Messages in this thread | | | Subject | Re: [PATCH v3 4/5] iommu/uapi: Handle data and argsz filled by users | From | Lu Baolu <> | Date | Wed, 24 Jun 2020 14:54:49 +0800 |
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Hi Jacob,
On 2020/6/24 1:03, Jacob Pan wrote: > IOMMU UAPI data has a user filled argsz field which indicates the data > length comes with the API call. User data is not trusted, argsz must be > validated based on the current kernel data size, mandatory data size, > and feature flags. > > User data may also be extended, results in possible argsz increase. > Backward compatibility is ensured based on size and flags checking. > Details are documented in Documentation/userspace-api/iommu.rst > > This patch adds sanity checks in both IOMMU layer and vendor code, where > VT-d is the only user for now. > > Signed-off-by: Liu Yi L <yi.l.liu@intel.com> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> > --- > drivers/iommu/intel/svm.c | 3 ++ > drivers/iommu/iommu.c | 96 ++++++++++++++++++++++++++++++++++++++++++++--- > include/linux/iommu.h | 7 ++-- > 3 files changed, 98 insertions(+), 8 deletions(-) > > diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c > index 713b3a218483..237db56878c0 100644 > --- a/drivers/iommu/intel/svm.c > +++ b/drivers/iommu/intel/svm.c > @@ -244,6 +244,9 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev, > data->format != IOMMU_PASID_FORMAT_INTEL_VTD) > return -EINVAL; > > + if (data->argsz != offsetofend(struct iommu_gpasid_bind_data, vendor.vtd)) > + return -EINVAL;
Need to do size check in intel_iommu_sva_invalidate() as well?
> + > if (!dev_is_pci(dev)) > return -ENOTSUPP; > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index d43120eb1dc5..4a025c429b41 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -1951,22 +1951,108 @@ int iommu_attach_device(struct iommu_domain *domain, struct device *dev) > EXPORT_SYMBOL_GPL(iommu_attach_device); > > int iommu_cache_invalidate(struct iommu_domain *domain, struct device *dev, > - struct iommu_cache_invalidate_info *inv_info) > + void __user *uinfo)
Nit: keep it aligned.
> { > + struct iommu_cache_invalidate_info inv_info; > + unsigned long minsz, maxsz; > + > if (unlikely(!domain->ops->cache_invalidate)) > return -ENODEV; > > - return domain->ops->cache_invalidate(domain, dev, inv_info); > + /* Current kernel data size is the max to be copied from user */ > + maxsz = sizeof(struct iommu_cache_invalidate_info); > + memset((void *)&inv_info, 0, maxsz); > + > + /* > + * No new spaces can be added before the variable sized union, the > + * minimum size is the offset to the union. > + */ > + minsz = offsetof(struct iommu_cache_invalidate_info, granu); > + > + /* Copy minsz from user to get flags and argsz */ > + if (copy_from_user(&inv_info, uinfo, minsz)) > + return -EFAULT; > + > + /* Fields before variable size union is mandatory */ > + if (inv_info.argsz < minsz) > + return -EINVAL; > + /* > + * User might be using a newer UAPI header, we shall let IOMMU vendor > + * driver decide on what size it needs. Since the UAPI data extension > + * can be vendor specific, larger argsz could be the result of extension > + * for one vendor but it should not affect another vendor. > + */ > + /* > + * User might be using a newer UAPI header which has a larger data > + * size, we shall support the existing flags within the current > + * size. > + */ > + if (inv_info.argsz > maxsz) > + inv_info.argsz = maxsz; > + > + /* Checking the exact argsz based on generic flags */ > + if (inv_info.granularity == IOMMU_INV_GRANU_ADDR && > + inv_info.argsz != offsetofend(struct iommu_cache_invalidate_info, > + granu.addr_info)) > + return -EINVAL; > + > + if (inv_info.granularity == IOMMU_INV_GRANU_PASID && > + inv_info.argsz != offsetofend(struct iommu_cache_invalidate_info, > + granu.pasid_info)) > + return -EINVAL; > + > + /* Copy the remaining user data _after_ minsz */ > + if (copy_from_user((void *)&inv_info + minsz, uinfo + minsz, > + inv_info.argsz - minsz)) > + return -EFAULT; > + > + return domain->ops->cache_invalidate(domain, dev, &inv_info); > } > EXPORT_SYMBOL_GPL(iommu_cache_invalidate); > > -int iommu_sva_bind_gpasid(struct iommu_domain *domain, > - struct device *dev, struct iommu_gpasid_bind_data *data) > +int iommu_sva_bind_gpasid(struct iommu_domain *domain, struct device *dev, > + void __user *udata) > { > + > + struct iommu_gpasid_bind_data data; > + unsigned long minsz, maxsz; > + > if (unlikely(!domain->ops->sva_bind_gpasid)) > return -ENODEV; > > - return domain->ops->sva_bind_gpasid(domain, dev, data); > + /* Current kernel data size is the max to be copied from user */ > + maxsz = sizeof(struct iommu_gpasid_bind_data); > + memset((void *)&data, 0, maxsz); > + > + /* > + * No new spaces can be added before the variable sized union, the > + * minimum size is the offset to the union. > + */ > + minsz = offsetof(struct iommu_gpasid_bind_data, vendor); > + > + /* Copy minsz from user to get flags and argsz */ > + if (copy_from_user(&data, udata, minsz)) > + return -EFAULT; > + > + /* Fields before variable size union is mandatory */ > + if (data.argsz < minsz) > + return -EINVAL; > + /* > + * User might be using a newer UAPI header, we shall let IOMMU vendor > + * driver decide on what size it needs. Since the guest PASID bind data > + * can be vendor specific, larger argsz could be the result of extension > + * for one vendor but it should not affect another vendor. > + */ > + if (data.argsz > maxsz) > + data.argsz = maxsz; > + > + /* Copy the remaining user data _after_ minsz */ > + if (copy_from_user((void *)&data + minsz, udata + minsz, > + data.argsz - minsz)) > + return -EFAULT; > + > + > + return domain->ops->sva_bind_gpasid(domain, dev, &data); > } > EXPORT_SYMBOL_GPL(iommu_sva_bind_gpasid); > > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 5f0b7859d2eb..a688fea42ae5 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -432,9 +432,10 @@ extern void iommu_detach_device(struct iommu_domain *domain, > struct device *dev); > extern int iommu_cache_invalidate(struct iommu_domain *domain, > struct device *dev, > - struct iommu_cache_invalidate_info *inv_info); > + void __user *uinfo); > + > extern int iommu_sva_bind_gpasid(struct iommu_domain *domain, > - struct device *dev, struct iommu_gpasid_bind_data *data); > + struct device *dev, void __user *udata); > extern int iommu_sva_unbind_gpasid(struct iommu_domain *domain, > struct device *dev, ioasid_t pasid); > extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev); > @@ -1062,7 +1063,7 @@ iommu_cache_invalidate(struct iommu_domain *domain, > return -ENODEV; > } > static inline int iommu_sva_bind_gpasid(struct iommu_domain *domain, > - struct device *dev, struct iommu_gpasid_bind_data *data) > + struct device *dev, void __user *udata) > { > return -ENODEV; > } >
Best regards, baolu
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