From: Joao Martins Date: Fri, 2 Feb 2024 13:34:07 +0000 (+0000) Subject: iommufd/iova_bitmap: Bounds check mapped::pages access X-Git-Tag: v6.8-rc6~28^2~10 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a4ab7dedaee0e39b15653c5fd0367e420739f7ef;p=thirdparty%2Fkernel%2Flinux.git iommufd/iova_bitmap: Bounds check mapped::pages access Dirty IOMMU hugepages reported on a base page page-size granularity can lead to an attempt to set dirty pages in the bitmap beyond the limits that are pinned. Bounds check the page index of the array we are trying to access is within the limits before we kmap() and return otherwise. While it is also a defensive check, this is also in preparation to defer setting bits (outside the mapped range) to the next iteration(s) when the pages become available. Fixes: b058ea3ab5af ("vfio/iova_bitmap: refactor iova_bitmap_set() to better handle page boundaries") Link: https://lore.kernel.org/r/20240202133415.23819-2-joao.m.martins@oracle.com Signed-off-by: Joao Martins Tested-by: Avihai Horon Signed-off-by: Jason Gunthorpe --- diff --git a/drivers/iommu/iommufd/iova_bitmap.c b/drivers/iommu/iommufd/iova_bitmap.c index 0a92c9eeaf7f5..a3606b4c22292 100644 --- a/drivers/iommu/iommufd/iova_bitmap.c +++ b/drivers/iommu/iommufd/iova_bitmap.c @@ -409,6 +409,7 @@ void iova_bitmap_set(struct iova_bitmap *bitmap, mapped->pgshift) + mapped->pgoff * BITS_PER_BYTE; unsigned long last_bit = (((iova + length - 1) - mapped->iova) >> mapped->pgshift) + mapped->pgoff * BITS_PER_BYTE; + unsigned long last_page_idx = mapped->npages - 1; do { unsigned int page_idx = cur_bit / BITS_PER_PAGE; @@ -417,6 +418,9 @@ void iova_bitmap_set(struct iova_bitmap *bitmap, last_bit - cur_bit + 1); void *kaddr; + if (unlikely(page_idx > last_page_idx)) + break; + kaddr = kmap_local_page(mapped->pages[page_idx]); bitmap_set(kaddr, offset, nbits); kunmap_local(kaddr);