This is a note to let you know that I've just added the patch titled
nbd: fix uaf in nbd_open
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nbd-fix-uaf-in-nbd_open.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9bfd87e640f47cc5f94621ccce8174f9451c39e5
Author: Li Lingfeng <lilingfeng3@xxxxxxxxxx>
Date: Tue Nov 7 18:34:35 2023 +0800
nbd: fix uaf in nbd_open
[ Upstream commit 327462725b0f759f093788dfbcb2f1fd132f956b ]
Commit 4af5f2e03013 ("nbd: use blk_mq_alloc_disk and
blk_cleanup_disk") cleans up disk by blk_cleanup_disk() and it won't set
disk->private_data as NULL as before. UAF may be triggered in nbd_open()
if someone tries to open nbd device right after nbd_put() since nbd has
been free in nbd_dev_remove().
Fix this by implementing ->free_disk and free private data in it.
Fixes: 4af5f2e03013 ("nbd: use blk_mq_alloc_disk and blk_cleanup_disk")
Signed-off-by: Li Lingfeng <lilingfeng3@xxxxxxxxxx>
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20231107103435.2074904-1-lilingfeng@xxxxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 800f131222fc8..855fdf5c3b4ea 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -250,7 +250,6 @@ static void nbd_dev_remove(struct nbd_device *nbd)
struct gendisk *disk = nbd->disk;
del_gendisk(disk);
- put_disk(disk);
blk_mq_free_tag_set(&nbd->tag_set);
/*
@@ -261,7 +260,7 @@ static void nbd_dev_remove(struct nbd_device *nbd)
idr_remove(&nbd_index_idr, nbd->index);
mutex_unlock(&nbd_index_mutex);
destroy_workqueue(nbd->recv_workq);
- kfree(nbd);
+ put_disk(disk);
}
static void nbd_dev_remove_work(struct work_struct *work)
@@ -1608,6 +1607,13 @@ static void nbd_release(struct gendisk *disk)
nbd_put(nbd);
}
+static void nbd_free_disk(struct gendisk *disk)
+{
+ struct nbd_device *nbd = disk->private_data;
+
+ kfree(nbd);
+}
+
static const struct block_device_operations nbd_fops =
{
.owner = THIS_MODULE,
@@ -1615,6 +1621,7 @@ static const struct block_device_operations nbd_fops =
.release = nbd_release,
.ioctl = nbd_ioctl,
.compat_ioctl = nbd_ioctl,
+ .free_disk = nbd_free_disk,
};
#if IS_ENABLED(CONFIG_DEBUG_FS)
