HID: LG: validate HID output report details

A HID device could send a malicious output report that would cause the
lg, lg3, and lg4 HID drivers to write beyond the output report allocation
during an event, causing a heap overflow:

[  325.245240] usb 1-1: New USB device found, idVendor=046d, idProduct=c287
...
[  414.518960] BUG kmalloc-4096 (Not tainted): Redzone overwritten

Additionally, while lg2 did correctly validate the report details, it was
cleaned up and shortened.

CVE-2013-2893

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 3 insertions, 16 deletions

diff --git a/drivers/hid/hid-lg2ff.c b/drivers/hid/hid-lg2ff.c
index b3cd1507dda2..1a42eaa6ca02 100644
--- a/drivers/hid/hid-lg2ff.c
+++ b/drivers/hid/hid-lg2ff.c
@@ -64,26 +64,13 @@ int lg2ff_init(struct hid_device *hid)
         struct hid_report *report;
         struct hid_input *hidinput = list_entry(hid->inputs.next,
                                                 struct hid_input, list);
-        struct list_head *report_list =
-                        &hid->report_enum[HID_OUTPUT_REPORT].report_list;
         struct input_dev *dev = hidinput->input;
         int error;
 
-        if (list_empty(report_list)) {
-                hid_err(hid, "no output report found\n");
+        /* Check that the report looks ok */
+        report = hid_validate_values(hid, HID_OUTPUT_REPORT, 0, 0, 7);
+        if (!report)
                 return -ENODEV;
-        }
-
-        report = list_entry(report_list->next, struct hid_report, list);
-
-        if (report->maxfield < 1) {
-                hid_err(hid, "output report is empty\n");
-                return -ENODEV;
-        }
-        if (report->field[0]->report_count < 7) {
-                hid_err(hid, "not enough values in the field\n");
-                return -ENODEV;
-        }
 
         lg2ff = kmalloc(sizeof(struct lg2ff_device), GFP_KERNEL);
         if (!lg2ff)