Commit 12f1ffc4 authored by Gilad Ben-Yossef's avatar Gilad Ben-Yossef Committed by Herbert Xu
Browse files

dm: move dm-verity to generic async completion 



dm-verity is starting async. crypto ops and waiting for them to complete.
Move it over to generic code doing the same.

This also avoids a future potential data coruption bug created
by the use of wait_for_completion_interruptible() without dealing
correctly with an interrupt aborting the wait prior to the
async op finishing, should this code ever move to a context
where signals are not masked.

Signed-off-by: default avatarGilad Ben-Yossef <gilad@benyossef.com>
CC: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent d0082e1a

drivers/md/dm-verity-target.c

+20 −61
Original line number Diff line number Diff line
@@ -92,74 +92,33 @@ static sector_t verity_position_at_level(struct dm_verity *v, sector_t block, 
	return block >> (level * v->hash_per_block_bits);

}



/*

 * Callback function for asynchrnous crypto API completion notification

 */

static void verity_op_done(struct crypto_async_request *base, int err)

{

	struct verity_result *res = (struct verity_result *)base->data;



	if (err == -EINPROGRESS)

		return;



	res->err = err;

	complete(&res->completion);

}



/*

 * Wait for async crypto API callback

 */

static inline int verity_complete_op(struct verity_result *res, int ret)

{

	switch (ret) {

	case 0:

		break;



	case -EINPROGRESS:

	case -EBUSY:

		ret = wait_for_completion_interruptible(&res->completion);

		if (!ret)

			ret = res->err;

		reinit_completion(&res->completion);

		break;



	default:

		DMERR("verity_wait_hash: crypto op submission failed: %d", ret);

	}



	if (unlikely(ret < 0))

		DMERR("verity_wait_hash: crypto op failed: %d", ret);



	return ret;

}



static int verity_hash_update(struct dm_verity *v, struct ahash_request *req,

				const u8 *data, size_t len,

				struct verity_result *res)

				struct crypto_wait *wait)

{

	struct scatterlist sg;



	sg_init_one(&sg, data, len);

	ahash_request_set_crypt(req, &sg, NULL, len);



	return verity_complete_op(res, crypto_ahash_update(req));

	return crypto_wait_req(crypto_ahash_update(req), wait);

}



/*

 * Wrapper for crypto_ahash_init, which handles verity salting.

 */

static int verity_hash_init(struct dm_verity *v, struct ahash_request *req,

				struct verity_result *res)

				struct crypto_wait *wait)

{

	int r;



	ahash_request_set_tfm(req, v->tfm);

	ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP |

					CRYPTO_TFM_REQ_MAY_BACKLOG,

					verity_op_done, (void *)res);

	init_completion(&res->completion);

					crypto_req_done, (void *)wait);

	crypto_init_wait(wait);



	r = verity_complete_op(res, crypto_ahash_init(req));

	r = crypto_wait_req(crypto_ahash_init(req), wait);



	if (unlikely(r < 0)) {

		DMERR("crypto_ahash_init failed: %d", r);
@@ -167,18 +126,18 @@ static int verity_hash_init(struct dm_verity *v, struct ahash_request *req, 
	}



	if (likely(v->salt_size && (v->version >= 1)))

		r = verity_hash_update(v, req, v->salt, v->salt_size, res);

		r = verity_hash_update(v, req, v->salt, v->salt_size, wait);



	return r;

}



static int verity_hash_final(struct dm_verity *v, struct ahash_request *req,

			     u8 *digest, struct verity_result *res)

			     u8 *digest, struct crypto_wait *wait)

{

	int r;



	if (unlikely(v->salt_size && (!v->version))) {

		r = verity_hash_update(v, req, v->salt, v->salt_size, res);

		r = verity_hash_update(v, req, v->salt, v->salt_size, wait);



		if (r < 0) {

			DMERR("verity_hash_final failed updating salt: %d", r);
@@ -187,7 +146,7 @@ static int verity_hash_final(struct dm_verity *v, struct ahash_request *req, 
	}



	ahash_request_set_crypt(req, NULL, digest, 0);

	r = verity_complete_op(res, crypto_ahash_final(req));

	r = crypto_wait_req(crypto_ahash_final(req), wait);

out:

	return r;

}
@@ -196,17 +155,17 @@ int verity_hash(struct dm_verity *v, struct ahash_request *req, 
		const u8 *data, size_t len, u8 *digest)

{

	int r;

	struct verity_result res;

	struct crypto_wait wait;



	r = verity_hash_init(v, req, &res);

	r = verity_hash_init(v, req, &wait);

	if (unlikely(r < 0))

		goto out;



	r = verity_hash_update(v, req, data, len, &res);

	r = verity_hash_update(v, req, data, len, &wait);

	if (unlikely(r < 0))

		goto out;



	r = verity_hash_final(v, req, digest, &res);

	r = verity_hash_final(v, req, digest, &wait);



out:

	return r;
@@ -389,7 +348,7 @@ out: 
 * Calculates the digest for the given bio

 */

int verity_for_io_block(struct dm_verity *v, struct dm_verity_io *io,

			struct bvec_iter *iter, struct verity_result *res)

			struct bvec_iter *iter, struct crypto_wait *wait)

{

	unsigned int todo = 1 << v->data_dev_block_bits;

	struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
@@ -414,7 +373,7 @@ int verity_for_io_block(struct dm_verity *v, struct dm_verity_io *io, 
		 */

		sg_set_page(&sg, bv.bv_page, len, bv.bv_offset);

		ahash_request_set_crypt(req, &sg, NULL, len);

		r = verity_complete_op(res, crypto_ahash_update(req));

		r = crypto_wait_req(crypto_ahash_update(req), wait);



		if (unlikely(r < 0)) {

			DMERR("verity_for_io_block crypto op failed: %d", r);
@@ -482,7 +441,7 @@ static int verity_verify_io(struct dm_verity_io *io) 
	struct dm_verity *v = io->v;

	struct bvec_iter start;

	unsigned b;

	struct verity_result res;

	struct crypto_wait wait;



	for (b = 0; b < io->n_blocks; b++) {

		int r;
@@ -507,17 +466,17 @@ static int verity_verify_io(struct dm_verity_io *io) 
			continue;

		}



		r = verity_hash_init(v, req, &res);

		r = verity_hash_init(v, req, &wait);

		if (unlikely(r < 0))

			return r;



		start = io->iter;

		r = verity_for_io_block(v, io, &io->iter, &res);

		r = verity_for_io_block(v, io, &io->iter, &wait);

		if (unlikely(r < 0))

			return r;



		r = verity_hash_final(v, req, verity_io_real_digest(v, io),

					&res);

					&wait);

		if (unlikely(r < 0))

			return r;

drivers/md/dm-verity.h

+0 −5
Original line number Diff line number Diff line
@@ -90,11 +90,6 @@ struct dm_verity_io { 
	 */

};



struct verity_result {

	struct completion completion;

	int err;

};



static inline struct ahash_request *verity_io_hash_req(struct dm_verity *v,

						     struct dm_verity_io *io)

{

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