LibELF: Prevent negative index when determining dynamic symbol count

Author: https://github.com/Ollrogge
Commit: c87e1084b6
Pull-request: https://github.com/SerenityOS/serenity/pull/23587
Reviewed-by: https://github.com/ADKaster ✅

Userland/Libraries/LibELF/DynamicObject.cpp

@@ -242,6 +242,11 @@ void DynamicObject::parse()
         }
     }
 
+    if (highest_chain_idx < num_omitted_symbols) {
+        m_symbol_count = 0;
+        return;
+    }
+
     size_t amount_symbols = highest_chain_idx;
     u32 const* last_chain = &chains[highest_chain_idx - num_omitted_symbols];
     while ((*(last_chain++) & 1) == 0) {