From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BBE84C433EC for ; Tue, 28 Jul 2020 19:20:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7F014207F5 for ; Tue, 28 Jul 2020 19:20:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HMRehFKP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732768AbgG1TT7 (ORCPT ); Tue, 28 Jul 2020 15:19:59 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:23726 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732751AbgG1TT6 (ORCPT ); Tue, 28 Jul 2020 15:19:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595963995; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=KNlgodQtoycgJgx4Tdv76N7CDy6zU/je+dFzrGLZZcc=; b=HMRehFKPL2kyPUEolAmN3HyseIRgAaI3DKvQK1KmYD3CjtWumW4cPXrv3W3IRWrQ5A2z27 MwKn/yv8h8MtrtGT3S1GWKqJnfrfULbRB3PtW4s5nnB/6SDtl52V2DHRc13+bdEpqJzTEx Ohk2QbyAVIDsqHqgqukzc2WTQXB85sM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-245-htCS3VBNOviA5Q76xVzaLw-1; Tue, 28 Jul 2020 15:19:51 -0400 X-MC-Unique: htCS3VBNOviA5Q76xVzaLw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 24A3E193F564; Tue, 28 Jul 2020 19:19:49 +0000 (UTC) Received: from x1.home (ovpn-112-71.phx2.redhat.com [10.3.112.71]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6815F19C4F; Tue, 28 Jul 2020 19:19:45 +0000 (UTC) Date: Tue, 28 Jul 2020 13:19:44 -0600 From: Alex Williamson To: Jacob Pan Cc: iommu@lists.linux-foundation.org, LKML , Joerg Roedel , "Lu Baolu" , David Woodhouse , Yi Liu , "Tian, Kevin" , Raj Ashok , "Christoph Hellwig" , Jean-Philippe Brucker , Eric Auger , Jonathan Corbet Subject: Re: [PATCH v6 5/6] iommu/uapi: Handle data and argsz filled by users Message-ID: <20200728131944.2e38e5fc@x1.home> In-Reply-To: <1595525140-23899-6-git-send-email-jacob.jun.pan@linux.intel.com> References: <1595525140-23899-1-git-send-email-jacob.jun.pan@linux.intel.com> <1595525140-23899-6-git-send-email-jacob.jun.pan@linux.intel.com> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 23 Jul 2020 10:25:39 -0700 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. > > 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 > Signed-off-by: Jacob Pan > --- > 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. > + 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. > + 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. > + 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) > + 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, 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; > }