linux-kernel - [PATCH v7 4/6] vfio/type1: check dma map request is within a valid iova range

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Date:   Wed, 26 Jun 2019 16:12:46 +0100
From:   Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>
To:     <alex.williamson@...hat.com>, <eric.auger@...hat.com>,
        <pmorel@...ux.vnet.ibm.com>
CC:     <kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <iommu@...ts.linux-foundation.org>, <linuxarm@...wei.com>,
        <john.garry@...wei.com>, <xuwei5@...ilicon.com>,
        <kevin.tian@...el.com>,
        Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>
Subject: [PATCH v7 4/6] vfio/type1: check dma map request is within a valid iova range

This checks and rejects any dma map request outside valid iova
range.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>
---
v6 --> v7

Addressed the case where a container with only an mdev device will
have an empty list(Suggested by Alex).
---
 drivers/vfio/vfio_iommu_type1.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index e872fb3a0f39..89ad0da7152c 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1050,6 +1050,27 @@ static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma,
 	return ret;
 }
 
+/*
+ * Check dma map request is within a valid iova range
+ */
+static bool vfio_iommu_iova_dma_valid(struct vfio_iommu *iommu,
+				      dma_addr_t start, dma_addr_t end)
+{
+	struct list_head *iova = &iommu->iova_list;
+	struct vfio_iova *node;
+
+	list_for_each_entry(node, iova, list) {
+		if (start >= node->start && end <= node->end)
+			return true;
+	}
+
+	/*
+	 * Check for list_empty() as well since a container with
+	 * only an mdev device will have an empty list.
+	 */
+	return list_empty(&iommu->iova_list);
+}
+
 static int vfio_dma_do_map(struct vfio_iommu *iommu,
 			   struct vfio_iommu_type1_dma_map *map)
 {
@@ -1093,6 +1114,11 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
 		goto out_unlock;
 	}
 
+	if (!vfio_iommu_iova_dma_valid(iommu, iova, iova + size - 1)) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
 	dma = kzalloc(sizeof(*dma), GFP_KERNEL);
 	if (!dma) {
 		ret = -ENOMEM;
-- 
2.17.1