From: Hans Verkuil hverkuil-cisco@xs4all.nl
commit 5eef2141776da02772c44ec406d6871a790761ee upstream.
Sanity checks were added to verify the v4l2_bt_timings blanking fields in order to avoid integer overflows when userspace passes weird values.
But that assumed that userspace would correctly fill in the front porch, backporch and sync values, but sometimes all you know is the total blanking, which is then assigned to just one of these fields.
And that can fail with these checks.
So instead set a maximum for the total horizontal and vertical blanking and check that each field remains below that.
That is still sufficient to avoid integer overflows, but it also allows for more flexibility in how userspace fills in these fields.
Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Fixes: 4b6d66a45ed3 ("media: v4l2-dv-timings: add sanity checks for blanking values") Signed-off-by: Mauro Carvalho Chehab mchehab@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/media/v4l2-core/v4l2-dv-timings.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-)
--- a/drivers/media/v4l2-core/v4l2-dv-timings.c +++ b/drivers/media/v4l2-core/v4l2-dv-timings.c @@ -145,6 +145,8 @@ bool v4l2_valid_dv_timings(const struct const struct v4l2_bt_timings *bt = &t->bt; const struct v4l2_bt_timings_cap *cap = &dvcap->bt; u32 caps = cap->capabilities; + const u32 max_vert = 10240; + u32 max_hor = 3 * bt->width;
if (t->type != V4L2_DV_BT_656_1120) return false; @@ -166,14 +168,20 @@ bool v4l2_valid_dv_timings(const struct if (!bt->interlaced && (bt->il_vbackporch || bt->il_vsync || bt->il_vfrontporch)) return false; - if (bt->hfrontporch > 2 * bt->width || - bt->hsync > 1024 || bt->hbackporch > 1024) + /* + * Some video receivers cannot properly separate the frontporch, + * backporch and sync values, and instead they only have the total + * blanking. That can be assigned to any of these three fields. + * So just check that none of these are way out of range. + */ + if (bt->hfrontporch > max_hor || + bt->hsync > max_hor || bt->hbackporch > max_hor) return false; - if (bt->vfrontporch > 4096 || - bt->vsync > 128 || bt->vbackporch > 4096) + if (bt->vfrontporch > max_vert || + bt->vsync > max_vert || bt->vbackporch > max_vert) return false; - if (bt->interlaced && (bt->il_vfrontporch > 4096 || - bt->il_vsync > 128 || bt->il_vbackporch > 4096)) + if (bt->interlaced && (bt->il_vfrontporch > max_vert || + bt->il_vsync > max_vert || bt->il_vbackporch > max_vert)) return false; return fnc == NULL || fnc(t, fnc_handle); }