[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 
---
 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

[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 
---
 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 v2 1/2] crypto: vmx - Use skcipher for cbc fallback

[Marcelo Cerri]

On Fri, Feb 24, 2017 at 11:23:54AM -0300, Paulo Flabiano Smorigo wrote:
> Signed-off-by: Paulo Flabiano Smorigo 
> ---
>  drivers/crypto/vmx/aes_cbc.c | 44 
> ++--
>  1 file changed, 22 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/crypto/vmx/aes_cbc.c b/drivers/crypto/vmx/aes_cbc.c
> index 94ad5c0..2bb5910 100644
> --- a/drivers/crypto/vmx/aes_cbc.c
> +++ b/drivers/crypto/vmx/aes_cbc.c
> @@ -27,11 +27,12 @@
>  #include 
>  #include 
>  #include 
> +#include 
>  
>  #include "aesp8-ppc.h"
>  
>  struct p8_aes_cbc_ctx {
> - struct crypto_blkcipher *fallback;
> + struct crypto_skcipher *fallback;
>   struct aes_key enc_key;
>   struct aes_key dec_key;
>  };
> @@ -39,7 +40,7 @@ struct p8_aes_cbc_ctx {
>  static int p8_aes_cbc_init(struct crypto_tfm *tfm)
>  {
>   const char *alg;
> - struct crypto_blkcipher *fallback;
> + struct crypto_skcipher *fallback;
>   struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
>  
>   if (!(alg = crypto_tfm_alg_name(tfm))) {
> @@ -47,8 +48,9 @@ static int p8_aes_cbc_init(struct crypto_tfm *tfm)
>   return -ENOENT;
>   }
>  
> - fallback =
> - crypto_alloc_blkcipher(alg, 0, CRYPTO_ALG_NEED_FALLBACK);
> + fallback = crypto_alloc_skcipher(alg, 0,
> + CRYPTO_ALG_ASYNC | CRYPTO_ALG_NEED_FALLBACK);
> +
>   if (IS_ERR(fallback)) {
>   printk(KERN_ERR
>  "Failed to allocate transformation for '%s': %ld\n",
> @@ -58,9 +60,9 @@ static int p8_aes_cbc_init(struct crypto_tfm *tfm)
>   printk(KERN_INFO "Using '%s' as fallback implementation.\n",
>  crypto_tfm_alg_driver_name((struct crypto_tfm *) fallback));

You need to update that to use crypto_skcipher_tfm(). The same is valid
for the xts patch.

>  
> - crypto_blkcipher_set_flags(
> + crypto_skcipher_set_flags(
>   fallback,
> - crypto_blkcipher_get_flags((struct crypto_blkcipher *)tfm));
> + crypto_skcipher_get_flags((struct crypto_skcipher *)tfm));
>   ctx->fallback = fallback;
>  
>   return 0;
> @@ -71,7 +73,7 @@ static void p8_aes_cbc_exit(struct crypto_tfm *tfm)
>   struct p8_aes_cbc_ctx *ctx = crypto_tfm_ctx(tfm);
>  
>   if (ctx->fallback) {
> - crypto_free_blkcipher(ctx->fallback);
> + crypto_free_skcipher(ctx->fallback);
>   ctx->fallback = NULL;
>   }
>  }
> @@ -91,7 +93,7 @@ static int p8_aes_cbc_setkey(struct crypto_tfm *tfm, const 
> u8 *key,
>   pagefault_enable();
>   preempt_enable();
>  
> - ret += crypto_blkcipher_setkey(ctx->fallback, key, keylen);
> + ret += crypto_skcipher_setkey(ctx->fallback, key, keylen);
>   return ret;
>  }
>  
> @@ -103,15 +105,14 @@ static int p8_aes_cbc_encrypt(struct blkcipher_desc 
> *desc,
>   struct blkcipher_walk walk;
>   struct p8_aes_cbc_ctx *ctx =
>   crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
> - struct blkcipher_desc fallback_desc = {
> - .tfm = ctx->fallback,
> - .info = desc->info,
> - .flags = desc->flags
> - };
>  
>   if (in_interrupt()) {
> - ret = crypto_blkcipher_encrypt(_desc, dst, src,
> -nbytes);
> + SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback);
> + skcipher_request_set_tfm(req, ctx->fallback);
> + skcipher_request_set_callback(req, desc->flags, NULL, NULL);
> + skcipher_request_set_crypt(req, src, dst, nbytes, desc->info);
> + ret = crypto_skcipher_encrypt(req);
> + skcipher_request_zero(req);
>   } else {
>   preempt_disable();
>   pagefault_disable();
> @@ -144,15 +145,14 @@ static int p8_aes_cbc_decrypt(struct blkcipher_desc 
> *desc,
>   struct blkcipher_walk walk;
>   struct p8_aes_cbc_ctx *ctx =
>   crypto_tfm_ctx(crypto_blkcipher_tfm(desc->tfm));
> - struct blkcipher_desc fallback_desc = {
> - .tfm = ctx->fallback,
> - .info = desc->info,
> - .flags = desc->flags
> - };
>  
>   if (in_interrupt()) {
> - ret = crypto_blkcipher_decrypt(_desc, dst, src,
> -nbytes);
> + SKCIPHER_REQUEST_ON_STACK(req, ctx->fallback);
> + skcipher_request_set_tfm(req, ctx->fallback);
> + skcipher_request_set_callback(req, desc->flags, NULL, NULL);
> + skcipher_request_set_crypt(req, src, dst, nbytes, desc->info);
> + ret = crypto_skcipher_decrypt(req);
> + skcipher_request_zero(req);
>   } else {
>   preempt_disable();
>   pagefault_disable();
> -- 
> 2.7.4
> 

-- 
Regards,
Marcelo



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Re: crypto: hang in crypto_larval_lookup

[Harald Freudenberger]

On 02/26/2017 05:22 AM, Herbert Xu wrote:
> On Sat, Feb 25, 2017 at 04:20:22PM -0300, Marcelo Cerri wrote:
>> Yeah, I agree. This should work as long as the module aliases are
>> correct, which is enough.
>>
>> Other templates will not trigger the same error since they don't have to
>> try more than one underlying algorithm. But I think this is still
>> desirable for the remaining templates to avoid a long chain of unused
>> fallbacks as in the example I gave in my previous email.
>>
>> Probably a helper function to return the correct mask might be useful
>> for readability and to avoid duplicate code.
> You're right.  Here is a patch to add a helper for this.
> Thanks!
>
> ---8<---
> Subject: crypto: api - Add crypto_requires_off helper
>
> This patch adds crypto_requires_off which is an extension of
> crypto_requires_sync for similar bits such as NEED_FALLBACK.
>
> Suggested-by: Marcelo Cerri 
> Signed-off-by: Herbert Xu 
>
> diff --git a/include/crypto/algapi.h b/include/crypto/algapi.h
> index ebe4ded..436c4c2 100644
> --- a/include/crypto/algapi.h
> +++ b/include/crypto/algapi.h
> @@ -360,13 +360,18 @@ static inline struct crypto_alg 
> *crypto_get_attr_alg(struct rtattr **tb,
>   return crypto_attr_alg(tb[1], type, mask);
>  }
>
> +static inline int crypto_requires_off(u32 type, u32 mask, u32 off)
> +{
> + return (type ^ off) & mask & off;
> +}
> +
>  /*
>   * Returns CRYPTO_ALG_ASYNC if type/mask requires the use of sync algorithms.
>   * Otherwise returns zero.
>   */
>  static inline int crypto_requires_sync(u32 type, u32 mask)
>  {
> - return (type ^ CRYPTO_ALG_ASYNC) & mask & CRYPTO_ALG_ASYNC;
> + return crypto_requires_off(type, mask, CRYPTO_ALG_ASYNC);
>  }
>
>  noinline unsigned long __crypto_memneq(const void *a, const void *b, size_t 
> size);
applied the xts.c create patch v2 and the helper patch, built and installed.
Now the aes_s390 module loads perfect without any hang, no complains
in syslog and /proc/crypto shows that all selftests for the algs in the module
passed successful.

Thanks all for your help :-)

regards, Harald Freudenberger