driver: uio: fix possible use-after-free in __uio_register_device

In uio_dev_add_attributes() error handing case, idev is used after
device_unregister(), in which 'idev' has been released, touch idev cause
use-after-free.

Fixes: a93e7b331568 ("uio: Prevent device destruction while fds are open")
Signed-off-by: Liu Jian <liujian56@huawei.com>
Reviewed-by: Hamish Martin <hamish.martin@alliedtelesis.co.nz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index f23ef23..a576989 100644 (file)
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -945,6 +945,7 @@ int __uio_register_device(struct module *owner,
                return ret;
        }
 
+       device_initialize(&idev->dev);
        idev->dev.devt = MKDEV(uio_major, idev->minor);
        idev->dev.class = &uio_class;
        idev->dev.parent = parent;
@@ -955,7 +956,7 @@ int __uio_register_device(struct module *owner,
        if (ret)
                goto err_device_create;
 
-       ret = device_register(&idev->dev);
+       ret = device_add(&idev->dev);
        if (ret)
                goto err_device_create;
 
@@ -987,9 +988,10 @@ int __uio_register_device(struct module *owner,
 err_request_irq:
        uio_dev_del_attributes(idev);
 err_uio_dev_add_attributes:
-       device_unregister(&idev->dev);
+       device_del(&idev->dev);
 err_device_create:
        uio_free_minor(idev);
+       put_device(&idev->dev);
        return ret;
 }
 EXPORT_SYMBOL_GPL(__uio_register_device);