Messages in this thread | | | Date | Thu, 13 Oct 2022 08:37:30 -0700 | From | Jerry Snitselaar <> | Subject | Re: [RFC PATCH] iommu/vt-d: Add sanity check to iommu_sva_bind_device() |
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On Thu, Oct 13, 2022 at 08:33:55AM -0700, Jerry Snitselaar wrote: > iommu_sva_bind_device() should only be called if > iommu_dev_enable_feature() succeeded. There has been one case already > where that hasn't been the case, which resulted in a null pointer > deref in dev_iommu_ops(). To avoid that happening in the future if > another driver makes that mistake, sanity check dev->iommu and > dev->iommu->iommu_dev prior to calling dev_iommu_ops(). > > Cc: Joerg Roedel <joro@8bytes.org> > Cc: Will Deacon <will@kernel.org> > Cc: Robin Murphy <robin.murphy@arm.com> > Cc: Lu Baolu <baolu.lu@linux.intel.com> > Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com> > ---
I don't know how many other drivers there will be in the future, so quite possibly a non-issue. It did happen with the idxd driver though, and I was thinking about that this morning so thought I would send a patch to avoid it in the future.
Regards, Jerry
> drivers/iommu/iommu.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 4893c2429ca5..20ec75667529 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -2746,7 +2746,15 @@ iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata) > { > struct iommu_group *group; > struct iommu_sva *handle = ERR_PTR(-EINVAL); > - const struct iommu_ops *ops = dev_iommu_ops(dev); > + const struct iommu_ops *ops; > + > + if (!dev->iommu || !dev->iommu->iommu_dev) { > + dev_warn(dev, "%s called without checking succes of iommu_dev_enable_feature?\n", > + __func__); > + return ERR_PTR(-ENODEV); > + } > + > + ops = dev_iommu_ops(dev); > > if (!ops->sva_bind) > return ERR_PTR(-ENODEV); > -- > 2.37.2 >
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