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avfilter/paletteuse: remove unused alpha split dimension 

The equalities in the w{r,g,b} range checks make sure longest is never
0. Even if the alpha ended up being selected in get_next_color() it
would cause underread memory accesses in its caller (colormap_insert).
This commit is contained in:
Clément Bœsch 2022-11-05 01:00:09 +01:00
parent 71ed92e9c4
commit 4c061bc837
1 changed files with 16 additions and 17 deletions
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33
libavfilter/vf_paletteuse.c
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@ -211,7 +211,7 @@ static void colormap_nearest_node(const struct color_node *map,
struct nearest_color *nearest)
{
const struct color_node *kd = map + node_pos;
const int shift = (3 - kd->split) * 8;
const int shift = (2 - kd->split) * 8;
int dx, nearer_kd_id, further_kd_id;
const uint32_t current = kd->val;
const int current_to_target = diff(target, current, trans_thresh);
@ -270,7 +270,7 @@ static av_always_inline uint8_t colormap_nearest_iterative(const struct color_no
/* Check if it's not a leaf */
if (kd->left_id != -1 || kd->right_id != -1) {
const int shift = (3 - kd->split) * 8;
const int shift = (2 - kd->split) * 8;
const int dx = (target>>shift & 0xff) - (current>>shift & 0xff);
int nearer_kd_id, further_kd_id;
@ -497,7 +497,7 @@ static void disp_node(AVBPrint *buf,
const uint32_t fontcolor = (node->val>>16 & 0xff) > 0x50 &&
(node->val>> 8 & 0xff) > 0x50 &&
(node->val & 0xff) > 0x50 ? 0 : 0xffffff;
const int rgb_comp = node->split - 1;
const int rgb_comp = node->split;
av_bprintf(buf, "%*cnode%d ["
"label=\"%c%02X%c%02X%c%02X%c\" "
"fillcolor=\"#%06"PRIX32"\" "
@ -588,16 +588,15 @@ static int cmp_##name(const void *pa, const void *pb) \
{ \
const struct color *a = pa; \
const struct color *b = pb; \
return (int)(a->value >> (8 * (3 - (pos))) & 0xff) \
- (int)(b->value >> (8 * (3 - (pos))) & 0xff); \
return (int)(a->value >> (8 * (2 - (pos))) & 0xff) \
- (int)(b->value >> (8 * (2 - (pos))) & 0xff); \
}
DECLARE_CMP_FUNC(a, 0)
DECLARE_CMP_FUNC(r, 1)
DECLARE_CMP_FUNC(g, 2)
DECLARE_CMP_FUNC(b, 3)
DECLARE_CMP_FUNC(r, 0)
DECLARE_CMP_FUNC(g, 1)
DECLARE_CMP_FUNC(b, 2)
static const cmp_func cmp_funcs[] = {cmp_a, cmp_r, cmp_g, cmp_b};
static const cmp_func cmp_funcs[] = {cmp_r, cmp_g, cmp_b};
static int get_next_color(const uint8_t *color_used, const uint32_t *palette,
const int trans_thresh,
@ -650,9 +649,9 @@ static int get_next_color(const uint8_t *color_used, const uint32_t *palette,
wr = ranges.max[0] - ranges.min[0];
wg = ranges.max[1] - ranges.min[1];
wb = ranges.max[2] - ranges.min[2];
if (wr >= wg && wr >= wb) longest = 1;
if (wg >= wr && wg >= wb) longest = 2;
if (wb >= wr && wb >= wg) longest = 3;
if (wr >= wg && wr >= wb) longest = 0;
if (wg >= wr && wg >= wb) longest = 1;
if (wb >= wr && wb >= wg) longest = 2;
cmpf = cmp_funcs[longest];
*component = longest;
@ -692,13 +691,13 @@ static int colormap_insert(struct color_node *map,
/* get the two boxes this node creates */
box1 = box2 = *box;
comp_value = node->val >> ((3 - component) * 8) & 0xff;
box1.max[component-1] = comp_value;
box2.min[component-1] = FFMIN(comp_value + 1, 255);
comp_value = node->val >> ((2 - component) * 8) & 0xff;
box1.max[component] = comp_value;
box2.min[component] = FFMIN(comp_value + 1, 255);
node_left_id = colormap_insert(map, color_used, nb_used, palette, trans_thresh, &box1);
if (box2.min[component-1] <= box2.max[component-1])
if (box2.min[component] <= box2.max[component])
node_right_id = colormap_insert(map, color_used, nb_used, palette, trans_thresh, &box2);
node->left_id = node_left_id;