chromeos/dbus/easy_unlock_client.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROMEOS_DBUS_EASY_UNLOCK_CLIENT_H_
   6 #define CHROMEOS_DBUS_EASY_UNLOCK_CLIENT_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11 #include "base/callback.h"
  12 #include "chromeos/chromeos_export.h"
  13 #include "chromeos/dbus/dbus_client.h"
  14
  15 namespace chromeos {
  16
  17 // Client for calling EasyUnlock dbus service. The service provides
  18 // methods used by Easy Unlock for establishing secure communication channel
  19 // over (unsecure) bluetooth with devices registered to unlock ChromeOS.
  20 // Ideally, this would be done in Chrome, but unfortunatelly, the library used
  21 // for wrapping and unwrapping messages sent over the communication channel
  22 // depends on OpenSSL for encryption, which is not currently available in
  23 // Chrome. To work around this, the message processing will be done in ChromeOS,
  24 // where OpenSSL is already supported.
  25 // TODO(tbarzic): Get rid of this client when Chrome switches from NSS to
  26 // OpenSSL (http://crbug.com/338888).
  27 class CHROMEOS_EXPORT EasyUnlockClient : public DBusClient {
  28  public:
  29   virtual ~EasyUnlockClient();
  30
  31   typedef base::Callback<void(const std::string& data)> DataCallback;
  32
  33   // Callback for |GenerateEcP256KeyPair|. Carries the generated keys.
  34   typedef base::Callback<void(const std::string& private_key,
  35                               const std::string& public_key)>
  36       KeyPairCallback;
  37
  38   // Generates ECDSA key pair using P256 curve.
  39   // The created keys should only be used with this client.
  40   virtual void GenerateEcP256KeyPair(const KeyPairCallback& callback) = 0;
  41
  42   // Parameters used to create a secure message.
  43   struct CreateSecureMessageOptions {
  44     CreateSecureMessageOptions();
  45     ~CreateSecureMessageOptions();
  46
  47     // The key used to sign, and if needed, encrypt the message. If encryption
  48     // is required, the key must be symetric.
  49     std::string key;
  50
  51     // Data associated with the message. The data will not actually be added to
  52     // the message, but it will be used while signing the message (the receiver
  53     // will use the same data to authenticate the signature).
  54     std::string associated_data;
  55
  56     // Metadata added to the message header.
  57     std::string public_metadata;
  58
  59     // The key id added to the message header. Has to be set if the message is
  60     // signed with private asymetric key. This value is used by the receiver to
  61     // identify the key that should be used to verify the signature.
  62     std::string verification_key_id;
  63
  64     // Key id added to the message header. Used by the message receiver to
  65     // identify the key that should be used to decrypt the message.
  66     std::string decryption_key_id;
  67
  68     // The encryption algorithm to use for encrypting the message.
  69     std::string encryption_type;
  70
  71     // The algorithm to use to sign the message.
  72     std::string signature_type;
  73
  74    private:
  75     DISALLOW_COPY_AND_ASSIGN(CreateSecureMessageOptions);
  76   };
  77
  78   // Parameters used to unwrap a securemessage.
  79   struct UnwrapSecureMessageOptions {
  80     UnwrapSecureMessageOptions();
  81     ~UnwrapSecureMessageOptions();
  82
  83     // The key used to authenticate message signature and, if needed, decrypt
  84     // the message. If the message is encrypted, only symetric key can be used.
  85     std::string key;
  86
  87     // Data associated with the message. Message authentication will succeed
  88     // only if the message was created with the same associated data.
  89     std::string associated_data;
  90
  91     // The encryption algorithm to use for decrypting the message.
  92     std::string encryption_type;
  93
  94     // The algorithm that should be used to verify the message signature.
  95     std::string signature_type;
  96
  97    private:
  98     DISALLOW_COPY_AND_ASSIGN(UnwrapSecureMessageOptions);
  99   };
 100
 101   // Given a private and a public key, creates a symetric secret key using
 102   // EC Diffe-Hellman key exchange. The provided keys come from different
 103   // asymetric key pairs, and are expected to be in the same format as the ones
 104   // returned by |GenerateEcP256KeyAgreement|. Reversing key pairs from which
 105   // private and public key come generates the same secret key.
 106   virtual void PerformECDHKeyAgreement(const std::string& private_key,
 107                                        const std::string& public_key,
 108                                        const DataCallback& callback) = 0;
 109
 110   // Creates signed and, if specified, encrypted message in format used by Easy
 111   // Unlock.
 112   // |payload|: The cleartext message body.
 113   // |options|: The message parameters used for creating the secure message.
 114   // |callback|: Called with the created message. On failure, the message will
 115   //     be empty.
 116   virtual void CreateSecureMessage(const std::string& payload,
 117                                    const CreateSecureMessageOptions& options,
 118                                    const DataCallback& callback) = 0;
 119
 120   // Authenticates and, if specified, decrypts a secure message.
 121   // |message|: The message to unwrap. It is in the same format as the message
 122   //     returned by |CreateSecureMessage|.
 123   // |options|: The parameters that should be used to unwrap the message.
 124   // |callback|: Called with the cleartext message header and body in a signle
 125   //     protobuf. If the message could not be authenticated or decrypted, it
 126   //     will be called with an empty string.
 127   virtual void UnwrapSecureMessage(const std::string& message,
 128                                    const UnwrapSecureMessageOptions& options,
 129                                    const DataCallback& callback) = 0;
 130
 131   // Factory function, creates a new instance and returns ownership.
 132   // For normal usage, access the singleton via DBusThreadManager::Get().
 133   static EasyUnlockClient* Create();
 134
 135  protected:
 136   // Create() should be used instead.
 137   EasyUnlockClient();
 138
 139  private:
 140   DISALLOW_COPY_AND_ASSIGN(EasyUnlockClient);
 141 };
 142
 143 }  // namespace chromeos
 144
 145 #endif  // CHROMEOS_DBUS_EASY_UNLOCK_CLIENT_H_