[PATCH 4.4 063/132] media: saa7146: fix array overflow in vidioc_s_audio()

Greg Kroah-Hartman
2020-12-28T16:45:25Z

From: Dan Carpenter <dan.carpenter@oracle.com>

[ Upstream commit 8e4d86e241cf035d6d3467cd346e7ce490681937 ]

The "a->index" value comes from the user via the ioctl. The problem is
that the shift can wrap resulting in setting "mxb->cur_audinput" to an
invalid value, which later results in an array overflow.

Fixes: 6680427791c9 ("[media] mxb: fix audio handling")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/pci/saa7146/mxb.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/media/pci/saa7146/mxb.c b/drivers/media/pci/saa7146/mxb.c
index 0ca1e07ae7837..868af73c5536a 100644
--- a/drivers/media/pci/saa7146/mxb.c
+++ b/drivers/media/pci/saa7146/mxb.c
@@ -652,16 +652,17 @@ static int vidioc_s_audio(struct file *file, void *fh, const struct v4l2_audio *
struct mxb *mxb = (struct mxb *)dev->ext_priv;

DEB_D("VIDIOC_S_AUDIO %d\n", a->index);
- if (mxb_inputs[mxb->cur_input].audioset & (1 << a->index)) {
- if (mxb->cur_audinput != a->index) {
- mxb->cur_audinput = a->index;
- tea6420_route(mxb, a->index);
- if (mxb->cur_audinput == 0)
- mxb_update_audmode(mxb);
- }
- return 0;
+ if (a->index >= 32 ||
+ !(mxb_inputs[mxb->cur_input].audioset & (1 << a->index)))
+ return -EINVAL;
+
+ if (mxb->cur_audinput != a->index) {
+ mxb->cur_audinput = a->index;
+ tea6420_route(mxb, a->index);
+ if (mxb->cur_audinput == 0)
+ mxb_update_audmode(mxb);
}
- return -EINVAL;
+ return 0;
}

#ifdef CONFIG_VIDEO_ADV_DEBUG
--
2.27.0