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* Re: [PATCH v3] gpio: pl061: Fix the issue failed to register the ACPI interrtupion
From: Linus Walleij @ 2019-08-20  7:12 UTC (permalink / raw)
  To: Andy Shevchenko, Thierry Reding
  Cc: Salil Mehta, jinying, Tangkunshan, Liguozhu (Kenneth), John Garry,
	Rafael J. Wysocki, Linux Kernel Mailing List, Wei Xu, Linuxarm,
	open list:GPIO SUBSYSTEM, Shameerali Kolothum Thodi, huangdaode,
	Jonathan Cameron, Shiju Jose, Mika Westerberg, Zhangyi ac,
	linux-arm Mailing List, Len Brown
In-Reply-To: <CAHp75Vct3qtR5bDF6iALmduKEEq+gNL-btmzQVuWq_hYsmxKhw@mail.gmail.com>

On Mon, Aug 19, 2019 at 5:07 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:

> The proper fix is to revert the culprit since we call
> acpi_gpiochip_request_interrupts() for all controllers.
> Linus, please re-do the approach with IRQ handling,

Exactly what do you refer to when you want me to
"re-do the approach for IRQ handling"? Do you mean
this driver or are you referring to:

commit e0d89728981393b7d694bd3419b7794b9882c92d
Author: Thierry Reding <treding@nvidia.com>
Date:   Tue Nov 7 19:15:54 2017 +0100

    gpio: Implement tighter IRQ chip integration

    Currently GPIO drivers are required to add the GPIO chip and its
    corresponding IRQ chip separately, which can result in a lot of
    boilerplate. Use the newly introduced struct gpio_irq_chip, embedded in
    struct gpio_chip, that drivers can fill in if they want the GPIO core
    to automatically register the IRQ chip associated with a GPIO chip.

    Signed-off-by: Thierry Reding <treding@nvidia.com>
    Acked-by: Grygorii Strashko <grygorii.strashko@ti.com>
    Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

The new API introduced by this patch is what I am trying to switch
everything over to, because the forked paths inside of gpiolib
is causing me a maintenance headache and also increasing
the footprint of the library.

>  it seems broadly
> regress with ACPI enabled platforms.

It only becomes a problem if the platform uses ACPI right?
But it's a problem if I can't really tell if a driver is using
ACPI or not, there is no sign in the pl061 driver that it would
be used on ACPI systems until now, so how do I design
for it?

The problem comes from the problem/mess I am trying to
clean up in the first place. So if the new way of registering GPIO
irqchips is not working for ACPI, then we have to fix that instead
of reverting all attempts to use the new API IMO.

Yours,
Linus Walleij

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* Re: [PATCH v4 02/10] clk: sunxi-ng: Mark AR100 clocks as critical
From: Maxime Ripard @ 2019-08-20  7:11 UTC (permalink / raw)
  To: Samuel Holland
  Cc: Mark Rutland, devicetree, linux-sunxi, Stephen Boyd,
	Michael Turquette, Jassi Brar, linux-kernel, Chen-Yu Tsai,
	Rob Herring, Corentin Labbe, linux-clk, linux-arm-kernel
In-Reply-To: <20190820032311.6506-3-samuel@sholland.org>


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Hi,

On Mon, Aug 19, 2019 at 10:23:03PM -0500, Samuel Holland wrote:
> On sun8i, sun9i, and sun50i SoCs, system suspend/resume support requires
> firmware running on the AR100 coprocessor (the "SCP"). Such firmware can
> provide additional features, such as thermal monitoring and poweron/off
> support for boards without a PMIC.
>
> Since the AR100 may be running critical firmware, even if Linux does not
> know about it or directly interact with it (all requests may go through
> an intermediary interface such as PSCI), Linux must not turn off its
> clock.
>
> At this time, such power management firmware only exists for the A64 and
> H5 SoCs.  However, it makes sense to take care of all CCU drivers now
> for consistency, and to ease the transition in the future once firmware
> is ported to the other SoCs.
>
> Leaving the clock running is safe even if no firmware is present, since
> the AR100 stays in reset by default. In most cases, the AR100 clock is
> kept enabled by Linux anyway, since it is the parent of all APB0 bus
> peripherals. This change only prevents Linux from turning off the AR100
> clock in the rare case that no peripherals are in use.
>
> Signed-off-by: Samuel Holland <samuel@sholland.org>

So I'm not really sure where you want to go with this.

That clock is only useful where you're having a firmware running on
the AR100, and that firmware would have a device tree node of its own,
where we could list the clocks needed for the firmware to keep
running, if it ever runs. If the driver has not been compiled in /
loaded, then we don't care either.

But more fundamentally, if we're going to use SCPI, then those clocks
will not be handled by that driver anyway, but by the firmware, right?

So I'm not really sure that we should do it statically this way, and
that we should do it at all.

Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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* Re: [PATCH v2 00/17] Arm SMMU refactoring
From: Will Deacon @ 2019-08-20  7:04 UTC (permalink / raw)
  To: Robin Murphy
  Cc: robdclark, joro, bjorn.andersson, iommu, vivek.gautam, jcrouse,
	gregory.clement, linux-arm-kernel
In-Reply-To: <d8a47e62-0768-7ae2-f2fc-53b5b2b24685@arm.com>

On Mon, Aug 19, 2019 at 07:10:45PM +0100, Robin Murphy wrote:
> On 19/08/2019 16:56, Will Deacon wrote:
> > On Thu, Aug 15, 2019 at 07:37:20PM +0100, Robin Murphy wrote:
> > > v1 for context: https://patchwork.kernel.org/cover/11087347/
> > > 
> > > Here's a quick v2 attempting to address all the minor comments; I've
> > > tweaked a whole bunch of names, added some verbosity in macros and
> > > comments for clarity, and rejigged arm_smmu_impl_init() for a bit more
> > > structure. The (new) patches #1 and #2 are up front as conceptual fixes,
> > > although they're not actually critical - it turns out to be more of an
> > > embarrassment than a real problem in practice.
> > 
> > Thanks, I'll pick this up and send to Joerg later this week.
> 
> Oops, I've just noticed that the io-64-nonatomic-hi-lo.h include also needs
> to move to arm-smmu.h in #14 to avoid breaking 32-bit builds. I've pushed
> out an updated branch (along with the static fixes for good measure) - let
> me know if you'd like a resend of the patches.

Can you just send a patch on top instead, please? I'd prefer not to rebase
things unless we really need to, and I've already pushed this stuff to
for-joerg/arm-smmu/refactoring.

Thanks,

Will

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* RE: [PATCH v3] scsi: ufs: fix broken hba->outstanding_tasks
From: Avri Altman @ 2019-08-20  6:59 UTC (permalink / raw)
  To: Stanley Chu, linux-scsi@vger.kernel.org,
	martin.petersen@oracle.com, alim.akhtar@samsung.com,
	pedrom.sousa@synopsys.com
  Cc: marc.w.gonzalez@free.fr, andy.teng@mediatek.com,
	chun-hung.wu@mediatek.com, kuohong.wang@mediatek.com,
	evgreen@chromium.org, linux-mediatek@lists.infradead.org,
	peter.wang@mediatek.com, matthias.bgg@gmail.com,
	linux-arm-kernel@lists.infradead.org, beanhuo@micron.com
In-Reply-To: <1566222208-19890-1-git-send-email-stanley.chu@mediatek.com>

> 
> Currently bits in hba->outstanding_tasks are cleared only after their
> corresponding task management commands are successfully done by
> __ufshcd_issue_tm_cmd().
> 
> If timeout happens in a task management command, its corresponding
> bit in hba->outstanding_tasks will not be cleared until next task
> management command with the same tag used successfully finishes.
> 
> This is wrong and can lead to some issues, like power issue.
> For example, ufshcd_release() and ufshcd_gate_work() will do nothing
> if hba->outstanding_tasks is not zero even if both UFS host and devices
> are actually idle.
> 
> Solution is referried from error handling of device commands: bits in
> hba->outstanding_tasks shall be cleared regardless of their execution
> results.
> 
> Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
> Signed-off-by: Chun-Hung Wu <chun-hung.wu@mediatek.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>


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* Re: [kbuild-all] [PATCH v3 4/5] arm64: perf: Enable pmu counter direct access for perf event on armv8
From: Philip Li @ 2019-08-20  6:49 UTC (permalink / raw)
  To: Raphael Gault
  Cc: mark.rutland, kbuild test robot, peterz, catalin.marinas,
	will.deacon, linux-kernel, acme, mingo, kbuild-all,
	linux-arm-kernel, raph.gault+kdev
In-Reply-To: <a41e1a4b-b082-725a-b24e-9c92f66d174a@arm.com>

On Mon, Aug 19, 2019 at 08:59:33AM +0100, Raphael Gault wrote:
> Hi,
> 
> On 8/18/19 1:37 PM, kbuild test robot wrote:
> > Hi Raphael,
> > 
> > Thank you for the patch! Yet something to improve:
> > 
> > [auto build test ERROR on linus/master]
> > [cannot apply to v5.3-rc4 next-20190816]
> > [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> 
> This patchset was based on linux-next/master and note linus
thanks for the input, we will look for how to find better base to test.

> 
> Thanks,
> 
> -- 
> Raphael Gault
> _______________________________________________
> kbuild-all mailing list
> kbuild-all@lists.01.org
> https://lists.01.org/mailman/listinfo/kbuild-all

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* RE: [PATCH V5 0/3] perf: imx8_ddr_perf: add AXI ID filter
From: Joakim Zhang @ 2019-08-20  6:37 UTC (permalink / raw)
  To: robin.murphy@arm.com, will@kernel.org, mark.rutland@arm.com
  Cc: Frank Li, dl-linux-imx, linux-arm-kernel@lists.infradead.org
In-Reply-To: <VI1PR04MB4910CE0F28AFD6E278EE106088D70@VI1PR04MB4910.eurprd04.prod.outlook.com>


Kindly ping...

Best Regards,
Joakim Zhang

> -----Original Message-----
> From: Frank Li
> Sent: 2019年8月8日 21:56
> To: Joakim Zhang <qiangqing.zhang@nxp.com>; robin.murphy@arm.com;
> will@kernel.org; mark.rutland@arm.com
> Cc: linux-arm-kernel@lists.infradead.org; dl-linux-imx <linux-imx@nxp.com>
> Subject: RE: [PATCH V5 0/3] perf: imx8_ddr_perf: add AXI ID filter
> 
> 
> 
> > -----Original Message-----
> > From: Joakim Zhang
> > Sent: Thursday, August 8, 2019 1:45 AM
> > To: robin.murphy@arm.com; will@kernel.org; mark.rutland@arm.com
> > Cc: Frank Li <frank.li@nxp.com>; linux-arm-kernel@lists.infradead.org;
> > dl-linux- imx <linux-imx@nxp.com>; Joakim Zhang
> > <qiangqing.zhang@nxp.com>
> > Subject: [PATCH V5 0/3] perf: imx8_ddr_perf: add AXI ID filter
> >
> > Add AXI ID filter for imx8m ddr perf.
> >
> > Joakim Zhang (3):
> >   perf: imx8_ddr_perf: add AXI ID filter support
> >   Documentation: admin-guide: perf: add i.MX8 ddr pmu user doc
> >   MAINTAINERS: add imx8 ddr perf admin-guide maintainer information
> >
> >  Documentation/admin-guide/perf/imx-ddr.rst | 30 +++++++++++
> >  MAINTAINERS                                |  1 +
> >  drivers/perf/fsl_imx8_ddr_perf.c           | 63
> +++++++++++++++++++++-
> >  3 files changed, 92 insertions(+), 2 deletions(-)  create mode 100644
> > Documentation/admin-guide/perf/imx-ddr.rst
> >
> Acked-by: Frank Li <Frank.li@nxp.com>
> 
> > --
> > 2.17.1

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* Re: [PATCH] ASoC: uniphier: Fix double reset assersion when transitioning to suspend state
From: Uwe Kleine-König @ 2019-08-20  6:34 UTC (permalink / raw)
  To: Kunihiko Hayashi
  Cc: alsa-devel, Masami Hiramatsu, Liam Girdwood, linux-kernel,
	Jassi Brar, Mark Brown, linux-arm-kernel
In-Reply-To: <1566281764-14059-1-git-send-email-hayashi.kunihiko@socionext.com>

Hello,

just noticed while reading through my linux-arm-kernel folder:

$Subject ~= s/assersion/assertion/

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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* [PATCH] ASoC: uniphier: Fix double reset assersion when transitioning to suspend state
From: Kunihiko Hayashi @ 2019-08-20  6:16 UTC (permalink / raw)
  To: alsa-devel, Mark Brown, Liam Girdwood
  Cc: Jassi Brar, Kunihiko Hayashi, linux-arm-kernel, Masami Hiramatsu,
	linux-kernel

When transitioning to supend state, uniphier_aio_dai_suspend() is called
and asserts reset lines and disables clocks.

However, if there are two or more DAIs, uniphier_aio_dai_suspend() are
called multiple times, and double reset assersion will cause.

This patch defines the counter that has the number of DAIs at first, and
whenever uniphier_aio_dai_suspend() are called, it decrements the
counter. And only if the counter is zero, it asserts reset lines and
disables clocks.

In the same way, uniphier_aio_dai_resume() are called, it increments the
counter after deasserting reset lines and enabling clocks.

Fixes: 139a34200233 ("ASoC: uniphier: add support for UniPhier AIO CPU DAI driver")
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
---
 sound/soc/uniphier/aio-cpu.c | 31 +++++++++++++++++++++----------
 sound/soc/uniphier/aio.h     |  1 +
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/sound/soc/uniphier/aio-cpu.c b/sound/soc/uniphier/aio-cpu.c
index ee90e6c..2ae582a 100644
--- a/sound/soc/uniphier/aio-cpu.c
+++ b/sound/soc/uniphier/aio-cpu.c
@@ -424,8 +424,11 @@ int uniphier_aio_dai_suspend(struct snd_soc_dai *dai)
 {
 	struct uniphier_aio *aio = uniphier_priv(dai);
 
-	reset_control_assert(aio->chip->rst);
-	clk_disable_unprepare(aio->chip->clk);
+	aio->chip->num_wup_aios--;
+	if (!aio->chip->num_wup_aios) {
+		reset_control_assert(aio->chip->rst);
+		clk_disable_unprepare(aio->chip->clk);
+	}
 
 	return 0;
 }
@@ -439,13 +442,15 @@ int uniphier_aio_dai_resume(struct snd_soc_dai *dai)
 	if (!aio->chip->active)
 		return 0;
 
-	ret = clk_prepare_enable(aio->chip->clk);
-	if (ret)
-		return ret;
+	if (!aio->chip->num_wup_aios) {
+		ret = clk_prepare_enable(aio->chip->clk);
+		if (ret)
+			return ret;
 
-	ret = reset_control_deassert(aio->chip->rst);
-	if (ret)
-		goto err_out_clock;
+		ret = reset_control_deassert(aio->chip->rst);
+		if (ret)
+			goto err_out_clock;
+	}
 
 	aio_iecout_set_enable(aio->chip, true);
 	aio_chip_init(aio->chip);
@@ -458,7 +463,7 @@ int uniphier_aio_dai_resume(struct snd_soc_dai *dai)
 
 		ret = aio_init(sub);
 		if (ret)
-			goto err_out_clock;
+			goto err_out_reset;
 
 		if (!sub->setting)
 			continue;
@@ -466,11 +471,16 @@ int uniphier_aio_dai_resume(struct snd_soc_dai *dai)
 		aio_port_reset(sub);
 		aio_src_reset(sub);
 	}
+	aio->chip->num_wup_aios++;
 
 	return 0;
 
+err_out_reset:
+	if (!aio->chip->num_wup_aios)
+		reset_control_assert(aio->chip->rst);
 err_out_clock:
-	clk_disable_unprepare(aio->chip->clk);
+	if (!aio->chip->num_wup_aios)
+		clk_disable_unprepare(aio->chip->clk);
 
 	return ret;
 }
@@ -619,6 +629,7 @@ int uniphier_aio_probe(struct platform_device *pdev)
 		return PTR_ERR(chip->rst);
 
 	chip->num_aios = chip->chip_spec->num_dais;
+	chip->num_wup_aios = chip->num_aios;
 	chip->aios = devm_kcalloc(dev,
 				  chip->num_aios, sizeof(struct uniphier_aio),
 				  GFP_KERNEL);
diff --git a/sound/soc/uniphier/aio.h b/sound/soc/uniphier/aio.h
index ca6ccba..a7ff7e5 100644
--- a/sound/soc/uniphier/aio.h
+++ b/sound/soc/uniphier/aio.h
@@ -285,6 +285,7 @@ struct uniphier_aio_chip {
 
 	struct uniphier_aio *aios;
 	int num_aios;
+	int num_wup_aios;
 	struct uniphier_aio_pll *plls;
 	int num_plls;
 
-- 
2.7.4


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* [PATCH v4] arm64: dts: ls1088a: fix gpio node
From: Hui Song @ 2019-08-20  5:54 UTC (permalink / raw)
  To: Shawn Guo, Li Yang, Rob Herring, Mark Rutland, Linus Walleij,
	Bartosz Golaszewski
  Cc: devicetree, Song Hui, linux-kernel, linux-arm-kernel, linux-gpio

From: Song Hui <hui.song_1@nxp.com>

add ls1088a gpio specify compatible.

Signed-off-by: Song Hui <hui.song_1@nxp.com>
---
Changes in v4:
	- update the patch description.
Changes in v3:
	- delete the attribute of little-endian.
Changes in v2:
	- update the subject.
 

diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1088a.dtsi b/arch/arm64/boot/dts/freescale/fsl-ls1088a.dtsi
index dfbead4..ff669c8 100644
--- a/arch/arm64/boot/dts/freescale/fsl-ls1088a.dtsi
+++ b/arch/arm64/boot/dts/freescale/fsl-ls1088a.dtsi
@@ -269,7 +269,7 @@
 		};
 
 		gpio0: gpio@2300000 {
-			compatible = "fsl,qoriq-gpio";
+			compatible = "fsl,ls1088a-gpio", "fsl,qoriq-gpio";
 			reg = <0x0 0x2300000 0x0 0x10000>;
 			interrupts = <0 36 IRQ_TYPE_LEVEL_HIGH>;
 			little-endian;
@@ -280,7 +280,7 @@
 		};
 
 		gpio1: gpio@2310000 {
-			compatible = "fsl,qoriq-gpio";
+			compatible = "fsl,ls1088a-gpio", "fsl,qoriq-gpio";
 			reg = <0x0 0x2310000 0x0 0x10000>;
 			interrupts = <0 36 IRQ_TYPE_LEVEL_HIGH>;
 			little-endian;
@@ -291,7 +291,7 @@
 		};
 
 		gpio2: gpio@2320000 {
-			compatible = "fsl,qoriq-gpio";
+			compatible = "fsl,ls1088a-gpio", "fsl,qoriq-gpio";
 			reg = <0x0 0x2320000 0x0 0x10000>;
 			interrupts = <0 37 IRQ_TYPE_LEVEL_HIGH>;
 			little-endian;
@@ -302,7 +302,7 @@
 		};
 
 		gpio3: gpio@2330000 {
-			compatible = "fsl,qoriq-gpio";
+			compatible = "fsl,ls1088a-gpio", "fsl,qoriq-gpio";
 			reg = <0x0 0x2330000 0x0 0x10000>;
 			interrupts = <0 37 IRQ_TYPE_LEVEL_HIGH>;
 			little-endian;
-- 
2.9.5


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* Re: [PATCH] arm64: fix CONFIG_KASAN_SW_TAGS && CONFIG_KASAN_INLINE (was: Re: [PATCH V5 03/12] arm64: kasan: Switch to using) KASAN_SHADOW_OFFSET
From: Bhupesh Sharma @ 2019-08-20  6:02 UTC (permalink / raw)
  To: Will Deacon
  Cc: Mark Rutland, Christoph von Recklinghausen, Ard Biesheuvel,
	Catalin Marinas, Steve Capper, kasan-dev, glider, Dmitry Vyukov,
	maz, Andrey Ryabinin, linux-arm-kernel
In-Reply-To: <20190815120908.kboyqfnr2fivuva4@willie-the-truck>

On Thu, Aug 15, 2019 at 5:39 PM Will Deacon <will@kernel.org> wrote:
>
> [+more kasan people and the kasan-dev list]
>
> On Wed, Aug 14, 2019 at 05:03:24PM +0100, Mark Rutland wrote:
> > On Wed, Aug 14, 2019 at 04:57:11PM +0100, Will Deacon wrote:
> > > On Wed, Aug 14, 2019 at 04:20:18PM +0100, Mark Rutland wrote:
> > > > On Wed, Aug 07, 2019 at 04:55:15PM +0100, Steve Capper wrote:
> > > > > diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
> > > > > index b2400f9c1213..2b7db0d41498 100644
> > > > > --- a/arch/arm64/Makefile
> > > > > +++ b/arch/arm64/Makefile
> > > > > @@ -126,14 +126,6 @@ KBUILD_CFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
> > > > >  KBUILD_CPPFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
> > > > >  KBUILD_AFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
> > > > >
> > > > > -# KASAN_SHADOW_OFFSET = VA_START + (1 << (VA_BITS - KASAN_SHADOW_SCALE_SHIFT))
> > > > > -#                               - (1 << (64 - KASAN_SHADOW_SCALE_SHIFT))
> > > > > -# in 32-bit arithmetic
> > > > > -KASAN_SHADOW_OFFSET := $(shell printf "0x%08x00000000\n" $$(( \
> > > > > -       (0xffffffff & (-1 << ($(CONFIG_ARM64_VA_BITS) - 1 - 32))) \
> > > > > -       + (1 << ($(CONFIG_ARM64_VA_BITS) - 32 - $(KASAN_SHADOW_SCALE_SHIFT))) \
> > > > > -       - (1 << (64 - 32 - $(KASAN_SHADOW_SCALE_SHIFT))) )) )
> > > > > -
> > > > >  export TEXT_OFFSET GZFLAGS
> > > > >
> > > > >  core-y         += arch/arm64/kernel/ arch/arm64/mm/
> > > >
> > > > I've just spotted this breaks build using CONFIG_KASAN_SW_TAGS &&
> > > > CONFIG_KASAN_INLINE, as scripts/Makefile.kasan only propagates
> > > > CONFIG_KASAN_SHADOW_OFFSET into KASAN_SHADOW_OFFSET when
> > > > CONFIG_KASAN_GENERIC is selected, but consumes KASAN_SHADOW_OFFSET
> > > > regardless.
> > > >
> > > > I think that's by accident rather than by design, but to
> > > > minimize/localize the fixup, how about the below? I can send a cleanup
> > > > patch for scripts/Makefile.kasan later.
> > >
> > > How much work is that? I've dropped this stuff from -next for now, so we
> > > have time to fix it properly as long as it's not going to take weeks.
> >
> > I wrote it first, so no effort; patch below.
>
> The patch looks fine to me, but I'd like an Ack from one of the KASAN
> folks before I queue this via the arm64 tree (where support for 52-bit
> virtual addressing in the kernel [1] depends on this being fixed).
>
> Patch is quoted below. Please can somebody take a look?

I tested this on my hpe and apm arm64 hardware boxes and the issue I
reported via <http://lists.infradead.org/pipermail/linux-arm-kernel/2019-August/673424.html>
seem fixed, so:

Tested-by: Bhupesh Sharma <bhsharma@redhat.com>

Thanks,
Bhupesh

> [1] https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/log/?h=for-next/52-bit-kva
>
> > From ecdf60051a850f817d98f84ae9011afa2311b8f1 Mon Sep 17 00:00:00 2001
> > From: Mark Rutland <mark.rutland@arm.com>
> > Date: Wed, 14 Aug 2019 15:31:57 +0100
> > Subject: [PATCH] kasan/arm64: fix CONFIG_KASAN_SW_TAGS && KASAN_INLINE
> >
> > The generic Makefile.kasan propagates CONFIG_KASAN_SHADOW_OFFSET into
> > KASAN_SHADOW_OFFSET, but only does so for CONFIG_KASAN_GENERIC.
> >
> > Since commit:
> >
> >   6bd1d0be0e97936d ("arm64: kasan: Switch to using KASAN_SHADOW_OFFSET")
> >
> > ... arm64 defines CONFIG_KASAN_SHADOW_OFFSET in Kconfig rather than
> > defining KASAN_SHADOW_OFFSET in a Makefile. Thus, if
> > CONFIG_KASAN_SW_TAGS && KASAN_INLINE are selected, we get build time
> > splats due to KASAN_SHADOW_OFFSET not being set:
> >
> > | [mark@lakrids:~/src/linux]% usellvm 8.0.1 usekorg 8.1.0  make ARCH=arm64 CROSS_COMPILE=aarch64-linux- CC=clang
> > | scripts/kconfig/conf  --syncconfig Kconfig
> > |   CC      scripts/mod/empty.o
> > | clang (LLVM option parsing): for the -hwasan-mapping-offset option: '' value invalid for uint argument!
> > | scripts/Makefile.build:273: recipe for target 'scripts/mod/empty.o' failed
> > | make[1]: *** [scripts/mod/empty.o] Error 1
> > | Makefile:1123: recipe for target 'prepare0' failed
> > | make: *** [prepare0] Error 2
> >
> > Let's fix this by always propagating CONFIG_KASAN_SHADOW_OFFSET into
> > KASAN_SHADOW_OFFSET if CONFIG_KASAN is selected, moving the existing
> > common definition of +CFLAGS_KASAN_NOSANITIZE to the top of
> > Makefile.kasan.
> >
> > Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> > Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
> > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > Cc: Steve Capper <steve.capper@arm.com>
> > Cc: Will Deacon <will@kernel.org>
> > ---
> >  scripts/Makefile.kasan | 11 +++++------
> >  1 file changed, 5 insertions(+), 6 deletions(-)
> >
> > diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
> > index 6410bd22fe38..03757cc60e06 100644
> > --- a/scripts/Makefile.kasan
> > +++ b/scripts/Makefile.kasan
> > @@ -1,4 +1,9 @@
> >  # SPDX-License-Identifier: GPL-2.0
> > +ifdef CONFIG_KASAN
> > +CFLAGS_KASAN_NOSANITIZE := -fno-builtin
> > +KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
> > +endif
> > +
> >  ifdef CONFIG_KASAN_GENERIC
> >
> >  ifdef CONFIG_KASAN_INLINE
> > @@ -7,8 +12,6 @@ else
> >       call_threshold := 0
> >  endif
> >
> > -KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
> > -
> >  CFLAGS_KASAN_MINIMAL := -fsanitize=kernel-address
> >
> >  cc-param = $(call cc-option, -mllvm -$(1), $(call cc-option, --param $(1)))
> > @@ -45,7 +48,3 @@ CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
> >               $(instrumentation_flags)
> >
> >  endif # CONFIG_KASAN_SW_TAGS
> > -
> > -ifdef CONFIG_KASAN
> > -CFLAGS_KASAN_NOSANITIZE := -fno-builtin
> > -endif
> > --
> > 2.11.0
> >

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* RE: [PATCH] pwm: mxs: use devm_platform_ioremap_resource() to simplify code
From: Anson Huang @ 2019-08-20  5:56 UTC (permalink / raw)
  To: Aisheng Dong, thierry.reding@gmail.com, shawnguo@kernel.org,
	s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com,
	linux-pwm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
  Cc: dl-linux-imx
In-Reply-To: <AM0PR04MB42116F0753C9C6A619A2D8EC80C80@AM0PR04MB4211.eurprd04.prod.outlook.com>

Gentle ping...

> > From: Anson.Huang@nxp.com <Anson.Huang@nxp.com>
> > Sent: Thursday, July 18, 2019 9:32 AM
> >
> > Use the new helper devm_platform_ioremap_resource() which wraps the
> > platform_get_resource() and devm_ioremap_resource() together, to
> > simplify the code.
> >
> > Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> 
> Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
> 
> Regards
> Aisheng
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* Re: [PATCH 20/21] ASoC: sun4i-i2s: Add support for TDM slots
From: Sergey Suloev @ 2019-08-20  5:46 UTC (permalink / raw)
  To: Maxime Ripard, Chen-Yu Tsai, lgirdwood, broonie
  Cc: codekipper, alsa-devel, linux-kernel, linux-arm-kernel
In-Reply-To: <26392af30b3e7b31ee48d5b867d45be8675db046.1566242458.git-series.maxime.ripard@bootlin.com>

Hi, Maxime,

On 8/19/19 10:25 PM, Maxime Ripard wrote:
> From: Maxime Ripard <maxime.ripard@bootlin.com>
>
> The i2s controller supports TDM, for up to 8 slots. Let's support the TDM
> API.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> ---
>   sound/soc/sunxi/sun4i-i2s.c | 40 ++++++++++++++++++++++++++++++++------
>   1 file changed, 34 insertions(+), 6 deletions(-)
>
> diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
> index 0dac09814b65..4f76daeaaed7 100644
> --- a/sound/soc/sunxi/sun4i-i2s.c
> +++ b/sound/soc/sunxi/sun4i-i2s.c
> @@ -168,6 +168,8 @@ struct sun4i_i2s {
>   	struct reset_control *rst;
>   
>   	unsigned int	mclk_freq;
> +	unsigned int	slots;
> +	unsigned int	slot_width;
>   
>   	struct snd_dmaengine_dai_dma_data	capture_dma_data;
>   	struct snd_dmaengine_dai_dma_data	playback_dma_data;
> @@ -287,7 +289,7 @@ static bool sun4i_i2s_oversample_is_valid(unsigned int oversample)
>   
>   static int sun4i_i2s_set_clk_rate(struct snd_soc_dai *dai,
>   				  unsigned int rate,
> -				  unsigned int channels,
> +				  unsigned int slots,
>   				  unsigned int word_size)
>   {
>   	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
> @@ -335,7 +337,7 @@ static int sun4i_i2s_set_clk_rate(struct snd_soc_dai *dai,
>   
>   	bclk_parent_rate = i2s->variant->get_bclk_parent_rate(i2s);
>   	bclk_div = sun4i_i2s_get_bclk_div(i2s, bclk_parent_rate,
> -					  rate, channels, word_size);
> +					  rate, slots, word_size);
>   	if (bclk_div < 0) {
>   		dev_err(dai->dev, "Unsupported BCLK divider: %d\n", bclk_div);
>   		return -EINVAL;
> @@ -419,6 +421,10 @@ static int sun8i_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
>   				  const struct snd_pcm_hw_params *params)
>   {
>   	unsigned int channels = params_channels(params);
> +	unsigned int slots = channels;
> +
> +	if (i2s->slots)
> +		slots = i2s->slots;
>   
>   	/* Map the channels for playback and capture */
>   	regmap_write(i2s->regmap, SUN8I_I2S_TX_CHAN_MAP_REG, 0x76543210);
> @@ -428,7 +434,6 @@ static int sun8i_i2s_set_chan_cfg(const struct sun4i_i2s *i2s,
>   	regmap_update_bits(i2s->regmap, SUN8I_I2S_TX_CHAN_SEL_REG,
>   			   SUN4I_I2S_CHAN_SEL_MASK,
>   			   SUN4I_I2S_CHAN_SEL(channels));
> -
>   	regmap_update_bits(i2s->regmap, SUN8I_I2S_RX_CHAN_SEL_REG,
>   			   SUN4I_I2S_CHAN_SEL_MASK,
>   			   SUN4I_I2S_CHAN_SEL(channels));
> @@ -452,10 +457,18 @@ static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
>   			       struct snd_soc_dai *dai)
>   {
>   	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
> +	unsigned int word_size = params_width(params);
>   	unsigned int channels = params_channels(params);
> +	unsigned int slots = channels;
>   	int ret, sr, wss;
>   	u32 width;
>   
> +	if (i2s->slots)
> +		slots = i2s->slots;
> +
> +	if (i2s->slot_width)
> +		word_size = i2s->slot_width;
> +
>   	ret = i2s->variant->set_chan_cfg(i2s, params);
>   	if (ret < 0) {
>   		dev_err(dai->dev, "Invalid channel configuration\n");
> @@ -477,15 +490,14 @@ static int sun4i_i2s_hw_params(struct snd_pcm_substream *substream,
>   	if (sr < 0)
>   		return -EINVAL;
>   
> -	wss = i2s->variant->get_wss(i2s, params_width(params));
> +	wss = i2s->variant->get_wss(i2s, word_size);
>   	if (wss < 0)
>   		return -EINVAL;
>   
>   	regmap_field_write(i2s->field_fmt_wss, wss);
>   	regmap_field_write(i2s->field_fmt_sr, sr);
>   
> -	return sun4i_i2s_set_clk_rate(dai, params_rate(params),
> -				      channels, params_width(params));
> +	return sun4i_i2s_set_clk_rate(dai, params_rate(params), slots, word_size);
>   }
>   
>   static int sun4i_i2s_set_soc_fmt(const struct sun4i_i2s *i2s,
> @@ -785,10 +797,26 @@ static int sun4i_i2s_set_sysclk(struct snd_soc_dai *dai, int clk_id,
>   	return 0;
>   }
>   
> +static int sun4i_i2s_set_tdm_slot(struct snd_soc_dai *dai,
> +				  unsigned int tx_mask, unsigned int rx_mask,
> +				  int slots, int slot_width)
> +{
> +	struct sun4i_i2s *i2s = snd_soc_dai_get_drvdata(dai);
> +
> +	if (slots > 8)
> +		return -EINVAL;
> +
> +	i2s->slots = slots;
> +	i2s->slot_width = slot_width;
> +
> +	return 0;
> +}
> +
>   static const struct snd_soc_dai_ops sun4i_i2s_dai_ops = {
>   	.hw_params	= sun4i_i2s_hw_params,
>   	.set_fmt	= sun4i_i2s_set_fmt,
>   	.set_sysclk	= sun4i_i2s_set_sysclk,
> +	.set_tdm_slot	= sun4i_i2s_set_tdm_slot,
>   	.trigger	= sun4i_i2s_trigger,
>   };
>   


it seems like you forgot to implement sun4i_i2s_dai_ops.set_bclk_ratio 
because, as I far as I understand, it should alter tdm slots 
functionality indirectly.


Thank you,
SS



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* Re: Build regression in Linux 5.3-rc5 with CONFIG_XEN=y
From: Christoph Hellwig @ 2019-08-20  5:46 UTC (permalink / raw)
  To: Stefan Wahren
  Cc: Avaneesh Kumar Dwivedi, Bjorn Andersson, iommu, Ian Jackson,
	Stephen Boyd, Robin Murphy, Christoph Hellwig, linux-arm-kernel,
	Marek Szyprowski
In-Reply-To: <a69cce68-8c41-2030-b011-cdfacfeae421@gmx.net>

On Tue, Aug 20, 2019 at 07:43:52AM +0200, Stefan Wahren wrote:
> i applied this patch and it fixes the build issue i reported before. But
> this seems to reveal another build issue in drivers/firmware/qcom_scm.c:

Yes, I rean into this as well until I disabled the qcom platform.  But
this is in no way related to the swiotlb changes.

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* Re: [RFC 02/11] dt-bindings: power: amlogic, meson-gx-pwrc: Add SM1 bindings
From: Martin Blumenstingl @ 2019-08-20  5:45 UTC (permalink / raw)
  To: Kevin Hilman
  Cc: devicetree, Neil Armstrong, linux-kernel, linux-amlogic,
	linux-arm-kernel, jbrunet
In-Reply-To: <7h1rxgvgyj.fsf@baylibre.com>

Hi Kevin,

On Tue, Aug 20, 2019 at 2:06 AM Kevin Hilman <khilman@baylibre.com> wrote:
[...]
> >> +ao_sysctrl: sys-ctrl@0 {
> >> +       compatible = "amlogic,meson-gx-ao-sysctrl", "syscon", "simple-mfd";
> >> +       reg =  <0x0 0x0 0x0 0x100>;
> >> +
> >> +       pwrc: power-controller {
> >> +               compatible = "amlogic,meson-sm1-pwrc";
> >> +               #power-domain-cells = <1>;
> >> +               amlogic,hhi-sysctrl = <&hhi>;
> >> +       };
> >> +};
> >
> > I'm not sure that we want to mix HHI and AO power domains in one driver again
>
> We're not mixing here. These are all EE domains.  They just have some
> control registers in the AO memory region.
looking at patch 04/11 I see what you mean
(I'm describing it in my own words to make sure I got it right)
we are controlling the EE power domains with this binding.
each power domain has 1 bit in the HHI registers and 2 more bits
("sleep" and "isolation") in the AO region

then it makes sense to describe this together

> > back in March I asked a few questions about modelling the power
> > domains and Kevin explained that we can implement them hierarchical:
> > [0]
> > unfortunately I didn't have the time to work on this - however, now
> > that we implement a new driver: should we follow this hierarchical
> > approach?
>
> The more I look at this, I don't think we have a commpelling need to
> model them hierarchically.  The main reason being is that of the 3
> top-level domains I listed[0], we can only managing the EE domains in the
> kernel.  It doesn't make sense to model/manage AO domains because, well,
> they are always-on (AO).  The CPU domains are managed my the PSCI
> firmware, and we don't/won't have any control over that.
agreed, this is the same for the 32-bit SoCs except that we manage the
CPU domains in arch/arm/mach-meson/platsmp.c instead of PSCI firmware
(no problem here, I'm just mentioning it to get a complete picture)

> For that reason, I think it makes the most sense to have a generic
> driver that handles all the EE domains.
>
> IMO, the SM1 driver that Neil wrote in patch 4 of this series is 80%
> there.  If we generalize that little more, it can be quite easily used
> for all the EE domains.
with your description above I agree.

for the 32-bit SoCs it would be beneficial if the register layout in
the bindings was swapped:
- have the power controller as child of HHI
- pass the AO syscon

my main points for this are:
- it seems that for some power domains there are no AO register bits,
for example the Ethernet Memory PD (GXBB datasheet [0] section 18.3 on
page 48 and Meson8b datasheet [1] section 5.4 on page 17)
- less confusion: if it's a power domain controller for the EE region
then it should be located there, even if it has additional bits
elsewhere
- (weakest argument though) on the 32-bit SoCs we currently don't have
a "big AO syscon" (and I don't see that we actually need it), but we
do have a "amlogic,meson8b-pmu", "syscon" binding which covers
AO_RTI_GEN_PWR_SLEEP0 (I should probably extend it so it covers
AO_RTI_GEN_PWR_ISO0 as well, that just extra 4 bytes)

What do you think?


Martin


[0] https://dn.odroid.com/S905/DataSheet/S905_Public_Datasheet_V1.1.4.pdf
[1] https://dn.odroid.com/S805/Datasheet/S805_Datasheet%20V0.8%2020150126.pdf

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* Re: Build regression in Linux 5.3-rc5 with CONFIG_XEN=y
From: Stefan Wahren @ 2019-08-20  5:43 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Avaneesh Kumar Dwivedi, Bjorn Andersson, iommu, Ian Jackson,
	Stephen Boyd, Robin Murphy, linux-arm-kernel, Marek Szyprowski
In-Reply-To: <20190820012415.GA21178@lst.de>

Hi Christoph,

Am 20.08.19 um 03:24 schrieb Christoph Hellwig:
> Hi Stefan,
>
> please try the patch below.
>
> ---
> From e0570628d96faa50ebfc94ce8e545968336db225 Mon Sep 17 00:00:00 2001
> From: Christoph Hellwig <hch@lst.de>
> Date: Tue, 20 Aug 2019 10:08:38 +0900
> Subject: arm: select the dma-noncoherent symbols for all swiotlb builds
>
> We need to provide the arch hooks for non-coherent dma-direct
> and swiotlb for all swiotlb builds, not just when LPAS is enabled.
s/LPAS/LPAE/
> Without that the Xen build that selects SWIOTLB indirectly through
> SWIOTLB_XEN fails to build.
>
> Fixes: ad3c7b18c5b3 ("arm: use swiotlb for bounce buffering on LPAE configs")
> Reported-by: Stefan Wahren <wahrenst@gmx.net>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

i applied this patch and it fixes the build issue i reported before. But
this seems to reveal another build issue in drivers/firmware/qcom_scm.c:

drivers/firmware/qcom_scm.c: In function ‘qcom_scm_assign_mem’:
drivers/firmware/qcom_scm.c:460:47: error: passing argument 3 of
‘dma_alloc_coherent’ from incompatible pointer type
[-Werror=incompatible-pointer-types]
  ptr = dma_alloc_coherent(__scm->dev, ptr_sz, &ptr_phys, GFP_KERNEL);
                                               ^
In file included from drivers/firmware/qcom_scm.c:12:0:
./include/linux/dma-mapping.h:636:21: note: expected ‘dma_addr_t * {aka
long long unsigned int *}’ but argument is of type ‘phys_addr_t * {aka
unsigned int *}’
 static inline void *dma_alloc_coherent(struct device *dev, size_t size,
                     ^~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
scripts/Makefile.build:280: die Regel für Ziel
„drivers/firmware/qcom_scm.o“ scheiterte

Luckily there is already a patch to fix this in linux-next:

firmware: qcom_scm: Use proper types for dma mappings

It seems that it misses the fixes tag.

Regards
Stefan


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* Re: [PATCH v4] kasan: add memory corruption identification for software tag-based mode
From: Walter Wu @ 2019-08-20  5:37 UTC (permalink / raw)
  To: Andrey Ryabinin
  Cc: wsd_upstream, Vasily Gorbik, Arnd Bergmann, linux-mm,
	Andrey Konovalov, linux-kernel, kasan-dev, Martin Schwidefsky,
	Miles Chen, Alexander Potapenko, linux-arm-kernel,
	Matthias Brugger, linux-mediatek, Andrew Morton, Thomas Gleixner,
	Dmitry Vyukov
In-Reply-To: <20190806054340.16305-1-walter-zh.wu@mediatek.com>

On Tue, 2019-08-06 at 13:43 +0800, Walter Wu wrote:
> This patch adds memory corruption identification at bug report for
> software tag-based mode, the report show whether it is "use-after-free"
> or "out-of-bound" error instead of "invalid-access" error. This will make
> it easier for programmers to see the memory corruption problem.
> 
> We extend the slab to store five old free pointer tag and free backtrace,
> we can check if the tagged address is in the slab record and make a
> good guess if the object is more like "use-after-free" or "out-of-bound".
> therefore every slab memory corruption can be identified whether it's
> "use-after-free" or "out-of-bound".
> 
> ====== Changes
> Change since v1:
> - add feature option CONFIG_KASAN_SW_TAGS_IDENTIFY.
> - change QUARANTINE_FRACTION to reduce quarantine size.
> - change the qlist order in order to find the newest object in quarantine
> - reduce the number of calling kmalloc() from 2 to 1 time.
> - remove global variable to use argument to pass it.
> - correct the amount of qobject cache->size into the byes of qlist_head.
> - only use kasan_cache_shrink() to shink memory.
> 
> Change since v2:
> - remove the shinking memory function kasan_cache_shrink()
> - modify the description of the CONFIG_KASAN_SW_TAGS_IDENTIFY
> - optimize the quarantine_find_object() and qobject_free()
> - fix the duplicating function name 3 times in the header.
> - modify the function name set_track() to kasan_set_track()
> 
> Change since v3:
> - change tag-based quarantine to extend slab to identify memory corruption

Hi,Andrey,

Would you review the patch,please?
This patch is to pre-allocate slub record(tag and free backtrace) during
create slub object. When kernel has memory corruption, it will print
correct corruption type and free backtrace.

Thanks.

Walter


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* [nomadik:mtdparts 7/8] ERROR: "mtd_partition_split" [drivers/mtd/mtd.ko] undefined!
From: kbuild test robot @ 2019-08-20  4:06 UTC (permalink / raw)
  To: Linus Walleij; +Cc: kbuild-all, linux-arm-kernel

[-- Attachment #1: Type: text/plain, Size: 1010 bytes --]

tree:   https://kernel.googlesource.com/pub/scm/linux/kernel/git/linusw/linux-nomadik.git mtdparts
head:   05bbf79a61abe11ace5bdf9f21f7992ea117e475
commit: d35718b24f7d3239e97746c8f99ac1ef7da3a6ac [7/8] mtd: partions: Implement partition splitting
config: m68k-allmodconfig (attached as .config)
compiler: m68k-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git checkout d35718b24f7d3239e97746c8f99ac1ef7da3a6ac
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=m68k 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> ERROR: "mtd_partition_split" [drivers/mtd/mtd.ko] undefined!

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 50909 bytes --]

[-- Attachment #3: Type: text/plain, Size: 176 bytes --]

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^ permalink raw reply

* [PATCH v2 3/3] arm64: implement KPROBES_ON_FTRACE
From: Jisheng Zhang @ 2019-08-20  3:54 UTC (permalink / raw)
  To: Catalin Marinas, Jonathan Corbet, Will Deacon, Thomas Gleixner,
	Ingo Molnar, Borislav Petkov, H. Peter Anvin, x86@kernel.org,
	Naveen N. Rao, Anil S Keshavamurthy, David S. Miller,
	Masami Hiramatsu
  Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org
In-Reply-To: <20190820113928.1971900c@xhacker.debian>

KPROBES_ON_FTRACE avoids much of the overhead with regular kprobes as it
eliminates the need for a trap, as well as the need to emulate or
single-step instructions.

This patch implements KPROBES_ON_FTRACE for arm64.

Tested on berlin arm64 platform.

~ # mount -t debugfs debugfs /sys/kernel/debug/
~ # cd /sys/kernel/debug/
/sys/kernel/debug # echo 'p _do_fork' > tracing/kprobe_events

before the patch:

/sys/kernel/debug # cat kprobes/list
ffffff801009fe28  k  _do_fork+0x0    [DISABLED]

after the patch:

/sys/kernel/debug # cat kprobes/list
ffffff801009ff54  k  _do_fork+0x4    [DISABLED][FTRACE]

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
---
 .../debug/kprobes-on-ftrace/arch-support.txt  |  2 +-
 arch/arm64/Kconfig                            |  1 +
 arch/arm64/kernel/probes/Makefile             |  1 +
 arch/arm64/kernel/probes/ftrace.c             | 60 +++++++++++++++++++
 4 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm64/kernel/probes/ftrace.c

diff --git a/Documentation/features/debug/kprobes-on-ftrace/arch-support.txt b/Documentation/features/debug/kprobes-on-ftrace/arch-support.txt
index 68f266944d5f..e8358a38981c 100644
--- a/Documentation/features/debug/kprobes-on-ftrace/arch-support.txt
+++ b/Documentation/features/debug/kprobes-on-ftrace/arch-support.txt
@@ -9,7 +9,7 @@
     |       alpha: | TODO |
     |         arc: | TODO |
     |         arm: | TODO |
-    |       arm64: | TODO |
+    |       arm64: |  ok  |
     |         c6x: | TODO |
     |        csky: | TODO |
     |       h8300: | TODO |
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 663392d1eae2..928700f15e23 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -167,6 +167,7 @@ config ARM64
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_KPROBES
+	select HAVE_KPROBES_ON_FTRACE
 	select HAVE_KRETPROBES
 	select HAVE_GENERIC_VDSO
 	select IOMMU_DMA if IOMMU_SUPPORT
diff --git a/arch/arm64/kernel/probes/Makefile b/arch/arm64/kernel/probes/Makefile
index 8e4be92e25b1..4020cfc66564 100644
--- a/arch/arm64/kernel/probes/Makefile
+++ b/arch/arm64/kernel/probes/Makefile
@@ -4,3 +4,4 @@ obj-$(CONFIG_KPROBES)		+= kprobes.o decode-insn.o	\
 				   simulate-insn.o
 obj-$(CONFIG_UPROBES)		+= uprobes.o decode-insn.o	\
 				   simulate-insn.o
+obj-$(CONFIG_KPROBES_ON_FTRACE)	+= ftrace.o
diff --git a/arch/arm64/kernel/probes/ftrace.c b/arch/arm64/kernel/probes/ftrace.c
new file mode 100644
index 000000000000..52901ffff570
--- /dev/null
+++ b/arch/arm64/kernel/probes/ftrace.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Dynamic Ftrace based Kprobes Optimization
+ *
+ * Copyright (C) Hitachi Ltd., 2012
+ * Copyright (C) 2019 Jisheng Zhang <jszhang@kernel.org>
+ *		      Synaptics Incorporated
+ */
+
+#include <linux/kprobes.h>
+
+/* Ftrace callback handler for kprobes -- called under preepmt disabed */
+void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
+			   struct ftrace_ops *ops, struct pt_regs *regs)
+{
+	struct kprobe *p;
+	struct kprobe_ctlblk *kcb;
+
+	/* Preempt is disabled by ftrace */
+	p = get_kprobe((kprobe_opcode_t *)ip);
+	if (unlikely(!p) || kprobe_disabled(p))
+		return;
+
+	kcb = get_kprobe_ctlblk();
+	if (kprobe_running()) {
+		kprobes_inc_nmissed_count(p);
+	} else {
+		unsigned long orig_ip = instruction_pointer(regs);
+		/* Kprobe handler expects regs->pc = pc + 1 as breakpoint hit */
+		instruction_pointer_set(regs, ip + sizeof(kprobe_opcode_t));
+
+		__this_cpu_write(current_kprobe, p);
+		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
+		if (!p->pre_handler || !p->pre_handler(p, regs)) {
+			/*
+			 * Emulate singlestep (and also recover regs->pc)
+			 * as if there is a nop
+			 */
+			instruction_pointer_set(regs,
+				(unsigned long)p->addr + MCOUNT_INSN_SIZE);
+			if (unlikely(p->post_handler)) {
+				kcb->kprobe_status = KPROBE_HIT_SSDONE;
+				p->post_handler(p, regs, 0);
+			}
+			instruction_pointer_set(regs, orig_ip);
+		}
+		/*
+		 * If pre_handler returns !0, it changes regs->pc. We have to
+		 * skip emulating post_handler.
+		 */
+		__this_cpu_write(current_kprobe, NULL);
+	}
+}
+NOKPROBE_SYMBOL(kprobe_ftrace_handler);
+
+int arch_prepare_kprobe_ftrace(struct kprobe *p)
+{
+	p->ainsn.api.insn = NULL;
+	return 0;
+}
-- 
2.23.0.rc1


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^ permalink raw reply related

* [PATCH v2 2/3] kprobes: adjust kprobe addr for KPROBES_ON_FTRACE
From: Jisheng Zhang @ 2019-08-20  3:53 UTC (permalink / raw)
  To: Catalin Marinas, Jonathan Corbet, Will Deacon, Thomas Gleixner,
	Ingo Molnar, Borislav Petkov, H. Peter Anvin, x86@kernel.org,
	Naveen N. Rao, Anil S Keshavamurthy, David S. Miller,
	Masami Hiramatsu
  Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org
In-Reply-To: <20190820113928.1971900c@xhacker.debian>

For KPROBES_ON_FTRACE case, we need to adjust the kprobe's addr
correspondingly.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
---
 kernel/kprobes.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 9873fc627d61..3fd2f68644da 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1484,15 +1484,19 @@ static inline int check_kprobe_rereg(struct kprobe *p)
 
 int __weak arch_check_ftrace_location(struct kprobe *p)
 {
-	unsigned long ftrace_addr;
+	unsigned long ftrace_addr, addr = (unsigned long)p->addr;
 
-	ftrace_addr = ftrace_location((unsigned long)p->addr);
+#ifdef CONFIG_KPROBES_ON_FTRACE
+	addr = ftrace_call_adjust(addr);
+#endif
+	ftrace_addr = ftrace_location(addr);
 	if (ftrace_addr) {
 #ifdef CONFIG_KPROBES_ON_FTRACE
 		/* Given address is not on the instruction boundary */
-		if ((unsigned long)p->addr != ftrace_addr)
+		if (addr != ftrace_addr)
 			return -EILSEQ;
 		p->flags |= KPROBE_FLAG_FTRACE;
+		p->addr = (kprobe_opcode_t *)addr;
 #else	/* !CONFIG_KPROBES_ON_FTRACE */
 		return -EINVAL;
 #endif
-- 
2.23.0.rc1


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^ permalink raw reply related

* [PATCH v2 1/3] kprobes/x86: use instruction_pointer and instruction_pointer_set
From: Jisheng Zhang @ 2019-08-20  3:52 UTC (permalink / raw)
  To: Catalin Marinas, Jonathan Corbet, Will Deacon, Thomas Gleixner,
	Ingo Molnar, Borislav Petkov, H. Peter Anvin, x86@kernel.org,
	Naveen N. Rao, Anil S Keshavamurthy, David S. Miller,
	Masami Hiramatsu
  Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org
In-Reply-To: <20190820113928.1971900c@xhacker.debian>

This is to make the x86 kprobe_ftrace_handler() more common so that
the code could be reused in future.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 arch/x86/kernel/kprobes/ftrace.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/kprobes/ftrace.c b/arch/x86/kernel/kprobes/ftrace.c
index 681a4b36e9bb..c2ad0b9259ca 100644
--- a/arch/x86/kernel/kprobes/ftrace.c
+++ b/arch/x86/kernel/kprobes/ftrace.c
@@ -28,9 +28,9 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 	if (kprobe_running()) {
 		kprobes_inc_nmissed_count(p);
 	} else {
-		unsigned long orig_ip = regs->ip;
+		unsigned long orig_ip = instruction_pointer(regs);
 		/* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */
-		regs->ip = ip + sizeof(kprobe_opcode_t);
+		instruction_pointer_set(regs, ip + sizeof(kprobe_opcode_t));
 
 		__this_cpu_write(current_kprobe, p);
 		kcb->kprobe_status = KPROBE_HIT_ACTIVE;
@@ -39,12 +39,13 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 			 * Emulate singlestep (and also recover regs->ip)
 			 * as if there is a 5byte nop
 			 */
-			regs->ip = (unsigned long)p->addr + MCOUNT_INSN_SIZE;
+			instruction_pointer_set(regs,
+				(unsigned long)p->addr + MCOUNT_INSN_SIZE);
 			if (unlikely(p->post_handler)) {
 				kcb->kprobe_status = KPROBE_HIT_SSDONE;
 				p->post_handler(p, regs, 0);
 			}
-			regs->ip = orig_ip;
+			instruction_pointer_set(regs, orig_ip);
 		}
 		/*
 		 * If pre_handler returns !0, it changes regs->ip. We have to
-- 
2.23.0.rc1


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^ permalink raw reply related

* [PATCH v2 0/3] arm64: KPROBES_ON_FTRACE
From: Jisheng Zhang @ 2019-08-20  3:50 UTC (permalink / raw)
  To: Catalin Marinas, Jonathan Corbet, Will Deacon, Thomas Gleixner,
	Ingo Molnar, Borislav Petkov, H. Peter Anvin, x86@kernel.org,
	Naveen N. Rao, Anil S Keshavamurthy, David S. Miller,
	Masami Hiramatsu
  Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org

KPROBES_ON_FTRACE avoids much of the overhead with regular kprobes as it
eliminates the need for a trap, as well as the need to emulate or
single-step instructions.

Applied after arm64 FTRACE_WITH_REGS:
http://lists.infradead.org/pipermail/linux-arm-kernel/2019-August/674404.html

Changes since v1:
  - make the kprobes/x86: use instruction_pointer and instruction_pointer_set
    as patch1
  - add Masami's ACK to patch1
  - add some description about KPROBES_ON_FTRACE and why we need it on
    arm64
  - correct the log before the patch
  - remove the consolidation patch, make it as TODO
  - only adjust kprobe's addr when KPROBE_FLAG_FTRACE is set
  - if KPROBES_ON_FTRACE, ftrace_call_adjust() the kprobe's addr before
    calling ftrace_location()
  - update the kprobes-on-ftrace/arch-support.txt in doc

Jisheng Zhang (3):
  kprobes/x86: use instruction_pointer and instruction_pointer_set
  kprobes: adjust kprobe addr for KPROBES_ON_FTRACE
  arm64: implement KPROBES_ON_FTRACE

 .../debug/kprobes-on-ftrace/arch-support.txt  |  2 +-
 arch/arm64/Kconfig                            |  1 +
 arch/arm64/kernel/probes/Makefile             |  1 +
 arch/arm64/kernel/probes/ftrace.c             | 60 +++++++++++++++++++
 arch/x86/kernel/kprobes/ftrace.c              |  9 +--
 kernel/kprobes.c                              | 10 +++-
 6 files changed, 75 insertions(+), 8 deletions(-)
 create mode 100644 arch/arm64/kernel/probes/ftrace.c

-- 
2.23.0.rc1


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^ permalink raw reply

* Re: [v4, 7/8] cpufreq: mediatek: add opp notification for SVS support
From: Viresh Kumar @ 2019-08-20  3:39 UTC (permalink / raw)
  To: Andrew-sh.Cheng
  Cc: Mark Rutland, Nishanth Menon, srv_heupstream, linux-pm,
	Stephen Boyd, Rafael J. Wysocki, linux-kernel, Rob Herring,
	Chanwoo Choi, Kyungmin Park, MyungJoo Ham, linux-mediatek,
	linux-arm-kernel, Matthias Brugger, fan.chen, devicetree
In-Reply-To: <1565703113-31479-8-git-send-email-andrew-sh.cheng@mediatek.com>

On 13-08-19, 21:31, Andrew-sh.Cheng wrote:
> From: "Andrew-sh.Cheng" <andrew-sh.cheng@mediatek.com>
> 
> cpufreq should listen opp notification and do proper actions
> when receiving disable and voltage adjustment events,
> which are triggered when SVS is enabled.
> 
> Signed-off-by: Andrew-sh.Cheng <andrew-sh.cheng@mediatek.com>
> ---
>  drivers/cpufreq/mediatek-cpufreq.c | 78 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 78 insertions(+)
> 
> diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
> index 4dce41b18369..9820c8003507 100644
> --- a/drivers/cpufreq/mediatek-cpufreq.c
> +++ b/drivers/cpufreq/mediatek-cpufreq.c
> @@ -42,6 +42,10 @@ struct mtk_cpu_dvfs_info {
>  	struct list_head list_head;
>  	int intermediate_voltage;
>  	bool need_voltage_tracking;
> +	struct mutex lock; /* avoid notify and policy race condition */
> +	struct notifier_block opp_nb;
> +	int opp_cpu;
> +	unsigned long opp_freq;
>  };
>  
>  static LIST_HEAD(dvfs_info_list);
> @@ -231,6 +235,7 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
>  	vproc = dev_pm_opp_get_voltage(opp);
>  	dev_pm_opp_put(opp);
>  
> +	mutex_lock(&info->lock);
>  	/*
>  	 * If the new voltage or the intermediate voltage is higher than the
>  	 * current voltage, scale up voltage first.
> @@ -242,6 +247,7 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
>  			pr_err("cpu%d: failed to scale up voltage!\n",
>  			       policy->cpu);
>  			mtk_cpufreq_set_voltage(info, old_vproc);
> +			mutex_unlock(&info->lock);
>  			return ret;
>  		}
>  	}
> @@ -253,6 +259,7 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
>  		       policy->cpu);
>  		mtk_cpufreq_set_voltage(info, old_vproc);
>  		WARN_ON(1);
> +		mutex_unlock(&info->lock);
>  		return ret;
>  	}
>  
> @@ -263,6 +270,7 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
>  		       policy->cpu);
>  		clk_set_parent(cpu_clk, armpll);
>  		mtk_cpufreq_set_voltage(info, old_vproc);
> +		mutex_unlock(&info->lock);
>  		return ret;
>  	}
>  
> @@ -273,6 +281,7 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
>  		       policy->cpu);
>  		mtk_cpufreq_set_voltage(info, inter_vproc);
>  		WARN_ON(1);
> +		mutex_unlock(&info->lock);
>  		return ret;
>  	}
>  
> @@ -288,15 +297,74 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
>  			clk_set_parent(cpu_clk, info->inter_clk);
>  			clk_set_rate(armpll, old_freq_hz);
>  			clk_set_parent(cpu_clk, armpll);
> +			mutex_unlock(&info->lock);
>  			return ret;
>  		}
>  	}
>  
> +	info->opp_freq = freq_hz;
> +	mutex_unlock(&info->lock);
> +
>  	return 0;
>  }
>  
>  #define DYNAMIC_POWER "dynamic-power-coefficient"
>  
> +static int mtk_cpufreq_opp_notifier(struct notifier_block *nb,
> +				    unsigned long event, void *data)
> +{
> +	struct dev_pm_opp *opp = data;
> +	struct dev_pm_opp *opp_item;
> +	struct mtk_cpu_dvfs_info *info =
> +		container_of(nb, struct mtk_cpu_dvfs_info, opp_nb);
> +	unsigned long freq, volt;
> +	struct cpufreq_policy *policy;
> +	int ret = 0;
> +
> +	if (event == OPP_EVENT_ADJUST_VOLTAGE) {
> +		freq = dev_pm_opp_get_freq(opp);
> +
> +		mutex_lock(&info->lock);
> +		if (info->opp_freq == freq) {
> +			volt = dev_pm_opp_get_voltage(opp);
> +			ret = mtk_cpufreq_set_voltage(info, volt);
> +			if (ret)
> +				dev_err(info->cpu_dev, "failed to scale voltage: %d\n",
> +					ret);
> +		}
> +		mutex_unlock(&info->lock);
> +	} else if (event == OPP_EVENT_DISABLE) {

Does this ever get called for your platform ? Why are you using opp disable ?
Maybe we can avoid it completely.

> +		freq = info->opp_freq;
> +		opp_item = dev_pm_opp_find_freq_ceil(info->cpu_dev, &freq);
> +		if (!IS_ERR(opp_item))
> +			dev_pm_opp_put(opp_item);
> +		else
> +			freq = 0;
> +
> +		/* case of current opp is disabled */
> +		if (freq == 0 || freq != info->opp_freq) {
> +			// find an enable opp item
> +			freq = 1;
> +			opp_item = dev_pm_opp_find_freq_ceil(info->cpu_dev,
> +							     &freq);
> +			if (!IS_ERR(opp_item)) {
> +				dev_pm_opp_put(opp_item);
> +				policy = cpufreq_cpu_get(info->opp_cpu);
> +				if (policy) {
> +					cpufreq_driver_target(policy,
> +						freq / 1000,
> +						CPUFREQ_RELATION_L);
> +					cpufreq_cpu_put(policy);
> +				}
> +			} else
> +				pr_err("%s: all opp items are disabled\n",
> +				       __func__);
> +		}
> +	}
> +
> +	return notifier_from_errno(ret);
> +}
> +
>  static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
>  {
>  	struct device *cpu_dev;
> @@ -383,11 +451,21 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
>  	info->intermediate_voltage = dev_pm_opp_get_voltage(opp);
>  	dev_pm_opp_put(opp);
>  
> +	info->opp_cpu = cpu;
> +	info->opp_nb.notifier_call = mtk_cpufreq_opp_notifier;
> +	ret = dev_pm_opp_register_notifier(cpu_dev, &info->opp_nb);
> +	if (ret) {
> +		pr_warn("cannot register opp notification\n");
> +		goto out_free_opp_table;
> +	}
> +
> +	mutex_init(&info->lock);
>  	info->cpu_dev = cpu_dev;
>  	info->proc_reg = proc_reg;
>  	info->sram_reg = IS_ERR(sram_reg) ? NULL : sram_reg;
>  	info->cpu_clk = cpu_clk;
>  	info->inter_clk = inter_clk;
> +	info->opp_freq = clk_get_rate(cpu_clk);
>  
>  	/*
>  	 * If SRAM regulator is present, software "voltage tracking" is needed
> -- 
> 2.12.5

-- 
viresh

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* [PATCH RESEND v11 8/8] selftests: add openat2(2) selftests
From: Aleksa Sarai @ 2019-08-20  3:34 UTC (permalink / raw)
  To: Al Viro, Jeff Layton, J. Bruce Fields, Arnd Bergmann,
	David Howells, Shuah Khan, Shuah Khan
  Cc: linux-ia64, linux-sh, Alexei Starovoitov, Oleg Nesterov,
	linux-kselftest, sparclinux, linux-arch, linux-s390,
	Tycho Andersen, Aleksa Sarai, linux-arm-kernel, linux-mips,
	linux-xtensa, Kees Cook, Jann Horn, linuxppc-dev, Aleksa Sarai,
	Andy Lutomirski, David Drysdale, Christian Brauner, linux-parisc,
	linux-m68k, linux-api, Chanho Min, linux-kernel, Eric Biederman,
	linux-alpha, linux-fsdevel, Andrew Morton, Linus Torvalds,
	containers
In-Reply-To: <20190820033406.29796-1-cyphar@cyphar.com>

Test all of the various openat2(2) flags, as well as how file
descriptor re-opening works. A small stress-test of a symlink-rename
attack is included to show that the protections against ".."-based
attacks are sufficient.

In addition, the memfd selftest is fixed to no longer depend on the
now-disallowed functionality of upgrading an O_RDONLY descriptor to
O_RDWR.

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
 tools/testing/selftests/Makefile              |   1 +
 tools/testing/selftests/memfd/memfd_test.c    |   7 +-
 tools/testing/selftests/openat2/.gitignore    |   1 +
 tools/testing/selftests/openat2/Makefile      |   8 +
 tools/testing/selftests/openat2/helpers.c     | 162 +++++++
 tools/testing/selftests/openat2/helpers.h     | 116 +++++
 .../testing/selftests/openat2/linkmode_test.c | 333 +++++++++++++++
 .../selftests/openat2/rename_attack_test.c    | 127 ++++++
 .../testing/selftests/openat2/resolve_test.c  | 402 ++++++++++++++++++
 9 files changed, 1155 insertions(+), 2 deletions(-)
 create mode 100644 tools/testing/selftests/openat2/.gitignore
 create mode 100644 tools/testing/selftests/openat2/Makefile
 create mode 100644 tools/testing/selftests/openat2/helpers.c
 create mode 100644 tools/testing/selftests/openat2/helpers.h
 create mode 100644 tools/testing/selftests/openat2/linkmode_test.c
 create mode 100644 tools/testing/selftests/openat2/rename_attack_test.c
 create mode 100644 tools/testing/selftests/openat2/resolve_test.c

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 25b43a8c2b15..13c02e0d0efc 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -37,6 +37,7 @@ TARGETS += powerpc
 TARGETS += proc
 TARGETS += pstore
 TARGETS += ptrace
+TARGETS += openat2
 TARGETS += rseq
 TARGETS += rtc
 TARGETS += seccomp
diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
index c67d32eeb668..e71df3d3e55d 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -925,7 +925,7 @@ static void test_share_mmap(char *banner, char *b_suffix)
  */
 static void test_share_open(char *banner, char *b_suffix)
 {
-	int fd, fd2;
+	int procfd, fd, fd2;
 
 	printf("%s %s %s\n", memfd_str, banner, b_suffix);
 
@@ -950,13 +950,16 @@ static void test_share_open(char *banner, char *b_suffix)
 	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK);
 	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK);
 
+	/* We cannot do a MAY_WRITE re-open of an O_RDONLY fd. */
+	procfd = mfd_assert_open(fd2, O_PATH, 0);
 	close(fd2);
-	fd2 = mfd_assert_open(fd, O_RDWR, 0);
+	fd2 = mfd_assert_open(procfd, O_WRONLY, 0);
 
 	mfd_assert_add_seals(fd2, F_SEAL_SEAL);
 	mfd_assert_has_seals(fd, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
 	mfd_assert_has_seals(fd2, F_SEAL_WRITE | F_SEAL_SHRINK | F_SEAL_SEAL);
 
+	close(procfd);
 	close(fd2);
 	close(fd);
 }
diff --git a/tools/testing/selftests/openat2/.gitignore b/tools/testing/selftests/openat2/.gitignore
new file mode 100644
index 000000000000..bd68f6c3fd07
--- /dev/null
+++ b/tools/testing/selftests/openat2/.gitignore
@@ -0,0 +1 @@
+/*_test
diff --git a/tools/testing/selftests/openat2/Makefile b/tools/testing/selftests/openat2/Makefile
new file mode 100644
index 000000000000..a0c1b53fd268
--- /dev/null
+++ b/tools/testing/selftests/openat2/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0
+
+CFLAGS += -Wall -O2 -g
+TEST_GEN_PROGS := linkmode_test resolve_test rename_attack_test
+
+include ../lib.mk
+
+$(TEST_GEN_PROGS): helpers.c
diff --git a/tools/testing/selftests/openat2/helpers.c b/tools/testing/selftests/openat2/helpers.c
new file mode 100644
index 000000000000..b9b7c7fc7a99
--- /dev/null
+++ b/tools/testing/selftests/openat2/helpers.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Author: Aleksa Sarai <cyphar@cyphar.com>
+ * Copyright (C) 2018-2019 SUSE LLC.
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <string.h>
+#include <syscall.h>
+#include <limits.h>
+
+#include "helpers.h"
+
+int sys_openat2(int dfd, const char *path, const struct open_how *how)
+{
+	int ret = syscall(__NR_openat2, dfd, path, how);
+	return ret >= 0 ? ret : -errno;
+}
+
+int sys_openat(int dfd, const char *path, const struct open_how *how)
+{
+	int ret = openat(dfd, path, how->flags, how->mode);
+	return ret >= 0 ? ret : -errno;
+}
+
+int sys_renameat2(int olddirfd, const char *oldpath,
+		  int newdirfd, const char *newpath, unsigned int flags)
+{
+	int ret = syscall(__NR_renameat2, olddirfd, oldpath,
+					  newdirfd, newpath, flags);
+	return ret >= 0 ? ret : -errno;
+}
+
+char *openat_flags(unsigned int flags)
+{
+	char *flagset, *accmode = "(none)";
+
+	switch (flags & 0x03) {
+	case O_RDWR:
+		accmode = "O_RDWR";
+		break;
+	case O_RDONLY:
+		accmode = "O_RDONLY";
+		break;
+	case O_WRONLY:
+		accmode = "O_WRONLY";
+		break;
+	}
+
+	E_asprintf(&flagset, "%s%s%s",
+		   (flags & O_PATH) ? "O_PATH|" : "",
+		   (flags & O_CREAT) ? "O_CREAT|" : "",
+		   accmode);
+
+	return flagset;
+}
+
+char *openat2_flags(const struct open_how *how)
+{
+	char *p;
+	char *flags_set, *resolve_set, *acc_set, *set;
+
+	flags_set = openat_flags(how->flags);
+
+	E_asprintf(&resolve_set, "%s%s%s%s%s0",
+		   (how->resolve & RESOLVE_NO_XDEV) ? "RESOLVE_NO_XDEV|" : "",
+		   (how->resolve & RESOLVE_NO_MAGICLINKS) ? "RESOLVE_NO_MAGICLINKS|" : "",
+		   (how->resolve & RESOLVE_NO_SYMLINKS) ? "RESOLVE_NO_SYMLINKS|" : "",
+		   (how->resolve & RESOLVE_BENEATH) ? "RESOLVE_BENEATH|" : "",
+		   (how->resolve & RESOLVE_IN_ROOT) ? "RESOLVE_IN_ROOT|" : "");
+
+	/* Remove trailing "|0". */
+	p = strstr(resolve_set, "|0");
+	if (p)
+		*p = '\0';
+
+	if (how->flags & O_PATH)
+		E_asprintf(&acc_set, ", upgrade_mask=%s%s0",
+			   (how->upgrade_mask & UPGRADE_NOREAD) ? "UPGRADE_NOREAD|" : "",
+			   (how->upgrade_mask & UPGRADE_NOWRITE) ? "UPGRADE_NOWRITE|" : "");
+	else if (how->flags & O_CREAT)
+		E_asprintf(&acc_set, ", mode=0%o", how->mode);
+	else
+		acc_set = strdup("");
+
+	/* Remove trailing "|0". */
+	p = strstr(acc_set, "|0");
+	if (p)
+		*p = '\0';
+
+	/* And now generate our flagset. */
+	E_asprintf(&set, "[flags=%s, resolve=%s%s]",
+		   flags_set, resolve_set, acc_set);
+
+	free(flags_set);
+	free(resolve_set);
+	free(acc_set);
+	return set;
+}
+
+int touchat(int dfd, const char *path)
+{
+	int fd = openat(dfd, path, O_CREAT);
+	if (fd >= 0)
+		close(fd);
+	return fd;
+}
+
+char *fdreadlink(int fd)
+{
+	char *target, *tmp;
+
+	E_asprintf(&tmp, "/proc/self/fd/%d", fd);
+
+	target = malloc(PATH_MAX);
+	if (!target)
+		ksft_exit_fail_msg("fdreadlink: malloc failed\n");
+	memset(target, 0, PATH_MAX);
+
+	E_readlink(tmp, target, PATH_MAX);
+	free(tmp);
+	return target;
+}
+
+bool fdequal(int fd, int dfd, const char *path)
+{
+	char *fdpath, *dfdpath, *other;
+	bool cmp;
+
+	fdpath = fdreadlink(fd);
+	dfdpath = fdreadlink(dfd);
+
+	if (!path)
+		E_asprintf(&other, "%s", dfdpath);
+	else if (*path == '/')
+		E_asprintf(&other, "%s", path);
+	else
+		E_asprintf(&other, "%s/%s", dfdpath, path);
+
+	cmp = !strcmp(fdpath, other);
+	if (!cmp)
+		ksft_print_msg("fdequal: expected '%s' but got '%s'\n", other, fdpath);
+
+	free(fdpath);
+	free(dfdpath);
+	free(other);
+	return cmp;
+}
+
+void test_openat2_supported(void)
+{
+	struct open_how how = {};
+	int fd = sys_openat2(AT_FDCWD, ".", &how);
+	if (fd == -ENOSYS)
+		ksft_exit_skip("openat2(2) unsupported on this kernel\n");
+	if (fd < 0)
+		ksft_exit_fail_msg("openat2(2) supported check failed: %s\n", strerror(-fd));
+	close(fd);
+}
diff --git a/tools/testing/selftests/openat2/helpers.h b/tools/testing/selftests/openat2/helpers.h
new file mode 100644
index 000000000000..43fa7835950f
--- /dev/null
+++ b/tools/testing/selftests/openat2/helpers.h
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Author: Aleksa Sarai <cyphar@cyphar.com>
+ * Copyright (C) 2018-2019 SUSE LLC.
+ */
+
+#ifndef __RESOLVEAT_H__
+#define __RESOLVEAT_H__
+
+#define _GNU_SOURCE
+#include <stdint.h>
+#include <errno.h>
+#include "../kselftest.h"
+
+#define ARRAY_LEN(X) (sizeof (X) / sizeof (*(X)))
+#define BUILD_BUG_ON(e) ((void)(sizeof(struct { int:(-!!(e)); })))
+
+#ifndef SYS_openat2
+#ifndef __NR_openat2
+#define __NR_openat2 437
+#endif /* __NR_openat2 */
+#define SYS_openat2 __NR_openat2
+#endif /* SYS_openat2 */
+
+/**
+ * Arguments for how openat2(2) should open the target path. If @extra is zero,
+ * then openat2 is identical to openat(2). Only one of @mode or @upgrade_mask
+ * may be set at any given time.
+ *
+ * @flags: O_* flags (unknown flags ignored).
+ * @mode: O_CREAT file mode (ignored otherwise).
+ * @upgrade_mask: restrict how the O_PATH may be re-opened (ignored otherwise).
+ * @resolve: RESOLVE_* flags (-EINVAL on unknown flags).
+ * @reserved: reserved for future extensions, must be zeroed.
+ */
+struct open_how {
+	uint32_t flags;
+	union {
+		uint16_t mode;
+		uint16_t upgrade_mask;
+	};
+	uint16_t resolve;
+	uint64_t reserved[7]; /* must be zeroed */
+};
+
+#ifndef RESOLVE_INROOT
+/* how->resolve flags for openat2(2). */
+#define RESOLVE_NO_XDEV		0x01 /* Block mount-point crossings
+					(includes bind-mounts). */
+#define RESOLVE_NO_MAGICLINKS	0x02 /* Block traversal through procfs-style
+					"magic-links". */
+#define RESOLVE_NO_SYMLINKS	0x04 /* Block traversal through all symlinks
+					(implies OEXT_NO_MAGICLINKS) */
+#define RESOLVE_BENEATH		0x08 /* Block "lexical" trickery like
+					"..", symlinks, and absolute
+					paths which escape the dirfd. */
+#define RESOLVE_IN_ROOT		0x10 /* Make all jumps to "/" and ".."
+					be scoped inside the dirfd
+					(similar to chroot(2)). */
+#endif /* RESOLVE_IN_ROOT */
+
+#ifndef UPGRADE_NOREAD
+/* how->upgrade flags for openat2(2). */
+/* First bit is reserved for a future UPGRADE_NOEXEC flag. */
+#define UPGRADE_NOREAD		0x02 /* Block re-opening with MAY_READ. */
+#define UPGRADE_NOWRITE		0x04 /* Block re-opening with MAY_WRITE. */
+#endif /* UPGRADE_NOREAD */
+
+#ifndef O_EMPTYPATH
+#define	O_EMPTYPATH 040000000
+#endif /* O_EMPTYPATH */
+
+#define E_func(func, ...)						\
+	do {								\
+		if (func(__VA_ARGS__) < 0)				\
+			ksft_exit_fail_msg("%s:%d %s failed\n", \
+					   __FILE__, __LINE__, #func);\
+	} while (0)
+
+#define E_mkdirat(...)   E_func(mkdirat,   __VA_ARGS__)
+#define E_symlinkat(...) E_func(symlinkat, __VA_ARGS__)
+#define E_touchat(...)   E_func(touchat,   __VA_ARGS__)
+#define E_readlink(...)  E_func(readlink,  __VA_ARGS__)
+#define E_fstatat(...)   E_func(fstatat,   __VA_ARGS__)
+#define E_asprintf(...)  E_func(asprintf,  __VA_ARGS__)
+#define E_fchdir(...)    E_func(fchdir,    __VA_ARGS__)
+#define E_mount(...)     E_func(mount,     __VA_ARGS__)
+#define E_unshare(...)   E_func(unshare,   __VA_ARGS__)
+#define E_setresuid(...) E_func(setresuid, __VA_ARGS__)
+#define E_chmod(...)     E_func(chmod,     __VA_ARGS__)
+
+#define E_assert(expr, msg, ...)					\
+	do {								\
+		if (!(expr))						\
+			ksft_exit_fail_msg("ASSERT(%s:%d) failed (%s): " msg "\n", \
+					   __FILE__, __LINE__, #expr, ##__VA_ARGS__); \
+	} while (0)
+
+typedef int (*openfunc_t)(int dfd, const char *path, const struct open_how *how);
+
+int sys_openat2(int dfd, const char *path, const struct open_how *how);
+char *openat2_flags(const struct open_how *how);
+
+int sys_openat(int dfd, const char *path, const struct open_how *how);
+char *openat_flags(unsigned int flags);
+
+int sys_renameat2(int olddirfd, const char *oldpath,
+		  int newdirfd, const char *newpath, unsigned int flags);
+
+int touchat(int dfd, const char *path);
+char *fdreadlink(int fd);
+bool fdequal(int fd, int dfd, const char *path);
+
+void test_openat2_supported(void);
+
+#endif /* __RESOLVEAT_H__ */
diff --git a/tools/testing/selftests/openat2/linkmode_test.c b/tools/testing/selftests/openat2/linkmode_test.c
new file mode 100644
index 000000000000..44fcba738686
--- /dev/null
+++ b/tools/testing/selftests/openat2/linkmode_test.c
@@ -0,0 +1,333 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Author: Aleksa Sarai <cyphar@cyphar.com>
+ * Copyright (C) 2018-2019 SUSE LLC.
+ */
+
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include "../kselftest.h"
+#include "helpers.h"
+
+static mode_t fdmode(int fd)
+{
+	char *fdpath;
+	struct stat statbuf;
+	mode_t mode;
+
+	E_asprintf(&fdpath, "/proc/self/fd/%d", fd);
+	E_fstatat(AT_FDCWD, fdpath, &statbuf, AT_SYMLINK_NOFOLLOW);
+	mode = (statbuf.st_mode & ~S_IFMT);
+	free(fdpath);
+
+	return mode;
+}
+
+static int reopen_proc(int fd, unsigned int flags)
+{
+	int ret, saved_errno;
+	char *fdpath;
+
+	E_asprintf(&fdpath, "/proc/self/fd/%d", fd);
+	ret = open(fdpath, flags);
+	saved_errno = errno;
+	free(fdpath);
+
+	return ret >= 0 ? ret : -saved_errno;
+}
+
+static int reopen_oemptypath(int fd, unsigned int flags)
+{
+	int ret = openat(fd, "", O_EMPTYPATH | flags);
+	return ret >= 0 ? ret : -errno;
+}
+
+struct reopen_test {
+	openfunc_t open;
+	mode_t chmod_mode;
+	struct {
+		struct open_how how;
+		mode_t mode;
+		int err;
+	} orig, new;
+};
+
+static bool reopen(int fd, struct reopen_test *test)
+{
+	int newfd;
+	mode_t proc_mode;
+	bool failed = false;
+
+	/* Check that the proc mode is correct. */
+	proc_mode = fdmode(fd);
+	if (proc_mode != test->orig.mode) {
+		ksft_print_msg("incorrect fdmode (got[%o] != want[%o])\n",
+			       proc_mode, test->orig.mode);
+		failed = true;
+	}
+
+	/* Re-open through /proc. */
+	newfd = reopen_proc(fd, test->new.how.flags);
+	if (newfd != test->new.err && (newfd < 0 || test->new.err < 0)) {
+		ksft_print_msg("/proc failure (%d != %d [%s])\n",
+			       newfd, test->new.err, strerror(-test->new.err));
+		failed = true;
+	}
+	if (newfd >= 0) {
+		proc_mode = fdmode(newfd);
+		if (proc_mode != test->new.mode) {
+			ksft_print_msg("/proc wrong fdmode (got[%o] != want[%o])\n",
+				       proc_mode, test->new.mode);
+			failed = true;
+		}
+		close(newfd);
+	}
+
+	/* Re-open with O_EMPTYPATH. */
+	newfd = reopen_oemptypath(fd, test->new.how.flags);
+	if (newfd != test->new.err && (newfd < 0 || test->new.err < 0)) {
+		ksft_print_msg("O_EMPTYPATH failure (%d != %d [%s])\n",
+			       newfd, test->new.err, strerror(-test->new.err));
+		failed = true;
+	}
+	if (newfd >= 0) {
+		proc_mode = fdmode(newfd);
+		if (proc_mode != test->new.mode) {
+			ksft_print_msg("O_EMPTYPATH wrong fdmode (got[%o] != want[%o])\n",
+				       proc_mode, test->new.mode);
+			failed = true;
+		}
+		close(newfd);
+	}
+
+	return failed;
+}
+
+#define NUM_REOPEN_TESTS 28
+
+void test_reopen_ordinary(bool privileged)
+{
+	int fd;
+	int err_access = privileged ? 0 : -EACCES;
+	char tmpfile[] = "/tmp/ksft-openat2-reopen-testfile.XXXXXX";
+
+	fd = mkstemp(tmpfile);
+	E_assert(fd >= 0, "mkstemp failed: %m\n");
+	close(fd);
+
+	struct reopen_test tests[] = {
+		/* Re-opening with the same mode should succeed. */
+		{ .open = sys_openat,	  .chmod_mode = 0400,
+		  .orig.how.flags = O_RDONLY, .orig.mode  = 0500,
+		  .new.how.flags  = O_RDONLY, .new.mode   = 0500 },
+		{ .open = sys_openat,	  .chmod_mode = 0200,
+		  .orig.how.flags = O_WRONLY, .orig.mode  = 0300,
+		  .new.how.flags  = O_WRONLY, .new.mode   = 0300 },
+		{ .open = sys_openat,	  .chmod_mode = 0600,
+		  .orig.how.flags =   O_RDWR, .orig.mode  = 0700,
+		  .new.how.flags  =   O_RDWR, .new.mode   = 0700 },
+		{ .open = sys_openat,	  .chmod_mode = 0600,
+		  .orig.how.flags =   O_RDWR, .orig.mode  = 0700,
+		  .new.how.flags  = O_RDONLY, .new.mode   = 0500 },
+		{ .open = sys_openat,	  .chmod_mode = 0600,
+		  .orig.how.flags =   O_RDWR, .orig.mode  = 0700,
+		  .new.how.flags  = O_WRONLY, .new.mode   = 0300 },
+
+		/*
+		 * Re-opening with a different mode will always fail (with an obvious
+		 * carve-out for privileged users).
+		 */
+		{ .open = sys_openat,	  .chmod_mode = 0600,
+		  .orig.how.flags = O_RDONLY, .orig.mode  = 0500,
+		  .new.how.flags  = O_WRONLY, .new.mode   = 0300, .new.err = err_access },
+		{ .open = sys_openat,	  .chmod_mode = 0600,
+		  .orig.how.flags = O_WRONLY, .orig.mode  = 0300,
+		  .new.how.flags  = O_RDONLY, .new.mode   = 0500, .new.err = err_access },
+		{ .open = sys_openat,	  .chmod_mode = 0600,
+		  .orig.how.flags = O_RDONLY, .orig.mode  = 0500,
+		  .new.how.flags  =   O_RDWR, .new.mode   = 0700, .new.err = err_access },
+		{ .open = sys_openat,	  .chmod_mode = 0600,
+		  .orig.how.flags = O_WRONLY, .orig.mode  = 0300,
+		  .new.how.flags  =   O_RDWR, .new.mode   = 0700, .new.err = err_access },
+
+		/* Doubly so if they didn't even have permissions at open-time. */
+		{ .open = sys_openat,	  .chmod_mode = 0400,
+		  .orig.how.flags = O_RDONLY, .orig.mode  = 0500,
+		  .new.how.flags  = O_WRONLY, .new.mode   = 0300, .new.err = err_access },
+		{ .open = sys_openat,	  .chmod_mode = 0200,
+		  .orig.how.flags = O_WRONLY, .orig.mode  = 0300,
+		  .new.how.flags  = O_RDONLY, .new.mode   = 0500, .new.err = err_access },
+		{ .open = sys_openat,	  .chmod_mode = 0400,
+		  .orig.how.flags = O_RDONLY, .orig.mode  = 0500,
+		  .new.how.flags  =   O_RDWR, .new.mode   = 0700, .new.err = err_access },
+		{ .open = sys_openat,	  .chmod_mode = 0200,
+		  .orig.how.flags = O_WRONLY, .orig.mode  = 0300,
+		  .new.how.flags  =   O_RDWR, .new.mode   = 0700, .new.err = err_access },
+
+		/* O_PATH re-opens (of ordinary files) will always work. */
+		{ .open = sys_openat,	  .chmod_mode = 0000,
+		  .orig.how.flags =   O_PATH, .orig.mode  = 0070,
+		  .new.how.flags  = O_WRONLY, .new.mode   = 0300 },
+		{ .open = sys_openat2,  .chmod_mode = 0000,
+		  .orig.how.flags =   O_PATH, .orig.mode  = 0070,
+		  .new.how.flags  = O_WRONLY, .new.mode   = 0300 },
+
+		{ .open = sys_openat,	  .chmod_mode = 0000,
+		  .orig.how.flags =   O_PATH, .orig.mode  = 0070,
+		  .new.how.flags  = O_RDONLY, .new.mode   = 0500 },
+		{ .open = sys_openat2,  .chmod_mode = 0000,
+		  .orig.how.flags =   O_PATH, .orig.mode  = 0070,
+		  .new.how.flags  = O_RDONLY, .new.mode   = 0500 },
+
+		{ .open = sys_openat,	  .chmod_mode = 0000,
+		  .orig.how.flags =   O_PATH, .orig.mode  = 0070,
+		  .new.how.flags  =   O_RDWR, .new.mode   = 0700 },
+		{ .open = sys_openat2,  .chmod_mode = 0000,
+		  .orig.how.flags =   O_PATH, .orig.mode  = 0070,
+		  .new.how.flags  =   O_RDWR, .new.mode   = 0700 },
+
+		/*
+		 * openat2(2) UPGRADE_NO* flags. In the privileged case, the re-open
+		 * will work but the mode will still be scoped to the mode (or'd with
+		 * the open acc_mode).
+		 */
+		{ .open = sys_openat2,  .chmod_mode = 0000,
+		  .orig.how.flags = O_PATH, .orig.mode = 0010,
+		  .orig.how.upgrade_mask = UPGRADE_NOREAD | UPGRADE_NOWRITE,
+		  .new.how.flags  = O_RDONLY, .new.mode   = 0500, .new.err = err_access },
+		{ .open = sys_openat2,  .chmod_mode = 0000,
+		  .orig.how.flags = O_PATH, .orig.mode = 0010,
+		  .orig.how.upgrade_mask = UPGRADE_NOREAD | UPGRADE_NOWRITE,
+		  .new.how.flags  = O_WRONLY, .new.mode   = 0300, .new.err = err_access },
+		{ .open = sys_openat2,  .chmod_mode = 0000,
+		  .orig.how.flags = O_PATH, .orig.mode = 0010,
+		  .orig.how.upgrade_mask = UPGRADE_NOREAD | UPGRADE_NOWRITE,
+		  .new.how.flags  =   O_RDWR, .new.mode   = 0700, .new.err = err_access },
+
+		{ .open = sys_openat2,  .chmod_mode = 0000,
+		  .orig.how.flags = O_PATH, .orig.mode = 0050,
+		  .orig.how.upgrade_mask = UPGRADE_NOWRITE,
+		  .new.how.flags  = O_RDONLY, .new.mode   = 0500 },
+
+		{ .open = sys_openat2,  .chmod_mode = 0000,
+		  .orig.how.flags = O_PATH, .orig.mode = 0030,
+		  .orig.how.upgrade_mask = UPGRADE_NOREAD,
+		  .new.how.flags  = O_WRONLY, .new.mode   = 0300 },
+
+		{ .open = sys_openat2,  .chmod_mode = 0000,
+		  .orig.how.flags = O_PATH, .orig.mode = 0030,
+		  .orig.how.upgrade_mask = UPGRADE_NOREAD,
+		  .new.how.flags  = O_RDONLY, .new.mode   = 0500, .new.err = err_access },
+		{ .open = sys_openat2,  .chmod_mode = 0000,
+		  .orig.how.flags = O_PATH, .orig.mode = 0050,
+		  .orig.how.upgrade_mask = UPGRADE_NOWRITE,
+		  .new.how.flags  = O_WRONLY, .new.mode   = 0300, .new.err = err_access },
+		{ .open = sys_openat2,  .chmod_mode = 0000,
+		  .orig.how.flags = O_PATH, .orig.mode = 0030,
+		  .orig.how.upgrade_mask = UPGRADE_NOREAD,
+		  .new.how.flags  =   O_RDWR, .new.mode   = 0700, .new.err = err_access },
+		{ .open = sys_openat2,  .chmod_mode = 0000,
+		  .orig.how.flags = O_PATH, .orig.mode = 0050,
+		  .orig.how.upgrade_mask = UPGRADE_NOWRITE,
+		  .new.how.flags  =   O_RDWR, .new.mode   = 0700, .new.err = err_access },
+	};
+
+	BUILD_BUG_ON(ARRAY_LEN(tests) != NUM_REOPEN_TESTS);
+
+	for (int i = 0; i < ARRAY_LEN(tests); i++) {
+		int fd;
+		char *orig_flagset, *new_flagset;
+		struct reopen_test *test = &tests[i];
+		void (*resultfn)(const char *msg, ...) = ksft_test_result_pass;
+
+		E_chmod(tmpfile, test->chmod_mode);
+
+		fd = test->open(AT_FDCWD, tmpfile, &test->orig.how);
+		E_assert(fd >= 0, "open '%s' failed: %m\n", tmpfile);
+
+		/* Make sure that any EACCES we see is not from inode permissions. */
+		E_chmod(tmpfile, 0777);
+
+		if (reopen(fd, test))
+			resultfn = ksft_test_result_fail;
+
+		close(fd);
+
+		new_flagset = openat_flags(test->new.how.flags);
+		if (test->open == sys_openat)
+			orig_flagset = openat_flags(test->orig.how.flags);
+		else if (test->open == sys_openat2)
+			orig_flagset = openat2_flags(&test->orig.how);
+		else
+			ksft_exit_fail_msg("unknown test->open\n");
+
+		resultfn("%sordinary reopen of (orig[%s]=%s, new=%s) chmod=%.3o %s\n",
+			 privileged ? "privileged " : "",
+			 test->open == sys_openat ? "openat" : "openat2",
+			 orig_flagset, new_flagset, test->chmod_mode,
+			 test->new.err < 0 ? strerror(-test->new.err) : "works");
+		fflush(stdout);
+
+		free(new_flagset);
+		free(orig_flagset);
+	}
+
+	unlink(tmpfile);
+}
+
+#define NUM_CLOEXEC_TESTS 1
+
+void test_openat2_cloexec_test(void)
+{
+	void (*resultfn)(const char *msg, ...) = ksft_test_result_pass;
+	struct open_how how = {
+		.flags = O_CLOEXEC | O_PATH | O_DIRECTORY,
+	};
+
+	int fd = sys_openat2(AT_FDCWD, ".", &how);
+	E_assert(fd >= 0, "open '.' failed: %m\n");
+
+	int flags = fcntl(fd, F_GETFD);
+	E_assert(flags >= 0, "F_GETFD failed: %m\n");
+
+	if (!(flags & FD_CLOEXEC))
+		resultfn = ksft_test_result_fail;
+
+	resultfn("openat2(O_CLOEXEC) works as expected\n");
+}
+
+int main(int argc, char **argv)
+{
+	bool privileged;
+
+	ksft_print_header();
+	ksft_set_plan(2 * NUM_REOPEN_TESTS + NUM_CLOEXEC_TESTS);
+	test_openat2_supported();
+
+	/*
+	 * Technically we should be checking CAP_DAC_OVERRIDE, but it's easier to
+	 * just assume that euid=0 has the full capability set.
+	 */
+	privileged = (geteuid() == 0);
+	if (!privileged)
+		ksft_test_result_skip("privileged tests require euid == 0\n");
+	else {
+		test_reopen_ordinary(privileged);
+
+		E_setresuid(65534, 65534, 65534);
+		privileged = (geteuid() == 0);
+	}
+
+	test_reopen_ordinary(privileged);
+	test_openat2_cloexec_test();
+
+	if (ksft_get_fail_cnt() + ksft_get_error_cnt() > 0)
+		ksft_exit_fail();
+	else
+		ksft_exit_pass();
+}
diff --git a/tools/testing/selftests/openat2/rename_attack_test.c b/tools/testing/selftests/openat2/rename_attack_test.c
new file mode 100644
index 000000000000..39b20ea185d5
--- /dev/null
+++ b/tools/testing/selftests/openat2/rename_attack_test.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Author: Aleksa Sarai <cyphar@cyphar.com>
+ * Copyright (C) 2018-2019 SUSE LLC.
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <sched.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/mount.h>
+#include <sys/mman.h>
+#include <sys/prctl.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <syscall.h>
+#include <limits.h>
+#include <unistd.h>
+
+#include "../kselftest.h"
+#include "helpers.h"
+
+/* Construct a test directory with the following structure:
+ *
+ * root/
+ * |-- a/
+ * |   `-- c/
+ * `-- b/
+ */
+int setup_testdir(void)
+{
+	int dfd;
+	char dirname[] = "/tmp/ksft-openat2-rename-attack.XXXXXX";
+
+	/* Make the top-level directory. */
+	if (!mkdtemp(dirname))
+		ksft_exit_fail_msg("setup_testdir: failed to create tmpdir\n");
+	dfd = open(dirname, O_PATH | O_DIRECTORY);
+	if (dfd < 0)
+		ksft_exit_fail_msg("setup_testdir: failed to open tmpdir\n");
+
+	E_mkdirat(dfd, "a", 0755);
+	E_mkdirat(dfd, "b", 0755);
+	E_mkdirat(dfd, "a/c", 0755);
+
+	return dfd;
+}
+
+/* Swap @dirfd/@a and @dirfd/@b constantly. Parent must kill this process. */
+pid_t spawn_attack(int dirfd, char *a, char *b)
+{
+	pid_t child = fork();
+	if (child != 0)
+		return child;
+
+	/* If the parent (the test process) dies, kill ourselves too. */
+	prctl(PR_SET_PDEATHSIG, SIGKILL);
+
+	/* Swap @a and @b. */
+	for (;;)
+		renameat2(dirfd, a, dirfd, b, RENAME_EXCHANGE);
+	exit(1);
+}
+
+#define NUM_RENAME_TESTS 1
+#define ROUNDS 400000
+
+void test_rename_attack(void)
+{
+	int dfd, afd, escaped_count = 0;
+	void (*resultfn)(const char *msg, ...) = ksft_test_result_pass;
+	pid_t child;
+
+	dfd = setup_testdir();
+	afd = openat(dfd, "a", O_PATH);
+	if (afd < 0)
+		ksft_exit_fail_msg("test_rename_attack: failed to open 'a'\n");
+
+	child = spawn_attack(dfd, "a/c", "b");
+
+	for (int i = 0; i < ROUNDS; i++) {
+		int fd;
+		bool failed;
+		struct open_how how = {
+			.flags = O_PATH,
+			.resolve = RESOLVE_IN_ROOT,
+		};
+		char *victim_path = "c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../../c/../..";
+
+		fd = sys_openat2(afd, victim_path, &how);
+		if (fd < 0)
+			failed = (fd != -EXDEV);
+		else
+			failed = !fdequal(fd, afd, NULL);
+
+		escaped_count += failed;
+		close(fd);
+	}
+
+	if (escaped_count > 0)
+		resultfn = ksft_test_result_fail;
+
+	resultfn("rename attack fails (expected 0 breakouts in %d runs, got %d)\n",
+		 ROUNDS, escaped_count);
+
+	/* Should be killed anyway, but might as well make sure. */
+	kill(child, SIGKILL);
+}
+
+int main(int argc, char **argv)
+{
+	ksft_print_header();
+	ksft_set_plan(NUM_RENAME_TESTS);
+	test_openat2_supported();
+
+	test_rename_attack();
+
+	if (ksft_get_fail_cnt() + ksft_get_error_cnt() > 0)
+		ksft_exit_fail();
+	else
+		ksft_exit_pass();
+}
diff --git a/tools/testing/selftests/openat2/resolve_test.c b/tools/testing/selftests/openat2/resolve_test.c
new file mode 100644
index 000000000000..8ef3dbb7edbe
--- /dev/null
+++ b/tools/testing/selftests/openat2/resolve_test.c
@@ -0,0 +1,402 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Author: Aleksa Sarai <cyphar@cyphar.com>
+ * Copyright (C) 2018-2019 SUSE LLC.
+ */
+
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <sched.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/mount.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include "../kselftest.h"
+#include "helpers.h"
+
+/*
+ * Construct a test directory with the following structure:
+ *
+ * root/
+ * |-- procexe -> /proc/self/exe
+ * |-- procroot -> /proc/self/root
+ * |-- root/
+ * |-- mnt/ [mountpoint]
+ * |   |-- self -> ../mnt/
+ * |   `-- absself -> /mnt/
+ * |-- etc/
+ * |   `-- passwd
+ * |-- creatlink -> /newfile3
+ * |-- relsym -> etc/passwd
+ * |-- abssym -> /etc/passwd
+ * |-- abscheeky -> /cheeky
+ * |-- abscheeky -> /cheeky
+ * `-- cheeky/
+ *     |-- absself -> /
+ *     |-- self -> ../../root/
+ *     |-- garbageself -> /../../root/
+ *     |-- passwd -> ../cheeky/../cheeky/../etc/../etc/passwd
+ *     |-- abspasswd -> /../cheeky/../cheeky/../etc/../etc/passwd
+ *     |-- dotdotlink -> ../../../../../../../../../../../../../../etc/passwd
+ *     `-- garbagelink -> /../../../../../../../../../../../../../../etc/passwd
+ */
+int setup_testdir(void)
+{
+	int dfd, tmpfd;
+	char dirname[] = "/tmp/ksft-openat2-testdir.XXXXXX";
+
+	/* Unshare and make /tmp a new directory. */
+	E_unshare(CLONE_NEWNS);
+	E_mount("", "/tmp", "", MS_PRIVATE, "");
+
+	/* Make the top-level directory. */
+	if (!mkdtemp(dirname))
+		ksft_exit_fail_msg("setup_testdir: failed to create tmpdir\n");
+	dfd = open(dirname, O_PATH | O_DIRECTORY);
+	if (dfd < 0)
+		ksft_exit_fail_msg("setup_testdir: failed to open tmpdir\n");
+
+	/* A sub-directory which is actually used for tests. */
+	E_mkdirat(dfd, "root", 0755);
+	tmpfd = openat(dfd, "root", O_PATH | O_DIRECTORY);
+	if (tmpfd < 0)
+		ksft_exit_fail_msg("setup_testdir: failed to open tmpdir\n");
+	close(dfd);
+	dfd = tmpfd;
+
+	E_symlinkat("/proc/self/exe", dfd, "procexe");
+	E_symlinkat("/proc/self/root", dfd, "procroot");
+	E_mkdirat(dfd, "root", 0755);
+
+	/* There is no mountat(2), so use chdir. */
+	E_mkdirat(dfd, "mnt", 0755);
+	E_fchdir(dfd);
+	E_mount("tmpfs", "./mnt", "tmpfs", MS_NOSUID | MS_NODEV, "");
+	E_symlinkat("../mnt/", dfd, "mnt/self");
+	E_symlinkat("/mnt/", dfd, "mnt/absself");
+
+	E_mkdirat(dfd, "etc", 0755);
+	E_touchat(dfd, "etc/passwd");
+
+	E_symlinkat("/newfile3", dfd, "creatlink");
+	E_symlinkat("etc/passwd", dfd, "relsym");
+	E_symlinkat("/etc/passwd", dfd, "abssym");
+	E_symlinkat("/cheeky", dfd, "abscheeky");
+
+	E_mkdirat(dfd, "cheeky", 0755);
+
+	E_symlinkat("/", dfd, "cheeky/absself");
+	E_symlinkat("../../root/", dfd, "cheeky/self");
+	E_symlinkat("/../../root/", dfd, "cheeky/garbageself");
+
+	E_symlinkat("../cheeky/../etc/../etc/passwd", dfd, "cheeky/passwd");
+	E_symlinkat("/../cheeky/../etc/../etc/passwd", dfd, "cheeky/abspasswd");
+
+	E_symlinkat("../../../../../../../../../../../../../../etc/passwd",
+		    dfd, "cheeky/dotdotlink");
+	E_symlinkat("/../../../../../../../../../../../../../../etc/passwd",
+		    dfd, "cheeky/garbagelink");
+
+	return dfd;
+}
+
+struct basic_test {
+	const char *dir;
+	const char *path;
+	struct open_how how;
+	bool pass;
+	union {
+		int err;
+		const char *path;
+	} out;
+};
+
+#define NUM_OPENAT2_OPATH_TESTS 84
+
+void test_openat2_opath_tests(void)
+{
+	int rootfd;
+	char *procselfexe;
+
+	E_asprintf(&procselfexe, "/proc/%d/exe", getpid());
+	rootfd = setup_testdir();
+
+	struct basic_test tests[] = {
+		/** RESOLVE_BENEATH **/
+		/* Attempts to cross dirfd should be blocked. */
+		{ .path = "/",			.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "cheeky/absself",	.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "abscheeky/absself",	.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "..",			.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "../root/",		.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "cheeky/self",	.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "abscheeky/self",	.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "cheeky/garbageself",	.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "abscheeky/garbageself", .how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		/* Only relative paths that stay inside dirfd should work. */
+		{ .path = "root",		.how.resolve = RESOLVE_BENEATH,
+		  .out.path = "root",		.pass = true },
+		{ .path = "etc",		.how.resolve = RESOLVE_BENEATH,
+		  .out.path = "etc",		.pass = true },
+		{ .path = "etc/passwd",		.how.resolve = RESOLVE_BENEATH,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "relsym",		.how.resolve = RESOLVE_BENEATH,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "cheeky/passwd",	.how.resolve = RESOLVE_BENEATH,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "abscheeky/passwd",	.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "abssym",		.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "/etc/passwd",	.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "cheeky/abspasswd",	.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "abscheeky/abspasswd", .how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		/* Tricky paths should fail. */
+		{ .path = "cheeky/dotdotlink",	.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "abscheeky/dotdotlink", .how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "cheeky/garbagelink",	.how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "abscheeky/garbagelink", .how.resolve = RESOLVE_BENEATH,
+		  .out.err = -EXDEV,		.pass = false },
+
+		/** RESOLVE_IN_ROOT **/
+		/* All attempts to cross the dirfd will be scoped-to-root. */
+		{ .path = "/",			.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = NULL,		.pass = true },
+		{ .path = "cheeky/absself",	.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = NULL,		.pass = true },
+		{ .path = "abscheeky/absself",	.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = NULL,		.pass = true },
+		{ .path = "..",			.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = NULL,		.pass = true },
+		{ .path = "../root/",		.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "root",		.pass = true },
+		{ .path = "../root/",		.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "root",		.pass = true },
+		{ .path = "cheeky/self",	.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "root",		.pass = true },
+		{ .path = "cheeky/garbageself",	.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "root",		.pass = true },
+		{ .path = "abscheeky/garbageself", .how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "root",		.pass = true },
+		{ .path = "root",		.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "root",		.pass = true },
+		{ .path = "etc",		.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc",		.pass = true },
+		{ .path = "etc/passwd",		.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "relsym",		.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "cheeky/passwd",	.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "abscheeky/passwd",	.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "abssym",		.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "/etc/passwd",	.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "cheeky/abspasswd",	.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "abscheeky/abspasswd", .how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "cheeky/dotdotlink",	.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "abscheeky/dotdotlink", .how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "/../../../../abscheeky/dotdotlink", .how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "cheeky/garbagelink",	.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "abscheeky/garbagelink", .how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		{ .path = "/../../../../abscheeky/garbagelink", .how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "etc/passwd",	.pass = true },
+		/* O_CREAT should handle trailing symlinks correctly. */
+		{ .path = "newfile1",		.how.flags = O_CREAT,
+						.how.mode = 0700,
+						.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "newfile1",	.pass = true },
+		{ .path = "/newfile2",		.how.flags = O_CREAT,
+						.how.mode = 0700,
+						.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "newfile2",	.pass = true },
+		{ .path = "/creatlink",		.how.flags = O_CREAT,
+						.how.mode = 0700,
+						.how.resolve = RESOLVE_IN_ROOT,
+		  .out.path = "newfile3",	.pass = true },
+
+		/** RESOLVE_NO_XDEV **/
+		/* Crossing *down* into a mountpoint is disallowed. */
+		{ .path = "mnt",		.how.resolve = RESOLVE_NO_XDEV,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "mnt/",		.how.resolve = RESOLVE_NO_XDEV,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "mnt/.",		.how.resolve = RESOLVE_NO_XDEV,
+		  .out.err = -EXDEV,		.pass = false },
+		/* Crossing *up* out of a mountpoint is disallowed. */
+		{ .dir = "mnt", .path = ".",	.how.resolve = RESOLVE_NO_XDEV,
+		  .out.path = "mnt",		.pass = true },
+		{ .dir = "mnt", .path = "..",	.how.resolve = RESOLVE_NO_XDEV,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .dir = "mnt", .path = "../mnt", .how.resolve = RESOLVE_NO_XDEV,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .dir = "mnt", .path = "self",	.how.resolve = RESOLVE_NO_XDEV,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .dir = "mnt", .path = "absself", .how.resolve = RESOLVE_NO_XDEV,
+		  .out.err = -EXDEV,		.pass = false },
+		/* Jumping to "/" is ok, but later components cannot cross. */
+		{ .dir = "mnt", .path = "/",	.how.resolve = RESOLVE_NO_XDEV,
+		  .out.path = "/",		.pass = true },
+		{ .dir = "/", .path = "/",	.how.resolve = RESOLVE_NO_XDEV,
+		  .out.path = "/",		.pass = true },
+		{ .path = "/proc/1",		.how.resolve = RESOLVE_NO_XDEV,
+		  .out.err = -EXDEV,		.pass = false },
+		{ .path = "/tmp",		.how.resolve = RESOLVE_NO_XDEV,
+		  .out.err = -EXDEV,		.pass = false },
+
+		/** RESOLVE_NO_MAGICLINKS **/
+		/* Regular symlinks should work. */
+		{ .path = "relsym",		.how.resolve = RESOLVE_NO_MAGICLINKS,
+		  .out.path = "etc/passwd",	.pass = true },
+		/* Magic-links should not work. */
+		{ .path = "procexe",		.how.resolve = RESOLVE_NO_MAGICLINKS,
+		  .out.err = -ELOOP,		.pass = false },
+		{ .path = "/proc/self/exe",	.how.resolve = RESOLVE_NO_MAGICLINKS,
+		  .out.err = -ELOOP,		.pass = false },
+		{ .path = "procroot/etc",	.how.resolve = RESOLVE_NO_MAGICLINKS,
+		  .out.err = -ELOOP,		.pass = false },
+		{ .path = "/proc/self/root/etc", .how.resolve = RESOLVE_NO_MAGICLINKS,
+		  .out.err = -ELOOP,		.pass = false },
+		{ .path = "/proc/self/root/etc", .how.flags = O_NOFOLLOW,
+						 .how.resolve = RESOLVE_NO_MAGICLINKS,
+		  .out.err = -ELOOP,		.pass = false },
+		{ .path = "/proc/self/exe",	.how.flags = O_NOFOLLOW,
+						.how.resolve = RESOLVE_NO_MAGICLINKS,
+		  .out.path = procselfexe,	.pass = true },
+
+		/** RESOLVE_NO_SYMLINKS **/
+		/* Normal paths should work. */
+		{ .path = ".",			.how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.path = NULL,		.pass = true },
+		{ .path = "root",		.how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.path = "root",		.pass = true },
+		{ .path = "etc",		.how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.path = "etc",		.pass = true },
+		{ .path = "etc/passwd",		.how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.path = "etc/passwd",	.pass = true },
+		/* Regular symlinks are blocked. */
+		{ .path = "relsym",		.how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.err = -ELOOP,		.pass = false },
+		{ .path = "abssym",		.how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.err = -ELOOP,		.pass = false },
+		{ .path = "cheeky/garbagelink",	.how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.err = -ELOOP,		.pass = false },
+		{ .path = "abscheeky/garbagelink", .how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.err = -ELOOP,		.pass = false },
+		{ .path = "abscheeky/absself",	.how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.err = -ELOOP,		.pass = false },
+		/* Trailing symlinks with NO_FOLLOW. */
+		{ .path = "relsym",		.how.flags = O_NOFOLLOW,
+						.how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.path = "relsym",		.pass = true },
+		{ .path = "abssym",		.how.flags = O_NOFOLLOW,
+						.how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.path = "abssym",		.pass = true },
+		{ .path = "cheeky/garbagelink",	.how.flags = O_NOFOLLOW,
+						.how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.path = "cheeky/garbagelink", .pass = true },
+		{ .path = "abscheeky/garbagelink", .how.flags = O_NOFOLLOW,
+						   .how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.err = -ELOOP,		.pass = false },
+		{ .path = "abscheeky/absself",	.how.flags = O_NOFOLLOW,
+						.how.resolve = RESOLVE_NO_SYMLINKS,
+		  .out.err = -ELOOP,		.pass = false },
+	};
+
+	BUILD_BUG_ON(ARRAY_LEN(tests) != NUM_OPENAT2_OPATH_TESTS);
+
+	for (int i = 0; i < ARRAY_LEN(tests); i++) {
+		int dfd, fd;
+		bool failed;
+		void (*resultfn)(const char *msg, ...) = ksft_test_result_pass;
+		struct basic_test *test = &tests[i];
+		char *flagstr;
+
+		/* Auto-set O_PATH. */
+		if (!(test->how.flags & O_CREAT))
+			test->how.flags |= O_PATH;
+		flagstr = openat2_flags(&test->how);
+
+		if (test->dir)
+			dfd = openat(rootfd, test->dir, O_PATH | O_DIRECTORY);
+		else
+			dfd = dup(rootfd);
+		if (dfd < 0) {
+			resultfn = ksft_test_result_error;
+			goto next;
+		}
+
+		fd = sys_openat2(dfd, test->path, &test->how);
+		if (test->pass)
+			failed = (fd < 0 || !fdequal(fd, rootfd, test->out.path));
+		else
+			failed = (fd != test->out.err);
+		if (fd >= 0)
+			close(fd);
+		close(dfd);
+
+		if (failed)
+			resultfn = ksft_test_result_fail;
+
+next:
+		if (test->pass)
+			resultfn("openat2(root[%s], %s, %s) ==> %s\n",
+				 test->dir ?: ".", test->path, flagstr,
+				 test->out.path ?: ".");
+		else
+			resultfn("openat2(root[%s], %s, %s) ==> %d (%s)\n",
+				 test->dir ?: ".", test->path, flagstr,
+				 test->out.err, strerror(-test->out.err));
+		fflush(stdout);
+
+		free(flagstr);
+	}
+
+	free(procselfexe);
+	close(rootfd);
+}
+
+int main(int argc, char **argv)
+{
+	ksft_print_header();
+	ksft_set_plan(NUM_OPENAT2_OPATH_TESTS);
+	test_openat2_supported();
+
+	/* NOTE: We should be checking for CAP_SYS_ADMIN here... */
+	if (geteuid() != 0)
+		ksft_exit_skip("openat2(2) tests require euid == 0\n");
+
+	test_openat2_opath_tests();
+
+	if (ksft_get_fail_cnt() + ksft_get_error_cnt() > 0)
+		ksft_exit_fail();
+	else
+		ksft_exit_pass();
+}
-- 
2.22.0



_______________________________________________
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related

* [PATCH RESEND v11 7/8] open: openat2(2) syscall
From: Aleksa Sarai @ 2019-08-20  3:34 UTC (permalink / raw)
  To: Al Viro, Jeff Layton, J. Bruce Fields, Arnd Bergmann,
	David Howells, Shuah Khan, Shuah Khan
  Cc: linux-ia64, linux-sh, Alexei Starovoitov, Oleg Nesterov,
	linux-kselftest, sparclinux, linux-arch, linux-s390,
	Tycho Andersen, Aleksa Sarai, linux-arm-kernel, linux-mips,
	linux-xtensa, Kees Cook, Jann Horn, linuxppc-dev, Aleksa Sarai,
	Andy Lutomirski, David Drysdale, Christian Brauner, linux-parisc,
	linux-m68k, linux-api, Chanho Min, linux-kernel, Eric Biederman,
	linux-alpha, linux-fsdevel, Andrew Morton, Linus Torvalds,
	containers
In-Reply-To: <20190820033406.29796-1-cyphar@cyphar.com>

The most obvious syscall to add support for the new LOOKUP_* scoping
flags would be openat(2). However, there are a few reasons why this is
not the best course of action:

 * The new LOOKUP_* flags are intended to be security features, and
   openat(2) will silently ignore all unknown flags. This means that
   users would need to avoid foot-gunning themselves constantly when
   using this interface if it were part of openat(2). This can be fixed
   by having userspace libraries handle this for users[1], but should be
   avoided if possible.

 * Resolution scoping feels like a different operation to the existing
   O_* flags. And since openat(2) has limited flag space, it seems to be
   quite wasteful to clutter it with 5 flags that are all
   resolution-related. Arguably O_NOFOLLOW is also a resolution flag but
   its entire purpose is to error out if you encounter a trailing
   symlink -- not to scope resolution.

 * Other systems would be able to reimplement this syscall allowing for
   cross-OS standardisation rather than being hidden amongst O_* flags
   which may result in it not being used by all the parties that might
   want to use it (file servers, web servers, container runtimes, etc).

 * It gives us the opportunity to iterate on the O_PATH interface. In
   particular, the new @how->upgrade_mask field for fd re-opening is
   only possible because we have a clean slate without needing to re-use
   the ACC_MODE flag design nor the existing openat(2) @mode semantics.

To this end, we introduce the openat2(2) syscall. It provides all of the
features of openat(2) through the @how->flags argument, but also
also provides a new @how->resolve argument which exposes RESOLVE_* flags
that map to our new LOOKUP_* flags. It also eliminates the long-standing
ugliness of variadic-open(2) by embedding it in a struct.

In order to allow for userspace to lock down their usage of file
descriptor re-opening, openat2(2) has the ability for users to disallow
certain re-opening modes through @how->upgrade_mask. At the moment,
there is no UPGRADE_NOEXEC. The open_how struct is padded to 64 bytes
for future extensions (all of the reserved bits must be zeroed).

[1]: https://github.com/openSUSE/libpathrs

Suggested-by: Christian Brauner <christian@brauner.io>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
 arch/alpha/kernel/syscalls/syscall.tbl      |   1 +
 arch/arm/tools/syscall.tbl                  |   1 +
 arch/arm64/include/asm/unistd.h             |   2 +-
 arch/arm64/include/asm/unistd32.h           |   2 +
 arch/ia64/kernel/syscalls/syscall.tbl       |   1 +
 arch/m68k/kernel/syscalls/syscall.tbl       |   1 +
 arch/microblaze/kernel/syscalls/syscall.tbl |   1 +
 arch/mips/kernel/syscalls/syscall_n32.tbl   |   1 +
 arch/mips/kernel/syscalls/syscall_n64.tbl   |   1 +
 arch/mips/kernel/syscalls/syscall_o32.tbl   |   1 +
 arch/parisc/kernel/syscalls/syscall.tbl     |   1 +
 arch/powerpc/kernel/syscalls/syscall.tbl    |   1 +
 arch/s390/kernel/syscalls/syscall.tbl       |   1 +
 arch/sh/kernel/syscalls/syscall.tbl         |   1 +
 arch/sparc/kernel/syscalls/syscall.tbl      |   1 +
 arch/x86/entry/syscalls/syscall_32.tbl      |   1 +
 arch/x86/entry/syscalls/syscall_64.tbl      |   1 +
 arch/xtensa/kernel/syscalls/syscall.tbl     |   1 +
 fs/open.c                                   | 106 ++++++++++++++++----
 include/linux/fcntl.h                       |  15 ++-
 include/linux/fs.h                          |   4 +-
 include/linux/syscalls.h                    |  17 +++-
 include/uapi/asm-generic/unistd.h           |   5 +-
 include/uapi/linux/fcntl.h                  |  42 ++++++++
 24 files changed, 179 insertions(+), 30 deletions(-)

diff --git a/arch/alpha/kernel/syscalls/syscall.tbl b/arch/alpha/kernel/syscalls/syscall.tbl
index 728fe028c02c..9f374f7d9514 100644
--- a/arch/alpha/kernel/syscalls/syscall.tbl
+++ b/arch/alpha/kernel/syscalls/syscall.tbl
@@ -475,3 +475,4 @@
 543	common	fspick				sys_fspick
 544	common	pidfd_open			sys_pidfd_open
 # 545 reserved for clone3
+547	common	openat2				sys_openat2
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index 6da7dc4d79cc..4ba54bc7e19a 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -449,3 +449,4 @@
 433	common	fspick				sys_fspick
 434	common	pidfd_open			sys_pidfd_open
 435	common	clone3				sys_clone3
+437	common	openat2				sys_openat2
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index 2629a68b8724..8aa00ccb0b96 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -38,7 +38,7 @@
 #define __ARM_NR_compat_set_tls		(__ARM_NR_COMPAT_BASE + 5)
 #define __ARM_NR_COMPAT_END		(__ARM_NR_COMPAT_BASE + 0x800)
 
-#define __NR_compat_syscalls		436
+#define __NR_compat_syscalls		438
 #endif
 
 #define __ARCH_WANT_SYS_CLONE
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index 94ab29cf4f00..57f6f592d460 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -879,6 +879,8 @@ __SYSCALL(__NR_fspick, sys_fspick)
 __SYSCALL(__NR_pidfd_open, sys_pidfd_open)
 #define __NR_clone3 435
 __SYSCALL(__NR_clone3, sys_clone3)
+#define __NR_openat2 437
+__SYSCALL(__NR_openat2, sys_openat2)
 
 /*
  * Please add new compat syscalls above this comment and update
diff --git a/arch/ia64/kernel/syscalls/syscall.tbl b/arch/ia64/kernel/syscalls/syscall.tbl
index 36d5faf4c86c..8d36f2e2dc89 100644
--- a/arch/ia64/kernel/syscalls/syscall.tbl
+++ b/arch/ia64/kernel/syscalls/syscall.tbl
@@ -356,3 +356,4 @@
 433	common	fspick				sys_fspick
 434	common	pidfd_open			sys_pidfd_open
 # 435 reserved for clone3
+437	common	openat2				sys_openat2
diff --git a/arch/m68k/kernel/syscalls/syscall.tbl b/arch/m68k/kernel/syscalls/syscall.tbl
index a88a285a0e5f..2559925f1924 100644
--- a/arch/m68k/kernel/syscalls/syscall.tbl
+++ b/arch/m68k/kernel/syscalls/syscall.tbl
@@ -435,3 +435,4 @@
 433	common	fspick				sys_fspick
 434	common	pidfd_open			sys_pidfd_open
 # 435 reserved for clone3
+437	common	openat2				sys_openat2
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index 09b0cd7dab0a..c04385e60833 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -441,3 +441,4 @@
 433	common	fspick				sys_fspick
 434	common	pidfd_open			sys_pidfd_open
 435	common	clone3				sys_clone3
+437	common	openat2				sys_openat2
diff --git a/arch/mips/kernel/syscalls/syscall_n32.tbl b/arch/mips/kernel/syscalls/syscall_n32.tbl
index c9c879ec9b6d..ba06cae655c6 100644
--- a/arch/mips/kernel/syscalls/syscall_n32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n32.tbl
@@ -374,3 +374,4 @@
 433	n32	fspick				sys_fspick
 434	n32	pidfd_open			sys_pidfd_open
 # 435 reserved for clone3
+437	n32	openat2				sys_openat2
diff --git a/arch/mips/kernel/syscalls/syscall_n64.tbl b/arch/mips/kernel/syscalls/syscall_n64.tbl
index bbce9159caa1..0f3de320ae51 100644
--- a/arch/mips/kernel/syscalls/syscall_n64.tbl
+++ b/arch/mips/kernel/syscalls/syscall_n64.tbl
@@ -350,3 +350,4 @@
 433	n64	fspick				sys_fspick
 434	n64	pidfd_open			sys_pidfd_open
 # 435 reserved for clone3
+437	n64	openat2				sys_openat2
diff --git a/arch/mips/kernel/syscalls/syscall_o32.tbl b/arch/mips/kernel/syscalls/syscall_o32.tbl
index 9653591428ec..f108464d09a3 100644
--- a/arch/mips/kernel/syscalls/syscall_o32.tbl
+++ b/arch/mips/kernel/syscalls/syscall_o32.tbl
@@ -423,3 +423,4 @@
 433	o32	fspick				sys_fspick
 434	o32	pidfd_open			sys_pidfd_open
 # 435 reserved for clone3
+437	o32	openat2				sys_openat2			sys_openat2
diff --git a/arch/parisc/kernel/syscalls/syscall.tbl b/arch/parisc/kernel/syscalls/syscall.tbl
index 670d1371aca1..45ddc4485844 100644
--- a/arch/parisc/kernel/syscalls/syscall.tbl
+++ b/arch/parisc/kernel/syscalls/syscall.tbl
@@ -432,3 +432,4 @@
 433	common	fspick				sys_fspick
 434	common	pidfd_open			sys_pidfd_open
 435	common	clone3				sys_clone3_wrapper
+437	common	openat2				sys_openat2
diff --git a/arch/powerpc/kernel/syscalls/syscall.tbl b/arch/powerpc/kernel/syscalls/syscall.tbl
index 43f736ed47f2..a8b5ecb5b602 100644
--- a/arch/powerpc/kernel/syscalls/syscall.tbl
+++ b/arch/powerpc/kernel/syscalls/syscall.tbl
@@ -517,3 +517,4 @@
 433	common	fspick				sys_fspick
 434	common	pidfd_open			sys_pidfd_open
 435	nospu	clone3				ppc_clone3
+437	common	openat2				sys_openat2
diff --git a/arch/s390/kernel/syscalls/syscall.tbl b/arch/s390/kernel/syscalls/syscall.tbl
index 3054e9c035a3..16b571c06161 100644
--- a/arch/s390/kernel/syscalls/syscall.tbl
+++ b/arch/s390/kernel/syscalls/syscall.tbl
@@ -438,3 +438,4 @@
 433  common	fspick			sys_fspick			sys_fspick
 434  common	pidfd_open		sys_pidfd_open			sys_pidfd_open
 435  common	clone3			sys_clone3			sys_clone3
+437  common	openat2			sys_openat2			sys_openat2
diff --git a/arch/sh/kernel/syscalls/syscall.tbl b/arch/sh/kernel/syscalls/syscall.tbl
index b5ed26c4c005..a7185cc18626 100644
--- a/arch/sh/kernel/syscalls/syscall.tbl
+++ b/arch/sh/kernel/syscalls/syscall.tbl
@@ -438,3 +438,4 @@
 433	common	fspick				sys_fspick
 434	common	pidfd_open			sys_pidfd_open
 # 435 reserved for clone3
+437	common	openat2				sys_openat2
diff --git a/arch/sparc/kernel/syscalls/syscall.tbl b/arch/sparc/kernel/syscalls/syscall.tbl
index 8c8cc7537fb2..b11c19552022 100644
--- a/arch/sparc/kernel/syscalls/syscall.tbl
+++ b/arch/sparc/kernel/syscalls/syscall.tbl
@@ -481,3 +481,4 @@
 433	common	fspick				sys_fspick
 434	common	pidfd_open			sys_pidfd_open
 # 435 reserved for clone3
+437	common	openat2			sys_openat2
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index c00019abd076..dfa1dc5c8587 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -440,3 +440,4 @@
 433	i386	fspick			sys_fspick			__ia32_sys_fspick
 434	i386	pidfd_open		sys_pidfd_open			__ia32_sys_pidfd_open
 435	i386	clone3			sys_clone3			__ia32_sys_clone3
+437	i386	openat2			sys_openat2			__ia32_sys_openat2
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index c29976eca4a8..9035647ef236 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -357,6 +357,7 @@
 433	common	fspick			__x64_sys_fspick
 434	common	pidfd_open		__x64_sys_pidfd_open
 435	common	clone3			__x64_sys_clone3/ptregs
+437	common	openat2			__x64_sys_openat2
 
 #
 # x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 25f4de729a6d..f0a68013c038 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -406,3 +406,4 @@
 433	common	fspick				sys_fspick
 434	common	pidfd_open			sys_pidfd_open
 435	common	clone3				sys_clone3
+437	common	openat2				sys_openat2
diff --git a/fs/open.c b/fs/open.c
index 310b896eecf0..0f050b5e6921 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -947,19 +947,29 @@ struct file *open_with_fake_path(const struct path *path, int flags,
 }
 EXPORT_SYMBOL(open_with_fake_path);
 
-static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
+static inline int build_open_flags(const struct open_how *how,
+				   struct open_flags *op)
 {
+	int flags = how->flags;
 	int lookup_flags = 0;
+	int opath_mask = 0;
 	int acc_mode = ACC_MODE(flags);
 
 	/*
-	 * Clear out all open flags we don't know about so that we don't report
-	 * them in fcntl(F_GETFD) or similar interfaces.
+	 * Older syscalls still clear these bits before calling
+	 * build_open_flags(), but openat2(2) checks all its arguments.
 	 */
-	flags &= VALID_OPEN_FLAGS;
+	if (flags & ~VALID_OPEN_FLAGS)
+		return -EINVAL;
+	if (how->resolve & ~VALID_RESOLVE_FLAGS)
+		return -EINVAL;
+	if (!(how->flags & (O_PATH | O_CREAT | __O_TMPFILE)) && how->mode != 0)
+		return -EINVAL;
+	if (memchr_inv(how->reserved, 0, sizeof(how->reserved)))
+		return -EINVAL;
 
 	if (flags & (O_CREAT | __O_TMPFILE))
-		op->mode = (mode & S_IALLUGO) | S_IFREG;
+		op->mode = (how->mode & S_IALLUGO) | S_IFREG;
 	else
 		op->mode = 0;
 
@@ -987,6 +997,14 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
 		 */
 		flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
 		acc_mode = 0;
+
+		/* Allow userspace to restrict the re-opening of O_PATH fds. */
+		if (how->upgrade_mask & ~VALID_UPGRADE_FLAGS)
+			return -EINVAL;
+		if (!(how->upgrade_mask & UPGRADE_NOREAD))
+			opath_mask |= FMODE_PATH_READ;
+		if (!(how->upgrade_mask & UPGRADE_NOWRITE))
+			opath_mask |= FMODE_PATH_WRITE;
 	}
 
 	op->open_flag = flags;
@@ -1002,8 +1020,7 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
 
 	op->acc_mode = acc_mode;
 	op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
-	/* For O_PATH backwards-compatibility we default to an all-set mask. */
-	op->opath_mask = FMODE_PATH_READ | FMODE_PATH_WRITE;
+	op->opath_mask = opath_mask;
 
 	if (flags & O_CREAT) {
 		op->intent |= LOOKUP_CREATE;
@@ -1017,6 +1034,18 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
 		lookup_flags |= LOOKUP_FOLLOW;
 	if (flags & O_EMPTYPATH)
 		lookup_flags |= LOOKUP_EMPTY;
+
+	if (how->resolve & RESOLVE_NO_XDEV)
+		lookup_flags |= LOOKUP_NO_XDEV;
+	if (how->resolve & RESOLVE_NO_MAGICLINKS)
+		lookup_flags |= LOOKUP_NO_MAGICLINKS;
+	if (how->resolve & RESOLVE_NO_SYMLINKS)
+		lookup_flags |= LOOKUP_NO_SYMLINKS;
+	if (how->resolve & RESOLVE_BENEATH)
+		lookup_flags |= LOOKUP_BENEATH;
+	if (how->resolve & RESOLVE_IN_ROOT)
+		lookup_flags |= LOOKUP_IN_ROOT;
+
 	op->lookup_flags = lookup_flags;
 	return 0;
 }
@@ -1035,8 +1064,14 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
 struct file *file_open_name(struct filename *name, int flags, umode_t mode)
 {
 	struct open_flags op;
-	int err = build_open_flags(flags, mode, &op);
-	return err ? ERR_PTR(err) : do_filp_open(AT_FDCWD, name, &op);
+	struct open_how how = {
+		.flags = flags & VALID_OPEN_FLAGS,
+		.mode = OPENHOW_MODE(flags, mode),
+	};
+	int err = build_open_flags(&how, &op);
+	if (err)
+		return ERR_PTR(err);
+	return do_filp_open(AT_FDCWD, name, &op);
 }
 
 /**
@@ -1067,17 +1102,22 @@ struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
 			    const char *filename, int flags, umode_t mode)
 {
 	struct open_flags op;
-	int err = build_open_flags(flags, mode, &op);
+	struct open_how how = {
+		.flags = flags & VALID_OPEN_FLAGS,
+		.mode = OPENHOW_MODE(flags, mode),
+	};
+	int err = build_open_flags(&how, &op);
 	if (err)
 		return ERR_PTR(err);
 	return do_file_open_root(dentry, mnt, filename, &op);
 }
 EXPORT_SYMBOL(file_open_root);
 
-long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
+long do_sys_open(int dfd, const char __user *filename,
+		 struct open_how *how)
 {
 	struct open_flags op;
-	int fd = build_open_flags(flags, mode, &op);
+	int fd = build_open_flags(how, &op);
 	int empty = 0;
 	struct filename *tmp;
 
@@ -1090,7 +1130,7 @@ long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
 	if (!empty)
 		op.open_flag &= ~O_EMPTYPATH;
 
-	fd = get_unused_fd_flags(flags);
+	fd = get_unused_fd_flags(how->flags);
 	if (fd >= 0) {
 		struct file *f = do_filp_open(dfd, tmp, &op);
 		if (IS_ERR(f)) {
@@ -1107,19 +1147,35 @@ long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
 
 SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
 {
-	if (force_o_largefile())
-		flags |= O_LARGEFILE;
-
-	return do_sys_open(AT_FDCWD, filename, flags, mode);
+	return ksys_open(filename, flags, mode);
 }
 
 SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
 		umode_t, mode)
 {
+	struct open_how how = {
+		.flags = flags & VALID_OPEN_FLAGS,
+		.mode = OPENHOW_MODE(flags, mode),
+	};
+
+	if (force_o_largefile())
+		how.flags |= O_LARGEFILE;
+
+	return do_sys_open(dfd, filename, &how);
+}
+
+SYSCALL_DEFINE3(openat2, int, dfd, const char __user *, filename,
+		const struct open_how __user *, how)
+{
+	struct open_how tmp;
+
+	if (copy_from_user(&tmp, how, sizeof(tmp)))
+		return -EFAULT;
+
 	if (force_o_largefile())
-		flags |= O_LARGEFILE;
+		tmp.flags |= O_LARGEFILE;
 
-	return do_sys_open(dfd, filename, flags, mode);
+	return do_sys_open(dfd, filename, &tmp);
 }
 
 #ifdef CONFIG_COMPAT
@@ -1129,7 +1185,11 @@ SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
  */
 COMPAT_SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
 {
-	return do_sys_open(AT_FDCWD, filename, flags, mode);
+	struct open_how how = {
+		.flags = flags & VALID_OPEN_FLAGS,
+		.mode = OPENHOW_MODE(flags, mode),
+	};
+	return do_sys_open(AT_FDCWD, filename, &how);
 }
 
 /*
@@ -1138,7 +1198,11 @@ COMPAT_SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t,
  */
 COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, umode_t, mode)
 {
-	return do_sys_open(dfd, filename, flags, mode);
+	struct open_how how = {
+		.flags = flags & VALID_OPEN_FLAGS,
+		.mode = OPENHOW_MODE(flags, mode),
+	};
+	return do_sys_open(dfd, filename, &how);
 }
 #endif
 
diff --git a/include/linux/fcntl.h b/include/linux/fcntl.h
index 2868ae6c8fc1..f7f378e1f43c 100644
--- a/include/linux/fcntl.h
+++ b/include/linux/fcntl.h
@@ -4,13 +4,26 @@
 
 #include <uapi/linux/fcntl.h>
 
-/* list of all valid flags for the open/openat flags argument: */
+/* Should open_how.mode be set for older syscalls wrappers? */
+#define OPENHOW_MODE(flags, mode) \
+	(((flags) & (O_CREAT | __O_TMPFILE)) ? (mode) : 0)
+
+/* List of all valid flags for the open/openat flags argument: */
 #define VALID_OPEN_FLAGS \
 	(O_RDONLY | O_WRONLY | O_RDWR | O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC | \
 	 O_APPEND | O_NDELAY | O_NONBLOCK | O_NDELAY | __O_SYNC | O_DSYNC | \
 	 FASYNC	| O_DIRECT | O_LARGEFILE | O_DIRECTORY | O_NOFOLLOW | \
 	 O_NOATIME | O_CLOEXEC | O_PATH | __O_TMPFILE | O_EMPTYPATH)
 
+/* List of all valid flags for the how->upgrade_mask argument: */
+#define VALID_UPGRADE_FLAGS \
+	(UPGRADE_NOWRITE | UPGRADE_NOREAD)
+
+/* List of all valid flags for the how->resolve argument: */
+#define VALID_RESOLVE_FLAGS \
+	(RESOLVE_NO_XDEV | RESOLVE_NO_MAGICLINKS | RESOLVE_NO_SYMLINKS | \
+	 RESOLVE_BENEATH | RESOLVE_IN_ROOT)
+
 #ifndef force_o_largefile
 #define force_o_largefile() (!IS_ENABLED(CONFIG_ARCH_32BIT_OFF_T))
 #endif
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a9ad596b28e2..135e4fa773fc 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2498,8 +2498,8 @@ extern int do_truncate(struct dentry *, loff_t start, unsigned int time_attrs,
 		       struct file *filp);
 extern int vfs_fallocate(struct file *file, int mode, loff_t offset,
 			loff_t len);
-extern long do_sys_open(int dfd, const char __user *filename, int flags,
-			umode_t mode);
+extern long do_sys_open(int dfd, const char __user *filename,
+			struct open_how *how);
 extern struct file *file_open_name(struct filename *, int, umode_t);
 extern struct file *filp_open(const char *, int, umode_t);
 extern struct file *file_open_root(struct dentry *, struct vfsmount *,
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 88145da7d140..a4f2f135001e 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -69,6 +69,7 @@ struct rseq;
 union bpf_attr;
 struct io_uring_params;
 struct clone_args;
+struct open_how;
 
 #include <linux/types.h>
 #include <linux/aio_abi.h>
@@ -439,6 +440,8 @@ asmlinkage long sys_fchownat(int dfd, const char __user *filename, uid_t user,
 asmlinkage long sys_fchown(unsigned int fd, uid_t user, gid_t group);
 asmlinkage long sys_openat(int dfd, const char __user *filename, int flags,
 			   umode_t mode);
+asmlinkage long sys_openat2(int dfd, const char __user *filename,
+			    const struct open_how *how);
 asmlinkage long sys_close(unsigned int fd);
 asmlinkage long sys_vhangup(void);
 
@@ -1374,15 +1377,21 @@ static inline int ksys_close(unsigned int fd)
 	return __close_fd(current->files, fd);
 }
 
-extern long do_sys_open(int dfd, const char __user *filename, int flags,
-			umode_t mode);
+extern long do_sys_open(int dfd, const char __user *filename,
+			struct open_how *how);
 
 static inline long ksys_open(const char __user *filename, int flags,
 			     umode_t mode)
 {
+	struct open_how how = {
+		.flags = flags & VALID_OPEN_FLAGS,
+		.mode = OPENHOW_MODE(flags, mode),
+	};
+
 	if (force_o_largefile())
-		flags |= O_LARGEFILE;
-	return do_sys_open(AT_FDCWD, filename, flags, mode);
+		how.flags |= O_LARGEFILE;
+
+	return do_sys_open(AT_FDCWD, filename, &how);
 }
 
 extern long do_sys_truncate(const char __user *pathname, loff_t length);
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index 1be0e798e362..b28c11b338ee 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -851,8 +851,11 @@ __SYSCALL(__NR_pidfd_open, sys_pidfd_open)
 __SYSCALL(__NR_clone3, sys_clone3)
 #endif
 
+#define __NR_openat2 437
+__SYSCALL(__NR_openat2, sys_openat2)
+
 #undef __NR_syscalls
-#define __NR_syscalls 436
+#define __NR_syscalls 438
 
 /*
  * 32 bit systems traditionally used different
diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h
index 1d338357df8a..ebfc97b3d8aa 100644
--- a/include/uapi/linux/fcntl.h
+++ b/include/uapi/linux/fcntl.h
@@ -93,5 +93,47 @@
 
 #define AT_RECURSIVE		0x8000	/* Apply to the entire subtree */
 
+/**
+ * Arguments for how openat2(2) should open the target path. If @resolve is
+ * zero, then openat2(2) operates identically to openat(2).
+ *
+ * However, unlike openat(2), unknown bits in @flags result in -EINVAL rather
+ * than being silently ignored. In addition, @mode (or @upgrade_mask) must be
+ * zero unless one of {O_CREAT, O_TMPFILE, O_PATH} are set.
+ *
+ * @flags: O_* flags.
+ * @mode: O_CREAT/O_TMPFILE file mode.
+ * @upgrade_mask: UPGRADE_* flags (to restrict O_PATH re-opening).
+ * @resolve: RESOLVE_* flags.
+ * @reserved: reserved for future extensions, must be zeroed.
+ */
+struct open_how {
+	__u32 flags;
+	union {
+		__u16 mode;
+		__u16 upgrade_mask;
+	};
+	__u16 resolve;
+	__u64 reserved[7]; /* must be zeroed */
+};
+
+/* how->resolve flags for openat2(2). */
+#define RESOLVE_NO_XDEV		0x01 /* Block mount-point crossings
+					(includes bind-mounts). */
+#define RESOLVE_NO_MAGICLINKS	0x02 /* Block traversal through procfs-style
+					"magic-links". */
+#define RESOLVE_NO_SYMLINKS	0x04 /* Block traversal through all symlinks
+					(implies OEXT_NO_MAGICLINKS) */
+#define RESOLVE_BENEATH		0x08 /* Block "lexical" trickery like
+					"..", symlinks, and absolute
+					paths which escape the dirfd. */
+#define RESOLVE_IN_ROOT		0x10 /* Make all jumps to "/" and ".."
+					be scoped inside the dirfd
+					(similar to chroot(2)). */
+
+/* how->upgrade flags for openat2(2). */
+/* First bit is reserved for a future UPGRADE_NOEXEC flag. */
+#define UPGRADE_NOREAD		0x02 /* Block re-opening with MAY_READ. */
+#define UPGRADE_NOWRITE		0x04 /* Block re-opening with MAY_WRITE. */
 
 #endif /* _UAPI_LINUX_FCNTL_H */
-- 
2.22.0


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^ permalink raw reply related

* [PATCH RESEND v11 6/8] namei: aggressively check for nd->root escape on ".." resolution
From: Aleksa Sarai @ 2019-08-20  3:34 UTC (permalink / raw)
  To: Al Viro, Jeff Layton, J. Bruce Fields, Arnd Bergmann,
	David Howells, Shuah Khan, Shuah Khan
  Cc: linux-ia64, linux-sh, Alexei Starovoitov, Oleg Nesterov,
	linux-kselftest, sparclinux, linux-arch, linux-s390,
	Tycho Andersen, Aleksa Sarai, linux-arm-kernel, linux-mips,
	linux-xtensa, Kees Cook, Jann Horn, linuxppc-dev, Aleksa Sarai,
	Andy Lutomirski, David Drysdale, Christian Brauner, linux-parisc,
	linux-m68k, linux-api, Chanho Min, linux-kernel, Eric Biederman,
	linux-alpha, linux-fsdevel, Andrew Morton, Linus Torvalds,
	containers
In-Reply-To: <20190820033406.29796-1-cyphar@cyphar.com>

This patch allows for LOOKUP_BENEATH and LOOKUP_IN_ROOT to safely permit
".." resolution (in the case of LOOKUP_BENEATH the resolution will still
fail if ".." resolution would resolve a path outside of the root --
while LOOKUP_IN_ROOT will chroot(2)-style scope it). Magic-link jumps
are still disallowed entirely because now they could result in
inconsistent behaviour if resolution encounters a subsequent ".."[*].

The need for this patch is explained by observing there is a fairly
easy-to-exploit race condition with chroot(2) (and thus by extension
LOOKUP_IN_ROOT and LOOKUP_BENEATH if ".." is allowed) where a rename(2)
of a path can be used to "skip over" nd->root and thus escape to the
filesystem above nd->root.

  thread1 [attacker]:
    for (;;)
      renameat2(AT_FDCWD, "/a/b/c", AT_FDCWD, "/a/d", RENAME_EXCHANGE);
  thread2 [victim]:
    for (;;)
      openat2(dirb, "b/c/../../etc/shadow",
              { .flags = O_PATH, .resolve = RESOLVE_IN_ROOT } );

With fairly significant regularity, thread2 will resolve to
"/etc/shadow" rather than "/a/b/etc/shadow". There is also a similar
(though somewhat more privileged) attack using MS_MOVE.

With this patch, such cases will be detected *during* ".." resolution
(which is the weak point of chroot(2) -- since walking *into* a
subdirectory tautologically cannot result in you walking *outside*
nd->root -- except through a bind-mount or magic-link). By detecting
this at ".." resolution (rather than checking only at the end of the
entire resolution) we can both correct escapes by jumping back to the
root (in the case of LOOKUP_IN_ROOT), as well as avoid revealing to
attackers the structure of the filesystem outside of the root (through
timing attacks for instance).

In order to avoid a quadratic lookup with each ".." entry, we only
activate the slow path if a write through &rename_lock or &mount_lock
has occurred during path resolution (&rename_lock and &mount_lock are
re-taken to further optimise the lookup). Since the primary attack being
protected against is MS_MOVE or rename(2), not doing additional checks
unless a mount or rename have occurred avoids making the common case
slow.

The use of path_is_under() here might seem suspect, but on further
inspection of the most important race (a path was *inside* the root but
is now *outside*), there appears to be no attack potential:

  * If path_is_under() occurs before the rename, then the path will be
    resolved -- however the path was originally inside the root and thus
    there is no escape (and to userspace it'd look like the rename
    occurred after the path was resolved). If path_is_under() occurs
    afterwards, the resolution is blocked.

  * Subsequent ".." jumps are guaranteed to check path_is_under() -- by
    construction, &rename_lock or &mount_lock must have been taken by
    the attacker after path_is_under() returned in the victim. Thus ".."
    will not be able to escape from the previously-inside-root path.

  * Walking down in the moved path is still safe since the entire
    subtree was moved (either by rename(2) or MS_MOVE) and because (as
    discussed above) walking down is safe.

A variant of the above attack is included in the selftests for
openat2(2) later in this patch series. I've run this test on several
machines for several days and no instances of a breakout were detected.
While this is not concrete proof that this is safe, when combined with
the above argument it should lend some trustworthiness to this
construction.

[*] It may be acceptable in the future to do a path_is_under() check
    after resolving a magic-link and permit resolution if the
    nd_jump_link() result is still within the dirfd. However this seems
    unlikely to be a feature that people *really* need* -- it can be
    added later if it turns out a lot of people want it.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
 fs/namei.c | 45 +++++++++++++++++++++++++++++++--------------
 1 file changed, 31 insertions(+), 14 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index 0352d275bd13..fd1eb5ce8baa 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -491,7 +491,7 @@ struct nameidata {
 	struct path	root;
 	struct inode	*inode; /* path.dentry.d_inode */
 	unsigned int	flags;
-	unsigned	seq, m_seq;
+	unsigned	seq, m_seq, r_seq;
 	int		last_type;
 	unsigned	depth;
 	int		total_link_count;
@@ -1758,22 +1758,36 @@ static inline int handle_dots(struct nameidata *nd, int type)
 	if (type == LAST_DOTDOT) {
 		int error = 0;
 
-		/*
-		 * LOOKUP_BENEATH resolving ".." is not currently safe -- races
-		 * can cause our parent to have moved outside of the root and
-		 * us to skip over it.
-		 */
-		if (unlikely(nd->flags & (LOOKUP_BENEATH | LOOKUP_IN_ROOT)))
-			return -EXDEV;
 		if (!nd->root.mnt) {
 			error = set_root(nd);
 			if (error)
 				return error;
 		}
-		if (nd->flags & LOOKUP_RCU) {
-			return follow_dotdot_rcu(nd);
-		} else
-			return follow_dotdot(nd);
+		if (nd->flags & LOOKUP_RCU)
+			error = follow_dotdot_rcu(nd);
+		else
+			error = follow_dotdot(nd);
+		if (error)
+			return error;
+
+		if (unlikely(nd->flags & (LOOKUP_BENEATH | LOOKUP_IN_ROOT))) {
+			bool m_retry = read_seqretry(&mount_lock, nd->m_seq);
+			bool r_retry = read_seqretry(&rename_lock, nd->r_seq);
+
+			/*
+			 * Don't bother checking unless there's a racing
+			 * rename(2) or MS_MOVE.
+			 */
+			if (likely(!m_retry && !r_retry))
+				return 0;
+
+			if (m_retry && !(nd->flags & LOOKUP_RCU))
+				nd->m_seq = read_seqbegin(&mount_lock);
+			if (r_retry)
+				nd->r_seq = read_seqbegin(&rename_lock);
+			if (!path_is_under(&nd->path, &nd->root))
+				return -EXDEV;
+		}
 	}
 	return 0;
 }
@@ -2245,6 +2259,11 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
 	nd->last_type = LAST_ROOT; /* if there are only slashes... */
 	nd->flags = flags | LOOKUP_JUMPED | LOOKUP_PARENT;
 	nd->depth = 0;
+
+	nd->m_seq = read_seqbegin(&mount_lock);
+	if (flags & (LOOKUP_BENEATH | LOOKUP_IN_ROOT))
+		nd->r_seq = read_seqbegin(&rename_lock);
+
 	if (flags & LOOKUP_ROOT) {
 		struct dentry *root = nd->root.dentry;
 		struct inode *inode = root->d_inode;
@@ -2266,8 +2285,6 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
 	nd->path.mnt = NULL;
 	nd->path.dentry = NULL;
 
-	nd->m_seq = read_seqbegin(&mount_lock);
-
 	/* LOOKUP_IN_ROOT treats absolute paths as being relative-to-dirfd. */
 	if (flags & LOOKUP_IN_ROOT)
 		while (*s == '/')
-- 
2.22.0


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