An implementation of chrome.socket.secure().

chrome/browser/extensions/api/socket/tls_socket.cc

+// Copyright (c) 2013 The Chromium 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 "chrome/browser/extensions/api/socket/tls_socket.h"
+
+#include "base/logging.h"
+#include "chrome/browser/extensions/api/api_resource.h"
+#include "net/base/address_list.h"
+#include "net/base/ip_endpoint.h"
+#include "net/base/net_errors.h"
+#include "net/base/rand_callback.h"
+#include "net/socket/tcp_client_socket.h"
+
+namespace extensions {
+
+const char kTLSSocketTypeInvalidError[] =
+    "Cannot listen on a socket that's already connected.";
+
+TLSSocket::TLSSocket(net::StreamSocket* tls_socket,
+                     net::TCPClientSocket* underlying_tcp_socket,
+                     const std::string& owner_extension_id)
+    : Socket(owner_extension_id),
+      tls_socket_(tls_socket),
+      underlying_socket_(underlying_tcp_socket) {
+}
+
+TLSSocket::~TLSSocket() {
+  Disconnect();
+}
+
+void TLSSocket::Connect(const std::string& address,
+                        int port,
+                        const CompletionCallback& callback) {
+  callback.Run(net::ERR_CONNECTION_FAILED);
+}
+
+void TLSSocket::Disconnect() {
+  if (tls_socket_) {
+    tls_socket_->Disconnect();
+    tls_socket_.reset();
+  }
+}
+
+int TLSSocket::Bind(const std::string& address, int port) {
+  return net::ERR_NOT_IMPLEMENTED;
+}
+
+void TLSSocket::Read(int count,
+                     const ReadCompletionCallback& callback) {
+  DCHECK(!callback.is_null());
+
+  if (!read_callback_.is_null()) {
+    callback.Run(net::ERR_IO_PENDING, NULL);
+    return;
+  }
+
+  if (count <= 0) {
+    callback.Run(net::ERR_INVALID_ARGUMENT, NULL);
+    return;
+  }
+
+  if (!tls_socket_.get() || !IsConnected()) {
+    callback.Run(net::ERR_SOCKET_NOT_CONNECTED, NULL);
+    return;
+  }
+
+  read_callback_ = callback;
+  scoped_refptr<net::IOBuffer> io_buffer = new net::IOBuffer(count);
+  int result = tls_socket_->Read(
+      io_buffer.get(), count, base::Bind(&TLSSocket::OnReadComplete,
+                                         base::Unretained(this),
+                                         io_buffer));
+
+  if (result != net::ERR_IO_PENDING)
+    OnReadComplete(io_buffer, result);

[Ryan Sleevi, 2013/11/25 17:30:13]

This is a dangerous pattern (see comments in the TLS socket establishment).
Recursion with async callbacks can lead to dangerous patterns.

In particular, I'm concerned about the situation where the callback may want to
delete |this| - you now have two potential dangerous situations:

1) if member variables are ever accessed beyond this line, we've got danger
2) |callback| may cause re-entrancy back into the TLSSocket::Read() caller,
which can then cause dangerous side-effects

This may be an underlying/fundamentally scary part about the extensions code,
but it's why the net/ code is extremely careful to avoid this pattern. I
recently saw both 1 and 2 in Cast (ChromeCast) code, which was following the
pattern established here, so I'm extremely uncomfortable about it.

[Lally Singh, 2013/12/05 17:07:12]

Fair enough on both counts.  The existing APIs do the same as above.  To help
mitigate, I don't touch any  member variables after invoking the ReadCallback. 
The callback can delete 'this' without harm, and it can't invoke any other
methods on this instance after deleting it (it has to go through the
integer-handle API to get here, and that API will bounce just return an error).

+}
+
+void TLSSocket::OnReadComplete(scoped_refptr<net::IOBuffer> io_buffer,
+                               int result) {
+  DCHECK(!read_callback_.is_null());
+  read_callback_.Run(result, io_buffer);
+  read_callback_.Reset();
+}
+
+int TLSSocket::WriteImpl(net::IOBuffer* io_buffer,
+                         int io_buffer_size,
+                         const net::CompletionCallback& callback) {
+  if (!IsConnected())
+    return net::ERR_SOCKET_NOT_CONNECTED;
+  else
+   return tls_socket_->Write(io_buffer, io_buffer_size, callback);
+}
+
+void TLSSocket::RecvFrom(int count,
+                         const RecvFromCompletionCallback& callback) {
+  callback.Run(net::ERR_FAILED, NULL, NULL, 0);
+}
+
+void TLSSocket::SendTo(scoped_refptr<net::IOBuffer> io_buffer,
+                       int byte_count,
+                       const std::string& address,
+                       int port,
+                       const CompletionCallback& callback) {
+  callback.Run(net::ERR_FAILED);
+}
+
+bool TLSSocket::SetKeepAlive(bool enable, int delay) {
+  return IsConnected() && underlying_socket_->SetKeepAlive(enable, delay);
+}
+
+bool TLSSocket::SetNoDelay(bool no_delay) {
+  return IsConnected() && underlying_socket_->SetNoDelay(no_delay);
+}
+
+int TLSSocket::Listen(const std::string& address, int port, int backlog,
+                      std::string* error_msg) {
+  *error_msg = kTLSSocketTypeInvalidError;
+  return net::ERR_NOT_IMPLEMENTED;
+}
+
+void TLSSocket::Accept(const AcceptCompletionCallback &callback) {
+  callback.Run(net::ERR_FAILED, NULL);
+}
+
+bool TLSSocket::IsConnected() {
+  return tls_socket_.get() && tls_socket_->IsConnected() &&
+      underlying_socket_.get() && underlying_socket_->IsConnected();
+}
+
+bool TLSSocket::GetPeerAddress(net::IPEndPoint* address) {
+  return IsConnected() && underlying_socket_->GetPeerAddress(address);
+}
+
+bool TLSSocket::GetLocalAddress(net::IPEndPoint* address) {
+  return IsConnected() && underlying_socket_->GetLocalAddress(address);
+}
+
+Socket::SocketType TLSSocket::GetSocketType() const {
+  return Socket::TYPE_TCP;
+}
+
+}  // namespace extensions