From: Sriharsha Allenki <sallenki@xxxxxxxxxxxxxx>
commit f63ec55ff904b2f2e126884fcad93175f16ab4bb upstream.
In AIO case, the request is freed up if ep_queue fails.
However, io_data->req still has the reference to this freed
request. In the case of this failure if there is aio_cancel
call on this io_data it will lead to an invalid dequeue
operation and a potential use after free issue.
Fix this by setting the io_data->req to NULL when the request
is freed as part of queue failure.
Fixes: 2e4c7553cd6f ("usb: gadget: f_fs: add aio support")
Signed-off-by: Sriharsha Allenki <sallenki@xxxxxxxxxxxxxx>
CC: stable <stable@xxxxxxxxxxxxxxx>
Reviewed-by: Peter Chen <peter.chen@xxxxxxx>
Link: https://lore.kernel.org/r/20200326115620.12571-1-sallenki@xxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/gadget/function/f_fs.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1036,6 +1036,7 @@ static ssize_t ffs_epfile_io(struct file
ret = usb_ep_queue(ep->ep, req, GFP_ATOMIC);
if (unlikely(ret)) {
+ io_data->req = NULL;
usb_ep_free_request(ep->ep, req);
goto error_lock;
}
