Commit de83d461 authored by Johan Hovold's avatar Johan Hovold Committed by Joerg Roedel
Browse files

iommu/mediatek: fix use-after-free on probe deferral 



The driver is dropping the references taken to the larb devices during
probe after successful lookup as well as on errors. This can
potentially lead to a use-after-free in case a larb device has not yet
been bound to its driver so that the iommu driver probe defers.

Fix this by keeping the references as expected while the iommu driver is
bound.

Fixes: 26593928 ("iommu/mediatek: Add error path for loop of mm_dts_parse")
Cc: stable@vger.kernel.org
Cc: Yong Wu <yong.wu@mediatek.com>
Acked-by: default avatarRobin Murphy <robin.murphy@arm.com>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Reviewed-by: default avatarYong Wu <yong.wu@mediatek.com>
Reviewed-by: default avatarAngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: default avatarJoerg Roedel <joerg.roedel@amd.com>
parent b3f1ee18

drivers/iommu/mtk_iommu.c

+18 −7
Original line number Diff line number Diff line
@@ -1213,16 +1213,19 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m 
		}



		component_match_add(dev, match, component_compare_dev, &plarbdev->dev);

		platform_device_put(plarbdev);

	}



	if (!frst_avail_smicomm_node)

		return -EINVAL;

	if (!frst_avail_smicomm_node) {

		ret = -EINVAL;

		goto err_larbdev_put;

	}



	pcommdev = of_find_device_by_node(frst_avail_smicomm_node);

	of_node_put(frst_avail_smicomm_node);

	if (!pcommdev)

		return -ENODEV;

	if (!pcommdev) {

		ret = -ENODEV;

		goto err_larbdev_put;

	}

	data->smicomm_dev = &pcommdev->dev;



	link = device_link_add(data->smicomm_dev, dev,
@@ -1230,7 +1233,8 @@ static int mtk_iommu_mm_dts_parse(struct device *dev, struct component_match **m 
	platform_device_put(pcommdev);

	if (!link) {

		dev_err(dev, "Unable to link %s.\n", dev_name(data->smicomm_dev));

		return -EINVAL;

		ret = -EINVAL;

		goto err_larbdev_put;

	}

	return 0;
@@ -1402,8 +1406,12 @@ static int mtk_iommu_probe(struct platform_device *pdev) 
	iommu_device_sysfs_remove(&data->iommu);

out_list_del:

	list_del(&data->list);

	if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_MM))

	if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_MM)) {

		device_link_remove(data->smicomm_dev, dev);



		for (i = 0; i < MTK_LARB_NR_MAX; i++)

			put_device(data->larb_imu[i].dev);

	}

out_runtime_disable:

	pm_runtime_disable(dev);

	return ret;
@@ -1423,6 +1431,9 @@ static void mtk_iommu_remove(struct platform_device *pdev) 
	if (MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_MM)) {

		device_link_remove(data->smicomm_dev, &pdev->dev);

		component_master_del(&pdev->dev, &mtk_iommu_com_ops);



		for (i = 0; i < MTK_LARB_NR_MAX; i++)

			put_device(data->larb_imu[i].dev);

	}

	pm_runtime_disable(&pdev->dev);

	for (i = 0; i < data->plat_data->banks_num; i++) {