linux-kernel - Re: [PATCH v2] params: Replace deprecated strcpy() with strscpy() and memcpy()

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Message-ID: <f60327bb-6546-4d15-8bd2-a05e85d96b4f@suse.com>
Date: Wed, 13 Aug 2025 16:14:41 +0200
From: Petr Pavlu <petr.pavlu@...e.com>
To: Thorsten Blum <thorsten.blum@...ux.dev>
Cc: Thomas Weißschuh <linux@...ssschuh.net>,
 Shyam Saini <shyamsaini@...ux.microsoft.com>,
 Luis Chamberlain <mcgrof@...nel.org>, Dmitry Antipov <dmantipov@...dex.ru>,
 linux-kernel@...r.kernel.org, linux-modules@...r.kernel.org,
 Daniel Gomez <da.gomez@...nel.org>
Subject: Re: [PATCH v2] params: Replace deprecated strcpy() with strscpy() and
 memcpy()

On 8/13/25 3:21 PM, Thorsten Blum wrote:
> strcpy() is deprecated; use strscpy() and memcpy() instead.
> 
> In param_set_copystring(), we can safely use memcpy() because we already
> know the length of the source string 'val' and that it is guaranteed to
> be NUL-terminated within the first 'kps->maxlen' bytes.
> 
> Link: https://github.com/KSPP/linux/issues/88
> Signed-off-by: Thorsten Blum <thorsten.blum@...ux.dev>
> ---
> Changes in v2:
> - Use memcpy() in param_set_copystring() as suggested by Petr Pavlu
> - Link to v1: https://lore.kernel.org/lkml/20250810214456.2236-1-thorsten.blum@linux.dev/
> ---
>  kernel/params.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/kernel/params.c b/kernel/params.c
> index b92d64161b75..b96cfd693c99 100644
> --- a/kernel/params.c
> +++ b/kernel/params.c
> @@ -513,13 +513,14 @@ EXPORT_SYMBOL(param_array_ops);
>  int param_set_copystring(const char *val, const struct kernel_param *kp)
>  {
>  	const struct kparam_string *kps = kp->str;
> +	const size_t len = strnlen(val, kps->maxlen);
>  
> -	if (strnlen(val, kps->maxlen) == kps->maxlen) {
> +	if (len == kps->maxlen) {
>  		pr_err("%s: string doesn't fit in %u chars.\n",
>  		       kp->name, kps->maxlen-1);
>  		return -ENOSPC;
>  	}
> -	strcpy(kps->string, val);
> +	memcpy(kps->string, val, len + 1);
>  	return 0;
>  }
>  EXPORT_SYMBOL(param_set_copystring);
> @@ -841,7 +842,7 @@ static void __init param_sysfs_builtin(void)
>  		dot = strchr(kp->name, '.');
>  		if (!dot) {
>  			/* This happens for core_param() */
> -			strcpy(modname, "kernel");
> +			strscpy(modname, "kernel");
>  			name_len = 0;
>  		} else {
>  			name_len = dot - kp->name + 1;

Reviewed-by: Petr Pavlu <petr.pavlu@...e.com>

-- 
Thanks,
Petr