Messages in this thread | | | Date | Fri, 29 May 2020 13:14:56 -0700 | From | Kees Cook <> | Subject | Re: [PATCH v2 1/3] seccomp: Add find_notification helper |
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On Fri, May 29, 2020 at 05:40:38PM +0000, Sargun Dhillon wrote: > > > > While the comment is good, let's actually enforce this with: > > > > if (WARN_ON(!mutex_is_locked(&filter->notif_lock))) > > return NULL; > > > I don't see much use of lockdep in seccomp (well, any), but > wouldn't a stronger statement be to use lockdep, and just have: > > lockdep_assert_held(&filter->notify_lock); > > As that checks that the lock is held by the current task.
/me slaps his forehead
Yes. I need more coffee or something. Yes, I meant lockdep_assert_held(), and now I need to go fix my pstore series since I confused myself into the wrong function and using it so many times in pstore overwrote the correct function in my head. Thank you!
> Although, that does put this check behind lockdep, which means > that running in "normal" circumstances is less safe (but faster?).
Now, that's fine. The check needs to be "am *I* holding this mutex?" and I don't think anything except lockdep can do that.
-- Kees Cook
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