SourceLayout: shuffle PeerConnector classes to separate units

[thirdparty/squid.git] / src / ssl / PeekingPeerConnector.cc

/*
 * Copyright (C) 1996-2016 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */

/* DEBUG: section 83    SSL-Bump Server/Peer negotiation */

#include "squid.h"
#include "acl/FilledChecklist.h"
#include "client_side.h"
#include "errorpage.h"
#include "fde.h"
#include "HttpRequest.h"
#include "security/NegotiationHistory.h"
#include "SquidConfig.h"
#include "ssl/bio.h"
#include "ssl/PeekingPeerConnector.h"
#include "ssl/ServerBump.h"

CBDATA_NAMESPACED_CLASS_INIT(Ssl, PeekingPeerConnector);

void switchToTunnel(HttpRequest *request, Comm::ConnectionPointer & clientConn, Comm::ConnectionPointer &srvConn);

void
Ssl::PeekingPeerConnector::cbCheckForPeekAndSpliceDone(allow_t answer, void *data)
{
    Ssl::PeekingPeerConnector *peerConnect = (Ssl::PeekingPeerConnector *) data;
    // Use job calls to add done() checks and other job logic/protections.
    CallJobHere1(83, 7, CbcPointer<PeekingPeerConnector>(peerConnect), Ssl::PeekingPeerConnector, checkForPeekAndSpliceDone, answer);
}

void
Ssl::PeekingPeerConnector::checkForPeekAndSpliceDone(allow_t answer)
{
    const Ssl::BumpMode finalAction = (answer.code == ACCESS_ALLOWED) ?
                                      static_cast<Ssl::BumpMode>(answer.kind):
                                      checkForPeekAndSpliceGuess();
    checkForPeekAndSpliceMatched(finalAction);
}

void
Ssl::PeekingPeerConnector::checkForPeekAndSplice()
{
    // Mark Step3 of bumping
    if (request->clientConnectionManager.valid()) {
        if (Ssl::ServerBump *serverBump = request->clientConnectionManager->serverBump()) {
            serverBump->step = Ssl::bumpStep3;
        }
    }

    handleServerCertificate();

    ACLFilledChecklist *acl_checklist = new ACLFilledChecklist(
        ::Config.accessList.ssl_bump,
        request.getRaw(), NULL);
    acl_checklist->banAction(allow_t(ACCESS_ALLOWED, Ssl::bumpNone));
    acl_checklist->banAction(allow_t(ACCESS_ALLOWED, Ssl::bumpPeek));
    acl_checklist->banAction(allow_t(ACCESS_ALLOWED, Ssl::bumpStare));
    acl_checklist->banAction(allow_t(ACCESS_ALLOWED, Ssl::bumpClientFirst));
    acl_checklist->banAction(allow_t(ACCESS_ALLOWED, Ssl::bumpServerFirst));
    Security::SessionPtr ssl = fd_table[serverConn->fd].ssl.get();
    BIO *b = SSL_get_rbio(ssl);
    Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(b->ptr);
    if (!srvBio->canSplice())
        acl_checklist->banAction(allow_t(ACCESS_ALLOWED, Ssl::bumpSplice));
    if (!srvBio->canBump())
        acl_checklist->banAction(allow_t(ACCESS_ALLOWED, Ssl::bumpBump));
    acl_checklist->nonBlockingCheck(Ssl::PeekingPeerConnector::cbCheckForPeekAndSpliceDone, this);
}

void
Ssl::PeekingPeerConnector::checkForPeekAndSpliceMatched(const Ssl::BumpMode action)
{
    Security::SessionPtr ssl = fd_table[serverConn->fd].ssl.get();
    BIO *b = SSL_get_rbio(ssl);
    Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(b->ptr);
    debugs(83,5, "Will check for peek and splice on FD " << serverConn->fd);

    Ssl::BumpMode finalAction = action;
    Must(finalAction == Ssl::bumpSplice || finalAction == Ssl::bumpBump || finalAction == Ssl::bumpTerminate);
    // Record final decision
    if (request->clientConnectionManager.valid()) {
        request->clientConnectionManager->sslBumpMode = finalAction;
        request->clientConnectionManager->serverBump()->act.step3 = finalAction;
    }

    if (finalAction == Ssl::bumpTerminate) {
        serverConn->close();
        clientConn->close();
    } else if (finalAction != Ssl::bumpSplice) {
        //Allow write, proceed with the connection
        srvBio->holdWrite(false);
        srvBio->recordInput(false);
        debugs(83,5, "Retry the fwdNegotiateSSL on FD " << serverConn->fd);
        Ssl::PeerConnector::noteWantWrite();
    } else {
        splice = true;
        // Ssl Negotiation stops here. Last SSL checks for valid certificates
        // and if done, switch to tunnel mode
        if (sslFinalized()) {
            debugs(83,5, "Abort NegotiateSSL on FD " << serverConn->fd << " and splice the connection");
        }
    }
}

Ssl::BumpMode
Ssl::PeekingPeerConnector::checkForPeekAndSpliceGuess() const
{
    if (const ConnStateData *csd = request->clientConnectionManager.valid()) {
        const Ssl::BumpMode currentMode = csd->sslBumpMode;
        if (currentMode == Ssl::bumpStare) {
            debugs(83,5, "default to bumping after staring");
            return Ssl::bumpBump;
        }
        debugs(83,5, "default to splicing after " << currentMode);
    } else {
        debugs(83,3, "default to splicing due to missing info");
    }

    return Ssl::bumpSplice;
}

Security::ContextPtr
Ssl::PeekingPeerConnector::getSslContext()
{
    // XXX: locate a per-server context in Security:: instead
    return ::Config.ssl_client.sslContext;
}

Security::SessionPtr
Ssl::PeekingPeerConnector::initializeSsl()
{
    auto ssl = Ssl::PeerConnector::initializeSsl();
    if (!ssl)
        return nullptr;

    if (ConnStateData *csd = request->clientConnectionManager.valid()) {

        // client connection is required in the case we need to splice
        // or terminate client and server connections
        assert(clientConn != NULL);
        SBuf *hostName = NULL;
        Ssl::ClientBio *cltBio = NULL;

        //Enable Status_request tls extension, required to bump some clients
        SSL_set_tlsext_status_type(ssl, TLSEXT_STATUSTYPE_ocsp);

        // In server-first bumping mode, clientSsl is NULL.
        if (auto clientSsl = fd_table[clientConn->fd].ssl.get()) {
            BIO *b = SSL_get_rbio(clientSsl);
            cltBio = static_cast<Ssl::ClientBio *>(b->ptr);
            const Ssl::Bio::sslFeatures &features = cltBio->receivedHelloFeatures();
            if (!features.serverName.isEmpty())
                hostName = new SBuf(features.serverName);
        }

        if (!hostName) {
            // While we are peeking at the certificate, we may not know the server
            // name that the client will request (after interception or CONNECT)
            // unless it was the CONNECT request with a user-typed address.
            const bool isConnectRequest = !csd->port->flags.isIntercepted();
            if (!request->flags.sslPeek || isConnectRequest)
                hostName = new SBuf(request->url.host());
        }

        if (hostName)
            SSL_set_ex_data(ssl, ssl_ex_index_server, (void*)hostName);

        Must(!csd->serverBump() || csd->serverBump()->step <= Ssl::bumpStep2);
        if (csd->sslBumpMode == Ssl::bumpPeek || csd->sslBumpMode == Ssl::bumpStare) {
            assert(cltBio);
            const Ssl::Bio::sslFeatures &features = cltBio->receivedHelloFeatures();
            if (features.sslVersion != -1) {
                features.applyToSSL(ssl, csd->sslBumpMode);
                // Should we allow it for all protocols?
                if (features.sslVersion >= 3) {
                    BIO *b = SSL_get_rbio(ssl);
                    Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(b->ptr);
                    // Inherite client features, like SSL version, SNI and other
                    srvBio->setClientFeatures(features);
                    srvBio->recordInput(true);
                    srvBio->mode(csd->sslBumpMode);
                }
            }
        } else {
            // Set client SSL options
            SSL_set_options(ssl, ::Security::ProxyOutgoingConfig.parsedOptions);

            // Use SNI TLS extension only when we connect directly
            // to the origin server and we know the server host name.
            const char *sniServer = NULL;
            const bool redirected = request->flags.redirected && ::Config.onoff.redir_rewrites_host;
            if (!hostName || redirected)
                sniServer = !request->url.hostIsNumeric() ? request->url.host() : NULL;
            else
                sniServer = hostName->c_str();

            if (sniServer)
                Ssl::setClientSNI(ssl, sniServer);
        }

        // store peeked cert to check SQUID_X509_V_ERR_CERT_CHANGE
        X509 *peeked_cert;
        if (csd->serverBump() &&
                (peeked_cert = csd->serverBump()->serverCert.get())) {
            CRYPTO_add(&(peeked_cert->references),1,CRYPTO_LOCK_X509);
            SSL_set_ex_data(ssl, ssl_ex_index_ssl_peeked_cert, peeked_cert);
        }
    }

    return ssl;
}

void
Ssl::PeekingPeerConnector::noteNegotiationDone(ErrorState *error)
{
    Security::SessionPtr ssl = fd_table[serverConnection()->fd].ssl.get();

    // Check the list error with
    if (!request->clientConnectionManager.valid() || ! ssl)
        return;

    // remember the server certificate from the ErrorDetail object
    if (Ssl::ServerBump *serverBump = request->clientConnectionManager->serverBump()) {
        // remember validation errors, if any
        if (certErrors) {
            if (serverBump->sslErrors)
                cbdataReferenceDone(serverBump->sslErrors);
            serverBump->sslErrors = cbdataReference(certErrors);
        }

        if (!serverBump->serverCert.get()) {
            // remember the server certificate from the ErrorDetail object
            if (error && error->detail && error->detail->peerCert())
                serverBump->serverCert.resetAndLock(error->detail->peerCert());
            else {
                handleServerCertificate();
            }
        }

        if (error) {
            // For intercepted connections, set the host name to the server
            // certificate CN. Otherwise, we just hope that CONNECT is using
            // a user-entered address (a host name or a user-entered IP).
            const bool isConnectRequest = !request->clientConnectionManager->port->flags.isIntercepted();
            if (request->flags.sslPeek && !isConnectRequest) {
                if (X509 *srvX509 = serverBump->serverCert.get()) {
                    if (const char *name = Ssl::CommonHostName(srvX509)) {
                        request->url.host(name);
                        debugs(83, 3, "reset request host: " << name);
                    }
                }
            }
        }
    }

    // retrieve TLS server information if any
    serverConnection()->tlsNegotiations()->fillWith(ssl);
    if (!error) {
        serverCertificateVerified();
        if (splice) {
            //retrieved received TLS client informations
            auto clientSsl = fd_table[clientConn->fd].ssl.get();
            clientConn->tlsNegotiations()->fillWith(clientSsl);
            switchToTunnel(request.getRaw(), clientConn, serverConn);
        }
    }
}

void
Ssl::PeekingPeerConnector::noteWantWrite()
{
    const int fd = serverConnection()->fd;
    Security::SessionPtr ssl = fd_table[fd].ssl.get();
    BIO *b = SSL_get_rbio(ssl);
    Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(b->ptr);

    if ((srvBio->bumpMode() == Ssl::bumpPeek || srvBio->bumpMode() == Ssl::bumpStare) && srvBio->holdWrite()) {
        debugs(81, DBG_IMPORTANT, "hold write on SSL connection on FD " << fd);
        checkForPeekAndSplice();
        return;
    }

    Ssl::PeerConnector::noteWantWrite();
}

void
Ssl::PeekingPeerConnector::noteSslNegotiationError(const int result, const int ssl_error, const int ssl_lib_error)
{
    const int fd = serverConnection()->fd;
    Security::SessionPtr ssl = fd_table[fd].ssl.get();
    BIO *b = SSL_get_rbio(ssl);
    Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(b->ptr);

    // In Peek mode, the ClientHello message sent to the server. If the
    // server resuming a previous (spliced) SSL session with the client,
    // then probably we are here because local SSL object does not know
    // anything about the session being resumed.
    //
    if (srvBio->bumpMode() == Ssl::bumpPeek && (resumingSession = srvBio->resumingSession())) {
        // we currently splice all resumed sessions unconditionally
        if (const bool spliceResumed = true) {
            bypassCertValidator();
            checkForPeekAndSpliceMatched(Ssl::bumpSplice);
            return;
        } // else fall through to find a matching ssl_bump action (with limited info)
    }

    // If we are in peek-and-splice mode and still we did not write to
    // server yet, try to see if we should splice.
    // In this case the connection can be saved.
    // If the checklist decision is do not splice a new error will
    // occur in the next SSL_connect call, and we will fail again.
    // Abort on certificate validation errors to avoid splicing and
    // thus hiding them.
    // Abort if no certificate found probably because of malformed or
    // unsupported server Hello message (TODO: make configurable).
    if (!SSL_get_ex_data(ssl, ssl_ex_index_ssl_error_detail) &&
            (srvBio->bumpMode() == Ssl::bumpPeek  || srvBio->bumpMode() == Ssl::bumpStare) && srvBio->holdWrite()) {
        Security::CertPointer serverCert(SSL_get_peer_certificate(ssl));
        if (serverCert.get()) {
            debugs(81, 3, "Error ("  << ERR_error_string(ssl_lib_error, NULL) <<  ") but, hold write on SSL connection on FD " << fd);
            checkForPeekAndSplice();
            return;
        }
    }

    // else call parent noteNegotiationError to produce an error page
    Ssl::PeerConnector::noteSslNegotiationError(result, ssl_error, ssl_lib_error);
}

void
Ssl::PeekingPeerConnector::handleServerCertificate()
{
    if (serverCertificateHandled)
        return;

    if (ConnStateData *csd = request->clientConnectionManager.valid()) {
        const int fd = serverConnection()->fd;
        Security::SessionPtr ssl = fd_table[fd].ssl.get();
        Security::CertPointer serverCert(SSL_get_peer_certificate(ssl));
        if (!serverCert.get())
            return;

        serverCertificateHandled = true;

        // remember the server certificate for later use
        if (Ssl::ServerBump *serverBump = csd->serverBump()) {
            serverBump->serverCert.reset(serverCert.release());
        }
    }
}

void
Ssl::PeekingPeerConnector::serverCertificateVerified()
{
    if (ConnStateData *csd = request->clientConnectionManager.valid()) {
        Security::CertPointer serverCert;
        if(Ssl::ServerBump *serverBump = csd->serverBump())
            serverCert.resetAndLock(serverBump->serverCert.get());
        else {
            const int fd = serverConnection()->fd;
            Security::SessionPtr ssl = fd_table[fd].ssl.get();
            serverCert.reset(SSL_get_peer_certificate(ssl));
        }
        if (serverCert.get()) {
            csd->resetSslCommonName(Ssl::CommonHostName(serverCert.get()));
            debugs(83, 5, "HTTPS server CN: " << csd->sslCommonName() <<
                   " bumped: " << *serverConnection());
        }
    }
}