[PATCH AUTOSEL 6.11 129/244] drm/stm: Avoid use-after-free issues with crtc and plane

Sasha Levin
2024-09-25T11:42:51Z

From: Katya Orlova <e.orlova@ispras.ru>

[ Upstream commit 19dd9780b7ac673be95bf6fd6892a184c9db611f ]

ltdc_load() calls functions drm_crtc_init_with_planes(),
drm_universal_plane_init() and drm_encoder_init(). These functions
should not be called with parameters allocated with devm_kzalloc()
to avoid use-after-free issues [1].

Use allocations managed by the DRM framework.

Found by Linux Verification Center (linuxtesting.org).

[1]
https://lore.kernel.org/lkml/u366i76e3qhh3ra5oxrtngjtm2u5lterkekcz6y2jkndhuxzli@diujon4h7qwb/

Signed-off-by: Katya Orlova <e.orlova@ispras.ru>
Acked-by: Raphaël Gallais-Pou <raphael.gallais-pou@foss.st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240216125040.8968-1-e.orlova@ispras.ru
Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/stm/drv.c | 3 +-
drivers/gpu/drm/stm/ltdc.c | 73 ++++++++++----------------------------
2 files changed, 20 insertions(+), 56 deletions(-)

diff --git a/drivers/gpu/drm/stm/drv.c b/drivers/gpu/drm/stm/drv.c
index e8523abef27a5..152bec2c02385 100644
--- a/drivers/gpu/drm/stm/drv.c
+++ b/drivers/gpu/drm/stm/drv.c
@@ -25,6 +25,7 @@
#include <drm/drm_module.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_vblank.h>
+#include <drm/drm_managed.h>

#include "ltdc.h"

@@ -75,7 +76,7 @@ static int drv_load(struct drm_device *ddev)

DRM_DEBUG("%s\n", __func__);

- ldev = devm_kzalloc(ddev->dev, sizeof(*ldev), GFP_KERNEL);
+ ldev = drmm_kzalloc(ddev, sizeof(*ldev), GFP_KERNEL);
if (!ldev)
return -ENOMEM;

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index 5576fdae49623..eeaabb4e10d3e 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -36,6 +36,7 @@
#include <drm/drm_probe_helper.h>
#include <drm/drm_simple_kms_helper.h>
#include <drm/drm_vblank.h>
+#include <drm/drm_managed.h>

#include <video/videomode.h>

@@ -1199,7 +1200,6 @@ static void ltdc_crtc_atomic_print_state(struct drm_printer *p,
}

static const struct drm_crtc_funcs ltdc_crtc_funcs = {
- .destroy = drm_crtc_cleanup,
.set_config = drm_atomic_helper_set_config,
.page_flip = drm_atomic_helper_page_flip,
.reset = drm_atomic_helper_crtc_reset,
@@ -1212,7 +1212,6 @@ static const struct drm_crtc_funcs ltdc_crtc_funcs = {
};

static const struct drm_crtc_funcs ltdc_crtc_with_crc_support_funcs = {
- .destroy = drm_crtc_cleanup,
.set_config = drm_atomic_helper_set_config,
.page_flip = drm_atomic_helper_page_flip,
.reset = drm_atomic_helper_crtc_reset,
@@ -1545,7 +1544,6 @@ static void ltdc_plane_atomic_print_state(struct drm_printer *p,
static const struct drm_plane_funcs ltdc_plane_funcs = {
.update_plane = drm_atomic_helper_update_plane,
.disable_plane = drm_atomic_helper_disable_plane,
- .destroy = drm_plane_cleanup,
.reset = drm_atomic_helper_plane_reset,
.atomic_duplicate_state = drm_atomic_helper_plane_duplicate_state,
.atomic_destroy_state = drm_atomic_helper_plane_destroy_state,
@@ -1572,7 +1570,6 @@ static struct drm_plane *ltdc_plane_create(struct drm_device *ddev,
const u64 *modifiers = ltdc_format_modifiers;
u32 lofs = index * LAY_OFS;
u32 val;
- int ret;

/* Allocate the biggest size according to supported color formats */
formats = devm_kzalloc(dev, (ldev->caps.pix_fmt_nb +
@@ -1613,14 +1610,10 @@ static struct drm_plane *ltdc_plane_create(struct drm_device *ddev,
}
}

- plane = devm_kzalloc(dev, sizeof(*plane), GFP_KERNEL);
- if (!plane)
- return NULL;
-
- ret = drm_universal_plane_init(ddev, plane, possible_crtcs,
- &ltdc_plane_funcs, formats, nb_fmt,
- modifiers, type, NULL);
- if (ret < 0)
+ plane = drmm_universal_plane_alloc(ddev, struct drm_plane, dev,
+ possible_crtcs, &ltdc_plane_funcs, formats,
+ nb_fmt, modifiers, type, NULL);
+ if (IS_ERR(plane))
return NULL;

if (ldev->caps.ycbcr_input) {
@@ -1643,15 +1636,6 @@ static struct drm_plane *ltdc_plane_create(struct drm_device *ddev,
return plane;
}

-static void ltdc_plane_destroy_all(struct drm_device *ddev)
-{
- struct drm_plane *plane, *plane_temp;
-
- list_for_each_entry_safe(plane, plane_temp,
- &ddev->mode_config.plane_list, head)
- drm_plane_cleanup(plane);
-}
-
static int ltdc_crtc_init(struct drm_device *ddev, struct drm_crtc *crtc)
{
struct ltdc_device *ldev = ddev->dev_private;
@@ -1677,14 +1661,14 @@ static int ltdc_crtc_init(struct drm_device *ddev, struct drm_crtc *crtc)

/* Init CRTC according to its hardware features */
if (ldev->caps.crc)
- ret = drm_crtc_init_with_planes(ddev, crtc, primary, NULL,
- &ltdc_crtc_with_crc_support_funcs, NULL);
+ ret = drmm_crtc_init_with_planes(ddev, crtc, primary, NULL,
+ &ltdc_crtc_with_crc_support_funcs, NULL);
else
- ret = drm_crtc_init_with_planes(ddev, crtc, primary, NULL,
- &ltdc_crtc_funcs, NULL);
+ ret = drmm_crtc_init_with_planes(ddev, crtc, primary, NULL,
+ &ltdc_crtc_funcs, NULL);
if (ret) {
DRM_ERROR("Can not initialize CRTC\n");
- goto cleanup;
+ return ret;
}

drm_crtc_helper_add(crtc, &ltdc_crtc_helper_funcs);
@@ -1698,9 +1682,8 @@ static int ltdc_crtc_init(struct drm_device *ddev, struct drm_crtc *crtc)
for (i = 1; i < ldev->caps.nb_layers; i++) {
overlay = ltdc_plane_create(ddev, DRM_PLANE_TYPE_OVERLAY, i);
if (!overlay) {
- ret = -ENOMEM;
DRM_ERROR("Can not create overlay plane %d\n", i);
- goto cleanup;
+ return -ENOMEM;
}
if (ldev->caps.dynamic_zorder)
drm_plane_create_zpos_property(overlay, i, 0, ldev->caps.nb_layers - 1);
@@ -1713,10 +1696,6 @@ static int ltdc_crtc_init(struct drm_device *ddev, struct drm_crtc *crtc)
}

return 0;
-
-cleanup:
- ltdc_plane_destroy_all(ddev);
- return ret;
}

static void ltdc_encoder_disable(struct drm_encoder *encoder)
@@ -1776,23 +1755,19 @@ static int ltdc_encoder_init(struct drm_device *ddev, struct drm_bridge *bridge)
struct drm_encoder *encoder;
int ret;

- encoder = devm_kzalloc(ddev->dev, sizeof(*encoder), GFP_KERNEL);
- if (!encoder)
- return -ENOMEM;
+ encoder = drmm_simple_encoder_alloc(ddev, struct drm_encoder, dev,
+ DRM_MODE_ENCODER_DPI);
+ if (IS_ERR(encoder))
+ return PTR_ERR(encoder);

encoder->possible_crtcs = CRTC_MASK;
encoder->possible_clones = 0; /* No cloning support */

- drm_simple_encoder_init(ddev, encoder, DRM_MODE_ENCODER_DPI);
-
drm_encoder_helper_add(encoder, &ltdc_encoder_helper_funcs);

ret = drm_bridge_attach(encoder, bridge, NULL, 0);
- if (ret) {
- if (ret != -EPROBE_DEFER)
- drm_encoder_cleanup(encoder);
+ if (ret)
return ret;
- }

DRM_DEBUG_DRIVER("Bridge encoder:%d created\n", encoder->base.id);

@@ -1962,8 +1937,7 @@ int ltdc_load(struct drm_device *ddev)
goto err;

if (panel) {
- bridge = drm_panel_bridge_add_typed(panel,
- DRM_MODE_CONNECTOR_DPI);
+ bridge = drmm_panel_bridge_add(ddev, panel);
if (IS_ERR(bridge)) {
DRM_ERROR("panel-bridge endpoint %d\n", i);
ret = PTR_ERR(bridge);
@@ -2045,7 +2019,7 @@ int ltdc_load(struct drm_device *ddev)
}
}

- crtc = devm_kzalloc(dev, sizeof(*crtc), GFP_KERNEL);
+ crtc = drmm_kzalloc(ddev, sizeof(*crtc), GFP_KERNEL);
if (!crtc) {
DRM_ERROR("Failed to allocate crtc\n");
ret = -ENOMEM;
@@ -2072,9 +2046,6 @@ int ltdc_load(struct drm_device *ddev)

return 0;
err:
- for (i = 0; i < nb_endpoints; i++)
- drm_of_panel_bridge_remove(ddev->dev->of_node, 0, i);
-
clk_disable_unprepare(ldev->pixel_clk);

return ret;
@@ -2082,16 +2053,8 @@ int ltdc_load(struct drm_device *ddev)

void ltdc_unload(struct drm_device *ddev)
{
- struct device *dev = ddev->dev;
- int nb_endpoints, i;
-
DRM_DEBUG_DRIVER("\n");

- nb_endpoints = of_graph_get_endpoint_count(dev->of_node);
-
- for (i = 0; i < nb_endpoints; i++)
- drm_of_panel_bridge_remove(ddev->dev->of_node, 0, i);
-
pm_runtime_disable(ddev->dev);
}

--
2.43.0