linux-kernel - Re: [PATCH RFT v8 4/9] fork: Add shadow stack support to clone3()

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: <e8d933e7-b7d9-40ce-99cf-9c9743224fb2@sirena.org.uk>
Date: Fri, 16 Aug 2024 18:06:53 +0100
From: Mark Brown <broonie@...nel.org>
To: Catalin Marinas <catalin.marinas@....com>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>,
	"dietmar.eggemann@....com" <dietmar.eggemann@....com>,
	"juri.lelli@...hat.com" <juri.lelli@...hat.com>,
	"linux-api@...r.kernel.org" <linux-api@...r.kernel.org>,
	"shuah@...nel.org" <shuah@...nel.org>,
	"brauner@...nel.org" <brauner@...nel.org>,
	"dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
	"debug@...osinc.com" <debug@...osinc.com>,
	"mgorman@...e.de" <mgorman@...e.de>,
	"Szabolcs.Nagy@....com" <Szabolcs.Nagy@....com>,
	"fweimer@...hat.com" <fweimer@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"hjl.tools@...il.com" <hjl.tools@...il.com>,
	"rostedt@...dmis.org" <rostedt@...dmis.org>,
	"vincent.guittot@...aro.org" <vincent.guittot@...aro.org>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"vschneid@...hat.com" <vschneid@...hat.com>,
	"kees@...nel.org" <kees@...nel.org>,
	"will@...nel.org" <will@...nel.org>,
	"hpa@...or.com" <hpa@...or.com>,
	"peterz@...radead.org" <peterz@...radead.org>,
	"jannh@...gle.com" <jannh@...gle.com>,
	"bp@...en8.de" <bp@...en8.de>,
	"bsegall@...gle.com" <bsegall@...gle.com>,
	"linux-kselftest@...r.kernel.org" <linux-kselftest@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>
Subject: Re: [PATCH RFT v8 4/9] fork: Add shadow stack support to clone3()

On Fri, Aug 16, 2024 at 04:38:48PM +0100, Catalin Marinas wrote:
> On Fri, Aug 16, 2024 at 02:52:28PM +0000, Edgecombe, Rick P wrote:

> > On the x86 side, we don't have a shadow stack access CMPXCHG. We will have to
> > GUP and do a normal CMPXCHG off of the direct map to handle it fully properly in
> > any case (CLONE_VM or not).

> I guess we could do the same here and for the arm64 gcs_consume_token().
> Basically get_user_page_vma_remote() gives us the page together with the
> vma that you mentioned needs checking. We can then do a cmpxchg directly
> on the page_address(). It's probably faster anyway than doing GUP twice.

There was some complication with get_user_page_vma_remote() while I was
working on an earlier version which meant I didn't use it, though with
adding checking of VMAs perhaps whatever it was isn't such an issue any
more.

Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)