From mboxrd@z Thu Jan  1 00:00:00 1970
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [patch 2/8] allow unprivileged umount
Date: Sat, 21 Apr 2007 01:01:58 -0700
Message-ID: <4629C4F6.5070907@zytor.com>
References: <20070420102532.385211890@szeredi.hu>	<20070420102626.825263599@szeredi.hu> <20070421005506.6a315bec.akpm@linux-foundation.org>
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Cc: Miklos Szeredi <miklos@szeredi.hu>, serue@us.ibm.com,
	viro@ftp.linux.org.uk, linuxram@us.ibm.com, ebiederm@xmission.com,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	containers@lists.osdl.org
To: Andrew Morton <akpm@linux-foundation.org>
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Andrew Morton wrote:
> On Fri, 20 Apr 2007 12:25:34 +0200 Miklos Szeredi <miklos@szeredi.hu> wrote:
> 
>> +static bool permit_umount(struct vfsmount *mnt, int flags)
>> +{
>>
>> ...
>>
>> +	return mnt->mnt_uid == current->uid;
>> +}
> 
> Yes, this seems very wrong.  I'd have thought that comparing user_struct*'s
> would get us a heck of a lot closer to being able to support aliasing of
> UIDs between different namespaces.
> 

Not to mention it should be fsuid, not uid.

	-hpa