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    Subject[PATCH 5.4 209/453] media: saa7146: fix array overflow in vidioc_s_audio()
    Date
    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 e6a71c17566d2..952ea250feda0 100644
    --- a/drivers/media/pci/saa7146/mxb.c
    +++ b/drivers/media/pci/saa7146/mxb.c
    @@ -641,16 +641,17 @@ 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


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