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Subject[PATCH v2] driver: uio: fix possible memory leak and use-after-free in __uio_register_device
Date
'idev' is malloced in __uio_register_device() and leak free it before
leaving from the uio_get_minor() error handing case, it will cause
memory leak.

Also, 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")
Fixes: e6789cd3dfb5 ("uio: Simplify uio error path by using devres
functions")
Signed-off-by: liujian <liujian56@huawei.com>
---
v1->v2:
change git log and fix code

drivers/uio/uio.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 1313422..be2a943 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -940,9 +940,12 @@ int __uio_register_device(struct module *owner,
atomic_set(&idev->event, 0);

ret = uio_get_minor(idev);
- if (ret)
+ if (ret) {
+ kfree(idev);
return ret;
+ }

+ device_initialize(&idev->dev);
idev->dev.devt = MKDEV(uio_major, idev->minor);
idev->dev.class = &uio_class;
idev->dev.parent = parent;
@@ -953,7 +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;

@@ -985,9 +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);
--
2.7.4
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