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From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: wangyangbo <yangbonis@icloud.com>, axboe@kernel.dk
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] loop: mask loop_control_ioctl parameter only as minor
Date: Thu, 18 Nov 2021 23:15:07 +0900	[thread overview]
Message-ID: <c685d6dc-3918-6ee5-df59-f2d814635228@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <20211118023640.32559-1-yangbonis@icloud.com>

On 2021/11/18 11:36, wangyangbo wrote:
> @@ -2170,11 +2170,11 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
>  {
>  	switch (cmd) {
>  	case LOOP_CTL_ADD:
> -		return loop_add(parm);
> +		return loop_add(MINOR(parm));

Better to return -EINVAL or something if out of minor range?

>  	case LOOP_CTL_REMOVE:
> -		return loop_control_remove(parm);
> +		return loop_control_remove(MINOR(parm));

This is bad, for this change makes

	if (idx < 0) {
		pr_warn("deleting an unspecified loop device is not supported.\n");
		return -EINVAL;
	}

dead code by masking the argument to 0-1048575 range.

>  	case LOOP_CTL_GET_FREE:
> -		return loop_control_get_free(parm);
> +		return loop_control_get_free(MINOR(parm));

This is pointless, for the passed argument is not used.
By the way, didn't someone already propose removal of this argument?

>  	default:
>  		return -ENOSYS;
>  	}
> 


  reply	other threads:[~2021-11-18 14:15 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-18  2:36 [PATCH] loop: mask loop_control_ioctl parameter only as minor wangyangbo
2021-11-18 14:15 ` Tetsuo Handa [this message]
2021-11-19  1:50   ` wangyangbo
2021-11-19  2:24 ` [PATCH] loop: check loop_control_ioctl parameter in range of minor wangyangbo
2021-11-19  2:32 ` [PATCH v2] " wangyangbo

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