Question - intention of UCLIBC_BUILD_NOEXECSTACK?

Khem Raj raj.khem at gmail.com
Tue Aug 26 20:01:08 UTC 2014


On 14-08-26 21:35:57, Bernhard Reutner-Fischer wrote:
> On 25 August 2014 15:57, Andrew McDonnell <bugs at andrewmcdonnell.net> wrote:
> > On 25/08/14 22:56, Andrew McDonnell wrote:
> >> Hmmm, I am having some trouble repeating my original result.
> >>
> > <snipped>
> >
> > OK, with a fresh build, the following appears to apply:
> >
> > * OpenWRT sets UCLIBC_BUILD_NOEXECSTACK=y
> >
> > * Somehow this ends up with libcrypt, libm, libresolv, libnsl, libthread_db,
> > libdl and  and libutil actually having the NX flag set in the ELF despite
> > there being no -Wl,-z,noexecstack linker option specified.
> >
> > This I really do not understand yet!
> >
> > * ld-uClibc, librt, libuClibc and libpthread _dont have the NX flag set, which
> > is what I would have expected when the link was missing the noexecstack option.
> >
> > * The above was checked before any stripping applied, just in case
> >
> > Now its gotten too late, so I'll have to re-test my patch that applies the
> > noexecstack marking to ld-uClibc, librt, libuClibc and libpthread as well
> > later this week before I submit it.
> >
> > FWIW this is all done using the OpenWRT buildroot for a carambola2 target
> >
> > There is another oddity with all of this, as well.
> >
> > Every single one of libcrypt, libm, libresolv, libnsl, libthread_db, libdl,
> > libutil, libuClibc, librt and libpthread are all built with -Wl,-z-relro yet
> > the GNU_RELRO section is only present in libdl, libpthread and libuClibc and
> > yet all are built with exactly the same set of -Wl,-z options
> >
> > I am wondering if this is this bug,
> > https://sourceware.org/bugzilla/show_bug.cgi?id=16322 because OpenWRT binutils
> > is still 2.23
> 
> I cannot reproduce this with binutils-gdb 2.24.51.20140818.
> Can you try with binutils 2.24 or later please?

Are you trying OE binutils ? we have backported a patch into it for
textrels

> 
> TIA,
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