diff options
| author | sumitg | 2019-05-17 09:53:42 -0400 |
|---|---|---|
| committer | Mauro Carvalho Chehab | 2019-05-28 12:50:33 -0400 |
| commit | 3e0f724346e96daae7792262c6767449795ac3b5 (patch) | |
| tree | 128521a788727c8e4382a361e974a52dd74abca9 | |
| parent | 0c310868826eb10b724a21dcd05e19768b6fc3a8 (diff) | |
media: v4l2-core: fix use-after-free error
Fixing use-after-free within __v4l2_ctrl_handler_setup().
Memory is being freed with kfree(new_ref) for duplicate
control reference entry but ctrl->cluster pointer is still
referring to freed duplicate entry resulting in error on
access. Change done to update cluster pointer only when new
control reference is added.
==================================================================
BUG: KASAN: use-after-free in __v4l2_ctrl_handler_setup+0x388/0x428
Read of size 8 at addr ffffffc324e78618 by task systemd-udevd/312
Allocated by task 312:
Freed by task 312:
The buggy address belongs to the object at ffffffc324e78600
which belongs to the cache kmalloc-64 of size 64
The buggy address is located 24 bytes inside of
64-byte region [ffffffc324e78600, ffffffc324e78640)
The buggy address belongs to the page:
page:ffffffbf0c939e00 count:1 mapcount:0 mapping:
(null) index:0xffffffc324e78f80
flags: 0x4000000000000100(slab)
raw: 4000000000000100 0000000000000000 ffffffc324e78f80 000000018020001a
raw: 0000000000000000 0000000100000001 ffffffc37040fb80 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffffffc324e78500: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffffffc324e78580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffffffc324e78600: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
^
ffffffc324e78680: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
ffffffc324e78700: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
==================================================================
Suggested-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
| -rw-r--r-- | drivers/media/v4l2-core/v4l2-ctrls.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c index f53d4da3d1c9..2ffffd923265 100644 --- a/drivers/media/v4l2-core/v4l2-ctrls.c +++ b/drivers/media/v4l2-core/v4l2-ctrls.c @@ -2180,15 +2180,6 @@ static int handler_new_ref(struct v4l2_ctrl_handler *hdl, if (size_extra_req) new_ref->p_req.p = &new_ref[1]; - if (ctrl->handler == hdl) { - /* By default each control starts in a cluster of its own. - new_ref->ctrl is basically a cluster array with one - element, so that's perfect to use as the cluster pointer. - But only do this for the handler that owns the control. */ - ctrl->cluster = &new_ref->ctrl; - ctrl->ncontrols = 1; - } - INIT_LIST_HEAD(&new_ref->node); mutex_lock(hdl->lock); @@ -2221,6 +2212,15 @@ insert_in_hash: hdl->buckets[bucket] = new_ref; if (ctrl_ref) *ctrl_ref = new_ref; + if (ctrl->handler == hdl) { + /* By default each control starts in a cluster of its own. + * new_ref->ctrl is basically a cluster array with one + * element, so that's perfect to use as the cluster pointer. + * But only do this for the handler that owns the control. + */ + ctrl->cluster = &new_ref->ctrl; + ctrl->ncontrols = 1; + } unlock: mutex_unlock(hdl->lock); |