Bug 1961: pt1: URL handling redesign

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

/*
 * 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 "errorpage.h"
#include "fde.h"
#include "globals.h"
#include "HttpRequest.h"
#include "neighbors.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"
#include "SquidConfig.h"

CBDATA_NAMESPACED_CLASS_INIT(Ssl, PeerConnector);

Ssl::PeerConnector::PeerConnector(
    HttpRequestPointer &aRequest,
    const Comm::ConnectionPointer &aServerConn,
    AsyncCall::Pointer &aCallback):
    AsyncJob("Ssl::PeerConnector"),
    request(aRequest),
    serverConn(aServerConn),
    callback(aCallback)
{
    // if this throws, the caller's cb dialer is not our CbDialer
    Must(dynamic_cast<CbDialer*>(callback->getDialer()));
}

Ssl::PeerConnector::~PeerConnector()
{
    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();
        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;
}

void
Ssl::PeerConnector::initializeSsl()
{
    SSL *ssl;
    SSL_CTX *sslContext = NULL;
    const CachePeer *peer = serverConnection()->getPeer();
    const int fd = serverConnection()->fd;

    if (peer) {
        assert(peer->use_ssl);
        sslContext = peer->sslContext;
    } else {
        sslContext = ::Config.ssl_client.sslContext;
    }

    assert(sslContext);

    if ((ssl = SSL_new(sslContext)) == NULL) {
        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));
        bail(anErr);
        return;
    }

    SSL_set_fd(ssl, fd);

    if (peer) {
        if (peer->ssldomain)
            SSL_set_ex_data(ssl, ssl_ex_index_server, peer->ssldomain);

#if NOT_YET

        else if (peer->name)
            SSL_set_ex_data(ssl, ssl_ex_index_server, peer->name);

#endif

        else
            SSL_set_ex_data(ssl, ssl_ex_index_server, peer->host);

        if (peer->sslSession)
            SSL_set_session(ssl, peer->sslSession);

    } else {
        // 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 char *hostname = request->GetHost();
        const bool hostnameIsIp = request->GetHostIsNumeric();
        const bool isConnectRequest = request->clientConnectionManager.valid() &&
                                      !request->clientConnectionManager->port->flags.isIntercepted();
        if (!request->flags.sslPeek || isConnectRequest)
            SSL_set_ex_data(ssl, ssl_ex_index_server, (void*)hostname);

        // Use SNI TLS extension only when we connect directly
        // to the origin server and we know the server host name.
        if (!hostnameIsIp)
            Ssl::setClientSNI(ssl, hostname);
    }

    // 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);
        }
    }

    // store peeked cert to check SQUID_X509_V_ERR_CERT_CHANGE
    X509 *peeked_cert;
    if (request->clientConnectionManager.valid() &&
            request->clientConnectionManager->serverBump() &&
            (peeked_cert = request->clientConnectionManager->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);
    }

    fd_table[fd].ssl = ssl;
    fd_table[fd].read_method = &ssl_read_method;
    fd_table[fd].write_method = &ssl_write_method;
}

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 (request->clientConnectionManager.valid()) {
        // remember the server certificate from the ErrorDetail object
        if (Ssl::ServerBump *serverBump = request->clientConnectionManager->serverBump()) {
            serverBump->serverCert.reset(SSL_get_peer_certificate(ssl));

            // remember validation errors, if any
            if (Ssl::CertErrors *errs = static_cast<Ssl::CertErrors *>(SSL_get_ex_data(ssl, ssl_ex_index_ssl_errors)))
                serverBump->sslErrors = cbdataReference(errs);
        }
    }

    if (serverConnection()->getPeer() && !SSL_session_reused(ssl)) {
        if (serverConnection()->getPeer()->sslSession)
            SSL_SESSION_free(serverConnection()->getPeer()->sslSession);

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

    if (Ssl::TheConfig.ssl_crt_validator) {
        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->GetHost();
        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.");
            Ssl::CertValidationHelper::GetInstance()->sslSubmit(validationRequest, sslCrtvdHandleReplyWrapper, this);
            return;
        } 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());
            bail(anErr);
            if (serverConnection()->getPeer()) {
                peerConnectFailed(serverConnection()->getPeer());
            }
            serverConn->close();
            return;
        }
    }

    callBack();
}

void
Ssl::PeerConnector::sslCrtvdHandleReplyWrapper(void *data, Ssl::CertValidationResponse const &validationResponse)
{
    Ssl::PeerConnector *connector = (Ssl::PeerConnector *)(data);
    connector->sslCrtvdHandleReply(validationResponse);
}

void
Ssl::PeerConnector::sslCrtvdHandleReply(Ssl::CertValidationResponse const &validationResponse)
{
    Ssl::CertErrors *errs = NULL;
    Ssl::ErrorDetail *errDetails = NULL;
    bool validatorFailed = false;
    if (!Comm::IsConnOpen(serverConnection())) {
        return;
    }

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

    if (validationResponse.resultCode == HelperReply::Error)
        errs = sslCrtvdCheckForErrors(validationResponse, errDetails);
    else if (validationResponse.resultCode != HelperReply::Okay)
        validatorFailed = true;

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

    ErrorState *anErr = NULL;
    if (validatorFailed) {
        anErr = new ErrorState(ERR_GATEWAY_FAILURE, Http::scInternalServerError, request.getRaw());
    }  else {

        // Check the list error with
        if (errDetails && request->clientConnectionManager.valid()) {
            // remember the server certificate from the ErrorDetail object
            if (Ssl::ServerBump *serverBump = request->clientConnectionManager->serverBump()) {
                // remember validation errors, if any
                if (errs) {
                    if (serverBump->sslErrors)
                        cbdataReferenceDone(serverBump->sslErrors);
                    serverBump->sslErrors = cbdataReference(errs);
                }
            }
        }

        anErr =  new ErrorState(ERR_SECURE_CONNECT_FAIL, Http::scServiceUnavailable, request.getRaw());
        anErr->detail = errDetails;
        /*anErr->xerrno= Should preserved*/
    }

    bail(anErr);
    if (serverConnection()->getPeer()) {
        peerConnectFailed(serverConnection()->getPeer());
    }
    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()));
                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();
                Ssl::X509_Pointer 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()));
        else
            errs->push_back_unique(Ssl::CertError(i->error_no, i->cert.get()));
    }
    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;
    int ssl_error = SSL_get_error(ssl, ret);

#ifdef EPROTO
        int sysErrNo = EPROTO;
#else
        int sysErrNo = EACCES;
#endif

        switch (ssl_error) {

        case SSL_ERROR_WANT_READ:
            Comm::SetSelect(fd, COMM_SELECT_READ, &NegotiateSsl, this, 0);
            return;

        case SSL_ERROR_WANT_WRITE:
            Comm::SetSelect(fd, COMM_SELECT_WRITE, &NegotiateSsl, this, 0);
            return;

        case SSL_ERROR_SSL:
        case SSL_ERROR_SYSCALL:
            ssl_lib_error = ERR_get_error();

            // 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;

            debugs(83, DBG_IMPORTANT, "Error negotiating SSL on FD " << fd <<
                   ": " << ERR_error_string(ssl_lib_error, NULL) << " (" <<
                   ssl_error << "/" << ret << "/" << errno << ")");

            break; // proceed to the general error handling code

        default:
            break; // no special error handling for all other errors
        }

    ErrorState *const anErr = ErrorState::NewForwarding(ERR_SECURE_CONNECT_FAIL, request.getRaw());
    anErr->xerrno = sysErrNo;

    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);

    if (request->clientConnectionManager.valid()) {
        // remember the server certificate from the ErrorDetail object
        if (Ssl::ServerBump *serverBump = request->clientConnectionManager->serverBump()) {
            serverBump->serverCert.resetAndLock(anErr->detail->peerCert());

            // remember validation errors, if any
            if (Ssl::CertErrors *errs = static_cast<Ssl::CertErrors*>(SSL_get_ex_data(ssl, ssl_ex_index_ssl_errors)))
                serverBump->sslErrors = cbdataReference(errs);
        }

        // 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 = anErr->detail->peerCert()) {
                if (const char *name = Ssl::CommonHostName(srvX509)) {
                    request->SetHost(name);
                    debugs(83, 3, HERE << "reset request host: " << name);
                }
            }
        }
    }

    bail(anErr);
}

void
Ssl::PeerConnector::bail(ErrorState *error)
{
    Must(error); // or the recepient will not know there was a problem

    // 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);

    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();
    assert(!callback); // paranoid: we have not left the caller waiting
}

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.Printf("Stopped, reason:");
        buf.Printf("%s",stopReason);
    }
    if (serverConn != NULL)
        buf.Printf(" FD %d", serverConn->fd);
    buf.Printf(" %s%u]", id.Prefix, id.value);
    buf.terminate();

    return buf.content();
}

/* PeerConnectorAnswer */

Ssl::PeerConnectorAnswer::~PeerConnectorAnswer()
{
    delete error.get();
}

std::ostream &
operator <<(std::ostream &os, const Ssl::PeerConnectorAnswer &answer)
{
    return os << answer.conn << ", " << answer.error;
}