linux-kernel - Re: [PATCH] comedi: Replace kcalloc + copy_from_user with memdup_array

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <19be6d8a-e923-49ab-93e4-0996b7d3ddf2@mev.co.uk>
Date: Wed, 17 Sep 2025 14:41:48 +0100
From: Ian Abbott <abbotti@....co.uk>
To: Thorsten Blum <thorsten.blum@...ux.dev>,
 H Hartley Sweeten <hsweeten@...ionengravers.com>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Jann Horn
 <jannh@...gle.com>, Jens Axboe <axboe@...nel.dk>
Cc: linux-kernel@...r.kernel.org
Subject: Re: [PATCH] comedi: Replace kcalloc + copy_from_user with
 memdup_array_user

On 17/09/2025 14:13, Thorsten Blum wrote:
> Replace kcalloc() followed by copy_from_user() with memdup_array_user()
> to improve and simplify comedi_unlocked_ioctl().
> 
> No functional changes intended.
> 
> Signed-off-by: Thorsten Blum <thorsten.blum@...ux.dev>
> ---
>   drivers/comedi/comedi_fops.c | 13 ++++---------
>   1 file changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/comedi/comedi_fops.c b/drivers/comedi/comedi_fops.c
> index 7e2f2b1a1c36..dea698e509b1 100644
> --- a/drivers/comedi/comedi_fops.c
> +++ b/drivers/comedi/comedi_fops.c
> @@ -2284,15 +2284,10 @@ static long comedi_unlocked_ioctl(struct file *file, unsigned int cmd,
>   		rc = check_insnlist_len(dev, insnlist.n_insns);
>   		if (rc)
>   			break;
> -		insns = kcalloc(insnlist.n_insns, sizeof(*insns), GFP_KERNEL);
> -		if (!insns) {
> -			rc = -ENOMEM;
> -			break;
> -		}
> -		if (copy_from_user(insns, insnlist.insns,
> -				   sizeof(*insns) * insnlist.n_insns)) {
> -			rc = -EFAULT;
> -			kfree(insns);
> +		insns = memdup_array_user(insnlist.insns, insnlist.n_insns,
> +					  sizeof(*insns));
> +		if (IS_ERR(insns)) {
> +			rc = PTR_ERR(insns);
>   			break;
>   		}
>   		rc = do_insnlist_ioctl(dev, insns, insnlist.n_insns, file);

Looks good to me.  Thanks!

Reviewed-by: Ian Abbott <abbotti@....co.uk>

-- 
-=( Ian Abbott <abbotti@....co.uk> || MEV Ltd. is a company  )=-
-=( registered in England & Wales.  Regd. number: 02862268.  )=-
-=( Regd. addr.: S11 & 12 Building 67, Europa Business Park, )=-
-=( Bird Hall Lane, STOCKPORT, SK3 0XA, UK. || www.mev.co.uk )=-