Hi Eric,
> From: Auger Eric <eric.au...@redhat.com> > Sent: Thursday, August 13, 2020 5:12 PM > > Hi Jacob, > > On 7/30/20 2:21 AM, Jacob Pan wrote: > > IOMMU user APIs are responsible for processing user data. This patch > > changes the interface such that user pointers can be passed into IOMMU > > code directly. Separate kernel APIs without user pointers are introduced > > for in-kernel users of the UAPI functionality. > This is just done for a single function, ie. iommu_sva_unbind_gpasid. > > If I am not wrong there is no user of this latter after applying the > whole series? If correct you may remove it at this stage? the user of this function is in vfio. And it is the same with iommu_uapi_sva_bind/unbind_gpasid() and iommu_uapi_cache_invalidate(). https://lore.kernel.org/kvm/1595917664-33276-11-git-send-email-yi.l....@intel.com/ https://lore.kernel.org/kvm/1595917664-33276-12-git-send-email-yi.l....@intel.com/ Regards, Yi Liu > > > > IOMMU UAPI data has a user filled argsz field which indicates the data > > length of the structure. 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, resulting in possible argsz increase. > > Backward compatibility is ensured based on size and flags (or > > the functional equivalent fields) checking. > > > > This patch adds sanity checks in the IOMMU layer. In addition to argsz, > > reserved/unused fields in padding, flags, and version are also checked. > > Details are documented in Documentation/userspace-api/iommu.rst > > > > Signed-off-by: Liu Yi L <yi.l....@intel.com> > > Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com> > > --- > > drivers/iommu/iommu.c | 201 > ++++++++++++++++++++++++++++++++++++++++++++++++-- > > include/linux/iommu.h | 28 ++++--- > > 2 files changed, 212 insertions(+), 17 deletions(-) > > > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > > index 3a913ce94a3d..1ee55c4b3a3a 100644 > > --- a/drivers/iommu/iommu.c > > +++ b/drivers/iommu/iommu.c > > @@ -1950,33 +1950,218 @@ int iommu_attach_device(struct iommu_domain > *domain, struct device *dev) > > } > > EXPORT_SYMBOL_GPL(iommu_attach_device); > > > > +/* > > + * Check flags and other user provided data for valid combinations. We also > > + * make sure no reserved fields or unused flags are set. This is to ensure > > + * not breaking userspace in the future when these fields or flags are > > used. > > + */ > > +static int iommu_check_cache_invl_data(struct iommu_cache_invalidate_info > *info) > > +{ > > + u32 mask; > > + int i; > > + > > + if (info->version != IOMMU_CACHE_INVALIDATE_INFO_VERSION_1) > > + return -EINVAL; > > + > > + mask = (1 << IOMMU_CACHE_INV_TYPE_NR) - 1; > > + if (info->cache & ~mask) > > + return -EINVAL; > > + > > + if (info->granularity >= IOMMU_INV_GRANU_NR) > > + return -EINVAL; > > + > > + switch (info->granularity) { > > + case IOMMU_INV_GRANU_ADDR: > > + if (info->cache & IOMMU_CACHE_INV_TYPE_PASID) > > + return -EINVAL; > > + > > + mask = IOMMU_INV_ADDR_FLAGS_PASID | > > + IOMMU_INV_ADDR_FLAGS_ARCHID | > > + IOMMU_INV_ADDR_FLAGS_LEAF; > > + > > + if (info->granu.addr_info.flags & ~mask) > > + return -EINVAL; > > + break; > > + case IOMMU_INV_GRANU_PASID: > > + mask = IOMMU_INV_PASID_FLAGS_PASID | > > + IOMMU_INV_PASID_FLAGS_ARCHID; > > + if (info->granu.pasid_info.flags & ~mask) > > + return -EINVAL; > > + > > + break; > > + case IOMMU_INV_GRANU_DOMAIN: > > + if (info->cache & IOMMU_CACHE_INV_TYPE_DEV_IOTLB) > > + return -EINVAL; > > + break; > > + default: > > + return -EINVAL; > > + } > > + > > + /* Check reserved padding fields */ > > + for (i = 0; i < sizeof(info->padding); i++) { > > + if (info->padding[i]) > > + return -EINVAL; > > + } > > + > > + return 0; > > +} > > + > > int iommu_uapi_cache_invalidate(struct iommu_domain *domain, struct device > *dev, > > - struct iommu_cache_invalidate_info *inv_info) > > + void __user *uinfo) > > { > > + struct iommu_cache_invalidate_info inv_info = { 0 }; > > + u32 minsz; > > + int ret = 0; > > + > > if (unlikely(!domain->ops->cache_invalidate)) > > return -ENODEV; > > > - return domain->ops->cache_invalidate(domain, dev, inv_info); > > + /* > > + * 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; > > + > > + /* PASID and address granu require additional info beyond minsz */ > > + if (inv_info.argsz == minsz && > > + ((inv_info.granularity == IOMMU_INV_GRANU_PASID) || > > + (inv_info.granularity == IOMMU_INV_GRANU_ADDR))) > > + return -EINVAL; > > + > > + if (inv_info.granularity == IOMMU_INV_GRANU_PASID && > > + inv_info.argsz < offsetofend(struct iommu_cache_invalidate_info, > granu.pasid_info)) > > + return -EINVAL; > > + > > + if (inv_info.granularity == IOMMU_INV_GRANU_ADDR && > > + inv_info.argsz < offsetofend(struct iommu_cache_invalidate_info, > granu.addr_info)) > > + return -EINVAL; > > + > > + /* > > + * User might be using a newer UAPI header which has a larger data > > + * size, we shall support the existing flags within the current > > + * size. Copy the remaining user data _after_ minsz but not more > > + * than the current kernel supported size. > > + */ > > + if (copy_from_user((void *)&inv_info + minsz, uinfo + minsz, > > + min_t(u32, inv_info.argsz, sizeof(inv_info)) - > > minsz)) > > + return -EFAULT; > > + > > + /* Now the argsz is validated, check the content */ > > + ret = iommu_check_cache_invl_data(&inv_info); > > + if (ret) > > + return ret; > > + > > + return domain->ops->cache_invalidate(domain, dev, &inv_info); > > } > > EXPORT_SYMBOL_GPL(iommu_uapi_cache_invalidate); > > > > -int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain, > > - struct device *dev, struct iommu_gpasid_bind_data > *data) > > +static int iommu_check_bind_data(struct iommu_gpasid_bind_data *data) > > +{ > > + u32 mask; > > + int i; > > + > > + if (data->version != IOMMU_GPASID_BIND_VERSION_1) > > + return -EINVAL; > > + > > + /* Check the range of supported formats */ > > + if (data->format >= IOMMU_PASID_FORMAT_LAST) > > + return -EINVAL; > > + > > + /* Check all flags */ > > + mask = IOMMU_SVA_GPASID_VAL; > > + if (data->flags & ~mask) > > + return -EINVAL; > > + > > + /* Check reserved padding fields */ > > + for (i = 0; i < sizeof(data->padding); i++) { > > + if (data->padding[i]) > > + return -EINVAL; > > + } > > + > > + return 0; > > +} > > + > > +static int iommu_sva_prepare_bind_data(void __user *udata, > > + struct iommu_gpasid_bind_data *data) > > { > > + u32 minsz; > > + > > + /* > > + * 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. > > + * Copy the remaining user data _after_ minsz > > + */ > > + if (copy_from_user((void *)data + minsz, udata + minsz, > > + min_t(u32, data->argsz, sizeof(*data)) - minsz)) > > + return -EFAULT; > > + > > + return iommu_check_bind_data(data); > > +} > > + > > +int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain, struct device > *dev, > > + void __user *udata) > > +{ > > + struct iommu_gpasid_bind_data data = { 0 }; > > + int ret; > > + > > if (unlikely(!domain->ops->sva_bind_gpasid)) > > return -ENODEV; > > > > - return domain->ops->sva_bind_gpasid(domain, dev, data); > > + ret = iommu_sva_prepare_bind_data(udata, &data); > > + if (ret) > > + return ret; > > + > > + return domain->ops->sva_bind_gpasid(domain, dev, &data); > > } > > EXPORT_SYMBOL_GPL(iommu_uapi_sva_bind_gpasid); > > > > -int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain, struct device > *dev, > > - ioasid_t pasid) > > +int iommu_sva_unbind_gpasid(struct iommu_domain *domain, struct device > > *dev, > > + struct iommu_gpasid_bind_data *data) > > { > > if (unlikely(!domain->ops->sva_unbind_gpasid)) > > return -ENODEV; > > > > - return domain->ops->sva_unbind_gpasid(dev, pasid); > > + return domain->ops->sva_unbind_gpasid(dev, data->hpasid); > > +} > > +EXPORT_SYMBOL_GPL(iommu_sva_unbind_gpasid); > > + > > +int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain, struct device > *dev, > > + void __user *udata) > > +{ > > + struct iommu_gpasid_bind_data data = { 0 }; > > + int ret; > > + > > + if (unlikely(!domain->ops->sva_bind_gpasid)) > > + return -ENODEV; > > + > > + ret = iommu_sva_prepare_bind_data(udata, &data); > > + if (ret) > > + return ret; > > + > > + return iommu_sva_unbind_gpasid(domain, dev, &data); > > } > > EXPORT_SYMBOL_GPL(iommu_uapi_sva_unbind_gpasid); > > > > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > > index 2dcc1a33f6dc..4a02c9e09048 100644 > > --- a/include/linux/iommu.h > > +++ b/include/linux/iommu.h > > @@ -432,11 +432,14 @@ extern void iommu_detach_device(struct > iommu_domain *domain, > > struct device *dev); > > extern int iommu_uapi_cache_invalidate(struct iommu_domain *domain, > > struct device *dev, > > - struct iommu_cache_invalidate_info > > *inv_info); > > + void __user *uinfo); > > + > > extern int iommu_uapi_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_uapi_sva_unbind_gpasid(struct iommu_domain *domain, > > - struct device *dev, ioasid_t pasid); > > + struct device *dev, void __user *udata); > > +extern int iommu_sva_unbind_gpasid(struct iommu_domain *domain, > > + struct device *dev, struct > iommu_gpasid_bind_data *data); > > extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev); > > extern struct iommu_domain *iommu_get_dma_domain(struct device *dev); > > extern int iommu_map(struct iommu_domain *domain, unsigned long iova, > > @@ -1054,22 +1057,29 @@ static inline int iommu_sva_get_pasid(struct > iommu_sva *handle) > > return IOMMU_PASID_INVALID; > > } > > > > -static inline int iommu_uapi_cache_invalidate(struct iommu_domain *domain, > > - struct device *dev, > > - struct iommu_cache_invalidate_info > *inv_info) > > +static inline int > > +iommu_uapi_cache_invalidate(struct iommu_domain *domain, > > + struct device *dev, > > + struct iommu_cache_invalidate_info *inv_info) > > { > > return -ENODEV; > > } > > > > static inline int iommu_uapi_sva_bind_gpasid(struct iommu_domain *domain, > > - struct device *dev, > > - struct iommu_gpasid_bind_data > > *data) > > + struct device *dev, void __user > > *udata) > > { > > return -ENODEV; > > } > > > > static inline int iommu_uapi_sva_unbind_gpasid(struct iommu_domain *domain, > > - struct device *dev, int pasid) > > + struct device *dev, void __user > > *udata) > > +{ > > + return -ENODEV; > > +} > > + > > +static inline int iommu_sva_unbind_gpasid(struct iommu_domain *domain, > > + struct device *dev, > > + struct iommu_gpasid_bind_data *data) > > { > > return -ENODEV; > > } > > > Otherwise looks good to me > Reviewed-by: Eric Auger <eric.au...@redhat.com> > > Thanks > > Eric
