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| author | sumitg <sumitg@nvidia.com> | 2019-05-17 09:53:42 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-07-26 09:10:17 +0200 |
| commit | bb50e4a36b33427fc8f066c227b641abca9452a9 (patch) | |
| tree | d59bd5c5f88347ce56683fb7e0f6b169ebbc594e /drivers/media | |
| parent | a1b01aeb1d1e5470f906809df67b71acfee78de6 (diff) | |
| download | linux-stable-bb50e4a36b33427fc8f066c227b641abca9452a9.tar.gz linux-stable-bb50e4a36b33427fc8f066c227b641abca9452a9.tar.bz2 linux-stable-bb50e4a36b33427fc8f066c227b641abca9452a9.zip | |
media: v4l2-core: fix use-after-free error
[ Upstream commit 3e0f724346e96daae7792262c6767449795ac3b5 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/media')
| -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 7d3a33258748..3c720f54efa8 100644 --- a/drivers/media/v4l2-core/v4l2-ctrls.c +++ b/drivers/media/v4l2-core/v4l2-ctrls.c @@ -2149,15 +2149,6 @@ 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); @@ -2190,6 +2181,15 @@ 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); |