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 // This has to come before SSL.
28 #include <folly/portability/Sockets.h>
30 #include <openssl/ssl.h>
31 #include <openssl/tls1.h>
33 #include <glog/logging.h>
35 #ifndef FOLLY_NO_CONFIG
36 #include <folly/folly-config.h>
39 #include <folly/Range.h>
40 #include <folly/io/async/ssl/OpenSSLPtrTypes.h>
41 #include <folly/io/async/ssl/OpenSSLUtils.h>
46 * Override the default password collector.
48 class PasswordCollector {
50 virtual ~PasswordCollector() = default;
52 * Interface for customizing how to collect private key password.
54 * By default, OpenSSL prints a prompt on screen and request for password
55 * while loading private key. To implement a custom password collector,
56 * implement this interface and register it with TSSLSocketFactory.
58 * @param password Pass collected password back to OpenSSL
59 * @param size Maximum length of password including nullptr character
61 virtual void getPassword(std::string& password, int size) = 0;
64 * Return a description of this collector for logging purposes
66 virtual std::string describe() const = 0;
70 * Wrap OpenSSL SSL_CTX into a class.
82 * Defines the way that peers are verified.
84 enum SSLVerifyPeerEnum {
85 // Used by AsyncSSLSocket to delegate to the SSLContext's setting
87 // For server side - request a client certificate and verify the
88 // certificate if it is sent. Does not fail if the client does not present
90 // For client side - validates the server certificate or fails.
92 // For server side - same as VERIFY but will fail if no certificate
94 // For client side - same as VERIFY.
95 VERIFY_REQ_CLIENT_CERT,
96 // No verification is done for both server and client side.
100 struct NextProtocolsItem {
101 NextProtocolsItem(int wt, const std::list<std::string>& ptcls):
102 weight(wt), protocols(ptcls) {}
104 std::list<std::string> protocols;
107 // Function that selects a client protocol given the server's list
108 using ClientProtocolFilterCallback = bool (*)(unsigned char**, unsigned int*,
109 const unsigned char*, unsigned int);
112 * Convenience function to call getErrors() with the current errno value.
114 * Make sure that you only call this when there was no intervening operation
115 * since the last OpenSSL error that may have changed the current errno value.
117 static std::string getErrors() {
118 return getErrors(errno);
124 * @param version The lowest or oldest SSL version to support.
126 explicit SSLContext(SSLVersion version = TLSv1);
127 virtual ~SSLContext();
130 * Set default ciphers to be used in SSL handshake process.
132 * @param ciphers A list of ciphers to use for TLSv1.0
134 virtual void ciphers(const std::string& ciphers);
137 * Low-level method that attempts to set the provided ciphers on the
138 * SSL_CTX object, and throws if something goes wrong.
140 virtual void setCiphersOrThrow(const std::string& ciphers);
143 * Method to set verification option in the context object.
145 * @param verifyPeer SSLVerifyPeerEnum indicating the verification
148 virtual void setVerificationOption(const SSLVerifyPeerEnum& verifyPeer);
151 * Method to check if peer verfication is set.
153 * @return true if peer verification is required.
156 virtual bool needsPeerVerification() {
157 return (verifyPeer_ == SSLVerifyPeerEnum::VERIFY ||
158 verifyPeer_ == SSLVerifyPeerEnum::VERIFY_REQ_CLIENT_CERT);
162 * Method to fetch Verification mode for a SSLVerifyPeerEnum.
163 * verifyPeer cannot be SSLVerifyPeerEnum::USE_CTX since there is no
166 * @param verifyPeer SSLVerifyPeerEnum for which the flags need to
169 * @return mode flags that can be used with SSL_set_verify
171 static int getVerificationMode(const SSLVerifyPeerEnum& verifyPeer);
174 * Method to fetch Verification mode determined by the options
175 * set using setVerificationOption.
177 * @return mode flags that can be used with SSL_set_verify
179 virtual int getVerificationMode();
182 * Enable/Disable authentication. Peer name validation can only be done
183 * if checkPeerCert is true.
185 * @param checkPeerCert If true, require peer to present valid certificate
186 * @param checkPeerName If true, validate that the certificate common name
187 * or alternate name(s) of peer matches the hostname
189 * @param peerName If non-empty, validate that the certificate common
190 * name of peer matches the given string (altername
191 * name(s) are not used in this case).
193 virtual void authenticate(bool checkPeerCert, bool checkPeerName,
194 const std::string& peerName = std::string());
196 * Load server certificate.
198 * @param path Path to the certificate file
199 * @param format Certificate file format
201 virtual void loadCertificate(const char* path, const char* format = "PEM");
203 * Load server certificate from memory.
205 * @param cert A PEM formatted certificate
207 virtual void loadCertificateFromBufferPEM(folly::StringPiece cert);
211 * @param path Path to the private key file
212 * @param format Private key file format
214 virtual void loadPrivateKey(const char* path, const char* format = "PEM");
216 * Load private key from memory.
218 * @param pkey A PEM formatted key
220 virtual void loadPrivateKeyFromBufferPEM(folly::StringPiece pkey);
222 * Load trusted certificates from specified file.
224 * @param path Path to trusted certificate file
226 virtual void loadTrustedCertificates(const char* path);
228 * Load trusted certificates from specified X509 certificate store.
230 * @param store X509 certificate store.
232 virtual void loadTrustedCertificates(X509_STORE* store);
234 * Load a client CA list for validating clients
236 virtual void loadClientCAList(const char* path);
238 * Override default OpenSSL password collector.
240 * @param collector Instance of user defined password collector
242 virtual void passwordCollector(std::shared_ptr<PasswordCollector> collector);
244 * Obtain password collector.
246 * @return User defined password collector
248 virtual std::shared_ptr<PasswordCollector> passwordCollector() {
251 #if OPENSSL_VERSION_NUMBER >= 0x1000105fL && !defined(OPENSSL_NO_TLSEXT)
253 * Provide SNI support
255 enum ServerNameCallbackResult {
257 SERVER_NAME_NOT_FOUND,
258 SERVER_NAME_NOT_FOUND_ALERT_FATAL,
261 * Callback function from openssl to give the application a
262 * chance to check the tlsext_hostname just right after parsing
263 * the Client Hello or Server Hello message.
265 * It is for the server to switch the SSL to another SSL_CTX
266 * to continue the handshake. (i.e. Server Name Indication, SNI, in RFC6066).
268 * If the ServerNameCallback returns:
270 * server: Send a tlsext_hostname in the Server Hello
272 * SERVER_NAME_NOT_FOUND:
273 * server: Does not send a tlsext_hostname in Server Hello
274 * and continue the handshake.
276 * SERVER_NAME_NOT_FOUND_ALERT_FATAL:
277 * server and client: Send fatal TLS1_AD_UNRECOGNIZED_NAME alert to
280 * Quote from RFC 6066:
282 * If the server understood the ClientHello extension but
283 * does not recognize the server name, the server SHOULD take one of two
284 * actions: either abort the handshake by sending a fatal-level
285 * unrecognized_name(112) alert or continue the handshake. It is NOT
286 * RECOMMENDED to send a warning-level unrecognized_name(112) alert,
287 * because the client's behavior in response to warning-level alerts is
293 * Set the ServerNameCallback
295 typedef std::function<ServerNameCallbackResult(SSL* ssl)> ServerNameCallback;
296 virtual void setServerNameCallback(const ServerNameCallback& cb);
299 * Generic callbacks that are run after we get the Client Hello (right
300 * before we run the ServerNameCallback)
302 typedef std::function<void(SSL* ssl)> ClientHelloCallback;
303 virtual void addClientHelloCallback(const ClientHelloCallback& cb);
307 * Create an SSL object from this context.
309 SSL* createSSL() const;
312 * Sets the namespace to use for sessions created from this context.
314 void setSessionCacheContext(const std::string& context);
317 * Set the options on the SSL_CTX object.
319 void setOptions(long options);
321 enum class NextProtocolType : uint8_t {
327 #ifdef OPENSSL_NPN_NEGOTIATED
329 * Set the list of protocols that this SSL context supports. In server
330 * mode, this is the list of protocols that will be advertised for Next
331 * Protocol Negotiation (NPN) or Application Layer Protocol Negotiation
332 * (ALPN). In client mode, the first protocol advertised by the server
333 * that is also on this list is chosen. Invoking this function with a list
334 * of length zero causes NPN to be disabled.
336 * @param protocols List of protocol names. This method makes a copy,
337 * so the caller needn't keep the list in scope after
338 * the call completes. The list must have at least
339 * one element to enable NPN. Each element must have
340 * a string length < 256.
341 * @param protocolType What type of protocol negotiation to support.
342 * @return true if NPN/ALPN has been activated. False if NPN/ALPN is disabled.
344 bool setAdvertisedNextProtocols(
345 const std::list<std::string>& protocols,
346 NextProtocolType protocolType = NextProtocolType::ANY);
348 * Set weighted list of lists of protocols that this SSL context supports.
349 * In server mode, each element of the list contains a list of protocols that
350 * could be advertised for Next Protocol Negotiation (NPN) or Application
351 * Layer Protocol Negotiation (ALPN). The list of protocols that will be
352 * advertised to a client is selected randomly, based on weights of elements.
353 * Client mode doesn't support randomized NPN/ALPN, so this list should
354 * contain only 1 element. The first protocol advertised by the server that
355 * is also on the list of protocols of this element is chosen. Invoking this
356 * function with a list of length zero causes NPN/ALPN to be disabled.
358 * @param items List of NextProtocolsItems, Each item contains a list of
359 * protocol names and weight. After the call of this fucntion
360 * each non-empty list of protocols will be advertised with
361 * probability weight/sum_of_weights. This method makes a copy,
362 * so the caller needn't keep the list in scope after the call
363 * completes. The list must have at least one element with
364 * non-zero weight and non-empty protocols list to enable NPN.
365 * Each name of the protocol must have a string length < 256.
366 * @param protocolType What type of protocol negotiation to support.
367 * @return true if NPN/ALPN has been activated. False if NPN/ALPN is disabled.
369 bool setRandomizedAdvertisedNextProtocols(
370 const std::list<NextProtocolsItem>& items,
371 NextProtocolType protocolType = NextProtocolType::ANY);
373 void setClientProtocolFilterCallback(ClientProtocolFilterCallback cb) {
374 clientProtoFilter_ = cb;
377 ClientProtocolFilterCallback getClientProtocolFilterCallback() {
378 return clientProtoFilter_;
382 * Disables NPN on this SSL context.
384 void unsetNextProtocols();
385 void deleteNextProtocolsStrings();
386 #endif // OPENSSL_NPN_NEGOTIATED
389 * Gets the underlying SSL_CTX for advanced usage
391 SSL_CTX *getSSLCtx() const {
402 * Set preferences for how to treat locks in OpenSSL. This must be
403 * called before the instantiation of any SSLContext objects, otherwise
404 * the defaults will be used.
406 * OpenSSL has a lock for each module rather than for each object or
407 * data that needs locking. Some locks protect only refcounts, and
408 * might be better as spinlocks rather than mutexes. Other locks
409 * may be totally unnecessary if the objects being protected are not
410 * shared between threads in the application.
412 * By default, all locks are initialized as mutexes. OpenSSL's lock usage
413 * may change from version to version and you should know what you are doing
414 * before disabling any locks entirely.
416 * Example: if you don't share SSL sessions between threads in your
417 * application, you may be able to do this
419 * setSSLLockTypes({{CRYPTO_LOCK_SSL_SESSION, SSLContext::LOCK_NONE}})
421 static void setSSLLockTypes(std::map<int, SSLLockType> lockTypes);
424 * Examine OpenSSL's error stack, and return a string description of the
427 * This operation removes the errors from OpenSSL's error stack.
429 static std::string getErrors(int errnoCopy);
432 * We want to vary which cipher we'll use based on the client's TLS version.
434 * XXX: The refernces to tls11CipherString and tls11AltCipherlist are reused
435 * for * each >= TLS 1.1 handshake, so we expect these fields to not change.
437 void switchCiphersIfTLS11(
439 const std::string& tls11CipherString,
440 const std::vector<std::pair<std::string, int>>& tls11AltCipherlist);
442 bool checkPeerName() { return checkPeerName_; }
443 std::string peerFixedName() { return peerFixedName_; }
445 #if defined(SSL_MODE_HANDSHAKE_CUTTHROUGH)
447 * Enable TLS false start, saving a roundtrip for full handshakes. Will only
448 * be used if the server uses NPN or ALPN, and a strong forward-secure cipher
451 void enableFalseStart();
455 * Helper to match a hostname versus a pattern.
457 static bool matchName(const char* host, const char* pattern, int size);
460 * Functions for setting up and cleaning up openssl.
461 * They can be invoked during the start of the application.
463 static void initializeOpenSSL();
464 static void cleanupOpenSSL();
467 * Mark openssl as initialized without actually performing any initialization.
468 * Please use this only if you are using a library which requires that it must
469 * make its own calls to SSL_library_init() and related functions.
471 static void markInitialized();
474 * Default randomize method.
476 static void randomize();
482 SSLVerifyPeerEnum verifyPeer_{SSLVerifyPeerEnum::NO_VERIFY};
485 std::string peerFixedName_;
486 std::shared_ptr<PasswordCollector> collector_;
487 #if OPENSSL_VERSION_NUMBER >= 0x1000105fL && !defined(OPENSSL_NO_TLSEXT)
488 ServerNameCallback serverNameCb_;
489 std::vector<ClientHelloCallback> clientHelloCbs_;
492 ClientProtocolFilterCallback clientProtoFilter_{nullptr};
494 static bool initialized_;
496 // To provide control over choice of server ciphersuites
497 std::unique_ptr<std::discrete_distribution<int>> cipherListPicker_;
499 #ifdef OPENSSL_NPN_NEGOTIATED
501 struct AdvertisedNextProtocolsItem {
502 unsigned char* protocols;
507 * Wire-format list of advertised protocols for use in NPN.
509 std::vector<AdvertisedNextProtocolsItem> advertisedNextProtocols_;
510 std::vector<int> advertisedNextProtocolWeights_;
511 std::discrete_distribution<int> nextProtocolDistribution_;
513 static int sNextProtocolsExDataIndex_;
515 static int advertisedNextProtocolCallback(SSL* ssl,
516 const unsigned char** out, unsigned int* outlen, void* data);
517 static int selectNextProtocolCallback(
518 SSL* ssl, unsigned char **out, unsigned char *outlen,
519 const unsigned char *server, unsigned int server_len, void *args);
521 #if OPENSSL_VERSION_NUMBER >= 0x1000200fL && !defined(OPENSSL_NO_TLSEXT)
522 static int alpnSelectCallback(SSL* ssl,
523 const unsigned char** out,
524 unsigned char* outlen,
525 const unsigned char* in,
529 size_t pickNextProtocols();
531 #endif // OPENSSL_NPN_NEGOTIATED
533 static int passwordCallback(char* password, int size, int, void* data);
535 #if OPENSSL_VERSION_NUMBER >= 0x1000105fL && !defined(OPENSSL_NO_TLSEXT)
537 * The function that will be called directly from openssl
538 * in order for the application to get the tlsext_hostname just after
539 * parsing the Client Hello or Server Hello message. It will then call
540 * the serverNameCb_ function object. Hence, it is sort of a
541 * wrapper/proxy between serverNameCb_ and openssl.
543 * The openssl's primary intention is for SNI support, but we also use it
544 * generically for performing logic after the Client Hello comes in.
546 static int baseServerNameOpenSSLCallback(
548 int* al /* alert (return value) */,
553 std::string providedCiphersString_;
555 // Functions are called when locked by the calling function.
556 static void initializeOpenSSLLocked();
557 static void cleanupOpenSSLLocked();
560 typedef std::shared_ptr<SSLContext> SSLContextPtr;
562 std::ostream& operator<<(std::ostream& os, const folly::PasswordCollector& collector);