From: Liu Jian <liujian56@huawei.com>
Date: Tue, 22 Jan 2019 22:45:38 +0000 (+0800)
Subject: driver: uio: fix possible use-after-free in __uio_register_device
X-Git-Tag: v5.4-rc1~1512^2~97
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=221a1f4ac12d2ab46246c160b2e00d1b1160d5d9;p=platform%2Fkernel%2Flinux-rpi.git

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
--- 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);