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From: Miklos Szeredi <miklos@szeredi.hu>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Amir Goldstein <amir73il@gmail.com>,
	"linux-unionfs@vger.kernel.org" <linux-unionfs@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH v3 1/6] vfs: create vfs helper vfs_tmpfile()
Date: Thu, 9 Mar 2017 12:13:29 +0100	[thread overview]
Message-ID: <CAJfpegsLHq8qhv+nBrgF3f0tM_LDLoOk1vTxpsdnwnc78hcppA@mail.gmail.com> (raw)
In-Reply-To: <20170219032743.GH29622@ZenIV.linux.org.uk>

On Sun, Feb 19, 2017 at 4:27 AM, Al Viro <viro@zeniv.linux.org.uk> wrote:
> On Mon, Jan 16, 2017 at 08:47:32PM +0100, Miklos Szeredi wrote:
>
>> > +                          umode_t mode, int open_flag)
>> > +{
>> > +       static const struct qstr name = QSTR_INIT("/", 1);
>> > +       struct dentry *child = NULL;
>> > +       struct inode *inode;
>> > +       int error;
>> > +
>> > +       /* we want directory to be writable */
>> > +       error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
>>
>> This is not in the scope of this patch, but shoudln't we be using
>> may_create() here?   Or at least a variant without the audit thing...
>>
>> Al?
>
> may_create() expects directory + child dentry; here we have only parent.
> IS_DEADDIR is rather pointless here - directory is not locked, for
> starters, so rmdir might happen right under you.  Or right after you've
> returned from your function, for that matter.  userns checks...
> FWIW, no such checks are done in ->atomic_open() paths, so I'm not sure
> how much are those worth...

Eric would know since he added those checks.

Thanks,
Miklos

  reply	other threads:[~2017-03-09 11:13 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-16 17:45 [PATCH v3 0/6] ovl: concurrent copy up Amir Goldstein
2017-01-16 17:46 ` [PATCH v3 1/6] vfs: create vfs helper vfs_tmpfile() Amir Goldstein
2017-01-16 19:47   ` Miklos Szeredi
2017-02-19  3:27     ` Al Viro
2017-03-09 11:13       ` Miklos Szeredi [this message]
2017-03-09 17:31         ` Eric W. Biederman
2017-03-09 17:31           ` Eric W. Biederman
2017-01-16 17:46 ` [PATCH v3 2/6] ovl: check if upperdir fs supports O_TMPFILE Amir Goldstein
2017-01-16 17:46 ` [PATCH v3 3/6] ovl: rearrange code in ovl_copy_up_locked() Amir Goldstein
2017-01-16 17:46 ` [PATCH v3 4/6] ovl: copy up regular file using O_TMPFILE Amir Goldstein
2017-04-05 18:32   ` Amir Goldstein
2017-04-05 19:36     ` Vivek Goyal
2017-01-16 17:46 ` [PATCH v3 5/6] ovl: introduce copy up waitqueue Amir Goldstein
2017-01-16 17:46 ` [PATCH v3 6/6] ovl: concurrent copy up of regular files Amir Goldstein

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