// **********************************************************************
//
// Copyright (c) 2003-2007 ZeroC, Inc. All rights reserved.
//
// This copy of Ice is licensed to you under the terms described in the
// ICE_LICENSE file included in this distribution.
//
// **********************************************************************

#include <IceSSL/Instance.h>
#include <IceSSL/EndpointI.h>
#include <IceSSL/Util.h>
#include <IceSSL/TrustManager.h>

#include <Ice/Communicator.h>
#include <Ice/LocalException.h>
#include <Ice/Logger.h>
#include <Ice/LoggerUtil.h>
#include <Ice/Properties.h>
#include <Ice/ProtocolPluginFacade.h>

#include <openssl/err.h>

#include <IceUtil/DisableWarnings.h>

using namespace std;
using namespace Ice;
using namespace IceSSL;

IceUtil::Shared* IceInternal::upCast(IceSSL::Instance* p) { return p; }

extern "C"
{

int
IceSSL_opensslPasswordCallback(char* buf, int size, int flag, void* userData)
{
    IceSSL::Instance* p = reinterpret_cast<IceSSL::Instance*>(userData);
    string passwd = p->password(flag == 1);
    int sz = static_cast<int>(passwd.size());
    if(sz > size)
    {
        sz = size - 1;
    }
    strncpy(buf, passwd.c_str(), sz);
    buf[sz] = '\0';

    memset(&passwd[0], 0, static_cast<size_t>(passwd.size()));

    return sz;
}

#ifndef OPENSSL_NO_DH
DH*
IceSSL_opensslDHCallback(SSL* ssl, int /*isExport*/, int keyLength)
{
    IceSSL::Instance* p = reinterpret_cast<IceSSL::Instance*>(SSL_CTX_get_ex_data(ssl->ctx, 0));
    return p->dhParams(keyLength);
}
#endif

int
IceSSL_opensslVerifyCallback(int ok, X509_STORE_CTX* ctx)
{
    SSL* ssl = reinterpret_cast<SSL*>(X509_STORE_CTX_get_ex_data(ctx, SSL_get_ex_data_X509_STORE_CTX_idx()));
    IceSSL::Instance* p = reinterpret_cast<IceSSL::Instance*>(SSL_CTX_get_ex_data(ssl->ctx, 0));
    return p->verifyCallback(ok, ssl, ctx);
}

}

static bool
passwordError()
{
    int reason = ERR_GET_REASON(ERR_peek_error());
    return (reason == PEM_R_BAD_BASE64_DECODE ||
            reason == PEM_R_BAD_DECRYPT ||
            reason == PEM_R_BAD_PASSWORD_READ ||
            reason == PEM_R_PROBLEMS_GETTING_PASSWORD);
}

IceSSL::Instance::Instance(const CommunicatorPtr& communicator) :
    _logger(communicator->getLogger()),
    _ctx(0)
{
    __setNoDelete(true);

    _facade = IceInternal::getProtocolPluginFacade(communicator);
    _securityTraceLevel = communicator->getProperties()->getPropertyAsInt("IceSSL.Trace.Security");
    _securityTraceCategory = "Security";
    _trustManager = new TrustManager(communicator);
    
    //
    // Register the endpoint factory. We have to do this now, rather than
    // in initialize, because the communicator may need to interpret
    // proxies before the plugin is fully initialized.
    //
    _facade->addEndpointFactory(new EndpointFactoryI(this));

    __setNoDelete(false);
}

void
IceSSL::Instance::initialize()
{
    if(_ctx)
    {
        return;
    }

    _ctx = SSL_CTX_new(SSLv23_method());
    if(!_ctx)
    {
        PluginInitializationException ex(__FILE__, __LINE__);
        ex.reason = "IceSSL: unable to create SSL context:\n" + sslErrors();
        throw ex;
    }

    try
    {
        //
        // Store a pointer to ourself for use in OpenSSL callbacks.
        //
        SSL_CTX_set_ex_data(_ctx, 0, this);

        //
        // This is necessary for successful interop with Java. Without it, a Java
        // client would fail to reestablish a connection: the server gets the
        // error "session id context uninitialized" and the client receives
        // "SSLHandshakeException: Remote host closed connection during handshake".
        //
        SSL_CTX_set_session_cache_mode(_ctx, SSL_SESS_CACHE_OFF);

        PropertiesPtr properties = communicator()->getProperties();
        const string propPrefix = "IceSSL.";

        //
        // Check for a default directory. We look in this directory for
        // files mentioned in the configuration.
        //
        {
            _defaultDir = properties->getProperty(propPrefix + "DefaultDir");
        }

        //
        // Select protocols.
        //
        {
            string protocols = properties->getProperty(propPrefix + "Protocols");
            if(!protocols.empty())
            {
                parseProtocols(protocols);
            }
        }

        //
        // CheckCertName determines whether we compare the name in a peer's
        // certificate against its hostname.
        //
        {
            _checkCertName = properties->getPropertyAsIntWithDefault(propPrefix + "CheckCertName", 0) > 0;
        }

        //
        // VerifyDepthMax establishes the maximum length of a peer's certificate
        // chain, including the peer's certificate. A value of 0 means there is
        // no maximum.
        //
        {
            _verifyDepthMax = properties->getPropertyAsIntWithDefault(propPrefix + "VerifyDepthMax", 2);
        }

        //
        // Determine whether a certificate is required from the peer.
        //
        {
            int verifyPeer = properties->getPropertyAsIntWithDefault(propPrefix + "VerifyPeer", 2);
            int sslVerifyMode;
            switch(verifyPeer)
            {
            case 0:
                sslVerifyMode = SSL_VERIFY_NONE;
                break;
            case 1:
                sslVerifyMode = SSL_VERIFY_PEER;
                break;
            case 2:
                sslVerifyMode = SSL_VERIFY_PEER|SSL_VERIFY_FAIL_IF_NO_PEER_CERT;
                break;
            default:
            {
                PluginInitializationException ex(__FILE__, __LINE__);
                ex.reason = "IceSSL: invalid value for " + propPrefix + "VerifyPeer";
                throw ex;
            }
            }
            SSL_CTX_set_verify(_ctx, sslVerifyMode, IceSSL_opensslVerifyCallback);
        }

        //
        // If the configuration defines a password, or the application has supplied
        // a password prompt object, then register a password callback. Otherwise,
        // let OpenSSL use its default behavior.
        //
        {
            // TODO: Support quoted value?
            string password = properties->getProperty(propPrefix + "Password");
            if(!password.empty() || _prompt)
            {
                SSL_CTX_set_default_passwd_cb(_ctx, IceSSL_opensslPasswordCallback);
                SSL_CTX_set_default_passwd_cb_userdata(_ctx, this);
                _password = password;
            }
        }

        int passwordRetryMax = properties->getPropertyAsIntWithDefault(propPrefix + "PasswordRetryMax", 3);

        //
        // Establish the location of CA certificates.
        //
        {
            string caFile = properties->getProperty(propPrefix + "CertAuthFile");
            string caDir = properties->getPropertyWithDefault(propPrefix + "CertAuthDir", _defaultDir);
            const char* file = 0;
            const char* dir = 0;
            if(!caFile.empty())
            {
                if(!checkPath(caFile, _defaultDir, false))
                {
                    PluginInitializationException ex(__FILE__, __LINE__);
                    ex.reason = "IceSSL: CA certificate file not found:\n" + caFile;
                    throw ex;
                }
                file = caFile.c_str();
            }
            if(!caDir.empty())
            {
                if(!checkPath(caDir, _defaultDir, true))
                {
                    PluginInitializationException ex(__FILE__, __LINE__);
                    ex.reason = "IceSSL: CA certificate directory not found:\n" + caDir;
                    throw ex;
                }
                dir = caDir.c_str();
            }
            if(file || dir)
            {
                //
                // The certificate may be stored in an encrypted file, so handle
                // password retries.
                //
                int count = 0;
                int err = 0;
                while(count < passwordRetryMax)
                {
                    ERR_clear_error();
                    err = SSL_CTX_load_verify_locations(_ctx, file, dir);
                    if(err || !passwordError())
                    {
                        break;
                    }
                    ++count;
                }
                if(err == 0)
                {
                    string msg = "IceSSL: unable to establish CA certificates";
                    if(passwordError())
                    {
                        msg += ":\ninvalid password";
                    }
                    else
                    {
                        string err = sslErrors();
                        if(!err.empty())
                        {
                            msg += ":\n" + err;
                        }
                    }
                    PluginInitializationException ex(__FILE__, __LINE__);
                    ex.reason = msg;
                    throw ex;
                }
            }
        }

        //
        // Establish the certificate chains and private keys. One RSA certificate and
        // one DSA certificate are allowed.
        //
        {
#ifdef _WIN32
            const string sep = ";";
#else
            const string sep = ":";
#endif
            string certFile = properties->getProperty(propPrefix + "CertFile");
            string keyFile = properties->getProperty(propPrefix + "KeyFile");
            vector<string>::size_type numCerts = 0;
            if(!certFile.empty())
            {
                vector<string> files;
                if(!splitString(certFile, sep, false, files) || files.size() > 2)
                {
                    PluginInitializationException ex(__FILE__, __LINE__);
                    ex.reason = "IceSSL: invalid value for " + propPrefix + "CertFile:\n" + certFile;
                    throw ex;
                }
                numCerts = files.size();
                for(vector<string>::iterator p = files.begin(); p != files.end(); ++p)
                {
                    string file = *p;
                    if(!checkPath(file, _defaultDir, false))
                    {
                        PluginInitializationException ex(__FILE__, __LINE__);
                        ex.reason = "IceSSL: certificate file not found:\n" + file;
                        throw ex;
                    }
                    //
                    // The certificate may be stored in an encrypted file, so handle
                    // password retries.
                    //
                    int count = 0;
                    int err = 0;
                    while(count < passwordRetryMax)
                    {
                        ERR_clear_error();
                        err = SSL_CTX_use_certificate_chain_file(_ctx, file.c_str());
                        if(err || !passwordError())
                        {
                            break;
                        }
                        ++count;
                    }
                    if(err == 0)
                    {
                        string msg = "IceSSL: unable to load certificate chain from file " + file;
                        if(passwordError())
                        {
                            msg += ":\ninvalid password";
                        }
                        else
                        {
                            string err = sslErrors();
                            if(!err.empty())
                            {
                                msg += ":\n" + err;
                            }
                        }
                        PluginInitializationException ex(__FILE__, __LINE__);
                        ex.reason = msg;
                        throw ex;
                    }
                }
            }
            if(keyFile.empty())
            {
                keyFile = certFile; // Assume the certificate file also contains the private key.
            }
            if(!keyFile.empty())
            {
                vector<string> files;
                if(!splitString(keyFile, sep, false, files) || files.size() > 2)
                {
                    PluginInitializationException ex(__FILE__, __LINE__);
                    ex.reason = "IceSSL: invalid value for " + propPrefix + "KeyFile:\n" + keyFile;
                    throw ex;
                }
                if(files.size() != numCerts)
                {
                    PluginInitializationException ex(__FILE__, __LINE__);
                    ex.reason = "IceSSL: " + propPrefix + "KeyFile does not agree with " + propPrefix + "CertFile";
                    throw ex;
                }
                for(vector<string>::iterator p = files.begin(); p != files.end(); ++p)
                {
                    string file = *p;
                    if(!checkPath(file, _defaultDir, false))
                    {
                        PluginInitializationException ex(__FILE__, __LINE__);
                        ex.reason = "IceSSL: key file not found:\n" + file;
                        throw ex;
                    }
                    //
                    // The private key may be stored in an encrypted file, so handle
                    // password retries.
                    //
                    int count = 0;
                    int err = 0;
                    while(count < passwordRetryMax)
                    {
                        ERR_clear_error();
                        err = SSL_CTX_use_PrivateKey_file(_ctx, file.c_str(), SSL_FILETYPE_PEM);
                        if(err || !passwordError())
                        {
                            break;
                        }
                        ++count;
                    }
                    if(err == 0)
                    {
                        string msg = "IceSSL: unable to load private key from file " + file;
                        if(passwordError())
                        {
                            msg += ":\ninvalid password";
                        }
                        else
                        {
                            string err = sslErrors();
                            if(!err.empty())
                            {
                                msg += ":\n" + err;
                            }
                        }
                        PluginInitializationException ex(__FILE__, __LINE__);
                        ex.reason = msg;
                        throw ex;
                    }
                }
                if(!SSL_CTX_check_private_key(_ctx))
                {
                    PluginInitializationException ex(__FILE__, __LINE__);
                    ex.reason = "IceSSL: unable to validate private key(s):\n" + sslErrors();
                    throw ex;
                }
            }
        }

        //
        // Establish the cipher list.
        //
        {
            string ciphers = properties->getProperty(propPrefix + "Ciphers");
            if(!ciphers.empty())
            {
                if(!SSL_CTX_set_cipher_list(_ctx, ciphers.c_str()))
                {
                    PluginInitializationException ex(__FILE__, __LINE__);
                    ex.reason = "IceSSL: unable to set ciphers using `" + ciphers + "':\n" + sslErrors();
                    throw ex;
                }
            }
        }

        //
        // Diffie Hellman configuration.
        //
        {
#ifndef OPENSSL_NO_DH
            _dhParams = new DHParams;
            SSL_CTX_set_options(_ctx, SSL_OP_SINGLE_DH_USE);
            SSL_CTX_set_tmp_dh_callback(_ctx, IceSSL_opensslDHCallback);
#endif
            //
            // Properties have the following form:
            //
            // ...DH.<keyLength>=file
            //
            const string dhPrefix = propPrefix + "DH.";
            PropertyDict d = properties->getPropertiesForPrefix(dhPrefix);
            if(!d.empty())
            {
#ifdef OPENSSL_NO_DH
                _logger->warning("IceSSL: OpenSSL is not configured for Diffie Hellman");
#else
                for(PropertyDict::iterator p = d.begin(); p != d.end(); ++p)
                {
                    string s = p->first.substr(dhPrefix.size());
                    int keyLength = atoi(s.c_str());
                    if(keyLength > 0)
                    {
                        string file = p->second;
                        if(!checkPath(file, _defaultDir, false))
                        {
                            PluginInitializationException ex(__FILE__, __LINE__);
                            ex.reason = "IceSSL: DH parameter file not found:\n" + file;
                            throw ex;
                        }
                        if(!_dhParams->add(keyLength, file))
                        {
                            PluginInitializationException ex(__FILE__, __LINE__);
                            ex.reason = "IceSSL: unable to read DH parameter file " + file;
                            throw ex;
                        }
                    }
                }
#endif
            }
        }
    }
    catch(...)
    {
        SSL_CTX_free(_ctx);
        _ctx = 0;
        throw;
    }
}

void
IceSSL::Instance::context(SSL_CTX* context)
{
    if(_ctx)
    {
        PluginInitializationException ex(__FILE__, __LINE__);
        ex.reason = "IceSSL: plugin is already initialized";
        throw ex;
    }

    _ctx = context;
}

SSL_CTX*
IceSSL::Instance::context() const
{
    return _ctx;
}

void
IceSSL::Instance::setCertificateVerifier(const CertificateVerifierPtr& verifier)
{
    _verifier = verifier;
}

void
IceSSL::Instance::setPasswordPrompt(const PasswordPromptPtr& prompt)
{
    _prompt = prompt;
}

CommunicatorPtr
IceSSL::Instance::communicator() const
{
    return _facade->getCommunicator();
}

string
IceSSL::Instance::defaultHost() const
{
    return _facade->getDefaultHost();
}

int
IceSSL::Instance::networkTraceLevel() const
{
    return _facade->getNetworkTraceLevel();
}

string
IceSSL::Instance::networkTraceCategory() const
{
    return _facade->getNetworkTraceCategory();
}

int
IceSSL::Instance::securityTraceLevel() const
{
    return _securityTraceLevel;
}

string
IceSSL::Instance::securityTraceCategory() const
{
    return _securityTraceCategory;
}

void
IceSSL::Instance::verifyPeer(SSL* ssl, SOCKET fd, const string& address, const string& adapterName, bool incoming)
{
    long result = SSL_get_verify_result(ssl);
    if(result != X509_V_OK)
    {
        ostringstream ostr;
        ostr << "IceSSL: certificate verification failed:\n" << X509_verify_cert_error_string(result);
        string msg = ostr.str();
        if(_securityTraceLevel >= 1)
        {
            _logger->trace(_securityTraceCategory, msg);
        }
        SecurityException ex(__FILE__, __LINE__);
        ex.reason = msg;
        throw ex;
    }

    X509* rawCert = SSL_get_peer_certificate(ssl);
    CertificatePtr cert;
    if(rawCert != 0)
    {
        cert = new Certificate(rawCert);
    }

    //
    // Extract the IP addresses and the DNS names from the subject
    // alternative names.
    //
    if(cert)
    {
        vector<pair<int, string> > subjectAltNames = cert->getSubjectAlternativeNames();
        vector<string> ipAddresses;
        vector<string> dnsNames;
        for(vector<pair<int, string> >::const_iterator p = subjectAltNames.begin(); p != subjectAltNames.end(); ++p)
        {
            if(p->first == 7)
            {
                ipAddresses.push_back(p->second);
            }
            else if(p->first == 2)
            {
                dnsNames.push_back(p->second);
            }
        }

        //
        // Compare the peer's address against the dnsName and ipAddress values.
        // This is only relevant for an outgoing connection.
        //
        if(!address.empty())
        {
            bool certNameOK = false;

            for(vector<string>::const_iterator p = ipAddresses.begin(); p != ipAddresses.end() && !certNameOK; ++p)
            {
                if(address == *p)
                {
                    certNameOK = true;
                    break;
                }
            }

            if(!certNameOK && !dnsNames.empty())
            {
                string host = address;
                transform(host.begin(), host.end(), host.begin(), ::tolower);
                for(vector<string>::const_iterator p = dnsNames.begin(); p != dnsNames.end() && !certNameOK; ++p)
                {
                    string s = *p;
                    transform(s.begin(), s.end(), s.begin(), ::tolower);
                    if(host == s)
                    {
                        certNameOK = true;
                    }
                }
            }

            //
            // Log a message if the name comparison fails. If CheckCertName is defined,
            // we also raise an exception to abort the connection. Don't log a message if
            // CheckCertName is not defined and a verifier is present.
            //
            if(!certNameOK && (_checkCertName || (_securityTraceLevel >= 1 && !_verifier)))
            {
                ostringstream ostr;
                ostr << "IceSSL: ";
                if(!_checkCertName)
                {
                    ostr << "ignoring ";
                }
                ostr << "certificate validation failure:\npeer certificate does not contain `"
                     << address << "' in its subjectAltName extension";
                if(!dnsNames.empty())
                {
                    ostr << "\nDNS names found in certificate: ";
                    for(vector<string>::const_iterator p = dnsNames.begin(); p != dnsNames.end(); ++p)
                    {
                        if(p != dnsNames.begin())
                        {
                            ostr << ", ";
                        }
                        ostr << *p;
                    }
                }
                if(!ipAddresses.empty())
                {
                    ostr << "\nIP addresses found in certificate: ";
                    for(vector<string>::const_iterator p = ipAddresses.begin(); p != ipAddresses.end(); ++p)
                    {
                        if(p != ipAddresses.begin())
                        {
                            ostr << ", ";
                        }
                        ostr << *p;
                    }
                }
                string msg = ostr.str();
                if(_securityTraceLevel >= 1)
                {
                    Trace out(_logger, _securityTraceCategory);
                    out << msg;
                }
                if(_checkCertName)
                {
                    SecurityException ex(__FILE__, __LINE__);
                    ex.reason = msg;
                    throw ex;
                }
            }
        }
    }

    ConnectionInfo info = populateConnectionInfo(ssl, fd, adapterName, incoming);

    if(_verifyDepthMax > 0 && static_cast<int>(info.certs.size()) > _verifyDepthMax)
    {
        ostringstream ostr;
        ostr << (incoming ? "incoming" : "outgoing") << " connection rejected:\n"
             << "length of peer's certificate chain (" << info.certs.size() << ") exceeds maximum of "
             << _verifyDepthMax;
        string msg = ostr.str();
        if(_securityTraceLevel >= 1)
        {
            _logger->trace(_securityTraceCategory, msg + "\n" + IceInternal::fdToString(fd));
        }
        SecurityException ex(__FILE__, __LINE__);
        ex.reason = msg;
        throw ex;
    }

    if(!_trustManager->verify(info))
    {
        string msg = string(incoming ? "incoming" : "outgoing") + " connection rejected by trust manager";
        if(_securityTraceLevel >= 1)
        {
            _logger->trace(_securityTraceCategory, msg + "\n" + IceInternal::fdToString(fd));
        }
        SecurityException ex(__FILE__, __LINE__);
        ex.reason = msg;
        throw ex;
    }

    if(_verifier && !_verifier->verify(info))
    {
        string msg = string(incoming ? "incoming" : "outgoing") + " connection rejected by certificate verifier";
        if(_securityTraceLevel >= 1)
        {
            _logger->trace(_securityTraceCategory, msg + "\n" + IceInternal::fdToString(fd));
        }
        SecurityException ex(__FILE__, __LINE__);
        ex.reason = msg;
        throw ex;
    }
}

string
IceSSL::Instance::sslErrors() const
{
    return getSslErrors(_securityTraceLevel >= 1);
}

void
IceSSL::Instance::destroy()
{
    _facade = 0;

    if(_ctx)
    {
        SSL_CTX_free(_ctx);
    }
}

string
IceSSL::Instance::password(bool /*encrypting*/)
{
    if(_prompt)
    {
        try
        {
            return _prompt->getPassword();
        }
        catch(...)
        {
            //
            // Don't allow exceptions to cross an OpenSSL boundary.
            //
            return string();
        }
    }
    else
    {
        return _password;
    }
}

int
IceSSL::Instance::verifyCallback(int ok, SSL* ssl, X509_STORE_CTX* c)
{
    if(!ok && _securityTraceLevel >= 1)
    {
        X509* cert = X509_STORE_CTX_get_current_cert(c);
        int err = X509_STORE_CTX_get_error(c);
        char buf[256];

        Trace out(_logger, _securityTraceCategory);
        out << "certificate verification failure\n";

        X509_NAME_oneline(X509_get_issuer_name(cert), buf, static_cast<int>(sizeof(buf)));
        out << "issuer = " << buf << '\n';
        X509_NAME_oneline(X509_get_subject_name(cert), buf, static_cast<int>(sizeof(buf)));
        out << "subject = " << buf << '\n';
        out << "depth = " << X509_STORE_CTX_get_error_depth(c) << '\n';
        out << "error = " << X509_verify_cert_error_string(err) << '\n';
        out << IceInternal::fdToString(SSL_get_fd(ssl));
    }
    return ok;
}

#ifndef OPENSSL_NO_DH
DH*
IceSSL::Instance::dhParams(int keyLength)
{
    return _dhParams->get(keyLength);
}
#endif

void
IceSSL::Instance::traceConnection(SSL* ssl, bool incoming)
{
    Trace out(_logger, _securityTraceCategory);
    out << "SSL summary for " << (incoming ? "incoming" : "outgoing") << " connection\n";
    SSL_CIPHER* cipher = SSL_get_current_cipher(ssl);
    if(!cipher)
    {
        out << "unknown cipher\n";
    }
    else
    {
        out << "cipher = " << SSL_CIPHER_get_name(cipher) << "\n";
        out << "bits = " << SSL_CIPHER_get_bits(cipher, 0) << "\n";
        out << "protocol = " << SSL_get_version(ssl) << "\n";
    }
    out << IceInternal::fdToString(SSL_get_fd(ssl));
}

void
IceSSL::Instance::parseProtocols(const string& val)
{
    const string delim = ", ";
    bool sslv3 = false, tlsv1 = false;
    string::size_type pos = 0;
    while(pos != string::npos)
    {
        pos = val.find_first_not_of(delim, pos);
        if(pos == string::npos)
        {
            break;
        }

        string prot;
        string::size_type end = val.find_first_of(delim, pos);
        if(end == string::npos)
        {
            prot = val.substr(pos);
        }
        else
        {
            prot = val.substr(pos, end - pos);
        }
        pos = end;

        if(prot == "ssl3" || prot == "sslv3")
        {
            sslv3 = true;
        }
        else if(prot == "tls" || prot == "tls1" || prot == "tlsv1")
        {
            tlsv1 = true;
        }
        else
        {
            PluginInitializationException ex(__FILE__, __LINE__);
            ex.reason = "IceSSL: unrecognized protocol `" + prot + "'";
            throw ex;
        }
    }

    long opts = SSL_OP_NO_SSLv2; // SSLv2 is not supported.
    if(!sslv3)
    {
        opts |= SSL_OP_NO_SSLv3;
    }
    if(!tlsv1)
    {
        opts |= SSL_OP_NO_TLSv1;
    }
    SSL_CTX_set_options(_ctx, opts);
}