* [PATCH v3 6/9] iommu/dma-iommu.c: Convert to use vm_insert_range
@ 2018-12-06 18:43 Souptick Joarder
2018-12-07 13:47 ` Robin Murphy
0 siblings, 1 reply; 4+ messages in thread
From: Souptick Joarder @ 2018-12-06 18:43 UTC (permalink / raw)
To: akpm, willy, mhocko, joro; +Cc: iommu, linux-kernel, linux-mm
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);
}
static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v3 6/9] iommu/dma-iommu.c: Convert to use vm_insert_range
2018-12-06 18:43 [PATCH v3 6/9] iommu/dma-iommu.c: Convert to use vm_insert_range Souptick Joarder
@ 2018-12-07 13:47 ` Robin Murphy
2018-12-07 20:41 ` Souptick Joarder
0 siblings, 1 reply; 4+ messages in thread
From: Robin Murphy @ 2018-12-07 13:47 UTC (permalink / raw)
To: Souptick Joarder, akpm, willy, mhocko, joro; +Cc: linux-mm, iommu, linux-kernel
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).
Robin.
> }
>
> static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v3 6/9] iommu/dma-iommu.c: Convert to use vm_insert_range
2018-12-07 13:47 ` Robin Murphy
@ 2018-12-07 20:41 ` Souptick Joarder
2018-12-10 16:31 ` Robin Murphy
0 siblings, 1 reply; 4+ messages in thread
From: Souptick Joarder @ 2018-12-07 20:41 UTC (permalink / raw)
To: robin.murphy
Cc: Andrew Morton, Matthew Wilcox, Michal Hocko, joro, Linux-MM,
iommu, linux-kernel
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);
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v3 6/9] iommu/dma-iommu.c: Convert to use vm_insert_range
2018-12-07 20:41 ` Souptick Joarder
@ 2018-12-10 16:31 ` Robin Murphy
0 siblings, 0 replies; 4+ messages in thread
From: Robin Murphy @ 2018-12-10 16:31 UTC (permalink / raw)
To: Souptick Joarder
Cc: Andrew Morton, Matthew Wilcox, Michal Hocko, joro, Linux-MM,
iommu, linux-kernel
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.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-12-06 18:43 [PATCH v3 6/9] iommu/dma-iommu.c: Convert to use vm_insert_range Souptick Joarder
2018-12-07 13:47 ` Robin Murphy
2018-12-07 20:41 ` Souptick Joarder
2018-12-10 16:31 ` Robin Murphy
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