Fortify against corrupted font.

third_party/sfntly/src/subsetter/subsetter_impl.cc

 /*
  * Copyright 2011 Google Inc. All Rights Reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
@@ skipping 136 matching lines @@
   UnicodeString font_string = UnicodeString::fromUTF8(font_name);
   if (font_string.isEmpty())
     return false;
   UnicodeString regular_suffix = UnicodeString::fromUTF8(" Regular");
   UnicodeString alt_font_string = font_string;
   alt_font_string += regular_suffix;
 
   typedef std::map<int32_t, UnicodeString> NameMap;
   NameMap names;
   NameTablePtr name_table = down_cast<NameTable*>(font->GetTable(Tag::name));
+  if (name_table == NULL) {
+    return false;
+  }
 
   for (int32_t i = 0; i < name_table->NameCount(); ++i) {
     switch(name_table->NameId(i)) {
       case NameId::kFontFamilyName:
       case NameId::kFontSubfamilyName:
       case NameId::kFullFontName:
       case NameId::kPreferredFamily:
       case NameId::kPreferredSubfamily:
       case NameId::kWWSFamilyName:
       case NameId::kWWSSubfamilyName: {
@@ skipping 161 matching lines @@
       TableBuilderPtr dereference;
       dereference.Attach(
           font_builder->NewTableBuilder(i->first, i->second->ReadFontData()));
     }
   }
 
   return font_builder->Build();
 }
 
 }  // namespace sfntly