stream_base,tls_wrap: notify on destruct

The TLSWrap constructor is passed a StreamBase* which it stores as
TLSWrap::stream_, and is used to receive/send data along the pipeline
(e.g. tls -> tcp). Problem is the lifetime of the instance that stream_
points to is independent of the lifetime of the TLSWrap instance. So
it's possible for stream_ to be delete'd while the TLSWrap instance is
still alive, allowing potential access to a then invalid pointer.

Fix by having the StreamBase destructor null out TLSWrap::stream_;
allowing all TLSWrap methods that rely on stream_ to do a check to see
if it's available.

While the test provided is fixed by this commit, it was also previously
fixed by 478fabf. Regardless, leave the test in for better testing.

PR-URL: #11947
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

src/stream_base.h

@@ -146,10 +146,14 @@ class StreamResource {
                          const uv_buf_t* buf,
                          uv_handle_type pending,
                          void* ctx);
+  typedef void (*DestructCb)(void* ctx);
 
   StreamResource() : bytes_read_(0) {
   }
-  virtual ~StreamResource() = default;
+  virtual ~StreamResource() {
+    if (!destruct_cb_.is_empty())
+      destruct_cb_.fn(destruct_cb_.ctx);
+  }
 
   virtual int DoShutdown(ShutdownWrap* req_wrap) = 0;
   virtual int DoTryWrite(uv_buf_t** bufs, size_t* count);
@@ -186,15 +190,18 @@ class StreamResource {
 
   inline void set_alloc_cb(Callback<AllocCb> c) { alloc_cb_ = c; }
   inline void set_read_cb(Callback<ReadCb> c) { read_cb_ = c; }
+  inline void set_destruct_cb(Callback<DestructCb> c) { destruct_cb_ = c; }
 
   inline Callback<AfterWriteCb> after_write_cb() { return after_write_cb_; }
   inline Callback<AllocCb> alloc_cb() { return alloc_cb_; }
   inline Callback<ReadCb> read_cb() { return read_cb_; }
+  inline Callback<DestructCb> destruct_cb() { return destruct_cb_; }
 
  private:
   Callback<AfterWriteCb> after_write_cb_;
   Callback<AllocCb> alloc_cb_;
   Callback<ReadCb> read_cb_;
+  Callback<DestructCb> destruct_cb_;
   uint64_t bytes_read_;
 
   friend class StreamBase;

src/tls_wrap.cc

@@ -64,6 +64,7 @@ TLSWrap::TLSWrap(Environment* env,
   stream_->set_after_write_cb({ OnAfterWriteImpl, this });
   stream_->set_alloc_cb({ OnAllocImpl, this });
   stream_->set_read_cb({ OnReadImpl, this });
+  stream_->set_destruct_cb({ OnDestructImpl, this });
 
   set_alloc_cb({ OnAllocSelf, this });
   set_read_cb({ OnReadSelf, this });
@@ -660,6 +661,12 @@ void TLSWrap::OnReadImpl(ssize_t nread,
 }
 
 
+void TLSWrap::OnDestructImpl(void* ctx) {
+  TLSWrap* wrap = static_cast<TLSWrap*>(ctx);
+  wrap->clear_stream();
+}
+
+
 void TLSWrap::OnAllocSelf(size_t suggested_size, uv_buf_t* buf, void* ctx) {
   buf->base = static_cast<char*>(node::Malloc(suggested_size));
   CHECK_NE(buf->base, nullptr);

src/tls_wrap.h

@@ -54,6 +54,8 @@ class TLSWrap : public AsyncWrap,
 
   size_t self_size() const override { return sizeof(*this); }
 
+  void clear_stream() { stream_ = nullptr; }
+
  protected:
   static const int kClearOutChunkSize = 16384;
 
@@ -121,6 +123,7 @@ class TLSWrap : public AsyncWrap,
                          const uv_buf_t* buf,
                          uv_handle_type pending,
                          void* ctx);
+  static void OnDestructImpl(void* ctx);
 
   void DoRead(ssize_t nread, const uv_buf_t* buf, uv_handle_type pending);
 

test/parallel/test-tls-retain-handle-no-abort.js

@@ -0,0 +1,42 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+
+if (!common.hasCrypto) {
+  common.skip('missing crypto');
+  return;
+}
+const tls = require('tls');
+const fs = require('fs');
+const util = require('util');
+
+const sent = 'hello world';
+const serverOptions = {
+  isServer: true,
+  key: fs.readFileSync(common.fixturesDir + '/keys/agent1-key.pem'),
+  cert: fs.readFileSync(common.fixturesDir + '/keys/agent1-cert.pem')
+};
+
+let ssl = null;
+
+process.on('exit', function() {
+  assert.ok(ssl !== null);
+  // If the internal pointer to stream_ isn't cleared properly then this
+  // will abort.
+  util.inspect(ssl);
+});
+
+const server = tls.createServer(serverOptions, function(s) {
+  s.on('data', function() { });
+  s.on('end', function() {
+    server.close();
+    s.destroy();
+  });
+}).listen(0, function() {
+  const c = new tls.TLSSocket();
+  ssl = c.ssl;
+  c.connect(this.address().port, function() {
+    c.end(sent);
+  });
+});