Re: amd64: kernel aslr support

[Maxime Villard <max%m00nbsd.net@localhost>]

Le 05/10/2017 à 00:59, Mouse a écrit :
> > Here is a Kernel ASLR implementation for NetBSD-amd64.  [...]
>
> > Contrary to what has been said in previous discussions, KASLR does
> > not alter debugability in any way: the symbols are still mapped in
> > memory as they are right now, and ddb resolves them as usual.
>
> I disagree that that's enough to "not alter debugability in any way".
> It makes common debugging tasks work, perhaps, but I have occasionally
> run into cases where all I have is a pc value (even less often, but
> it's still happened, a data address) and have had nothing but /netbsd's
> symbol table to help me make sense of it.

What I meant to say, is that the information ddb usually gives you is not
altered as a result of running KASLR; but you are right to say that it is
more complicated for you to get information by yourself manually.

(thinking about it, I could add the sections addresses in the ddb output,
and add a command to print %rip or whatever else relatively to the section
it finds itself in)

Maxime