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Using this more abstract interface allows the crypto subsystem to refactor the way ciphers are used, and to provide better testing coverage. Signed-off-by: Ard Biesheuvel --- drivers/md/Kconfig | 1 + drivers/md/dm-crypt.c | 137 ++++---------------- 2 files changed, 24 insertions(+), 114 deletions(-) -- 2.20.1 diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index 45254b3ef715..30ca87cf25db 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -271,6 +271,7 @@ config DM_CRYPT depends on BLK_DEV_DM select CRYPTO select CRYPTO_CBC + select CRYPTO_ESSIV ---help--- This device-mapper target allows you to create a device that transparently encrypts the data on it. You'll need to activate diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index 1b16d34bb785..b66ef3de835a 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -98,11 +98,6 @@ struct crypt_iv_operations { struct dm_crypt_request *dmreq); }; -struct iv_essiv_private { - struct crypto_shash *hash_tfm; - u8 *salt; -}; - struct iv_benbi_private { int shift; }; @@ -155,7 +150,6 @@ struct crypt_config { 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; @@ -165,7 +159,7 @@ struct crypt_config { unsigned short int sector_size; unsigned char sector_shift; - /* ESSIV: struct crypto_cipher *essiv_tfm */ + /* ESSIV: struct crypto_shash *essiv_tfm */ void *iv_private; union { struct crypto_skcipher **tfms; @@ -326,94 +320,27 @@ static int crypt_iv_plain64be_gen(struct crypt_config *cc, u8 *iv, /* 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; - SHASH_DESC_ON_STACK(desc, essiv->hash_tfm); - struct crypto_cipher *essiv_tfm; - int err; - - desc->tfm = essiv->hash_tfm; - - err = crypto_shash_digest(desc, cc->key, cc->key_size, essiv->salt); - shash_desc_zero(desc); - if (err) - return err; - - essiv_tfm = cc->iv_private; + struct crypto_shash *essiv_tfm = cc->iv_private; - err = crypto_cipher_setkey(essiv_tfm, essiv->salt, - crypto_shash_digestsize(essiv->hash_tfm)); - if (err) - return err; - - return 0; + return crypto_shash_setkey(essiv_tfm, cc->key, cc->key_size); } /* 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_shash_digestsize(essiv->hash_tfm); - struct crypto_cipher *essiv_tfm; - int r, err = 0; - - memset(essiv->salt, 0, salt_size); + struct crypto_shash *essiv_tfm; 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, 0); - 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; + return crypto_shash_setkey(essiv_tfm, NULL, 0); } 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_shash(essiv->hash_tfm); - essiv->hash_tfm = NULL; - - kzfree(essiv->salt); - essiv->salt = NULL; + struct crypto_shash *essiv_tfm; essiv_tfm = cc->iv_private; - if (essiv_tfm) - crypto_free_cipher(essiv_tfm); + crypto_free_shash(essiv_tfm); cc->iv_private = NULL; } @@ -421,9 +348,8 @@ static void crypt_iv_essiv_dtr(struct crypt_config *cc) 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_shash *hash_tfm = NULL; - u8 *salt = NULL; + struct crypto_shash *essiv_tfm = NULL; + u8 name[CRYPTO_MAX_ALG_NAME]; int err; if (!opts) { @@ -431,51 +357,34 @@ static int crypt_iv_essiv_ctr(struct crypt_config *cc, struct dm_target *ti, return -EINVAL; } - /* Allocate hash algorithm */ - hash_tfm = crypto_alloc_shash(opts, 0, 0); - if (IS_ERR(hash_tfm)) { - ti->error = "Error initializing ESSIV hash"; - err = PTR_ERR(hash_tfm); - goto bad; - } - - salt = kzalloc(crypto_shash_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; + snprintf(name, CRYPTO_MAX_ALG_NAME, "essiv(%s,%s)", cc->cipher, opts); - essiv_tfm = alloc_essiv_cipher(cc, ti, salt, - crypto_shash_digestsize(hash_tfm)); - if (IS_ERR(essiv_tfm)) { - crypt_iv_essiv_dtr(cc); + essiv_tfm = crypto_alloc_shash(name, 0, 0); + if (IS_ERR(essiv_tfm)) return PTR_ERR(essiv_tfm); + + err = crypto_shash_setkey(essiv_tfm, cc->key, cc->key_size); + if (err) { + ti->error = "Failed to set key for ESSIV cipher"; + crypto_free_shash(essiv_tfm); + return err; } + cc->iv_private = essiv_tfm; return 0; - -bad: - if (hash_tfm && !IS_ERR(hash_tfm)) - crypto_free_shash(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; + struct crypto_shash *essiv_tfm = cc->iv_private; + SHASH_DESC_ON_STACK(desc, essiv_tfm); memset(iv, 0, cc->iv_size); *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector); - crypto_cipher_encrypt_one(essiv_tfm, iv, iv); - - return 0; + desc->tfm = essiv_tfm; + return crypto_shash_digest(desc, iv, sizeof(__le64), iv); } static int crypt_iv_benbi_ctr(struct crypt_config *cc, struct dm_target *ti,