Re: [PATCH] libc.so: Replace nscd_hash.os with libc-nscd_hash.os [BZ #22459]

[Florian Weimer <fweimer at redhat dot com>]

On 11/20/2017 02:02 PM, H.J. Lu wrote:
> On Mon, Nov 20, 2017 at 1:02 AM, Florian Weimer <fweimer@redhat.com> wrote:
> > On 11/19/2017 08:44 PM, H.J. Lu wrote:
> > > nscd_hash.os is needed both libc.so as well as nscd.  Since nscd_hash.os
> > > is compiled as the part of nscd, when -fstack-protector-all is used,
> > > nscd_hash.os calls __stack_chk_fail via PLT, which leads to
> > >
> > > FAIL: elf/check-localplt
> > > Extra PLT reference: libc.so: __stack_chk_fail
> > >
> > > This patch replaces nscd_hash.os with libc-nscd_hash.os in libc_pic.a
> > > to avoid calling __stack_chk_fail via PLT inside of libc.so.
> > >
> > > Any comments?
> >
> >
> > Considering that nscd/nscd_hash.c is itself another #include wrapper, I
> > think it is time to clean this up.
> >
> > The hash function algorithm is already part of the public ABI because the
> > nscd mappings require it, so we might as well export it, which is
> > implemented in the attached patch.
>
> Do we need to export it in GLIBC_2.27 space?  I prefer GLIBC_PRIVATE.
> Otherwise, it looks good to me.

The libnsl symbol isn't GLIBC_PRIVATE, but perhaps should have been.

I'm somewhat in favor of exporting this because independent nscd 
implementations will need to implement the exact same hash function.

Thanks,
Florian