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: <56E09E8B.1010909@eng.utah.edu>
Date:	Wed, 9 Mar 2016 15:07:07 -0700
From:	Scotty Bauer <sbauer@....utah.edu>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org, kernel-hardening@...ts.openwall.com,
	x86@...nel.org, wmealing@...hat.com, ak@...ux.intel.com,
	luto@...capital.net, Abhiram Balasubramanian <abhiram@...utah.edu>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH v3 1/3] SROP Mitigation: Architecture independent code for
 signal cookies



On 03/09/2016 01:32 AM, Ingo Molnar wrote:
> 
> * Scott Bauer <sbauer@....utah.edu> wrote:
> 
>> This patch adds a per-process secret to the task struct which
>> will be used during signal delivery and during a sigreturn.
>> Also, logic is added in signal.c to generate, place, extract,
>> clear and verify the signal cookie.
> 
>>  	/*
>> +	 * Canary value for signal frames placed on user stack.
>> +	 * This helps mitigate "Signal Return oriented program"
>> +	 * exploits in userland.
>> +	 */
>> +	unsigned long sig_cookie;
> 
> Could you please add a high level description in Documentation
> that explains the attack and the way how this mitigation code
> prevents that kind of attack?
> 
> Also, the first changelogs should contain more high level
> description as well. For example, what does the 'verification'
> of the signal cookie mean, and how does it prevent an SROP
> attempt?
> 
> All of these patches seem to assume that people reading this code
> know what SROP is and how we defend against it - that is not so.
> 
> Thanks,
> 
> 	Ingo
> 


I'm going to submit v4 to fix some nits where I'll include the explanation
and a change log, I apologize for not doing that here. In the meantime if
you don't mind visiting a link I included a brief explanation on previous
versions of the patch set.


https://lkml.org/lkml/2016/2/6/166

Thanks

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ