
struct crypt_config *cc = io->target->private;
|
|
|
|
generic_make_request(clone);
|
|
wake_up(&cc->writeq);
|
|
}
|
|
|
|
static void kcryptd_io(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_io_read(io);
|
|
else
|
|
kcryptd_io_write(io);
|
|
}
|
|
|
|
static void kcryptd_queue_io(struct dm_crypt_io *io)
|
|
{
|
|
struct crypt_config *cc = io->target->private;
|
|
|
|
INIT_WORK(&io->work, kcryptd_io);
|
|
queue_work(cc->io_queue, &io->work);
|
|
}
|
|
|
|
static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io,
|
|
int error, int async)
|
|
{
|
|
struct bio *clone = io->ctx.bio_out;
|
|
struct crypt_config *cc = io->target->private;
|
|
|
|
if (unlikely(error < 0)) {
|
|
crypt_free_buffer_pages(cc, clone);
|
|
bio_put(clone);
|
|
io->error = -EIO;
|
|
return;
|
|
}
|
|
|
|
/* crypt_convert should have filled the clone bio */
|
|
BUG_ON(io->ctx.idx_out < clone->bi_vcnt);
|
|
|
|
clone->bi_sector = cc->start + io->sector;
|
|
io->sector += bio_sectors(clone);
|
|
|
|
if (async)
|
|
kcryptd_queue_io(io);
|
|
else {
|
|
atomic_inc(&io->pending);
|
|
generic_make_request(clone);
|
|
}
|
|
}
|
|
|
|
static void kcryptd_crypt_write_convert_loop(struct dm_crypt_io *io)
|
|
{
|
|
struct crypt_config *cc = io->target->private;
|
|
struct bio *clone;
|
|
unsigned remaining = io->base_bio->bi_size;
|
|
int r;
|
|
|
|
/*
|
|
* The allocated buffers can be smaller than the whole bio,
|
|
* so repeat the whole process until all the data can be handled.
|
|
*/
|
|
while (remaining) {
|
|
clone = crypt_alloc_buffer(io, remaining);
|
|
if (unlikely(!clone)) {
|
|
io->error = -ENOMEM;
|
|
return;
|
|
}
|
|
|
|
io->ctx.bio_out = clone;
|
|
io->ctx.idx_out = 0;
|
|
|
|
remaining -= clone->bi_size;
|
|
|
|
r = crypt_convert(cc, &io->ctx);
|
|
|
|
if (atomic_dec_and_test(&io->ctx.pending)) {
|
|
/* processed, no running async crypto */
|
|
kcryptd_crypt_write_io_submit(io, r, 0);
|
|
if (unlikely(r < 0))
|
|
return;
|
|
} else
|
|
atomic_inc(&io->pending);
|
|
|
|
/* out of memory -> run queues */
|
|
if (unlikely(remaining)) {
|
|
/* wait for async crypto then reinitialize pending */
|
|
wait_event(cc->writeq, !atomic_read(&io->ctx.pending));
|
|
atomic_set(&io->ctx.pending, 1);
|
|
congestion_wait(WRITE, HZ/100);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void kcryptd_crypt_write_convert(struct dm_crypt_io *io)
|
|
{
|
|
struct crypt_config *cc = io->target->private;
|
|
|
|
/*
|
|
* Prevent io from disappearing until this function completes.
|
|
*/
|
|
atomic_inc(&io->pending);
|
|
|
|
crypt_convert_init(cc, &io->ctx, NULL, io->base_bio, io->sector);
|
|
kcryptd_crypt_write_convert_loop(io);
|
|
|
|
crypt_dec_pending(io);
|
|
}
|
|
|
|
static void kcryptd_crypt_read_done(struct dm_crypt_io *io, int error)
|
|
{
|
|
if (unlikely(error < 0))
|
|
io->error = -EIO;
|
|
|
|
crypt_dec_pending(io);
|
|
}
|
|
|
|
static void kcryptd_crypt_read_convert(struct dm_crypt_io *io)
|
|
{
|
|
struct crypt_config *cc = io->target->private;
|
|
int r = 0;
|
|
|
|
atomic_inc(&io->pending);
|
|
|
|
crypt_convert_init(cc, &io->ctx, io->base_bio, io->base_bio,
|
|
io->sector);
|
|
|
|
r = crypt_convert(cc, &io->ctx);
|
|
|
|
if (atomic_dec_and_test(&io->ctx.pending))
|
|
kcryptd_crypt_read_done(io, r);
|
|
|
|
crypt_dec_pending(io);
|
|
}
|
|
|
|
static void kcryptd_async_done(struct crypto_async_request *async_req,
|
|
int error)
|
|
{
|
|
struct convert_context *ctx = async_req->data;
|
|
struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
|
|
struct crypt_config *cc = io->target->private;
|
|
|
|
if (error == -EINPROGRESS) {
|
|
complete(&ctx->restart);
|
|
return;
|
|
}
|
|
|
|
mempool_free(ablkcipher_request_cast(async_req), cc->req_pool);
|
|
|
|
if (!atomic_dec_and_test(&ctx->pending))
|
|
return;
|
|
|
|
if (bio_data_dir(io->base_bio) == READ)
|
|
kcryptd_crypt_read_done(io, error);
|
|
else
|
|
kcryptd_crypt_write_io_submit(io, error, 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->target->private;
|
|
|
|
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];
|
|
char *endp;
|
|
unsigned int i;
|
|
|
|
buffer[2] = '\0';
|
|
|
|
for (i = 0; i < size; i++) {
|
|
buffer[0] = *hex++;
|
|
buffer[1] = *hex++;
|
|
|
|
key[i] = (u8)simple_strtoul(buffer, &endp, 16);
|
|
|
|
if (endp != &buffer[2])
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (*hex != '\0')
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Encode key into its hex representation
|
|
*/
|
|
static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < size; i++) {
|
|
sprintf(hex, "%02x", *key);
|
|
hex += 2;
|
|
key++;
|
|
}
|
|
}
|
|
|
|
static int crypt_set_key(struct crypt_config *cc, char *key)
|
|
{
|
|
unsigned key_size = strlen(key) >> 1;
|
|
|
|
if (cc->key_size && cc->key_size != key_size)
|
|
return -EINVAL;
|
|
|
|
cc->key_size = key_size; /* initial settings */
|
|
|
|
if ((!key_size && strcmp(key, "-")) ||
|
|
(key_size && crypt_decode_key(cc->key, key, key_size) < 0))
|
|
return -EINVAL;
|
|
|
|
set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
|
|
|
|
return 0;
|
|
}
|
|
|
|
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 0;
|
|
}
|
|
|
|
/*
|
|
* Construct an encryption mapping:
|
|
* <cipher> <key> <iv_offset> <dev_path> <start>
|
|
*/
|
|
static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
|
|
{
|
|
struct crypt_config *cc;
|
|
struct crypto_ablkcipher *tfm;
|
|
char *tmp;
|
|
char *cipher;
|
|
char *chainmode;
|
|
char *ivmode;
|
|
char *ivopts;
|
|
unsigned int key_size;
|
|
unsigned long long tmpll;
|
|
|
|
if (argc != 5) {
|
|
ti->error = "Not enough arguments";
|
|
return -EINVAL;
|
|
}
|
|
|
|
tmp = argv[0];
|
|
cipher = strsep(&tmp, "-");
|
|
chainmode = strsep(&tmp, "-");
|
|
ivopts = strsep(&tmp, "-");
|
|
ivmode = strsep(&ivopts, ":");
|
|
|
|
if (tmp)
|
|
DMWARN("Unexpected additional cipher options");
|
|
|
|
key_size = strlen(argv[1]) >> 1;
|
|
|
|
cc = kzalloc(sizeof(*cc) + key_size * sizeof(u8), GFP_KERNEL);
|
|
if (cc == NULL) {
|
|
ti->error =
|
|
"Cannot allocate transparent encryption context";
|
|
return -ENOMEM;
|
|
}
|
|
|
|
if (crypt_set_key(cc, argv[1])) {
|
|
ti->error = "Error decoding key";
|
|
goto bad_cipher;
|
|
}
|
|
|
|
/* Compatiblity mode for old dm-crypt cipher strings */
|
|
if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
|
|
chainmode = "cbc";
|
|
ivmode = "plain";
|
|
}
|
|
|
|
if (strcmp(chainmode, "ecb") && !ivmode) {
|
|
ti->error = "This chaining mode requires an IV mechanism";
|
|
goto bad_cipher;
|
|
}
|
|
|
|
if (snprintf(cc->cipher, CRYPTO_MAX_ALG_NAME, "%s(%s)",
|
|
chainmode, cipher) >= CRYPTO_MAX_ALG_NAME) {
|
|
ti->error = "Chain mode + cipher name is too long";
|
|
goto bad_cipher;
|
|
}
|
|
|
|
tfm = crypto_alloc_ablkcipher(cc->cipher, 0, 0);
|
|
if (IS_ERR(tfm)) {
|
|
ti->error = "Error allocating crypto tfm";
|
|
goto bad_cipher;
|
|
}
|
|
|
|
strcpy(cc->cipher, cipher);
|
|
strcpy(cc->chainmode, chainmode);
|
|
cc->tfm = tfm;
|
|
|
|
/*
|
|
* Choose ivmode. Valid modes: "plain", "essiv:<esshash>", "benbi".
|
|
* 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, "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 {
|
|
ti->error = "Invalid IV mode";
|
|
goto bad_ivmode;
|
|
}
|
|
|
|
if (cc->iv_gen_ops && cc->iv_gen_ops->ctr &&
|
|
cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
|
|
goto bad_ivmode;
|
|
|
|
cc->iv_size = crypto_ablkcipher_ivsize(tfm);
|
|
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 (cc->iv_gen_ops) {
|
|
DMWARN("Selected cipher does not support IVs");
|
|
if (cc->iv_gen_ops->dtr)
|
|
cc->iv_gen_ops->dtr(cc);
|
|
cc->iv_gen_ops = NULL;
|
|
}
|
|
}
|
|
|
|
cc->io_pool = mempool_create_slab_pool(MIN_IOS, _crypt_io_pool);
|
|
if (!cc->io_pool) {
|
|
ti->error = "Cannot allocate crypt io mempool";
|
|
goto bad_slab_pool;
|
|
}
|
|
|
|
cc->dmreq_start = sizeof(struct ablkcipher_request);
|
|
cc->dmreq_start += crypto_ablkcipher_reqsize(tfm);
|
|
cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
|
|
cc->dmreq_start += crypto_ablkcipher_alignmask(tfm) &
|
|
~(crypto_tfm_ctx_alignment() - 1);
|
|
|
|
cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
|
|
sizeof(struct dm_crypt_request) + cc->iv_size);
|
|
if (!cc->req_pool) {
|
|
ti->error = "Cannot allocate crypt request mempool";
|
|
goto bad_req_pool;
|
|
}
|
|
cc->req = NULL;
|
|
|
|
cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
|
|
if (!cc->page_pool) {
|
|
ti->error = "Cannot allocate page mempool";
|
|
goto bad_page_pool;
|
|
}
|
|
|
|
cc->bs = bioset_create(MIN_IOS, MIN_IOS);
|
|
if (!cc->bs) {
|
|
ti->error = "Cannot allocate crypt bioset";
|
|
goto bad_bs;
|
|
}
|
|
|
|
if (crypto_ablkcipher_setkey(tfm, cc->key, key_size) < 0) {
|
|
ti->error = "Error setting key";
|
|
goto bad_device;
|
|
}
|
|
|
|
if (sscanf(argv[2], "%llu", &tmpll) != 1) {
|
|
ti->error = "Invalid iv_offset sector";
|
|
goto bad_device;
|
|
}
|
|
cc->iv_offset = tmpll;
|
|
|
|
if (sscanf(argv[4], "%llu", &tmpll) != 1) {
|
|
ti->error = "Invalid device sector";
|
|
goto bad_device;
|
|
}
|
|
cc->start = tmpll;
|
|
|
|
if (dm_get_device(ti, argv[3], cc->start, ti->len,
|
|
dm_table_get_mode(ti->table), &cc->dev)) {
|
|
ti->error = "Device lookup failed";
|
|
goto bad_device;
|
|
}
|
|
|
|
if (ivmode && cc->iv_gen_ops) {
|
|
if (ivopts)
|
|
*(ivopts - 1) = ':';
|
|
cc->iv_mode = kmalloc(strlen(ivmode) + 1, GFP_KERNEL);
|
|
if (!cc->iv_mode) {
|
|
ti->error = "Error kmallocing iv_mode string";
|
|
goto bad_ivmode_string;
|
|
}
|
|
strcpy(cc->iv_mode, ivmode);
|
|
} else
|
|
cc->iv_mode = NULL;
|
|
|
|
cc->io_queue = create_singlethread_workqueue("kcryptd_io");
|
|
if (!cc->io_queue) {
|
|
ti->error = "Couldn't create kcryptd io queue";
|
|
goto bad_io_queue;
|
|
}
|
|
|
|
cc->crypt_queue = create_singlethread_workqueue("kcryptd");
|
|
if (!cc->crypt_queue) {
|
|
ti->error = "Couldn't create kcryptd queue";
|
|
goto bad_crypt_queue;
|
|
}
|
|
|
|
init_waitqueue_head(&cc->writeq);
|
|
ti->private = cc;
|
|
return 0;
|
|
|
|
bad_crypt_queue:
|
|
destroy_workqueue(cc->io_queue);
|
|
bad_io_queue:
|
|
kfree(cc->iv_mode);
|
|
bad_ivmode_string:
|
|
dm_put_device(ti, cc->dev);
|
|
bad_device:
|
|
bioset_free(cc->bs);
|
|
bad_bs:
|
|
mempool_destroy(cc->page_pool);
|
|
bad_page_pool:
|
|
mempool_destroy(cc->req_pool);
|
|
bad_req_pool:
|
|
mempool_destroy(cc->io_pool);
|
|
bad_slab_pool:
|
|
if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
|
|
cc->iv_gen_ops->dtr(cc);
|
|
bad_ivmode:
|
|
crypto_free_ablkcipher(tfm);
|
|
bad_cipher:
|
|
/* Must zero key material before freeing */
|
|
memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
|
|
kfree(cc);
|
|
return -EINVAL;
|
|
}
|
|
|
|
static void crypt_dtr(struct dm_target *ti)
|
|
{
|
|
struct crypt_config *cc = (struct crypt_config *) ti->private;
|
|
|
|
destroy_workqueue(cc->io_queue);
|
|
destroy_workqueue(cc->crypt_queue);
|
|
|
|
if (cc->req)
|
|
mempool_free(cc->req, cc->req_pool);
|
|
|
|
bioset_free(cc->bs);
|
|
mempool_destroy(cc->page_pool);
|
|
mempool_destroy(cc->req_pool);
|
|
mempool_destroy(cc->io_pool);
|
|
|
|
kfree(cc->iv_mode);
|
|
if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
|
|
cc->iv_gen_ops->dtr(cc);
|
|
crypto_free_ablkcipher(cc->tfm);
|
|
dm_put_device(ti, cc->dev);
|
|
|
|
/* Must zero key material before freeing */
|
|
memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
|
|
kfree(cc);
|
|
}
|
|
|
|
static int crypt_map(struct dm_target *ti, struct bio *bio,
|
|
union map_info *map_context)
|
|
{
|
|
struct crypt_config *cc = ti->private;
|
|
struct dm_crypt_io *io;
|
|
|
|
io = mempool_alloc(cc->io_pool, GFP_NOIO);
|
|
io->target = ti;
|
|
io->base_bio = bio;
|
|
io->sector = bio->bi_sector - ti->begin;
|
|
io->error = 0;
|
|
atomic_set(&io->pending, 0);
|
|
|
|
if (bio_data_dir(io->base_bio) == READ)
|
|
kcryptd_queue_io(io);
|
|
else
|
|
kcryptd_queue_crypt(io);
|
|
|
|
return DM_MAPIO_SUBMITTED;
|
|
}
|
|
|
|
static int crypt_status(struct dm_target *ti, status_type_t type,
|
|
char *result, unsigned int maxlen)
|
|
{
|
|
struct crypt_config *cc = (struct crypt_config *) ti->private;
|
|
unsigned int sz = 0;
|
|
|
|
switch (type) {
|
|
case STATUSTYPE_INFO:
|
|
result[0] = '\0';
|
|
break;
|
|
|
|
case STATUSTYPE_TABLE:
|
|
if (cc->iv_mode)
|
|
DMEMIT("%s-%s-%s ", cc->cipher, cc->chainmode,
|
|
cc->iv_mode);
|
|
else
|
|
DMEMIT("%s-%s ", cc->cipher, cc->chainmode);
|
|
|
|
if (cc->key_size > 0) {
|
|
if ((maxlen - sz) < ((cc->key_size << 1) + 1))
|
|
return -ENOMEM;
|
|
|
|
crypt_encode_key(result + sz, cc->key, cc->key_size);
|
|
sz += cc->key_size << 1;
|
|
} else {
|
|
if (sz >= maxlen)
|
|
return -ENOMEM;
|
|
result[sz++] = '-';
|
|
}
|
|
|
|
DMEMIT(" %llu %s %llu", (unsigned long long)cc->iv_offset,
|
|
cc->dev->name, (unsigned long long)cc->start);
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
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>
|
|
* key wipe
|
|
*/
|
|
static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
|
|
{
|
|
struct crypt_config *cc = ti->private;
|
|
|
|
if (argc < 2)
|
|
goto error;
|
|
|
|
if (!strnicmp(argv[0], MESG_STR("key"))) {
|
|
if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
|
|
DMWARN("not suspended during key manipulation.");
|
|
return -EINVAL;
|
|
}
|
|
if (argc == 3 && !strnicmp(argv[1], MESG_STR("set")))
|
|
return crypt_set_key(cc, argv[2]);
|
|
if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe")))
|
|
return crypt_wipe_key(cc);
|
|
}
|
|
|
|
error:
|
|
DMWARN("unrecognised message received.");
|
|
return -EINVAL;
|
|
}
|
|
|
|
static struct target_type crypt_target = {
|
|
.name = "crypt",
|
|
.version= {1, 5, 0},
|
|
.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,
|
|
};
|
|
|
|
static int __init dm_crypt_init(void)
|
|
{
|
|
int r;
|
|
|
|
_crypt_io_pool = KMEM_CACHE(dm_crypt_io, 0);
|
|
if (!_crypt_io_pool)
|
|
return -ENOMEM;
|
|
|
|
r = dm_register_target(&crypt_target);
|
|
if (r < 0) {
|
|
DMERR("register failed %d", r);
|
|
kmem_cache_destroy(_crypt_io_pool);
|
|
}
|
|
|
|
return r;
|
|
}
|
|
|
|
static void __exit dm_crypt_exit(void)
|
|
{
|
|
int r = dm_unregister_target(&crypt_target);
|
|
|
|
if (r < 0)
|
|
DMERR("unregister failed %d", r);
|
|
|
|
kmem_cache_destroy(_crypt_io_pool);
|
|
}
|
|
|
|
module_init(dm_crypt_init);
|
|
module_exit(dm_crypt_exit);
|
|
|
|
MODULE_AUTHOR("Christophe Saout <christophe@saout.de>");
|
|
MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
|
|
MODULE_LICENSE("GPL");
|