linux-kernel - Re: [PATCH 1/2] binfmt: Use struct

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Message-ID: <871qj0l8ln.fsf@email.froward.int.ebiederm.org>
Date:   Sun, 28 May 2023 11:32:52 -0500
From:   "Eric W. Biederman" <ebiederm@...ssion.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc:     Alexander Viro <viro@...iv.linux.org.uk>,
        Christian Brauner <brauner@...nel.org>,
        Kees Cook <keescook@...omium.org>,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH 1/2] binfmt: Use struct_size()

Christophe JAILLET <christophe.jaillet@...adoo.fr> writes:

> Use struct_size() instead of hand-writing it. It is less verbose, more
> robust and more informative.

Acked-by: "Eric W. Biederman" <ebiederm@...ssion.com>
Obviously correct transform.

>
> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> ---
> Compile tested on arm
> ---
>  fs/binfmt_elf_fdpic.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
> index d76ad3d4f676..237ce388d06d 100644
> --- a/fs/binfmt_elf_fdpic.c
> +++ b/fs/binfmt_elf_fdpic.c
> @@ -748,7 +748,6 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params,
>  	struct elf32_phdr *phdr;
>  	unsigned long load_addr, stop;
>  	unsigned nloads, tmp;
> -	size_t size;
>  	int loop, ret;
>  
>  	/* allocate a load map table */
> @@ -760,8 +759,7 @@ static int elf_fdpic_map_file(struct elf_fdpic_params *params,
>  	if (nloads == 0)
>  		return -ELIBBAD;
>  
> -	size = sizeof(*loadmap) + nloads * sizeof(*seg);
> -	loadmap = kzalloc(size, GFP_KERNEL);
> +	loadmap = kzalloc(struct_size(loadmap, segs, nloads), GFP_KERNEL);
>  	if (!loadmap)
>  		return -ENOMEM;