linux-kernel - Re: [PATCH v3 1/2] x86_64,signal: Fix SS handling for signals delivered to 64-bit programs

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]

Date:	Fri, 20 Mar 2015 12:43:14 +0100
From:	Denys Vlasenko <vda.linux@...glemail.com>
To:	Cyrill Gorcunov <gorcunov@...il.com>
Cc:	Andy Lutomirski <luto@...capital.net>,
	Pavel Emelyanov <xemul@...allels.com>,
	Oleg Nesterov <oleg@...hat.com>,
	Andrey Wagin <avagin@...il.com>,
	Andy Lutomirski <luto@...nel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Andi Kleen <andi@...stfloor.org>,
	"H. Peter Anvin" <hpa@...or.com>,
	Al Viro <viro@...iv.linux.org.uk>, X86 ML <x86@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Borislav Petkov <bp@...en8.de>,
	Pavel Emelyanov <xemul@...nvz.org>
Subject: Re: [PATCH v3 1/2] x86_64,signal: Fix SS handling for signals
 delivered to 64-bit programs

On Thu, Mar 19, 2015 at 8:35 AM, Cyrill Gorcunov <gorcunov@...il.com> wrote:
> On Wed, Mar 18, 2015 at 03:03:27PM -0700, Andy Lutomirski wrote:
>> I don't have a great idea for how to work around this, unfortunately.
>> Ideally we'd increment some kind of version counter or use an
>> extension mechanism rather than shoving ss into a field that used to
>> be padding.
>
> fwiw currently we're passing zero in this __pad0 (replying to your
> previous email, so we can workaround in the kernel assuming zero
> as a special case, not that good but better than nothing).

Special-casing zero sounds not that bad to me.
It can be removed after a few years - just don't forget
to document it in a good comment: why we have special
case? What software required it?
In which version of that software the need to have this hack
was eliminated?
--
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/