7c96edc6e7
commit 386e15a650447f53de3d2d8819ce9393f31650a4 upstream.
Sometimes the embedded controller firmware does not
terminate the list of alternate modes that the partner
supports in its response to the GET_ALTERNATE_MODES command.
Instead the firmware returns the supported alternate modes
over and over again until the driver stops requesting them.
If that happens, the number of modes for each alternate mode
will exceed the maximum 6 that is defined in the USB Power
Delivery specification. Making sure that can't happen by
adding a check for it.
This fixes NULL pointer dereference that is caused by the
overrun.
Fixes: ad74b8649beaf ("usb: typec: ucsi: Preliminary support for alternate modes")
Cc: stable@vger.kernel.org
Reported-by: Zwane Mwaikambo <zwanem@gmail.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20200916090034.25119-3-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.