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Commit 50262a4b authored by Marek Szyprowski's avatar Marek Szyprowski
Browse files

ARM: dma-mapping: add more sanity checks in arm_dma_mmap() 



Add some sanity checks and forbid mmaping of buffers into vma areas larger
than allocated dma buffer.

Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
parent e9da6e99

arch/arm/mm/dma-mapping.c

+10 −4
Original line number Diff line number Diff line
@@ -611,16 +611,22 @@ int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma, 
{

	int ret = -ENXIO;

#ifdef CONFIG_MMU

	unsigned long nr_vma_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;

	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;

	unsigned long pfn = dma_to_pfn(dev, dma_addr);

	unsigned long off = vma->vm_pgoff;



	vma->vm_page_prot = __get_dma_pgprot(attrs, vma->vm_page_prot);



	if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret))

		return ret;



	if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) {

		ret = remap_pfn_range(vma, vma->vm_start,

			      pfn + vma->vm_pgoff,

				      pfn + off,

				      vma->vm_end - vma->vm_start,

				      vma->vm_page_prot);

	}

#endif	/* CONFIG_MMU */



	return ret;