On 07/12/2018 20:41, Souptick Joarder wrote:
On Fri, Dec 7, 2018 at 7:17 PM Robin Murphy <robin.murphy@xxxxxxx> 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@xxxxxxxxx>
Reviewed-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
---
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.
