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

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Date:	Fri, 20 May 2016 14:27:05 +0200
From:	Samuel Thibault <samuel.thibault@...-lyon.org>
To:	Muhammad Falak R Wani <falakreyaz@...il.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.com>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Pavel Machek <pavel@....cz>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] tty/vt/keyboard: use memdup_user().

Muhammad Falak R Wani, on Fri 20 May 2016 17:53:28 +0530, wrote:
> Use memdup_user to duplicate a memory region from user-space to
> kernel-space, instead of open coding using kmalloc & copy_from_user.
> 
> Signed-off-by: Muhammad Falak R Wani <falakreyaz@...il.com>

Reviewed-by: Samuel Thibault <samuel.thibault@...-lyon.org>

> ---
>  drivers/tty/vt/keyboard.c | 14 ++++----------
>  1 file changed, 4 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
> index f973bfc..698ea43 100644
> --- a/drivers/tty/vt/keyboard.c
> +++ b/drivers/tty/vt/keyboard.c
> @@ -1745,16 +1745,10 @@ 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,
> +					  ct * sizeof(struct kbdiacruc));
> +			if (IS_ERR(buf))
> +				return PTR_ERR(buf);
>  		} 
>  		spin_lock_irqsave(&kbd_event_lock, flags);
>  		if (ct)
> -- 
> 1.9.1
> 

-- 
Samuel
(03:13:14) <j> bon
(03:13:19) <j> il est tard :p
(03:13:25) <g> c'est l'heure de manger
(03:13:38) <j> hm j'ai mangé à 1h moi, j'ai des horaires raisonnables