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Commit e74407ee authored by Eric Biggers's avatar Eric Biggers
Browse files

ANDROID: dm-default-key: set dun_bytes more precisely 



Make dm-default-key set dun_bytes to only what it actually needs, so
that it can make use of inline crypto hardware in more cases.

Bug: 144046242
Bug: 153512828
Change-Id: I338e6444e71be9c7c16ce70172d14a8e05301023
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
parent 5da8f890

drivers/md/dm-default-key.c

+16 −2
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ static const struct dm_default_key_cipher { 
 * @sector_size: crypto sector size in bytes (usually 4096)

 * @sector_bits: log2(sector_size)

 * @key: the encryption key to use

 * @max_dun: the maximum DUN that may be used (computed from other params)

 */

struct default_key_c {

	struct dm_dev *dev;
@@ -48,6 +49,7 @@ struct default_key_c { 
	unsigned int sector_bits;

	struct blk_crypto_key key;

	bool is_hw_wrapped;

	u64 max_dun;

};



static const struct dm_default_key_cipher *
@@ -147,6 +149,7 @@ static int default_key_ctr(struct dm_target *ti, unsigned int argc, char **argv) 
	const struct dm_default_key_cipher *cipher;

	u8 raw_key[DM_DEFAULT_KEY_MAX_WRAPPED_KEY_SIZE];

	unsigned int raw_key_size;

	unsigned int dun_bytes;

	unsigned long long tmpll;

	char dummy;

	int err;
@@ -230,15 +233,19 @@ static int default_key_ctr(struct dm_target *ti, unsigned int argc, char **argv) 
		goto bad;

	}



	dkc->max_dun = (dkc->iv_offset + ti->len - 1) >>

		       (dkc->sector_bits - SECTOR_SHIFT);

	dun_bytes = DIV_ROUND_UP(fls64(dkc->max_dun), 8);



	err = blk_crypto_init_key(&dkc->key, raw_key, raw_key_size,

				  dkc->is_hw_wrapped, cipher->mode_num,

				  sizeof(u64), dkc->sector_size);

				  dun_bytes, dkc->sector_size);

	if (err) {

		ti->error = "Error initializing blk-crypto key";

		goto bad;

	}



	err = blk_crypto_start_using_mode(cipher->mode_num, sizeof(u64),

	err = blk_crypto_start_using_mode(cipher->mode_num, dun_bytes,

					  dkc->sector_size, dkc->is_hw_wrapped,

					  dkc->dev->bdev->bd_queue);

	if (err) {
@@ -300,6 +307,13 @@ static int default_key_map(struct dm_target *ti, struct bio *bio) 
		return DM_MAPIO_KILL;

	dun[0] >>= dkc->sector_bits - SECTOR_SHIFT; /* crypto sectors */



	/*

	 * This check isn't necessary as we should have calculated max_dun

	 * correctly, but be safe.

	 */

	if (WARN_ON_ONCE(dun[0] > dkc->max_dun))

		return DM_MAPIO_KILL;



	bio_crypt_set_ctx(bio, &dkc->key, dun, GFP_NOIO);



	return DM_MAPIO_REMAPPED;