From 7652dd2c5cb7b656471cc801d619fe24120643a3 Mon Sep 17 00:00:00 2001 From: Alan Stern <stern@rowland.harvard.edu> Date: Wed, 26 May 2021 11:32:44 -0400 Subject: USB: core: Check buffer length matches wLength for control transfers A type of inconsistency that can show up in control URBs is when the setup packet's wLength value does not match the URB's transfer_buffer_length field. The two should always be equal; differences could lead to information leaks or undefined behavior for OUT transfers or overruns for IN transfers. This patch adds a test for such mismatches during URB submission. If the test fails, the submission is rejected with a -EBADR error code (which is not used elsewhere in the USB core), and a debugging message is logged for people interested in tracking down these errors. Reviewed-by: Johan Hovold <johan@kernel.org> Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Link: https://lore.kernel.org/r/20210526153244.GA1400430@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- Documentation/driver-api/usb/error-codes.rst | 3 +++ 1 file changed, 3 insertions(+) (limited to 'Documentation/driver-api') diff --git a/Documentation/driver-api/usb/error-codes.rst b/Documentation/driver-api/usb/error-codes.rst index a3e84bfac776..8f9790c2d6f8 100644 --- a/Documentation/driver-api/usb/error-codes.rst +++ b/Documentation/driver-api/usb/error-codes.rst @@ -61,6 +61,9 @@ USB-specific: (c) requested data transfer length is invalid: negative or too large for the host controller. +``-EBADR`` The wLength value in a control URB's setup packet does + not match the URB's transfer_buffer_length. + ``-ENOSPC`` This request would overcommit the usb bandwidth reserved for periodic transfers (interrupt, isochronous). -- cgit v1.2.3