summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorKim Woelders <kim@woelders.dk>2016-04-03 19:40:25 +0200
committerKim Woelders <kim@woelders.dk>2016-04-07 20:20:47 +0200
commit37a96801663b7b4cd3fbe56cc0eb8b6a17e766a8 (patch)
tree357923ea085dbf295aa2dd1bc38ee13860181ae8
parentRevert "gif: fix oob reads w/bad colormaps" (diff)
downloadimlib2-37a96801663b7b4cd3fbe56cc0eb8b6a17e766a8.tar.gz
GIF loader: Fix out-of-bound reads from colormap.
Bug-Debian: http://bugs.debian.org/785369 Note: removes all special-casing from the inner loop, optimize for common case. Author: Yuriy M. Kaminskiy <yumkam+debian@gmail.com> Reported-By: Jakub Wilk <jwilk@debian.org> Thanks to Bernhard U:belacker <bernhardu@vr-web.de> for analysis.
-rw-r--r--src/modules/loaders/loader_gif.c31
1 files changed, 17 insertions, 14 deletions
diff --git a/src/modules/loaders/loader_gif.c b/src/modules/loaders/loader_gif.c
index 638df59..4f08d64 100644
--- a/src/modules/loaders/loader_gif.c
+++ b/src/modules/loaders/loader_gif.c
@@ -141,8 +141,24 @@ load(ImlibImage * im, ImlibProgressFunction progress, char progress_granularity,
if (im->loader || immediate_load || progress)
{
+ DATA32 colormap[256];
+
bg = gif->SBackGroundColor;
cmap = (gif->Image.ColorMap ? gif->Image.ColorMap : gif->SColorMap);
+ memset (colormap, 0, sizeof(colormap));
+ if (cmap != NULL)
+ {
+ for (i = cmap->ColorCount > 256 ? 256 : cmap->ColorCount; i-- > 0;)
+ {
+ r = cmap->Colors[i].Red;
+ g = cmap->Colors[i].Green;
+ b = cmap->Colors[i].Blue;
+ colormap[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
+ }
+ /* if bg > cmap->ColorCount, it is transparent black already */
+ if (transp >= 0 && transp < 256)
+ colormap[transp] = bg >= 0 && bg < 256 ? colormap[bg] & 0x00ffffff : 0x00000000;
+ }
im->data = (DATA32 *) malloc(sizeof(DATA32) * w * h);
if (!im->data)
goto quit;
@@ -161,20 +177,7 @@ load(ImlibImage * im, ImlibProgressFunction progress, char progress_granularity,
{
for (j = 0; j < w; j++)
{
- if (rows[i][j] == transp)
- {
- r = cmap->Colors[bg].Red;
- g = cmap->Colors[bg].Green;
- b = cmap->Colors[bg].Blue;
- *ptr++ = 0x00ffffff & ((r << 16) | (g << 8) | b);
- }
- else
- {
- r = cmap->Colors[rows[i][j]].Red;
- g = cmap->Colors[rows[i][j]].Green;
- b = cmap->Colors[rows[i][j]].Blue;
- *ptr++ = (0xff << 24) | (r << 16) | (g << 8) | b;
- }
+ *ptr++ = colormap[rows[i][j]];
per += per_inc;
if (progress && (((int)per) != last_per)
&& (((int)per) % progress_granularity == 0))