Messages in this thread | | | Subject | Re: [PATCH v3 6/9] iommu/dma-iommu.c: Convert to use vm_insert_range | From | Robin Murphy <> | Date | Fri, 7 Dec 2018 13:47:19 +0000 |
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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, >
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