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 * Sets the namespace to use for sessions created from this context.
315 void setSessionCacheContext(const std::string& context);
318 * Set the options on the SSL_CTX object.
320 void setOptions(long options);
322 enum class NextProtocolType : uint8_t {
328 #ifdef OPENSSL_NPN_NEGOTIATED
330 * Set the list of protocols that this SSL context supports. In server
331 * mode, this is the list of protocols that will be advertised for Next
332 * Protocol Negotiation (NPN) or Application Layer Protocol Negotiation
333 * (ALPN). In client mode, the first protocol advertised by the server
334 * that is also on this list is chosen. Invoking this function with a list
335 * of length zero causes NPN to be disabled.
337 * @param protocols List of protocol names. This method makes a copy,
338 * so the caller needn't keep the list in scope after
339 * the call completes. The list must have at least
340 * one element to enable NPN. Each element must have
341 * a string length < 256.
342 * @param protocolType What type of protocol negotiation to support.
343 * @return true if NPN/ALPN has been activated. False if NPN/ALPN is disabled.
345 bool setAdvertisedNextProtocols(
346 const std::list<std::string>& protocols,
347 NextProtocolType protocolType = NextProtocolType::ANY);
349 * Set weighted list of lists of protocols that this SSL context supports.
350 * In server mode, each element of the list contains a list of protocols that
351 * could be advertised for Next Protocol Negotiation (NPN) or Application
352 * Layer Protocol Negotiation (ALPN). The list of protocols that will be
353 * advertised to a client is selected randomly, based on weights of elements.
354 * Client mode doesn't support randomized NPN/ALPN, so this list should
355 * contain only 1 element. The first protocol advertised by the server that
356 * is also on the list of protocols of this element is chosen. Invoking this
357 * function with a list of length zero causes NPN/ALPN to be disabled.
359 * @param items List of NextProtocolsItems, Each item contains a list of
360 * protocol names and weight. After the call of this fucntion
361 * each non-empty list of protocols will be advertised with
362 * probability weight/sum_of_weights. This method makes a copy,
363 * so the caller needn't keep the list in scope after the call
364 * completes. The list must have at least one element with
365 * non-zero weight and non-empty protocols list to enable NPN.
366 * Each name of the protocol must have a string length < 256.
367 * @param protocolType What type of protocol negotiation to support.
368 * @return true if NPN/ALPN has been activated. False if NPN/ALPN is disabled.
370 bool setRandomizedAdvertisedNextProtocols(
371 const std::list<NextProtocolsItem>& items,
372 NextProtocolType protocolType = NextProtocolType::ANY);
374 void setClientProtocolFilterCallback(ClientProtocolFilterCallback cb) {
375 clientProtoFilter_ = cb;
378 ClientProtocolFilterCallback getClientProtocolFilterCallback() {
379 return clientProtoFilter_;
383 * Disables NPN on this SSL context.
385 void unsetNextProtocols();
386 void deleteNextProtocolsStrings();
387 #endif // OPENSSL_NPN_NEGOTIATED
390 * Gets the underlying SSL_CTX for advanced usage
392 SSL_CTX *getSSLCtx() const {
403 * Set preferences for how to treat locks in OpenSSL. This must be
404 * called before the instantiation of any SSLContext objects, otherwise
405 * the defaults will be used.
407 * OpenSSL has a lock for each module rather than for each object or
408 * data that needs locking. Some locks protect only refcounts, and
409 * might be better as spinlocks rather than mutexes. Other locks
410 * may be totally unnecessary if the objects being protected are not
411 * shared between threads in the application.
413 * By default, all locks are initialized as mutexes. OpenSSL's lock usage
414 * may change from version to version and you should know what you are doing
415 * before disabling any locks entirely.
417 * Example: if you don't share SSL sessions between threads in your
418 * application, you may be able to do this
420 * setSSLLockTypes({{CRYPTO_LOCK_SSL_SESSION, SSLContext::LOCK_NONE}})
422 static void setSSLLockTypes(std::map<int, SSLLockType> lockTypes);
425 * Examine OpenSSL's error stack, and return a string description of the
428 * This operation removes the errors from OpenSSL's error stack.
430 static std::string getErrors(int errnoCopy);
433 * We want to vary which cipher we'll use based on the client's TLS version.
435 void switchCiphersIfTLS11(
437 const std::string& tls11CipherString
440 bool checkPeerName() { return checkPeerName_; }
441 std::string peerFixedName() { return peerFixedName_; }
443 #if defined(SSL_MODE_HANDSHAKE_CUTTHROUGH)
445 * Enable TLS false start, saving a roundtrip for full handshakes. Will only
446 * be used if the server uses NPN or ALPN, and a strong forward-secure cipher
449 void enableFalseStart();
453 * Helper to match a hostname versus a pattern.
455 static bool matchName(const char* host, const char* pattern, int size);
458 * Functions for setting up and cleaning up openssl.
459 * They can be invoked during the start of the application.
461 static void initializeOpenSSL();
462 static void cleanupOpenSSL();
465 * Mark openssl as initialized without actually performing any initialization.
466 * Please use this only if you are using a library which requires that it must
467 * make its own calls to SSL_library_init() and related functions.
469 static void markInitialized();
472 * Default randomize method.
474 static void randomize();
480 SSLVerifyPeerEnum verifyPeer_{SSLVerifyPeerEnum::NO_VERIFY};
483 std::string peerFixedName_;
484 std::shared_ptr<PasswordCollector> collector_;
485 #if OPENSSL_VERSION_NUMBER >= 0x1000105fL && !defined(OPENSSL_NO_TLSEXT)
486 ServerNameCallback serverNameCb_;
487 std::vector<ClientHelloCallback> clientHelloCbs_;
490 ClientProtocolFilterCallback clientProtoFilter_{nullptr};
492 static bool initialized_;
494 #ifdef OPENSSL_NPN_NEGOTIATED
496 struct AdvertisedNextProtocolsItem {
497 unsigned char* protocols;
502 * Wire-format list of advertised protocols for use in NPN.
504 std::vector<AdvertisedNextProtocolsItem> advertisedNextProtocols_;
505 std::vector<int> advertisedNextProtocolWeights_;
506 std::discrete_distribution<int> nextProtocolDistribution_;
507 Random::DefaultGenerator nextProtocolPicker_;
509 static int sNextProtocolsExDataIndex_;
511 static int advertisedNextProtocolCallback(SSL* ssl,
512 const unsigned char** out, unsigned int* outlen, void* data);
513 static int selectNextProtocolCallback(
514 SSL* ssl, unsigned char **out, unsigned char *outlen,
515 const unsigned char *server, unsigned int server_len, void *args);
517 #if OPENSSL_VERSION_NUMBER >= 0x1000200fL && !defined(OPENSSL_NO_TLSEXT)
518 static int alpnSelectCallback(SSL* ssl,
519 const unsigned char** out,
520 unsigned char* outlen,
521 const unsigned char* in,
525 size_t pickNextProtocols();
527 #endif // OPENSSL_NPN_NEGOTIATED
529 static int passwordCallback(char* password, int size, int, void* data);
531 #if OPENSSL_VERSION_NUMBER >= 0x1000105fL && !defined(OPENSSL_NO_TLSEXT)
533 * The function that will be called directly from openssl
534 * in order for the application to get the tlsext_hostname just after
535 * parsing the Client Hello or Server Hello message. It will then call
536 * the serverNameCb_ function object. Hence, it is sort of a
537 * wrapper/proxy between serverNameCb_ and openssl.
539 * The openssl's primary intention is for SNI support, but we also use it
540 * generically for performing logic after the Client Hello comes in.
542 static int baseServerNameOpenSSLCallback(
544 int* al /* alert (return value) */,
549 std::string providedCiphersString_;
551 // Functions are called when locked by the calling function.
552 static void initializeOpenSSLLocked();
553 static void cleanupOpenSSLLocked();
556 typedef std::shared_ptr<SSLContext> SSLContextPtr;
558 std::ostream& operator<<(std::ostream& os, const folly::PasswordCollector& collector);