Commit ba807c94 authored by Philipp Zabel's avatar Philipp Zabel
Browse files

drm/imx: fix use after free 

Component driver structures allocated with devm_kmalloc() in bind() are
freed automatically after unbind(). Since the contained drm structures
are accessed afterwards in drm_mode_config_cleanup(), move the
allocation into probe() to extend the driver structure's lifetime to the
lifetime of the device. This should eventually be changed to use drm
resource managed allocations with lifetime of the drm device.

We also need to ensure that all componets are available during the
unbind() so we need to call component_unbind_all() before we free
non-devres resources like planes.

Note this patch fixes the the use after free bug but introduces a
possible boot loop issue. The issue is triggered if the HDMI support is
enabled and a component driver always return -EPROBE_DEFER, see
discussion [1] for more details.

[1] https://lkml.org/lkml/2020/3/24/1467



Fixes: 17b5001b ("imx-drm: convert to componentised device support")
Signed-off-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
[m.felsch@pengutronix: fix imx_tve_probe()]
[m.felsch@pengutronix: resort component_unbind_all())
[m.felsch@pengutronix: adapt commit message]
Signed-off-by: default avatarMarco Felsch <m.felsch@pengutronix.de>
Signed-off-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
parent b3a9e3b9

drivers/gpu/drm/imx/dw_hdmi-imx.c

+10 −5
Original line number Diff line number Diff line
@@ -209,9 +209,8 @@ static int dw_hdmi_imx_bind(struct device *dev, struct device *master, 
	if (!pdev->dev.of_node)

		return -ENODEV;



	hdmi = devm_kzalloc(&pdev->dev, sizeof(*hdmi), GFP_KERNEL);

	if (!hdmi)

		return -ENOMEM;

	hdmi = dev_get_drvdata(dev);

	memset(hdmi, 0, sizeof(*hdmi));



	match = of_match_node(dw_hdmi_imx_dt_ids, pdev->dev.of_node);

	plat_data = match->data;
@@ -235,8 +234,6 @@ static int dw_hdmi_imx_bind(struct device *dev, struct device *master, 
	drm_encoder_helper_add(encoder, &dw_hdmi_imx_encoder_helper_funcs);

	drm_simple_encoder_init(drm, encoder, DRM_MODE_ENCODER_TMDS);



	platform_set_drvdata(pdev, hdmi);



	hdmi->hdmi = dw_hdmi_bind(pdev, encoder, plat_data);



	/*
@@ -266,6 +263,14 @@ static const struct component_ops dw_hdmi_imx_ops = { 


static int dw_hdmi_imx_probe(struct platform_device *pdev)

{

	struct imx_hdmi *hdmi;



	hdmi = devm_kzalloc(&pdev->dev, sizeof(*hdmi), GFP_KERNEL);

	if (!hdmi)

		return -ENOMEM;



	platform_set_drvdata(pdev, hdmi);



	return component_add(&pdev->dev, &dw_hdmi_imx_ops);

}

drivers/gpu/drm/imx/imx-drm-core.c

+2 −1
Original line number Diff line number Diff line
@@ -275,9 +275,10 @@ static void imx_drm_unbind(struct device *dev) 


	drm_kms_helper_poll_fini(drm);



	component_unbind_all(drm->dev, drm);



	drm_mode_config_cleanup(drm);



	component_unbind_all(drm->dev, drm);

	dev_set_drvdata(dev, NULL);



	drm_dev_put(drm);

drivers/gpu/drm/imx/imx-ldb.c

+10 −5
Original line number Diff line number Diff line
@@ -590,9 +590,8 @@ static int imx_ldb_bind(struct device *dev, struct device *master, void *data) 
	int ret;

	int i;



	imx_ldb = devm_kzalloc(dev, sizeof(*imx_ldb), GFP_KERNEL);

	if (!imx_ldb)

		return -ENOMEM;

	imx_ldb = dev_get_drvdata(dev);

	memset(imx_ldb, 0, sizeof(*imx_ldb));



	imx_ldb->regmap = syscon_regmap_lookup_by_phandle(np, "gpr");

	if (IS_ERR(imx_ldb->regmap)) {
@@ -700,8 +699,6 @@ static int imx_ldb_bind(struct device *dev, struct device *master, void *data) 
		}

	}



	dev_set_drvdata(dev, imx_ldb);



	return 0;



free_child:
@@ -733,6 +730,14 @@ static const struct component_ops imx_ldb_ops = { 


static int imx_ldb_probe(struct platform_device *pdev)

{

	struct imx_ldb *imx_ldb;



	imx_ldb = devm_kzalloc(&pdev->dev, sizeof(*imx_ldb), GFP_KERNEL);

	if (!imx_ldb)

		return -ENOMEM;



	platform_set_drvdata(pdev, imx_ldb);



	return component_add(&pdev->dev, &imx_ldb_ops);

}

drivers/gpu/drm/imx/imx-tve.c

+10 −5
Original line number Diff line number Diff line
@@ -542,9 +542,8 @@ static int imx_tve_bind(struct device *dev, struct device *master, void *data) 
	int irq;

	int ret;



	tve = devm_kzalloc(dev, sizeof(*tve), GFP_KERNEL);

	if (!tve)

		return -ENOMEM;

	tve = dev_get_drvdata(dev);

	memset(tve, 0, sizeof(*tve));



	tve->dev = dev;

	spin_lock_init(&tve->lock);
@@ -655,8 +654,6 @@ static int imx_tve_bind(struct device *dev, struct device *master, void *data) 
	if (ret)

		return ret;



	dev_set_drvdata(dev, tve);



	return 0;

}
@@ -676,6 +673,14 @@ static const struct component_ops imx_tve_ops = { 


static int imx_tve_probe(struct platform_device *pdev)

{

	struct imx_tve *tve;



	tve = devm_kzalloc(&pdev->dev, sizeof(*tve), GFP_KERNEL);

	if (!tve)

		return -ENOMEM;



	platform_set_drvdata(pdev, tve);



	return component_add(&pdev->dev, &imx_tve_ops);

}

drivers/gpu/drm/imx/ipuv3-crtc.c

+10 −11
Original line number Diff line number Diff line
@@ -438,21 +438,13 @@ static int ipu_drm_bind(struct device *dev, struct device *master, void *data) 
	struct ipu_client_platformdata *pdata = dev->platform_data;

	struct drm_device *drm = data;

	struct ipu_crtc *ipu_crtc;

	int ret;



	ipu_crtc = devm_kzalloc(dev, sizeof(*ipu_crtc), GFP_KERNEL);

	if (!ipu_crtc)

		return -ENOMEM;

	ipu_crtc = dev_get_drvdata(dev);

	memset(ipu_crtc, 0, sizeof(*ipu_crtc));



	ipu_crtc->dev = dev;



	ret = ipu_crtc_init(ipu_crtc, pdata, drm);

	if (ret)

		return ret;



	dev_set_drvdata(dev, ipu_crtc);



	return 0;

	return ipu_crtc_init(ipu_crtc, pdata, drm);

}



static void ipu_drm_unbind(struct device *dev, struct device *master,
@@ -474,6 +466,7 @@ static const struct component_ops ipu_crtc_ops = { 
static int ipu_drm_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct ipu_crtc *ipu_crtc;

	int ret;



	if (!dev->platform_data)
@@ -483,6 +476,12 @@ static int ipu_drm_probe(struct platform_device *pdev) 
	if (ret)

		return ret;



	ipu_crtc = devm_kzalloc(dev, sizeof(*ipu_crtc), GFP_KERNEL);

	if (!ipu_crtc)

		return -ENOMEM;



	dev_set_drvdata(dev, ipu_crtc);



	return component_add(dev, &ipu_crtc_ops);

}

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