Re: [kernel-hardening] Re: [RFC 0/3] kallsyms: don't leak address when printing symbol

From: Kaiwan N Billimoria
Date: Mon Nov 27 2017 - 22:29:12 EST


On Tue, Nov 28, 2017 at 7:20 AM, Tobin C. Harding <me@xxxxxxxx> wrote:
>
> Noob question: how do we _know_ this. In other words how do we know no
> userland tools rely on the current behaviour? No stress to answer Kees,
> this is a pretty general kernel dev question.

Perhaps I'm reading this wrong, but anyway: besides ftrace, kprobes
will require a
symbol-to-address lookup. Specifically, in the function
kprobe_lookup_name() which
in turn invokes kallsyms_lookup_name().
AFAIK, SystemTap (userland) is built on top of the kprobes infrastructure..

thanks,
Kaiwan.