From: "H.J. Lu" <hjl.tools@gmail.com>
To: Florian Weimer <fw@deneb.enyo.de>
Cc: "Carlos O'Donell" <carlos@redhat.com>,
Generic System V Application Binary Interface
<generic-abi@googlegroups.com>,
gnu-gabi@sourceware.org
Subject: Re: RFC: Audit external function called indirectly via GOT
Date: Mon, 01 Jan 2018 00:00:00 -0000 [thread overview]
Message-ID: <CAMe9rOqUCm34a_c4PYUOHCPXZu0C234eYm7SAQ49B0DKifCBUA@mail.gmail.com> (raw)
In-Reply-To: <874ll8uker.fsf@mid.deneb.enyo.de>
On Thu, Mar 22, 2018 at 9:47 AM, Florian Weimer <fw@deneb.enyo.de> wrote:
> * Carlos O'Donell:
>
>> Well, Levin's "Linker's and Loaders"
>> https://www.iecc.com/linker/linker10.html, is the immediate reference
>> that I have on my shelf, and that developers working on glibc/binutils
>> should read.
>
> Thanks, I didn't know that.
>
>>> My understanding is that H.J.'s proposal requires changes when running
>>> in non-audit mode. It certainly requires relinking all binaries,
>>> perhaps even with special flags.
>>
>> It would require a relink only to fix existing binaries which are broken
>> by the use of -fno-plt, which is not an option that has seen general use
>> anywhere that I am aware of.
>
> I don't think that's actually true. BFD ld has not emitted
> R_X86_64_JUMP_SLOT relocations with -z now for quite some time now.
> This optimization predates -fno-plt.
>
Not true with binutils 2.30:
[hjl@gnu-bdx-1 include]$ readelf -d /bin/ld | grep NOW
0x0000000000000018 (BIND_NOW)
0x000000006ffffffb (FLAGS_1) Flags: NOW PIE
[hjl@gnu-bdx-1 include]$ readelf -rW /bin/ld | grep JUMP_SLOT
00000000001b0868 0000000100000007 R_X86_64_JUMP_SLOT
0000000000000000 getenv@GLIBC_2.2.5 + 0
...
--
H.J.
next prev parent reply other threads:[~2018-03-22 17:00 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-01 0:00 H.J. Lu
2018-01-01 0:00 ` Cary Coutant
2018-01-01 0:00 ` Carlos O'Donell
2018-01-01 0:00 ` Cary Coutant
2018-01-01 0:00 ` Alan Modra
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Alan Modra
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Cary Coutant
2018-01-01 0:00 ` Cary Coutant
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Florian Weimer
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Florian Weimer
2018-01-01 0:00 ` Carlos O'Donell
2018-01-01 0:00 ` Florian Weimer
2018-01-01 0:00 ` Carlos O'Donell
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Carlos O'Donell
2018-01-01 0:00 ` Cary Coutant
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Cary Coutant
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Cary Coutant
2018-01-01 0:00 ` Florian Weimer
2018-01-01 0:00 ` H.J. Lu [this message]
2018-01-01 0:00 ` Florian Weimer
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Florian Weimer
2018-01-01 0:00 ` H.J. Lu
2018-01-01 0:00 ` Florian Weimer
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