Re: [PATCH] iommufd/selftest: Fix buffer read overrrun in the dirty test

[Jason Gunthorpe <jgg@ziepe.ca>]

On Thu, Aug 22, 2024 at 11:47:09AM -0300, Jason Gunthorpe wrote:
> test_bit() is used to read the memory storing the bitmap, however
> test_bit() always uses a unsigned long 8 byte access.
> 
> If the bitmap is not an aligned size of 64 bits this will now trigger a
> KASAN warning reading past the end of the buffer.
> 
> Properly round the buffer allocation to an unsigned long size. Continue to
> copy_from_user() using a byte granularity.
> 
> Fixes: 9560393b830b ("iommufd/selftest: Fix iommufd_test_dirty() to handle <u8 bitmaps")
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/iommu/iommufd/selftest.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)

Applied to for-next

Jason