From: Jason Gunthorpe <jgg@ziepe.ca>
To: "Christian König" <ckoenig.leichtzumerken@gmail.com>
Cc: akpm@linux-foundation.org, sumit.semwal@linaro.org,
linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, Daniel Vetter <daniel.vetter@ffwll.ch>
Subject: Re: Changing vma->vm_file in dma_buf_mmap()
Date: Mon, 14 Sep 2020 11:06:32 -0300 [thread overview]
Message-ID: <20200914140632.GD1221970@ziepe.ca> (raw)
In-Reply-To: <40cd26ae-b855-4627-5a13-4dcea5d622f6@gmail.com>
On Mon, Sep 14, 2020 at 03:30:47PM +0200, Christian König wrote:
> Am 14.09.20 um 15:29 schrieb Christian König:
> > Hi Andrew,
> >
> > I'm the new DMA-buf maintainer and Daniel and others came up with
> > patches extending the use of the dma_buf_mmap() function.
> >
> > Now this function is doing something a bit odd by changing the
> > vma->vm_file while installing a VMA in the mmap() system call
It doesn't look obviously safe as mmap_region() has an interesting mix
of file and vma->file
Eg it calls mapping_unmap_writable() using both routes
What about security? Is it OK that some other random file, maybe in
another process, is being linked to this mmap?
> > The background here is that DMA-buf allows device drivers to
> > export buffer which are then imported into another device
> > driver. The mmap() handler of the importing device driver then
> > find that the pgoff belongs to the exporting device and so
> > redirects the mmap() call there.
So the pgoff is some virtualized thing?
Jason
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@ziepe.ca>
To: "Christian König" <ckoenig.leichtzumerken@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org,
akpm@linux-foundation.org, linux-media@vger.kernel.org
Subject: Re: Changing vma->vm_file in dma_buf_mmap()
Date: Mon, 14 Sep 2020 11:06:32 -0300 [thread overview]
Message-ID: <20200914140632.GD1221970@ziepe.ca> (raw)
In-Reply-To: <40cd26ae-b855-4627-5a13-4dcea5d622f6@gmail.com>
On Mon, Sep 14, 2020 at 03:30:47PM +0200, Christian König wrote:
> Am 14.09.20 um 15:29 schrieb Christian König:
> > Hi Andrew,
> >
> > I'm the new DMA-buf maintainer and Daniel and others came up with
> > patches extending the use of the dma_buf_mmap() function.
> >
> > Now this function is doing something a bit odd by changing the
> > vma->vm_file while installing a VMA in the mmap() system call
It doesn't look obviously safe as mmap_region() has an interesting mix
of file and vma->file
Eg it calls mapping_unmap_writable() using both routes
What about security? Is it OK that some other random file, maybe in
another process, is being linked to this mmap?
> > The background here is that DMA-buf allows device drivers to
> > export buffer which are then imported into another device
> > driver. The mmap() handler of the importing device driver then
> > find that the pgoff belongs to the exporting device and so
> > redirects the mmap() call there.
So the pgoff is some virtualized thing?
Jason
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next prev parent reply other threads:[~2020-09-14 14:07 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-14 13:29 Changing vma->vm_file in dma_buf_mmap() Christian König
2020-09-14 13:29 ` Christian König
2020-09-14 13:29 ` [PATCH 1/2] drm/shmem-helpers: revert "Redirect mmap for imported dma-buf" Christian König
2020-09-14 13:29 ` Christian König
2020-09-15 10:39 ` Daniel Vetter
2020-09-15 10:39 ` Daniel Vetter
2020-09-15 10:39 ` Daniel Vetter
2020-09-15 11:03 ` Christian König
2020-09-15 11:03 ` Christian König
2020-09-15 11:03 ` Christian König
2020-09-15 11:07 ` Daniel Vetter
2020-09-15 11:07 ` Daniel Vetter
2020-09-15 11:07 ` Daniel Vetter
2020-09-14 13:29 ` [PATCH 2/2] mm: introduce vma_set_file function Christian König
2020-09-14 13:29 ` Christian König
2020-09-15 9:19 ` kernel test robot
2020-09-15 9:19 ` kernel test robot
2020-09-15 9:19 ` kernel test robot
2020-09-15 11:57 ` kernel test robot
2020-09-15 11:57 ` kernel test robot
2020-09-15 11:57 ` kernel test robot
2020-09-14 13:30 ` Changing vma->vm_file in dma_buf_mmap() Christian König
2020-09-14 13:30 ` Christian König
2020-09-14 14:06 ` Jason Gunthorpe [this message]
2020-09-14 14:06 ` Jason Gunthorpe
2020-09-14 18:26 ` Christian König
2020-09-14 18:26 ` Christian König
2020-09-16 9:53 ` Daniel Vetter
2020-09-16 9:53 ` Daniel Vetter
2020-09-16 10:14 ` Christian König
2020-09-16 10:14 ` Christian König
2020-09-16 11:45 ` Christian König
2020-09-16 11:45 ` Christian König
2020-09-16 12:41 ` Daniel Vetter
2020-09-16 12:41 ` Daniel Vetter
2020-09-16 12:41 ` Daniel Vetter
2020-09-16 14:07 ` Jason Gunthorpe
2020-09-16 14:07 ` Jason Gunthorpe
2020-09-16 14:14 ` Christian König
2020-09-16 14:14 ` Christian König
2020-09-16 15:24 ` Daniel Vetter
2020-09-16 15:24 ` Daniel Vetter
2020-09-16 15:24 ` Daniel Vetter
2020-09-16 15:31 ` [Linaro-mm-sig] " Christian König
2020-09-16 15:31 ` Christian König
2020-09-16 15:31 ` Christian König
2020-09-17 6:23 ` Daniel Vetter
2020-09-17 6:23 ` Daniel Vetter
2020-09-17 6:23 ` Daniel Vetter
2020-09-17 7:11 ` Christian König
2020-09-17 7:11 ` Christian König
2020-09-17 7:11 ` Christian König
2020-09-17 8:09 ` Daniel Vetter
2020-09-17 8:09 ` Daniel Vetter
2020-09-17 8:09 ` Daniel Vetter
2020-09-17 11:31 ` Jason Gunthorpe
2020-09-17 11:31 ` Jason Gunthorpe
2020-09-17 12:03 ` Christian König
2020-09-17 12:03 ` Christian König
2020-09-17 12:18 ` Jason Gunthorpe
2020-09-17 12:18 ` Jason Gunthorpe
2020-09-17 12:18 ` Jason Gunthorpe
2020-09-17 12:24 ` Christian König
2020-09-17 12:24 ` Christian König
2020-09-17 12:24 ` Christian König
2020-09-17 12:26 ` Daniel Vetter
2020-09-17 12:26 ` Daniel Vetter
2020-09-17 12:26 ` Daniel Vetter
2020-09-17 14:35 ` Jason Gunthorpe
2020-09-17 14:35 ` Jason Gunthorpe
2020-09-17 14:35 ` Jason Gunthorpe
2020-09-17 14:54 ` Christian König
2020-09-17 14:54 ` Christian König
2020-09-17 14:54 ` Christian König
2020-09-17 15:24 ` Jason Gunthorpe
2020-09-17 15:24 ` Jason Gunthorpe
2020-09-17 15:24 ` Jason Gunthorpe
2020-09-17 15:37 ` Daniel Vetter
2020-09-17 15:37 ` Daniel Vetter
2020-09-17 16:06 ` Christian König
2020-09-17 16:06 ` Christian König
2020-09-17 16:06 ` Christian König
2020-09-17 16:39 ` Jason Gunthorpe
2020-09-17 16:39 ` Jason Gunthorpe
2020-09-17 16:39 ` Jason Gunthorpe
2020-09-17 17:23 ` Daniel Vetter
2020-09-17 17:23 ` Daniel Vetter
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