Re: [PATCH 5/27] mm: Use memdup_user

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

> Signed-off-by: Julia Lawall <julia@diku.dk>
> 
> ---
>  mm/util.c |   11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
> 
> diff --git a/mm/util.c b/mm/util.c
> index f5712e8..4735ea4 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -225,15 +225,10 @@ char *strndup_user(const char __user *s, long n)
>  	if (length > n)
>  		return ERR_PTR(-EINVAL);
>  
> -	p = kmalloc(length, GFP_KERNEL);
> +	p = memdup_user(s, length);

memdup? Why can't we use strnlen_user() and legitimate length copy?


>  
> -	if (!p)
> -		return ERR_PTR(-ENOMEM);
> -
> -	if (copy_from_user(p, s, length)) {
> -		kfree(p);
> -		return ERR_PTR(-EFAULT);
> -	}
> +	if (IS_ERR(p))
> +		return p;
>  
>  	p[length - 1] = '\0';
>  
> 
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