Limit the use of memory page

pywasm/__init__.py

@@ -40,6 +40,8 @@ def __init__(self, module: binary.Module, imps: typing.Dict = None, opts: typing
             if isinstance(e.desc, binary.MemoryType):
                 addr = execution.MemoryAddress(len(self.store.memory_list))
                 memory = imps[e.module][e.name]
+                if self.machine.opts.pages_limit > 0 and e.desc.limits.n > self.machine.opts.pages_limit:
+                    raise Exception('pywasm: out of memory limit')
                 memory.grow(e.desc.limits.n)
                 self.store.memory_list.append(memory)
                 extern_value_list.append(addr)

pywasm/execution.py

@@ -1032,6 +1032,8 @@ def grow_memory(config: Configuration, i: binary.Instruction):
         memory = config.store.memory_list[memory_addr]
         size = memory.size
         r = config.stack.pop().i32()
+        if config.opts.pages_limit > 0 and memory.size + r > config.opts.pages_limit:
+            raise Exception('pywasm: out of memory limit')
         try:
             memory.grow(r)
             config.stack.append(Value.from_i32(size))

pywasm/option.py

@@ -10,3 +10,5 @@ def __init__(self):
         self.cycle_limit = 0
         # Count the currently used cycles
         self.cycle = 0
+        # Memory page limit. 1 page = 65536 bytes
+        self.pages_limit = 0

setup.py

@@ -9,7 +9,7 @@
 
 setuptools.setup(
     name='pywasm',
-    version='1.0.2',
+    version='1.0.4',
     url='https://github.com/mohanson/pywasm',
     license='WTFPL',
     author='mohanson',