/*
* Copyright (C) 2003 Christophe Saout <christophe@saout.de>
+ * Copyright (C) 2004 Clemens Fruhwirth <clemens@endorphin.org>
*
* This file is released under the GPL.
*/
#include <linux/workqueue.h>
#include <asm/atomic.h>
#include <asm/scatterlist.h>
+#include <asm/page.h>
#include "dm.h"
struct bio *bio_out;
unsigned int offset_in;
unsigned int offset_out;
- int idx_in;
- int idx_out;
+ unsigned int idx_in;
+ unsigned int idx_out;
sector_t sector;
int write;
};
+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);
+ const char *(*status)(struct crypt_config *cc);
+ int (*generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
+};
+
/*
* Crypt: maps a linear range of a block device
* and encrypts / decrypts at the same time.
/*
* crypto related data
*/
- struct crypto_tfm *tfm;
+ struct crypt_iv_operations *iv_gen_ops;
+ char *iv_mode;
+ void *iv_gen_private;
sector_t iv_offset;
- int (*iv_generator)(struct crypt_config *cc, u8 *iv, sector_t sector);
- int iv_size;
- int key_size;
+ unsigned int iv_size;
+
+ struct crypto_tfm *tfm;
+ unsigned int key_size;
u8 key[0];
};
/*
- * Different IV generation algorithms
+ * Different IV generation algorithms:
+ *
+ * plain: the initial vector is the 32-bit low-endian version of the sector
+ * number, padded with zeros if neccessary.
+ *
+ * ess_iv: "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.
+ *
+ * plumb: unimplemented, see:
+ * http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/454
*/
-static int crypt_iv_plain(struct crypt_config *cc, u8 *iv, sector_t sector)
+
+static int crypt_iv_plain_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
{
+ memset(iv, 0, cc->iv_size);
*(u32 *)iv = cpu_to_le32(sector & 0xffffffff);
- if (cc->iv_size > sizeof(u32) / sizeof(u8))
- memset(iv + (sizeof(u32) / sizeof(u8)), 0,
- cc->iv_size - (sizeof(u32) / sizeof(u8)));
return 0;
}
+static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti,
+ const char *opts)
+{
+ struct crypto_tfm *essiv_tfm;
+ struct crypto_tfm *hash_tfm;
+ struct scatterlist sg;
+ unsigned int saltsize;
+ u8 *salt;
+
+ if (opts == NULL) {
+ ti->error = PFX "Digest algorithm missing for ESSIV mode";
+ return -EINVAL;
+ }
+
+ /* Hash the cipher key with the given hash algorithm */
+ hash_tfm = crypto_alloc_tfm(opts, 0);
+ if (hash_tfm == NULL) {
+ ti->error = PFX "Error initializing ESSIV hash";
+ return -EINVAL;
+ }
+
+ if (crypto_tfm_alg_type(hash_tfm) != CRYPTO_ALG_TYPE_DIGEST) {
+ ti->error = PFX "Expected digest algorithm for ESSIV hash";
+ crypto_free_tfm(hash_tfm);
+ return -EINVAL;
+ }
+
+ saltsize = crypto_tfm_alg_digestsize(hash_tfm);
+ salt = kmalloc(saltsize, GFP_KERNEL);
+ if (salt == NULL) {
+ ti->error = PFX "Error kmallocing salt storage in ESSIV";
+ crypto_free_tfm(hash_tfm);
+ return -ENOMEM;
+ }
+
+ sg.page = virt_to_page(cc->key);
+ sg.offset = offset_in_page(cc->key);
+ sg.length = cc->key_size;
+ crypto_digest_digest(hash_tfm, &sg, 1, salt);
+ crypto_free_tfm(hash_tfm);
+
+ /* Setup the essiv_tfm with the given salt */
+ essiv_tfm = crypto_alloc_tfm(crypto_tfm_alg_name(cc->tfm),
+ CRYPTO_TFM_MODE_ECB);
+ if (essiv_tfm == NULL) {
+ ti->error = PFX "Error allocating crypto tfm for ESSIV";
+ kfree(salt);
+ return -EINVAL;
+ }
+ if (crypto_tfm_alg_blocksize(essiv_tfm)
+ != crypto_tfm_alg_ivsize(cc->tfm)) {
+ ti->error = PFX "Block size of ESSIV cipher does "
+ "not match IV size of block cipher";
+ crypto_free_tfm(essiv_tfm);
+ kfree(salt);
+ return -EINVAL;
+ }
+ if (crypto_cipher_setkey(essiv_tfm, salt, saltsize) < 0) {
+ ti->error = PFX "Failed to set key for ESSIV cipher";
+ crypto_free_tfm(essiv_tfm);
+ kfree(salt);
+ return -EINVAL;
+ }
+ kfree(salt);
+
+ cc->iv_gen_private = (void *)essiv_tfm;
+ return 0;
+}
+
+static void crypt_iv_essiv_dtr(struct crypt_config *cc)
+{
+ crypto_free_tfm((struct crypto_tfm *)cc->iv_gen_private);
+ cc->iv_gen_private = NULL;
+}
+
+static int crypt_iv_essiv_gen(struct crypt_config *cc, u8 *iv, sector_t sector)
+{
+ struct scatterlist sg = { NULL, };
+
+ memset(iv, 0, cc->iv_size);
+ *(u64 *)iv = cpu_to_le64(sector);
+
+ sg.page = virt_to_page(iv);
+ sg.offset = offset_in_page(iv);
+ sg.length = cc->iv_size;
+ crypto_cipher_encrypt((struct crypto_tfm *)cc->iv_gen_private,
+ &sg, &sg, cc->iv_size);
+
+ return 0;
+}
+
+static struct crypt_iv_operations crypt_iv_plain_ops = {
+ .generator = crypt_iv_plain_gen
+};
+
+static struct crypt_iv_operations crypt_iv_essiv_ops = {
+ .ctr = crypt_iv_essiv_ctr,
+ .dtr = crypt_iv_essiv_dtr,
+ .generator = crypt_iv_essiv_gen
+};
+
+
static inline int
crypt_convert_scatterlist(struct crypt_config *cc, struct scatterlist *out,
struct scatterlist *in, unsigned int length,
u8 iv[cc->iv_size];
int r;
- if (cc->iv_generator) {
- r = cc->iv_generator(cc, iv, sector);
+ if (cc->iv_gen_ops) {
+ r = cc->iv_gen_ops->generator(cc, iv, sector);
if (r < 0)
return r;
*/
static struct bio *
crypt_alloc_buffer(struct crypt_config *cc, unsigned int size,
- struct bio *base_bio, int *bio_vec_idx)
+ struct bio *base_bio, unsigned int *bio_vec_idx)
{
struct bio *bio;
- int nr_iovecs = dm_div_up(size, PAGE_SIZE);
+ unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
int gfp_mask = GFP_NOIO | __GFP_HIGHMEM;
- int flags = current->flags;
- int i;
+ unsigned long flags = current->flags;
+ unsigned int i;
/*
* Tell VM to act less aggressively and fail earlier.
static void crypt_free_buffer_pages(struct crypt_config *cc,
struct bio *bio, unsigned int bytes)
{
- unsigned int start, end;
+ unsigned int i, start, end;
struct bio_vec *bv;
- int i;
/*
* This is ugly, but Jens Axboe thinks that using bi_idx in the
/*
* Decode key from its hex representation
*/
-static int crypt_decode_key(u8 *key, char *hex, int size)
+static int crypt_decode_key(u8 *key, char *hex, unsigned int size)
{
char buffer[3];
char *endp;
- int i;
+ unsigned int i;
buffer[2] = '\0';
/*
* Encode key into its hex representation
*/
-static void crypt_encode_key(char *hex, u8 *key, int size)
+static void crypt_encode_key(char *hex, u8 *key, unsigned int size)
{
- int i;
+ unsigned int i;
for(i = 0; i < size; i++) {
sprintf(hex, "%02x", *key);
struct crypto_tfm *tfm;
char *tmp;
char *cipher;
- char *mode;
- int crypto_flags;
- int key_size;
+ char *chainmode;
+ char *ivmode;
+ char *ivopts;
+ unsigned int crypto_flags;
+ unsigned int key_size;
if (argc != 5) {
ti->error = PFX "Not enough arguments";
tmp = argv[0];
cipher = strsep(&tmp, "-");
- mode = strsep(&tmp, "-");
+ chainmode = strsep(&tmp, "-");
+ ivopts = strsep(&tmp, "-");
+ ivmode = strsep(&ivopts, ":");
if (tmp)
DMWARN(PFX "Unexpected additional cipher options");
return -ENOMEM;
}
- if (!mode || strcmp(mode, "plain") == 0)
- cc->iv_generator = crypt_iv_plain;
- else if (strcmp(mode, "ecb") == 0)
- cc->iv_generator = NULL;
- else {
- ti->error = PFX "Invalid chaining mode";
+ cc->key_size = key_size;
+ if ((!key_size && strcmp(argv[1], "-") != 0) ||
+ (key_size && crypt_decode_key(cc->key, argv[1], key_size) < 0)) {
+ ti->error = PFX "Error decoding key";
goto bad1;
}
- if (cc->iv_generator)
+ /* Compatiblity mode for old dm-crypt cipher strings */
+ if (!chainmode || (strcmp(chainmode, "plain") == 0 && !ivmode)) {
+ chainmode = "cbc";
+ ivmode = "plain";
+ }
+
+ /* Choose crypto_flags according to chainmode */
+ if (strcmp(chainmode, "cbc") == 0)
crypto_flags = CRYPTO_TFM_MODE_CBC;
- else
+ else if (strcmp(chainmode, "ecb") == 0)
crypto_flags = CRYPTO_TFM_MODE_ECB;
+ else {
+ ti->error = PFX "Unknown chaining mode";
+ goto bad1;
+ }
+
+ if (crypto_flags != CRYPTO_TFM_MODE_ECB && !ivmode) {
+ ti->error = PFX "This chaining mode requires an IV mechanism";
+ goto bad1;
+ }
tfm = crypto_alloc_tfm(cipher, crypto_flags);
if (!tfm) {
goto bad2;
}
+ cc->tfm = tfm;
+
+ /*
+ * Choose ivmode. Valid modes: "plain", "essiv:<esshash>".
+ * 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 {
+ ti->error = PFX "Invalid IV mode";
+ goto bad2;
+ }
+
+ if (cc->iv_gen_ops && cc->iv_gen_ops->ctr &&
+ cc->iv_gen_ops->ctr(cc, ti, ivopts) < 0)
+ goto bad2;
+
if (tfm->crt_cipher.cit_decrypt_iv && tfm->crt_cipher.cit_encrypt_iv)
- /* at least a 32 bit sector number should fit in our buffer */
+ /* at least a 64 bit sector number should fit in our buffer */
cc->iv_size = max(crypto_tfm_alg_ivsize(tfm),
- (unsigned int)(sizeof(u32) / sizeof(u8)));
+ (unsigned int)(sizeof(u64) / sizeof(u8)));
else {
cc->iv_size = 0;
- if (cc->iv_generator) {
+ if (cc->iv_gen_ops) {
DMWARN(PFX "Selected cipher does not support IVs");
- cc->iv_generator = NULL;
+ if (cc->iv_gen_ops->dtr)
+ cc->iv_gen_ops->dtr(cc);
+ cc->iv_gen_ops = NULL;
}
}
mempool_free_slab, _crypt_io_pool);
if (!cc->io_pool) {
ti->error = PFX "Cannot allocate crypt io mempool";
- goto bad2;
+ goto bad3;
}
cc->page_pool = mempool_create(MIN_POOL_PAGES, mempool_alloc_page,
mempool_free_page, NULL);
if (!cc->page_pool) {
ti->error = PFX "Cannot allocate page mempool";
- goto bad3;
- }
-
- cc->tfm = tfm;
- cc->key_size = key_size;
- if ((key_size == 0 && strcmp(argv[1], "-") != 0)
- || crypt_decode_key(cc->key, argv[1], key_size) < 0) {
- ti->error = PFX "Error decoding key";
goto bad4;
}
if (tfm->crt_cipher.cit_setkey(tfm, cc->key, key_size) < 0) {
ti->error = PFX "Error setting key";
- goto bad4;
+ goto bad5;
}
if (sscanf(argv[2], SECTOR_FORMAT, &cc->iv_offset) != 1) {
ti->error = PFX "Invalid iv_offset sector";
- goto bad4;
+ goto bad5;
}
if (sscanf(argv[4], SECTOR_FORMAT, &cc->start) != 1) {
ti->error = PFX "Invalid device sector";
- goto bad4;
+ goto bad5;
}
if (dm_get_device(ti, argv[3], cc->start, ti->len,
dm_table_get_mode(ti->table), &cc->dev)) {
ti->error = PFX "Device lookup failed";
- goto bad4;
+ goto bad5;
}
+ 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 = PFX "Error kmallocing iv_mode string";
+ goto bad5;
+ }
+ strcpy(cc->iv_mode, ivmode);
+ } else
+ cc->iv_mode = NULL;
+
ti->private = cc;
return 0;
-bad4:
+bad5:
mempool_destroy(cc->page_pool);
-bad3:
+bad4:
mempool_destroy(cc->io_pool);
+bad3:
+ if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
+ cc->iv_gen_ops->dtr(cc);
bad2:
crypto_free_tfm(tfm);
bad1:
mempool_destroy(cc->page_pool);
mempool_destroy(cc->io_pool);
+ if (cc->iv_mode)
+ kfree(cc->iv_mode);
+ if (cc->iv_gen_ops && cc->iv_gen_ops->dtr)
+ cc->iv_gen_ops->dtr(cc);
crypto_free_tfm(cc->tfm);
dm_put_device(ti, cc->dev);
kfree(cc);
static inline struct bio *
crypt_clone(struct crypt_config *cc, struct crypt_io *io, struct bio *bio,
- sector_t sector, int *bvec_idx, struct convert_context *ctx)
+ sector_t sector, unsigned int *bvec_idx,
+ struct convert_context *ctx)
{
struct bio *clone;
struct bio *clone;
unsigned int remaining = bio->bi_size;
sector_t sector = bio->bi_sector - ti->begin;
- int bvec_idx = 0;
+ unsigned int bvec_idx = 0;
io->target = ti;
io->bio = bio;
struct crypt_config *cc = (struct crypt_config *) ti->private;
char buffer[32];
const char *cipher;
- const char *mode = NULL;
- int offset;
+ const char *chainmode = NULL;
+ unsigned int sz = 0;
switch (type) {
case STATUSTYPE_INFO:
switch(cc->tfm->crt_cipher.cit_mode) {
case CRYPTO_TFM_MODE_CBC:
- mode = "plain";
+ chainmode = "cbc";
break;
case CRYPTO_TFM_MODE_ECB:
- mode = "ecb";
+ chainmode = "ecb";
break;
default:
BUG();
}
- snprintf(result, maxlen, "%s-%s ", cipher, mode);
- offset = strlen(result);
+ if (cc->iv_mode)
+ DMEMIT("%s-%s-%s ", cipher, chainmode, cc->iv_mode);
+ else
+ DMEMIT("%s-%s ", cipher, chainmode);
if (cc->key_size > 0) {
- if ((maxlen - offset) < ((cc->key_size << 1) + 1))
+ if ((maxlen - sz) < ((cc->key_size << 1) + 1))
return -ENOMEM;
- crypt_encode_key(result + offset, cc->key, cc->key_size);
- offset += cc->key_size << 1;
+ crypt_encode_key(result + sz, cc->key, cc->key_size);
+ sz += cc->key_size << 1;
} else {
- if (offset >= maxlen)
+ if (sz >= maxlen)
return -ENOMEM;
- result[offset++] = '-';
+ result[sz++] = '-';
}
format_dev_t(buffer, cc->dev->bdev->bd_dev);
- snprintf(result + offset, maxlen - offset, " " SECTOR_FORMAT
- " %s " SECTOR_FORMAT, cc->iv_offset,
- buffer, cc->start);
+ DMEMIT(" " SECTOR_FORMAT " %s " SECTOR_FORMAT,
+ cc->iv_offset, buffer, cc->start);
break;
}
return 0;
static struct target_type crypt_target = {
.name = "crypt",
- .version= {1, 0, 0},
+ .version= {1, 1, 0},
.module = THIS_MODULE,
.ctr = crypt_ctr,
.dtr = crypt_dtr,
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