TIFFWriteDirectorySec: avoid assertion.

Fixes http://bugzilla.maptools.org/show_bug.cgi?id=2795. CVE-2018-10963

Change-Id: I451e25eb6daa43422ed8a8b241203c7d5072c727

diff --git a/libtiff/tif_dirwrite.c b/libtiff/tif_dirwrite.c
old mode 100644 (file)
new mode 100755 (executable)
index c68d6d2..0cd76ff
--- a/libtiff/tif_dirwrite.c
+++ b/libtiff/tif_dirwrite.c
@@ -697,8 +697,11 @@ TIFFWriteDirectorySec(TIFF* tif, int isimage, int imagedone, uint64* pdiroff)
                                                                }
                                                                break;
                                                        default:
-                                                               assert(0);   /* we should never get here */
-                                                               break;
+                                                               TIFFErrorExt(tif->tif_clientdata, module,
+                                                                       "Cannot write tag %d (%s)",
+                                                                           TIFFFieldTag(o),
+                                                                           o->field_name ? o->field_name : "unknown");
+                                                               goto bad;
                                                }
                                        }
                                }