[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-Id: <20191024164538.3161474-1-john@metanate.com>
Date: Thu, 24 Oct 2019 17:45:32 +0100
From: John Keeping <john@...anate.com>
To: linux-usb@...r.kernel.org
Cc: Felipe Balbi <balbi@...nel.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-kernel@...r.kernel.org, John Keeping <john@...anate.com>
Subject: [PATCH 0/6] USB: gadget: f_hid: fix lifetime issues
File descriptors referencing the /dev/hidgN device created by the HID
gadget can outlive the underlying gadget function, which creates easy to
trigger use-after-frees in the kernel.
A simple reproduction for this using the libusbgx example programs is:
$ gadget-hid
$ exec 3<> /dev/hidg0
$ gadget-vid-pid-remove
$ exec 3<&-
Closing the file descriptor on the last line triggers a use-after-free
which can be seen immediately with slub_debug=P.
This series fixes this by making the struct cdev associated with the
module rather than dynamically allocated for the gadget and changing
struct f_hidg to be refcounted instead of tied to the gadget lifetime.
John Keeping (6):
USB: gadget: f_hid: move chardev setup to module init
USB: gadget: f_hid: switch to IDR for tracking minors
USB: gadget: f_hid: find f_hidg by IDR lookup on open
USB: gadget: f_hid: decouple cdev from f_hidg lifetime
USB: gadget: f_hid: refcount f_hidg structure
USB: gadget: f_hid: return ENODEV from read/write after deletion
drivers/usb/gadget/function/f_hid.c | 141 +++++++++++++++++++---------
drivers/usb/gadget/function/u_hid.h | 3 -
2 files changed, 95 insertions(+), 49 deletions(-)
--
2.23.0
Powered by blists - more mailing lists