Add a sanity check on the device id-table driver_info field to make sure
we never access a type structure (and function pointers) outside of the
device info array (e.g. if someone fails to ifdef a device-id entry).
Note that this also suppresses a compiler warning with -Warray-bounds
(gcc-11.3.0) when compile-testing the driver without enabling any of
the device type Kconfig options:
drivers/input/touchscreen/usbtouchscreen.c: In function 'usbtouch_probe':
drivers/input/touchscreen/usbtouchscreen.c:1668:16:warning: array subscript <unknown> is outside array bounds of 'struct usbtouch_device_info[0]' [-Warray-bounds]
1668 | type = &usbtouch_dev_info[id->driver_info];
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
Changes in v2
- use ARRAY_SIZE() for the sanity check (Dmitry)
- drop the dummy entry and combine the two patches as the sanity check
itself is enough to suppress the compiler warning (Dmitry)
- use -ENODEV instead of -EINVAL even if this means no error will be
logged in the unlikely event of a future driver bug
drivers/input/touchscreen/usbtouchscreen.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/input/touchscreen/usbtouchscreen.c b/drivers/input/touchscreen/usbtouchscreen.c
index 43c521f50c85..b01d026588c8 100644
--- a/drivers/input/touchscreen/usbtouchscreen.c
+++ b/drivers/input/touchscreen/usbtouchscreen.c
@@ -1654,6 +1654,9 @@ static int usbtouch_probe(struct usb_interface *intf,
if (id->driver_info == DEVTYPE_IGNORE)
return -ENODEV;
+ if (id->driver_info >= ARRAY_SIZE(usbtouch_dev_info))
+ return -ENODEV;
+
endpoint = usbtouch_get_input_endpoint(intf->cur_altsetting);
if (!endpoint)
return -ENXIO;
--
2.35.1
