This is a note to let you know that I've just added the patch titled
iommufd/iova_bitmap: Bounds check mapped::pages access
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iommufd-iova_bitmap-bounds-check-mapped-pages-access.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7bba0b52763dad2f32cf509dc2182a28561504d3
Author: Joao Martins <joao.m.martins@xxxxxxxxxx>
Date: Fri Feb 2 13:34:07 2024 +0000
iommufd/iova_bitmap: Bounds check mapped::pages access
[ Upstream commit a4ab7dedaee0e39b15653c5fd0367e420739f7ef ]
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@xxxxxxxxxx
Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
Tested-by: Avihai Horon <avihaih@xxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/vfio/iova_bitmap.c b/drivers/vfio/iova_bitmap.c
index 0f19d502f351b..5b540a164c98f 100644
--- a/drivers/vfio/iova_bitmap.c
+++ b/drivers/vfio/iova_bitmap.c
@@ -405,6 +405,7 @@ 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;
@@ -413,6 +414,9 @@ 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);
