diff mbox

[v2] HID: rmi: check that report ids exist in the report_id_hash before accessing their size

Message ID 1405638885-8014-1-git-send-email-aduggan@synaptics.com (mailing list archive)
State New, archived
Delegated to: Jiri Kosina
Headers show

Commit Message

Andrew Duggan July 17, 2014, 11:14 p.m. UTC
It is possible that the hid-rmi driver could get loaded onto a device which does not have the
expected report ids. This should not happen because it would indicate that the hid-rmi driver is
not compatible with that device. However, if it does happen it should return an error from probe
instead of dereferencing a null pointer.

related bug:
https://bugzilla.kernel.org/show_bug.cgi?id=80091

Signed-off-by: Andrew Duggan <aduggan@synaptics.com>
---
Added hid_err messages as suggested by Benjamin. This fixes the null pointer dereference from
bug 80091 while the next patch addresses the binding issue in hid-core.

 drivers/hid/hid-rmi.c | 28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)

Comments

Benjamin Tissoires July 18, 2014, 1:03 p.m. UTC | #1
On Jul 17 2014 or thereabouts, Andrew Duggan wrote:
> It is possible that the hid-rmi driver could get loaded onto a device which does not have the
> expected report ids. This should not happen because it would indicate that the hid-rmi driver is
> not compatible with that device. However, if it does happen it should return an error from probe
> instead of dereferencing a null pointer.
> 
> related bug:
> https://bugzilla.kernel.org/show_bug.cgi?id=80091
> 
> Signed-off-by: Andrew Duggan <aduggan@synaptics.com>
> ---
> Added hid_err messages as suggested by Benjamin. This fixes the null pointer dereference from
> bug 80091 while the next patch addresses the binding issue in hid-core.

Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Cheers,
Benjamin

> 
>  drivers/hid/hid-rmi.c | 28 ++++++++++++++++++++++------
>  1 file changed, 22 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c
> index 3221a95..260be7a 100644
> --- a/drivers/hid/hid-rmi.c
> +++ b/drivers/hid/hid-rmi.c
> @@ -848,6 +848,8 @@ static int rmi_probe(struct hid_device *hdev, const struct hid_device_id *id)
>  	struct rmi_data *data = NULL;
>  	int ret;
>  	size_t alloc_size;
> +	struct hid_report *input_report;
> +	struct hid_report *output_report;
>  
>  	data = devm_kzalloc(&hdev->dev, sizeof(struct rmi_data), GFP_KERNEL);
>  	if (!data)
> @@ -866,12 +868,26 @@ static int rmi_probe(struct hid_device *hdev, const struct hid_device_id *id)
>  		return ret;
>  	}
>  
> -	data->input_report_size = (hdev->report_enum[HID_INPUT_REPORT]
> -		.report_id_hash[RMI_ATTN_REPORT_ID]->size >> 3)
> -		+ 1 /* report id */;
> -	data->output_report_size = (hdev->report_enum[HID_OUTPUT_REPORT]
> -		.report_id_hash[RMI_WRITE_REPORT_ID]->size >> 3)
> -		+ 1 /* report id */;
> +	input_report = hdev->report_enum[HID_INPUT_REPORT]
> +			.report_id_hash[RMI_ATTN_REPORT_ID];
> +	if (!input_report) {
> +		hid_err(hdev, "device does not have expected input report\n");
> +		ret = -ENODEV;
> +		return ret;
> +	}
> +
> +	data->input_report_size = (input_report->size >> 3) + 1 /* report id */;
> +
> +	output_report = hdev->report_enum[HID_OUTPUT_REPORT]
> +			.report_id_hash[RMI_WRITE_REPORT_ID];
> +	if (!output_report) {
> +		hid_err(hdev, "device does not have expected output report\n");
> +		ret = -ENODEV;
> +		return ret;
> +	}
> +
> +	data->output_report_size = (output_report->size >> 3)
> +					+ 1 /* report id */;
>  
>  	alloc_size = data->output_report_size + data->input_report_size;
>  
> -- 
> 1.9.1
> 
--
To unsubscribe from this list: send the line "unsubscribe linux-input" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Jiri Kosina July 29, 2014, 9:29 a.m. UTC | #2
On Thu, 17 Jul 2014, Andrew Duggan wrote:

> It is possible that the hid-rmi driver could get loaded onto a device which does not have the
> expected report ids. This should not happen because it would indicate that the hid-rmi driver is
> not compatible with that device. However, if it does happen it should return an error from probe
> instead of dereferencing a null pointer.
> 
> related bug:
> https://bugzilla.kernel.org/show_bug.cgi?id=80091
> 
> Signed-off-by: Andrew Duggan <aduggan@synaptics.com>

Applied, thanks.
diff mbox

Patch

diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c
index 3221a95..260be7a 100644
--- a/drivers/hid/hid-rmi.c
+++ b/drivers/hid/hid-rmi.c
@@ -848,6 +848,8 @@  static int rmi_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	struct rmi_data *data = NULL;
 	int ret;
 	size_t alloc_size;
+	struct hid_report *input_report;
+	struct hid_report *output_report;
 
 	data = devm_kzalloc(&hdev->dev, sizeof(struct rmi_data), GFP_KERNEL);
 	if (!data)
@@ -866,12 +868,26 @@  static int rmi_probe(struct hid_device *hdev, const struct hid_device_id *id)
 		return ret;
 	}
 
-	data->input_report_size = (hdev->report_enum[HID_INPUT_REPORT]
-		.report_id_hash[RMI_ATTN_REPORT_ID]->size >> 3)
-		+ 1 /* report id */;
-	data->output_report_size = (hdev->report_enum[HID_OUTPUT_REPORT]
-		.report_id_hash[RMI_WRITE_REPORT_ID]->size >> 3)
-		+ 1 /* report id */;
+	input_report = hdev->report_enum[HID_INPUT_REPORT]
+			.report_id_hash[RMI_ATTN_REPORT_ID];
+	if (!input_report) {
+		hid_err(hdev, "device does not have expected input report\n");
+		ret = -ENODEV;
+		return ret;
+	}
+
+	data->input_report_size = (input_report->size >> 3) + 1 /* report id */;
+
+	output_report = hdev->report_enum[HID_OUTPUT_REPORT]
+			.report_id_hash[RMI_WRITE_REPORT_ID];
+	if (!output_report) {
+		hid_err(hdev, "device does not have expected output report\n");
+		ret = -ENODEV;
+		return ret;
+	}
+
+	data->output_report_size = (output_report->size >> 3)
+					+ 1 /* report id */;
 
 	alloc_size = data->output_report_size + data->input_report_size;