1 // Copyright 2013 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.
5 #ifndef CHROME_BROWSER_CHROMEOS_ATTESTATION_PLATFORM_VERIFICATION_FLOW_H_
6 #define CHROME_BROWSER_CHROMEOS_ATTESTATION_PLATFORM_VERIFICATION_FLOW_H_
10 #include "base/basictypes.h"
11 #include "base/callback.h"
12 #include "base/memory/ref_counted.h"
13 #include "base/memory/scoped_ptr.h"
14 #include "base/time/time.h"
15 #include "base/timer/timer.h"
18 class HostContentSettingsMap;
25 namespace cryptohome {
26 class AsyncMethodCaller;
29 namespace user_manager {
33 namespace user_prefs {
34 class PrefRegistrySyncable;
39 class CryptohomeClient;
41 namespace attestation {
43 class AttestationFlow;
44 class PlatformVerificationFlowTest;
46 // This class allows platform verification for the content protection use case.
47 // All methods must only be called on the UI thread. Example:
48 // scoped_refptr<PlatformVerificationFlow> verifier =
49 // new PlatformVerificationFlow();
50 // PlatformVerificationFlow::Callback callback = base::Bind(&MyCallback);
51 // verifier->ChallengePlatformKey(my_web_contents, "my_id", "some_challenge",
54 // This class is RefCountedThreadSafe because it may need to outlive its caller.
55 // The attestation flow that needs to happen to establish a certified platform
56 // key may take minutes on some hardware. This class will timeout after a much
57 // shorter time so the caller can proceed without platform verification but it
58 // is important that the pending operation be allowed to finish. If the
59 // attestation flow is aborted at any stage, it will need to start over. If we
60 // use weak pointers, the attestation flow will stop when the next callback is
61 // run. So we need the instance to stay alive until the platform key is fully
62 // certified so the next time ChallegePlatformKey() is invoked it will be quick.
63 class PlatformVerificationFlow
64 : public base::RefCountedThreadSafe<PlatformVerificationFlow> {
67 SUCCESS, // The operation succeeded.
68 INTERNAL_ERROR, // The operation failed unexpectedly.
69 PLATFORM_NOT_VERIFIED, // The platform cannot be verified. For example:
70 // - It is not a Chrome device.
71 // - It is not running a verified OS image.
72 USER_REJECTED, // The user explicitly rejected the operation.
73 POLICY_REJECTED, // The operation is not allowed by policy/settings.
74 TIMEOUT, // The operation timed out.
77 enum ConsentResponse {
78 CONSENT_RESPONSE_NONE,
79 CONSENT_RESPONSE_ALLOW,
80 CONSENT_RESPONSE_DENY,
83 // An interface which allows settings and UI to be abstracted for testing
84 // purposes. For normal operation the default implementation should be used.
87 virtual ~Delegate() {}
89 // This callback will be called when a user has given a |response| to a
90 // consent request of the specified |type|.
91 typedef base::Callback<void(ConsentResponse response)> ConsentCallback;
93 // Invokes consent UI within the context of |web_contents| and calls
94 // |callback| when the user responds.
95 // Precondition: The last committed URL for |web_contents| has a valid
97 virtual void ShowConsentPrompt(content::WebContents* web_contents,
98 const ConsentCallback& callback) = 0;
100 // Gets prefs associated with the given |web_contents|. If no prefs are
101 // associated with |web_contents| then NULL is returned.
102 virtual PrefService* GetPrefs(content::WebContents* web_contents) = 0;
104 // Gets the URL associated with the given |web_contents|.
105 virtual const GURL& GetURL(content::WebContents* web_contents) = 0;
107 // Gets the user associated with the given |web_contents|. NULL may be
109 virtual user_manager::User* GetUser(content::WebContents* web_contents) = 0;
111 // Gets the content settings map associated with the given |web_contents|.
112 virtual HostContentSettingsMap* GetContentSettings(
113 content::WebContents* web_contents) = 0;
115 // Returns true iff |web_contents| belongs to a guest or incognito session.
116 virtual bool IsGuestOrIncognito(content::WebContents* web_contents) = 0;
119 // This callback will be called when a challenge operation completes. If
120 // |result| is SUCCESS then |signed_data| holds the data which was signed
121 // by the platform key (this is the original challenge appended with a random
122 // nonce) and |signature| holds the RSA-PKCS1-v1.5 signature. The
123 // |platform_key_certificate| certifies the key used to generate the
124 // signature. This key may be generated on demand and is not guaranteed to
125 // persist across multiple calls to this method. The browser does not check
126 // the validity of |signature| or |platform_key_certificate|.
127 typedef base::Callback<void(Result result,
128 const std::string& signed_data,
129 const std::string& signature,
130 const std::string& platform_key_certificate)>
133 // A constructor that uses the default implementation of all dependencies
134 // including Delegate.
135 PlatformVerificationFlow();
137 // An alternate constructor which specifies dependent objects explicitly.
138 // This is useful in testing. The caller retains ownership of all pointers.
139 PlatformVerificationFlow(AttestationFlow* attestation_flow,
140 cryptohome::AsyncMethodCaller* async_caller,
141 CryptohomeClient* cryptohome_client,
144 // Invokes an asynchronous operation to challenge a platform key. Any user
145 // interaction will be associated with |web_contents|. The |service_id| is an
146 // arbitrary value but it should uniquely identify the origin of the request
147 // and should not be determined by that origin; its purpose is to prevent
148 // collusion between multiple services. The |challenge| is also an arbitrary
149 // value but it should be time sensitive or associated to some kind of session
150 // because its purpose is to prevent certificate replay. The |callback| will
151 // be called when the operation completes. The duration of the operation can
152 // vary depending on system state, hardware capabilities, and interaction with
154 void ChallengePlatformKey(content::WebContents* web_contents,
155 const std::string& service_id,
156 const std::string& challenge,
157 const ChallengeCallback& callback);
159 static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* prefs);
161 void set_timeout_delay(const base::TimeDelta& timeout_delay) {
162 timeout_delay_ = timeout_delay;
166 friend class base::RefCountedThreadSafe<PlatformVerificationFlow>;
167 friend class PlatformVerificationFlowTest;
169 // Holds the arguments of a ChallengePlatformKey call. This is convenient for
170 // use with base::Bind so we don't get too many arguments.
171 struct ChallengeContext {
172 ChallengeContext(content::WebContents* web_contents,
173 const std::string& service_id,
174 const std::string& challenge,
175 const ChallengeCallback& callback);
178 content::WebContents* web_contents;
179 std::string service_id;
180 std::string challenge;
181 ChallengeCallback callback;
184 ~PlatformVerificationFlow();
186 // Checks whether we need to prompt the user for consent before proceeding and
187 // invokes the consent UI if so. The arguments to ChallengePlatformKey are
188 // in |context| and |attestation_enrolled| specifies whether attestation has
189 // been enrolled for this device.
190 void CheckConsent(const ChallengeContext& context,
191 bool attestation_enrolled);
193 // A callback called when the user has given their consent response. The
194 // arguments to ChallengePlatformKey are in |context|. |consent_required| and
195 // |consent_response| indicate whether consent was required and user response,
196 // respectively. If the response indicates that the operation should proceed,
197 // this method invokes a certificate request.
198 void OnConsentResponse(const ChallengeContext& context,
199 bool consent_required,
200 ConsentResponse consent_response);
202 // Initiates the flow to get a platform key certificate. The arguments to
203 // ChallengePlatformKey are in |context|. |user_id| identifies the user for
204 // which to get a certificate. If |force_new_key| is true then any existing
205 // key for the same user and service will be ignored and a new key will be
206 // generated and certified.
207 void GetCertificate(const ChallengeContext& context,
208 const std::string& user_id,
211 // A callback called when an attestation certificate request operation
212 // completes. The arguments to ChallengePlatformKey are in |context|.
213 // |user_id| identifies the user for which the certificate was requested.
214 // |operation_success| is true iff the certificate request operation
215 // succeeded. |certificate| holds the certificate for the platform key on
216 // success. If the certificate request was successful, this method invokes a
217 // request to sign the challenge. If the operation timed out prior to this
218 // method being called, this method does nothing - notably, the callback is
220 void OnCertificateReady(const ChallengeContext& context,
221 const std::string& user_id,
222 scoped_ptr<base::Timer> timer,
223 bool operation_success,
224 const std::string& certificate);
226 // A callback run after a constant delay to handle timeouts for lengthy
227 // certificate requests. |context.callback| will be invoked with a TIMEOUT
229 void OnCertificateTimeout(const ChallengeContext& context);
231 // A callback called when a challenge signing request has completed. The
232 // |certificate| is the platform certificate for the key which signed the
233 // |challenge|. The arguments to ChallengePlatformKey are in |context|.
234 // |operation_success| is true iff the challenge signing operation was
235 // successful. If it was successful, |response_data| holds the challenge
236 // response and the method will invoke |context.callback|.
237 void OnChallengeReady(const ChallengeContext& context,
238 const std::string& certificate,
239 bool operation_success,
240 const std::string& response_data);
242 // Checks whether policy or profile settings associated with |web_contents|
243 // have attestation for content protection explicitly disabled.
244 bool IsAttestationEnabled(content::WebContents* web_contents);
246 // Updates user settings for the profile associated with |web_contents| based
247 // on the |consent_response| to the request of type |consent_type|.
248 bool UpdateSettings(content::WebContents* web_contents,
249 ConsentResponse consent_response);
251 // Finds the domain-specific consent pref in |content_settings| for |url|. If
252 // a pref exists for the domain, returns true and sets |pref_value| if it is
254 bool GetDomainPref(HostContentSettingsMap* content_settings,
258 // Records the domain-specific consent pref in |content_settings| for |url|.
259 // The pref will be set to |allow_domain|.
260 void RecordDomainConsent(HostContentSettingsMap* content_settings,
264 // Returns true iff |certificate| is an expired X.509 certificate.
265 bool IsExpired(const std::string& certificate);
267 AttestationFlow* attestation_flow_;
268 scoped_ptr<AttestationFlow> default_attestation_flow_;
269 cryptohome::AsyncMethodCaller* async_caller_;
270 CryptohomeClient* cryptohome_client_;
272 scoped_ptr<Delegate> default_delegate_;
273 base::TimeDelta timeout_delay_;
275 DISALLOW_COPY_AND_ASSIGN(PlatformVerificationFlow);
278 } // namespace attestation
279 } // namespace chromeos
281 #endif // CHROME_BROWSER_CHROMEOS_ATTESTATION_PLATFORM_VERIFICATION_FLOW_H_