Messages in this thread | | | Date | Wed, 25 Mar 2020 13:27:02 -0700 | From | Kees Cook <> | Subject | Re: [PATCH v2 0/5] Optionally randomize kernel stack offset each syscall |
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On Wed, Mar 25, 2020 at 12:15:12PM +0000, Reshetova, Elena wrote: > > > Also, are you sure that it isn't possible to make the syscall that > > > leaked its stack pointer never return to userspace (via ptrace or > > > SIGSTOP or something like that), and therefore never realign its > > > stack, while keeping some controlled data present on the syscall's > > > stack? > > How would you reliably detect that a stack pointer has been leaked > to userspace while it has been in a syscall? Does not seem to be a trivial > task to me.
Well, my expectation is that folks using this defense are also using panic_on_warn sysctl, etc, so attackers don't get a chance to actually _use_ register values spilled to dmesg.
-- Kees Cook
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