Re: [PATCH] powerpc/nvram: use memdup_user

From: Kees Cook
Date: Tue Jun 27 2017 - 20:08:16 EST


On Fri, Apr 28, 2017 at 6:45 PM, Geliang Tang <geliangtang@xxxxxxxxx> wrote:
> Use memdup_user() helper instead of open-coding to simplify the code.
>
> Signed-off-by: Geliang Tang <geliangtang@xxxxxxxxx>

Thanks! Applied for -next.

-Kees

> ---
> arch/powerpc/kernel/nvram_64.c | 14 +++++---------
> 1 file changed, 5 insertions(+), 9 deletions(-)
>
> diff --git a/arch/powerpc/kernel/nvram_64.c b/arch/powerpc/kernel/nvram_64.c
> index eae61b0..496d639 100644
> --- a/arch/powerpc/kernel/nvram_64.c
> +++ b/arch/powerpc/kernel/nvram_64.c
> @@ -792,21 +792,17 @@ static ssize_t dev_nvram_write(struct file *file, const char __user *buf,
> count = min_t(size_t, count, size - *ppos);
> count = min(count, PAGE_SIZE);
>
> - ret = -ENOMEM;
> - tmp = kmalloc(count, GFP_KERNEL);
> - if (!tmp)
> - goto out;
> -
> - ret = -EFAULT;
> - if (copy_from_user(tmp, buf, count))
> + tmp = memdup_user(buf, count);
> + if (IS_ERR(tmp)) {
> + ret = PTR_ERR(tmp);
> goto out;
> + }
>
> ret = ppc_md.nvram_write(tmp, count, ppos);
>
> -out:
> kfree(tmp);
> +out:
> return ret;
> -
> }
>
> static long dev_nvram_ioctl(struct file *file, unsigned int cmd,
> --
> 2.9.3
>



--
Kees Cook
Pixel Security