Avoid overflow in calculateNumTiles when size=MAX_INT (AcademySoftwar…

…eFoundation#825) * Avoid overflow in calculateNumTiles when size=MAX_INT Signed-off-by: Cary Phillips <[email protected]> * Compute level size with 64 bits to avoid overflow Signed-off-by: Cary Phillips <[email protected]>
cary-ilm · May 12, 2021 · 28ac26b · 28ac26b
1 parent ff65d03
commit 28ac26b
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/OpenEXR/IlmImf/ImfTiledMisc.cpp b/OpenEXR/IlmImf/ImfTiledMisc.cpp
@@ -301,7 +301,9 @@ calculateNumTiles (int *numTiles,
 {
     for (int i = 0; i < numLevels; i++)
     {
-	numTiles[i] = (levelSize (min, max, i, rmode) + size - 1) / size;
+        // use 64 bits to avoid int overflow if size is large.
+        Int64 l = levelSize (min, max, i, rmode);
+        numTiles[i] = (l + size - 1) / size;
     }
 }