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Commit d81e870d authored by Marek Szyprowski's avatar Marek Szyprowski Committed by Mauro Carvalho Chehab
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[media] v4l: vb2-dma-contig: fail if user ptr buffer is not correctly aligned 



The DMA transfer must be aligned to a specific value. If userptr is not aligned
to DMA requirements then unexpected corruptions of the memory may occur before
or after a buffer.  To prevent such situations, all unligned userptr buffers
are rejected at VIDIOC_QBUF.

Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 67a5d0ce

drivers/media/v4l2-core/videobuf2-dma-contig.c

+12 −0
Original line number Diff line number Diff line
@@ -491,6 +491,18 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr, 
	struct vm_area_struct *vma;

	struct sg_table *sgt;

	unsigned long contig_size;

	unsigned long dma_align = dma_get_cache_alignment();



	/* Only cache aligned DMA transfers are reliable */

	if (!IS_ALIGNED(vaddr | size, dma_align)) {

		pr_debug("user data must be aligned to %lu bytes\n", dma_align);

		return ERR_PTR(-EINVAL);

	}



	if (!size) {

		pr_debug("size is zero\n");

		return ERR_PTR(-EINVAL);

	}



	buf = kzalloc(sizeof *buf, GFP_KERNEL);

	if (!buf)