Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753208AbcDZSTH (ORCPT ); Tue, 26 Apr 2016 14:19:07 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:56514 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753186AbcDZSTE (ORCPT ); Tue, 26 Apr 2016 14:19:04 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Lars-Peter Clausen , Felipe Balbi , Kamal Mostafa Subject: [PATCH 4.2.y-ckt 66/93] usb: gadget: f_fs: Fix use-after-free Date: Tue, 26 Apr 2016 11:17:06 -0700 Message-Id: <1461694653-29506-67-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1461694653-29506-1-git-send-email-kamal@canonical.com> References: <1461694653-29506-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 4.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1958 Lines: 53 4.2.8-ckt9 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ 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: Kamal Mostafa --- drivers/usb/gadget/function/f_fs.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 6e7be91..82240db 100644 --- 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_struct *work) 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 work_struct *work) 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); -- 2.7.4