On Tue, 28 Jul 2020 13:19:44 -0600 Alex Williamson <alex.william...@redhat.com> wrote:
> On Thu, 23 Jul 2020 10:25:39 -0700 > Jacob Pan <jacob.jun....@linux.intel.com> 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. > > > > 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 | 202 > > ++++++++++++++++++++++++++++++++++++++++++++++++-- > > include/linux/iommu.h | 28 ++++--- 2 files changed, 213 > > insertions(+), 17 deletions(-) > > > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > > index 3a913ce94a3d..1ce2a61058c6 100644 > > --- a/drivers/iommu/iommu.c > > +++ b/drivers/iommu/iommu.c > > @@ -1950,33 +1950,219 @@ 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 < 6; i++) { > > We could use sizeof(info->padding) here to avoid future issues > relative to the number of padding bytes. > yes, much better. > > + 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(inv_info.argsz, > > (u32)sizeof(inv_info)) - minsz)) > > Could use min_t() to cast both args to the specified type. > will do. min_t(u32, > > + 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 all supported format, for now just VT-d */ > > + mask = IOMMU_PASID_FORMAT_INTEL_VTD; > > + if (data->format & ~mask) > > data->format is not a bitmask though, it's an index, right? Should > defined formats be put into an enum with a last entry place holder for > this code to test against? If we end up with holes in the enum, I > guess we'd need to use special cases, ex: > > switch (data->format) { > case IOMMU_PASID_FORMAT_DEPRECATED0: > return -EINVAL; > case 0 ... IOMMU_PASID_FORMAT_LAST: > break; > default: > return -EINVAL; > } > > It seems strange and error prone anyway for common code to check > against a specific vendor format here. > Agreed, will change to enum with a last entry. > > + return -EINVAL; > > + > > + /* Check all flags */ > > + mask = IOMMU_SVA_GPASID_VAL; > > + if (data->flags & ~mask) > > + return -EINVAL; > > + > > + /* Check reserved padding fields */ > > + for (i = 0; i < 8; i++) { > > sizeof(data->padding) > will do. > > + 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(data->argsz, (u32)sizeof(*data)) - > > minsz)) > > min_t() here too. Thanks, > will do. Thanks! > Alex > > > + 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; > > } > [Jacob Pan]