Add regression test for issue #209

Besides the original fix, which catered to the subsequent output, the
potential DOS vulnerability due to a corrupted GD2 image file has been
fixed with c6bb583, and here we make sure that this very image is also
handled properly.

tests/gd2/.gitignore

@@ -1,4 +1,5 @@
 /bug_289
+/bug00209
 /bug00309
 /bug00354
 /gd2_empty_file

tests/gd2/CMakeLists.txt

@@ -1,5 +1,6 @@
 LIST(APPEND TESTS_FILES
 	bug_289
+	bug00209
 	bug00309
 	bug00354
 	gd2_empty_file

tests/gd2/Makemodule.am

@@ -1,5 +1,6 @@
 libgd_test_programs += \
 	gd2/bug_289 \
+	gd2/bug00209 \
 	gd2/bug00309 \
 	gd2/bug00354 \
 	gd2/gd2_empty_file \
@@ -20,6 +21,7 @@ endif
 
 EXTRA_DIST += \
 	gd2/CMakeLists.txt \
+	gd2/bug00209.gd2 \
 	gd2/bug00354a.gd2 \
 	gd2/bug00354b.gd2 \
 	gd2/conv_gd2_exp.gd2 \

tests/gd2/bug00209.c

@@ -0,0 +1,28 @@
+/**
+ * Regression test for github issue #209
+ *
+ * We're testing that bug00209.gd2, which claims to have 12336 x 48 pixels, but
+ * actually provides not enough image data, is rejected, i.e. that
+ * gdImageCreateFromGd2() returns NULL
+ *
+ * See <https://github.com/libgd/libgd/issues/209>.
+ */
+
+
+#include "gd.h"
+#include "gdtest.h"
+
+
+int main()
+{
+    gdImagePtr im;
+    FILE *fp;
+
+    fp = gdTestFileOpen2("gd2", "bug00209.gd2");
+    gdTestAssert(fp != NULL);
+    im = gdImageCreateFromGd2(fp);
+    gdTestAssert(im == NULL);
+    fclose(fp);
+
+    return gdNumFailures();
+}