From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars-Peter Clausen , Felipe Balbi Subject: [PATCH 4.5 022/200] usb: gadget: f_fs: Fix use-after-free Date: Mon, 2 May 2016 17:10:21 -0700 Message-Id: <20160503000555.353697555@linuxfoundation.org> In-Reply-To: <20160503000554.631204776@linuxfoundation.org> References: <20160503000554.631204776@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lars-Peter Clausen commit 38740a5b87d53ceb89eb2c970150f6e94e00373a upstream. When using asynchronous read or write operations on the USB endpoints the issuer of the IO request is notified by calling the ki_complete() callback of the submitted kiocb when the URB has been completed. Calling this ki_complete() callback will free kiocb. Make sure that the structure is no longer accessed beyond that point, otherwise undefined behaviour might occur. Fixes: 2e4c7553cd6f ("usb: gadget: f_fs: add aio support") Signed-off-by: Lars-Peter Clausen Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_fs.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -646,6 +646,7 @@ static void ffs_user_copy_worker(struct work); int ret = io_data->req->status ? io_data->req->status : io_data->req->actual; + bool kiocb_has_eventfd = io_data->kiocb->ki_flags & IOCB_EVENTFD; if (io_data->read && ret > 0) { use_mm(io_data->mm); @@ -657,13 +658,11 @@ static void ffs_user_copy_worker(struct io_data->kiocb->ki_complete(io_data->kiocb, ret, ret); - if (io_data->ffs->ffs_eventfd && - !(io_data->kiocb->ki_flags & IOCB_EVENTFD)) + if (io_data->ffs->ffs_eventfd && !kiocb_has_eventfd) eventfd_signal(io_data->ffs->ffs_eventfd, 1); usb_ep_free_request(io_data->ep, io_data->req); - io_data->kiocb->private = NULL; if (io_data->read) kfree(io_data->to_free); kfree(io_data->buf);