Re: [PATCH v8 0/2] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions

From: Chao Fan <fanc.fnst@cn.fujitsu.com>
To: Baoquan He <bhe@redhat.com>
Cc: <linux-kernel@vger.kernel.org>, <mingo@kernel.org>,
	<matt@codeblueprint.co.uk>, <keescook@chromium.org>,
	<tglx@linutronix.de>, <hpa@zytor.com>,
	<izumi.taku@jp.fujitsu.com>, <thgarnie@google.com>,
	<n-horiguchi@ah.jp.nec.com>, <ard.biesheuvel@linaro.org>,
	<linux-efi@vger.kernel.org>, <x86@kernel.org>
Subject: Re: [PATCH v8 0/2] x86/boot/KASLR: Restrict kernel to be randomized in mirror regions
Date: Fri, 4 Aug 2017 17:59:11 +0800	[thread overview]
Message-ID: <20170804095911.GD32462@localhost.localdomain> (raw)
In-Reply-To: <20170804092241.GH1874@x1>

On Fri, Aug 04, 2017 at 05:22:41PM +0800, Baoquan He wrote:
>On 08/04/17 at 03:52pm, Baoquan He wrote:
>> Sorry, NACK this series, there's error to hang system. Before I just
>> halt system intentionally with error() to check the efi memmap printing,
>> didn't notice this. Checking the cause.
>
>I rebuilt the code or change the one of the replacement back, hang never
>seen again. Not sure if I copied the wrong kernel or any other mistakes.
>Have got a hardware system with efi enabled to try again, see if
>anything wrong will happen. It's really weird. And Chao also is helping
>to try on his side.

Hi Bao,

After testing for 10 times, no problem happened.
Maybe you did something wrong in the first time.

Thanks,
Chao Fan

>
>> 
>> On 08/04/17 at 03:26pm, Baoquan He wrote:
>> > Patch 1/2 is newly added to add efi_memdesc_ptr helper to wrap the
>> > open code which gets the start of efi memmap descriptor and also
>> > explain why it need be done like that, Ingo suggested it. 
>> > 
>> > And also replace several places of the open code with efi_memdesc_ptr
>> > helper.
>> > 
>> > And also use efi_memdesc_ptr in process_efi_entries() which handle efi
>> > mirror issue during KASLR.
>> > 
>> > 
>> > Change:
>> > v7->v8:
>> >     Add efi_memdesc_ptr helper to wrap the open code which gets the
>> >     start of map descriptor according to Ingo's suggestion.
>> > 
>> > v6->v7:
>> >   Ingo pointed out several incorrect line break issues and unclear
>> >   description of patch log. Correct them and rewrite patch log.
>> > 
>> >   And also rewrite the EFI warning message that if EFI memmap is above
>> >   4G in 32bit system since 32bit system can not handle data above 4G at
>> >   kernel decompression stage. This is suggested by Ingo too.
>> > 
>> > v5->v6:
>> >   Code style issue fix according to Kees's comment.
>> > 
>> >   This is based on tip/x86/boot, patch 1,2,3/4 in v5 post has
>> >   been put into tip/x86/boot now.
>> > 
>> > 
>> > 
>> > Baoquan He (2):
>> >   efi: Introduce efi_memdesc_ptr to get pointer to memmap descriptor
>> >   x86/boot/KASLR: Restrict kernel to be randomized in mirror regions
>> > 
>> >  arch/x86/boot/compressed/eboot.c               |  2 +-
>> >  arch/x86/boot/compressed/kaslr.c               | 68 +++++++++++++++++++++++++-
>> >  drivers/firmware/efi/libstub/efi-stub-helper.c |  4 +-
>> >  include/linux/efi.h                            | 19 +++++++
>> >  4 files changed, 88 insertions(+), 5 deletions(-)
>> > 
>> > -- 
>> > 2.5.5
>> > 
>
>