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From: Kees Cook <keescook@chromium.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: James Morris <jmorris@namei.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] securityfs: Add missing d_delete() call on removal
Date: Tue, 5 May 2020 20:28:33 -0700	[thread overview]
Message-ID: <202005052024.2D7626C742@keescook> (raw)
In-Reply-To: <20200506011431.GB23230@ZenIV.linux.org.uk>

On Wed, May 06, 2020 at 02:14:31AM +0100, Al Viro wrote:
> On Tue, May 05, 2020 at 04:40:35PM -0700, Kees Cook wrote:
> > After using simple_unlink(), a call to d_delete() is needed in addition
> > to dput().
> > 
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > Is this correct? I went looking around and there are a lot of variations
> > on the simple_unlink() pattern...
> > 
> > Many using explicit locking and combinations of d_drop(), __d_drop(), etc.
> 
> Quite a few of those should switch to simple_recursive_removal().  As for
> securityfs...  d_drop() is _probably_ a saner variant, but looking at the
> callers of that thing... at least IMA ones seem to be garbage.

Hmm, I dunno. I hadn't looked at these yet. I'm not sure what's needed
for those cases.

Is my patch to add d_delete() correct, though? I'm trying to construct
the right set of calls for pstore's filesystem, and I noticed that most
will do simple_unlink(), d_delete(), dput(), but securityfs seemed to be
missing it.

-- 
Kees Cook

  reply	other threads:[~2020-05-06  3:28 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-05 23:40 [PATCH] securityfs: Add missing d_delete() call on removal Kees Cook
2020-05-06  1:14 ` Al Viro
2020-05-06  3:28   ` Kees Cook [this message]
2020-05-06  4:02     ` Al Viro
2020-05-06 15:34       ` Kees Cook
2020-05-06 18:49         ` Al Viro
2020-05-06 22:49           ` Kees Cook

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