diff options
| author | Guanghui Feng <[email protected]> | 2023-12-21 17:57:43 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <[email protected]> | 2024-01-25 14:52:31 -0800 |
| commit | 5cf604ee538ed0c467abe3b4cda5308a6398f0f7 (patch) | |
| tree | beab210545b0cef2221ff2a028da46cc5c2d31d9 | |
| parent | 659be220e6925b42247312cad858849cf032d325 (diff) | |
| download | linux-5cf604ee538ed0c467abe3b4cda5308a6398f0f7.tar.gz | |
uio: Fix use-after-free in uio_open
commit 0c9ae0b8605078eafc3bea053cc78791e97ba2e2 upstream.
core-1 core-2
-------------------------------------------------------
uio_unregister_device uio_open
idev = idr_find()
device_unregister(&idev->dev)
put_device(&idev->dev)
uio_device_release
get_device(&idev->dev)
kfree(idev)
uio_free_minor(minor)
uio_release
put_device(&idev->dev)
kfree(idev)
-------------------------------------------------------
In the core-1 uio_unregister_device(), the device_unregister will kfree
idev when the idev->dev kobject ref is 1. But after core-1
device_unregister, put_device and before doing kfree, the core-2 may
get_device. Then:
1. After core-1 kfree idev, the core-2 will do use-after-free for idev.
2. When core-2 do uio_release and put_device, the idev will be double
freed.
To address this issue, we can get idev atomic & inc idev reference with
minor_lock.
Fixes: 57c5f4df0a5a ("uio: fix crash after the device is unregistered")
Cc: stable <[email protected]>
Signed-off-by: Guanghui Feng <[email protected]>
Reviewed-by: Baolin Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
| -rw-r--r-- | drivers/uio/uio.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c index ea96e319c8a0ef..e9b739def70e35 100644 --- a/drivers/uio/uio.c +++ b/drivers/uio/uio.c @@ -464,13 +464,13 @@ static int uio_open(struct inode *inode, struct file *filep) mutex_lock(&minor_lock); idev = idr_find(&uio_idr, iminor(inode)); - mutex_unlock(&minor_lock); if (!idev) { ret = -ENODEV; + mutex_unlock(&minor_lock); goto out; } - get_device(&idev->dev); + mutex_unlock(&minor_lock); if (!try_module_get(idev->owner)) { ret = -ENODEV; @@ -1062,9 +1062,8 @@ void uio_unregister_device(struct uio_info *info) wake_up_interruptible(&idev->wait); kill_fasync(&idev->async_queue, SIGIO, POLL_HUP); - device_unregister(&idev->dev); - uio_free_minor(minor); + device_unregister(&idev->dev); return; } |