linux-kernel - Re: [PATCH] ima: use memdup_user

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Message-Id: <1494258275.5871.1.camel@linux.vnet.ibm.com>
Date:   Mon, 08 May 2017 11:44:35 -0400
From:   Mimi Zohar <zohar@...ux.vnet.ibm.com>
To:     Geliang Tang <geliangtang@...il.com>,
        Dmitry Kasatkin <dmitry.kasatkin@...il.com>,
        James Morris <james.l.morris@...cle.com>,
        "Serge E. Hallyn" <serge@...lyn.com>
Cc:     linux-ima-devel@...ts.sourceforge.net,
        linux-ima-user@...ts.sourceforge.net,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ima: use memdup_user_nul

On Sat, 2017-05-06 at 23:40 +0800, Geliang Tang wrote:
> Use memdup_user_nul() helper instead of open-coding to simplify the
> code.
> 
> Signed-off-by: Geliang Tang <geliangtang@...il.com>

Thanks, this patch will be queued.

Mimi

> ---
>  security/integrity/ima/ima_fs.c | 13 ++++---------
>  1 file changed, 4 insertions(+), 9 deletions(-)
> 
> diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
> index ca303e5..ad491c5 100644
> --- a/security/integrity/ima/ima_fs.c
> +++ b/security/integrity/ima/ima_fs.c
> @@ -323,16 +323,11 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
>  	if (*ppos != 0)
>  		goto out;
> 
> -	result = -ENOMEM;
> -	data = kmalloc(datalen + 1, GFP_KERNEL);
> -	if (!data)
> +	data = memdup_user_nul(buf, datalen);
> +	if (IS_ERR(data)) {
> +		result = PTR_ERR(data);
>  		goto out;
> -
> -	*(data + datalen) = '\0';
> -
> -	result = -EFAULT;
> -	if (copy_from_user(data, buf, datalen))
> -		goto out_free;
> +	}
> 
>  	result = mutex_lock_interruptible(&ima_write_mutex);
>  	if (result < 0)