From: Sean Tranchetti stranche@codeaurora.org
[ Upstream commit e7a86c687e64ab24f88330ad24ecc9442ce40c5a ]
During the exit/unregistration process of the RmNet driver, the function rmnet_unregister_real_device() is called to handle freeing the driver's internal state and removing the RX handler on the underlying physical device. However, the order of operations this function performs is wrong and can lead to a use after free of the rmnet_port structure.
Before calling netdev_rx_handler_unregister(), this port structure is freed with kfree(). If packets are received on any RmNet devices before synchronize_net() completes, they will attempt to use this already-freed port structure when processing the packet. As such, before cleaning up any other internal state, the RX handler must be unregistered in order to guarantee that no further packets will arrive on the device.
Fixes: ceed73a2cf4a ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation") Signed-off-by: Sean Tranchetti stranche@codeaurora.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c @@ -66,10 +66,10 @@ static int rmnet_unregister_real_device( if (port->nr_rmnet_devs) return -EINVAL;
- kfree(port); - netdev_rx_handler_unregister(real_dev);
+ kfree(port); + /* release reference on real_dev */ dev_put(real_dev);