lkml.org 
[lkml]   [2018]   [Dec]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v3 6/9] iommu/dma-iommu.c: Convert to use vm_insert_range
From
Date
On 07/12/2018 20:41, Souptick Joarder wrote:
> On Fri, Dec 7, 2018 at 7:17 PM Robin Murphy <robin.murphy@arm.com> wrote:
>>
>> On 06/12/2018 18:43, Souptick Joarder wrote:
>>> Convert to use vm_insert_range() to map range of kernel
>>> memory to user vma.
>>>
>>> Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
>>> Reviewed-by: Matthew Wilcox <willy@infradead.org>
>>> ---
>>> drivers/iommu/dma-iommu.c | 13 +++----------
>>> 1 file changed, 3 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>>> index d1b0475..a2c65e2 100644
>>> --- a/drivers/iommu/dma-iommu.c
>>> +++ b/drivers/iommu/dma-iommu.c
>>> @@ -622,17 +622,10 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
>>>
>>> int iommu_dma_mmap(struct page **pages, size_t size, struct vm_area_struct *vma)
>>> {
>>> - unsigned long uaddr = vma->vm_start;
>>> - unsigned int i, count = PAGE_ALIGN(size) >> PAGE_SHIFT;
>>> - int ret = -ENXIO;
>>> + unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
>>>
>>> - for (i = vma->vm_pgoff; i < count && uaddr < vma->vm_end; i++) {
>>> - ret = vm_insert_page(vma, uaddr, pages[i]);
>>> - if (ret)
>>> - break;
>>> - uaddr += PAGE_SIZE;
>>> - }
>>> - return ret;
>>> + return vm_insert_range(vma, vma->vm_start,
>>> + pages + vma->vm_pgoff, count);
>>
>> You also need to adjust count to compensate for the pages skipped by
>> vm_pgoff, otherwise you've got an out-of-bounds dereference triggered
>> from userspace, which is pretty high up the "not good" scale (not to
>> mention the entire call would then propagate -EFAULT back from
>> vm_insert_page() and thus always appear to fail for nonzero offsets).
>
> So this should something similar to ->
>
> return vm_insert_range(vma, vma->vm_start,
> pages + vma->vm_pgoff, count - vma->vm_pgoff);
>

Yup, I think that looks appropriate.

Robin.

\
 
 \ /
  Last update: 2018-12-10 17:32    [W:0.045 / U:32.060 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site