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authorGuanghui Feng <guanghuifeng@linux.alibaba.com>2023-12-21 17:57:43 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-01-04 17:03:47 +0100
commit0c9ae0b8605078eafc3bea053cc78791e97ba2e2 (patch)
treec9b91096cecdf801ae8b8b0cd4bdcaf18023b299 /drivers/uio
parent97d62760e441af9ed393e127a46172f9534b5808 (diff)
uio: Fix use-after-free in uio_open
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 <stable@kernel.org> Signed-off-by: Guanghui Feng <guanghuifeng@linux.alibaba.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Link: https://lore.kernel.org/r/1703152663-59949-1-git-send-email-guanghuifeng@linux.alibaba.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/uio')
-rw-r--r--drivers/uio/uio.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 62082d64ece0..2d572f6c8ec8 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -466,13 +466,13 @@ 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;
@@ -1064,9 +1064,8 @@ 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;
}