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[81.185.172.11]) by smtp.gmail.com with ESMTPSA id b26sm12693352wmj.14.2019.08.19.07.18.05 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 19 Aug 2019 07:18:12 -0700 (PDT) From: Ard Biesheuvel To: linux-crypto@vger.kernel.org Cc: Ard Biesheuvel , Herbert Xu , Eric Biggers , dm-devel@redhat.com, linux-fscrypt@vger.kernel.org, Gilad Ben-Yossef , Milan Broz Subject: [PATCH v13 5/6] md: dm-crypt: switch to ESSIV crypto API template Date: Mon, 19 Aug 2019 17:17:37 +0300 Message-Id: <20190819141738.1231-6-ard.biesheuvel@linaro.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190819141738.1231-1-ard.biesheuvel@linaro.org> References: <20190819141738.1231-1-ard.biesheuvel@linaro.org> Sender: linux-fscrypt-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Replace the explicit ESSIV handling in the dm-crypt driver with calls into the crypto API, which now possesses the capability to perform this processing within the crypto subsystem. Note that we reorder the AEAD cipher_api string parsing with the TFM instantiation: this is needed because cipher_api is mangled by the ESSIV handling, and throws off the parsing of "authenc(" otherwise. Signed-off-by: Ard Biesheuvel Acked-by: Mike Snitzer --- drivers/md/Kconfig | 1 + drivers/md/dm-crypt.c | 213 ++++---------------- 2 files changed, 44 insertions(+), 170 deletions(-) diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index 3834332f4963..b727e8f15264 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 d5216bcc4649..e3e6e111edfc 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; }; @@ -159,7 +154,6 @@ 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; @@ -170,8 +164,6 @@ struct crypt_config { 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; @@ -329,157 +321,15 @@ static int crypt_iv_plain64be_gen(struct crypt_config *cc, u8 *iv, 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; - 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; - - err = crypto_cipher_setkey(essiv_tfm, essiv->salt, - crypto_shash_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_shash_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, 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; -} - -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; - - 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_shash *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_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; - - essiv_tfm = alloc_essiv_cipher(cc, ti, salt, - crypto_shash_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_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; - + /* + * ESSIV encryption of the IV is now handled by the crypto API, + * so just pass the plain sector number here. + */ memset(iv, 0, cc->iv_size); *(__le64 *)iv = cpu_to_le64(dmreq->iv_sector); - crypto_cipher_encrypt_one(essiv_tfm, iv, iv); return 0; } @@ -921,10 +771,6 @@ static const struct crypt_iv_operations crypt_iv_plain64be_ops = { }; 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 }; @@ -2490,7 +2336,7 @@ 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; + char *tmp, *cipher_api, buf[CRYPTO_MAX_ALG_NAME]; int ret = -EINVAL; cc->tfms_count = 1; @@ -2516,9 +2362,32 @@ static int crypt_ctr_cipher_new(struct dm_target *ti, char *cipher_in, char *key /* The rest is crypto API spec */ cipher_api = tmp; + /* 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; + } + } + if (*ivmode && !strcmp(*ivmode, "lmk")) cc->tfms_count = 64; + if (*ivmode && !strcmp(*ivmode, "essiv")) { + if (!*ivopts) { + ti->error = "Digest algorithm missing for ESSIV mode"; + return -EINVAL; + } + ret = snprintf(buf, CRYPTO_MAX_ALG_NAME, "essiv(%s,%s)", + cipher_api, *ivopts); + if (ret < 0 || ret >= CRYPTO_MAX_ALG_NAME) { + ti->error = "Cannot allocate cipher string"; + return -ENOMEM; + } + cipher_api = buf; + } + cc->key_parts = cc->tfms_count; /* Allocate cipher */ @@ -2528,15 +2397,9 @@ static int crypt_ctr_cipher_new(struct dm_target *ti, char *cipher_in, char *key 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; - } + if (crypt_integrity_aead(cc)) cc->iv_size = crypto_aead_ivsize(any_tfm_aead(cc)); - } else + else cc->iv_size = crypto_skcipher_ivsize(any_tfm(cc)); ret = crypt_ctr_blkdev_cipher(cc); @@ -2605,9 +2468,19 @@ static int crypt_ctr_cipher_old(struct dm_target *ti, char *cipher_in, char *key if (!cipher_api) goto bad_mem; - ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME, - "%s(%s)", chainmode, cipher); - if (ret < 0) { + if (*ivmode && !strcmp(*ivmode, "essiv")) { + if (!*ivopts) { + ti->error = "Digest algorithm missing for ESSIV mode"; + kfree(cipher_api); + return -EINVAL; + } + ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME, + "essiv(%s(%s),%s)", chainmode, cipher, *ivopts); + } else { + ret = snprintf(cipher_api, CRYPTO_MAX_ALG_NAME, + "%s(%s)", chainmode, cipher); + } + if (ret < 0 || ret >= CRYPTO_MAX_ALG_NAME) { kfree(cipher_api); goto bad_mem; }