linux-kernel - Re: [PATCH] keys: Replace memcpy with strscpy in proc_keys

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Message-ID: <aR0tME7U4tYNH-x6@kernel.org>
Date: Wed, 19 Nov 2025 04:36:32 +0200
From: Jarkko Sakkinen <jarkko@...nel.org>
To: Thorsten Blum <thorsten.blum@...ux.dev>
Cc: David Howells <dhowells@...hat.com>, Paul Moore <paul@...l-moore.com>,
	James Morris <jmorris@...ei.org>,
	"Serge E. Hallyn" <serge@...lyn.com>, keyrings@...r.kernel.org,
	linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] keys: Replace memcpy with strscpy in proc_keys_show

On Wed, Nov 12, 2025 at 06:26:21PM +0100, Thorsten Blum wrote:
> Use strscpy() to copy strings into the fixed-size buffer 'xbuf' instead
> of hardcoding the number of bytes to copy. This improves maintainability

I don't consider maintainaibility as a stimulus of applying change given
that as a word it means me absolutely nothing.

> and ensures the buffer is always NUL-terminated.
> 
> Signed-off-by: Thorsten Blum <thorsten.blum@...ux.dev>
> ---
>  security/keys/proc.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/security/keys/proc.c b/security/keys/proc.c
> index 4f4e2c1824f1..1d380766f45d 100644
> --- a/security/keys/proc.c
> +++ b/security/keys/proc.c
> @@ -10,6 +10,7 @@
>  #include <linux/fs.h>
>  #include <linux/proc_fs.h>
>  #include <linux/seq_file.h>
> +#include <linux/string.h>
>  #include <asm/errno.h>
>  #include "internal.h"
>  
> @@ -199,9 +200,9 @@ static int proc_keys_show(struct seq_file *m, void *v)
>  	/* come up with a suitable timeout value */
>  	expiry = READ_ONCE(key->expiry);
>  	if (expiry == TIME64_MAX) {
> -		memcpy(xbuf, "perm", 5);
> +		strscpy(xbuf, "perm");
>  	} else if (now >= expiry) {
> -		memcpy(xbuf, "expd", 5);
> +		strscpy(xbuf, "expd");
>  	} else {
>  		timo = expiry - now;
>  
> -- 
> 2.51.0
> 

BR, Jarkko