[PATCH v2] static-pie: Skip the empty PT_LOAD segment at offset 0 [BZ #32763]

[H.J. Lu]

On Thu, Mar 6, 2025 at 6:48 AM Sam James <sam@gentoo.org> wrote:
>
> "H.J. Lu" <hjl.tools@gmail.com> writes:
>
> > On Wed, Mar 5, 2025 at 11:02 AM H.J. Lu <hjl.tools@gmail.com> wrote:
> >>
> >> As shown in
> >>
> >> https://sourceware.org/bugzilla/show_bug.cgi?id=32761
> >>
> >> linker may generate more than one PT_LOAD segments at offset 0
> >>
> >
> > This is intentional.  Here is the v2 patch:
> >
> > As shown in
> >
> > https://sourceware.org/bugzilla/show_bug.cgi?id=25237
> >
> > linker may generate an empty PT_LOAD segments at offset 0:
> >
> > Elf file type is EXEC (Executable file)
> > Entry point 0x4000e8
> > There are 3 program headers, starting at offset 64
> >
> > Program Headers:
> >   Type           Offset             VirtAddr           PhysAddr
> >                  FileSiz            MemSiz              Flags  Align
> >   LOAD           0x0000000000000000 0x0000000000400000 0x0000000000400000
> >                  0x00000000000000f0 0x00000000000000f0  R E    0x1000
> >   LOAD           0x0000000000000000 0x0000000000410000 0x0000000000410000
> >                  0x0000000000000000 0x0000000000b5dce8  RW     0x10000
> >   GNU_STACK      0x0000000000000000 0x0000000000000000 0x0000000000000000
> >                  0x0000000000000000 0x0000000000000000  RW     0x10
> >
> >  Section to Segment mapping:
> >   Segment Sections...
> >    00     .text
> >    01     .bss
> >    02
> >
> > Skip the empty PT_LOAD segment at offset 0 to support such binaries.
> > This fixes BZ #32763.
>
> Thanks. It looks good to me after reviewing the other linker bugs and
> Alan's linker change.

Here is the v3 patch I am checking in.  The main addition is

@@ -2082,6 +2086,7 @@ $(objpfx)tst-array5-static-cmp.out: tst-array5-static.exp
\

 CFLAGS-tst-pie1.c += $(pie-ccflag)
 CFLAGS-tst-pie2.c += $(pie-ccflag)
+CFLAGS-tst-pie-bss.c += $(pie-ccflag)
 CFLAGS-tst-pie-address.c += $(pie-ccflag)

 $(objpfx)tst-piemod1.so: $(libsupport)

for glibc configured with --disable-default-pie

-- 
H.J.
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