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authorAndrew Duggan <aduggan@synaptics.com>2014-07-17 16:14:44 -0700
committerJiri Kosina <jkosina@suse.cz>2014-07-29 11:28:49 +0200
commitdd3edeb6a0267029bc3ffc480fb41dffb9081844 (patch)
tree85754fa3a11469707d9c67977df1ec7bec6c6c5e /drivers/hid
parent01a5f8a401a2a525b9546d65ddf69aaba37f288d (diff)
downloadlinux-dd3edeb6a0267029bc3ffc480fb41dffb9081844.tar.gz
HID: rmi: check that report ids exist in the report_id_hash before accessing their size
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>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'drivers/hid')
-rw-r--r--drivers/hid/hid-rmi.c28
1 files changed, 22 insertions, 6 deletions
diff --git a/drivers/hid/hid-rmi.c b/drivers/hid/hid-rmi.c
index 2c3524bacca6..0dc25142f451 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;