linux-kernel - Re: [PATCH 3/7] x86, kaslr: find minimum safe relocation position

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <524DF3DA.7060204@zytor.com>
Date:	Thu, 03 Oct 2013 15:46:50 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Kees Cook <keescook@...omium.org>
CC:	LKML <linux-kernel@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>,
	"kernel-hardening@...ts.openwall.com" 
	<kernel-hardening@...ts.openwall.com>,
	Aaron Durbin <adurbin@...gle.com>,
	Eric Northup <digitaleric@...gle.com>,
	Julien Tinnes <jln@...gle.com>, Will Drewry <wad@...gle.com>,
	Mathias Krause <minipli@...glemail.com>,
	Zhang Yanfei <zhangyanfei@...fujitsu.com>
Subject: Re: [PATCH 3/7] x86, kaslr: find minimum safe relocation position

On 10/03/2013 03:43 PM, Kees Cook wrote:
>> This is highly problematic.  The standard protocol is to hoist the
>> initramfs as high as possible in memory, so this may really unacceptably
>> restrict the available range.
> 
> Doesn't this depend on the boot loader's behavior?

It does, but the recommended (and *required* for compatibility with
older kernels) behavior is to hoist as high as possible.

>> It would be better to treat these the same as reserved regions in the
>> e820 map as far as the address space picking algorithm is concerned.
> 
> Could this be considered a future optimization, or do you feel this is
> required even for this first patch series landing?

Yes, I consider it required because of the above.

	-hpa


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/