linux-kernel - Re: Regression: Requiring CAP_SYS_ADMIN for /proc/<pid>/pagemap causes application-level breakage

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: <20150429213744.GA12552@node.dhcp.inet.fi>
Date:	Thu, 30 Apr 2015 00:37:44 +0300
From:	"Kirill A. Shutemov" <kirill@...temov.name>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Konstantin Khlebnikov <koct9i@...il.com>,
	Mark Williamson <mwilliamson@...o-software.com>,
	Mark Seaborn <mseaborn@...omium.org>,
	kernel list <linux-kernel@...r.kernel.org>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Pavel Emelyanov <xemul@...allels.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Andy Lutomirski <luto@...capital.net>,
	Linux API <linux-api@...r.kernel.org>,
	Finn Grimwood <fgrimwood@...o-software.com>,
	Daniel James <djames@...o-software.com>,
	Cyrill Gorcunov <gorcunov@...nvz.org>
Subject: Re: Regression: Requiring CAP_SYS_ADMIN for /proc/<pid>/pagemap
 causes application-level breakage

On Wed, Apr 29, 2015 at 02:18:49PM -0700, Linus Torvalds wrote:
> On Wed, Apr 29, 2015 at 2:05 PM, Kirill A. Shutemov
> <kirill@...temov.name> wrote:
> >
> > This sounds too ugly to be exposed it as ABI.
> 
> Oh, pretty it ain't. However, regressions in many ways are worse. If
> it makes it possible to not regress...

One idea is to extend kcmp(2) with KCMP_PAGE. idx1 and idx2 are virtual
addresses in two processes. It returns 0 if addresses points to the same
page and 3 otherwise.

Would it be enough for the use case?

I guess it could be too slow to check one page a time...

Invent new kcmpv(2)? ;)

-- 
 Kirill A. Shutemov
--
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/