1aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// 2aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// Copyright (C) 2011 The Android Open Source Project 3aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// 4aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// Licensed under the Apache License, Version 2.0 (the "License"); 5aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// you may not use this file except in compliance with the License. 6aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// You may obtain a copy of the License at 7aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// 8aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// http://www.apache.org/licenses/LICENSE-2.0 9aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// 10aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// Unless required by applicable law or agreed to in writing, software 11aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// distributed under the License is distributed on an "AS IS" BASIS, 12aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// See the License for the specific language governing permissions and 14aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// limitations under the License. 15aea4c1cea20dda7ae7e85fc8924a2d784f70d806Alex Deymo// 167f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 1714c0da88a93aa7b1aa71d5e7e923b537f0d419f3Alex Deymo#ifndef UPDATE_ENGINE_CERTIFICATE_CHECKER_H_ 1814c0da88a93aa7b1aa71d5e7e923b537f0d419f3Alex Deymo#define UPDATE_ENGINE_CERTIFICATE_CHECKER_H_ 197f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 2005735a1879a553153458aae0a25fa5d42e3e408fBen Chan#include <curl/curl.h> 2105735a1879a553153458aae0a25fa5d42e3e408fBen Chan#include <openssl/ssl.h> 2205735a1879a553153458aae0a25fa5d42e3e408fBen Chan 237f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha#include <string> 247f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 2505735a1879a553153458aae0a25fa5d42e3e408fBen Chan#include <base/macros.h> 267f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha#include <gtest/gtest_prod.h> // for FRIEND_TEST 277f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 287f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rochanamespace chromeos_update_engine { 297f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 30c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymoclass PrefsInterface; 31c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo 327f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha// Wrapper for openssl operations with the certificates. 337f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rochaclass OpenSSLWrapper { 347f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha public: 35c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo OpenSSLWrapper() = default; 36c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo virtual ~OpenSSLWrapper() = default; 377f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 387f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // Takes an openssl X509_STORE_CTX, extracts the corresponding certificate 397f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // from it and calculates its fingerprint (SHA256 digest). Returns true on 407f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // success and false otherwise. 417f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // 427f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // |x509_ctx| is the pointer to the openssl object that holds the certificate. 437f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // |out_depth| is the depth of the current certificate, in the certificate 447f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // chain. 457f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // |out_digest_length| is the length of the generated digest. 467f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // |out_digest| is the byte array where the digest itself will be written. 477f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // It should be big enough to hold a SHA1 digest (e.g. EVP_MAX_MD_SIZE). 487f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha virtual bool GetCertificateDigest(X509_STORE_CTX* x509_ctx, 497f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha int* out_depth, 507f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha unsigned int* out_digest_length, 51f68bbbc952aa9a71898e4939b5f36187fa564a50Alex Vakulenko uint8_t* out_digest) const; 527f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 537f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha private: 547f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha DISALLOW_COPY_AND_ASSIGN(OpenSSLWrapper); 557f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha}; 567f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 57c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo// The values in this enum are replicated in the metrics server. See metrics.h 58c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo// for instructions on how to update these values in the server side. 59c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymoenum class CertificateCheckResult { 60c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // The certificate is valid and the same as seen before or the first time we 61c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // see a certificate. 62c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo kValid, 63c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // The certificate is valid, but is different than a previously seen 64c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // certificate for the selected server. 65c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo kValidChanged, 66c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // The certificate validation failed. 67c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo kFailed, 68c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo 69c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // This value must be the last entry. 70c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo kNumConstants 71c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo}; 72c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo 73c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo// These values are used to generate the keys of files persisted via prefs. 74c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo// This means that changing these will cause loss of information on metrics 75c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo// reporting, during the transition. These values are also mapped to a metric 76c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo// name in metrics.cc, so adding values here requires to assign a new metric 77c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo// name in that file. 78c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymoenum class ServerToCheck { 79c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo kUpdate = 0, 80c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo kDownload, 8133e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo 8233e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // Ignore this server. 8333e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo kNone, 84c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo}; 85c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo 867f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha// Responsible for checking whether update server certificates change, and 877f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha// reporting to UMA when this happens. Since all state information is persisted, 887f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha// and openssl forces us to use a static callback with no data pointer, this 897f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha// class is entirely static. 907f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rochaclass CertificateChecker { 917f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha public: 92c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo class Observer { 93c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo public: 94c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo virtual ~Observer() = default; 95c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo 96c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // Called whenever a certificate is checked for the server |server_to_check| 97c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // passing the result of said certificate check. 98c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo virtual void CertificateChecked(ServerToCheck server_to_check, 99c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo CertificateCheckResult result) = 0; 1007f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha }; 1017f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 10233e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo CertificateChecker(PrefsInterface* prefs, OpenSSLWrapper* openssl_wrapper); 10333e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo ~CertificateChecker(); 1047f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 1057f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // This callback is called by libcurl just before the initialization of an 1067f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // SSL connection after having processed all other SSL related options. Used 107c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // to check if server certificates change. |cert_checker| is expected to be a 108c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // pointer to the CertificateChecker instance. 109c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo static CURLcode ProcessSSLContext(CURL* curl_handle, 110c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo SSL_CTX* ssl_ctx, 111c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo void* cert_checker); 1127f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 11333e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // Initialize this class as the singleton instance. Only one instance can be 11433e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // initialized at a time and it should be initialized before other methods 11533e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // can be used. 11633e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo void Init(); 11733e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo 118c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // Set the certificate observer to the passed instance. To remove the 119c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // observer, pass a nullptr. The |observer| instance must be valid while this 120c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // CertificateChecker verifies certificates. 121c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo void SetObserver(Observer* observer) { observer_ = observer; } 1227f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 1237f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha private: 1247f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha FRIEND_TEST(CertificateCheckerTest, NewCertificate); 1257f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha FRIEND_TEST(CertificateCheckerTest, SameCertificate); 1267f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha FRIEND_TEST(CertificateCheckerTest, ChangedCertificate); 1277f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha FRIEND_TEST(CertificateCheckerTest, FailedCertificate); 1287f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 12933e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // These callbacks are asynchronously called by openssl after initial SSL 13033e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // verification. They are used to perform any additional security verification 13133e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // on the connection, but we use them here to get hold of the server 13233e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // certificate, in order to determine if it has changed since the last 13333e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // connection. Since openssl forces us to do this statically, we define two 13433e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // different callbacks for the two different official update servers, and only 13533e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // assign the correspondent one. The assigned callback is then called once per 136c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // each certificate on the server and returns 1 for success and 0 for failure. 13733e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo static int VerifySSLCallbackDownload(int preverify_ok, 13833e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo X509_STORE_CTX* x509_ctx); 13933e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo static int VerifySSLCallbackUpdate(int preverify_ok, 14033e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo X509_STORE_CTX* x509_ctx); 14133e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo static int VerifySSLCallback(int preverify_ok, 14233e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo X509_STORE_CTX* x509_ctx, 14333e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo ServerToCheck server_to_check); 144c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo 145c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // Checks if server certificate stored in |x509_ctx| has changed since last 14633e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // connection to that same server, specified by |server_to_check|. 147c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // This is called by the callbacks defined above. The result of the 148c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // certificate check is passed to the observer, if any. Returns true on 149c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // success and false otherwise. 15033e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo bool CheckCertificateChange(int preverify_ok, 15133e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo X509_STORE_CTX* x509_ctx, 15233e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo ServerToCheck server_to_check); 153c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo 154c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // Notifies the observer, if any, of a certificate checking. 15533e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo void NotifyCertificateChecked(ServerToCheck server_to_check, 15633e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo CertificateCheckResult result); 15733e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo 15833e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo // The CertificateChecker singleton instance. 15933e91e78bfe98c063b0c3b6d590976e275685686Alex Deymo static CertificateChecker* cert_checker_singleton_; 160c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo 161c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // Prefs instance used to store the certificates seen in the past. 162c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo PrefsInterface* prefs_; 1637f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 1647f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha // The wrapper for openssl operations. 165c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo OpenSSLWrapper* openssl_wrapper_; 166c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo 167c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo // The observer called whenever a certificate is checked, if not null. 168c1c17b4ed6a3896b6343e737fd89682fa0c8436bAlex Deymo Observer* observer_{nullptr}; 1697f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 1707f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha DISALLOW_COPY_AND_ASSIGN(CertificateChecker); 1717f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha}; 1727f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 1737f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha} // namespace chromeos_update_engine 1747f9aea2748370b0a26e1d5c36db7d8bbf3ba1245Bruno Rocha 17514c0da88a93aa7b1aa71d5e7e923b537f0d419f3Alex Deymo#endif // UPDATE_ENGINE_CERTIFICATE_CHECKER_H_ 176