WebAssembly: create code length data to avoid undefined bytes

src/main/java/wasm/WasmLoader.java

@@ -55,6 +55,7 @@
 import ghidra.util.Msg;
 import ghidra.util.exception.InvalidInputException;
 import ghidra.util.task.TaskMonitor;
+import wasm.format.StructureBuilder;
 import wasm.format.WasmConstants;
 import wasm.format.WasmEnums.WasmExternalKind;
 import wasm.format.WasmHeader;
@@ -339,6 +340,18 @@ private static void createGlobalBlock(Program program, DataType dataType, byte[]
 			Msg.error(WasmLoader.class, "Failed to create global block " + globalidx + " at " + dataStart, e);
 		}
 	}
+
+	private static void createCodeLengthData(Program program, MemoryBlock moduleBlock, WasmModule module) {
+		List<WasmImportEntry> imports = module.getImports(WasmExternalKind.EXT_FUNCTION);
+		List<WasmCodeEntry> codeEntries = module.getNonImportedFunctions();
+		for (int i = 0; i < codeEntries.size(); i++) {
+			WasmCodeEntry entry = codeEntries.get(i);
+			StructureBuilder builder = new StructureBuilder("code_" + (i + imports.size()));
+			builder.add(entry.getCodeSizeLeb128(), "code_size");
+			long offset = entry.getOffset() - entry.getCodeSizeLeb128().getLength();
+			createData(program, program.getListing(), moduleBlock.getStart().add(offset), builder.toStructure());
+		}
+	}
 	// #endregion
 
 	public void createImportExportSymbols(Program program, WasmModule module, int funcidx, Function function) throws Exception {
@@ -675,6 +688,8 @@ private void doLoad(ByteProvider provider, Program program, TaskMonitor monitor)
 			createData(program, program.getListing(), moduleBlock.getStart().add(section.getSectionOffset()), section.toDataType());
 		}
 
+		createCodeLengthData(program, moduleBlock, module);
+
 		createCustomSections(program, fileBytes, module, monitor);
 
 		loadFunctions(program, fileBytes, module, monitor);

src/main/java/wasm/format/sections/structures/WasmCodeEntry.java

@@ -47,6 +47,10 @@ public WasmCodeEntry(BinaryReader reader) throws IOException {
 		reader.setPointerIndex(codeOffset + codeSize.asLong());
 	}
 
+	public LEB128 getCodeSizeLeb128() {
+		return codeSize;
+	}
+
 	public long getCodeSize() {
 		return codeSize.asLong();
 	}