This is the mail archive of the
mailing list for the binutils project.
Re: [PATCH] i386: Remove PLT0 and use non-lazy PLT if PLT0 is unused
On Sat, May 6, 2017 at 11:55 AM, Florian Weimer <email@example.com> wrote:
> On 05/06/2017 05:11 PM, H.J. Lu wrote:
>> 1. Call external function.
>> 2. Call internal IFUNC function. The best implementation is selected
>> for the target processor at run-time.
>> 3. Act as the canonical function address.
> Audit support is missing from this list. Audit support needs a PLT stub
> which calls the audit trampoline with some sort of function index or
This behavior disables LD_AUDIT support with -z now, in addition to
or compiling with -fno-plt. Also should LD_AUDIT work on external
calls inside shared objects linked with -z now?
> I'm concerned that -z now in recent binutils (even without this patch)
> removes audit support, when before, audit support was not impacted by -z now
> (I think, I'm not sure on this point).
> We really must avoid hardening flags which have profound semantic
> implications on generated binaries because it discourages people from
> enabling them.
The impacts for removing PLT0 with -z now are
1. LD_AUDIT no longer works.
1. Make the run-time behavior the same with "export LD_BIND_NOW=1".
2. Disable LD_AUDIT to further improve security.
I can add a new "-z audit" option to enable LD_AUDIT as much as
extern void foo (void);