| From 67f7b2781fafcc0f52464880154b320fea1ae982 Mon Sep 17 00:00:00 2001 |
| From: Johan Hovold <johan@kernel.org> |
| Date: Mon, 30 Oct 2017 11:35:25 +0100 |
| Subject: spi: fix use-after-free at controller deregistration |
| |
| From: Johan Hovold <johan@kernel.org> |
| |
| commit 67f7b2781fafcc0f52464880154b320fea1ae982 upstream. |
| |
| The controller is typically freed as part of device_unregister() so |
| store the bus id before deregistration to avoid use-after-free when the |
| id is later released. |
| |
| Fixes: 9b61e302210e ("spi: Pick spi bus number from Linux idr or spi alias") |
| Signed-off-by: Johan Hovold <johan@kernel.org> |
| Signed-off-by: Mark Brown <broonie@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/spi/spi.c | 5 +++-- |
| 1 file changed, 3 insertions(+), 2 deletions(-) |
| |
| --- a/drivers/spi/spi.c |
| +++ b/drivers/spi/spi.c |
| @@ -2245,11 +2245,12 @@ static int __unregister(struct device *d |
| void spi_unregister_controller(struct spi_controller *ctlr) |
| { |
| struct spi_controller *found; |
| + int id = ctlr->bus_num; |
| int dummy; |
| |
| /* First make sure that this controller was ever added */ |
| mutex_lock(&board_lock); |
| - found = idr_find(&spi_master_idr, ctlr->bus_num); |
| + found = idr_find(&spi_master_idr, id); |
| mutex_unlock(&board_lock); |
| if (found != ctlr) { |
| dev_dbg(&ctlr->dev, |
| @@ -2269,7 +2270,7 @@ void spi_unregister_controller(struct sp |
| device_unregister(&ctlr->dev); |
| /* free bus id */ |
| mutex_lock(&board_lock); |
| - idr_remove(&spi_master_idr, ctlr->bus_num); |
| + idr_remove(&spi_master_idr, id); |
| mutex_unlock(&board_lock); |
| } |
| EXPORT_SYMBOL_GPL(spi_unregister_controller); |
