From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Mon, 27 Jul 2020 13:35:58 +0000
Subject: Re: [PATCH] mtd: unlock on error in ioctl
Message-Id: <20200727133558.GA28751@kroah.com>
List-Id: <kernel-janitors.vger.kernel.org>
References: <20200727112050.GF389488@mwanda>
In-Reply-To: <20200727112050.GF389488@mwanda>
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To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Vignesh Raghavendra <vigneshr@ti.com>, Richard Weinberger <richard@nod.at>, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, Miquel Raynal <miquel.raynal@bootlin.com>

On Mon, Jul 27, 2020 at 02:20:50PM +0300, Dan Carpenter wrote:
> We need to unlock before returning on this error path.
> 
> Fixes: 210bec567936 ("mtd: properly check all write ioctls for permissions")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
>  drivers/mtd/mtdchar.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
> index 52c120f9fb0d..05f9218592df 100644
> --- a/drivers/mtd/mtdchar.c
> +++ b/drivers/mtd/mtdchar.c
> @@ -1064,8 +1064,10 @@ static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
>  		struct mtd_oob_buf32 buf;
>  		struct mtd_oob_buf32 __user *buf_user = argp;
>  
> -		if (!(file->f_mode & FMODE_WRITE))
> -			return -EPERM;
> +		if (!(file->f_mode & FMODE_WRITE)) {
> +			ret = -EPERM;
> +			goto unlock;
> +		}
>  
>  		if (copy_from_user(&buf, argp, sizeof(buf)))
>  			ret = -EFAULT;
> @@ -1117,6 +1119,7 @@ static long mtdchar_compat_ioctl(struct file *file, unsigned int cmd,
>  		ret = mtdchar_ioctl(file, cmd, (unsigned long)argp);
>  	}
>  
> +unlock:
>  	mutex_unlock(&mtd_mutex);
>  
>  	return ret;
> -- 
> 2.27.0
> 

I think this is already fixed up in the mtd tree.

thanks,

greg k-h