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/*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <list>
#include <map>
#include <memory>
#include <mutex>
#include <random>
#include <string>
#include <vector>
#include <glog/logging.h>
#ifndef FOLLY_NO_CONFIG
#include <folly/folly-config.h>
#endif
#include <folly/Function.h>
#include <folly/Portability.h>
#include <folly/Range.h>
#include <folly/String.h>
#include <folly/io/async/ssl/OpenSSLUtils.h>
#include <folly/portability/OpenSSL.h>
#include <folly/ssl/OpenSSLLockTypes.h>
#include <folly/ssl/OpenSSLPtrTypes.h>
namespace folly {
/**
* Override the default password collector.
*/
class PasswordCollector {
public:
virtual ~PasswordCollector() = default;
/**
* Interface for customizing how to collect private key password.
*
* By default, OpenSSL prints a prompt on screen and request for password
* while loading private key. To implement a custom password collector,
* implement this interface and register it with SSLContext.
*
* @param password Pass collected password back to OpenSSL
* @param size Maximum length of password including nullptr character
*/
virtual void getPassword(std::string& password, int size) const = 0;
/**
* Return a description of this collector for logging purposes
*/
virtual std::string describe() const = 0;
};
/**
* Run SSL_accept via a runner
*/
class SSLAcceptRunner {
public:
virtual ~SSLAcceptRunner() = default;
/**
* This is expected to run the first function and provide its return
* value to the second function. This can be used to run the SSL_accept
* in different contexts.
*/
virtual void run(Function<int()> acceptFunc, Function<void(int)> finallyFunc)
const {
finallyFunc(acceptFunc());
}
};
/**
* Wrap OpenSSL SSL_CTX into a class.
*/
class SSLContext {
public:
enum SSLVersion {
SSLv2,
SSLv3,
TLSv1, // support TLS 1.0+
TLSv1_2, // support for only TLS 1.2+
};
/**
* Defines the way that peers are verified.
**/
enum SSLVerifyPeerEnum {
// Used by AsyncSSLSocket to delegate to the SSLContext's setting
USE_CTX,
// For server side - request a client certificate and verify the
// certificate if it is sent. Does not fail if the client does not present
// a certificate.
// For client side - validates the server certificate or fails.
VERIFY,
// For server side - same as VERIFY but will fail if no certificate
// is sent.
// For client side - same as VERIFY.
VERIFY_REQ_CLIENT_CERT,
// No verification is done for both server and client side.
NO_VERIFY
};
struct NextProtocolsItem {
NextProtocolsItem(int wt, const std::list<std::string>& ptcls)
: weight(wt), protocols(ptcls) {}
int weight;
std::list<std::string> protocols;
};
// Function that selects a client protocol given the server's list
using ClientProtocolFilterCallback = bool (*)(
unsigned char**,
unsigned int*,
const unsigned char*,
unsigned int);
/**
* Convenience function to call getErrors() with the current errno value.
*
* Make sure that you only call this when there was no intervening operation
* since the last OpenSSL error that may have changed the current errno value.
*/
static std::string getErrors() {
return getErrors(errno);
}
/**
* Constructor.
*
* @param version The lowest or oldest SSL version to support.
*/
explicit SSLContext(SSLVersion version = TLSv1);
/**
* Constructor that helps ease migrations by directly wrapping a provided
* SSL_CTX*
*/
explicit SSLContext(SSL_CTX* ctx);
virtual ~SSLContext();
/**
* Set default ciphers to be used in SSL handshake process.
*
* @param ciphers A list of ciphers to use for TLSv1.0
*/
virtual void ciphers(const std::string& ciphers);
/**
* Low-level method that attempts to set the provided ciphers on the
* SSL_CTX object, and throws if something goes wrong.
*/
virtual void setCiphersOrThrow(const std::string& ciphers);
/**
* Set default ciphers to be used in SSL handshake process.
*/
template <typename Iterator>
void setCipherList(Iterator ibegin, Iterator iend) {
if (ibegin != iend) {
std::string opensslCipherList;
folly::join(":", ibegin, iend, opensslCipherList);
setCiphersOrThrow(opensslCipherList);
}
}
template <typename Container>
void setCipherList(const Container& cipherList) {
using namespace std;
setCipherList(begin(cipherList), end(cipherList));
}
template <typename Value>
void setCipherList(const std::initializer_list<Value>& cipherList) {
setCipherList(cipherList.begin(), cipherList.end());
}
/**
* Sets the signature algorithms to be used during SSL negotiation
* for TLS1.2+.
*/
template <typename Iterator>
void setSignatureAlgorithms(Iterator ibegin, Iterator iend) {
if (ibegin != iend) {
#if OPENSSL_VERSION_NUMBER >= 0x1000200fL
std::string opensslSigAlgsList;
join(":", ibegin, iend, opensslSigAlgsList);
if (!SSL_CTX_set1_sigalgs_list(ctx_, opensslSigAlgsList.c_str())) {
throw std::runtime_error("SSL_CTX_set1_sigalgs_list " + getErrors());
}
#endif
}
}
template <typename Container>
void setSignatureAlgorithms(const Container& sigalgs) {
using namespace std;
setSignatureAlgorithms(begin(sigalgs), end(sigalgs));
}
template <typename Value>
void setSignatureAlgorithms(const std::initializer_list<Value>& sigalgs) {
setSignatureAlgorithms(sigalgs.begin(), sigalgs.end());
}
/**
* Sets the list of EC curves supported by the client.
*
* @param ecCurves A list of ec curves, eg: P-256
*/
void setClientECCurvesList(const std::vector<std::string>& ecCurves);
/**
* Method to add support for a specific elliptic curve encryption algorithm.
*
* @param curveName: The name of the ec curve to support, eg: prime256v1.
*/
void setServerECCurve(const std::string& curveName);
/**
* Sets an x509 verification param on the context.
*/
void setX509VerifyParam(const ssl::X509VerifyParam& x509VerifyParam);
/**
* Method to set verification option in the context object.
*
* @param verifyPeer SSLVerifyPeerEnum indicating the verification
* method to use.
*/
virtual void setVerificationOption(const SSLVerifyPeerEnum& verifyPeer);
/**
* Method to check if peer verfication is set.
*
* @return true if peer verification is required.
*
*/
virtual bool needsPeerVerification() {
return (
verifyPeer_ == SSLVerifyPeerEnum::VERIFY ||
verifyPeer_ == SSLVerifyPeerEnum::VERIFY_REQ_CLIENT_CERT);
}
/**
* Method to fetch Verification mode for a SSLVerifyPeerEnum.
* verifyPeer cannot be SSLVerifyPeerEnum::USE_CTX since there is no
* context.
*
* @param verifyPeer SSLVerifyPeerEnum for which the flags need to
* to be returned
*
* @return mode flags that can be used with SSL_set_verify
*/
static int getVerificationMode(const SSLVerifyPeerEnum& verifyPeer);
/**
* Method to fetch Verification mode determined by the options
* set using setVerificationOption.
*
* @return mode flags that can be used with SSL_set_verify
*/
virtual int getVerificationMode();
/**
* Enable/Disable authentication. Peer name validation can only be done
* if checkPeerCert is true.
*
* @param checkPeerCert If true, require peer to present valid certificate
* @param checkPeerName If true, validate that the certificate common name
* or alternate name(s) of peer matches the hostname
* used to connect.
* @param peerName If non-empty, validate that the certificate common
* name of peer matches the given string (altername
* name(s) are not used in this case).
*/
virtual void authenticate(
bool checkPeerCert,
bool checkPeerName,
const std::string& peerName = std::string());
/**
* Loads a certificate chain stored on disk to be sent to the peer during
* TLS connection establishment.
*
* @param path Path to the certificate file
* @param format Certificate file format
*/
virtual void loadCertificate(const char* path, const char* format = "PEM");
/**
* Loads a PEM formatted certificate chain from memory to be sent to the peer
* during TLS connection establishment.
*
* @param cert A PEM formatted certificate
*/
virtual void loadCertificateFromBufferPEM(folly::StringPiece cert);
/**
* Load private key.
*
* @param path Path to the private key file
* @param format Private key file format
*/
virtual void loadPrivateKey(const char* path, const char* format = "PEM");
/**
* Load private key from memory.
*
* @param pkey A PEM formatted key
*/
virtual void loadPrivateKeyFromBufferPEM(folly::StringPiece pkey);
/**
* Load cert and key from PEM buffers. Guaranteed to throw if cert and
* private key mismatch so no need to call isCertKeyPairValid.
*
* @param cert A PEM formatted certificate
* @param pkey A PEM formatted key
*/
virtual void loadCertKeyPairFromBufferPEM(
folly::StringPiece cert,
folly::StringPiece pkey);
/**
* Load cert and key from files. Guaranteed to throw if cert and key mismatch.
* Equivalent to calling loadCertificate() and loadPrivateKey().
*
* @param certPath Path to the certificate file
* @param keyPath Path to the private key file
* @param certFormat Certificate file format
* @param keyFormat Private key file format
*/
virtual void loadCertKeyPairFromFiles(
const char* certPath,
const char* keyPath,
const char* certFormat = "PEM",
const char* keyFormat = "PEM");
/**
* Call after both cert and key are loaded to check if cert matches key.
* Must call if private key is loaded before loading the cert.
* No need to call if cert is loaded first before private key.
* @return true if matches, or false if mismatch.
*/
virtual bool isCertKeyPairValid() const;
/**
* Load trusted certificates from specified file.
*
* @param path Path to trusted certificate file
*/
virtual void loadTrustedCertificates(const char* path);
/**
* Load trusted certificates from specified X509 certificate store.
*
* @param store X509 certificate store.
*/
virtual void loadTrustedCertificates(X509_STORE* store);
/**
* Load a client CA list for validating clients
*/
virtual void loadClientCAList(const char* path);
/**
* Override default OpenSSL password collector.
*
* @param collector Instance of user defined password collector
*/
virtual void passwordCollector(std::shared_ptr<PasswordCollector> collector);
/**
* Obtain password collector.
*
* @return User defined password collector
*/
virtual std::shared_ptr<PasswordCollector> passwordCollector() {
return collector_;
}
#if FOLLY_OPENSSL_HAS_SNI
/**
* Provide SNI support
*/
enum ServerNameCallbackResult {
SERVER_NAME_FOUND,
SERVER_NAME_NOT_FOUND,
SERVER_NAME_NOT_FOUND_ALERT_FATAL,
};
/**
* Callback function from openssl to give the application a
* chance to check the tlsext_hostname just right after parsing
* the Client Hello or Server Hello message.
*
* It is for the server to switch the SSL to another SSL_CTX
* to continue the handshake. (i.e. Server Name Indication, SNI, in RFC6066).
*
* If the ServerNameCallback returns:
* SERVER_NAME_FOUND:
* server: Send a tlsext_hostname in the Server Hello
* client: No-effect
* SERVER_NAME_NOT_FOUND:
* server: Does not send a tlsext_hostname in Server Hello
* and continue the handshake.
* client: No-effect
* SERVER_NAME_NOT_FOUND_ALERT_FATAL:
* server and client: Send fatal TLS1_AD_UNRECOGNIZED_NAME alert to
* the peer.
*
* Quote from RFC 6066:
* "...
* If the server understood the ClientHello extension but
* does not recognize the server name, the server SHOULD take one of two
* actions: either abort the handshake by sending a fatal-level
* unrecognized_name(112) alert or continue the handshake. It is NOT
* RECOMMENDED to send a warning-level unrecognized_name(112) alert,
* because the client's behavior in response to warning-level alerts is
* unpredictable.
* ..."
*/
/**
* Set the ServerNameCallback
*/
typedef std::function<ServerNameCallbackResult(SSL* ssl)> ServerNameCallback;
virtual void setServerNameCallback(const ServerNameCallback& cb);
/**
* Generic callbacks that are run after we get the Client Hello (right
* before we run the ServerNameCallback)
*/
typedef std::function<void(SSL* ssl)> ClientHelloCallback;
virtual void addClientHelloCallback(const ClientHelloCallback& cb);
#endif // FOLLY_OPENSSL_HAS_SNI
/**
* Create an SSL object from this context.
*/
SSL* createSSL() const;
/**
* Sets the namespace to use for sessions created from this context.
*/
void setSessionCacheContext(const std::string& context);
/**
* Set the options on the SSL_CTX object.
*/
void setOptions(long options);
#if FOLLY_OPENSSL_HAS_ALPN
/**
* Set the list of protocols that this SSL context supports. In client
* mode, this is the list of protocols that will be advertised for Application
* Layer Protocol Negotiation (ALPN). In server mode, the first protocol
* advertised by the client that is also on this list is chosen.
* Invoking this function with a list of length zero causes ALPN to be
* disabled.
*
* @param protocols List of protocol names. This method makes a copy,
* so the caller needn't keep the list in scope after
* the call completes. The list must have at least
* one element to enable ALPN. Each element must have
* a string length < 256.
* @return true if ALPN has been activated. False if ALPN is disabled.
*/
bool setAdvertisedNextProtocols(const std::list<std::string>& protocols);
/**
* Set weighted list of lists of protocols that this SSL context supports.
* In server mode, each element of the list contains a list of protocols that
* could be advertised for Application Layer Protocol Negotiation (ALPN).
* The list of protocols that will be advertised to a client is selected
* randomly, based on weights of elements. Client mode doesn't support
* randomized ALPN, so this list should contain only 1 element. The first
* protocol advertised by the client that is also on the list of protocols
* of this element is chosen. Invoking this function with a list of length
* zero causes ALPN to be disabled.
*
* @param items List of NextProtocolsItems, Each item contains a list of
* protocol names and weight. After the call of this fucntion
* each non-empty list of protocols will be advertised with
* probability weight/sum_of_weights. This method makes a copy,
* so the caller needn't keep the list in scope after the call
* completes. The list must have at least one element with
* non-zero weight and non-empty protocols list to enable NPN.
* Each name of the protocol must have a string length < 256.
* @return true if ALPN has been activated. False if ALPN is disabled.
*/
bool setRandomizedAdvertisedNextProtocols(
const std::list<NextProtocolsItem>& items);
/**
* Disables ALPN on this SSL context.
*/
void unsetNextProtocols();
void deleteNextProtocolsStrings();
#endif // FOLLY_OPENSSL_HAS_ALPN
/**
* Gets the underlying SSL_CTX for advanced usage
*/
SSL_CTX* getSSLCtx() const {
return ctx_;
}
/**
* Examine OpenSSL's error stack, and return a string description of the
* errors.
*
* This operation removes the errors from OpenSSL's error stack.
*/
static std::string getErrors(int errnoCopy);
bool checkPeerName() {
return checkPeerName_;
}
std::string peerFixedName() {
return peerFixedName_;
}
#if defined(SSL_MODE_HANDSHAKE_CUTTHROUGH)
/**
* Enable TLS false start, saving a roundtrip for full handshakes. Will only
* be used if the server uses NPN or ALPN, and a strong forward-secure cipher
* is negotiated.
*/
void enableFalseStart();
#endif
/**
* Sets the runner used for SSL_accept. If none is given, the accept will be
* done directly.
*/
void sslAcceptRunner(std::unique_ptr<SSLAcceptRunner> runner) {
if (nullptr == runner) {
LOG(ERROR) << "Ignore invalid runner";
return;
}
sslAcceptRunner_ = std::move(runner);
}
const SSLAcceptRunner* sslAcceptRunner() {
return sslAcceptRunner_.get();
}
/**
* Helper to match a hostname versus a pattern.
*/
static bool matchName(const char* host, const char* pattern, int size);
[[deprecated("Use folly::ssl::init")]] static void initializeOpenSSL();
protected:
SSL_CTX* ctx_;
private:
SSLVerifyPeerEnum verifyPeer_{SSLVerifyPeerEnum::NO_VERIFY};
bool checkPeerName_;
std::string peerFixedName_;
std::shared_ptr<PasswordCollector> collector_;
#if FOLLY_OPENSSL_HAS_SNI
ServerNameCallback serverNameCb_;
std::vector<ClientHelloCallback> clientHelloCbs_;
#endif
ClientProtocolFilterCallback clientProtoFilter_{nullptr};
static bool initialized_;
std::unique_ptr<SSLAcceptRunner> sslAcceptRunner_;
#if FOLLY_OPENSSL_HAS_ALPN
struct AdvertisedNextProtocolsItem {
unsigned char* protocols;
unsigned length;
};
/**
* Wire-format list of advertised protocols for use in NPN.
*/
std::vector<AdvertisedNextProtocolsItem> advertisedNextProtocols_;
std::vector<int> advertisedNextProtocolWeights_;
std::discrete_distribution<int> nextProtocolDistribution_;
static int advertisedNextProtocolCallback(
SSL* ssl,
const unsigned char** out,
unsigned int* outlen,
void* data);
static int alpnSelectCallback(
SSL* ssl,
const unsigned char** out,
unsigned char* outlen,
const unsigned char* in,
unsigned int inlen,
void* data);
size_t pickNextProtocols();
#endif // FOLLY_OPENSSL_HAS_ALPN
static int passwordCallback(char* password, int size, int, void* data);
#if FOLLY_OPENSSL_HAS_SNI
/**
* The function that will be called directly from openssl
* in order for the application to get the tlsext_hostname just after
* parsing the Client Hello or Server Hello message. It will then call
* the serverNameCb_ function object. Hence, it is sort of a
* wrapper/proxy between serverNameCb_ and openssl.
*
* The openssl's primary intention is for SNI support, but we also use it
* generically for performing logic after the Client Hello comes in.
*/
static int baseServerNameOpenSSLCallback(
SSL* ssl,
int* al /* alert (return value) */,
void* data);
#endif
std::string providedCiphersString_;
};
typedef std::shared_ptr<SSLContext> SSLContextPtr;
std::ostream& operator<<(
std::ostream& os,
const folly::PasswordCollector& collector);
} // namespace folly