Messages in this thread | | | Date | Mon, 19 Sep 2011 20:51:59 +0300 | Subject | Re: [kernel-hardening] Re: [RFC PATCH 2/2] mm: restrict access to /proc/slabinfo | From | Pekka Enberg <> |
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On Mon, Sep 19, 2011 at 8:35 PM, Vasiliy Kulikov <segoon@openwall.com> wrote: >> Yes, but there's no way for users to know where the allocations came from >> if you mix them up with other kmalloc-128 call-sites. That way the number >> of private files will stay private to the user, no? Doesn't that give you even >> better protection against the infoleak? > > No, what it gives us is an obscurity, not a protection. I'm sure it > highly depends on the specific situation whether an attacker is able to > identify whether the call is from e.g. ecryptfs or from VFS. Also the > correlation between the number in slabinfo and the real private actions > still exists.
How is the attacker able to identify that we kmalloc()'d from ecryptfs or VFS based on non-root /proc/slabinfo when the slab allocator itself does not have that sort of information if you mix up the allocations? Isn't this much stronger protection especially if you combine that with /proc/slabinfo restriction?
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