[media] VIDIOC_ENUM_FREQ_BANDS fix

When VIDIOC_ENUM_FREQ_BANDS is called for a driver that doesn't supply an
enum_freq_bands op, then it will fall back to reporting a single freq band
based on information from g_tuner or g_modulator.

Due to a bug this is an infinite list since the index field wasn't tested.

This patch fixes this and returns -EINVAL if index != 0.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/media/video/v4l2-ioctl.c b/drivers/media/video/v4l2-ioctl.c
index c3b7b5f59b32..54f4ac612e8e 100644
--- a/drivers/media/video/v4l2-ioctl.c
+++ b/drivers/media/video/v4l2-ioctl.c
@@ -1853,6 +1853,8 @@ static int v4l_enum_freq_bands(const struct v4l2_ioctl_ops *ops,
                         .type = type,
                 };
 
+                if (p->index)
+                        return -EINVAL;
                 err = ops->vidioc_g_tuner(file, fh, &t);
                 if (err)
                         return err;
@@ -1870,6 +1872,8 @@ static int v4l_enum_freq_bands(const struct v4l2_ioctl_ops *ops,
 
                 if (type != V4L2_TUNER_RADIO)
                         return -EINVAL;
+                if (p->index)
+                        return -EINVAL;
                 err = ops->vidioc_g_modulator(file, fh, &m);
                 if (err)
                         return err;