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usb: gadget: f_fs: Fix use-after-free

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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: 2e4c7553cd ("usb: gadget: f_fs: add aio support")
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
This commit is contained in:
Lars-Peter Clausen 2016-04-14 17:01:17 +02:00 committed by Felipe Balbi
parent 9772b47a4c
commit 38740a5b87
1 changed files with 2 additions and 3 deletions
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5
drivers/usb/gadget/function/f_fs.c
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@ -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);