On Wed, 24 Jun 2020 14:54:49 +0800 Lu Baolu <[email protected]> wrote:
> 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 <[email protected]> > > Signed-off-by: Jacob Pan <[email protected]> > > --- > > 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? > No need. The difference is that there is no vendor specific union for intel_iommu_sva_invalidate(). Generic flags are used to process invalidation data inside intel_iommu_sva_invalidate(). > > + > > 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 [Jacob Pan]
