| Message ID | 20190628152112.914-5-ard.biesheuvel@linaro.org (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Mike Snitzer |
| Headers | show |
| Series | crypto: switch to crypto API for ESSIV generation | expand |
On 28/06/2019 17:21, Ard Biesheuvel wrote: > 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. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > drivers/md/dm-crypt.c | 200 ++++---------------- ... > -/* Wipe salt and reset key derived from volume key */ > -static int crypt_iv_essiv_wipe(struct crypt_config *cc) Do I understand it correctly, that this is now called inside the whole cipher set key in wipe command (in crypt_wipe_key())? (Wipe message is meant to suspend the device and wipe all key material from memory without actually destroying the device.) > -{ > - 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; > -} ... > @@ -2435,9 +2281,19 @@ static int crypt_ctr_cipher_new(struct dm_target *ti, char *cipher_in, char *key > } > > ret = crypt_ctr_blkdev_cipher(cc, cipher_api); > - if (ret < 0) { > - ti->error = "Cannot allocate cipher string"; > - return -ENOMEM; > + if (ret < 0) > + goto bad_mem; > + > + 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,%s)", > + cipher_api, cc->cipher, *ivopts); > + if (ret < 0 || ret >= CRYPTO_MAX_ALG_NAME) > + goto bad_mem; Hm, nitpicking, but goto from only one place while we have another -ENOMEM above... Just place this here without goto? > + ti->error = "Cannot allocate cipher string"; > + return -ENOMEM; Otherwise Reviewed-by: Milan Broz <gmazyland@gmail.com> Thanks, Milan -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
On Mon, 1 Jul 2019 at 10:59, Milan Broz <gmazyland@gmail.com> wrote: > > On 28/06/2019 17:21, Ard Biesheuvel wrote: > > 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. > > > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > > drivers/md/dm-crypt.c | 200 ++++---------------- > > ... > > > -/* Wipe salt and reset key derived from volume key */ > > -static int crypt_iv_essiv_wipe(struct crypt_config *cc) > > Do I understand it correctly, that this is now called inside the whole cipher > set key in wipe command (in crypt_wipe_key())? > > (Wipe message is meant to suspend the device and wipe all key material > from memory without actually destroying the device.) > Yes, setting the random key in wipe() triggers the SHA256 operation as normal, which is slightly wasteful but not a big deal imo. > > -{ > > - 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; > > -} > > ... > > > @@ -2435,9 +2281,19 @@ static int crypt_ctr_cipher_new(struct dm_target *ti, char *cipher_in, char *key > > } > > > > ret = crypt_ctr_blkdev_cipher(cc, cipher_api); > > - if (ret < 0) { > > - ti->error = "Cannot allocate cipher string"; > > - return -ENOMEM; > > + if (ret < 0) > > + goto bad_mem; > > + > > + 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,%s)", > > + cipher_api, cc->cipher, *ivopts); > > + if (ret < 0 || ret >= CRYPTO_MAX_ALG_NAME) > > + goto bad_mem; > > Hm, nitpicking, but goto from only one place while we have another -ENOMEM above... > > Just place this here without goto? > OK > > + ti->error = "Cannot allocate cipher string"; > > + return -ENOMEM; > > Otherwise > > Reviewed-by: Milan Broz <gmazyland@gmail.com> > > Thanks, > Milan -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
On Mon, 1 Jul 2019 at 10:59, Milan Broz <gmazyland@gmail.com> wrote: > > On 28/06/2019 17:21, Ard Biesheuvel wrote: > > 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. > > > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > > > drivers/md/dm-crypt.c | 200 ++++---------------- > > ... > > > -/* Wipe salt and reset key derived from volume key */ > > -static int crypt_iv_essiv_wipe(struct crypt_config *cc) > > Do I understand it correctly, that this is now called inside the whole cipher > set key in wipe command (in crypt_wipe_key())? > > (Wipe message is meant to suspend the device and wipe all key material > from memory without actually destroying the device.) > > > -{ > > - 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; > > -} > > ... > > > @@ -2435,9 +2281,19 @@ static int crypt_ctr_cipher_new(struct dm_target *ti, char *cipher_in, char *key > > } > > > > ret = crypt_ctr_blkdev_cipher(cc, cipher_api); > > - if (ret < 0) { > > - ti->error = "Cannot allocate cipher string"; > > - return -ENOMEM; > > + if (ret < 0) > > + goto bad_mem; > > + > > + 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,%s)", > > + cipher_api, cc->cipher, *ivopts); > > + if (ret < 0 || ret >= CRYPTO_MAX_ALG_NAME) > > + goto bad_mem; > > Hm, nitpicking, but goto from only one place while we have another -ENOMEM above... > > Just place this here without goto? > Actually, the bad_mem label is used 10 lines up as well. So I'll keep this goto in the next revision. > > + ti->error = "Cannot allocate cipher string"; > > + return -ENOMEM; > > Otherwise > > Reviewed-by: Milan Broz <gmazyland@gmail.com> > > Thanks, > Milan -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel
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 f001f1104cb5..e26a09c2d1a6 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; @@ -165,8 +159,6 @@ 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; @@ -323,157 +315,15 @@ 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; } @@ -854,10 +704,6 @@ 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 }; @@ -2397,7 +2243,7 @@ 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; @@ -2435,9 +2281,19 @@ static int crypt_ctr_cipher_new(struct dm_target *ti, char *cipher_in, char *key } ret = crypt_ctr_blkdev_cipher(cc, cipher_api); - if (ret < 0) { - ti->error = "Cannot allocate cipher string"; - return -ENOMEM; + if (ret < 0) + goto bad_mem; + + 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,%s)", + cipher_api, cc->cipher, *ivopts); + if (ret < 0 || ret >= CRYPTO_MAX_ALG_NAME) + goto bad_mem; + cipher_api = buf; } cc->key_parts = cc->tfms_count; @@ -2456,6 +2312,9 @@ static int crypt_ctr_cipher_new(struct dm_target *ti, char *cipher_in, char *key cc->iv_size = crypto_skcipher_ivsize(any_tfm(cc)); return 0; +bad_mem: + ti->error = "Cannot allocate cipher string"; + return -ENOMEM; } static int crypt_ctr_cipher_old(struct dm_target *ti, char *cipher_in, char *key, @@ -2515,9 +2374,20 @@ 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,%s)", chainmode, cipher, + 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; }
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. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> --- drivers/md/Kconfig | 1 + drivers/md/dm-crypt.c | 200 ++++---------------- 2 files changed, 36 insertions(+), 165 deletions(-)