Linux Virtualization - Jul 2019 - [PATCH v2 06/35] crypto: Use kmemdup rather than duplicating its implementation

kmemdup is introduced to duplicate a region of memory in a neat way.
Rather than kmalloc/kzalloc + memcpy, which the programmer needs to
write the size twice (sometimes lead to mistakes), kmemdup improves
readability, leads to smaller code and also reduce the chances of mistakes.
Suggestion to use kmemdup rather than using kmalloc/kzalloc + memcpy.

Signed-off-by: Fuqian Huang <huangfq.daxian at gmail.com>
---
Changes in v2:
  - Fix a typo in commit message (memset -> memcpy)

 drivers/crypto/caam/caampkc.c              | 11 +++--------
 drivers/crypto/virtio/virtio_crypto_algs.c |  4 +---
 2 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/drivers/crypto/caam/caampkc.c b/drivers/crypto/caam/caampkc.c
index fe24485274e1..a03464b4c019 100644
--- a/drivers/crypto/caam/caampkc.c
+++ b/drivers/crypto/caam/caampkc.c
@@ -816,7 +816,7 @@ static int caam_rsa_set_pub_key(struct crypto_akcipher *tfm,
const void *key,
 		return ret;
 
 	/* Copy key in DMA zone */
-	rsa_key->e = kzalloc(raw_key.e_sz, GFP_DMA | GFP_KERNEL);
+	rsa_key->e = kmemdup(raw_key.e, raw_key.e_sz, GFP_DMA | GFP_KERNEL);
 	if (!rsa_key->e)
 		goto err;
 
@@ -838,8 +838,6 @@ static int caam_rsa_set_pub_key(struct crypto_akcipher *tfm,
const void *key,
 	rsa_key->e_sz = raw_key.e_sz;
 	rsa_key->n_sz = raw_key.n_sz;
 
-	memcpy(rsa_key->e, raw_key.e, raw_key.e_sz);
-
 	return 0;
 err:
 	caam_rsa_free_key(rsa_key);
@@ -920,11 +918,11 @@ static int caam_rsa_set_priv_key(struct crypto_akcipher
*tfm, const void *key,
 		return ret;
 
 	/* Copy key in DMA zone */
-	rsa_key->d = kzalloc(raw_key.d_sz, GFP_DMA | GFP_KERNEL);
+	rsa_key->d = kmemdup(raw_key.d, raw_key.d_sz, GFP_DMA | GFP_KERNEL);
 	if (!rsa_key->d)
 		goto err;
 
-	rsa_key->e = kzalloc(raw_key.e_sz, GFP_DMA | GFP_KERNEL);
+	rsa_key->e = kmemdup(raw_key.e, raw_key.e_sz, GFP_DMA | GFP_KERNEL);
 	if (!rsa_key->e)
 		goto err;
 
@@ -947,9 +945,6 @@ static int caam_rsa_set_priv_key(struct crypto_akcipher
*tfm, const void *key,
 	rsa_key->e_sz = raw_key.e_sz;
 	rsa_key->n_sz = raw_key.n_sz;
 
-	memcpy(rsa_key->d, raw_key.d, raw_key.d_sz);
-	memcpy(rsa_key->e, raw_key.e, raw_key.e_sz);
-
 	caam_rsa_set_priv_key_form(ctx, &raw_key);
 
 	return 0;
diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c
b/drivers/crypto/virtio/virtio_crypto_algs.c
index 10f266d462d6..42d19205166b 100644
--- a/drivers/crypto/virtio/virtio_crypto_algs.c
+++ b/drivers/crypto/virtio/virtio_crypto_algs.c
@@ -129,13 +129,11 @@ static int virtio_crypto_alg_ablkcipher_init_session(
 	 * Avoid to do DMA from the stack, switch to using
 	 * dynamically-allocated for the key
 	 */
-	uint8_t *cipher_key = kmalloc(keylen, GFP_ATOMIC);
+	uint8_t *cipher_key = kmemdup(key, keylen, GFP_ATOMIC);
 
 	if (!cipher_key)
 		return -ENOMEM;
 
-	memcpy(cipher_key, key, keylen);
-
 	spin_lock(&vcrypto->ctrl_lock);
 	/* Pad ctrl header */
 	vcrypto->ctrl.header.opcode -- 
2.11.0

On 7/3/2019 7:27 PM, Fuqian Huang wrote:
> kmemdup is introduced to duplicate a region of memory in a neat way.
> Rather than kmalloc/kzalloc + memcpy, which the programmer needs to
> write the size twice (sometimes lead to mistakes), kmemdup improves
> readability, leads to smaller code and also reduce the chances of mistakes.
> Suggestion to use kmemdup rather than using kmalloc/kzalloc + memcpy.
> 
> Signed-off-by: Fuqian Huang <huangfq.daxian at gmail.com>
Reviewed-by: Horia Geant? <horia.geanta at nxp.com>

Thanks,
Horia

On Thu, Jul 04, 2019 at 12:27:08AM +0800, Fuqian Huang
wrote:
> kmemdup is introduced to duplicate a region of memory in a neat way.
> Rather than kmalloc/kzalloc + memcpy, which the programmer needs to
> write the size twice (sometimes lead to mistakes), kmemdup improves
> readability, leads to smaller code and also reduce the chances of mistakes.
> Suggestion to use kmemdup rather than using kmalloc/kzalloc + memcpy.
> 
> Signed-off-by: Fuqian Huang <huangfq.daxian at gmail.com>
virtio part:

Acked-by: Michael S. Tsirkin <mst at redhat.com>

> ---
> Changes in v2:
>   - Fix a typo in commit message (memset -> memcpy)
> 
>  drivers/crypto/caam/caampkc.c              | 11 +++--------
>  drivers/crypto/virtio/virtio_crypto_algs.c |  4 +---
>  2 files changed, 4 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/crypto/caam/caampkc.c b/drivers/crypto/caam/caampkc.c
> index fe24485274e1..a03464b4c019 100644
> --- a/drivers/crypto/caam/caampkc.c
> +++ b/drivers/crypto/caam/caampkc.c
> @@ -816,7 +816,7 @@ static int caam_rsa_set_pub_key(struct crypto_akcipher
*tfm, const void *key,
>  		return ret;
>  
>  	/* Copy key in DMA zone */
> -	rsa_key->e = kzalloc(raw_key.e_sz, GFP_DMA | GFP_KERNEL);
> +	rsa_key->e = kmemdup(raw_key.e, raw_key.e_sz, GFP_DMA | GFP_KERNEL);
>  	if (!rsa_key->e)
>  		goto err;
>  
> @@ -838,8 +838,6 @@ static int caam_rsa_set_pub_key(struct crypto_akcipher
*tfm, const void *key,
>  	rsa_key->e_sz = raw_key.e_sz;
>  	rsa_key->n_sz = raw_key.n_sz;
>  
> -	memcpy(rsa_key->e, raw_key.e, raw_key.e_sz);
> -
>  	return 0;
>  err:
>  	caam_rsa_free_key(rsa_key);
> @@ -920,11 +918,11 @@ static int caam_rsa_set_priv_key(struct
crypto_akcipher *tfm, const void *key,
>  		return ret;
>  
>  	/* Copy key in DMA zone */
> -	rsa_key->d = kzalloc(raw_key.d_sz, GFP_DMA | GFP_KERNEL);
> +	rsa_key->d = kmemdup(raw_key.d, raw_key.d_sz, GFP_DMA | GFP_KERNEL);
>  	if (!rsa_key->d)
>  		goto err;
>  
> -	rsa_key->e = kzalloc(raw_key.e_sz, GFP_DMA | GFP_KERNEL);
> +	rsa_key->e = kmemdup(raw_key.e, raw_key.e_sz, GFP_DMA | GFP_KERNEL);
>  	if (!rsa_key->e)
>  		goto err;
>  
> @@ -947,9 +945,6 @@ static int caam_rsa_set_priv_key(struct crypto_akcipher
*tfm, const void *key,
>  	rsa_key->e_sz = raw_key.e_sz;
>  	rsa_key->n_sz = raw_key.n_sz;
>  
> -	memcpy(rsa_key->d, raw_key.d, raw_key.d_sz);
> -	memcpy(rsa_key->e, raw_key.e, raw_key.e_sz);
> -
>  	caam_rsa_set_priv_key_form(ctx, &raw_key);
>  
>  	return 0;
> diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c
b/drivers/crypto/virtio/virtio_crypto_algs.c
> index 10f266d462d6..42d19205166b 100644
> --- a/drivers/crypto/virtio/virtio_crypto_algs.c
> +++ b/drivers/crypto/virtio/virtio_crypto_algs.c
> @@ -129,13 +129,11 @@ static int virtio_crypto_alg_ablkcipher_init_session(
>  	 * Avoid to do DMA from the stack, switch to using
>  	 * dynamically-allocated for the key
>  	 */
> -	uint8_t *cipher_key = kmalloc(keylen, GFP_ATOMIC);
> +	uint8_t *cipher_key = kmemdup(key, keylen, GFP_ATOMIC);
>  
>  	if (!cipher_key)
>  		return -ENOMEM;
>  
> -	memcpy(cipher_key, key, keylen);
> -
>  	spin_lock(&vcrypto->ctrl_lock);
>  	/* Pad ctrl header */
>  	vcrypto->ctrl.header.opcode > -- 
> 2.11.0

Fuqian Huang <huangfq.daxian at gmail.com> wrote:
> kmemdup is introduced to duplicate a region of memory in a neat way.
> Rather than kmalloc/kzalloc + memcpy, which the programmer needs to
> write the size twice (sometimes lead to mistakes), kmemdup improves
> readability, leads to smaller code and also reduce the chances of mistakes.
> Suggestion to use kmemdup rather than using kmalloc/kzalloc + memcpy.
> 
> Signed-off-by: Fuqian Huang <huangfq.daxian at gmail.com>
> ---
> Changes in v2:
>  - Fix a typo in commit message (memset -> memcpy)
> 
> drivers/crypto/caam/caampkc.c              | 11 +++--------
> drivers/crypto/virtio/virtio_crypto_algs.c |  4 +---
> 2 files changed, 4 insertions(+), 11 deletions(-)
Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert at gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt