Messages in this thread | | | Date | Wed, 6 May 2020 08:34:29 -0700 | From | Kees Cook <> | Subject | Re: [PATCH] securityfs: Add missing d_delete() call on removal |
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On Wed, May 06, 2020 at 05:02:52AM +0100, Al Viro wrote: > On Tue, May 05, 2020 at 08:28:33PM -0700, Kees Cook wrote: > > 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. > > d_drop(). d_delete() is for the situations when you want the sucker > to become a hashed negative, if at all possible.
I'm not sure what that means. :) Should stuff like apparmorfs be changed to d_drop()?
> Re pstore: context, please.
Just posted the whole series: https://lore.kernel.org/lkml/20200506152114.50375-1-keescook@chromium.org/
But the specific question was driven by this patch: https://lore.kernel.org/lkml/20200506152114.50375-11-keescook@chromium.org/
-- Kees Cook
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