Re: [PATCH] crypto: using size_add() for kmalloc()

[Su Hui <suhui@nfschina.com>]

On 2025/4/21 13:51, Su Hui wrote:
> It's safer to use size_add() to replace open-coded aithmetic in allocator
> arguments, because size_add() can prevent possible overflow problem.
>
> Signed-off-by: Su Hui <suhui@nfschina.com>
> ---
>   include/crypto/aead.h     | 3 ++-
>   include/crypto/akcipher.h | 4 +++-
>   include/crypto/kpp.h      | 3 ++-
>   3 files changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/include/crypto/aead.h b/include/crypto/aead.h
> index 0e8a41638678..cf212d28fe18 100644
> --- a/include/crypto/aead.h
> +++ b/include/crypto/aead.h
> @@ -10,6 +10,7 @@
>   
>   #include <linux/atomic.h>
>   #include <linux/container_of.h>
> +#include <linux/overflow.h>
Sorry for this redundant <linux/overflow.h>, will remove in v2 patch.
>   #include <linux/crypto.h>
>   #include <linux/slab.h>
>   #include <linux/types.h>
> @@ -433,7 +434,7 @@ static inline struct aead_request *aead_request_alloc(struct crypto_aead *tfm,
>   {
>   	struct aead_request *req;
>   
> -	req = kmalloc(sizeof(*req) + crypto_aead_reqsize(tfm), gfp);
> +	req = kmalloc(size_add(sizeof(*req), crypto_aead_reqsize(tfm)), gfp);
>   
>   	if (likely(req))
>   		aead_request_set_tfm(req, tfm);
> diff --git a/include/crypto/akcipher.h b/include/crypto/akcipher.h
> index cdf7da74bf2f..4c37a602cce5 100644
> --- a/include/crypto/akcipher.h
> +++ b/include/crypto/akcipher.h
> @@ -10,6 +10,7 @@
>   
>   #include <linux/atomic.h>
>   #include <linux/crypto.h>
> +#include <linux/overflow.h>
>   
>   /**
>    * struct akcipher_request - public key cipher request
> @@ -184,7 +185,8 @@ static inline struct akcipher_request *akcipher_request_alloc(
>   {
>   	struct akcipher_request *req;
>   
> -	req = kmalloc(sizeof(*req) + crypto_akcipher_reqsize(tfm), gfp);
> +	req = kmalloc(size_add(sizeof(*req),
> +			       crypto_akcipher_reqsize(tfm)), gfp);
>   	if (likely(req))
>   		akcipher_request_set_tfm(req, tfm);
>   
> diff --git a/include/crypto/kpp.h b/include/crypto/kpp.h
> index 2d9c4de57b69..11ae1ad41d2a 100644
> --- a/include/crypto/kpp.h
> +++ b/include/crypto/kpp.h
> @@ -11,6 +11,7 @@
>   
>   #include <linux/atomic.h>
>   #include <linux/container_of.h>
> +#include <linux/overflow.h>
>   #include <linux/crypto.h>
>   #include <linux/slab.h>
>   
> @@ -182,7 +183,7 @@ static inline struct kpp_request *kpp_request_alloc(struct crypto_kpp *tfm,
>   {
>   	struct kpp_request *req;
>   
> -	req = kmalloc(sizeof(*req) + crypto_kpp_reqsize(tfm), gfp);
> +	req = kmalloc(size_add(sizeof(*req), crypto_kpp_reqsize(tfm)), gfp);
>   	if (likely(req))
>   		kpp_request_set_tfm(req, tfm);
>