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Date: Sat, 28 Feb 2009 15:03:56 -0500
From: Charles Wilson <cygwin AT cwilson DOT fastmail DOT fm>
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Subject: Re: [1.7] rebaseall doesn't solve the problem
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Christopher Faylor wrote:
> It should be trivial to add this to binutils.  Doesn't it ultimately
> belong in ld and (maybe) objcopy?

Well, I'm sure it would be useful there.  However, just as ld can create
a DLL with a user-specified image base, yet we still have a separate
special purpose utility for rebasing them, it makes sense that ld can
create an exe or dll with a specific pe_dll_characteristics flag, but a
separate single-purpose utility to modify it is also useful.

I really don't want Q. Random User to try and run objcopy <confusing
options> on his entire installation...

> I can add this now but I don't think it should be the default just yet.

Agree.

BTW, this was mentioned on the binutils list about two years ago, but
nothing ever came of it:
http://sourceware.org/ml/binutils/2007-02/msg00046.html

> Do the exes themselves need this bit as well as the dlls?

From what I understand, ASLR makes sense for both DLLs and EXEs -- but
only if the image has relocations (most DLLs, and PIE exectuables).
TS-Aware makes sense only for EXEs according to Corinna.  NX could be
applied to any DLL or EXE (I think).

My mistake in the existing alsr code was to always skip if no
relocations -- so since we don't have PIE exes, you can't currently set
the TS or NX flags on ordinary exes with the tool.

--
Chuck


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