linux-kernel - Re: [tip:x86/asm] x86/asm/entry: Add user_mode_ignore

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: <CALCETrU4r1F99BzTS68MeYN0p6v+qem5_LnC+2H4GVztrSu+Zg@mail.gmail.com>
Date:	Tue, 24 Mar 2015 12:46:42 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	Brad Spengler <spender@...ecurity.net>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Borislav Petkov <bp@...en8.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Lutomirski <luto@...nel.org>,
	Denys Vlasenko <dvlasenk@...hat.com>,
	"linux-tip-commits@...r.kernel.org" 
	<linux-tip-commits@...r.kernel.org>
Subject: Re: [tip:x86/asm] x86/asm/entry: Add user_mode_ignore_vm86()

On Tue, Mar 24, 2015 at 12:44 PM, Ingo Molnar <mingo@...nel.org> wrote:
>
> * Andy Lutomirski <luto@...capital.net> wrote:
>
>> On Mon, Mar 23, 2015 at 5:26 AM, tip-bot for Andy Lutomirski
>> <tipbot@...or.com> wrote:
>> > Commit-ID:  a67e7277d01ccfd39b0db5a198c2643cc19dd79c
>> > Gitweb:     http://git.kernel.org/tip/a67e7277d01ccfd39b0db5a198c2643cc19dd79c
>> > Author:     Andy Lutomirski <luto@...nel.org>
>> > AuthorDate: Wed, 18 Mar 2015 18:33:29 -0700
>> > Committer:  Ingo Molnar <mingo@...nel.org>
>> > CommitDate: Mon, 23 Mar 2015 11:13:36 +0100
>> >
>> > x86/asm/entry: Add user_mode_ignore_vm86()
>> >
>> > user_mode() is dangerous and user_mode_vm() has a confusing name.
>> >
>> > Add user_mode_ignore_vm86() (equivalent to current user_mode()).
>> > We'll change the small number of legitimate users of user_mode()
>> > to user_mode_ignore_vm86().
>> >
>> > Inspired by grsec, although this works rather differently.
>>
>> Ingo, does this mean that you changed your mind or do you still want
>> a patch to delete user_mode_ignore_vm86 and just use user_mode
>> everywhere instead?
>
> Would be still nice to have it as an add on patch, if you agree with
> my arguments.

Given that there are only a very small number of callers left and
they're all Obviously Correct (tm), I'm not too worried about it.
Maybe if we kill off __copy_to_user, I'll be inspired to kill off
user_mode_ignore_vm86 as well :)

--Andy

>
> I picked up your series as-is because it's correct and because it
> already improves things a lot in this area.
>
> Thanks,
>
>         Ingo



-- 
Andy Lutomirski
AMA Capital Management, LLC
--
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/