From: Mark Kettenis <mark.kettenis@xs4all.nl>
Subject: Re: macppc ld.so: move check for unsupported PLT
To: George Koehler <kernigh@gmail.com>
Cc: tech@openbsd.org
Date: Sat, 22 Aug 2026 12:55:08 +0200

> Date: Fri, 21 Aug 2026 18:00:55 -0400
> From: George Koehler <kernigh@gmail.com>
> 
> Pike from https://pike.lysator.liu.se gave a strange error on macppc,
> 
> $ pike --features
> ld.so: pike: unsupported insecure BSS PLT object
> Killed
> 
> The PLT is for relocating function calls.  The old BSS PLT for powerpc
> is extinct.  Pike used ld -nostartmodules to link a module with no
> function calls.  This module has no PLT, and ld.so confused the
> absence of a PLT with the presence of a BSS PLT.  This diff fixes it
> by moving the check for the secure PLT (if PPC_GOT is nonzero) after
> the check for any kind of PLT (if PLTREL is RELA).  Now pike doesn't
> die, but if I make a BSS PLT, it still dies:
> 
> $ cc -fuse-ld=bfd -Wl,--bss-plt -o here here.c
> $ ./here
> ld.so: here: unsupported insecure BSS PLT object
> Killed
> 
> ok to commit?

ok kettenis@

> Index: powerpc/rtld_machine.c
> ===================================================================
> RCS file: /cvs/src/libexec/ld.so/powerpc/rtld_machine.c,v
> diff -u -p -r1.73 rtld_machine.c
> --- powerpc/rtld_machine.c	16 Jul 2026 11:21:37 -0000	1.73
> +++ powerpc/rtld_machine.c	21 Aug 2026 01:59:18 -0000
> @@ -74,9 +74,6 @@ _dl_md_reloc(elf_object_t *object, int r
>  	if (relrel > numrela)
>  		_dl_die("relcount > numrel: %ld > %d", relrel, numrela);
>  
> -	if (object->Dyn.info[DT_PROC(DT_PPC_GOT)] == 0)
> -		_dl_die("unsupported insecure BSS PLT object");
> -
>  	/* tight loop for leading RELATIVE relocs */
>  	for (i = 0; i < relrel; i++, relas++) {
>  		Elf_Addr *r_addr;
> @@ -273,6 +270,9 @@ _dl_md_reloc_got(elf_object_t *object, i
>  
>  	if (object->Dyn.info[DT_PLTREL] != DT_RELA)
>  		return 0;
> +
> +	if (object->Dyn.info[DT_PROC(DT_PPC_GOT)] == 0)
> +		_dl_die("unsupported insecure BSS PLT object");
>  
>  	if (!lazy) {
>  		fails = _dl_md_reloc(object, DT_JMPREL, DT_PLTRELSZ);
> 
>