From: Ilya Dryomov idryomov@gmail.com
commit f7c4d9b133c7a04ca619355574e96b6abf209fba upstream.
If getting an ID or setting up a work queue in rbd_dev_create() fails, use-after-free on rbd_dev->rbd_client, rbd_dev->spec and rbd_dev->opts is triggered in do_rbd_add(). The root cause is that the ownership of these structures is transfered to rbd_dev prematurely and they all end up getting freed when rbd_dev_create() calls rbd_dev_free() prior to returning to do_rbd_add().
Found by Linux Verification Center (linuxtesting.org) with SVACE, an incomplete patch submitted by Natalia Petrova n.petrova@fintech.ru.
Cc: stable@vger.kernel.org Fixes: 1643dfa4c2c8 ("rbd: introduce a per-device ordered workqueue") Signed-off-by: Ilya Dryomov idryomov@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/block/rbd.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-)
--- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -5292,8 +5292,7 @@ static void rbd_dev_release(struct devic module_put(THIS_MODULE); }
-static struct rbd_device *__rbd_dev_create(struct rbd_client *rbdc, - struct rbd_spec *spec) +static struct rbd_device *__rbd_dev_create(struct rbd_spec *spec) { struct rbd_device *rbd_dev;
@@ -5338,9 +5337,6 @@ static struct rbd_device *__rbd_dev_crea rbd_dev->dev.parent = &rbd_root_dev; device_initialize(&rbd_dev->dev);
- rbd_dev->rbd_client = rbdc; - rbd_dev->spec = spec; - return rbd_dev; }
@@ -5353,12 +5349,10 @@ static struct rbd_device *rbd_dev_create { struct rbd_device *rbd_dev;
- rbd_dev = __rbd_dev_create(rbdc, spec); + rbd_dev = __rbd_dev_create(spec); if (!rbd_dev) return NULL;
- rbd_dev->opts = opts; - /* get an id and fill in device name */ rbd_dev->dev_id = ida_simple_get(&rbd_dev_id_ida, 0, minor_to_rbd_dev_id(1 << MINORBITS), @@ -5375,6 +5369,10 @@ static struct rbd_device *rbd_dev_create /* we have a ref from do_rbd_add() */ __module_get(THIS_MODULE);
+ rbd_dev->rbd_client = rbdc; + rbd_dev->spec = spec; + rbd_dev->opts = opts; + dout("%s rbd_dev %p dev_id %d\n", __func__, rbd_dev, rbd_dev->dev_id); return rbd_dev;
@@ -6736,7 +6734,7 @@ static int rbd_dev_probe_parent(struct r goto out_err; }
- parent = __rbd_dev_create(rbd_dev->rbd_client, rbd_dev->parent_spec); + parent = __rbd_dev_create(rbd_dev->parent_spec); if (!parent) { ret = -ENOMEM; goto out_err; @@ -6746,8 +6744,8 @@ static int rbd_dev_probe_parent(struct r * Images related by parent/child relationships always share * rbd_client and spec/parent_spec, so bump their refcounts. */ - __rbd_get_client(rbd_dev->rbd_client); - rbd_spec_get(rbd_dev->parent_spec); + parent->rbd_client = __rbd_get_client(rbd_dev->rbd_client); + parent->spec = rbd_spec_get(rbd_dev->parent_spec);
__set_bit(RBD_DEV_FLAG_READONLY, &parent->flags);