HID: logitech-dj: check report length

Malicious USB devices can send bogus reports smaller than the expected
buffer size. Ensure that the length is valid to avoid reading out of
bounds.

Signed-off-by: Peter Wu <peter@lekensteyn.nl>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index c917ab61aafa6156b433ed3148a31384ac6d4292..5bc6d80d5be79f465f3cbbb686c471db6162eb63 100644 (file)
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -962,10 +962,24 @@ static int logi_dj_raw_event(struct hid_device *hdev,
 
        switch (data[0]) {
        case REPORT_ID_DJ_SHORT:
+               if (size != DJREPORT_SHORT_LENGTH) {
+                       dev_err(&hdev->dev, "DJ report of bad size (%d)", size);
+                       return false;
+               }
                return logi_dj_dj_event(hdev, report, data, size);
        case REPORT_ID_HIDPP_SHORT:
-               /* intentional fallthrough */
+               if (size != HIDPP_REPORT_SHORT_LENGTH) {
+                       dev_err(&hdev->dev,
+                               "Short HID++ report of bad size (%d)", size);
+                       return false;
+               }
+               return logi_dj_hidpp_event(hdev, report, data, size);
        case REPORT_ID_HIDPP_LONG:
+               if (size != HIDPP_REPORT_LONG_LENGTH) {
+                       dev_err(&hdev->dev,
+                               "Long HID++ report of bad size (%d)", size);
+                       return false;
+               }
                return logi_dj_hidpp_event(hdev, report, data, size);
        }