From: Florian Weimer <fweimer@redhat.com>
To: Topi Miettinen via Libc-alpha <libc-alpha@sourceware.org>
Cc: Topi Miettinen <toiwoton@gmail.com>
Subject: Re: Randomize offset between program segments?
Date: Wed, 21 Oct 2020 07:33:26 +0200 [thread overview]
Message-ID: <87y2k016u1.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <f7ce6a45-358e-f024-def3-ef3c223a241e@gmail.com> (Topi Miettinen via Libc-alpha's message of "Mon, 19 Oct 2020 18:31:47 +0300")
* Topi Miettinen via Libc-alpha:
> I'd like to improve address space randomization (ASLR) by randomizing
> the offset between .text, .data and .bss segments (or more
> generalized, any program segments). With large code generation model
> (-mcmodel=large) on AMD64, the offset could be very large, but even
> with the default model, the segments could be randomized within range
> of RIP-relative accesses (+/-2GB). Currently the dynamic loader can't
> randomize the segments (nothing also tells it if this would be OK) so
> it maps them next to each other, which is predictable and boring.
As far as I understand it, -mcmodel=large does not really work right now
with a stock toolchain.
But what you are asking for looks more like FDPIC support to me anyway.
I do not think it's particularly useful to implement this for targets
which have an MMU, to be honest.
Thanks,
Florian
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next prev parent reply other threads:[~2020-10-21 5:33 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-19 15:31 Topi Miettinen
2020-10-21 2:21 ` Siddhesh Poyarekar
2020-10-21 7:40 ` Topi Miettinen
2020-10-21 9:14 ` Siddhesh Poyarekar
2020-10-21 9:34 ` Topi Miettinen
2020-10-21 9:54 ` Siddhesh Poyarekar
2020-10-21 10:44 ` Topi Miettinen
2020-10-29 8:04 ` Siddhesh Poyarekar
2020-10-30 15:37 ` Topi Miettinen
2020-10-21 5:33 ` Florian Weimer [this message]
2020-10-21 8:02 ` Topi Miettinen
2020-10-21 8:06 ` Florian Weimer
2020-10-21 9:28 ` Topi Miettinen
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