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authorLars-Peter Clausen <lars@metafoo.de>2016-04-14 17:01:17 +0200
committerFelipe Balbi <felipe.balbi@linux.intel.com>2016-04-20 10:38:06 +0300
commit38740a5b87d53ceb89eb2c970150f6e94e00373a (patch)
tree3846402f09e425009ae20f6f0f58be4227291cab
parent9772b47a4c2916d645c551228b6085ea24acbe5d (diff)
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: <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>
-rw-r--r--drivers/usb/gadget/function/f_fs.c5
1 files 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);