Re: [dm-devel] [PATCH 2/4] crypto: pass the flag CRYPTO_ALG_ALLOCATES_MEMORY

Eric Biggers
2020-06-16T17:42:45Z

On Tue, Jun 16, 2020 at 11:01:58AM -0400, Mikulas Patocka wrote:
> Pass the flag CRYPTO_ALG_ALLOCATES_MEMORY down through the crypto API.
>
> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
>
> ---
> crypto/adiantum.c | 3 ++-
> crypto/authenc.c | 5 +++--
> crypto/authencesn.c | 5 +++--
> crypto/ccm.c | 7 ++++---
> crypto/chacha20poly1305.c | 5 +++--
> crypto/cryptd.c | 7 +++++--
> crypto/ctr.c | 3 ++-
> crypto/cts.c | 5 +++--
> crypto/essiv.c | 5 +++--
> crypto/gcm.c | 15 +++++++++------
> crypto/geniv.c | 3 ++-
> crypto/lrw.c | 5 +++--
> crypto/rsa-pkcs1pad.c | 5 +++--
> crypto/xts.c | 2 +-
> include/crypto/algapi.h | 9 +++++++++
> 15 files changed, 55 insertions(+), 29 deletions(-)
>
> Index: linux-2.6/crypto/authenc.c
> ===================================================================
> --- linux-2.6.orig/crypto/authenc.c
> +++ linux-2.6/crypto/authenc.c
> @@ -388,7 +388,8 @@ static int crypto_authenc_create(struct
> if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
> return -EINVAL;
>
> - mask = crypto_requires_sync(algt->type, algt->mask);
> + mask = crypto_requires_sync(algt->type, algt->mask) |
> + crypto_requires_nomem(algt->type, algt->mask);
>
> inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
> if (!inst)
> @@ -424,7 +425,7 @@ static int crypto_authenc_create(struct
> goto err_free_inst;
>
> inst->alg.base.cra_flags = (auth_base->cra_flags |
> - enc->base.cra_flags) & CRYPTO_ALG_ASYNC;
> + enc->base.cra_flags) & (CRYPTO_ALG_ASYNC | CRYPTO_ALG_ALLOCATES_MEMORY);

ASYNC and ALLOCATES_MEMORY are both handled the same way. They're both
"inherited" from inner algorithms to the template instance. And if someone
requests that one of these flags be clear when instantiating a template, then we
have to honor the same for the inner algorithms too.

So, shouldn't we define something like crypto_algt_mask() and
CRYPTO_ALG_INHERITED_FLAGS and make them handle both ASYNC and ALLOCATES_MEMORY,
rather than explicitly handling each of these flags everywhere again?

- Eric