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From: Florian Weimer <fweimer@redhat.com>
To: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>,  nd <nd@arm.com>
Subject: Re: [RFC][AArch64] Add support for system register based stack protector canary access
Date: Tue, 04 Dec 2018 12:58:00 -0000	[thread overview]
Message-ID: <87va49ih3j.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <HE1PR08MB1035E1E335F7344C8EDE002C83AF0@HE1PR08MB1035.eurprd08.prod.outlook.com>	(Wilco Dijkstra's message of "Tue, 4 Dec 2018 03:51:02 +0000")

* Wilco Dijkstra:

>> For userland, I would like to eventually copy the OpenBSD approach for
>> architectures which have some form of PC-relative addressing: we can
>> have multiple random canaries in (RELRO) .rodata in sufficiently close
>> to the code that needs them (assuming that we have split .rodata).  At
>> least for x86-64, I expect this to be a small win.  It's also a slight
>> hardening improvement if the reference canary is not stored in writable
>> memory.
>
> On AArch64 hardware pointer signing already provides a free and more robust
> implementation of stack canaries, so we could change -fstack-protector to
> use that when pointer signing is enabled.

I expected to use both because not all AArch64 implementations support
pointer signing, and we'd use the stack protector to get some coverage
for the legacy implementations.

(I'm still waiting for a request to enable pointer signing in Fedora
rawhide, BTW.)

Thanks,
Florian

  reply	other threads:[~2018-12-04 12:58 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-04  3:51 Wilco Dijkstra
2018-12-04 12:58 ` Florian Weimer [this message]
2018-12-07 14:51   ` Ramana Radhakrishnan
  -- strict thread matches above, loose matches on Subject: below --
2018-12-03  9:55 Ramana Radhakrishnan
2018-12-03  9:59 ` Jakub Jelinek
2018-12-03 10:03   ` Ramana Radhakrishnan
2018-12-03 15:31 ` Florian Weimer
2018-12-03 16:40 ` Ard Biesheuvel
2019-01-10 16:53   ` Ramana Radhakrishnan
2019-01-10 10:53 ` Ramana Radhakrishnan
2019-01-10 11:05   ` Jakub Jelinek
2019-01-10 12:51     ` Ramana Radhakrishnan
2019-01-10 15:49 ` James Greenhalgh
2019-01-10 15:55   ` Will Deacon
2019-01-10 16:49   ` Ramana Radhakrishnan
2019-01-19 17:30 ` Jakub Jelinek

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