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

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Message-ID: <b047f0b3-303b-48f2-bce0-5b8d825f97e1@kernel.org>
Date: Fri, 15 Aug 2025 21:19:48 +0200
From: Daniel Gomez <da.gomez@...nel.org>
To: Petr Pavlu <petr.pavlu@...e.com>, 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,
 Kees Cook <kees@...nel.org>
Subject: Re: [PATCH v2] params: Replace deprecated strcpy() with strscpy() and
 memcpy()

On 13/08/2025 07.14, Petr Pavlu wrote:
> 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>
> 

Reviewed-by: Daniel Gomez <da.gomez@...sung.com>