[dm-devel] [PATCH 1/1] dm crypt: Add inline encryption support
Damien Le Moal
damien.lemoal at opensource.wdc.com
Fri Jan 14 08:14:32 UTC 2022
On 2022/01/14 4:11, Israel Rukshin wrote:
> Using inline encryption means that the block layer handles the
> decryption/encryption as part of the bio, instead of dm-crypt
> doing the crypto by itself via Linux's crypto API. This model
> is needed to take advantage of the inline encryption hardware
> on the market.
>
> To use inline encryption, the new dm-crypt optional parameter
> "inline_crypt" should be set for the configured mapping. Afterwards,
> dm-crypt will provide the crypto parameters to the block layer by
> creating a cypto profile and by filling the bios with crypto context.
> In case the block device or the fallback algorithm doesn't support
> this feature, the mapping will fail.
>
> Signed-off-by: Israel Rukshin <israelr at nvidia.com>
> ---
> block/blk-crypto.c | 3 +
> drivers/md/dm-crypt.c | 202 ++++++++++++++++++++++++++++++++++++------
> 2 files changed, 180 insertions(+), 25 deletions(-)
>
> diff --git a/block/blk-crypto.c b/block/blk-crypto.c
> index 1c08d3b6e24a..65f13549eb5f 100644
> --- a/block/blk-crypto.c
> +++ b/block/blk-crypto.c
> @@ -102,6 +102,7 @@ void bio_crypt_set_ctx(struct bio *bio, const struct blk_crypto_key *key,
>
> bio->bi_crypt_context = bc;
> }
> +EXPORT_SYMBOL_GPL(bio_crypt_set_ctx);
>
> void __bio_crypt_free_ctx(struct bio *bio)
> {
> @@ -370,6 +371,7 @@ int blk_crypto_init_key(struct blk_crypto_key *blk_key,
>
> return 0;
> }
> +EXPORT_SYMBOL_GPL(blk_crypto_init_key);
>
> /*
> * Check if bios with @cfg can be en/decrypted by blk-crypto (i.e. either the
> @@ -411,6 +413,7 @@ int blk_crypto_start_using_key(const struct blk_crypto_key *key,
> }
> return blk_crypto_fallback_start_using_mode(key->crypto_cfg.crypto_mode);
> }
> +EXPORT_SYMBOL_GPL(blk_crypto_start_using_key);
>
> /**
> * blk_crypto_evict_key() - Evict a key from any inline encryption hardware
These changes could probably go into a separate prep patch.
> diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
> index d4ae31558826..4c0e1904942b 100644
> --- a/drivers/md/dm-crypt.c
> +++ b/drivers/md/dm-crypt.c
> @@ -39,6 +39,7 @@
> #include <keys/user-type.h>
> #include <keys/encrypted-type.h>
> #include <keys/trusted-type.h>
> +#include <linux/blk-crypto.h>
>
> #include <linux/device-mapper.h>
>
> @@ -134,7 +135,7 @@ struct iv_elephant_private {
> enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID,
> DM_CRYPT_SAME_CPU, DM_CRYPT_NO_OFFLOAD,
> DM_CRYPT_NO_READ_WORKQUEUE, DM_CRYPT_NO_WRITE_WORKQUEUE,
> - DM_CRYPT_WRITE_INLINE };
> + DM_CRYPT_WRITE_INLINE, DM_CRYPT_INLINE_ENCRYPTION };
>
> enum cipher_flags {
> CRYPT_MODE_INTEGRITY_AEAD, /* Use authenticated mode for cipher */
> @@ -220,6 +221,11 @@ struct crypt_config {
> struct bio_set bs;
> struct mutex bio_alloc_lock;
>
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> + enum blk_crypto_mode_num crypto_mode;
> + enum blk_crypto_key_type key_type;
> + struct blk_crypto_key *blk_key;
> +#endif
> u8 *authenc_key; /* space for keys in authenc() format (if used) */
> u8 key[];
> };
> @@ -2383,11 +2389,103 @@ static void crypt_copy_authenckey(char *p, const void *key,
> memcpy(p, key, enckeylen);
> }
>
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> +static int crypt_select_inline_crypt_mode(struct dm_target *ti, char *cipher,
> + char *ivmode)
> +{
> + struct crypt_config *cc = ti->private;
> +
> + if (strcmp(cipher, "xts(aes)") == 0) {
> + cc->crypto_mode = BLK_ENCRYPTION_MODE_AES_256_XTS;
> + cc->key_type = BLK_CRYPTO_KEY_TYPE_STANDARD;
> + } else if (strcmp(cipher, "xts(paes)") == 0) {
> + cc->crypto_mode = BLK_ENCRYPTION_MODE_AES_256_XTS;
> + cc->key_type = BLK_CRYPTO_KEY_TYPE_HW_WRAPPED;
> + } else {
> + ti->error = "Invalid cipher for inline_crypt";
> + return -EINVAL;
> + }
> +
> + if (ivmode == NULL || (strcmp(ivmode, "plain64") == 0)) {
> + cc->iv_size = 8;
> + } else {
> + ti->error = "Invalid IV mode for inline_crypt";
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static int crypt_prepare_inline_crypt_key(struct crypt_config *cc)
> +{
> + int ret;
> +
> + cc->blk_key = kzalloc(sizeof(*cc->blk_key), GFP_KERNEL);
> + if (!cc->blk_key)
> + return -ENOMEM;
> +
> + ret = blk_crypto_init_key(cc->blk_key, cc->key, cc->key_size,
> + cc->key_type, cc->crypto_mode, cc->iv_size,
> + cc->sector_size);
> + if (ret) {
> + DMERR("Failed to init inline encryption key");
> + goto bad_key;
> + }
> +
> + ret = blk_crypto_start_using_key(cc->blk_key,
> + bdev_get_queue(cc->dev->bdev));
> + if (ret) {
> + DMERR("Failed to use inline encryption key");
> + goto bad_key;
> + }
> +
> + return 0;
> +bad_key:
> + kfree_sensitive(cc->blk_key);
> + cc->blk_key = NULL;
> + return ret;
> +}
> +
> +static void crypt_destroy_inline_crypt_key(struct crypt_config *cc)
> +{
> + if (cc->blk_key) {
> + blk_crypto_evict_key(bdev_get_queue(cc->dev->bdev),
> + cc->blk_key);
> + kfree_sensitive(cc->blk_key);
> + cc->blk_key = NULL;
> + }
> +}
> +
> +static void crypt_inline_encrypt_submit(struct dm_target *ti, struct bio *bio)
> +{
> + struct crypt_config *cc = ti->private;
> + u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE];
> +
> + bio_set_dev(bio, cc->dev->bdev);
> + if (bio_sectors(bio)) {
> + memset(dun, 0, BLK_CRYPTO_MAX_IV_SIZE);
> + bio->bi_iter.bi_sector = cc->start +
> + dm_target_offset(ti, bio->bi_iter.bi_sector);
> + dun[0] = le64_to_cpu(bio->bi_iter.bi_sector + cc->iv_offset);
> + bio_crypt_set_ctx(bio, cc->blk_key, dun, GFP_KERNEL);
> + }
> +
> + submit_bio_noacct(bio);
> +}
#else
define the above functions as empty (see below).
> +#endif
> +
> static int crypt_setkey(struct crypt_config *cc)
> {
> unsigned subkey_size;
> int err = 0, i, r;
>
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> + if (test_bit(DM_CRYPT_INLINE_ENCRYPTION, &cc->flags)) {
> + crypt_destroy_inline_crypt_key(cc);
> + return crypt_prepare_inline_crypt_key(cc);
> + }
> +#endif
You could avoid the ifdef here using IS_ENABLED(CONFIG_BLK_INLINE_ENCRYPTION)
directly in the if condition. That will make the code cleaner. That said, since
DM_CRYPT_INLINE_ENCRYPTION can only be set if CONFIG_BLK_INLINE_ENCRYPTION is
enabled, I am not sure if the ifdef buys you much in the
!CONFIG_BLK_INLINE_ENCRYPTION case.
> +
> /* Ignore extra keys (which are used for IV etc) */
> subkey_size = crypt_subkey_size(cc);
>
> @@ -2648,6 +2746,15 @@ static int crypt_wipe_key(struct crypt_config *cc)
>
> kfree_sensitive(cc->key_string);
> cc->key_string = NULL;
> +
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> + if (test_bit(DM_CRYPT_INLINE_ENCRYPTION, &cc->flags)) {
> + crypt_destroy_inline_crypt_key(cc);
> + memset(&cc->key, 0, cc->key_size * sizeof(u8));
> + return 0;
> + }
> +#endif
same comment as above and for most of the following ifdef additions.
> +
> r = crypt_setkey(cc);
> memset(&cc->key, 0, cc->key_size * sizeof(u8));
>
> @@ -2713,6 +2820,10 @@ static void crypt_dtr(struct dm_target *ti)
> if (cc->crypt_queue)
> destroy_workqueue(cc->crypt_queue);
>
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> + crypt_destroy_inline_crypt_key(cc);
> +#endif
You can avoid the ifdef here if this function is defined as empty in the
!CONFIG_BLK_INLINE_ENCRYPTION case (see above the comment about #else).
> +
> crypt_free_tfms(cc);
>
> bioset_exit(&cc->bs);
> @@ -2888,6 +2999,11 @@ static int crypt_ctr_cipher_new(struct dm_target *ti, char *cipher_in, char *key
> /* The rest is crypto API spec */
> cipher_api = tmp;
>
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> + if (test_bit(DM_CRYPT_INLINE_ENCRYPTION, &cc->flags))
> + return crypt_select_inline_crypt_mode(ti, cipher_api, *ivmode);
> +#endif
> +
> /* Alloc AEAD, can be used only in new format. */
> if (crypt_integrity_aead(cc)) {
> ret = crypt_ctr_auth_cipher(cc, cipher_api);
> @@ -3001,6 +3117,11 @@ static int crypt_ctr_cipher_old(struct dm_target *ti, char *cipher_in, char *key
> goto bad_mem;
> }
>
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> + if (test_bit(DM_CRYPT_INLINE_ENCRYPTION, &cc->flags))
> + return crypt_select_inline_crypt_mode(ti, cipher_api, *ivmode);
> +#endif
> +
> /* Allocate cipher */
> ret = crypt_alloc_tfms(cc, cipher_api);
> if (ret < 0) {
> @@ -3036,9 +3157,11 @@ static int crypt_ctr_cipher(struct dm_target *ti, char *cipher_in, char *key)
> return ret;
>
> /* Initialize IV */
> - ret = crypt_ctr_ivmode(ti, ivmode);
> - if (ret < 0)
> - return ret;
> + if (!test_bit(DM_CRYPT_INLINE_ENCRYPTION, &cc->flags)) {
> + ret = crypt_ctr_ivmode(ti, ivmode);
> + if (ret < 0)
> + return ret;
> + }
>
> /* Initialize and set key */
> ret = crypt_set_key(cc, key);
> @@ -3111,6 +3234,10 @@ static int crypt_ctr_optional(struct dm_target *ti, unsigned int argc, char **ar
> set_bit(DM_CRYPT_NO_READ_WORKQUEUE, &cc->flags);
> else if (!strcasecmp(opt_string, "no_write_workqueue"))
> set_bit(DM_CRYPT_NO_WRITE_WORKQUEUE, &cc->flags);
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> + else if (!strcasecmp(opt_string, "inline_crypt"))
> + set_bit(DM_CRYPT_INLINE_ENCRYPTION, &cc->flags);
> +#endif
May be add a warning here for the !CONFIG_BLK_INLINE_ENCRYPTION case ?
> else if (sscanf(opt_string, "integrity:%u:", &val) == 1) {
> if (val == 0 || val > MAX_TAG_SIZE) {
> ti->error = "Invalid integrity arguments";
> @@ -3218,10 +3345,36 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
> goto bad;
> }
>
> + 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 ||
> + tmpll != (sector_t)tmpll) {
> + ti->error = "Invalid device sector";
> + goto bad;
> + }
> + cc->start = tmpll;
> +
> ret = crypt_ctr_cipher(ti, argv[0], argv[1]);
> if (ret < 0)
> goto bad;
>
> + if (test_bit(DM_CRYPT_INLINE_ENCRYPTION, &cc->flags))
> + return 0;
> +
> if (crypt_integrity_aead(cc)) {
> cc->dmreq_start = sizeof(struct aead_request);
> cc->dmreq_start += crypto_aead_reqsize(any_tfm_aead(cc));
> @@ -3277,27 +3430,6 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
>
> 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 || tmpll != (sector_t)tmpll) {
> - ti->error = "Invalid device sector";
> - goto bad;
> - }
> - cc->start = tmpll;
> -
> if (bdev_is_zoned(cc->dev->bdev)) {
> /*
> * For zoned block devices, we need to preserve the issuer write
> @@ -3419,6 +3551,13 @@ static int crypt_map(struct dm_target *ti, struct bio *bio)
> if (unlikely(bio->bi_iter.bi_size & (cc->sector_size - 1)))
> return DM_MAPIO_KILL;
>
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> + if (test_bit(DM_CRYPT_INLINE_ENCRYPTION, &cc->flags)) {
> + crypt_inline_encrypt_submit(ti, bio);
> + return DM_MAPIO_SUBMITTED;
> + }
> +#endif
> +
> 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));
>
> @@ -3481,6 +3620,10 @@ static void crypt_status(struct dm_target *ti, status_type_t type,
> num_feature_args += test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags);
> num_feature_args += test_bit(DM_CRYPT_NO_READ_WORKQUEUE, &cc->flags);
> num_feature_args += test_bit(DM_CRYPT_NO_WRITE_WORKQUEUE, &cc->flags);
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> + num_feature_args +=
> + test_bit(DM_CRYPT_INLINE_ENCRYPTION, &cc->flags);
> +#endif
You do not think that you need the ifdef here. If CONFIG_BLK_INLINE_ENCRYPTION
is not enabled, then DM_CRYPT_INLINE_ENCRYPTION is never set.
> 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)
> @@ -3497,6 +3640,10 @@ static void crypt_status(struct dm_target *ti, status_type_t type,
> DMEMIT(" no_read_workqueue");
> if (test_bit(DM_CRYPT_NO_WRITE_WORKQUEUE, &cc->flags))
> DMEMIT(" no_write_workqueue");
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> + if (test_bit(DM_CRYPT_INLINE_ENCRYPTION, &cc->flags))
> + DMEMIT(" inline_crypt");
> +#endif
ditto.
> 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))
> @@ -3516,6 +3663,11 @@ static void crypt_status(struct dm_target *ti, status_type_t type,
> 'y' : 'n');
> DMEMIT(",no_write_workqueue=%c", test_bit(DM_CRYPT_NO_WRITE_WORKQUEUE, &cc->flags) ?
> 'y' : 'n');
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> + DMEMIT(",inline_crypt=%c",
> + test_bit(DM_CRYPT_INLINE_ENCRYPTION, &cc->flags) ?
> + 'y' : 'n');
> +#endif
You do not think that you need the ifdef here. If CONFIG_BLK_INLINE_ENCRYPTION
is not enabled, then inline_crypt=n will always be reported, which is fine I think.
> DMEMIT(",iv_large_sectors=%c", test_bit(CRYPT_IV_LARGE_SECTORS, &cc->cipher_flags) ?
> 'y' : 'n');
>
--
Damien Le Moal
Western Digital Research
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