crypto: shash - remove shash_desc::flags

The flags field in 'struct shash_desc' never actually does anything.
The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP.
However, no shash algorithm ever sleeps, making this flag a no-op.

With this being the case, inevitably some users who can't sleep wrongly
pass MAY_SLEEP.  These would all need to be fixed if any shash algorithm
actually started sleeping.  For example, the shash_ahash_*() functions,
which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP
from the ahash API to the shash API.  However, the shash functions are
called under kmap_atomic(), so actually they're assumed to never sleep.

Even if it turns out that some users do need preemption points while
hashing large buffers, we could easily provide a helper function
crypto_shash_update_large() which divides the data into smaller chunks
and calls crypto_shash_update() and cond_resched() for each chunk.  It's
not necessary to have a flag in 'struct shash_desc', nor is it necessary
to make individual shash algorithms aware of this at all.

Therefore, remove shash_desc::flags, and document that the
crypto_shash_*() functions can be called from any context.

Signed-off-by: Eric Biggers <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>
This commit is contained in:
Eric Biggers 2019-04-14 17:37:09 -07:00 • committed by Herbert Xu
commit 877b5691f2
66 changed files with 8 additions and 113 deletions

View file

@ -43,7 +43,6 @@ char *aa_calc_hash(void *data, size_t len)
goto fail;
desc->tfm = apparmor_tfm;
desc->flags = 0;
error = crypto_shash_init(desc);
if (error)
@ -81,7 +80,6 @@ int aa_calc_profile_hash(struct aa_profile *profile, u32 version, void *start,
goto fail;
desc->tfm = apparmor_tfm;
desc->flags = 0;
error = crypto_shash_init(desc);
if (error)

View file

@ -124,7 +124,6 @@ out:
return ERR_PTR(-ENOMEM);
desc->tfm = *tfm;
desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
rc = crypto_shash_init(desc);
if (rc) {

View file

@ -333,7 +333,6 @@ static int ima_calc_file_hash_tfm(struct file *file,
SHASH_DESC_ON_STACK(shash, tfm);
shash->tfm = tfm;
shash->flags = 0;
hash->length = crypto_shash_digestsize(tfm);
@ -469,7 +468,6 @@ static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
int rc, i;
shash->tfm = tfm;
shash->flags = 0;
hash->length = crypto_shash_digestsize(tfm);
@ -591,7 +589,6 @@ static int calc_buffer_shash_tfm(const void *buf, loff_t size,
int rc;
shash->tfm = tfm;
shash->flags = 0;
hash->length = crypto_shash_digestsize(tfm);
@ -664,7 +661,6 @@ static int __init ima_calc_boot_aggregate_tfm(char *digest,
SHASH_DESC_ON_STACK(shash, tfm);
shash->tfm = tfm;
shash->flags = 0;
rc = crypto_shash_init(shash);
if (rc != 0)

View file

@ -112,7 +112,6 @@ static int kdf_alloc(struct kdf_sdesc **sdesc_ret, char *hashname)
if (!sdesc)
goto out_free_tfm;
sdesc->shash.tfm = tfm;
sdesc->shash.flags = 0x0;
*sdesc_ret = sdesc;

View file

@ -333,7 +333,6 @@ static int calc_hash(struct crypto_shash *tfm, u8 *digest,
int err;
desc->tfm = tfm;
desc->flags = 0;
err = crypto_shash_digest(desc, buf, buflen, digest);
shash_desc_zero(desc);

View file

@ -55,7 +55,6 @@ static struct sdesc *init_sdesc(struct crypto_shash *alg)
if (!sdesc)
return ERR_PTR(-ENOMEM);
sdesc->shash.tfm = alg;
sdesc->shash.flags = 0x0;
return sdesc;
}