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Date: Mon, 3 Aug 2020 20:48:17 -0400
From: "Frank Ch. Eigler" <>
To: Kees Cook <>
Cc: Joe Lawrence <>,
	Evgenii Shatokhin <>,
	Kristen Carlson Accardi <>,
	Miroslav Benes <>,,,,,,,,,, Josh Poimboeuf <>,
	Jessica Yu <>
Subject: Re: [PATCH v4 00/10] Function Granular KASLR

Hi -

> > We have relocated based on sections, not some subset of function
> > symbols accessible that way, partly because DWARF line- and DIE- based
> > probes can map to addresses some way away from function symbols, into
> > function interiors, or cloned/moved bits of optimized code.  It would
> > take some work to prove that function-symbol based heuristic
> > arithmetic would have just as much reach.
> Interesting. Do you have an example handy? 

No, I'm afraid I don't have one that I know cannot possibly be
expressed by reference to a function symbol only.  I'd look at
systemtap (4.3) probe point lists like:

% stap -vL 'kernel.statement("*@...nel/*verif*.c:*")'
% stap -vL 'module("amdgpu").statement("*@...ecution*.c:*")'

which give an impression of computed PC addresses.

> It seems like something like that would reference the enclosing
> section, which means we can't just leave them out of the sysfs
> list... (but if such things never happen in the function-sections,
> then we *can* remove them...)

I'm not sure we can easily prove they can never happen there.

- FChE

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