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

/*
 * Copyright (C) 1996-2015 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 17    Request Forwarding */

#include "squid.h"
#include "acl/FilledChecklist.h"
#include "base/AsyncCbdataCalls.h"
#include "CachePeer.h"
#include "client_side.h"
#include "comm/Loops.h"
#include "Downloader.h"
#include "errorpage.h"
#include "fde.h"
#include "globals.h"
#include "helper/ResultCode.h"
#include "HttpRequest.h"
#include "neighbors.h"
#include "SquidConfig.h"
#include "ssl/bio.h"
#include "ssl/cert_validate_message.h"
#include "ssl/Config.h"
#include "ssl/ErrorDetail.h"
#include "ssl/helper.h"
#include "ssl/PeerConnector.h"
#include "ssl/ServerBump.h"
#include "ssl/support.h"

CBDATA_NAMESPACED_CLASS_INIT(Ssl, PeerConnector);
CBDATA_NAMESPACED_CLASS_INIT(Ssl, BlindPeerConnector);
CBDATA_NAMESPACED_CLASS_INIT(Ssl, PeekingPeerConnector);

Ssl::PeerConnector::PeerConnector(const Comm::ConnectionPointer &aServerConn, AsyncCall::Pointer &aCallback, const time_t timeout) :
    AsyncJob("Ssl::PeerConnector"),
    serverConn(aServerConn),
    certErrors(NULL),
    callback(aCallback),
    negotiationTimeout(timeout),
    startTime(squid_curtime),
    useCertValidator_(false),
    certsDownloads(0)
{
    // if this throws, the caller's cb dialer is not our CbDialer
    Must(dynamic_cast<CbDialer*>(callback->getDialer()));
}

Ssl::PeerConnector::~PeerConnector()
{
    cbdataReferenceDone(certErrors);
    debugs(83, 5, "Peer connector " << this << " gone");
}

bool Ssl::PeerConnector::doneAll() const
{
    return (!callback || callback->canceled()) && AsyncJob::doneAll();
}

/// Preps connection and SSL state. Calls negotiate().
void
Ssl::PeerConnector::start()
{
    AsyncJob::start();

    if (prepareSocket() && (initializeSsl() != NULL))
        negotiateSsl();
}

void
Ssl::PeerConnector::commCloseHandler(const CommCloseCbParams &params)
{
    debugs(83, 5, "FD " << params.fd << ", Ssl::PeerConnector=" << params.data);
    connectionClosed("Ssl::PeerConnector::commCloseHandler");
}

void
Ssl::PeerConnector::connectionClosed(const char *reason)
{
    mustStop(reason);
    callback = NULL;
}

bool
Ssl::PeerConnector::prepareSocket()
{
    const int fd = serverConnection()->fd;
    if (!Comm::IsConnOpen(serverConn) || fd_table[serverConn->fd].closing()) {
        connectionClosed("Ssl::PeerConnector::prepareSocket");
        return false;
    }

    // watch for external connection closures
    typedef CommCbMemFunT<Ssl::PeerConnector, CommCloseCbParams> Dialer;
    closeHandler = JobCallback(9, 5, Dialer, this, Ssl::PeerConnector::commCloseHandler);
    comm_add_close_handler(fd, closeHandler);
    return true;
}

SSL *
Ssl::PeerConnector::initializeSsl()
{
    Security::ContextPtr sslContext(getSslContext());
    assert(sslContext);

    const int fd = serverConnection()->fd;

    SSL *ssl = Ssl::CreateClient(sslContext, fd, "server https start");
    if (!ssl) {
        ErrorState *anErr = new ErrorState(ERR_SOCKET_FAILURE, Http::scInternalServerError, request.getRaw());
        anErr->xerrno = errno;
        debugs(83, DBG_IMPORTANT, "Error allocating SSL handle: " << ERR_error_string(ERR_get_error(), NULL));

        noteNegotiationDone(anErr);
        bail(anErr);
        return NULL;
    }

    // If CertValidation Helper used do not lookup checklist for errors,
    // but keep a list of errors to send it to CertValidator
    if (!Ssl::TheConfig.ssl_crt_validator) {
        // Create the ACL check list now, while we have access to more info.
        // The list is used in ssl_verify_cb() and is freed in ssl_free().
        if (acl_access *acl = ::Config.ssl_client.cert_error) {
            ACLFilledChecklist *check = new ACLFilledChecklist(acl, request.getRaw(), dash_str);
            // check->fd(fd); XXX: need client FD here
            SSL_set_ex_data(ssl, ssl_ex_index_cert_error_check, check);
        }
    }
    return ssl;
}

void
Ssl::PeerConnector::setReadTimeout()
{
    int timeToRead;
    if (negotiationTimeout) {
        const int timeUsed = squid_curtime - startTime;
        const int timeLeft = max(0, static_cast<int>(negotiationTimeout - timeUsed));
        timeToRead = min(static_cast<int>(::Config.Timeout.read), timeLeft);
    } else
        timeToRead = ::Config.Timeout.read;
    AsyncCall::Pointer nil;
    commSetConnTimeout(serverConnection(), timeToRead, nil);
}

void
Ssl::PeerConnector::negotiateSsl()
{
    if (!Comm::IsConnOpen(serverConnection()) || fd_table[serverConnection()->fd].closing())
        return;

    const int fd = serverConnection()->fd;
    SSL *ssl = fd_table[fd].ssl;
    const int result = SSL_connect(ssl);
    if (result <= 0) {
        handleNegotiateError(result);
        return; // we might be gone by now
    }

    if (!sslFinalized())
        return;

    callBack();
}

bool
Ssl::PeerConnector::sslFinalized()
{
    if (Ssl::TheConfig.ssl_crt_validator && useCertValidator_) {
        const int fd = serverConnection()->fd;
        SSL *ssl = fd_table[fd].ssl;

        Ssl::CertValidationRequest validationRequest;
        // WARNING: Currently we do not use any locking for any of the
        // members of the Ssl::CertValidationRequest class. In this code the
        // Ssl::CertValidationRequest object used only to pass data to
        // Ssl::CertValidationHelper::submit method.
        validationRequest.ssl = ssl;
        validationRequest.domainName = request->url.host();
        if (Ssl::CertErrors *errs = static_cast<Ssl::CertErrors *>(SSL_get_ex_data(ssl, ssl_ex_index_ssl_errors)))
            // validationRequest disappears on return so no need to cbdataReference
            validationRequest.errors = errs;
        else
            validationRequest.errors = NULL;
        try {
            debugs(83, 5, "Sending SSL certificate for validation to ssl_crtvd.");
            AsyncCall::Pointer call = asyncCall(83,5, "Ssl::PeerConnector::sslCrtvdHandleReply", Ssl::CertValidationHelper::CbDialer(this, &Ssl::PeerConnector::sslCrtvdHandleReply, nullptr));
            Ssl::CertValidationHelper::GetInstance()->sslSubmit(validationRequest, call);
            return false;
        } catch (const std::exception &e) {
            debugs(83, DBG_IMPORTANT, "ERROR: Failed to compose ssl_crtvd " <<
                   "request for " << validationRequest.domainName <<
                   " certificate: " << e.what() << "; will now block to " <<
                   "validate that certificate.");
            // fall through to do blocking in-process generation.
            ErrorState *anErr = new ErrorState(ERR_GATEWAY_FAILURE, Http::scInternalServerError, request.getRaw());

            noteNegotiationDone(anErr);
            bail(anErr);
            serverConn->close();
            return true;
        }
    }

    noteNegotiationDone(NULL);
    return true;
}

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));
    SSL *ssl = fd_table[serverConn->fd].ssl;
    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)
{
    SSL *ssl = fd_table[serverConn->fd].ssl;
    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->recordInput(false);
        srvBio->holdWrite(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;
}

void
Ssl::PeerConnector::sslCrtvdHandleReply(Ssl::CertValidationResponse::Pointer validationResponse)
{
    Must(validationResponse != NULL);

    Ssl::CertErrors *errs = NULL;
    Ssl::ErrorDetail *errDetails = NULL;
    bool validatorFailed = false;
    if (!Comm::IsConnOpen(serverConnection())) {
        return;
    }

    debugs(83,5, request->url.host() << " cert validation result: " << validationResponse->resultCode);

    if (validationResponse->resultCode == ::Helper::Error)
        errs = sslCrtvdCheckForErrors(*validationResponse, errDetails);
    else if (validationResponse->resultCode != ::Helper::Okay)
        validatorFailed = true;

    if (!errDetails && !validatorFailed) {
        noteNegotiationDone(NULL);
        callBack();
        return;
    }

    if (errs) {
        if (certErrors)
            cbdataReferenceDone(certErrors);
        certErrors = cbdataReference(errs);
    }

    ErrorState *anErr = NULL;
    if (validatorFailed) {
        anErr = new ErrorState(ERR_GATEWAY_FAILURE, Http::scInternalServerError, request.getRaw());
    }  else {
        anErr =  new ErrorState(ERR_SECURE_CONNECT_FAIL, Http::scServiceUnavailable, request.getRaw());
        anErr->detail = errDetails;
        /*anErr->xerrno= Should preserved*/
    }

    noteNegotiationDone(anErr);
    bail(anErr);
    serverConn->close();
    return;
}

/// Checks errors in the cert. validator response against sslproxy_cert_error.
/// The first honored error, if any, is returned via errDetails parameter.
/// The method returns all seen errors except SSL_ERROR_NONE as Ssl::CertErrors.
Ssl::CertErrors *
Ssl::PeerConnector::sslCrtvdCheckForErrors(Ssl::CertValidationResponse const &resp, Ssl::ErrorDetail *& errDetails)
{
    Ssl::CertErrors *errs = NULL;

    ACLFilledChecklist *check = NULL;
    if (acl_access *acl = ::Config.ssl_client.cert_error)
        check = new ACLFilledChecklist(acl, request.getRaw(), dash_str);

    SSL *ssl = fd_table[serverConnection()->fd].ssl;
    typedef Ssl::CertValidationResponse::RecvdErrors::const_iterator SVCRECI;
    for (SVCRECI i = resp.errors.begin(); i != resp.errors.end(); ++i) {
        debugs(83, 7, "Error item: " << i->error_no << " " << i->error_reason);

        assert(i->error_no != SSL_ERROR_NONE);

        if (!errDetails) {
            bool allowed = false;
            if (check) {
                check->sslErrors = new Ssl::CertErrors(Ssl::CertError(i->error_no, i->cert.get(), i->error_depth));
                if (check->fastCheck() == ACCESS_ALLOWED)
                    allowed = true;
            }
            // else the Config.ssl_client.cert_error access list is not defined
            // and the first error will cause the error page

            if (allowed) {
                debugs(83, 3, "bypassing SSL error " << i->error_no << " in " << "buffer");
            } else {
                debugs(83, 5, "confirming SSL error " << i->error_no);
                X509 *brokenCert = i->cert.get();
                Security::CertPointer peerCert(SSL_get_peer_certificate(ssl));
                const char *aReason = i->error_reason.empty() ? NULL : i->error_reason.c_str();
                errDetails = new Ssl::ErrorDetail(i->error_no, peerCert.get(), brokenCert, aReason);
            }
            if (check) {
                delete check->sslErrors;
                check->sslErrors = NULL;
            }
        }

        if (!errs)
            errs = new Ssl::CertErrors(Ssl::CertError(i->error_no, i->cert.get(), i->error_depth));
        else
            errs->push_back_unique(Ssl::CertError(i->error_no, i->cert.get(), i->error_depth));
    }
    if (check)
        delete check;

    return errs;
}

/// A wrapper for Comm::SetSelect() notifications.
void
Ssl::PeerConnector::NegotiateSsl(int, void *data)
{
    PeerConnector *pc = static_cast<PeerConnector*>(data);
    // Use job calls to add done() checks and other job logic/protections.
    CallJobHere(83, 7, pc, Ssl::PeerConnector, negotiateSsl);
}

void
Ssl::PeerConnector::handleNegotiateError(const int ret)
{
    const int fd = serverConnection()->fd;
    unsigned long ssl_lib_error = SSL_ERROR_NONE;
    SSL *ssl = fd_table[fd].ssl;
    const int ssl_error = SSL_get_error(ssl, ret);

    switch (ssl_error) {
    case SSL_ERROR_WANT_READ:
        noteWantRead();
        return;

    case SSL_ERROR_WANT_WRITE:
        noteWantWrite();
        return;

    case SSL_ERROR_SSL:
    case SSL_ERROR_SYSCALL:
        ssl_lib_error = ERR_get_error();
        // proceed to the general error handling code
        break;
    default:
        // no special error handling for all other errors
        break;
    }
    noteSslNegotiationError(ret, ssl_error, ssl_lib_error);
}

void
Ssl::PeerConnector::noteWantRead()
{
    const int fd = serverConnection()->fd;
    SSL *ssl = fd_table[fd].ssl;
    BIO *b = SSL_get_rbio(ssl);
    Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(b->ptr);
    if (srvBio->holdRead()) {
        if (srvBio->gotHello()) {
            if (checkForMissingCertificates())
                return; // Wait to download certificates before proceed.

            srvBio->holdRead(false);
            // Schedule a negotiateSSl to allow openSSL parse received data
            Ssl::PeerConnector::NegotiateSsl(fd, this);
            return;
        } else if (srvBio->gotHelloFailed()) {
            srvBio->holdRead(false);
            debugs(83, DBG_IMPORTANT, "Error parsing SSL Server Hello Message on FD " << fd);
            // Schedule a negotiateSSl to allow openSSL parse received data
            Ssl::PeerConnector::NegotiateSsl(fd, this);
            return;
        }
    }

    setReadTimeout();
    Comm::SetSelect(fd, COMM_SELECT_READ, &NegotiateSsl, this, 0);
}

void
Ssl::PeerConnector::noteWantWrite()
{
    const int fd = serverConnection()->fd;
    Comm::SetSelect(fd, COMM_SELECT_WRITE, &NegotiateSsl, this, 0);
    return;
}

void
Ssl::PeerConnector::noteSslNegotiationError(const int ret, const int ssl_error, const int ssl_lib_error)
{
#ifdef EPROTO
    int sysErrNo = EPROTO;
#else
    int sysErrNo = EACCES;
#endif

    // store/report errno when ssl_error is SSL_ERROR_SYSCALL, ssl_lib_error is 0, and ret is -1
    if (ssl_error == SSL_ERROR_SYSCALL && ret == -1 && ssl_lib_error == 0)
        sysErrNo = errno;

    const int fd = serverConnection()->fd;
    debugs(83, DBG_IMPORTANT, "Error negotiating SSL on FD " << fd <<
           ": " << ERR_error_string(ssl_lib_error, NULL) << " (" <<
           ssl_error << "/" << ret << "/" << errno << ")");

    ErrorState *anErr = NULL;
    if (request != NULL)
        anErr = ErrorState::NewForwarding(ERR_SECURE_CONNECT_FAIL, request.getRaw());
    else
        anErr = new ErrorState(ERR_SECURE_CONNECT_FAIL, Http::scServiceUnavailable, NULL);
    anErr->xerrno = sysErrNo;

    SSL *ssl = fd_table[fd].ssl;
    Ssl::ErrorDetail *errFromFailure = (Ssl::ErrorDetail *)SSL_get_ex_data(ssl, ssl_ex_index_ssl_error_detail);
    if (errFromFailure != NULL) {
        // The errFromFailure is attached to the ssl object
        // and will be released when ssl object destroyed.
        // Copy errFromFailure to a new Ssl::ErrorDetail object
        anErr->detail = new Ssl::ErrorDetail(*errFromFailure);
    } else {
        // server_cert can be NULL here
        X509 *server_cert = SSL_get_peer_certificate(ssl);
        anErr->detail = new Ssl::ErrorDetail(SQUID_ERR_SSL_HANDSHAKE, server_cert, NULL);
        X509_free(server_cert);
    }

    if (ssl_lib_error != SSL_ERROR_NONE)
        anErr->detail->setLibError(ssl_lib_error);

    assert(certErrors == NULL);
    // remember validation errors, if any
    if (Ssl::CertErrors *errs = static_cast<Ssl::CertErrors*>(SSL_get_ex_data(ssl, ssl_ex_index_ssl_errors)))
        certErrors = cbdataReference(errs);

    noteNegotiationDone(anErr);
    bail(anErr);
}

void
Ssl::PeerConnector::bail(ErrorState *error)
{
    Must(error); // or the recepient will not know there was a problem
    Must(callback != NULL);
    CbDialer *dialer = dynamic_cast<CbDialer*>(callback->getDialer());
    Must(dialer);
    dialer->answer().error = error;

    callBack();
    // Our job is done. The callabck recepient will probably close the failed
    // peer connection and try another peer or go direct (if possible). We
    // can close the connection ourselves (our error notification would reach
    // the recepient before the fd-closure notification), but we would rather
    // minimize the number of fd-closure notifications and let the recepient
    // manage the TCP state of the connection.
}

void
Ssl::PeerConnector::callBack()
{
    AsyncCall::Pointer cb = callback;
    // Do this now so that if we throw below, swanSong() assert that we _tried_
    // to call back holds.
    callback = NULL; // this should make done() true

    // remove close handler
    comm_remove_close_handler(serverConnection()->fd, closeHandler);

    CbDialer *dialer = dynamic_cast<CbDialer*>(cb->getDialer());
    Must(dialer);
    dialer->answer().conn = serverConnection();
    ScheduleCallHere(cb);
}

void
Ssl::PeerConnector::swanSong()
{
    // XXX: unregister fd-closure monitoring and CommSetSelect interest, if any
    AsyncJob::swanSong();
    if (callback != NULL) { // paranoid: we have left the caller waiting
        debugs(83, DBG_IMPORTANT, "BUG: Unexpected state while connecting to a cache_peer or origin server");
        ErrorState *anErr = new ErrorState(ERR_GATEWAY_FAILURE, Http::scInternalServerError, request.getRaw());
        bail(anErr);
        assert(!callback);
        return;
    }
}

const char *
Ssl::PeerConnector::status() const
{
    static MemBuf buf;
    buf.reset();

    // TODO: redesign AsyncJob::status() API to avoid this
    // id and stop reason reporting duplication.
    buf.append(" [", 2);
    if (stopReason != NULL) {
        buf.append("Stopped, reason:", 16);
        buf.appendf("%s",stopReason);
    }
    if (serverConn != NULL)
        buf.appendf(" FD %d", serverConn->fd);
    buf.appendf(" %s%u]", id.Prefix, id.value);
    buf.terminate();

    return buf.content();
}

/// CallDialer to allow use Downloader objects within PeerConnector class.
class PeerConnectorCertDownloaderDialer: public CallDialer, public Downloader::CbDialer
{
public:
    typedef void (Ssl::PeerConnector::*Method)(SBuf &object, int status);

    PeerConnectorCertDownloaderDialer(Method method, Ssl::PeerConnector *pc):
        method_(method),
        peerConnector_(pc) {}

    /* CallDialer API */
    virtual bool canDial(AsyncCall &call) { return peerConnector_.valid(); }
    void dial(AsyncCall &call) { ((&(*peerConnector_))->*method_)(object, status); }
    virtual void print(std::ostream &os) const {
        os << '(' << peerConnector_.get() << ", Http Status:" << status << ')';
    }

    Method method_; ///< The Ssl::PeerConnector method to dial
    CbcPointer<Ssl::PeerConnector> peerConnector_; ///< The Ssl::PeerConnector object
};

void
Ssl::PeerConnector::startCertDownloading(SBuf &url)
{
    AsyncCall::Pointer certCallback = asyncCall(81, 4,
                                            "Ssl::PeerConnector::certDownloadingDone",
                                            PeerConnectorCertDownloaderDialer(&Ssl::PeerConnector::certDownloadingDone, this));

    const Downloader *csd = dynamic_cast<const Downloader*>(request->clientConnectionManager.valid());
    MasterXaction *xaction = new MasterXaction;
    Downloader *dl = new Downloader(url, xaction, certCallback, csd ? csd->nestedLevel() + 1 : 1);
    AsyncJob::Start(dl);
}

void
Ssl::PeerConnector::certDownloadingDone(SBuf &obj, int downloadStatus)
{
    certsDownloads++;
    debugs(81, 5, "OK! certificate downloaded, status: " << downloadStatus << " data size: " << obj.length());

    // Get ServerBio from SSL object
    const int fd = serverConnection()->fd;
    SSL *ssl = fd_table[fd].ssl;
    BIO *b = SSL_get_rbio(ssl);
    Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(b->ptr);

    // Parse Certificate. Assume that it is in DER format. Probably we should handle PEM or other formats too
    const unsigned char *raw = (const unsigned char*)obj.rawContent();
    if (X509 *cert = d2i_X509(NULL, &raw, obj.length())) {
        char buffer[1024];
        debugs(81, 5, "Retrieved certificate: " << X509_NAME_oneline(X509_get_subject_name(cert), buffer, 1024));
        const Ssl::X509_STACK_Pointer &certsList = srvBio->serverCertificates();
        if (const char *issuerUri = Ssl::uriOfIssuerIfMissing(cert,  certsList)) {
            urlsOfMissingCerts.push(SBuf(issuerUri));
        }
        Ssl::SSL_add_untrusted_cert(ssl, cert);
    }

    // Check if has uri to donwload and add it to urlsOfMissingCerts
    if (urlsOfMissingCerts.size() && certsDownloads <= MaxCertsDownloads) {
        startCertDownloading(urlsOfMissingCerts.front());
        urlsOfMissingCerts.pop();
        return;
    }

    srvBio->holdRead(false);
    Ssl::PeerConnector::NegotiateSsl(serverConnection()->fd, this);
}

bool
Ssl::PeerConnector::checkForMissingCertificates ()
{
    // Check for nested SSL certificates downloads. For example when the
    // certificate located in an SSL site which requires to download a
    // a missing certificate (... from an SSL site which requires to ...)
    const Downloader *csd = dynamic_cast<const Downloader*>(request->clientConnectionManager.valid());
    if (csd && csd->nestedLevel() >= MaxNestedDownloads)
        return false;

    const int fd = serverConnection()->fd;
    SSL *ssl = fd_table[fd].ssl;
    BIO *b = SSL_get_rbio(ssl);
    Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(b->ptr);
    const Ssl::X509_STACK_Pointer &certs = srvBio->serverCertificates();

    if (certs.get() && sk_X509_num(certs.get())) {
        debugs(83, 5, "SSL server sent " << sk_X509_num(certs.get()) << " certificates");
        Ssl::missingChainCertificatesUrls(urlsOfMissingCerts, certs);
        if (urlsOfMissingCerts.size()) {
            startCertDownloading(urlsOfMissingCerts.front());
            urlsOfMissingCerts.pop();
            return true;
        }
    }

    return false;
}

Security::ContextPtr
Ssl::BlindPeerConnector::getSslContext()
{
    if (const CachePeer *peer = serverConnection()->getPeer()) {
        assert(peer->secure.encryptTransport);
        Security::ContextPtr sslContext(peer->sslContext);
        return sslContext;
    }
    return ::Config.ssl_client.sslContext;
}

SSL *
Ssl::BlindPeerConnector::initializeSsl()
{
    SSL *ssl = Ssl::PeerConnector::initializeSsl();
    if (!ssl)
        return NULL;

    if (const CachePeer *peer = serverConnection()->getPeer()) {
        assert(peer);

        // NP: domain may be a raw-IP but it is now always set
        assert(!peer->secure.sslDomain.isEmpty());

        // const loss is okay here, ssl_ex_index_server is only read and not assigned a destructor
        SBuf *host = new SBuf(peer->secure.sslDomain);
        SSL_set_ex_data(ssl, ssl_ex_index_server, host);

        if (peer->sslSession)
            SSL_set_session(ssl, peer->sslSession);
    } else {
        SBuf *hostName = new SBuf(request->url.host());
        SSL_set_ex_data(ssl, ssl_ex_index_server, (void*)hostName);
    }

    return ssl;
}

void
Ssl::BlindPeerConnector::noteNegotiationDone(ErrorState *error)
{
    if (error) {
        // XXX: forward.cc calls peerConnectSucceeded() after an OK TCP connect but
        // we call peerConnectFailed() if SSL failed afterwards. Is that OK?
        // It is not clear whether we should call peerConnectSucceeded/Failed()
        // based on TCP results, SSL results, or both. And the code is probably not
        // consistent in this aspect across tunnelling and forwarding modules.
        if (CachePeer *p = serverConnection()->getPeer())
            peerConnectFailed(p);
        return;
    }

    const int fd = serverConnection()->fd;
    SSL *ssl = fd_table[fd].ssl;
    if (serverConnection()->getPeer() && !SSL_session_reused(ssl)) {
        if (serverConnection()->getPeer()->sslSession)
            SSL_SESSION_free(serverConnection()->getPeer()->sslSession);

        serverConnection()->getPeer()->sslSession = SSL_get1_session(ssl);
    }
}

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

SSL *
Ssl::PeekingPeerConnector::initializeSsl()
{
    SSL *ssl = Ssl::PeerConnector::initializeSsl();
    if (!ssl)
        return NULL;

    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 (SSL *clientSsl = fd_table[clientConn->fd].ssl) {
            BIO *b = SSL_get_rbio(clientSsl);
            cltBio = static_cast<Ssl::ClientBio *>(b->ptr);
            const Ssl::Bio::sslFeatures &features = cltBio->getFeatures();
            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->getFeatures();
            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)
{
    SSL *ssl = fd_table[serverConnection()->fd].ssl;

    // 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);
                    }
                }
            }
        }
    }

    if (!error) {
        serverCertificateVerified();
        if (splice)
            switchToTunnel(request.getRaw(), clientConn, serverConn);
    }
}

void
Ssl::PeekingPeerConnector::noteWantWrite()
{
    const int fd = serverConnection()->fd;
    SSL *ssl = fd_table[fd].ssl;
    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;
    SSL *ssl = fd_table[fd].ssl;
    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;
        SSL *ssl = fd_table[fd].ssl;
        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;
            SSL *ssl = fd_table[fd].ssl;
            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());
        }
    }
}