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1 // Copyright (c) 2011 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 NET_BASE_SSL_CONFIG_SERVICE_H_
6 #define NET_BASE_SSL_CONFIG_SERVICE_H_
7 #pragma once
8 
9 #include <vector>
10 
11 #include "base/basictypes.h"
12 #include "base/memory/ref_counted.h"
13 #include "base/observer_list.h"
14 #include "net/base/net_export.h"
15 #include "net/base/x509_certificate.h"
16 
17 namespace net {
18 
19 // A collection of SSL-related configuration settings.
20 struct NET_EXPORT SSLConfig {
21   // Default to revocation checking.
22   // Default to SSL 3.0 on and TLS 1.0 on.
23   SSLConfig();
24   ~SSLConfig();
25 
26   // Returns true if |cert| is one of the certs in |allowed_bad_certs|.
27   bool IsAllowedBadCert(X509Certificate* cert) const;
28 
29   bool rev_checking_enabled;  // True if server certificate revocation
30                               // checking is enabled.
31   // SSL 2.0 is not supported.
32   bool ssl3_enabled;  // True if SSL 3.0 is enabled.
33   bool tls1_enabled;  // True if TLS 1.0 is enabled.
34   bool dnssec_enabled;  // True if we'll accept DNSSEC chains in certificates.
35   // True if we'll do async checks for certificate provenance using DNS.
36   bool dns_cert_provenance_checking_enabled;
37 
38   // Cipher suites which should be explicitly prevented from being used in
39   // addition to those disabled by the net built-in policy -- by default, all
40   // cipher suites supported by the underlying SSL implementation will be
41   // enabled except for:
42   // - Null encryption cipher suites.
43   // - Weak cipher suites: < 80 bits of security strength.
44   // - FORTEZZA cipher suites (obsolete).
45   // - IDEA cipher suites (RFC 5469 explains why).
46   // - Anonymous cipher suites.
47   // The ciphers listed in |disabled_cipher_suites| will be removed in addition
48   // to the above statically defined disable list.
49   //
50   // Though cipher suites are sent in TLS as "uint8 CipherSuite[2]", in
51   // big-endian form, they should be declared in host byte order, with the
52   // first uint8 occupying the most significant byte.
53   // Ex: To disable TLS_RSA_WITH_RC4_128_MD5, specify 0x0004, while to
54   // disable TLS_ECDH_ECDSA_WITH_RC4_128_SHA, specify 0xC002.
55   //
56   // TODO(rsleevi): Not implemented when using Schannel.
57   std::vector<uint16> disabled_cipher_suites;
58 
59   bool false_start_enabled;  // True if we'll use TLS False Start.
60 
61   // TODO(wtc): move the following members to a new SSLParams structure.  They
62   // are not SSL configuration settings.
63 
64   struct CertAndStatus {
65     CertAndStatus();
66     ~CertAndStatus();
67 
68     scoped_refptr<X509Certificate> cert;
69     int cert_status;
70   };
71 
72   // Add any known-bad SSL certificate (with its cert status) to
73   // |allowed_bad_certs| that should not trigger an ERR_CERT_* error when
74   // calling SSLClientSocket::Connect.  This would normally be done in
75   // response to the user explicitly accepting the bad certificate.
76   std::vector<CertAndStatus> allowed_bad_certs;
77 
78   // True if we should send client_cert to the server.
79   bool send_client_cert;
80 
81   bool verify_ev_cert;  // True if we should verify the certificate for EV.
82 
83   bool ssl3_fallback;  // True if we are falling back to SSL 3.0 (one still
84                        // needs to clear tls1_enabled).
85 
86   // The list of application level protocols supported. If set, this will
87   // enable Next Protocol Negotiation (if supported). This is a list of 8-bit
88   // length prefixed strings. The order of the protocols doesn't matter expect
89   // for one case: if the server supports Next Protocol Negotiation, but there
90   // is no overlap between the server's and client's protocol sets, then the
91   // first protocol in this list will be requested by the client.
92   std::string next_protos;
93 
94   scoped_refptr<X509Certificate> client_cert;
95 };
96 
97 // The interface for retrieving the SSL configuration.  This interface
98 // does not cover setting the SSL configuration, as on some systems, the
99 // SSLConfigService objects may not have direct access to the configuration, or
100 // live longer than the configuration preferences.
101 class NET_EXPORT SSLConfigService : public base::RefCountedThreadSafe<SSLConfigService> {
102  public:
103   // Observer is notified when SSL config settings have changed.
104   class NET_EXPORT Observer {
105    public:
106     // Notify observers if SSL settings have changed.  We don't check all of the
107     // data in SSLConfig, just those that qualify as a user config change.
108     // The following settings are considered user changes:
109     //     rev_checking_enabled
110     //     ssl3_enabled
111     //     tls1_enabled
112     virtual void OnSSLConfigChanged() = 0;
113 
114    protected:
~Observer()115     virtual ~Observer() {}
116   };
117 
118   SSLConfigService();
119 
120   // Create an instance of SSLConfigService which retrieves the configuration
121   // from the system SSL configuration, or an instance of
122   // SSLConfigServiceDefaults if the current system does not have a system SSL
123   // configuration.  Note: this does not handle SSLConfigService implementations
124   // that are not native to their platform, such as preference-backed ones.
125   static SSLConfigService* CreateSystemSSLConfigService();
126 
127   // May not be thread-safe, should only be called on the IO thread.
128   virtual void GetSSLConfig(SSLConfig* config) = 0;
129 
130   // Returns true if the given hostname is known to be incompatible with TLS
131   // False Start.
132   static bool IsKnownFalseStartIncompatibleServer(const std::string& hostname);
133 
134   // Enables the acceptance of self-signed certificates which contain an
135   // embedded DNSSEC chain proving their validity.
136   static void EnableDNSSEC();
137   static bool dnssec_enabled();
138 
139   // Disables False Start in SSL connections.
140   static void DisableFalseStart();
141   // True if we use False Start for SSL and TLS.
142   static bool false_start_enabled();
143 
144   // Enables DNS side checks for certificates.
145   static void EnableDNSCertProvenanceChecking();
146   static bool dns_cert_provenance_checking_enabled();
147 
148   // Add an observer of this service.
149   void AddObserver(Observer* observer);
150 
151   // Remove an observer of this service.
152   void RemoveObserver(Observer* observer);
153 
154  protected:
155   friend class base::RefCountedThreadSafe<SSLConfigService>;
156 
157   virtual ~SSLConfigService();
158 
159   // SetFlags sets the values of several flags based on global configuration.
160   static void SetSSLConfigFlags(SSLConfig* ssl_config);
161 
162   // Process before/after config update.
163   void ProcessConfigUpdate(const SSLConfig& orig_config,
164                            const SSLConfig& new_config);
165 
166  private:
167   ObserverList<Observer> observer_list_;
168 };
169 
170 }  // namespace net
171 
172 #endif  // NET_BASE_SSL_CONFIG_SERVICE_H_
173