[media] sh_vou: avoid going past arrays

Smatch reports two issues:
	drivers/media/platform/sh_vou.c:670 vou_adjust_output() error: buffer overflow 'vou_scale_v_num' 3 <= 4
	drivers/media/platform/sh_vou.c:670 vou_adjust_output() error: buffer overflow 'vou_scale_v_den' 3 <= 4

It seems that there's actually a bug here: the same var (idx) is used
as an index for vertical and horizontal scaling arrays. However,
there are 4 elements on the h arrays, and only 3 at the v ones.

On the first loop, it may select index 4 for the horizontal array.

In this case, if the second loop fails to select an index, the
code would keep using 4 for the vertical array, with is past of
the array sizes.

The intent here seems to use index 0, if the scale is not found.

So, use a separate var for the vertical index.

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/platform/sh_vou.c b/drivers/media/platform/sh_vou.c
index 829e85c26610ec896239ce1d9ce9017dd870ad8c..8b799bae01b8dfed157fb5f73429e9c3d60ae9bd 100644 (file)
--- a/drivers/media/platform/sh_vou.c
+++ b/drivers/media/platform/sh_vou.c
@@ -600,7 +600,7 @@ static void vou_adjust_output(struct sh_vou_geometry *geo, v4l2_std_id std)
 {
        unsigned int best_err = UINT_MAX, best = geo->in_width,
                width_max, height_max, img_height_max;
-       int i, idx = 0;
+       int i, idx_h = 0, idx_v = 0;
 
        if (std & V4L2_STD_525_60) {
                width_max = 858;
@@ -625,7 +625,7 @@ static void vou_adjust_output(struct sh_vou_geometry *geo, v4l2_std_id std)
                err = abs(found - geo->output.width);
                if (err < best_err) {
                        best_err = err;
-                       idx = i;
+                       idx_h = i;
                        best = found;
                }
                if (!err)
@@ -633,12 +633,12 @@ static void vou_adjust_output(struct sh_vou_geometry *geo, v4l2_std_id std)
        }
 
        geo->output.width = best;
-       geo->scale_idx_h = idx;
+       geo->scale_idx_h = idx_h;
        if (geo->output.left + best > width_max)
                geo->output.left = width_max - best;
 
        pr_debug("%s(): W %u * %u/%u = %u\n", __func__, geo->in_width,
-                vou_scale_h_num[idx], vou_scale_h_den[idx], best);
+                vou_scale_h_num[idx_h], vou_scale_h_den[idx_h], best);
 
        best_err = UINT_MAX;
 
@@ -655,7 +655,7 @@ static void vou_adjust_output(struct sh_vou_geometry *geo, v4l2_std_id std)
                err = abs(found - geo->output.height);
                if (err < best_err) {
                        best_err = err;
-                       idx = i;
+                       idx_v = i;
                        best = found;
                }
                if (!err)
@@ -663,12 +663,12 @@ static void vou_adjust_output(struct sh_vou_geometry *geo, v4l2_std_id std)
        }
 
        geo->output.height = best;
-       geo->scale_idx_v = idx;
+       geo->scale_idx_v = idx_v;
        if (geo->output.top + best > height_max)
                geo->output.top = height_max - best;
 
        pr_debug("%s(): H %u * %u/%u = %u\n", __func__, geo->in_height,
-                vou_scale_v_num[idx], vou_scale_v_den[idx], best);
+                vou_scale_v_num[idx_v], vou_scale_v_den[idx_v], best);
 }
 
 static int sh_vou_s_fmt_vid_out(struct file *file, void *priv,