Re: [PATCH v2] drivers: dma-mapping: Do not leave an invalid area->pages pointer in dma_common_contiguous_remap()

From: Greg Kroah-Hartman
Date: Wed May 03 2017 - 11:19:25 EST

On Wed, May 03, 2017 at 03:57:48PM +0100, Catalin Marinas wrote:
> The dma_common_pages_remap() function allocates a vm_struct object and
> initialises the pages pointer to value passed as argument. However, when
> this function is called dma_common_contiguous_remap(), the pages array
> is only temporarily allocated, being freed shortly after
> dma_common_contiguous_remap() returns. Architecture code checking the
> validity of an area->pages pointer would incorrectly dereference already
> freed pointers. This has been exposed by the arm64 commit 44176bb38fa4
> ("arm64: Add support for DMA_ATTR_FORCE_CONTIGUOUS to IOMMU").
> Fixes: 513510ddba96 ("common: dma-mapping: introduce common remapping functions")
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Reported-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
> Acked-by: Laura Abbott <labbott@xxxxxxxxxx>
> Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
> Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> ---
> Greg,
> Please merge this patch via your tree (and therefore I haven't added
> your ack). Thanks.

Ok, will queue it up after 4.12-rc1 is out.


greg k-h