From 38740a5b87d53ceb89eb2c970150f6e94e00373a Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Thu, 14 Apr 2016 17:01:17 +0200 Subject: [PATCH] usb: gadget: f_fs: Fix use-after-free 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") Cc: # v3.15+ Signed-off-by: Lars-Peter Clausen Signed-off-by: Felipe Balbi --- 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 e21ca2bd..15b648c 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