iommu: Fix wrong freeing of iommu_device->dev

The struct iommu_device has a 'struct device' embedded into
it, not as a pointer, but the whole struct. In the
conversion of the iommu drivers to use struct iommu_device
it was forgotten that the relase function for that struct
device simply calls kfree() on the pointer.

This frees memory that was never allocated and causes memory
corruption.

To fix this issue, use a pointer to struct device instead of
embedding the whole struct. This needs some updates in the
iommu sysfs code as well as the Intel VT-d and AMD IOMMU
driver.

Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Fixes: 39ab9555c241 ('iommu: Add sysfs bindings for struct iommu_device')
Cc: stable@vger.kernel.org # >= v4.11
Signed-off-by: Joerg Roedel <jroedel@suse.de>

3 files changed, 26 insertions, 14 deletions

diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index 294a409..d6b873b 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -574,7 +574,9 @@ struct amd_iommu {
 
 static inline struct amd_iommu *dev_to_amd_iommu(struct device *dev)
 {
-	return container_of(dev, struct amd_iommu, iommu.dev);
+	struct iommu_device *iommu = dev_to_iommu_device(dev);
+
+	return container_of(iommu, struct amd_iommu, iommu);
 }
 
 #define ACPIHID_UID_LEN 256
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 687f18f..3e8636f 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4736,7 +4736,9 @@ static void intel_disable_iommus(void)
 
 static inline struct intel_iommu *dev_to_intel_iommu(struct device *dev)
 {
-	return container_of(dev, struct intel_iommu, iommu.dev);
+	struct iommu_device *iommu_dev = dev_to_iommu_device(dev);
+
+	return container_of(iommu_dev, struct intel_iommu, iommu);
 }
 
 static ssize_t intel_iommu_show_version(struct device *dev,
diff --git a/drivers/iommu/iommu-sysfs.c b/drivers/iommu/iommu-sysfs.c
index c58351e..36d1a7c 100644
--- a/drivers/iommu/iommu-sysfs.c
+++ b/drivers/iommu/iommu-sysfs.c
@@ -62,32 +62,40 @@ int iommu_device_sysfs_add(struct iommu_device *iommu,
 	va_list vargs;
 	int ret;
 
-	device_initialize(&iommu->dev);
+	iommu->dev = kzalloc(sizeof(*iommu->dev), GFP_KERNEL);
+	if (!iommu->dev)
+		return -ENOMEM;
 
-	iommu->dev.class = &iommu_class;
-	iommu->dev.parent = parent;
-	iommu->dev.groups = groups;
+	device_initialize(iommu->dev);
+
+	iommu->dev->class = &iommu_class;
+	iommu->dev->parent = parent;
+	iommu->dev->groups = groups;
 
 	va_start(vargs, fmt);
-	ret = kobject_set_name_vargs(&iommu->dev.kobj, fmt, vargs);
+	ret = kobject_set_name_vargs(&iommu->dev->kobj, fmt, vargs);
 	va_end(vargs);
 	if (ret)
 		goto error;
 
-	ret = device_add(&iommu->dev);
+	ret = device_add(iommu->dev);
 	if (ret)
 		goto error;
 
+	dev_set_drvdata(iommu->dev, iommu);
+
 	return 0;
 
 error:
-	put_device(&iommu->dev);
+	put_device(iommu->dev);
 	return ret;
 }
 
 void iommu_device_sysfs_remove(struct iommu_device *iommu)
 {
-	device_unregister(&iommu->dev);
+	dev_set_drvdata(iommu->dev, NULL);
+	device_unregister(iommu->dev);
+	iommu->dev = NULL;
 }
 /*
  * IOMMU drivers can indicate a device is managed by a given IOMMU using
@@ -102,14 +110,14 @@ int iommu_device_link(struct iommu_device *iommu, struct device *link)
 	if (!iommu || IS_ERR(iommu))
 		return -ENODEV;
 
-	ret = sysfs_add_link_to_group(&iommu->dev.kobj, "devices",
+	ret = sysfs_add_link_to_group(&iommu->dev->kobj, "devices",
 				      &link->kobj, dev_name(link));
 	if (ret)
 		return ret;
 
-	ret = sysfs_create_link_nowarn(&link->kobj, &iommu->dev.kobj, "iommu");
+	ret = sysfs_create_link_nowarn(&link->kobj, &iommu->dev->kobj, "iommu");
 	if (ret)
-		sysfs_remove_link_from_group(&iommu->dev.kobj, "devices",
+		sysfs_remove_link_from_group(&iommu->dev->kobj, "devices",
 					     dev_name(link));
 
 	return ret;
@@ -121,5 +129,5 @@ void iommu_device_unlink(struct iommu_device *iommu, struct device *link)
 		return;
 
 	sysfs_remove_link(&link->kobj, "iommu");
-	sysfs_remove_link_from_group(&iommu->dev.kobj, "devices", dev_name(link));
+	sysfs_remove_link_from_group(&iommu->dev->kobj, "devices", dev_name(link));
 }