Re: PATCH: PE COFF relocation overflow bug

[Mark Mitchell <mark at codesourcery dot com>]

--On Monday, July 08, 2002 10:50:18 AM +0930 Alan Modra 
<amodra@bigpond.net.au> wrote:


> On Sun, Jul 07, 2002 at 07:43:43PM -0000, Mark Mitchell wrote:
> > --On Sunday, July 07, 2002 9:20 PM +0930 Alan Modra
> > <amodra@bigpond.net.au>  wrote:
> > > Either this patch, or coffcode.h:coff_write_relocs is wrong, as the
> >
> > The coffcode.h one is wrong.  I checked this with the Microsoft compiler.
> > (And, if you think about it, the only consistent choice is >=; the 0xffff
> > tells you that you need to look in the relocation table. )  I can make
> > that change too, if you want.
> Please.  They need to be consistent.
OK.  But, I don't want to get entangled in doing a major cleanup -- I
don't have time.

> > > latter adds the extra reloc for reloc_count > 0xffff.  Also, it seems
> > > to me that you should be allocating the extra space #ifdef COFF_WITH_PE
> > > rather than when obj_pe.
> >
> > That doesn't work; this file is not #include'd elsewhere -- it's only
> > compiled once.  So, you need a runtime check; hence obj_pe.
> Hmm, it wouldn't be the first occurrence of #ifdef COFF_WITH_PE in
> cofflink.c
There's one other.  That use is ineffectual.  Nothing sets COFF_WITH_PE
when compiling cofflink.c, ever.  COFF_WITH_PE is only set in files
like pe-i386.c, and they don't include cofflink.c.

(I actually tried using COFF_WITH_PE first; it was when I figured out
it didn't work that I discovered obj_pe.)

> pe and coff objects, when configuring for a pe target.  That's why I
> suggested #ifdef COFF_WITH_PE, for consistency.  Of course, this might
> just be consistently wrong...
It's worse than that; it won't even fix the bug I found.

> Better might be to use obj_pe in all places that twiddle reloc_count.
> That way you could configure for a pe target and have some hope of
> building a coff object with 0xffff relocs.
Well, that might be cleaner.  But coffcode.h *does* get compiled
multiple times; it's included from every coff target.  So, using
COFF_WITH_PE does work in coffcode.h -- just not in cofflink.c.

I'd prefer to leave y'all to disentangle this mess.  May I check in the
fix, plus the twiddling from ">" to ">=" in coffcode.h?

--
Mark Mitchell                mark@codesourcery.com
CodeSourcery, LLC            http://www.codesourcery.com