[PATCH 0/2] Propagate fallback bit for cbc and ctr

[PATCH 0/2] Propagate fallback bit for cbc and ctr

[Marcelo Henrique Cerri]

Hi Herbert,

These are similar changes for cbc and ctr as the one you did for xts. They
rely on the helper function you created.

I confirmed that for vmx-crypto those changes cause the driver to allocate
"cbc(aes-generic)" and "ctr(aes-generic)" as fallbacks instead of
"cbc(p8_aes)" and "ctr(p8_aes)".

If you are ok with those changes, I can convert the remaining templates.

Marcelo Henrique Cerri (2):
  crypto: cbc - Propagate NEED_FALLBACK bit
  crypto: ctr - Propagate NEED_FALLBACK bit

 crypto/cbc.c | 20 ++++++++++++++------
 crypto/ctr.c | 13 +++++++++++--
 2 files changed, 25 insertions(+), 8 deletions(-)

-- 
2.7.4

[PATCH 1/2] crypto: cbc - Propagate NEED_FALLBACK bit

[Marcelo Henrique Cerri]

When requesting a fallback algorithm, we should propagate the
NEED_FALLBACK bit when search for the underlying algorithm.

This will prevents drivers from allocating unnecessary fallbacks that
are never called. For instance, currently the vmx-crypto driver will use
the following chain of calls when calling the fallback implementation:

p8_aes_cbc -> cbc(p8_aes) -> aes-generic

However p8_aes will always delegate its calls to aes-generic. With this
patch, p8_aes_cbc will be able to use cbc(aes-generic) directly as its
fallback. The same applies to aes_s390.

Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
---
 crypto/cbc.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/crypto/cbc.c b/crypto/cbc.c
index bc160a3..7147842 100644
--- a/crypto/cbc.c
+++ b/crypto/cbc.c
@@ -108,24 +108,32 @@ static void crypto_cbc_free(struct skcipher_instance *inst)
 static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
 {
 	struct skcipher_instance *inst;
+	struct crypto_attr_type *algt;
 	struct crypto_spawn *spawn;
 	struct crypto_alg *alg;
+	u32 mask;
 	int err;
 
 	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER);
 	if (err)
 		return err;
 
+	algt = crypto_get_attr_type(tb);
+	if (IS_ERR(algt))
+		return PTR_ERR(algt);
+
+	mask = CRYPTO_ALG_TYPE_MASK |
+		crypto_requires_off(algt->type, algt->mask,
+				    CRYPTO_ALG_NEED_FALLBACK);
+
+	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, mask);
+	if (IS_ERR(alg))
+		return PTR_ERR(alg);
+
 	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
 	if (!inst)
 		return -ENOMEM;
 
-	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
-				  CRYPTO_ALG_TYPE_MASK);
-	err = PTR_ERR(alg);
-	if (IS_ERR(alg))
-		goto err_free_inst;
-
 	spawn = skcipher_instance_ctx(inst);
 	err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
 				CRYPTO_ALG_TYPE_MASK);
-- 
2.7.4

Re: [PATCH 1/2] crypto: cbc - Propagate NEED_FALLBACK bit

[Herbert Xu]

On Sun, Feb 26, 2017 at 10:03:18PM -0300, Marcelo Henrique Cerri wrote:
> When requesting a fallback algorithm, we should propagate the
> NEED_FALLBACK bit when search for the underlying algorithm.
> 
> This will prevents drivers from allocating unnecessary fallbacks that
> are never called. For instance, currently the vmx-crypto driver will use
> the following chain of calls when calling the fallback implementation:
> 
> p8_aes_cbc -> cbc(p8_aes) -> aes-generic
> 
> However p8_aes will always delegate its calls to aes-generic. With this
> patch, p8_aes_cbc will be able to use cbc(aes-generic) directly as its
> fallback. The same applies to aes_s390.
> 
> Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
> ---
>  crypto/cbc.c | 20 ++++++++++++++------
>  1 file changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/crypto/cbc.c b/crypto/cbc.c
> index bc160a3..7147842 100644
> --- a/crypto/cbc.c
> +++ b/crypto/cbc.c
> @@ -108,24 +108,32 @@ static void crypto_cbc_free(struct skcipher_instance *inst)
>  static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
>  {
>  	struct skcipher_instance *inst;
> +	struct crypto_attr_type *algt;
>  	struct crypto_spawn *spawn;
>  	struct crypto_alg *alg;
> +	u32 mask;
>  	int err;
>  
>  	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER);
>  	if (err)
>  		return err;
>  
> +	algt = crypto_get_attr_type(tb);
> +	if (IS_ERR(algt))
> +		return PTR_ERR(algt);
> +
> +	mask = CRYPTO_ALG_TYPE_MASK |
> +		crypto_requires_off(algt->type, algt->mask,
> +				    CRYPTO_ALG_NEED_FALLBACK);
> +
> +	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, mask);
> +	if (IS_ERR(alg))
> +		return PTR_ERR(alg);
> +
>  	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
>  	if (!inst)
>  		return -ENOMEM;

You're leaking alg if the kzalloc of inst fails.  Easiest fix
would be to do crypto_get_attr_alg after the kzalloc as is the
status quo.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

[PATCH 2/2] crypto: ctr - Propagate NEED_FALLBACK bit

[Marcelo Henrique Cerri]

When requesting a fallback algorithm, we should propagate the
NEED_FALLBACK bit when search for the underlying algorithm.

This will prevents drivers from allocating unnecessary fallbacks that
are never called. For instance, currently the vmx-crypto driver will use
the following chain of calls when calling the fallback implementation:

p8_aes_ctr -> ctr(p8_aes) -> aes-generic

However p8_aes will always delegate its calls to aes-generic. With this
patch, p8_aes_ctr will be able to use ctr(aes-generic) directly as its
fallback. The same applies to aes_s390.

Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
---
 crypto/ctr.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/crypto/ctr.c b/crypto/ctr.c
index a4f4a89..3afe21a 100644
--- a/crypto/ctr.c
+++ b/crypto/ctr.c
@@ -181,15 +181,24 @@ static void crypto_ctr_exit_tfm(struct crypto_tfm *tfm)
 static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb)
 {
 	struct crypto_instance *inst;
+	struct crypto_attr_type *algt;
 	struct crypto_alg *alg;
+	u32 mask;
 	int err;
 
 	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
 	if (err)
 		return ERR_PTR(err);
 
-	alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
-				  CRYPTO_ALG_TYPE_MASK);
+	algt = crypto_get_attr_type(tb);
+	if (IS_ERR(algt))
+		return PTR_ERR(algt);
+
+	mask = CRYPTO_ALG_TYPE_MASK |
+		crypto_requires_off(algt->type, algt->mask,
+				    CRYPTO_ALG_NEED_FALLBACK);
+
+	alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER, mask);
 	if (IS_ERR(alg))
 		return ERR_CAST(alg);
 
-- 
2.7.4