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From: Martijn Coenen <maco@android.com>
To: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: dmitry.torokhov@gmail.com,
	"Matt Fleming" <matt@codeblueprint.co.uk>,
	"Will Deacon" <will.deacon@arm.com>,
	platform-driver-x86@vger.kernel.org,
	"David Howells" <dhowells@redhat.com>,
	"David Brown" <david.brown@linaro.org>,
	"Peter Jones" <pjones@redhat.com>,
	"H . Peter Anvin" <hpa@zytor.com>,
	"open list:ANDROID DRIVERS" <devel@driverdev.osuosl.org>,
	nbroeking@me.com, x86@kernel.org,
	"Arve Hjønnevåg" <arve@android.com>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Andres Rodriguez" <andresx7@gmail.com>,
	"Andy Gross" <andy.gross@linaro.org>,
	"Darren Hart" <dvhart@infradead.org>,
	"Mimi Zohar" <zohar@linux.vnet.ibm.com>,
	"Arend Van Spriel" <arend.vanspriel@broadcom.com>,
	"Todd Kjos" <tkjos@android.com>,
	"Kees Cook" <keescook@chromium.org>,
	linux-efi <linux-efi@vger.kernel.org>,
	linux-arm-msm@vger.kernel.org, "Torsten Duwe" <duwe@suse.de>,
	"Josh Triplett" <josh@joshtriplett.org>,
	"Chris Wright" <chrisw@sous-sol.org>,
	"Hans de Goede" <hdegoede@redhat.com>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	bjorn.andersson@linaro.org, "Kalle Valo" <kvalo@codeaurora.org>,
	"Alan Cox" <alan@linux.intel.com>,
	mfuzzey@parkeon.com, "Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
	"Stephen Boyd" <sboyd@kernel.org>,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Vikram Mulukutla" <markivx@codeaurora.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-security-module@vger.kernel.org,
	"Dave Olsthoorn" <dave@bewaar.me>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Linus Torvalds" <torvalds@linux-foundation.org>,
	"Andy Shevchenko" <andy@infradead.org>
Subject: Re: [PATCH v3 2/5] efi: Add embedded peripheral firmware support
Date: Fri, 4 May 2018 08:26:39 -0700	[thread overview]
Message-ID: <CAB0TPYEEPq+jPfOjQmHYoXauicR=-C+APdy--1NDPUnW01i-TA@mail.gmail.com> (raw)
In-Reply-To: <20180504002142.GT27853@wotan.suse.de>

On Thu, May 3, 2018 at 5:21 PM, Luis R. Rodriguez <mcgrof@kernel.org> wrote:
> Android folks, poke below. otherwise we'll have no option but to seriously
> consider Mimi's patch to prevent these calls when IMA appraisal is enforced:

Sorry, figuring out who's the right person to answer this, will get
back to you ASAP.

Martijn

>
> http://lkml.kernel.org/r/1525182503-13849-7-git-send-email-zohar@linux.vnet.ibm.com
>
> Please read below....
>
> On Wed, Apr 25, 2018 at 05:55:57PM +0000, Luis R. Rodriguez wrote:
>> On Wed, Apr 25, 2018 at 01:00:09AM -0400, Mimi Zohar wrote:
>> > On Tue, 2018-04-24 at 23:42 +0000, Luis R. Rodriguez wrote:
>> > > On Tue, Apr 24, 2018 at 12:07:01PM -0400, Mimi Zohar wrote:
>> > > > On Tue, 2018-04-24 at 17:09 +0200, Hans de Goede wrote:
>> > > If its of any help --
>> > >
>> > > drivers/soc/qcom/mdt_loader.c is the only driver currently using
>> > > request_firmware_into_buf() however I'll note qcom_mdt_load() is used in many
>> > > other drivers so they are wrappers around request_firmware_into_buf():
>> > >
>> > > drivers/gpu/drm/msm/adreno/a5xx_gpu.c:   * adreno_request_fw() handles this, but qcom_mdt_load() does
>> > > drivers/gpu/drm/msm/adreno/a5xx_gpu.c:          ret = qcom_mdt_load(dev, fw, fwname, GPU_PAS_ID,
>> > > drivers/gpu/drm/msm/adreno/a5xx_gpu.c:          ret = qcom_mdt_load(dev, fw, newname, GPU_PAS_ID,
>> > > drivers/media/platform/qcom/venus/firmware.c:   ret = qcom_mdt_load(dev, mdt, fwname, VENUS_PAS_ID, mem_va, mem_phys,
>> > > drivers/remoteproc/qcom_adsp_pil.c:     return qcom_mdt_load(adsp->dev, fw, rproc->firmware, adsp->pas_id,
>> > > drivers/remoteproc/qcom_wcnss.c:        return qcom_mdt_load(wcnss->dev, fw, rproc->firmware, WCNSS_PAS_ID,
>> > >
>> > > > > As such the current IMA code (from v4.17-rc2) actually does
>> > > > > not handle READING_FIRMWARE_PREALLOC_BUFFER at all,
>> > > >
>> > > > Right, it doesn't yet address READING_FIRMWARE_PREALLOC_BUFFER, but
>> > > > should.
>> > > >
>> > > > Depending on whether the device requesting the firmware has access to
>> > > > the DMA memory, before the signature verification,
>> > >
>> > > It would seem from the original patch review about READING_FIRMWARE_PREALLOC_BUFFER
>> > > that this is not a DMA buffer.
>
> To be very clear I believe Stephen implied this was not DMA buffer. Mimi
> asked for READING_FIRMWARE_DMA if it was:
>
> https://patchwork.kernel.org/patch/9074611/
>
>> > The call sequence:
>> > qcom_mdt_load() -> qcom_scm_pas_init_image() -> dma_alloc_coherent()
>> >
>> > If dma_alloc_coherent() isn't allocating a DMA buffer, then the
>> > function name is misleading/confusing.
>>
>> Hah, by *definition* the device *and* processor has immediate access
>> to data written *immediately* when dma_alloc_coherent() is used. From
>> Documentation/DMA-API.txt:
>>
>> -----------------------------------------------------------------------
>> Part Ia - Using large DMA-coherent buffers
>> ------------------------------------------
>>
>> ::
>>
>>         void *
>>         dma_alloc_coherent(struct device *dev, size_t size,
>>                            dma_addr_t *dma_handle, gfp_t flag)
>>
>> Consistent memory is memory for which a write by either the device or
>> the processor can immediately be read by the processor or device
>> without having to worry about caching effects.  (You may however need
>> to make sure to flush the processor's write buffers before telling
>> devices to read that memory.)
>> ------------------------------------------------------------------------
>>
>> Is ptr below
>>
>>       ret = request_firmware_into_buf(&seg_fw, fw_name, dev,
>>                                       ptr, phdr->p_filesz);
>>
>> Also part of the DMA buffer allocated earlier via:
>>
>>         ret = qcom_scm_pas_init_image(pas_id, fw->data, fw->size);
>>
>> Android folks?
>
> Android folks?
>
>> > > The device driver should have access to the buffer pointer with write given
>> > > that with request_firmware_into_buf() the driver is giving full write access to
>> > > the memory pointer so that the firmware API can stuff the firmware it finds
>> > > there.
>> > >
>> > > Firmware signature verification would be up to the device hardware to do upon
>> > > load *after* request_firmware_into_buf().
>> >
>> > We're discussing the kernel's signature verification, not the device
>> > hardware's signature verification.  Can the device driver access the
>> > buffer, before IMA-appraisal has verified the firmware's signature?
>>
>> It will depend on the above question.
>
>   Luis
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  reply	other threads:[~2018-05-04 15:26 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-08 17:40 [PATCH v3 0/5] efi/firmware/platform-x86: Add EFI embedded fw support Hans de Goede
2018-04-08 17:40 ` [PATCH v3 1/5] efi: Export boot-services code and data as debugfs-blobs Hans de Goede
2018-04-16  8:23   ` Ard Biesheuvel
2018-04-24 13:11     ` Hans de Goede
2018-04-23 11:55   ` Greg Kroah-Hartman
2018-04-08 17:40 ` [PATCH v3 2/5] efi: Add embedded peripheral firmware support Hans de Goede
2018-04-16  8:28   ` Ard Biesheuvel
2018-04-24 13:17     ` Hans de Goede
2018-04-17  0:17   ` Luis R. Rodriguez
2018-04-17  8:58     ` Hans de Goede
2018-04-17  9:19     ` Hans de Goede
2018-04-23 21:11   ` Luis R. Rodriguez
2018-04-24 15:09     ` Hans de Goede
2018-04-24 16:07       ` Mimi Zohar
2018-04-24 18:33         ` Hans de Goede
2018-04-24 23:42         ` Luis R. Rodriguez
2018-04-25  5:00           ` Mimi Zohar
2018-04-25 17:55             ` Luis R. Rodriguez
2018-05-04  0:21               ` Luis R. Rodriguez
2018-05-04 15:26                 ` Martijn Coenen [this message]
2018-05-04 19:44               ` Martijn Coenen
2018-05-08 15:38                 ` Luis R. Rodriguez
2018-05-08 16:10                   ` Luis R. Rodriguez
2018-06-07 16:49                     ` Bjorn Andersson
2018-06-07 18:22                       ` Luis R. Rodriguez
2018-06-01 19:23                   ` Luis R. Rodriguez
2018-06-06 20:32                     ` Do Qualcomm drivers use DMA buffers for request_firmware_into_buf()? Luis R. Rodriguez
2018-06-07 16:18                       ` Bjorn Andersson
     [not found]                         ` <CAKv+Gu8+Fq7BD4XD-YCyXzZh0mg6Z2k-0styj0cw6_uZfaqy4Q@mail.gmail.com>
     [not found]                           ` <20180607163308.GA18834@kroah.com>
2018-06-08  6:41                             ` Vlastimil Babka
2018-06-07 16:33             ` [PATCH v3 2/5] efi: Add embedded peripheral firmware support Bjorn Andersson
2018-04-08 17:40 ` [PATCH v3 3/5] platform/x86: Rename silead_dmi to touchscreen_dmi Hans de Goede
2018-04-09  8:07   ` Andy Shevchenko
2018-04-20  0:20     ` Darren Hart
2018-04-08 17:40 ` [PATCH v3 4/5] platform/x86: touchscreen_dmi: Add EFI embedded firmware info support Hans de Goede
2018-04-08 17:40 ` [PATCH v3 5/5] platform/x86: touchscreen_dmi: Add info for the Chuwi Vi8 Plus tablet Hans de Goede
2018-04-09  8:10   ` Andy Shevchenko

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