linux-kernel - Re: [PATCH] tty: vt: use memdup

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Date:	Mon, 21 Dec 2015 12:04:05 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Rahul Pathak <rahulpathaklinux@...il.com>
Cc:	gregkh@...uxfoundation.org, jslaby@...e.com,
	samuel.thibault@...-lyon.org, pavel@....cz,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] tty: vt: use memdup_user to reuse the code

On Sun, Dec 20, 2015 at 12:15:33AM +0530, Rahul Pathak wrote:
> Fixing coccicheck warning which recommends to use memdup_user instead
> to reimplement its code, using memdup_user simplifies the code
> 
> ./drivers/tty/vt/keyboard.c:1709:9-16: WARNING opportunity for memdup_user
> ./drivers/tty/vt/keyboard.c:1752:9-16: WARNING opportunity for memdup_user
> 
> Signed-off-by: Rahul Pathak <rahulpathaklinux@...il.com>

Acked-by: Dmitry Torokhov <dmitry.torokhov@...il.com>

(assuming Greg will pick it up, otherwise I can take it through my
tree).

Thanks.

> ---
>  drivers/tty/vt/keyboard.c | 28 ++++++++--------------------
>  1 file changed, 8 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
> index 6f0336f..ec05360 100644
> --- a/drivers/tty/vt/keyboard.c
> +++ b/drivers/tty/vt/keyboard.c
> @@ -1706,16 +1706,10 @@ int vt_do_diacrit(unsigned int cmd, void __user *udp, int perm)
>  			return -EINVAL;
>  
>  		if (ct) {
> -			dia = kmalloc(sizeof(struct kbdiacr) * ct,
> -								GFP_KERNEL);
> -			if (!dia)
> -				return -ENOMEM;
> -
> -			if (copy_from_user(dia, a->kbdiacr,
> -					sizeof(struct kbdiacr) * ct)) {
> -				kfree(dia);
> -				return -EFAULT;
> -			}
> +			dia = memdup_user(a->kbdiacr,
> +					sizeof(struct kbdiacr) * ct);
> +			if (IS_ERR(dia))
> +				return PTR_ERR(dia);
>  		}
>  
>  		spin_lock_irqsave(&kbd_event_lock, flags);
> @@ -1749,16 +1743,10 @@ int vt_do_diacrit(unsigned int cmd, void __user *udp, int perm)
>  			return -EINVAL;
>  
>  		if (ct) {
> -			buf = kmalloc(ct * sizeof(struct kbdiacruc),
> -								GFP_KERNEL);
> -			if (buf == NULL)
> -				return -ENOMEM;
> -
> -			if (copy_from_user(buf, a->kbdiacruc,
> -					ct * sizeof(struct kbdiacruc))) {
> -				kfree(buf);
> -				return -EFAULT;
> -			}
> +			buf = memdup_user(a->kbdiacruc,
> +					sizeof(struct kbdiacruc) * ct);
> +			if (IS_ERR(buf))
> +				return PTR_ERR(buf);
>  		} 
>  		spin_lock_irqsave(&kbd_event_lock, flags);
>  		if (ct)
> -- 
> 2.1.4
> 

-- 
Dmitry
--
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