Use kmalloc_flex() when allocating a new 'struct user_key_payload' in
user_preparse() to replace the open-coded size arithmetic and to keep
the size type-safe.

Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
 security/keys/user_defined.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
index 686d56e4cc85..6f88b507f927 100644
--- a/security/keys/user_defined.c
+++ b/security/keys/user_defined.c
@@ -64,7 +64,7 @@ int user_preparse(struct key_preparsed_payload *prep)
 	if (datalen == 0 || datalen > 32767 || !prep->data)
 		return -EINVAL;
 
-	upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
+	upayload = kmalloc_flex(*upayload, data, datalen);
 	if (!upayload)
 		return -ENOMEM;
 
-- 
Thorsten Blum <thorsten.blum@linux.dev>
GPG: 1D60 735E 8AEF 3BE4 73B6  9D84 7336 78FD 8DFE EAD4

On Mon, Mar 02, 2026 at 12:13:11PM +0100, Thorsten Blum wrote:
> Use kmalloc_flex() when allocating a new 'struct user_key_payload' in
> user_preparse() to replace the open-coded size arithmetic and to keep
> the size type-safe.
> 
> Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
> ---
>  security/keys/user_defined.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/security/keys/user_defined.c b/security/keys/user_defined.c
> index 686d56e4cc85..6f88b507f927 100644
> --- a/security/keys/user_defined.c
> +++ b/security/keys/user_defined.c
> @@ -64,7 +64,7 @@ int user_preparse(struct key_preparsed_payload *prep)
>  	if (datalen == 0 || datalen > 32767 || !prep->data)
>  		return -EINVAL;
>  
> -	upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
> +	upayload = kmalloc_flex(*upayload, data, datalen);
>  	if (!upayload)
>  		return -ENOMEM;
>  
> -- 
> Thorsten Blum <thorsten.blum@linux.dev>
> GPG: 1D60 735E 8AEF 3BE4 73B6  9D84 7336 78FD 8DFE EAD4
> 

David, do we want this?

BR, Jarkko