2 * Copyright 2016 Facebook, Inc.
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
27 #include <openssl/ssl.h>
28 #include <openssl/tls1.h>
30 #include <sys/socket.h>
31 #include <netinet/in.h>
33 #include <glog/logging.h>
35 #ifndef FOLLY_NO_CONFIG
36 #include <folly/folly-config.h>
39 #include <folly/Random.h>
40 #include <folly/Range.h>
41 #include <folly/io/async/ssl/OpenSSLPtrTypes.h>
42 #include <folly/io/async/ssl/OpenSSLUtils.h>
47 * Override the default password collector.
49 class PasswordCollector {
51 virtual ~PasswordCollector() = default;
53 * Interface for customizing how to collect private key password.
55 * By default, OpenSSL prints a prompt on screen and request for password
56 * while loading private key. To implement a custom password collector,
57 * implement this interface and register it with TSSLSocketFactory.
59 * @param password Pass collected password back to OpenSSL
60 * @param size Maximum length of password including nullptr character
62 virtual void getPassword(std::string& password, int size) = 0;
65 * Return a description of this collector for logging purposes
67 virtual std::string describe() const = 0;
71 * Wrap OpenSSL SSL_CTX into a class.
83 * Defines the way that peers are verified.
85 enum SSLVerifyPeerEnum {
86 // Used by AsyncSSLSocket to delegate to the SSLContext's setting
88 // For server side - request a client certificate and verify the
89 // certificate if it is sent. Does not fail if the client does not present
91 // For client side - validates the server certificate or fails.
93 // For server side - same as VERIFY but will fail if no certificate
95 // For client side - same as VERIFY.
96 VERIFY_REQ_CLIENT_CERT,
97 // No verification is done for both server and client side.
101 struct NextProtocolsItem {
102 NextProtocolsItem(int wt, const std::list<std::string>& ptcls):
103 weight(wt), protocols(ptcls) {}
105 std::list<std::string> protocols;
108 // Function that selects a client protocol given the server's list
109 using ClientProtocolFilterCallback = bool (*)(unsigned char**, unsigned int*,
110 const unsigned char*, unsigned int);
113 * Convenience function to call getErrors() with the current errno value.
115 * Make sure that you only call this when there was no intervening operation
116 * since the last OpenSSL error that may have changed the current errno value.
118 static std::string getErrors() {
119 return getErrors(errno);
125 * @param version The lowest or oldest SSL version to support.
127 explicit SSLContext(SSLVersion version = TLSv1);
128 virtual ~SSLContext();
131 * Set default ciphers to be used in SSL handshake process.
133 * @param ciphers A list of ciphers to use for TLSv1.0
135 virtual void ciphers(const std::string& ciphers);
138 * Low-level method that attempts to set the provided ciphers on the
139 * SSL_CTX object, and throws if something goes wrong.
141 virtual void setCiphersOrThrow(const std::string& ciphers);
144 * Method to set verification option in the context object.
146 * @param verifyPeer SSLVerifyPeerEnum indicating the verification
149 virtual void setVerificationOption(const SSLVerifyPeerEnum& verifyPeer);
152 * Method to check if peer verfication is set.
154 * @return true if peer verification is required.
157 virtual bool needsPeerVerification() {
158 return (verifyPeer_ == SSLVerifyPeerEnum::VERIFY ||
159 verifyPeer_ == SSLVerifyPeerEnum::VERIFY_REQ_CLIENT_CERT);
163 * Method to fetch Verification mode for a SSLVerifyPeerEnum.
164 * verifyPeer cannot be SSLVerifyPeerEnum::USE_CTX since there is no
167 * @param verifyPeer SSLVerifyPeerEnum for which the flags need to
170 * @return mode flags that can be used with SSL_set_verify
172 static int getVerificationMode(const SSLVerifyPeerEnum& verifyPeer);
175 * Method to fetch Verification mode determined by the options
176 * set using setVerificationOption.
178 * @return mode flags that can be used with SSL_set_verify
180 virtual int getVerificationMode();
183 * Enable/Disable authentication. Peer name validation can only be done
184 * if checkPeerCert is true.
186 * @param checkPeerCert If true, require peer to present valid certificate
187 * @param checkPeerName If true, validate that the certificate common name
188 * or alternate name(s) of peer matches the hostname
190 * @param peerName If non-empty, validate that the certificate common
191 * name of peer matches the given string (altername
192 * name(s) are not used in this case).
194 virtual void authenticate(bool checkPeerCert, bool checkPeerName,
195 const std::string& peerName = std::string());
197 * Load server certificate.
199 * @param path Path to the certificate file
200 * @param format Certificate file format
202 virtual void loadCertificate(const char* path, const char* format = "PEM");
204 * Load server certificate from memory.
206 * @param cert A PEM formatted certificate
208 virtual void loadCertificateFromBufferPEM(folly::StringPiece cert);
212 * @param path Path to the private key file
213 * @param format Private key file format
215 virtual void loadPrivateKey(const char* path, const char* format = "PEM");
217 * Load private key from memory.
219 * @param pkey A PEM formatted key
221 virtual void loadPrivateKeyFromBufferPEM(folly::StringPiece pkey);
223 * Load trusted certificates from specified file.
225 * @param path Path to trusted certificate file
227 virtual void loadTrustedCertificates(const char* path);
229 * Load trusted certificates from specified X509 certificate store.
231 * @param store X509 certificate store.
233 virtual void loadTrustedCertificates(X509_STORE* store);
235 * Load a client CA list for validating clients
237 virtual void loadClientCAList(const char* path);
239 * Override default OpenSSL password collector.
241 * @param collector Instance of user defined password collector
243 virtual void passwordCollector(std::shared_ptr<PasswordCollector> collector);
245 * Obtain password collector.
247 * @return User defined password collector
249 virtual std::shared_ptr<PasswordCollector> passwordCollector() {
252 #if OPENSSL_VERSION_NUMBER >= 0x1000105fL && !defined(OPENSSL_NO_TLSEXT)
254 * Provide SNI support
256 enum ServerNameCallbackResult {
258 SERVER_NAME_NOT_FOUND,
259 SERVER_NAME_NOT_FOUND_ALERT_FATAL,
262 * Callback function from openssl to give the application a
263 * chance to check the tlsext_hostname just right after parsing
264 * the Client Hello or Server Hello message.
266 * It is for the server to switch the SSL to another SSL_CTX
267 * to continue the handshake. (i.e. Server Name Indication, SNI, in RFC6066).
269 * If the ServerNameCallback returns:
271 * server: Send a tlsext_hostname in the Server Hello
273 * SERVER_NAME_NOT_FOUND:
274 * server: Does not send a tlsext_hostname in Server Hello
275 * and continue the handshake.
277 * SERVER_NAME_NOT_FOUND_ALERT_FATAL:
278 * server and client: Send fatal TLS1_AD_UNRECOGNIZED_NAME alert to
281 * Quote from RFC 6066:
283 * If the server understood the ClientHello extension but
284 * does not recognize the server name, the server SHOULD take one of two
285 * actions: either abort the handshake by sending a fatal-level
286 * unrecognized_name(112) alert or continue the handshake. It is NOT
287 * RECOMMENDED to send a warning-level unrecognized_name(112) alert,
288 * because the client's behavior in response to warning-level alerts is
294 * Set the ServerNameCallback
296 typedef std::function<ServerNameCallbackResult(SSL* ssl)> ServerNameCallback;
297 virtual void setServerNameCallback(const ServerNameCallback& cb);
300 * Generic callbacks that are run after we get the Client Hello (right
301 * before we run the ServerNameCallback)
303 typedef std::function<void(SSL* ssl)> ClientHelloCallback;
304 virtual void addClientHelloCallback(const ClientHelloCallback& cb);
308 * Create an SSL object from this context.
310 SSL* createSSL() const;
313 * Set the options on the SSL_CTX object.
315 void setOptions(long options);
317 enum class NextProtocolType : uint8_t {
323 #ifdef OPENSSL_NPN_NEGOTIATED
325 * Set the list of protocols that this SSL context supports. In server
326 * mode, this is the list of protocols that will be advertised for Next
327 * Protocol Negotiation (NPN) or Application Layer Protocol Negotiation
328 * (ALPN). In client mode, the first protocol advertised by the server
329 * that is also on this list is chosen. Invoking this function with a list
330 * of length zero causes NPN to be disabled.
332 * @param protocols List of protocol names. This method makes a copy,
333 * so the caller needn't keep the list in scope after
334 * the call completes. The list must have at least
335 * one element to enable NPN. Each element must have
336 * a string length < 256.
337 * @param protocolType What type of protocol negotiation to support.
338 * @return true if NPN/ALPN has been activated. False if NPN/ALPN is disabled.
340 bool setAdvertisedNextProtocols(
341 const std::list<std::string>& protocols,
342 NextProtocolType protocolType = NextProtocolType::ANY);
344 * Set weighted list of lists of protocols that this SSL context supports.
345 * In server mode, each element of the list contains a list of protocols that
346 * could be advertised for Next Protocol Negotiation (NPN) or Application
347 * Layer Protocol Negotiation (ALPN). The list of protocols that will be
348 * advertised to a client is selected randomly, based on weights of elements.
349 * Client mode doesn't support randomized NPN/ALPN, so this list should
350 * contain only 1 element. The first protocol advertised by the server that
351 * is also on the list of protocols of this element is chosen. Invoking this
352 * function with a list of length zero causes NPN/ALPN to be disabled.
354 * @param items List of NextProtocolsItems, Each item contains a list of
355 * protocol names and weight. After the call of this fucntion
356 * each non-empty list of protocols will be advertised with
357 * probability weight/sum_of_weights. This method makes a copy,
358 * so the caller needn't keep the list in scope after the call
359 * completes. The list must have at least one element with
360 * non-zero weight and non-empty protocols list to enable NPN.
361 * Each name of the protocol must have a string length < 256.
362 * @param protocolType What type of protocol negotiation to support.
363 * @return true if NPN/ALPN has been activated. False if NPN/ALPN is disabled.
365 bool setRandomizedAdvertisedNextProtocols(
366 const std::list<NextProtocolsItem>& items,
367 NextProtocolType protocolType = NextProtocolType::ANY);
369 void setClientProtocolFilterCallback(ClientProtocolFilterCallback cb) {
370 clientProtoFilter_ = cb;
373 ClientProtocolFilterCallback getClientProtocolFilterCallback() {
374 return clientProtoFilter_;
377 * Disables NPN on this SSL context.
379 void unsetNextProtocols();
380 void deleteNextProtocolsStrings();
381 #endif // OPENSSL_NPN_NEGOTIATED
384 * Gets the underlying SSL_CTX for advanced usage
386 SSL_CTX *getSSLCtx() const {
397 * Set preferences for how to treat locks in OpenSSL. This must be
398 * called before the instantiation of any SSLContext objects, otherwise
399 * the defaults will be used.
401 * OpenSSL has a lock for each module rather than for each object or
402 * data that needs locking. Some locks protect only refcounts, and
403 * might be better as spinlocks rather than mutexes. Other locks
404 * may be totally unnecessary if the objects being protected are not
405 * shared between threads in the application.
407 * By default, all locks are initialized as mutexes. OpenSSL's lock usage
408 * may change from version to version and you should know what you are doing
409 * before disabling any locks entirely.
411 * Example: if you don't share SSL sessions between threads in your
412 * application, you may be able to do this
414 * setSSLLockTypes({{CRYPTO_LOCK_SSL_SESSION, SSLContext::LOCK_NONE}})
416 static void setSSLLockTypes(std::map<int, SSLLockType> lockTypes);
419 * Examine OpenSSL's error stack, and return a string description of the
422 * This operation removes the errors from OpenSSL's error stack.
424 static std::string getErrors(int errnoCopy);
427 * We want to vary which cipher we'll use based on the client's TLS version.
429 void switchCiphersIfTLS11(
431 const std::string& tls11CipherString
434 bool checkPeerName() { return checkPeerName_; }
435 std::string peerFixedName() { return peerFixedName_; }
437 #if defined(SSL_MODE_HANDSHAKE_CUTTHROUGH)
439 * Enable TLS false start, saving a roundtrip for full handshakes. Will only
440 * be used if the server uses NPN or ALPN, and a strong forward-secure cipher
443 void enableFalseStart();
447 * Helper to match a hostname versus a pattern.
449 static bool matchName(const char* host, const char* pattern, int size);
452 * Functions for setting up and cleaning up openssl.
453 * They can be invoked during the start of the application.
455 static void initializeOpenSSL();
456 static void cleanupOpenSSL();
459 * Mark openssl as initialized without actually performing any initialization.
460 * Please use this only if you are using a library which requires that it must
461 * make its own calls to SSL_library_init() and related functions.
463 static void markInitialized();
466 * Default randomize method.
468 static void randomize();
474 SSLVerifyPeerEnum verifyPeer_{SSLVerifyPeerEnum::NO_VERIFY};
477 std::string peerFixedName_;
478 std::shared_ptr<PasswordCollector> collector_;
479 #if OPENSSL_VERSION_NUMBER >= 0x1000105fL && !defined(OPENSSL_NO_TLSEXT)
480 ServerNameCallback serverNameCb_;
481 std::vector<ClientHelloCallback> clientHelloCbs_;
484 ClientProtocolFilterCallback clientProtoFilter_{nullptr};
486 static bool initialized_;
488 #ifdef OPENSSL_NPN_NEGOTIATED
490 struct AdvertisedNextProtocolsItem {
491 unsigned char* protocols;
496 * Wire-format list of advertised protocols for use in NPN.
498 std::vector<AdvertisedNextProtocolsItem> advertisedNextProtocols_;
499 std::vector<int> advertisedNextProtocolWeights_;
500 std::discrete_distribution<int> nextProtocolDistribution_;
501 Random::DefaultGenerator nextProtocolPicker_;
503 static int sNextProtocolsExDataIndex_;
505 static int advertisedNextProtocolCallback(SSL* ssl,
506 const unsigned char** out, unsigned int* outlen, void* data);
507 static int selectNextProtocolCallback(
508 SSL* ssl, unsigned char **out, unsigned char *outlen,
509 const unsigned char *server, unsigned int server_len, void *args);
511 #if OPENSSL_VERSION_NUMBER >= 0x1000200fL && !defined(OPENSSL_NO_TLSEXT)
512 static int alpnSelectCallback(SSL* ssl,
513 const unsigned char** out,
514 unsigned char* outlen,
515 const unsigned char* in,
519 size_t pickNextProtocols();
521 #endif // OPENSSL_NPN_NEGOTIATED
523 static int passwordCallback(char* password, int size, int, void* data);
525 #if OPENSSL_VERSION_NUMBER >= 0x1000105fL && !defined(OPENSSL_NO_TLSEXT)
527 * The function that will be called directly from openssl
528 * in order for the application to get the tlsext_hostname just after
529 * parsing the Client Hello or Server Hello message. It will then call
530 * the serverNameCb_ function object. Hence, it is sort of a
531 * wrapper/proxy between serverNameCb_ and openssl.
533 * The openssl's primary intention is for SNI support, but we also use it
534 * generically for performing logic after the Client Hello comes in.
536 static int baseServerNameOpenSSLCallback(
538 int* al /* alert (return value) */,
543 std::string providedCiphersString_;
545 // Functions are called when locked by the calling function.
546 static void initializeOpenSSLLocked();
547 static void cleanupOpenSSLLocked();
550 typedef std::shared_ptr<SSLContext> SSLContextPtr;
552 std::ostream& operator<<(std::ostream& os, const folly::PasswordCollector& collector);