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From: Cary Coutant <ccoutant@gmail.com>
To: Florian Weimer <fweimer@redhat.com>
Cc: Nick Clifton <nickc@redhat.com>,
	gnu-gabi@sourceware.org, 	"H.J. Lu" <hjl.tools@gmail.com>
Subject: Re: RFA: Add a new gynamic tag: DT_GNU_GOT_PLT_END
Date: Mon, 01 Jan 2018 00:00:00 -0000	[thread overview]
Message-ID: <CAJimCsEPoFYN0kT6zZHGVsQAqu0Hy0=+1OZMJNAJFaEP3KdhDA@mail.gmail.com> (raw)
In-Reply-To: <df85d9ff-9cd6-44bb-16c5-d6d545896cca@redhat.com>

>> That leads me to another question: How would this be different from -z
>> relro -z now? It looks to me like a binary with such a PLT GOT would
>> be nothing more than a -z relro -z now binary where nothing but the
>> .got.plt section ends up as RELRO. So why not just use the
>> PT_GNU_RELRO program header for this?
>
> It doesn't disable lazy binding, so there is no visible semantic difference
> in symbol binding.
>
> With page isolation, we can use pkey_mprotect to assign a protection key to
> the .got.plt and only make it readable while _dl_fixup is running. That
> would provide most of the security benefits of BIND_NOW+RELRO, without
> disabling lazy binding.

OK, so it's a variant of RELRO. I'd prefer using a new program header
type, PT_GNU_PLTGOT, then.

-cary

  reply	other threads:[~2018-06-24 21:05 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <87sh5hadd6.fsf@redhat.com>
     [not found] ` <CAMe9rOrFiHvUj4EeviT8UdA2b8b_FpiPofeNqRyWzNA9286ZNQ@mail.gmail.com>
2018-01-01  0:00   ` Nick Clifton
2018-01-01  0:00     ` Cary Coutant
2018-01-01  0:00       ` Cary Coutant
2018-01-01  0:00       ` Florian Weimer
2018-01-01  0:00         ` Cary Coutant
2018-01-01  0:00           ` Florian Weimer
2018-01-01  0:00             ` Cary Coutant [this message]
2018-01-01  0:00               ` Florian Weimer
2018-01-01  0:00                 ` Cary Coutant
2018-01-01  0:00                   ` Florian Weimer

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