Re: [PATCH v2 0/5] Optionally randomize kernel stack offset each syscall
From: Kees Cook <hidden>
Date: 2020-03-25 20:27:07
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linux-mm, lkml
On Wed, Mar 25, 2020 at 12:15:12PM +0000, Reshetova, Elena wrote:
quoted
quoted
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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel