linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: mark.rutland@arm.com (Mark Rutland)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 0/7] arm64: Privileged Access Never using TTBR0_EL1 switching
Date: Fri, 9 Sep 2016 17:31:16 +0100	[thread overview]
Message-ID: <20160909163116.GA10792@leverpostej> (raw)
In-Reply-To: <20160908125123.ypkye5nclsi5vx4f@localhost>

On Thu, Sep 08, 2016 at 01:51:24PM +0100, Catalin Marinas wrote:
> On Wed, Sep 07, 2016 at 04:20:55PM -0700, Kees Cook wrote:
> > On Fri, Sep 2, 2016 at 8:02 AM, Catalin Marinas <catalin.marinas@arm.com> wrote:
> > > This is the second version of the arm64 PAN emulation by disabling
> > > TTBR0_EL1 accesses. The major change from v1 is the use of a thread_info
> > > member to store the real TTBR0_EL1 value. The advantage is slightly
> > > simpler assembler macros for uaccess_enable with the downside that
> > > switch_mm() must always update the saved ttbr0 even if there is no mm
> > > switch.
> > 
> > Is arm64 thread_info attached to the kernel stack? (i.e. is this
> > introducing a valuable target for stack-based attacks?)
> 
> Currently yes, thread_info is on the kernel stack. At some point we'll
> decouple it in a similar way to what x86 are doing/planning.

FWIW, I'm currently working on this (atop of Andy's x86 patches). The
IRQ stack work largely removed out dependence on the stack pointer to
find thread_info, and I have a plan for the remaining places.

There's a fair amount of ground work to do first (e.g. reworking headers
to avoid circular dependencies), but hopefully I'll have something that
I can share soon.

Thanks,
Mark.

  parent reply	other threads:[~2016-09-09 16:31 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-02 15:02 [PATCH v2 0/7] arm64: Privileged Access Never using TTBR0_EL1 switching Catalin Marinas
2016-09-02 15:02 ` [PATCH v2 1/7] arm64: Factor out PAN enabling/disabling into separate uaccess_* macros Catalin Marinas
2016-09-05 15:38   ` Mark Rutland
2016-09-12 14:52     ` Catalin Marinas
2016-09-12 15:09       ` Mark Rutland
2016-09-12 16:26         ` Catalin Marinas
2016-09-02 15:02 ` [PATCH v2 2/7] arm64: Factor out TTBR0_EL1 post-update workaround into a specific asm macro Catalin Marinas
2016-09-05 16:11   ` Mark Rutland
2016-09-02 15:02 ` [PATCH v2 3/7] arm64: Introduce uaccess_{disable, enable} functionality based on TTBR0_EL1 Catalin Marinas
2016-09-05 17:20   ` Mark Rutland
2016-09-06 10:27     ` Catalin Marinas
2016-09-06 10:45       ` Mark Rutland
2016-09-11 13:55         ` [kernel-hardening] " Ard Biesheuvel
2016-09-12  9:32           ` Catalin Marinas
2016-09-09 17:15   ` Catalin Marinas
2016-09-02 15:02 ` [PATCH v2 4/7] arm64: Disable TTBR0_EL1 during normal kernel execution Catalin Marinas
2016-09-06 17:31   ` Mark Rutland
2016-09-02 15:02 ` [PATCH v2 5/7] arm64: Handle faults caused by inadvertent user access with PAN enabled Catalin Marinas
2016-09-02 15:02 ` [PATCH v2 6/7] arm64: xen: Enable user access before a privcmd hvc call Catalin Marinas
2016-09-02 15:02 ` [PATCH v2 7/7] arm64: Enable CONFIG_ARM64_TTBR0_PAN Catalin Marinas
2016-09-02 15:47   ` Mark Rutland
2016-09-07 23:20 ` [PATCH v2 0/7] arm64: Privileged Access Never using TTBR0_EL1 switching Kees Cook
2016-09-08 12:51   ` Catalin Marinas
2016-09-08 15:50     ` Kees Cook
2016-09-09 16:31     ` Mark Rutland [this message]
2016-09-09 18:24       ` Kees Cook
2016-09-09 23:40 ` [kernel-hardening] " David Brown
2016-09-10  9:51 ` Catalin Marinas
2016-09-10 10:56   ` Ard Biesheuvel
2016-09-11 12:16     ` Catalin Marinas

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20160909163116.GA10792@leverpostej \
    --to=mark.rutland@arm.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).