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      1 //
      2 // Copyright (C) 2013 The Android Open Source Project
      3 //
      4 // Licensed under the Apache License, Version 2.0 (the "License");
      5 // you may not use this file except in compliance with the License.
      6 // You may obtain a copy of the License at
      7 //
      8 //      http://www.apache.org/licenses/LICENSE-2.0
      9 //
     10 // Unless required by applicable law or agreed to in writing, software
     11 // distributed under the License is distributed on an "AS IS" BASIS,
     12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13 // See the License for the specific language governing permissions and
     14 // limitations under the License.
     15 //
     16 
     17 #ifndef SHILL_CRYPTO_UTIL_PROXY_H_
     18 #define SHILL_CRYPTO_UTIL_PROXY_H_
     19 
     20 #include <memory>
     21 #include <string>
     22 #include <vector>
     23 
     24 #include <base/cancelable_callback.h>
     25 #include <base/macros.h>
     26 #include <base/memory/weak_ptr.h>
     27 #include <base/strings/stringprintf.h>
     28 #include <brillo/minijail/minijail.h>
     29 #include <gtest/gtest_prod.h>  // for FRIEND_TEST
     30 
     31 #include "shill/callbacks.h"
     32 #include "shill/error.h"
     33 #include "shill/net/io_handler.h"
     34 #include "shill/shims/protos/crypto_util.pb.h"
     35 
     36 namespace shill {
     37 
     38 class EventDispatcher;
     39 class FileIO;
     40 class ProcessManager;
     41 
     42 class CryptoUtilProxy : public base::SupportsWeakPtr<CryptoUtilProxy> {
     43  public:
     44   static const char kCommandVerify[];
     45   static const char kCommandEncrypt[];
     46   static const char kCryptoUtilShimPath[];
     47 
     48   explicit CryptoUtilProxy(EventDispatcher* dispatcher);
     49   virtual ~CryptoUtilProxy();
     50 
     51   // Verify credentials for the currently connected endpoint of
     52   // |connected_service|.  This is a fairly expensive/time consuming operation.
     53   // Returns true if we've succeeded in kicking off a job to an external shim
     54   // to verify credentials.  |result_callback| will be called with the actual
     55   // result of the job, either true, or false with a descriptive error.
     56   //
     57   // |certificate| should be a device certificate in PEM format.
     58   // |public_key| is a base64 encoded DER RSAPublicKey format public key.
     59   // |nonce| has no particular format requirements.
     60   // |signed_data| is the base64 encoded signed string given by the device.
     61   // |destination_udn| has no format requirements.
     62   // |ssid| has no constraints.
     63   // |bssid| should be in the human readable format: 00:11:22:33:44:55.
     64   virtual bool VerifyDestination(const std::string& certificate,
     65                                  const std::string& public_key,
     66                                  const std::string& nonce,
     67                                  const std::string& signed_data,
     68                                  const std::string& destination_udn,
     69                                  const std::vector<uint8_t>& ssid,
     70                                  const std::string& bssid,
     71                                  const ResultBoolCallback& result_callback,
     72                                  Error* error);
     73 
     74   // Encrypt |data| under |public_key|.  This is a fairly time consuming
     75   // process.  Returns true if we've succeeded in kicking off a job to an
     76   // external shim to sign the data.  |result_callback| will be called with the
     77   // results of the operation: an empty string and a descriptive error or the
     78   // base64 encoded bytes of the encrypted data.
     79   //
     80   // |public_key| is a base64 encoded DER RSAPublicKey format public key.
     81   // |data| has no particular format requirements.
     82   virtual bool EncryptData(const std::string& public_key,
     83                            const std::string& data,
     84                            const ResultStringCallback& result_callback,
     85                            Error* error);
     86 
     87  private:
     88   friend class CryptoUtilProxyTest;
     89   friend class MockCryptoUtilProxy;
     90   FRIEND_TEST(CryptoUtilProxyTest, BasicAPIUsage);
     91   FRIEND_TEST(CryptoUtilProxyTest, FailuresReturnValues);
     92   FRIEND_TEST(CryptoUtilProxyTest, OnlyOneInstanceInFlightAtATime);
     93   FRIEND_TEST(CryptoUtilProxyTest, ShimLifeTime);
     94   FRIEND_TEST(CryptoUtilProxyTest, TimeoutsTriggerFailure);
     95   FRIEND_TEST(CryptoUtilProxyTest, ShimCleanedBeforeCallback);
     96 
     97   static const char kDestinationVerificationUser[];
     98   static const uint64_t kRequiredCapabilities;
     99   static const int kShimJobTimeoutMilliseconds;
    100 
    101   // Helper method for parsing the proto buffer return codes sent back by the
    102   // shim.
    103   static bool ParseResponseReturnCode(int proto_return_code, Error* e);
    104 
    105   // Kick off a run of the shim to verify credentials or sign data.  Callers
    106   // pass in the command they want to run on the shim (literally a command line
    107   // argument to the shim), and a handler to handle the result.  The handler is
    108   // called both on errors, timeouts, and success.  Behind the scenes, we first
    109   // send |input| down to the shim through a pipe to its stdin, then wait for
    110   // bytes to comes back over a pipe connected to the shim's stdout.
    111   virtual bool StartShimForCommand(const std::string& command,
    112                                    const std::string& input,
    113                                    const StringCallback& result_handler);
    114   // This is the big hammer we use to clean up past shim state.
    115   virtual void CleanupShim(const Error& shim_result);
    116   virtual void OnShimDeath(int exit_status);
    117 
    118   // Callbacks that handle IO operations between shill and the shim.
    119   // Called on changes in file descriptor state.
    120   void HandleShimStdinReady(int fd);
    121   void HandleShimOutput(InputData* data);
    122   void HandleShimReadError(const std::string& error_msg);
    123   void HandleShimError(const Error& error);
    124   void HandleShimTimeout();
    125   // Used to handle the final result of both operations.  |result| is a
    126   // seriallized protocol buffer or an empty string on error.  On error,
    127   // |error| is filled in with an appropriate error condition.
    128   // |result_callback| is a callback from the original caller (the manager).
    129   void HandleVerifyResult(const ResultBoolCallback& result_handler,
    130                           const std::string& result,
    131                           const Error& error);
    132   void HandleEncryptResult(const ResultStringCallback& result_handler,
    133                            const std::string& result,
    134                            const Error& error);
    135 
    136   EventDispatcher* dispatcher_;
    137   ProcessManager* process_manager_;
    138   FileIO* file_io_;
    139   std::string input_buffer_;
    140   std::string::const_iterator next_input_byte_;
    141   std::string output_buffer_;
    142   int shim_stdin_;
    143   int shim_stdout_;
    144   pid_t shim_pid_;
    145   std::unique_ptr<IOHandler> shim_stdin_handler_;
    146   std::unique_ptr<IOHandler> shim_stdout_handler_;
    147   Error shim_result_;
    148   StringCallback result_handler_;
    149   base::CancelableClosure shim_job_timeout_callback_;
    150 
    151   DISALLOW_COPY_AND_ASSIGN(CryptoUtilProxy);
    152 };
    153 
    154 }  // namespace shill
    155 
    156 #endif  // SHILL_CRYPTO_UTIL_PROXY_H_
    157