2 * Copyright 2017 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/OpenSSL.h>
29 #include <folly/portability/Sockets.h>
31 #include <openssl/ssl.h>
32 #include <openssl/tls1.h>
34 #include <glog/logging.h>
36 #ifndef FOLLY_NO_CONFIG
37 #include <folly/folly-config.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) const = 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 * Set default ciphers to be used in SSL handshake process.
140 * @param ciphers A list of ciphers to use for TLS.
142 virtual void setCipherList(const std::vector<std::string>& ciphers);
145 * Low-level method that attempts to set the provided ciphers on the
146 * SSL_CTX object, and throws if something goes wrong.
148 virtual void setCiphersOrThrow(const std::string& ciphers);
151 * Sets the signature algorithms to be used during SSL negotiation
154 * @param sigalgs A list of signature algorithms, eg. RSA+SHA512
156 void setSignatureAlgorithms(const std::vector<std::string>& sigalgs);
159 * Sets the list of EC curves supported by the client.
161 * @param ecCurves A list of ec curves, eg: P-256
163 void setClientECCurvesList(const std::vector<std::string>& ecCurves);
166 * Method to add support for a specific elliptic curve encryption algorithm.
168 * @param curveName: The name of the ec curve to support, eg: prime256v1.
170 void setServerECCurve(const std::string& curveName);
173 * Sets an x509 verification param on the context.
175 void setX509VerifyParam(const ssl::X509VerifyParam& x509VerifyParam);
178 * Method to set verification option in the context object.
180 * @param verifyPeer SSLVerifyPeerEnum indicating the verification
183 virtual void setVerificationOption(const SSLVerifyPeerEnum& verifyPeer);
186 * Method to check if peer verfication is set.
188 * @return true if peer verification is required.
191 virtual bool needsPeerVerification() {
192 return (verifyPeer_ == SSLVerifyPeerEnum::VERIFY ||
193 verifyPeer_ == SSLVerifyPeerEnum::VERIFY_REQ_CLIENT_CERT);
197 * Method to fetch Verification mode for a SSLVerifyPeerEnum.
198 * verifyPeer cannot be SSLVerifyPeerEnum::USE_CTX since there is no
201 * @param verifyPeer SSLVerifyPeerEnum for which the flags need to
204 * @return mode flags that can be used with SSL_set_verify
206 static int getVerificationMode(const SSLVerifyPeerEnum& verifyPeer);
209 * Method to fetch Verification mode determined by the options
210 * set using setVerificationOption.
212 * @return mode flags that can be used with SSL_set_verify
214 virtual int getVerificationMode();
217 * Enable/Disable authentication. Peer name validation can only be done
218 * if checkPeerCert is true.
220 * @param checkPeerCert If true, require peer to present valid certificate
221 * @param checkPeerName If true, validate that the certificate common name
222 * or alternate name(s) of peer matches the hostname
224 * @param peerName If non-empty, validate that the certificate common
225 * name of peer matches the given string (altername
226 * name(s) are not used in this case).
228 virtual void authenticate(bool checkPeerCert, bool checkPeerName,
229 const std::string& peerName = std::string());
231 * Load server certificate.
233 * @param path Path to the certificate file
234 * @param format Certificate file format
236 virtual void loadCertificate(const char* path, const char* format = "PEM");
238 * Load server certificate from memory.
240 * @param cert A PEM formatted certificate
242 virtual void loadCertificateFromBufferPEM(folly::StringPiece cert);
246 * @param path Path to the private key file
247 * @param format Private key file format
249 virtual void loadPrivateKey(const char* path, const char* format = "PEM");
251 * Load private key from memory.
253 * @param pkey A PEM formatted key
255 virtual void loadPrivateKeyFromBufferPEM(folly::StringPiece pkey);
257 * Load trusted certificates from specified file.
259 * @param path Path to trusted certificate file
261 virtual void loadTrustedCertificates(const char* path);
263 * Load trusted certificates from specified X509 certificate store.
265 * @param store X509 certificate store.
267 virtual void loadTrustedCertificates(X509_STORE* store);
269 * Load a client CA list for validating clients
271 virtual void loadClientCAList(const char* path);
273 * Override default OpenSSL password collector.
275 * @param collector Instance of user defined password collector
277 virtual void passwordCollector(std::shared_ptr<PasswordCollector> collector);
279 * Obtain password collector.
281 * @return User defined password collector
283 virtual std::shared_ptr<PasswordCollector> passwordCollector() {
286 #if FOLLY_OPENSSL_HAS_SNI
288 * Provide SNI support
290 enum ServerNameCallbackResult {
292 SERVER_NAME_NOT_FOUND,
293 SERVER_NAME_NOT_FOUND_ALERT_FATAL,
296 * Callback function from openssl to give the application a
297 * chance to check the tlsext_hostname just right after parsing
298 * the Client Hello or Server Hello message.
300 * It is for the server to switch the SSL to another SSL_CTX
301 * to continue the handshake. (i.e. Server Name Indication, SNI, in RFC6066).
303 * If the ServerNameCallback returns:
305 * server: Send a tlsext_hostname in the Server Hello
307 * SERVER_NAME_NOT_FOUND:
308 * server: Does not send a tlsext_hostname in Server Hello
309 * and continue the handshake.
311 * SERVER_NAME_NOT_FOUND_ALERT_FATAL:
312 * server and client: Send fatal TLS1_AD_UNRECOGNIZED_NAME alert to
315 * Quote from RFC 6066:
317 * If the server understood the ClientHello extension but
318 * does not recognize the server name, the server SHOULD take one of two
319 * actions: either abort the handshake by sending a fatal-level
320 * unrecognized_name(112) alert or continue the handshake. It is NOT
321 * RECOMMENDED to send a warning-level unrecognized_name(112) alert,
322 * because the client's behavior in response to warning-level alerts is
328 * Set the ServerNameCallback
330 typedef std::function<ServerNameCallbackResult(SSL* ssl)> ServerNameCallback;
331 virtual void setServerNameCallback(const ServerNameCallback& cb);
334 * Generic callbacks that are run after we get the Client Hello (right
335 * before we run the ServerNameCallback)
337 typedef std::function<void(SSL* ssl)> ClientHelloCallback;
338 virtual void addClientHelloCallback(const ClientHelloCallback& cb);
339 #endif // FOLLY_OPENSSL_HAS_SNI
342 * Create an SSL object from this context.
344 SSL* createSSL() const;
347 * Sets the namespace to use for sessions created from this context.
349 void setSessionCacheContext(const std::string& context);
352 * Set the options on the SSL_CTX object.
354 void setOptions(long options);
356 enum class NextProtocolType : uint8_t {
362 #ifdef OPENSSL_NPN_NEGOTIATED
364 * Set the list of protocols that this SSL context supports. In server
365 * mode, this is the list of protocols that will be advertised for Next
366 * Protocol Negotiation (NPN) or Application Layer Protocol Negotiation
367 * (ALPN). In client mode, the first protocol advertised by the server
368 * that is also on this list is chosen. Invoking this function with a list
369 * of length zero causes NPN to be disabled.
371 * @param protocols List of protocol names. This method makes a copy,
372 * so the caller needn't keep the list in scope after
373 * the call completes. The list must have at least
374 * one element to enable NPN. Each element must have
375 * a string length < 256.
376 * @param protocolType What type of protocol negotiation to support.
377 * @return true if NPN/ALPN has been activated. False if NPN/ALPN is disabled.
379 bool setAdvertisedNextProtocols(
380 const std::list<std::string>& protocols,
381 NextProtocolType protocolType = NextProtocolType::ANY);
383 * Set weighted list of lists of protocols that this SSL context supports.
384 * In server mode, each element of the list contains a list of protocols that
385 * could be advertised for Next Protocol Negotiation (NPN) or Application
386 * Layer Protocol Negotiation (ALPN). The list of protocols that will be
387 * advertised to a client is selected randomly, based on weights of elements.
388 * Client mode doesn't support randomized NPN/ALPN, so this list should
389 * contain only 1 element. The first protocol advertised by the server that
390 * is also on the list of protocols of this element is chosen. Invoking this
391 * function with a list of length zero causes NPN/ALPN to be disabled.
393 * @param items List of NextProtocolsItems, Each item contains a list of
394 * protocol names and weight. After the call of this fucntion
395 * each non-empty list of protocols will be advertised with
396 * probability weight/sum_of_weights. This method makes a copy,
397 * so the caller needn't keep the list in scope after the call
398 * completes. The list must have at least one element with
399 * non-zero weight and non-empty protocols list to enable NPN.
400 * Each name of the protocol must have a string length < 256.
401 * @param protocolType What type of protocol negotiation to support.
402 * @return true if NPN/ALPN has been activated. False if NPN/ALPN is disabled.
404 bool setRandomizedAdvertisedNextProtocols(
405 const std::list<NextProtocolsItem>& items,
406 NextProtocolType protocolType = NextProtocolType::ANY);
408 void setClientProtocolFilterCallback(ClientProtocolFilterCallback cb) {
409 clientProtoFilter_ = cb;
412 ClientProtocolFilterCallback getClientProtocolFilterCallback() {
413 return clientProtoFilter_;
417 * Disables NPN on this SSL context.
419 void unsetNextProtocols();
420 void deleteNextProtocolsStrings();
421 #endif // OPENSSL_NPN_NEGOTIATED
424 * Gets the underlying SSL_CTX for advanced usage
426 SSL_CTX *getSSLCtx() const {
437 * Set preferences for how to treat locks in OpenSSL. This must be
438 * called before the instantiation of any SSLContext objects, otherwise
439 * the defaults will be used.
441 * OpenSSL has a lock for each module rather than for each object or
442 * data that needs locking. Some locks protect only refcounts, and
443 * might be better as spinlocks rather than mutexes. Other locks
444 * may be totally unnecessary if the objects being protected are not
445 * shared between threads in the application.
447 * By default, all locks are initialized as mutexes. OpenSSL's lock usage
448 * may change from version to version and you should know what you are doing
449 * before disabling any locks entirely.
451 * Example: if you don't share SSL sessions between threads in your
452 * application, you may be able to do this
454 * setSSLLockTypes({{CRYPTO_LOCK_SSL_SESSION, SSLContext::LOCK_NONE}})
456 static void setSSLLockTypes(std::map<int, SSLLockType> lockTypes);
459 * Examine OpenSSL's error stack, and return a string description of the
462 * This operation removes the errors from OpenSSL's error stack.
464 static std::string getErrors(int errnoCopy);
467 * We want to vary which cipher we'll use based on the client's TLS version.
469 * XXX: The refernces to tls11CipherString and tls11AltCipherlist are reused
470 * for * each >= TLS 1.1 handshake, so we expect these fields to not change.
472 void switchCiphersIfTLS11(
474 const std::string& tls11CipherString,
475 const std::vector<std::pair<std::string, int>>& tls11AltCipherlist);
477 bool checkPeerName() { return checkPeerName_; }
478 std::string peerFixedName() { return peerFixedName_; }
480 #if defined(SSL_MODE_HANDSHAKE_CUTTHROUGH)
482 * Enable TLS false start, saving a roundtrip for full handshakes. Will only
483 * be used if the server uses NPN or ALPN, and a strong forward-secure cipher
486 void enableFalseStart();
490 * Helper to match a hostname versus a pattern.
492 static bool matchName(const char* host, const char* pattern, int size);
495 * Functions for setting up and cleaning up openssl.
496 * They can be invoked during the start of the application.
498 static void initializeOpenSSL();
499 static void cleanupOpenSSL();
502 * Mark openssl as initialized without actually performing any initialization.
503 * Please use this only if you are using a library which requires that it must
504 * make its own calls to SSL_library_init() and related functions.
506 static void markInitialized();
509 * Default randomize method.
511 static void randomize();
517 SSLVerifyPeerEnum verifyPeer_{SSLVerifyPeerEnum::NO_VERIFY};
520 std::string peerFixedName_;
521 std::shared_ptr<PasswordCollector> collector_;
522 #if FOLLY_OPENSSL_HAS_SNI
523 ServerNameCallback serverNameCb_;
524 std::vector<ClientHelloCallback> clientHelloCbs_;
527 ClientProtocolFilterCallback clientProtoFilter_{nullptr};
529 static bool initialized_;
531 // To provide control over choice of server ciphersuites
532 std::unique_ptr<std::discrete_distribution<int>> cipherListPicker_;
534 #ifdef OPENSSL_NPN_NEGOTIATED
536 struct AdvertisedNextProtocolsItem {
537 unsigned char* protocols;
542 * Wire-format list of advertised protocols for use in NPN.
544 std::vector<AdvertisedNextProtocolsItem> advertisedNextProtocols_;
545 std::vector<int> advertisedNextProtocolWeights_;
546 std::discrete_distribution<int> nextProtocolDistribution_;
548 static int sNextProtocolsExDataIndex_;
550 static int advertisedNextProtocolCallback(SSL* ssl,
551 const unsigned char** out, unsigned int* outlen, void* data);
552 static int selectNextProtocolCallback(
553 SSL* ssl, unsigned char **out, unsigned char *outlen,
554 const unsigned char *server, unsigned int server_len, void *args);
556 #if FOLLY_OPENSSL_HAS_ALPN
557 static int alpnSelectCallback(SSL* ssl,
558 const unsigned char** out,
559 unsigned char* outlen,
560 const unsigned char* in,
564 size_t pickNextProtocols();
566 #endif // OPENSSL_NPN_NEGOTIATED
568 static int passwordCallback(char* password, int size, int, void* data);
570 #if FOLLY_OPENSSL_HAS_SNI
572 * The function that will be called directly from openssl
573 * in order for the application to get the tlsext_hostname just after
574 * parsing the Client Hello or Server Hello message. It will then call
575 * the serverNameCb_ function object. Hence, it is sort of a
576 * wrapper/proxy between serverNameCb_ and openssl.
578 * The openssl's primary intention is for SNI support, but we also use it
579 * generically for performing logic after the Client Hello comes in.
581 static int baseServerNameOpenSSLCallback(
583 int* al /* alert (return value) */,
588 std::string providedCiphersString_;
590 // Functions are called when locked by the calling function.
591 static void initializeOpenSSLLocked();
592 static void cleanupOpenSSLLocked();
595 typedef std::shared_ptr<SSLContext> SSLContextPtr;
597 std::ostream& operator<<(std::ostream& os, const folly::PasswordCollector& collector);