windowscodecs: Properly handle empty GIF extension blocks.

7eaff177 · Dmitry Timoshkov · Alexandre Julliard · f46aa66c · 7eaff177
Commit 7eaff177 authored Jul 15, 2015 by Dmitry Timoshkov Committed by Alexandre Julliard Jul 15, 2015
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Showing with 11 additions and 3 deletions

ungif.c dlls/windowscodecs/ungif.c +11 -3

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--- a/dlls/windowscodecs/ungif.c
+++ b/dlls/windowscodecs/ungif.c
@@ -932,9 +932,17 @@ DGifSlurp(GifFileType * GifFile) {

              Extensions->Function = Function;

-              /* Create an extension block with our data */
-              if (AddExtensionBlock(Extensions, ExtData[0], &ExtData[1]) == GIF_ERROR)
-                  return (GIF_ERROR);
+              if (ExtData)
+              {
+                  /* Create an extension block with our data */
+                  if (AddExtensionBlock(Extensions, ExtData[0], &ExtData[1]) == GIF_ERROR)
+                      return (GIF_ERROR);
+              }
+              else /* Empty extension block */
+              {
+                  if (AddExtensionBlock(Extensions, 0, NULL) == GIF_ERROR)
+                      return (GIF_ERROR);
+              }

              while (ExtData != NULL) {
                  int Len;