Fix crash in one-argument imagecolortransparent

diff --git a/ext/gd/gd.c b/ext/gd/gd.c
index 70f06af4452e138cdf27d58202069598ad69d3e8..582e6a28c023a60c773e0b06e585c6d97df9471c 100644 (file)
--- a/ext/gd/gd.c
+++ b/ext/gd/gd.c
@@ -1414,7 +1414,7 @@ PHP_FUNCTION(imagecolortransparent)
 
        ZEND_FETCH_RESOURCE(im, gdImagePtr, IM, -1, "Image", GDG(le_gd));
 
-       if ((*COL) != NULL) {
+       if (COL != NULL && (*COL) != NULL) {
                col = (*COL)->value.lval;
                gdImageColorTransparent(im,col);
        }