[PATCH 0/2] fix possible memory leak and use-after-free in __uio_register_device

[PATCH 0/2] fix possible memory leak and use-after-free in __uio_register_device

[Liu Jian]

fix possible memory leak and use-after-free in __uio_register_device

liujian (2):
  driver: uio: fix possible memory leak in __uio_register_device
  driver: uio: fix possible use-after-free in __uio_register_device

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

-- 
2.7.4

[PATCH 1/2] driver: uio: fix possible memory leak in __uio_register_device

[Liu Jian]

From: liujian <liujian56@huawei.com>

'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.

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>
---
 drivers/uio/uio.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 1313422..7280552 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -940,8 +940,10 @@ 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;
+	}
 
 	idev->dev.devt = MKDEV(uio_major, idev->minor);
 	idev->dev.class = &uio_class;
-- 
2.7.4

[PATCH 2/2] driver: uio: fix possible use-after-free in __uio_register_device

[Liu Jian]

From: liujian <liujian56@huawei.com>

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>
---
 drivers/uio/uio.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 7280552..be2a943 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);
-- 
2.7.4

Re: [PATCH 1/2] driver: uio: fix possible memory leak in __uio_register_device

[Greg KH]

On Tue, Jan 08, 2019 at 09:01:47PM +0800, Liu Jian wrote:
> From: liujian <liujian56@huawei.com>

This From: line does not match your email From: line, nor your
signed-off-by name :(

Please fix up and resend.

thanks,

greg k-h

Re: [PATCH 2/2] driver: uio: fix possible use-after-free in __uio_register_device

[Greg KH]

On Tue, Jan 08, 2019 at 09:01:48PM +0800, Liu Jian wrote:
> From: liujian <liujian56@huawei.com>

Same problem here.