Commit 070bb43a authored by Eric Biggers's avatar Eric Biggers Committed by Mike Snitzer
Browse files

dm integrity: use crypto_shash_digest() in sb_mac() 



Simplify sb_mac() by using crypto_shash_digest() instead of an
init+update+final sequence.  This should also improve performance.

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
parent 6d0ee3b6

drivers/md/dm-integrity.c

+10 −20
Original line number Diff line number Diff line
@@ -493,42 +493,32 @@ static int sb_mac(struct dm_integrity_c *ic, bool wr) 
{

	SHASH_DESC_ON_STACK(desc, ic->journal_mac);

	int r;

	unsigned int size = crypto_shash_digestsize(ic->journal_mac);

	unsigned int mac_size = crypto_shash_digestsize(ic->journal_mac);

	__u8 *sb = (__u8 *)ic->sb;

	__u8 *mac = sb + (1 << SECTOR_SHIFT) - mac_size;



	if (sizeof(struct superblock) + size > 1 << SECTOR_SHIFT) {

	if (sizeof(struct superblock) + mac_size > 1 << SECTOR_SHIFT) {

		dm_integrity_io_error(ic, "digest is too long", -EINVAL);

		return -EINVAL;

	}



	desc->tfm = ic->journal_mac;



	r = crypto_shash_init(desc);

	if (unlikely(r < 0)) {

		dm_integrity_io_error(ic, "crypto_shash_init", r);

		return r;

	}



	r = crypto_shash_update(desc, (__u8 *)ic->sb, (1 << SECTOR_SHIFT) - size);

	if (unlikely(r < 0)) {

		dm_integrity_io_error(ic, "crypto_shash_update", r);

		return r;

	}



	if (likely(wr)) {

		r = crypto_shash_final(desc, (__u8 *)ic->sb + (1 << SECTOR_SHIFT) - size);

		r = crypto_shash_digest(desc, sb, mac - sb, mac);

		if (unlikely(r < 0)) {

			dm_integrity_io_error(ic, "crypto_shash_final", r);

			dm_integrity_io_error(ic, "crypto_shash_digest", r);

			return r;

		}

	} else {

		__u8 result[HASH_MAX_DIGESTSIZE];

		__u8 actual_mac[HASH_MAX_DIGESTSIZE];



		r = crypto_shash_final(desc, result);

		r = crypto_shash_digest(desc, sb, mac - sb, actual_mac);

		if (unlikely(r < 0)) {

			dm_integrity_io_error(ic, "crypto_shash_final", r);

			dm_integrity_io_error(ic, "crypto_shash_digest", r);

			return r;

		}

		if (memcmp((__u8 *)ic->sb + (1 << SECTOR_SHIFT) - size, result, size)) {

		if (memcmp(mac, actual_mac, mac_size)) {

			dm_integrity_io_error(ic, "superblock mac", -EILSEQ);

			dm_audit_log_target(DM_MSG_PREFIX, "mac-superblock", ic->ti, 0);

			return -EILSEQ;