[wasm] Enforce module size limit early enough

src/wasm/wasm-js.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/api-natives.h"
 #include "src/api.h"
 #include "src/asmjs/asm-js.h"
 #include "src/asmjs/asm-typer.h"
 #include "src/asmjs/asm-wasm-builder.h"
 #include "src/assert-scope.h"
@@ skipping 133 matching lines @@
     start =
         reinterpret_cast<const byte*>(contents.Data()) + array->ByteOffset();
     end = start + array->ByteLength();
 
   } else {
     thrower->TypeError("Argument 0 must be a buffer source");
   }
   if (start == nullptr || end == start) {
     thrower->CompileError("BufferSource argument is empty");
   }
+  if (end - start > static_cast<ssize_t>(i::wasm::kV8MaxWasmModuleSize)) {
+    thrower->RangeError("buffer source exceeds maximum size of %" PRId64
+                        " (is %" PRId64 ")",
+                        static_cast<int64_t>(i::wasm::kV8MaxWasmModuleSize),

[titzer, 2017/02/21 15:10:22]

for size_t you can use %zu as the format string.

[Clemens Hammacher, 2017/02/21 17:48:16]

Done.

+                        static_cast<int64_t>(end - start));
+  }
+  if (thrower->error()) return i::wasm::ModuleWireBytes(nullptr, nullptr);
   // TODO(titzer): use the handle as well?
   return i::wasm::ModuleWireBytes(start, end);
 }
 
 i::MaybeHandle<i::JSReceiver> GetSecondArgumentAsImports(
     const v8::FunctionCallbackInfo<v8::Value>& args, ErrorThrower* thrower) {
   if (args.Length() < 2) return {};
   if (args[1]->IsUndefined()) return {};
 
   if (!args[1]->IsObject()) {
@@ skipping 748 matching lines @@
   i::Handle<i::Symbol> symbol(isolate->context()->wasm_memory_sym(), isolate);
   return HasBrand(value, symbol);
 }
 
 bool WasmJs::IsWasmTableObject(Isolate* isolate, Handle<Object> value) {
   i::Handle<i::Symbol> symbol(isolate->context()->wasm_table_sym(), isolate);
   return HasBrand(value, symbol);
 }
 }  // namespace internal
 }  // namespace v8