Messages in this thread | | | Subject | Re: [PATCH v7 6/7] iommu/uapi: Handle data and argsz filled by users | From | Auger Eric <> | Date | Thu, 13 Aug 2020 11:30:51 +0200 |
| |
Hi Yi,
On 8/13/20 11:25 AM, Liu, Yi L wrote: > Hi Eric, > > >> From: Auger Eric <eric.auger@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.liu@intel.com/ > https://lore.kernel.org/kvm/1595917664-33276-12-git-send-email-yi.l.liu@intel.com/ Yep I know ;-) But this series mostly deals with iommu uapi rework. That's not a big deal though.
Thanks
Eric > > 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.liu@intel.com> >>> Signed-off-by: Jacob Pan <jacob.jun.pan@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.auger@redhat.com> >> >> Thanks >> >> Eric >
| |