linux-kernel - Re: [PATCH 1/8] x86, kaslr: get kaslr

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Message-ID: <CAE9FiQV6EnF-3eb97-wtdfyfr5T=HZtpxHnmTYK4OGMyYwKq0w@mail.gmail.com>
Date:	Mon, 2 Mar 2015 14:10:22 -0800
From:	Yinghai Lu <yinghai@...nel.org>
To:	Borislav Petkov <bp@...e.de>
Cc:	Ingo Molnar <mingo@...nel.org>, Jiri Kosina <jkosina@...e.cz>,
	Kees Cook <keescook@...omium.org>,
	Matt Fleming <matt.fleming@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>
Subject: Re: [PATCH 1/8] x86, kaslr: get kaslr_enabled back correctly

On Mon, Mar 2, 2015 at 12:25 PM, Borislav Petkov <bp@...e.de> wrote:

>  unsigned char *choose_kernel_location(struct boot_params *params,
> diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S
> index 34d047c98284..26d62f4b27b9 100644
> --- a/arch/x86/boot/compressed/vmlinux.lds.S
> +++ b/arch/x86/boot/compressed/vmlinux.lds.S
> @@ -29,6 +29,10 @@ SECTIONS
>         .rodata..compressed : {
>                 *(.rodata..compressed)
>         }
> +       .setup_data : {
> +               _setup_data = . ;
> +               *(.setup_data)
> +       }
>         .text : {
>                 _text = .;      /* Text */
>                 *(.text)

That does not help, we will still have overlap between copied Zo
vmlinux and decompressed Vo vmlinux

because the Zo vmlinux is copied to middle of buffer instead of end of
the buffer.

definition:
Zo vmliunx: arch/x86/boot/compressed/vmlinux, from
arch/x86/boot/compressed/vmlinux.lds.S
Vo vmlinux: vmlinux from arch/x86/kernel/vmlinux.lds.S

BTW, found more problem about run_size for kaslr, we should use
init_size instead.

Here the three patches that should go into v4.0. Help Ingo will be
happy with updated change log.

Thanks

Yinghai

View attachment "use_init_size_instead_of_run_size.patch" of type "text/x-patch" (7639 bytes)

View attachment "fix_decompress_offset.patch" of type "text/x-patch" (6418 bytes)

View attachment "fix_kaslr.patch" of type "text/x-patch" (1405 bytes)