[PATCH v3 0/2] HID: sensor: custom: Fix fields lifetime issues

[PATCH v3 0/2] HID: sensor: custom: Fix fields lifetime issues

[Haoxiang Li]

Hi,

This series fixes lifetime issues around sensor_inst->fields and the
sysfs attributes that can access it.

The first patch creates the field attributes before exposing enable_sensor
and removes enable_sensor before freeing the field attributes. This keeps
enable_sensor from accessing power_state and report_state pointers after
the fields array has been freed.

The second patch fixes the original field sysfs group leak on probe
failure by unwinding any field groups that were created before a later
sysfs_create_group() failure.

Changes in v3:
 - Move the enable_sensor registration reorder from patch 2 to patch 1.
 - Add a comment explaining why enable_sensor is removed before fields.
 - Add Reported-by and Link tags for the Sashiko review.
 - Keep patch 2 focused on the field sysfs group cleanup. Tanks, Jonathan!

Changes in v2:
 - Split the fix into two patches.
 - Unwind already-created field sysfs groups on failure. Thanks, Jiri!

Haoxiang Li (2):
  HID: sensor: custom: Fix use-after-free in enable_sensor
  HID: sensor: custom: Fix field sysfs group cleanup on failure

 drivers/hid/hid-sensor-custom.c | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)


base-commit: ef0c9f75a19532d7675384708fc8621e10850104
-- 
2.25.1

[PATCH v3 1/2] HID: sensor: custom: Fix use-after-free in enable_sensor

[Haoxiang Li]

enable_sensor_store() can call set_power_report_state(), which
dereferences sensor_inst->power_state and sensor_inst->report_state.
These pointers refer to entries in sensor_inst->fields.

Create the field attributes before exposing the enable_sensor sysfs
attribute, so enable_sensor cannot be accessed before the state it
depends on has been initialized.

On remove, delete enable_sensor before freeing the field attributes,
so a concurrent sysfs write cannot dereference freed memory through
power_state or report_state.

Reported-by: Sashiko AI Review <sashiko-bot@kernel.org>
Link: https://sashiko.dev/#/patchset/20260623021950.1736413-1-haoxiang_li2024@163.com?part=1
Fixes: 4a7de0519df5 ("HID: sensor: Custom and Generic sensor support")
Cc: stable@vger.kernel.org
Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
---
 drivers/hid/hid-sensor-custom.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/hid/hid-sensor-custom.c b/drivers/hid/hid-sensor-custom.c
index afffea894021..6b0da2e0e1c9 100644
--- a/drivers/hid/hid-sensor-custom.c
+++ b/drivers/hid/hid-sensor-custom.c
@@ -1005,26 +1005,26 @@ static int hid_sensor_custom_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = sysfs_create_group(&sensor_inst->pdev->dev.kobj,
-				 &enable_sensor_attr_group);
+	ret = hid_sensor_custom_add_attributes(sensor_inst);
 	if (ret)
 		goto err_remove_callback;
 
-	ret = hid_sensor_custom_add_attributes(sensor_inst);
+	ret = sysfs_create_group(&sensor_inst->pdev->dev.kobj,
+				 &enable_sensor_attr_group);
 	if (ret)
-		goto err_remove_group;
+		goto err_remove_attributes;
 
 	ret = hid_sensor_custom_dev_if_add(sensor_inst);
 	if (ret)
-		goto err_remove_attributes;
+		goto err_remove_group;
 
 	return 0;
 
-err_remove_attributes:
-	hid_sensor_custom_remove_attributes(sensor_inst);
 err_remove_group:
 	sysfs_remove_group(&sensor_inst->pdev->dev.kobj,
 			   &enable_sensor_attr_group);
+err_remove_attributes:
+	hid_sensor_custom_remove_attributes(sensor_inst);
 err_remove_callback:
 	sensor_hub_remove_callback(hsdev, hsdev->usage);
 
@@ -1042,9 +1042,10 @@ static void hid_sensor_custom_remove(struct platform_device *pdev)
 	}
 
 	hid_sensor_custom_dev_if_remove(sensor_inst);
-	hid_sensor_custom_remove_attributes(sensor_inst);
+	/* Remove enable_sensor first as it uses fields via power_state/report_state. */
 	sysfs_remove_group(&sensor_inst->pdev->dev.kobj,
 			   &enable_sensor_attr_group);
+	hid_sensor_custom_remove_attributes(sensor_inst);
 	sensor_hub_remove_callback(hsdev, hsdev->usage);
 }
 
-- 
2.25.1

Re: [PATCH v3 1/2] HID: sensor: custom: Fix use-after-free in enable_sensor

[srinivas pandruvada]

On Tue, 2026-07-07 at 15:15 +0800, Haoxiang Li wrote:
> enable_sensor_store() can call set_power_report_state(), which
> dereferences sensor_inst->power_state and sensor_inst->report_state.
> These pointers refer to entries in sensor_inst->fields.
> 
> Create the field attributes before exposing the enable_sensor sysfs
> attribute, so enable_sensor cannot be accessed before the state it
> depends on has been initialized.
> 
> On remove, delete enable_sensor before freeing the field attributes,
> so a concurrent sysfs write cannot dereference freed memory through
> power_state or report_state.
> 
> Reported-by: Sashiko AI Review <sashiko-bot@kernel.org>
> Link:
> https://sashiko.dev/#/patchset/20260623021950.1736413-1-haoxiang_li2024@163.com?part=1
> Fixes: 4a7de0519df5 ("HID: sensor: Custom and Generic sensor
> support")
> Cc: stable@vger.kernel.org
> Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>

Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

> ---
>  drivers/hid/hid-sensor-custom.c | 17 +++++++++--------
>  1 file changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/hid/hid-sensor-custom.c b/drivers/hid/hid-
> sensor-custom.c
> index afffea894021..6b0da2e0e1c9 100644
> --- a/drivers/hid/hid-sensor-custom.c
> +++ b/drivers/hid/hid-sensor-custom.c
> @@ -1005,26 +1005,26 @@ static int hid_sensor_custom_probe(struct
> platform_device *pdev)
>  		return ret;
>  	}
>  
> -	ret = sysfs_create_group(&sensor_inst->pdev->dev.kobj,
> -				 &enable_sensor_attr_group);
> +	ret = hid_sensor_custom_add_attributes(sensor_inst);
>  	if (ret)
>  		goto err_remove_callback;
>  
> -	ret = hid_sensor_custom_add_attributes(sensor_inst);
> +	ret = sysfs_create_group(&sensor_inst->pdev->dev.kobj,
> +				 &enable_sensor_attr_group);
>  	if (ret)
> -		goto err_remove_group;
> +		goto err_remove_attributes;
>  
>  	ret = hid_sensor_custom_dev_if_add(sensor_inst);
>  	if (ret)
> -		goto err_remove_attributes;
> +		goto err_remove_group;
>  
>  	return 0;
>  
> -err_remove_attributes:
> -	hid_sensor_custom_remove_attributes(sensor_inst);
>  err_remove_group:
>  	sysfs_remove_group(&sensor_inst->pdev->dev.kobj,
>  			   &enable_sensor_attr_group);
> +err_remove_attributes:
> +	hid_sensor_custom_remove_attributes(sensor_inst);
>  err_remove_callback:
>  	sensor_hub_remove_callback(hsdev, hsdev->usage);
>  
> @@ -1042,9 +1042,10 @@ static void hid_sensor_custom_remove(struct
> platform_device *pdev)
>  	}
>  
>  	hid_sensor_custom_dev_if_remove(sensor_inst);
> -	hid_sensor_custom_remove_attributes(sensor_inst);
> +	/* Remove enable_sensor first as it uses fields via
> power_state/report_state. */
>  	sysfs_remove_group(&sensor_inst->pdev->dev.kobj,
>  			   &enable_sensor_attr_group);
> +	hid_sensor_custom_remove_attributes(sensor_inst);
>  	sensor_hub_remove_callback(hsdev, hsdev->usage);
>  }
>  

[PATCH v3 2/2] HID: sensor: custom: Fix field sysfs group cleanup on failure

[Haoxiang Li]

hid_sensor_custom_add_attributes() creates one sysfs group for each
custom sensor field. If sysfs_create_group() fails after some groups
have already been created, the function returns the error without
removing the previously created groups.

Add a local unwind path to remove the groups that were already created.
With enable_sensor exposed only after the field attributes are ready,
this path can free sensor_inst->fields without leaving enable_sensor
able to access pointers into that array.

Fixes: 4a7de0519df5 ("HID: sensor: Custom and Generic sensor support")
Cc: stable@vger.kernel.org
Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>
---
 drivers/hid/hid-sensor-custom.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/hid/hid-sensor-custom.c b/drivers/hid/hid-sensor-custom.c
index 6b0da2e0e1c9..c2b425afd951 100644
--- a/drivers/hid/hid-sensor-custom.c
+++ b/drivers/hid/hid-sensor-custom.c
@@ -609,7 +609,7 @@ static int hid_sensor_custom_add_attributes(struct hid_sensor_custom
 					 &sensor_inst->fields[i].
 					 hid_custom_attribute_group);
 		if (ret)
-			break;
+			goto err_remove_groups;
 
 		/* For power or report field store indexes */
 		if (sensor_inst->fields[i].attribute.attrib_id ==
@@ -621,6 +621,13 @@ static int hid_sensor_custom_add_attributes(struct hid_sensor_custom
 	}
 
 	return ret;
+
+err_remove_groups:
+	while (--i >= 0)
+		sysfs_remove_group(&sensor_inst->pdev->dev.kobj,
+				   &sensor_inst->fields[i].hid_custom_attribute_group);
+	kfree(sensor_inst->fields);
+	return ret;
 }
 
 static void hid_sensor_custom_remove_attributes(struct hid_sensor_custom *
-- 
2.25.1

Re: [PATCH v3 2/2] HID: sensor: custom: Fix field sysfs group cleanup on failure

[srinivas pandruvada]

On Tue, 2026-07-07 at 15:15 +0800, Haoxiang Li wrote:
> hid_sensor_custom_add_attributes() creates one sysfs group for each
> custom sensor field. If sysfs_create_group() fails after some groups
> have already been created, the function returns the error without
> removing the previously created groups.
> 
> Add a local unwind path to remove the groups that were already
> created.
> With enable_sensor exposed only after the field attributes are ready,
> this path can free sensor_inst->fields without leaving enable_sensor
> able to access pointers into that array.
> 
> Fixes: 4a7de0519df5 ("HID: sensor: Custom and Generic sensor
> support")
> Cc: stable@vger.kernel.org
> Signed-off-by: Haoxiang Li <haoxiang_li2024@163.com>

Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

> ---
>  drivers/hid/hid-sensor-custom.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hid/hid-sensor-custom.c b/drivers/hid/hid-
> sensor-custom.c
> index 6b0da2e0e1c9..c2b425afd951 100644
> --- a/drivers/hid/hid-sensor-custom.c
> +++ b/drivers/hid/hid-sensor-custom.c
> @@ -609,7 +609,7 @@ static int
> hid_sensor_custom_add_attributes(struct hid_sensor_custom
>  					 &sensor_inst->fields[i].
>  					
> hid_custom_attribute_group);
>  		if (ret)
> -			break;
> +			goto err_remove_groups;
>  
>  		/* For power or report field store indexes */
>  		if (sensor_inst->fields[i].attribute.attrib_id ==
> @@ -621,6 +621,13 @@ static int
> hid_sensor_custom_add_attributes(struct hid_sensor_custom
>  	}
>  
>  	return ret;
> +
> +err_remove_groups:
> +	while (--i >= 0)
> +		sysfs_remove_group(&sensor_inst->pdev->dev.kobj,
> +				   &sensor_inst-
> >fields[i].hid_custom_attribute_group);
> +	kfree(sensor_inst->fields);
> +	return ret;
>  }
>  
>  static void hid_sensor_custom_remove_attributes(struct
> hid_sensor_custom *