linux-kernel - Re: Xen MMU's requirement to pin pages RO and initial_memory

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: <20110516154132.GA12486@dumpdata.com>
Date:	Mon, 16 May 2011 11:41:32 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	Stefano Stabellini <stefano.stabellini@...citrix.com>
Cc:	"yinghai@...nel.org" <yinghai@...nel.org>,
	"jeremy@...p.org" <jeremy@...p.org>,
	"hpa@...or.com" <hpa@...or.com>,
	"hpa@...ux.intel.com" <hpa@...ux.intel.com>,
	Ian Campbell <Ian.Campbell@...citrix.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"xen-devel@...ts.xensource.com" <xen-devel@...ts.xensource.com>
Subject: Re: Xen MMU's requirement to pin pages RO and initial_memory_mapping.

> They become pagetable pages when:
> 
> - they are explicitly pinned by pin_pagetable_pfn
> 
> - they are hooked into the current pagetable

Ok, so could we use those two calls to trigger the pagetable walk
and mark them RO as appropiate? Which call sites are those? The
xen_set_pgd/xen_set_pud/xen_set_pmd ? Presumarily we don't have
to do that for the PTE's that are already mapped (as
xen_setup_kernel_pagetable, and xen_map_identity_early do this
already).

> Like you wrote, considering that the x86_64 version of
> kernel_physical_mapping_init hooks the pagetable pages into the
> currently used pagetable, it wouldn't be possible to mark the pagetable
> pages RO after init_memory_mapping.

<nods>
--
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/