From: David Stevens stevensd@chromium.org
commit 2cbc61a1b1665c84282dbf2b1747ffa0b6248639 upstream.
Pass the non-aligned size to __iommu_dma_map when using swiotlb bounce buffers in iommu_dma_map_page, to account for min_align_mask.
To deal with granule alignment, __iommu_dma_map maps iova_align(size + iova_off) bytes starting at phys - iova_off. If iommu_dma_map_page passes aligned size when using swiotlb, then this becomes iova_align(iova_align(orig_size) + iova_off). Normally iova_off will be zero when using swiotlb. However, this is not the case for devices that set min_align_mask. When iova_off is non-zero, __iommu_dma_map ends up mapping an extra page at the end of the buffer. Beyond just being a security issue, the extra page is not cleaned up by __iommu_dma_unmap. This causes problems when the IOVA is reused, due to collisions in the iommu driver. Just passing the original size is sufficient, since __iommu_dma_map will take care of granule alignment.
Fixes: 1f221a0d0dbf ("swiotlb: respect min_align_mask") Signed-off-by: David Stevens stevensd@chromium.org Link: https://lore.kernel.org/r/20210929023300.335969-8-stevensd@google.com Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iommu/dma-iommu.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
--- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -806,7 +806,6 @@ static dma_addr_t iommu_dma_map_page(str struct iommu_domain *domain = iommu_get_dma_domain(dev); struct iommu_dma_cookie *cookie = domain->iova_cookie; struct iova_domain *iovad = &cookie->iovad; - size_t aligned_size = size; dma_addr_t iova, dma_mask = dma_get_mask(dev);
/* @@ -815,7 +814,7 @@ static dma_addr_t iommu_dma_map_page(str */ if (dev_use_swiotlb(dev) && iova_offset(iovad, phys | size)) { void *padding_start; - size_t padding_size; + size_t padding_size, aligned_size;
aligned_size = iova_align(iovad, size); phys = swiotlb_tbl_map_single(dev, phys, size, aligned_size, @@ -840,7 +839,7 @@ static dma_addr_t iommu_dma_map_page(str if (!coherent && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) arch_sync_dma_for_device(phys, size, dir);
- iova = __iommu_dma_map(dev, phys, aligned_size, prot, dma_mask); + iova = __iommu_dma_map(dev, phys, size, prot, dma_mask); if (iova == DMA_MAPPING_ERROR && is_swiotlb_buffer(dev, phys)) swiotlb_tbl_unmap_single(dev, phys, size, dir, attrs); return iova;