kernel-hardening - Re: [PATCH 2/3] x86: build reloc tool for both 64 and 32 bit

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Message-ID: <20130405071322.GC26889@gmail.com>
Date: Fri, 5 Apr 2013 09:13:22 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Kees Cook <keescook@...omium.org>
Cc: linux-kernel@...r.kernel.org, kernel-hardening@...ts.openwall.com,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, x86@...nel.org,
	Jarkko Sakkinen <jarkko.sakkinen@...el.com>,
	Matthew Garrett <mjg@...hat.com>,
	Matt Fleming <matt.fleming@...el.com>,
	Eric Northup <digitaleric@...gle.com>,
	Dan Rosenberg <drosenberg@...curity.com>,
	Julien Tinnes <jln@...gle.com>, Will Drewry <wad@...omium.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 2/3] x86: build reloc tool for both 64 and 32 bit


* Kees Cook <keescook@...omium.org> wrote:

> Add logic for 64-bit kernel relocations. Since there is no need to
> handle 32 and 64 bit at the same time, refactor away most of the 32/64
> bit ELF differences and split the build into producing two separate
> binaries. Additionally switches to using realloc instead of a two-pass
> approach.
> 
> Heavily based on work by Neill Clift and Michael Davidson.
> 
> Signed-off-by: Kees Cook <keescook@...omium.org>
> Cc: Eric Northup <digitaleric@...gle.com>
> ---
>  arch/x86/boot/compressed/Makefile |    2 +-
>  arch/x86/realmode/rm/Makefile     |    2 +-
>  arch/x86/tools/.gitignore         |    3 +-
>  arch/x86/tools/Makefile           |   14 +-
>  arch/x86/tools/relocs.c           |  717 ++++++++++++++++++++++++++-----------
>  arch/x86/tools/relocs_32.c        |    1 +
>  arch/x86/tools/relocs_64.c        |    2 +
>  7 files changed, 533 insertions(+), 208 deletions(-)
>  create mode 100644 arch/x86/tools/relocs_32.c
>  create mode 100644 arch/x86/tools/relocs_64.c

This patch too is a bit large and it would be wise to split it into two 
steps: first the refactoring - which is non-functional and should not 
cause any problems in theory - then the change that switches to realloc.

Thanks,

	Ingo

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