c318840fb2
The dummy-hcd driver was written under the assumption that all the parameters in URBs sent to its root hub would be valid. With URBs sent from userspace via usbfs, that assumption can be violated. In particular, the driver doesn't fully check the port-feature values stored in the wValue entry of Clear-Port-Feature and Set-Port-Feature requests. Values that are too large can cause the driver to perform an invalid left shift of more than 32 bits. Ironically, two of those left shifts are unnecessary, because they implement Set-Port-Feature requests that hubs are not required to support, according to section 11.24.2.13 of the USB-2.0 spec. This patch adds the appropriate checks for the port feature selector values and removes the unnecessary feature settings. It also rejects requests to set the TEST feature or to set or clear the INDICATOR and C_OVERCURRENT features, as none of these are relevant to dummy-hcd's root-hub emulation. CC: <stable@vger.kernel.org> Reported-and-tested-by: syzbot+5925509f78293baa7331@syzkaller.appspotmail.com Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Link: https://lore.kernel.org/r/20201230162044.GA727759@rowland.harvard.edu 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.