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| author | Jason Gunthorpe <jgg@nvidia.com> | 2025-10-08 15:17:18 -0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-11-13 15:34:39 -0500 |
| commit | de7f2c67ceb1941b05b04ac35458a03e93cc57b1 (patch) | |
| tree | 2736322ee34ce41bf3578079d9ed5c1b466e67e1 | |
| parent | 4b7d4aa5399b5a64caee639275615c63c008540d (diff) | |
| download | linux-de7f2c67ceb1941b05b04ac35458a03e93cc57b1.tar.gz linux-de7f2c67ceb1941b05b04ac35458a03e93cc57b1.tar.bz2 linux-de7f2c67ceb1941b05b04ac35458a03e93cc57b1.zip | |
iommufd: Don't overflow during division for dirty tracking
commit cb30dfa75d55eced379a42fd67bd5fb7ec38555e upstream.
If pgshift is 63 then BITS_PER_TYPE(*bitmap->bitmap) * pgsize will overflow
to 0 and this triggers divide by 0.
In this case the index should just be 0, so reorganize things to divide
by shift and avoid hitting any overflows.
Link: https://patch.msgid.link/r/0-v1-663679b57226+172-iommufd_dirty_div0_jgg@nvidia.com
Cc: stable@vger.kernel.org
Fixes: 58ccf0190d19 ("vfio: Add an IOVA bitmap support")
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reported-by: syzbot+093a8a8b859472e6c257@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=093a8a8b859472e6c257
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/iommu/iommufd/iova_bitmap.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/iommu/iommufd/iova_bitmap.c b/drivers/iommu/iommufd/iova_bitmap.c index 2cdc4f542df4..0943a351fb91 100644 --- a/drivers/iommu/iommufd/iova_bitmap.c +++ b/drivers/iommu/iommufd/iova_bitmap.c @@ -130,9 +130,8 @@ struct iova_bitmap { static unsigned long iova_bitmap_offset_to_index(struct iova_bitmap *bitmap, unsigned long iova) { - unsigned long pgsize = 1UL << bitmap->mapped.pgshift; - - return iova / (BITS_PER_TYPE(*bitmap->bitmap) * pgsize); + return (iova >> bitmap->mapped.pgshift) / + BITS_PER_TYPE(*bitmap->bitmap); } /* |