linux-kernel - Re: On the correctness of dbe3ed1c078c193be34326728d494c5c4bc115e2

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: <522364AA.9050506@zytor.com>
Date:	Sun, 01 Sep 2013 09:00:42 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
CC:	Randy Dunlap <rdunlap@...otime.net>,
	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Arjan van de Ven <arjan@...ux.intel.com>
Subject: Re: On the correctness of dbe3ed1c078c193be34326728d494c5c4bc115e2

On 09/01/2013 08:58 AM, Linus Torvalds wrote:
> On Sun, Sep 1, 2013 at 5:20 AM, H. Peter Anvin <hpa@...or.com> wrote:
>>
>> This has the end result that we treat a user space instruction which
>> touches a privileged data structure that then page faults (e.g. a
>> segment load which causes #PF on the GDT) as a user-space fault.
>>
>> This seems very wrong to me, since such a #PF would indicate a serious
>> error in the kernel.
> 
> Not necessarily. Don't we basically do exactly that for the F00F bug
> workaround, for example?
> 

We do, but only after matching on an exact address (is_f00f_bug()).
Note also that is_f00f_bug() isn't conditional on PF_USER.

	-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/