linux-kernel - [PATCH v10 7/7] iommu/vt-d: Check UAPI data processed by IOMMU core

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Date:   Tue, 22 Sep 2020 13:17:02 -0700
From:   Jacob Pan <jacob.pan.linux@...il.com>
To:     iommu@...ts.linux-foundation.org,
        LKML <linux-kernel@...r.kernel.org>,
        Joerg Roedel <joro@...tes.org>,
        Alex Williamson <alex.williamson@...hat.com>,
        "Lu Baolu" <baolu.lu@...ux.intel.com>,
        David Woodhouse <dwmw2@...radead.org>,
        Jonathan Corbet <corbet@....net>
Cc:     linux-api@...r.kernel.org,
        Jean-Philippe Brucker <jean-philippe@...aro.com>,
        Eric Auger <eric.auger@...hat.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        Yi Liu <yi.l.liu@...el.com>,
        "Tian, Kevin" <kevin.tian@...el.com>,
        Raj Ashok <ashok.raj@...el.com>, Wu Hao <hao.wu@...el.com>,
        Yi Sun <yi.y.sun@...el.com>,
        Randy Dunlap <rdunlap@...radead.org>
Subject: [PATCH v10 7/7] iommu/vt-d: Check UAPI data processed by IOMMU core

IOMMU generic layer already does sanity checks on UAPI data for version
match and argsz range based on generic information.

This patch adjusts the following data checking responsibilities:
- removes the redundant version check from VT-d driver
- removes the check for vendor specific data size
- adds check for the use of reserved/undefined flags

Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
---
 drivers/iommu/intel/iommu.c |  3 +--
 drivers/iommu/intel/svm.c   | 11 +++++++++--
 include/uapi/linux/iommu.h  |  1 +
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 461f3a6864d4..18ed3b3c70d7 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5408,8 +5408,7 @@ intel_iommu_sva_invalidate(struct iommu_domain *domain, struct device *dev,
 	int ret = 0;
 	u64 size = 0;
 
-	if (!inv_info || !dmar_domain ||
-	    inv_info->version != IOMMU_CACHE_INVALIDATE_INFO_VERSION_1)
+	if (!inv_info || !dmar_domain)
 		return -EINVAL;
 
 	if (!dev || !dev_is_pci(dev))
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 99353d6468fa..0cb9a15f1112 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -284,8 +284,15 @@ int intel_svm_bind_gpasid(struct iommu_domain *domain, struct device *dev,
 	if (WARN_ON(!iommu) || !data)
 		return -EINVAL;
 
-	if (data->version != IOMMU_GPASID_BIND_VERSION_1 ||
-	    data->format != IOMMU_PASID_FORMAT_INTEL_VTD)
+	if (data->format != IOMMU_PASID_FORMAT_INTEL_VTD)
+		return -EINVAL;
+
+	/* IOMMU core ensures argsz is more than the start of the union */
+	if (data->argsz < offsetofend(struct iommu_gpasid_bind_data, vendor.vtd))
+		return -EINVAL;
+
+	/* Make sure no undefined flags are used in vendor data */
+	if (data->vendor.vtd.flags & ~(IOMMU_SVA_VTD_GPASID_LAST - 1))
 		return -EINVAL;
 
 	if (!dev_is_pci(dev))
diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
index c64bca5af419..1ebc23df4fbc 100644
--- a/include/uapi/linux/iommu.h
+++ b/include/uapi/linux/iommu.h
@@ -288,6 +288,7 @@ struct iommu_gpasid_bind_data_vtd {
 #define IOMMU_SVA_VTD_GPASID_PWT	(1 << 3) /* page-level write through */
 #define IOMMU_SVA_VTD_GPASID_EMTE	(1 << 4) /* extended mem type enable */
 #define IOMMU_SVA_VTD_GPASID_CD		(1 << 5) /* PASID-level cache disable */
+#define IOMMU_SVA_VTD_GPASID_LAST	(1 << 6)
 	__u64 flags;
 	__u32 pat;
 	__u32 emt;
-- 
2.7.4