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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: Gilad Ben-Yossef <gilad@benyossef.com>
CC: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Gilad Ben-Yossef 2017-10-18 08:00:45 +01:00 committed by Herbert Xu
parent d0082e1a7c
commit 12f1ffc40a
2 changed files with 20 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

81
drivers/md/dm-verity-target.c
View File

@ -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;

5
drivers/md/dm-verity.h
View File

@ -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)
{