net: Add fuzzer for HostResolverImpl.

net/dns/dns_socket_pool.cc

 // Copyright (c) 2012 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 "net/dns/dns_socket_pool.h"
 
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/rand_util.h"
 #include "base/stl_util.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/client_socket_factory.h"
 #include "net/socket/stream_socket.h"
 #include "net/udp/datagram_client_socket.h"
 
 namespace net {
 
 namespace {
 
 // When we initialize the SocketPool, we allocate kInitialPoolSize sockets.
 // When we allocate a socket, we ensure we have at least kAllocateMinSize
 // sockets to choose from.  Freed sockets are not retained.
 
 // On Windows, we can't request specific (random) ports, since that will
 // trigger firewall prompts, so request default ones, but keep a pile of
 // them.  Everywhere else, request fresh, random ports each time.
 #if defined(OS_WIN)
 const DatagramSocket::BindType kBindType = DatagramSocket::DEFAULT_BIND;
 const unsigned kInitialPoolSize = 256;
 const unsigned kAllocateMinSize = 256;
 #else
 const DatagramSocket::BindType kBindType = DatagramSocket::RANDOM_BIND;
 const unsigned kInitialPoolSize = 0;
 const unsigned kAllocateMinSize = 1;
 #endif
 
 } // namespace
 
-DnsSocketPool::DnsSocketPool(ClientSocketFactory* socket_factory)
+DnsSocketPool::DnsSocketPool(ClientSocketFactory* socket_factory,
+                             const RandIntCallback& rand_int_callback)
     : socket_factory_(socket_factory),
+      rand_int_callback_(rand_int_callback),
       net_log_(NULL),
       nameservers_(NULL),
-      initialized_(false) {
-}
+      initialized_(false) {}
 
 void DnsSocketPool::InitializeInternal(
     const std::vector<IPEndPoint>* nameservers,
     NetLog* net_log) {
   DCHECK(nameservers);
   DCHECK(!initialized_);
 
   net_log_ = net_log;
   nameservers_ = nameservers;
   initialized_ = true;
@@ skipping 10 matching lines @@
 }
 
 std::unique_ptr<DatagramClientSocket> DnsSocketPool::CreateConnectedSocket(
     unsigned server_index) {
   DCHECK_LT(server_index, nameservers_->size());
 
   std::unique_ptr<DatagramClientSocket> socket;
 
   NetLog::Source no_source;
   socket = socket_factory_->CreateDatagramClientSocket(
-      kBindType, base::Bind(&base::RandInt), net_log_, no_source);
+      kBindType, rand_int_callback_, net_log_, no_source);
 
   if (socket.get()) {
     int rv = socket->Connect((*nameservers_)[server_index]);
     if (rv != OK) {
-      VLOG(1) << "Failed to connect socket: " << rv;
+      DVLOG(1) << "Failed to connect socket: " << rv;
       socket.reset();
     }
   } else {
-    LOG(WARNING) << "Failed to create socket.";
+    DVLOG(1) << "Failed to create socket.";
   }
 
   return socket;
 }
 
 class NullDnsSocketPool : public DnsSocketPool {
  public:
-  NullDnsSocketPool(ClientSocketFactory* factory)
-     : DnsSocketPool(factory) {
-  }
+  NullDnsSocketPool(ClientSocketFactory* factory,
+                    const RandIntCallback& rand_int_callback)
+      : DnsSocketPool(factory, rand_int_callback) {}
 
   void Initialize(const std::vector<IPEndPoint>* nameservers,
                   NetLog* net_log) override {
     InitializeInternal(nameservers, net_log);
   }
 
   std::unique_ptr<DatagramClientSocket> AllocateSocket(
       unsigned server_index) override {
     return CreateConnectedSocket(server_index);
   }
 
   void FreeSocket(unsigned server_index,
                   std::unique_ptr<DatagramClientSocket> socket) override {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(NullDnsSocketPool);
 };
 
 // static
 std::unique_ptr<DnsSocketPool> DnsSocketPool::CreateNull(
-    ClientSocketFactory* factory) {
-  return std::unique_ptr<DnsSocketPool>(new NullDnsSocketPool(factory));
+    ClientSocketFactory* factory,
+    const RandIntCallback& rand_int_callback) {
+  return std::unique_ptr<DnsSocketPool>(
+      new NullDnsSocketPool(factory, rand_int_callback));
 }
 
 class DefaultDnsSocketPool : public DnsSocketPool {
  public:
-  DefaultDnsSocketPool(ClientSocketFactory* factory)
-     : DnsSocketPool(factory) {
-  };
+  DefaultDnsSocketPool(ClientSocketFactory* factory,
+                       const RandIntCallback& rand_int_callback)
+      : DnsSocketPool(factory, rand_int_callback){};
 
   ~DefaultDnsSocketPool() override;
 
   void Initialize(const std::vector<IPEndPoint>* nameservers,
                   NetLog* net_log) override;
 
   std::unique_ptr<DatagramClientSocket> AllocateSocket(
       unsigned server_index) override;
 
   void FreeSocket(unsigned server_index,
                   std::unique_ptr<DatagramClientSocket> socket) override;
 
  private:
   void FillPool(unsigned server_index, unsigned size);
 
   typedef std::vector<DatagramClientSocket*> SocketVector;
 
   std::vector<SocketVector> pools_;
 
   DISALLOW_COPY_AND_ASSIGN(DefaultDnsSocketPool);
 };
 
 // static
 std::unique_ptr<DnsSocketPool> DnsSocketPool::CreateDefault(
-    ClientSocketFactory* factory) {
-  return std::unique_ptr<DnsSocketPool>(new DefaultDnsSocketPool(factory));
+    ClientSocketFactory* factory,
+    const RandIntCallback& rand_int_callback) {
+  return std::unique_ptr<DnsSocketPool>(
+      new DefaultDnsSocketPool(factory, rand_int_callback));
 }
 
 void DefaultDnsSocketPool::Initialize(
     const std::vector<IPEndPoint>* nameservers,
     NetLog* net_log) {
   InitializeInternal(nameservers, net_log);
 
   DCHECK(pools_.empty());
   const unsigned num_servers = nameservers->size();
   pools_.resize(num_servers);
   for (unsigned server_index = 0; server_index < num_servers; ++server_index)
     FillPool(server_index, kInitialPoolSize);
 }
 
 DefaultDnsSocketPool::~DefaultDnsSocketPool() {
   unsigned num_servers = pools_.size();
   for (unsigned server_index = 0; server_index < num_servers; ++server_index) {
     SocketVector& pool = pools_[server_index];
     STLDeleteElements(&pool);
   }
 }
 
 std::unique_ptr<DatagramClientSocket> DefaultDnsSocketPool::AllocateSocket(
     unsigned server_index) {
   DCHECK_LT(server_index, pools_.size());
   SocketVector& pool = pools_[server_index];
 
   FillPool(server_index, kAllocateMinSize);
   if (pool.size() == 0) {
-    LOG(WARNING) << "No DNS sockets available in pool " << server_index << "!";
+    DVLOG(1) << "No DNS sockets available in pool " << server_index << "!";
     return std::unique_ptr<DatagramClientSocket>();
   }
 
   if (pool.size() < kAllocateMinSize) {
-    LOG(WARNING) << "Low DNS port entropy: wanted " << kAllocateMinSize
-                 << " sockets to choose from, but only have " << pool.size()
-                 << " in pool " << server_index << ".";
+    DVLOG(1) << "Low DNS port entropy: wanted " << kAllocateMinSize
+             << " sockets to choose from, but only have " << pool.size()
+             << " in pool " << server_index << ".";
   }
 
-  unsigned socket_index = base::RandInt(0, pool.size() - 1);
+  unsigned socket_index = rand_int_callback().Run(0, pool.size() - 1);

[eroman, 2016/06/01 01:47:21]

Rather than exposing the callback , how about exposing a function that does
this.

Say, GetRandomInt(.., ...)

(the callback is more of an implementation detail of the base class).

[mmenke, 2016/06/01 21:21:51]

Done.  Agree it's a bit nicer, though since we're passing it to the base class
in our constructor, not exactly a hidden implementation detail.

   DatagramClientSocket* socket = pool[socket_index];
   pool[socket_index] = pool.back();
   pool.pop_back();
 
   return std::unique_ptr<DatagramClientSocket>(socket);
 }
 
 void DefaultDnsSocketPool::FreeSocket(
     unsigned server_index,
     std::unique_ptr<DatagramClientSocket> socket) {
   DCHECK_LT(server_index, pools_.size());
 }
 
 void DefaultDnsSocketPool::FillPool(unsigned server_index, unsigned size) {
   SocketVector& pool = pools_[server_index];
 
   for (unsigned pool_index = pool.size(); pool_index < size; ++pool_index) {
     DatagramClientSocket* socket =
         CreateConnectedSocket(server_index).release();
     if (!socket)
       break;
     pool.push_back(socket);
   }
 }
 
 } // namespace net