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linux/drivers/md/dm-crypt.c
Mikulas Patocka 5059353df8 dm crypt: limit the number of allocated pages 
dm-crypt consumes an excessive amount memory when the user attempts to
zero a dm-crypt device with "blkdiscard -z". The command "blkdiscard -z"
calls the BLKZEROOUT ioctl, it goes to the function __blkdev_issue_zeroout,
__blkdev_issue_zeroout sends a large amount of write bios that contain
the zero page as their payload.

For each incoming page, dm-crypt allocates another page that holds the
encrypted data, so when processing "blkdiscard -z", dm-crypt tries to
allocate the amount of memory that is equal to the size of the device.
This can trigger OOM killer or cause system crash.

Fix this by limiting the amount of memory that dm-crypt allocates to 2%
of total system memory. This limit is system-wide and is divided by the
number of active dm-crypt devices and each device receives an equal
share.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2018-04-03 15:04:11 -04:00

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/*
* Copyright (C) 2003 Jana Saout <jana@saout.de>
* Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
* Copyright (C) 2006-2017 Red Hat, Inc. All rights reserved.
* Copyright (C) 2013-2017 Milan Broz <gmazyland@gmail.com>
*
* This file is released under the GPL.
*/
#include <linux/completion.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/key.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/mempool.h>
#include <linux/slab.h>
#include <linux/crypto.h>
#include <linux/workqueue.h>
#include <linux/kthread.h>
#include <linux/backing-dev.h>
#include <linux/atomic.h>
#include <linux/scatterlist.h>
#include <linux/rbtree.h>
#include <linux/ctype.h>
#include <asm/page.h>
#include <asm/unaligned.h>
#include <crypto/hash.h>
#include <crypto/md5.h>
#include <crypto/algapi.h>
#include <crypto/skcipher.h>
#include <crypto/aead.h>
#include <crypto/authenc.h>
#include <linux/rtnetlink.h> /* for struct rtattr and RTA macros only */
#include <keys/user-type.h>
#include <linux/device-mapper.h>
#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;
union {
struct skcipher_request *req;
struct aead_request *req_aead;
} r;
};
/*
* per bio private data
*/
struct dm_crypt_io {
struct crypt_config *cc;
struct bio *base_bio;
u8 *integrity_metadata;
bool integrity_metadata_from_pool;
struct work_struct work;
struct convert_context ctx;
atomic_t io_pending;
blk_status_t error;
sector_t sector;
struct rb_node rb_node;
} CRYPTO_MINALIGN_ATTR;
struct dm_crypt_request {
struct convert_context *ctx;
struct scatterlist sg_in[4];
struct scatterlist sg_out[4];
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;
};
/*
* 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 };
enum cipher_flags {
CRYPT_MODE_INTEGRITY_AEAD, /* Use authenticated mode for cihper */
CRYPT_IV_LARGE_SECTORS, /* Calculate IV from sector_size, not 512B sectors */
};
/*
* 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,
* encryption requeusts/buffer pages and integrity tags
*/
mempool_t *req_pool;
mempool_t *page_pool;
mempool_t *tag_pool;
unsigned tag_pool_max_sectors;
struct percpu_counter n_allocated_pages;
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;
char *cipher_auth;
char *key_string;
const 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;
unsigned short int sector_size;
unsigned char sector_shift;
/* ESSIV: struct crypto_cipher *essiv_tfm */
void *iv_private;
union {
struct crypto_skcipher **tfms;
struct crypto_aead **tfms_aead;
} cipher_tfm;
unsigned tfms_count;
unsigned long cipher_flags;
/*
* 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 */
unsigned int key_mac_size; /* MAC key size for authenc(...) */
unsigned int integrity_tag_size;
unsigned int integrity_iv_size;
unsigned int on_disk_tag_size;
u8 *authenc_key; /* space for keys in authenc() format (if used) */
u8 key[0];
};
#define MIN_IOS 64
#define MAX_TAG_SIZE 480
#define POOL_ENTRY_SIZE 512
static DEFINE_SPINLOCK(dm_crypt_clients_lock);
static unsigned dm_crypt_clients_n = 0;
static volatile unsigned long dm_crypt_pages_per_client;
#define DM_CRYPT_MEMORY_PERCENT 2
#define DM_CRYPT_MIN_PAGES_PER_CLIENT (BIO_MAX_PAGES * 16)
static void clone_init(struct dm_crypt_io *, struct bio *);
static void kcryptd_queue_crypt(struct dm_crypt_io *io);
static struct scatterlist *crypt_get_sg_data(struct crypt_config *cc,
struct scatterlist *sg);
/*
* Use this to access cipher attributes that are independent of the key.
*/
static struct crypto_skcipher *any_tfm(struct crypt_config *cc)
{
return cc->cipher_tfm.tfms[0];
}
static struct crypto_aead *any_tfm_aead(struct crypt_config *cc)
{
return cc->cipher_tfm.tfms_aead[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.
*
* plain64be: the initial vector is the 64-bit big-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 int crypt_iv_plain64be_gen(struct crypt_config *cc, u8 *iv,
struct dm_crypt_request *dmreq)
{
memset(iv, 0, cc->iv_size);
/* iv_size is at least of size u64; usually it is 16 bytes */
*(__be64 *)&iv[cc->iv_size - sizeof(u64)] = cpu_to_be64(dmreq->iv_sector);
return 0;
}
/* 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;
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_SLEEP, NULL, NULL);
ahash_request_set_crypt(req, &sg, essiv->salt, cc->key_size);
err = 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;
}
/* Allocate the cipher for ESSIV */
static struct crypto_cipher *alloc_essiv_cipher(struct crypt_config *cc,
struct dm_target *ti,
const u8 *salt,
unsigned int 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) != cc->iv_size) {
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 = alloc_essiv_cipher(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;
if (cc->sector_size != (1 << SECTOR_SHIFT)) {
ti->error = "Unsupported sector size for LMK";
return -EINVAL;
}
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)
{
struct scatterlist *sg;
u8 *src;
int r = 0;
if (bio_data_dir(dmreq->ctx->bio_in) == WRITE) {
sg = crypt_get_sg_data(cc, dmreq->sg_in);
src = kmap_atomic(sg_page(sg));
r = crypt_iv_lmk_one(cc, iv, dmreq, src + sg->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)
{
struct scatterlist *sg;
u8 *dst;
int r;
if (bio_data_dir(dmreq->ctx->bio_in) == WRITE)
return 0;
sg = crypt_get_sg_data(cc, dmreq->sg_out);
dst = kmap_atomic(sg_page(sg));
r = crypt_iv_lmk_one(cc, iv, dmreq, dst + sg->offset);
/* Tweak the first block of plaintext sector */
if (!r)
crypto_xor(dst + sg->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->sector_size != (1 << SECTOR_SHIFT)) {
ti->error = "Unsupported sector size for TCW";
return -EINVAL;
}
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 */
crypto_xor_cpy(buf, tcw->whitening, (u8 *)&sector, 8);
crypto_xor_cpy(&buf[8], tcw->whitening + 8, (u8 *)&sector, 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 scatterlist *sg;
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) {
sg = crypt_get_sg_data(cc, dmreq->sg_in);
src = kmap_atomic(sg_page(sg));
r = crypt_iv_tcw_whitening(cc, dmreq, src + sg->offset);
kunmap_atomic(src);
}
/* Calculate IV */
crypto_xor_cpy(iv, tcw->iv_seed, (u8 *)&sector, 8);
if (cc->iv_size > 8)
crypto_xor_cpy(&iv[8], tcw->iv_seed + 8, (u8 *)&sector,
cc->iv_size - 8);
return r;
}
static int crypt_iv_tcw_post(struct crypt_config *cc, u8 *iv,
struct dm_crypt_request *dmreq)
{
struct scatterlist *sg;
u8 *dst;
int r;
if (bio_data_dir(dmreq->ctx->bio_in) != WRITE)
return 0;
/* Apply whitening on ciphertext */
sg = crypt_get_sg_data(cc, dmreq->sg_out);
dst = kmap_atomic(sg_page(sg));
r = crypt_iv_tcw_whitening(cc, dmreq, dst + sg->offset);
kunmap_atomic(dst);
return r;
}
static int crypt_iv_random_gen(struct crypt_config *cc, u8 *iv,
struct dm_crypt_request *dmreq)
{
/* Used only for writes, there must be an additional space to store IV */
get_random_bytes(iv, cc->iv_size);
return 0;
}
static const struct crypt_iv_operations crypt_iv_plain_ops = {
.generator = crypt_iv_plain_gen
};
static const struct crypt_iv_operations crypt_iv_plain64_ops = {
.generator = crypt_iv_plain64_gen
};
static const struct crypt_iv_operations crypt_iv_plain64be_ops = {
.generator = crypt_iv_plain64be_gen
};
static const 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 const struct crypt_iv_operations crypt_iv_benbi_ops = {
.ctr = crypt_iv_benbi_ctr,
.dtr = crypt_iv_benbi_dtr,
.generator = crypt_iv_benbi_gen
};
static const struct crypt_iv_operations crypt_iv_null_ops = {
.generator = crypt_iv_null_gen
};
static const 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 const 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 struct crypt_iv_operations crypt_iv_random_ops = {
.generator = crypt_iv_random_gen
};
/*
* Integrity extensions
*/
static bool crypt_integrity_aead(struct crypt_config *cc)
{
return test_bit(CRYPT_MODE_INTEGRITY_AEAD, &cc->cipher_flags);
}
static bool crypt_integrity_hmac(struct crypt_config *cc)
{
return crypt_integrity_aead(cc) && cc->key_mac_size;
}
/* Get sg containing data */
static struct scatterlist *crypt_get_sg_data(struct crypt_config *cc,
struct scatterlist *sg)
{
if (unlikely(crypt_integrity_aead(cc)))
return &sg[2];
return sg;
}
static int dm_crypt_integrity_io_alloc(struct dm_crypt_io *io, struct bio *bio)
{
struct bio_integrity_payload *bip;
unsigned int tag_len;
int ret;
if (!bio_sectors(bio) || !io->cc->on_disk_tag_size)
return 0;
bip = bio_integrity_alloc(bio, GFP_NOIO, 1);
if (IS_ERR(bip))
return PTR_ERR(bip);
tag_len = io->cc->on_disk_tag_size * bio_sectors(bio);
bip->bip_iter.bi_size = tag_len;
bip->bip_iter.bi_sector = io->cc->start + io->sector;
ret = bio_integrity_add_page(bio, virt_to_page(io->integrity_metadata),
tag_len, offset_in_page(io->integrity_metadata));
if (unlikely(ret != tag_len))
return -ENOMEM;
return 0;
}
static int crypt_integrity_ctr(struct crypt_config *cc, struct dm_target *ti)
{
#ifdef CONFIG_BLK_DEV_INTEGRITY
struct blk_integrity *bi = blk_get_integrity(cc->dev->bdev->bd_disk);
/* From now we require underlying device with our integrity profile */
if (!bi || strcasecmp(bi->profile->name, "DM-DIF-EXT-TAG")) {
ti->error = "Integrity profile not supported.";
return -EINVAL;
}
if (bi->tag_size != cc->on_disk_tag_size ||
bi->tuple_size != cc->on_disk_tag_size) {
ti->error = "Integrity profile tag size mismatch.";
return -EINVAL;
}
if (1 << bi->interval_exp != cc->sector_size) {
ti->error = "Integrity profile sector size mismatch.";
return -EINVAL;
}
if (crypt_integrity_aead(cc)) {
cc->integrity_tag_size = cc->on_disk_tag_size - cc->integrity_iv_size;
DMINFO("Integrity AEAD, tag size %u, IV size %u.",
cc->integrity_tag_size, cc->integrity_iv_size);
if (crypto_aead_setauthsize(any_tfm_aead(cc), cc->integrity_tag_size)) {
ti->error = "Integrity AEAD auth tag size is not supported.";
return -EINVAL;
}
} else if (cc->integrity_iv_size)
DMINFO("Additional per-sector space %u bytes for IV.",
cc->integrity_iv_size);
if ((cc->integrity_tag_size + cc->integrity_iv_size) != bi->tag_size) {
ti->error = "Not enough space for integrity tag in the profile.";
return -EINVAL;
}
return 0;
#else
ti->error = "Integrity profile not supported.";
return -EINVAL;
#endif
}
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,
void *req)
{
return (struct dm_crypt_request *)((char *)req + cc->dmreq_start);
}
static void *req_of_dmreq(struct crypt_config *cc, struct dm_crypt_request *dmreq)
{
return (void *)((char *)dmreq - cc->dmreq_start);
}
static u8 *iv_of_dmreq(struct crypt_config *cc,
struct dm_crypt_request *dmreq)
{
if (crypt_integrity_aead(cc))
return (u8 *)ALIGN((unsigned long)(dmreq + 1),
crypto_aead_alignmask(any_tfm_aead(cc)) + 1);
else
return (u8 *)ALIGN((unsigned long)(dmreq + 1),
crypto_skcipher_alignmask(any_tfm(cc)) + 1);
}
static u8 *org_iv_of_dmreq(struct crypt_config *cc,
struct dm_crypt_request *dmreq)
{
return iv_of_dmreq(cc, dmreq) + cc->iv_size;
}
static uint64_t *org_sector_of_dmreq(struct crypt_config *cc,
struct dm_crypt_request *dmreq)
{
u8 *ptr = iv_of_dmreq(cc, dmreq) + cc->iv_size + cc->iv_size;
return (uint64_t*) ptr;
}
static unsigned int *org_tag_of_dmreq(struct crypt_config *cc,
struct dm_crypt_request *dmreq)
{
u8 *ptr = iv_of_dmreq(cc, dmreq) + cc->iv_size +
cc->iv_size + sizeof(uint64_t);
return (unsigned int*)ptr;
}
static void *tag_from_dmreq(struct crypt_config *cc,
struct dm_crypt_request *dmreq)
{
struct convert_context *ctx = dmreq->ctx;
struct dm_crypt_io *io = container_of(ctx, struct dm_crypt_io, ctx);
return &io->integrity_metadata[*org_tag_of_dmreq(cc, dmreq) *
cc->on_disk_tag_size];
}
static void *iv_tag_from_dmreq(struct crypt_config *cc,
struct dm_crypt_request *dmreq)
{
return tag_from_dmreq(cc, dmreq) + cc->integrity_tag_size;
}
static int crypt_convert_block_aead(struct crypt_config *cc,
struct convert_context *ctx,
struct aead_request *req,
unsigned int tag_offset)
{
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, *org_iv, *tag_iv, *tag;
uint64_t *sector;
int r = 0;
BUG_ON(cc->integrity_iv_size && cc->integrity_iv_size != cc->iv_size);
/* Reject unexpected unaligned bio. */
if (unlikely(bv_in.bv_len & (cc->sector_size - 1)))
return -EIO;
dmreq = dmreq_of_req(cc, req);
dmreq->iv_sector = ctx->cc_sector;
if (test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags))
dmreq->iv_sector >>= cc->sector_shift;
dmreq->ctx = ctx;
*org_tag_of_dmreq(cc, dmreq) = tag_offset;
sector = org_sector_of_dmreq(cc, dmreq);
*sector = cpu_to_le64(ctx->cc_sector - cc->iv_offset);
iv = iv_of_dmreq(cc, dmreq);
org_iv = org_iv_of_dmreq(cc, dmreq);
tag = tag_from_dmreq(cc, dmreq);
tag_iv = iv_tag_from_dmreq(cc, dmreq);
/* AEAD request:
* |----- AAD -------|------ DATA -------|-- AUTH TAG --|
* | (authenticated) | (auth+encryption) | |
* | sector_LE | IV | sector in/out | tag in/out |
*/
sg_init_table(dmreq->sg_in, 4);
sg_set_buf(&dmreq->sg_in[0], sector, sizeof(uint64_t));
sg_set_buf(&dmreq->sg_in[1], org_iv, cc->iv_size);
sg_set_page(&dmreq->sg_in[2], bv_in.bv_page, cc->sector_size, bv_in.bv_offset);
sg_set_buf(&dmreq->sg_in[3], tag, cc->integrity_tag_size);
sg_init_table(dmreq->sg_out, 4);
sg_set_buf(&dmreq->sg_out[0], sector, sizeof(uint64_t));
sg_set_buf(&dmreq->sg_out[1], org_iv, cc->iv_size);
sg_set_page(&dmreq->sg_out[2], bv_out.bv_page, cc->sector_size, bv_out.bv_offset);
sg_set_buf(&dmreq->sg_out[3], tag, cc->integrity_tag_size);
if (cc->iv_gen_ops) {
/* For READs use IV stored in integrity metadata */
if (cc->integrity_iv_size && bio_data_dir(ctx->bio_in) != WRITE) {
memcpy(org_iv, tag_iv, cc->iv_size);
} else {
r = cc->iv_gen_ops->generator(cc, org_iv, dmreq);
if (r < 0)
return r;
/* Store generated IV in integrity metadata */
if (cc->integrity_iv_size)
memcpy(tag_iv, org_iv, cc->iv_size);
}
/* Working copy of IV, to be modified in crypto API */
memcpy(iv, org_iv, cc->iv_size);
}
aead_request_set_ad(req, sizeof(uint64_t) + cc->iv_size);
if (bio_data_dir(ctx->bio_in) == WRITE) {
aead_request_set_crypt(req, dmreq->sg_in, dmreq->sg_out,
cc->sector_size, iv);
r = crypto_aead_encrypt(req);
if (cc->integrity_tag_size + cc->integrity_iv_size != cc->on_disk_tag_size)
memset(tag + cc->integrity_tag_size + cc->integrity_iv_size, 0,
cc->on_disk_tag_size - (cc->integrity_tag_size + cc->integrity_iv_size));
} else {
aead_request_set_crypt(req, dmreq->sg_in, dmreq->sg_out,
cc->sector_size + cc->integrity_tag_size, iv);
r = crypto_aead_decrypt(req);
}
if (r == -EBADMSG)
DMERR_LIMIT("INTEGRITY AEAD ERROR, sector %llu",
(unsigned long long)le64_to_cpu(*sector));
if (!r && cc->iv_gen_ops && cc->iv_gen_ops->post)
r = cc->iv_gen_ops->post(cc, org_iv, dmreq);
bio_advance_iter(ctx->bio_in, &ctx->iter_in, cc->sector_size);
bio_advance_iter(ctx->bio_out, &ctx->iter_out, cc->sector_size);
return r;
}
static int crypt_convert_block_skcipher(struct crypt_config *cc,
struct convert_context *ctx,
struct skcipher_request *req,
unsigned int tag_offset)
{
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 scatterlist *sg_in, *sg_out;
struct dm_crypt_request *dmreq;
u8 *iv, *org_iv, *tag_iv;
uint64_t *sector;
int r = 0;
/* Reject unexpected unaligned bio. */
if (unlikely(bv_in.bv_len & (cc->sector_size - 1)))
return -EIO;
dmreq = dmreq_of_req(cc, req);
dmreq->iv_sector = ctx->cc_sector;
if (test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags))
dmreq->iv_sector >>= cc->sector_shift;
dmreq->ctx = ctx;
*org_tag_of_dmreq(cc, dmreq) = tag_offset;
iv = iv_of_dmreq(cc, dmreq);
org_iv = org_iv_of_dmreq(cc, dmreq);
tag_iv = iv_tag_from_dmreq(cc, dmreq);
sector = org_sector_of_dmreq(cc, dmreq);
*sector = cpu_to_le64(ctx->cc_sector - cc->iv_offset);
/* For skcipher we use only the first sg item */
sg_in = &dmreq->sg_in[0];
sg_out = &dmreq->sg_out[0];
sg_init_table(sg_in, 1);
sg_set_page(sg_in, bv_in.bv_page, cc->sector_size, bv_in.bv_offset);
sg_init_table(sg_out, 1);
sg_set_page(sg_out, bv_out.bv_page, cc->sector_size, bv_out.bv_offset);
if (cc->iv_gen_ops) {
/* For READs use IV stored in integrity metadata */
if (cc->integrity_iv_size && bio_data_dir(ctx->bio_in) != WRITE) {
memcpy(org_iv, tag_iv, cc->integrity_iv_size);
} else {
r = cc->iv_gen_ops->generator(cc, org_iv, dmreq);
if (r < 0)
return r;
/* Store generated IV in integrity metadata */
if (cc->integrity_iv_size)
memcpy(tag_iv, org_iv, cc->integrity_iv_size);
}
/* Working copy of IV, to be modified in crypto API */
memcpy(iv, org_iv, cc->iv_size);
}
skcipher_request_set_crypt(req, sg_in, sg_out, cc->sector_size, 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, org_iv, dmreq);
bio_advance_iter(ctx->bio_in, &ctx->iter_in, cc->sector_size);
bio_advance_iter(ctx->bio_out, &ctx->iter_out, cc->sector_size);
return r;
}
static void kcryptd_async_done(struct crypto_async_request *async_req,
int error);
static void crypt_alloc_req_skcipher(struct crypt_config *cc,
struct convert_context *ctx)
{
unsigned key_index = ctx->cc_sector & (cc->tfms_count - 1);
if (!ctx->r.req)
ctx->r.req = mempool_alloc(cc->req_pool, GFP_NOIO);
skcipher_request_set_tfm(ctx->r.req, cc->cipher_tfm.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->r.req,
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
kcryptd_async_done, dmreq_of_req(cc, ctx->r.req));
}
static void crypt_alloc_req_aead(struct crypt_config *cc,
struct convert_context *ctx)
{
if (!ctx->r.req_aead)
ctx->r.req_aead = mempool_alloc(cc->req_pool, GFP_NOIO);
aead_request_set_tfm(ctx->r.req_aead, cc->cipher_tfm.tfms_aead[0]);
/*
* Use REQ_MAY_BACKLOG so a cipher driver internally backlogs
* requests if driver request queue is full.
*/
aead_request_set_callback(ctx->r.req_aead,
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
kcryptd_async_done, dmreq_of_req(cc, ctx->r.req_aead));
}
static void crypt_alloc_req(struct crypt_config *cc,
struct convert_context *ctx)
{
if (crypt_integrity_aead(cc))
crypt_alloc_req_aead(cc, ctx);
else
crypt_alloc_req_skcipher(cc, ctx);
}
static void crypt_free_req_skcipher(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);
}
static void crypt_free_req_aead(struct crypt_config *cc,
struct aead_request *req, struct bio *base_bio)
{
struct dm_crypt_io *io = dm_per_bio_data(base_bio, cc->per_bio_data_size);
if ((struct aead_request *)(io + 1) != req)
mempool_free(req, cc->req_pool);
}
static void crypt_free_req(struct crypt_config *cc, void *req, struct bio *base_bio)
{
if (crypt_integrity_aead(cc))
crypt_free_req_aead(cc, req, base_bio);
else
crypt_free_req_skcipher(cc, req, base_bio);
}
/*
* Encrypt / decrypt data from one bio to another one (can be the same one)
*/
static blk_status_t crypt_convert(struct crypt_config *cc,
struct convert_context *ctx)
{
unsigned int tag_offset = 0;
unsigned int sector_step = cc->sector_size >> SECTOR_SHIFT;
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);
if (crypt_integrity_aead(cc))
r = crypt_convert_block_aead(cc, ctx, ctx->r.req_aead, tag_offset);
else
r = crypt_convert_block_skcipher(cc, ctx, ctx->r.req, tag_offset);
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->r.req = NULL;
ctx->cc_sector += sector_step;
tag_offset++;
continue;
/*
* The request was already processed (synchronously).
*/
case 0:
atomic_dec(&ctx->cc_pending);
ctx->cc_sector += sector_step;
tag_offset++;
cond_resched();
continue;
/*
* There was a data integrity error.
*/
case -EBADMSG:
atomic_dec(&ctx->cc_pending);
return BLK_STS_PROTECTION;
/*
* There was an error while processing the request.
*/
default:
atomic_dec(&ctx->cc_pending);
return BLK_STS_IOERR;
}
}
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;
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 out;
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;
bio_add_page(clone, page, len, 0);
remaining_size -= len;
}
/* Allocate space for integrity tags */
if (dm_crypt_integrity_io_alloc(io, clone)) {
crypt_free_buffer_pages(cc, clone);
bio_put(clone);
clone = NULL;
}
out:
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);
}
}
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.r.req = NULL;
io->integrity_metadata = NULL;
io->integrity_metadata_from_pool = false;
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;
blk_status_t error = io->error;
if (!atomic_dec_and_test(&io->io_pending))
return;
if (io->ctx.r.req)
crypt_free_req(cc, io->ctx.r.req, base_bio);
if (unlikely(io->integrity_metadata_from_pool))
mempool_free(io->integrity_metadata, io->cc->tag_pool);
else
kfree(io->integrity_metadata);
base_bio->bi_status = 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);
blk_status_t error;
/*
* free the processed pages
*/
if (rw == WRITE)
crypt_free_buffer_pages(cc, clone);
error = clone->bi_status;
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;
bio_set_dev(clone, cc->dev->bdev);
clone->bi_opf = io->base_bio->bi_opf;
}
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;
if (dm_crypt_integrity_io_alloc(io, clone)) {
crypt_dec_pending(io);
bio_put(clone);
return 1;
}
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 = BLK_STS_RESOURCE;
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_current_state(TASK_RUNNING);
remove_wait_queue(&cc->write_thread_wait, &wait);
break;
}
schedule();
set_current_state(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)) {
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;
blk_status_t 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 = BLK_STS_IOERR;
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 = r;
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;
blk_status_t r;
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)
io->error = r;
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, org_iv_of_dmreq(cc, dmreq), dmreq);
if (error == -EBADMSG) {
DMERR_LIMIT("INTEGRITY AEAD ERROR, sector %llu",
(unsigned long long)le64_to_cpu(*org_sector_of_dmreq(cc, dmreq)));
io->error = BLK_STS_PROTECTION;
} else if (error < 0)
io->error = BLK_STS_IOERR;
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);
}
static void crypt_free_tfms_aead(struct crypt_config *cc)
{
if (!cc->cipher_tfm.tfms_aead)
return;
if (cc->cipher_tfm.tfms_aead[0] && !IS_ERR(cc->cipher_tfm.tfms_aead[0])) {
crypto_free_aead(cc->cipher_tfm.tfms_aead[0]);
cc->cipher_tfm.tfms_aead[0] = NULL;
}
kfree(cc->cipher_tfm.tfms_aead);
cc->cipher_tfm.tfms_aead = NULL;
}
static void crypt_free_tfms_skcipher(struct crypt_config *cc)
{
unsigned i;
if (!cc->cipher_tfm.tfms)
return;
for (i = 0; i < cc->tfms_count; i++)
if (cc->cipher_tfm.tfms[i] && !IS_ERR(cc->cipher_tfm.tfms[i])) {
crypto_free_skcipher(cc->cipher_tfm.tfms[i]);
cc->cipher_tfm.tfms[i] = NULL;
}
kfree(cc->cipher_tfm.tfms);
cc->cipher_tfm.tfms = NULL;
}
static void crypt_free_tfms(struct crypt_config *cc)
{
if (crypt_integrity_aead(cc))
crypt_free_tfms_aead(cc);
else
crypt_free_tfms_skcipher(cc);
}
static int crypt_alloc_tfms_skcipher(struct crypt_config *cc, char *ciphermode)
{
unsigned i;
int err;
cc->cipher_tfm.tfms = kzalloc(cc->tfms_count *
sizeof(struct crypto_skcipher *), GFP_KERNEL);
if (!cc->cipher_tfm.tfms)
return -ENOMEM;
for (i = 0; i < cc->tfms_count; i++) {
cc->cipher_tfm.tfms[i] = crypto_alloc_skcipher(ciphermode, 0, 0);
if (IS_ERR(cc->cipher_tfm.tfms[i])) {
err = PTR_ERR(cc->cipher_tfm.tfms[i]);
crypt_free_tfms(cc);
return err;
}
}
return 0;
}
static int crypt_alloc_tfms_aead(struct crypt_config *cc, char *ciphermode)
{
int err;
cc->cipher_tfm.tfms = kmalloc(sizeof(struct crypto_aead *), GFP_KERNEL);
if (!cc->cipher_tfm.tfms)
return -ENOMEM;
cc->cipher_tfm.tfms_aead[0] = crypto_alloc_aead(ciphermode, 0, 0);
if (IS_ERR(cc->cipher_tfm.tfms_aead[0])) {
err = PTR_ERR(cc->cipher_tfm.tfms_aead[0]);
crypt_free_tfms(cc);
return err;
}
return 0;
}
static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode)
{
if (crypt_integrity_aead(cc))
return crypt_alloc_tfms_aead(cc, ciphermode);
else
return crypt_alloc_tfms_skcipher(cc, ciphermode);
}
static unsigned crypt_subkey_size(struct crypt_config *cc)
{
return (cc->key_size - cc->key_extra_size) >> ilog2(cc->tfms_count);
}
static unsigned crypt_authenckey_size(struct crypt_config *cc)
{
return crypt_subkey_size(cc) + RTA_SPACE(sizeof(struct crypto_authenc_key_param));
}
/*
* If AEAD is composed like authenc(hmac(sha256),xts(aes)),
* the key must be for some reason in special format.
* This funcion converts cc->key to this special format.
*/
static void crypt_copy_authenckey(char *p, const void *key,
unsigned enckeylen, unsigned authkeylen)
{
struct crypto_authenc_key_param *param;
struct rtattr *rta;
rta = (struct rtattr *)p;
param = RTA_DATA(rta);
param->enckeylen = cpu_to_be32(enckeylen);
rta->rta_len = RTA_LENGTH(sizeof(*param));
rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
p += RTA_SPACE(sizeof(*param));
memcpy(p, key + enckeylen, authkeylen);
p += authkeylen;
memcpy(p, key, enckeylen);
}
static int crypt_setkey(struct crypt_config *cc)
{
unsigned subkey_size;
int err = 0, i, r;
/* Ignore extra keys (which are used for IV etc) */
subkey_size = crypt_subkey_size(cc);
if (crypt_integrity_hmac(cc)) {
if (subkey_size < cc->key_mac_size)
return -EINVAL;
crypt_copy_authenckey(cc->authenc_key, cc->key,
subkey_size - cc->key_mac_size,
cc->key_mac_size);
}
for (i = 0; i < cc->tfms_count; i++) {
if (crypt_integrity_hmac(cc))
r = crypto_aead_setkey(cc->cipher_tfm.tfms_aead[i],
cc->authenc_key, crypt_authenckey_size(cc));
else if (crypt_integrity_aead(cc))
r = crypto_aead_setkey(cc->cipher_tfm.tfms_aead[i],
cc->key + (i * subkey_size),
subkey_size);
else
r = crypto_skcipher_setkey(cc->cipher_tfm.tfms[i],
cc->key + (i * subkey_size),
subkey_size);
if (r)
err = r;
}
if (crypt_integrity_hmac(cc))
memzero_explicit(cc->authenc_key, crypt_authenckey_size(cc));
return err;
}
#ifdef CONFIG_KEYS
static bool contains_whitespace(const char *str)
{
while (*str)
if (isspace(*str++))
return true;
return false;
}
static int crypt_set_keyring_key(struct crypt_config *cc, const char *key_string)
{
char *new_key_string, *key_desc;
int ret;
struct key *key;
const struct user_key_payload *ukp;
/*
* Reject key_string with whitespace. dm core currently lacks code for
* proper whitespace escaping in arguments on DM_TABLE_STATUS path.
*/
if (contains_whitespace(key_string)) {
DMERR("whitespace chars not allowed in key string");
return -EINVAL;
}
/* look for next ':' separating key_type from key_description */
key_desc = strpbrk(key_string, ":");
if (!key_desc || key_desc == key_string || !strlen(key_desc + 1))
return -EINVAL;
if (strncmp(key_string, "logon:", key_desc - key_string + 1) &&
strncmp(key_string, "user:", key_desc - key_string + 1))
return -EINVAL;
new_key_string = kstrdup(key_string, GFP_KERNEL);
if (!new_key_string)
return -ENOMEM;
key = request_key(key_string[0] == 'l' ? &key_type_logon : &key_type_user,
key_desc + 1, NULL);
if (IS_ERR(key)) {
kzfree(new_key_string);
return PTR_ERR(key);
}
down_read(&key->sem);
ukp = user_key_payload_locked(key);
if (!ukp) {
up_read(&key->sem);
key_put(key);
kzfree(new_key_string);
return -EKEYREVOKED;
}
if (cc->key_size != ukp->datalen) {
up_read(&key->sem);
key_put(key);
kzfree(new_key_string);
return -EINVAL;
}
memcpy(cc->key, ukp->data, cc->key_size);
up_read(&key->sem);
key_put(key);
/* clear the flag since following operations may invalidate previously valid key */
clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
ret = crypt_setkey(cc);
if (!ret) {
set_bit(DM_CRYPT_KEY_VALID, &cc->flags);
kzfree(cc->key_string);
cc->key_string = new_key_string;
} else
kzfree(new_key_string);
return ret;
}
static int get_key_size(char **key_string)
{
char *colon, dummy;
int ret;
if (*key_string[0] != ':')
return strlen(*key_string) >> 1;
/* look for next ':' in key string */
colon = strpbrk(*key_string + 1, ":");
if (!colon)
return -EINVAL;
if (sscanf(*key_string + 1, "%u%c", &ret, &dummy) != 2 || dummy != ':')
return -EINVAL;
*key_string = colon;
/* remaining key string should be :<logon|user>:<key_desc> */
return ret;
}
#else
static int crypt_set_keyring_key(struct crypt_config *cc, const char *key_string)
{
return -EINVAL;
}
static int get_key_size(char **key_string)
{
return (*key_string[0] == ':') ? -EINVAL : strlen(*key_string) >> 1;
}
#endif
static int crypt_set_key(struct crypt_config *cc, char *key)
{
int r = -EINVAL;
int key_string_len = strlen(key);
/* Hyphen (which gives a key_size of zero) means there is no key. */
if (!cc->key_size && strcmp(key, "-"))
goto out;
/* ':' means the key is in kernel keyring, short-circuit normal key processing */
if (key[0] == ':') {
r = crypt_set_keyring_key(cc, key + 1);
goto out;
}
/* clear the flag since following operations may invalidate previously valid key */
clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
/* wipe references to any kernel keyring key */
kzfree(cc->key_string);
cc->key_string = NULL;
/* Decode key from its hex representation. */
if (cc->key_size && hex2bin(cc->key, key, cc->key_size) < 0)
goto out;
r = crypt_setkey(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)
{
int r;
clear_bit(DM_CRYPT_KEY_VALID, &cc->flags);
get_random_bytes(&cc->key, cc->key_size);
kzfree(cc->key_string);
cc->key_string = NULL;
r = crypt_setkey(cc);
memset(&cc->key, 0, cc->key_size * sizeof(u8));
return r;
}
static void crypt_calculate_pages_per_client(void)
{
unsigned long pages = (totalram_pages - totalhigh_pages) * DM_CRYPT_MEMORY_PERCENT / 100;
if (!dm_crypt_clients_n)
return;
pages /= dm_crypt_clients_n;
if (pages < DM_CRYPT_MIN_PAGES_PER_CLIENT)
pages = DM_CRYPT_MIN_PAGES_PER_CLIENT;
dm_crypt_pages_per_client = pages;
}
static void *crypt_page_alloc(gfp_t gfp_mask, void *pool_data)
{
struct crypt_config *cc = pool_data;
struct page *page;
if (unlikely(percpu_counter_compare(&cc->n_allocated_pages, dm_crypt_pages_per_client) >= 0) &&
likely(gfp_mask & __GFP_NORETRY))
return NULL;
page = alloc_page(gfp_mask);
if (likely(page != NULL))
percpu_counter_add(&cc->n_allocated_pages, 1);
return page;
}
static void crypt_page_free(void *page, void *pool_data)
{
struct crypt_config *cc = pool_data;
__free_page(page);
percpu_counter_sub(&cc->n_allocated_pages, 1);
}
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);
mempool_destroy(cc->tag_pool);
if (cc->page_pool)
WARN_ON(percpu_counter_sum(&cc->n_allocated_pages) != 0);
percpu_counter_destroy(&cc->n_allocated_pages);
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);
kzfree(cc->key_string);
kzfree(cc->cipher_auth);
kzfree(cc->authenc_key);
mutex_destroy(&cc->bio_alloc_lock);
/* Must zero key material before freeing */
kzfree(cc);
spin_lock(&dm_crypt_clients_lock);
WARN_ON(!dm_crypt_clients_n);
dm_crypt_clients_n--;
crypt_calculate_pages_per_client();
spin_unlock(&dm_crypt_clients_lock);
}
static int crypt_ctr_ivmode(struct dm_target *ti, const char *ivmode)
{
struct crypt_config *cc = ti->private;
if (crypt_integrity_aead(cc))
cc->iv_size = crypto_aead_ivsize(any_tfm_aead(cc));
else
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, "plain64be") == 0)
cc->iv_gen_ops = &crypt_iv_plain64be_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 if (strcmp(ivmode, "random") == 0) {
cc->iv_gen_ops = &crypt_iv_random_ops;
/* Need storage space in integrity fields. */
cc->integrity_iv_size = cc->iv_size;
} else {
ti->error = "Invalid IV mode";
return -EINVAL;
}
return 0;
}
/*
* Workaround to parse cipher algorithm from crypto API spec.
* The cc->cipher is currently used only in ESSIV.
* This should be probably done by crypto-api calls (once available...)
*/
static int crypt_ctr_blkdev_cipher(struct crypt_config *cc)
{
const char *alg_name = NULL;
char *start, *end;
if (crypt_integrity_aead(cc)) {
alg_name = crypto_tfm_alg_name(crypto_aead_tfm(any_tfm_aead(cc)));
if (!alg_name)
return -EINVAL;
if (crypt_integrity_hmac(cc)) {
alg_name = strchr(alg_name, ',');
if (!alg_name)
return -EINVAL;
}
alg_name++;
} else {
alg_name = crypto_tfm_alg_name(crypto_skcipher_tfm(any_tfm(cc)));
if (!alg_name)
return -EINVAL;
}
start = strchr(alg_name, '(');
end = strchr(alg_name, ')');
if (!start && !end) {
cc->cipher = kstrdup(alg_name, GFP_KERNEL);
return cc->cipher ? 0 : -ENOMEM;
}
if (!start || !end || ++start >= end)
return -EINVAL;
cc->cipher = kzalloc(end - start + 1, GFP_KERNEL);
if (!cc->cipher)
return -ENOMEM;
strncpy(cc->cipher, start, end - start);
return 0;
}
/*
* Workaround to parse HMAC algorithm from AEAD crypto API spec.
* The HMAC is needed to calculate tag size (HMAC digest size).
* This should be probably done by crypto-api calls (once available...)
*/
static int crypt_ctr_auth_cipher(struct crypt_config *cc, char *cipher_api)
{
char *start, *end, *mac_alg = NULL;
struct crypto_ahash *mac;
if (!strstarts(cipher_api, "authenc("))
return 0;
start = strchr(cipher_api, '(');
end = strchr(cipher_api, ',');
if (!start || !end || ++start > end)
return -EINVAL;
mac_alg = kzalloc(end - start + 1, GFP_KERNEL);
if (!mac_alg)
return -ENOMEM;
strncpy(mac_alg, start, end - start);
mac = crypto_alloc_ahash(mac_alg, 0, 0);
kfree(mac_alg);
if (IS_ERR(mac))
return PTR_ERR(mac);
cc->key_mac_size = crypto_ahash_digestsize(mac);
crypto_free_ahash(mac);
cc->authenc_key = kmalloc(crypt_authenckey_size(cc), GFP_KERNEL);
if (!cc->authenc_key)
return -ENOMEM;
return 0;
}
static int crypt_ctr_cipher_new(struct dm_target *ti, char *cipher_in, char *key,
char **ivmode, char **ivopts)
{
struct crypt_config *cc = ti->private;
char *tmp, *cipher_api;
int ret = -EINVAL;
cc->tfms_count = 1;
/*
* New format (capi: prefix)
* capi:cipher_api_spec-iv:ivopts
*/
tmp = &cipher_in[strlen("capi:")];
cipher_api = strsep(&tmp, "-");
*ivmode = strsep(&tmp, ":");
*ivopts = tmp;
if (*ivmode && !strcmp(*ivmode, "lmk"))
cc->tfms_count = 64;
cc->key_parts = cc->tfms_count;
/* Allocate cipher */
ret = crypt_alloc_tfms(cc, cipher_api);
if (ret < 0) {
ti->error = "Error allocating crypto tfm";
return ret;
}
/* Alloc AEAD, can be used only in new format. */
if (crypt_integrity_aead(cc)) {
ret = crypt_ctr_auth_cipher(cc, cipher_api);
if (ret < 0) {
ti->error = "Invalid AEAD cipher spec";
return -ENOMEM;
}
cc->iv_size = crypto_aead_ivsize(any_tfm_aead(cc));
} else
cc->iv_size = crypto_skcipher_ivsize(any_tfm(cc));
ret = crypt_ctr_blkdev_cipher(cc);
if (ret < 0) {
ti->error = "Cannot allocate cipher string";
return -ENOMEM;
}
return 0;
}
static int crypt_ctr_cipher_old(struct dm_target *ti, char *cipher_in, char *key,
char **ivmode, char **ivopts)
{
struct crypt_config *cc = ti->private;
char *tmp, *cipher, *chainmode, *keycount;
char *cipher_api = NULL;
int ret = -EINVAL;
char dummy;
if (strchr(cipher_in, '(') || crypt_integrity_aead(cc)) {
ti->error = "Bad cipher specification";
return -EINVAL;
}
/*
* 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->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";
kfree(cipher_api);
return ret;
}
kfree(cipher_api);
return 0;
bad_mem:
ti->error = "Cannot allocate cipher strings";
return -ENOMEM;
}
static int crypt_ctr_cipher(struct dm_target *ti, char *cipher_in, char *key)
{
struct crypt_config *cc = ti->private;
char *ivmode = NULL, *ivopts = NULL;
int ret;
cc->cipher_string = kstrdup(cipher_in, GFP_KERNEL);
if (!cc->cipher_string) {
ti->error = "Cannot allocate cipher strings";
return -ENOMEM;
}
if (strstarts(cipher_in, "capi:"))
ret = crypt_ctr_cipher_new(ti, cipher_in, key, &ivmode, &ivopts);
else
ret = crypt_ctr_cipher_old(ti, cipher_in, key, &ivmode, &ivopts);
if (ret)
return ret;
/* Initialize IV */
ret = crypt_ctr_ivmode(ti, ivmode);
if (ret < 0)
return ret;
/* Initialize and set key */
ret = crypt_set_key(cc, key);
if (ret < 0) {
ti->error = "Error decoding and setting key";
return ret;
}
/* 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";
return ret;
}
}
/* 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";
return ret;
}
}
/* wipe the kernel key payload copy */
if (cc->key_string)
memset(cc->key, 0, cc->key_size * sizeof(u8));
return ret;
}
static int crypt_ctr_optional(struct dm_target *ti, unsigned int argc, char **argv)
{
struct crypt_config *cc = ti->private;
struct dm_arg_set as;
static const struct dm_arg _args[] = {
{0, 6, "Invalid number of feature args"},
};
unsigned int opt_params, val;
const char *opt_string, *sval;
char dummy;
int ret;
/* Optional parameters */
as.argc = argc;
as.argv = argv;
ret = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
if (ret)
return ret;
while (opt_params--) {
opt_string = dm_shift_arg(&as);
if (!opt_string) {
ti->error = "Not enough feature arguments";
return -EINVAL;
}
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 if (sscanf(opt_string, "integrity:%u:", &val) == 1) {
if (val == 0 || val > MAX_TAG_SIZE) {
ti->error = "Invalid integrity arguments";
return -EINVAL;
}
cc->on_disk_tag_size = val;
sval = strchr(opt_string + strlen("integrity:"), ':') + 1;
if (!strcasecmp(sval, "aead")) {
set_bit(CRYPT_MODE_INTEGRITY_AEAD, &cc->cipher_flags);
} else if (strcasecmp(sval, "none")) {
ti->error = "Unknown integrity profile";
return -EINVAL;
}
cc->cipher_auth = kstrdup(sval, GFP_KERNEL);
if (!cc->cipher_auth)
return -ENOMEM;
} else if (sscanf(opt_string, "sector_size:%hu%c", &cc->sector_size, &dummy) == 1) {
if (cc->sector_size < (1 << SECTOR_SHIFT) ||
cc->sector_size > 4096 ||
(cc->sector_size & (cc->sector_size - 1))) {
ti->error = "Invalid feature value for sector_size";
return -EINVAL;
}
if (ti->len & ((cc->sector_size >> SECTOR_SHIFT) - 1)) {
ti->error = "Device size is not multiple of sector_size feature";
return -EINVAL;
}
cc->sector_shift = __ffs(cc->sector_size) - SECTOR_SHIFT;
} else if (!strcasecmp(opt_string, "iv_large_sectors"))
set_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags);
else {
ti->error = "Invalid feature arguments";
return -EINVAL;
}
}
return 0;
}
/*
* Construct an encryption mapping:
* <cipher> [<key>|:<key_size>:<user|logon>:<key_description>] <iv_offset> <dev_path> <start>
*/
static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct crypt_config *cc;
int key_size;
unsigned int align_mask;
unsigned long long tmpll;
int ret;
size_t iv_size_padding, additional_req_size;
char dummy;
if (argc < 5) {
ti->error = "Not enough arguments";
return -EINVAL;
}
key_size = get_key_size(&argv[1]);
if (key_size < 0) {
ti->error = "Cannot parse key size";
return -EINVAL;
}
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;
cc->sector_size = (1 << SECTOR_SHIFT);
cc->sector_shift = 0;
ti->private = cc;
spin_lock(&dm_crypt_clients_lock);
dm_crypt_clients_n++;
crypt_calculate_pages_per_client();
spin_unlock(&dm_crypt_clients_lock);
ret = percpu_counter_init(&cc->n_allocated_pages, 0, GFP_KERNEL);
if (ret < 0)
goto bad;
/* Optional parameters need to be read before cipher constructor */
if (argc > 5) {
ret = crypt_ctr_optional(ti, argc - 5, &argv[5]);
if (ret)
goto bad;
}
ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
if (ret < 0)
goto bad;
if (crypt_integrity_aead(cc)) {
cc->dmreq_start = sizeof(struct aead_request);
cc->dmreq_start += crypto_aead_reqsize(any_tfm_aead(cc));
align_mask = crypto_aead_alignmask(any_tfm_aead(cc));
} else {
cc->dmreq_start = sizeof(struct skcipher_request);
cc->dmreq_start += crypto_skcipher_reqsize(any_tfm(cc));
align_mask = crypto_skcipher_alignmask(any_tfm(cc));
}
cc->dmreq_start = ALIGN(cc->dmreq_start, __alignof__(struct dm_crypt_request));
if (align_mask < CRYPTO_MINALIGN) {
/* Allocate the padding exactly */
iv_size_padding = -(cc->dmreq_start + sizeof(struct dm_crypt_request))
& align_mask;
} 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 = align_mask;
}
ret = -ENOMEM;
/* ...| IV + padding | original IV | original sec. number | bio tag offset | */
additional_req_size = sizeof(struct dm_crypt_request) +
iv_size_padding + cc->iv_size +
cc->iv_size +
sizeof(uint64_t) +
sizeof(unsigned int);
cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start + additional_req_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 + additional_req_size,
ARCH_KMALLOC_MINALIGN);
cc->page_pool = mempool_create(BIO_MAX_PAGES, crypt_page_alloc, crypt_page_free, cc);
if (!cc->page_pool) {
ti->error = "Cannot allocate page mempool";
goto bad;
}
cc->bs = bioset_create(MIN_IOS, 0, BIOSET_NEED_BVECS);
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) ||
(tmpll & ((cc->sector_size >> SECTOR_SHIFT) - 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;
if (crypt_integrity_aead(cc) || cc->integrity_iv_size) {
ret = crypt_integrity_ctr(cc, ti);
if (ret)
goto bad;
cc->tag_pool_max_sectors = POOL_ENTRY_SIZE / cc->on_disk_tag_size;
if (!cc->tag_pool_max_sectors)
cc->tag_pool_max_sectors = 1;
cc->tag_pool = mempool_create_kmalloc_pool(MIN_IOS,
cc->tag_pool_max_sectors * cc->on_disk_tag_size);
if (!cc->tag_pool) {
ti->error = "Cannot allocate integrity tags mempool";
ret = -ENOMEM;
goto bad;
}
cc->tag_pool_max_sectors <<= cc->sector_shift;
}
ret = -ENOMEM;
cc->io_queue = alloc_workqueue("kcryptd_io", WQ_HIGHPRI | WQ_CPU_INTENSIVE | 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_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1);
else
cc->crypt_queue = alloc_workqueue("kcryptd",
WQ_HIGHPRI | WQ_CPU_INTENSIVE | 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;
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_set_dev(bio, 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 || cc->on_disk_tag_size))
dm_accept_partial_bio(bio, ((BIO_MAX_PAGES << PAGE_SHIFT) >> SECTOR_SHIFT));
/*
* Ensure that bio is a multiple of internal sector encryption size
* and is aligned to this size as defined in IO hints.
*/
if (unlikely((bio->bi_iter.bi_sector & ((cc->sector_size >> SECTOR_SHIFT) - 1)) != 0))
return DM_MAPIO_KILL;
if (unlikely(bio->bi_iter.bi_size & (cc->sector_size - 1)))
return DM_MAPIO_KILL;
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));
if (cc->on_disk_tag_size) {
unsigned tag_len = cc->on_disk_tag_size * (bio_sectors(bio) >> cc->sector_shift);
if (unlikely(tag_len > KMALLOC_MAX_SIZE) ||
unlikely(!(io->integrity_metadata = kmalloc(tag_len,
GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
if (bio_sectors(bio) > cc->tag_pool_max_sectors)
dm_accept_partial_bio(bio, cc->tag_pool_max_sectors);
io->integrity_metadata = mempool_alloc(cc->tag_pool, GFP_NOIO);
io->integrity_metadata_from_pool = true;
}
}
if (crypt_integrity_aead(cc))
io->ctx.r.req_aead = (struct aead_request *)(io + 1);
else
io->ctx.r.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) {
if (cc->key_string)
DMEMIT(":%u:%s", cc->key_size, cc->key_string);
else
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);
num_feature_args += cc->sector_size != (1 << SECTOR_SHIFT);
num_feature_args += test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags);
if (cc->on_disk_tag_size)
num_feature_args++;
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");
if (cc->on_disk_tag_size)
DMEMIT(" integrity:%u:%s", cc->on_disk_tag_size, cc->cipher_auth);
if (cc->sector_size != (1 << SECTOR_SHIFT))
DMEMIT(" sector_size:%d", cc->sector_size);
if (test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags))
DMEMIT(" iv_large_sectors");
}
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>
* key wipe
*/
static int crypt_message(struct dm_target *ti, unsigned argc, char **argv,
char *result, unsigned maxlen)
{
struct crypt_config *cc = ti->private;
int key_size, 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")) {
/* The key size may not be changed. */
key_size = get_key_size(&argv[2]);
if (key_size < 0 || cc->key_size != key_size) {
memset(argv[2], '0', strlen(argv[2]));
return -EINVAL;
}
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);
/* wipe the kernel key payload copy */
if (cc->key_string)
memset(cc->key, 0, cc->key_size * sizeof(u8));
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)
{
struct crypt_config *cc = ti->private;
/*
* 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;
if (cc->sector_size != (1 << SECTOR_SHIFT)) {
limits->logical_block_size = cc->sector_size;
limits->physical_block_size = cc->sector_size;
blk_limits_io_min(limits, cc->sector_size);
}
}
static struct target_type crypt_target = {
.name = "crypt",
.version = {1, 18, 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 <jana@saout.de>");
MODULE_DESCRIPTION(DM_NAME " target for transparent encryption / decryption");
MODULE_LICENSE("GPL");
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