linux-kernel - Re: [PATCH v2 2/3] iommu/uapi: Add argsz for user filled data

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20200611170215.7005042e@jacob-builder>
Date:   Thu, 11 Jun 2020 17:02:15 -0700
From:   Jacob Pan <jacob.jun.pan@...ux.intel.com>
To:     Alex Williamson <alex.williamson@...hat.com>
Cc:     iommu@...ts.linux-foundation.org,
        LKML <linux-kernel@...r.kernel.org>,
        "Lu Baolu" <baolu.lu@...ux.intel.com>,
        Joerg Roedel <joro@...tes.org>,
        David Woodhouse <dwmw2@...radead.org>,
        Yi Liu <yi.l.liu@...el.com>,
        "Tian, Kevin" <kevin.tian@...el.com>,
        Raj Ashok <ashok.raj@...el.com>,
        "Christoph Hellwig" <hch@...radead.org>,
        Jean-Philippe Brucker <jean-philippe@...aro.com>,
        Eric Auger <eric.auger@...hat.com>,
        Jonathan Corbet <corbet@....net>, jacob.jun.pan@...ux.intel.com
Subject: Re: [PATCH v2 2/3] iommu/uapi: Add argsz for user filled data

On Thu, 11 Jun 2020 10:49:36 -0600
Alex Williamson <alex.williamson@...hat.com> wrote:

> On Wed, 10 Jun 2020 21:12:14 -0700
> Jacob Pan <jacob.jun.pan@...ux.intel.com> wrote:
> 
> > As IOMMU UAPI gets extended, user data size may increase. To support
> > backward compatibiliy, this patch introduces a size field to each
> > UAPI data structures. It is *always* the responsibility for the
> > user to fill in the correct size.  
> 
> Though at the same time, argsz is user provided data which we don't
> trust.  The argsz field allows the user to indicate how much data
> they're providing, it's still the kernel's responsibility to validate
> whether it's correct and sufficient for the requested operation.
> Thanks,
> 
Yes, will add this clarification.

Thanks,

Jacob
> Alex
> 
> > Specific scenarios for user data handling are documented in:
> > Documentation/userspace-api/iommu.rst
> > 
> > Signed-off-by: Liu Yi L <yi.l.liu@...el.com>
> > Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
> > ---
> >  include/uapi/linux/iommu.h | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
> > index e907b7091a46..303f148a5cd7 100644
> > --- a/include/uapi/linux/iommu.h
> > +++ b/include/uapi/linux/iommu.h
> > @@ -135,6 +135,7 @@ enum iommu_page_response_code {
> >  
> >  /**
> >   * struct iommu_page_response - Generic page response information
> > + * @argsz: User filled size of this data
> >   * @version: API version of this structure
> >   * @flags: encodes whether the corresponding fields are valid
> >   *         (IOMMU_FAULT_PAGE_RESPONSE_* values)
> > @@ -143,6 +144,7 @@ enum iommu_page_response_code {
> >   * @code: response code from &enum iommu_page_response_code
> >   */
> >  struct iommu_page_response {
> > +	__u32	argsz;
> >  #define IOMMU_PAGE_RESP_VERSION_1	1
> >  	__u32	version;
> >  #define IOMMU_PAGE_RESP_PASID_VALID	(1 << 0)
> > @@ -218,6 +220,7 @@ struct iommu_inv_pasid_info {
> >  /**
> >   * struct iommu_cache_invalidate_info - First level/stage
> > invalidation
> >   *     information
> > + * @argsz: User filled size of this data
> >   * @version: API version of this structure
> >   * @cache: bitfield that allows to select which caches to
> > invalidate
> >   * @granularity: defines the lowest granularity used for the
> > invalidation: @@ -246,6 +249,7 @@ struct iommu_inv_pasid_info {
> >   * must support the used granularity.
> >   */
> >  struct iommu_cache_invalidate_info {
> > +	__u32	argsz;
> >  #define IOMMU_CACHE_INVALIDATE_INFO_VERSION_1 1
> >  	__u32	version;
> >  /* IOMMU paging structure cache */
> > @@ -292,6 +296,7 @@ struct iommu_gpasid_bind_data_vtd {
> >  
> >  /**
> >   * struct iommu_gpasid_bind_data - Information about device and
> > guest PASID binding
> > + * @argsz:	User filled size of this data
> >   * @version:	Version of this data structure
> >   * @format:	PASID table entry format
> >   * @flags:	Additional information on guest bind request
> > @@ -309,6 +314,7 @@ struct iommu_gpasid_bind_data_vtd {
> >   * PASID to host PASID based on this bind data.
> >   */
> >  struct iommu_gpasid_bind_data {
> > +	__u32 argsz;
> >  #define IOMMU_GPASID_BIND_VERSION_1	1
> >  	__u32 version;
> >  #define IOMMU_PASID_FORMAT_INTEL_VTD	1  
> 

[Jacob Pan]