Messages in this thread | | | Date | Wed, 28 Mar 2012 11:33:15 -0700 | Subject | Re: [PATCH] futex: do not leak robust list to unprivileged process | From | Kees Cook <> |
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On Thu, Mar 22, 2012 at 4:46 PM, Thomas Gleixner <tglx@linutronix.de> wrote: > On Tue, 20 Mar 2012, Ingo Molnar wrote: >> * Kees Cook <keescook@chromium.org> wrote: >> > On Tue, Mar 20, 2012 at 10:02 AM, Thomas Gleixner <tglx@linutronix.de> wrote: >> > > I really wonder why we have this syscall at all. >> > >> > The documentation I found yesterday while looking at this was: >> > http://linux.die.net/man/2/get_robust_list >> > >> > Which says "The system call is only available for debugging >> > purposes and is not needed for normal operations. Both system >> > calls are not available to application programs as functions; >> > they can be called using the syscall(3) function." >> > >> > Dropping the syscall entirely would certainly make it secure. >> > ;) >> >> The thinking was API completeness. In general it's possible for >> a sufficiently privileged task to figure out all the state of a >> task. We can query timers, fds - the robust list is such a >> resource as well. The information leakage was obviously not >> intended. > > So I think it's safe to take Kees' patch as is. On top of that we > should add a WARN_ONCE when the syscall is invoked and schedule the > sucker for removal.
Can someone claim the first patch? It looks like not everyone agrees about removal, but I'd like to see at least the first one get in. :)
-Kees
-- Kees Cook ChromeOS Security
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