src/ssl/PeekingPeerConnector.cc

   1 /*
   2  * Copyright (C) 1996-2019 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 /* DEBUG: section 83    SSL-Bump Server/Peer negotiation */
  10
  11 #include "squid.h"
  12 #include "acl/FilledChecklist.h"
  13 #include "client_side.h"
  14 #include "errorpage.h"
  15 #include "fde.h"
  16 #include "http/Stream.h"
  17 #include "HttpRequest.h"
  18 #include "security/NegotiationHistory.h"
  19 #include "SquidConfig.h"
  20 #include "ssl/bio.h"
  21 #include "ssl/PeekingPeerConnector.h"
  22 #include "ssl/ServerBump.h"
  23
  24 CBDATA_NAMESPACED_CLASS_INIT(Ssl, PeekingPeerConnector);
  25
  26 void switchToTunnel(HttpRequest *request, Comm::ConnectionPointer & clientConn, Comm::ConnectionPointer &srvConn);
  27
  28 void
  29 Ssl::PeekingPeerConnector::cbCheckForPeekAndSpliceDone(Acl::Answer answer, void *data)
  30 {
  31     Ssl::PeekingPeerConnector *peerConnect = (Ssl::PeekingPeerConnector *) data;
  32     // Use job calls to add done() checks and other job logic/protections.
  33     CallJobHere1(83, 7, CbcPointer<PeekingPeerConnector>(peerConnect), Ssl::PeekingPeerConnector, checkForPeekAndSpliceDone, answer);
  34 }
  35
  36 void
  37 Ssl::PeekingPeerConnector::checkForPeekAndSpliceDone(Acl::Answer answer)
  38 {
  39     const Ssl::BumpMode finalAction = answer.allowed() ?
  40                                       static_cast<Ssl::BumpMode>(answer.kind):
  41                                       checkForPeekAndSpliceGuess();
  42     checkForPeekAndSpliceMatched(finalAction);
  43 }
  44
  45 void
  46 Ssl::PeekingPeerConnector::checkForPeekAndSplice()
  47 {
  48     // Mark Step3 of bumping
  49     if (request->clientConnectionManager.valid()) {
  50         if (Ssl::ServerBump *serverBump = request->clientConnectionManager->serverBump()) {
  51             serverBump->step = Ssl::bumpStep3;
  52         }
  53     }
  54
  55     handleServerCertificate();
  56
  57     ACLFilledChecklist *acl_checklist = new ACLFilledChecklist(
  58         ::Config.accessList.ssl_bump,
  59         request.getRaw(), NULL);
  60     acl_checklist->al = al;
  61     acl_checklist->banAction(Acl::Answer(ACCESS_ALLOWED, Ssl::bumpNone));
  62     acl_checklist->banAction(Acl::Answer(ACCESS_ALLOWED, Ssl::bumpPeek));
  63     acl_checklist->banAction(Acl::Answer(ACCESS_ALLOWED, Ssl::bumpStare));
  64     acl_checklist->banAction(Acl::Answer(ACCESS_ALLOWED, Ssl::bumpClientFirst));
  65     acl_checklist->banAction(Acl::Answer(ACCESS_ALLOWED, Ssl::bumpServerFirst));
  66     Security::SessionPointer session(fd_table[serverConn->fd].ssl);
  67     BIO *b = SSL_get_rbio(session.get());
  68     Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(BIO_get_data(b));
  69     if (!srvBio->canSplice())
  70         acl_checklist->banAction(Acl::Answer(ACCESS_ALLOWED, Ssl::bumpSplice));
  71     if (!srvBio->canBump())
  72         acl_checklist->banAction(Acl::Answer(ACCESS_ALLOWED, Ssl::bumpBump));
  73     acl_checklist->syncAle(request.getRaw(), nullptr);
  74     acl_checklist->nonBlockingCheck(Ssl::PeekingPeerConnector::cbCheckForPeekAndSpliceDone, this);
  75 }
  76
  77 void
  78 Ssl::PeekingPeerConnector::checkForPeekAndSpliceMatched(const Ssl::BumpMode action)
  79 {
  80     Security::SessionPointer session(fd_table[serverConn->fd].ssl);
  81     BIO *b = SSL_get_rbio(session.get());
  82     Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(BIO_get_data(b));
  83     debugs(83,5, "Will check for peek and splice on FD " << serverConn->fd);
  84
  85     Ssl::BumpMode finalAction = action;
  86     Must(finalAction == Ssl::bumpSplice || finalAction == Ssl::bumpBump || finalAction == Ssl::bumpTerminate);
  87     // Record final decision
  88     if (request->clientConnectionManager.valid()) {
  89         request->clientConnectionManager->sslBumpMode = finalAction;
  90         request->clientConnectionManager->serverBump()->act.step3 = finalAction;
  91     }
  92     al->ssl.bumpMode = finalAction;
  93
  94     if (finalAction == Ssl::bumpTerminate) {
  95         serverConn->close();
  96         clientConn->close();
  97     } else if (finalAction != Ssl::bumpSplice) {
  98         //Allow write, proceed with the connection
  99         srvBio->holdWrite(false);
 100         srvBio->recordInput(false);
 101         debugs(83,5, "Retry the fwdNegotiateSSL on FD " << serverConn->fd);
 102         Security::PeerConnector::noteWantWrite();
 103     } else {
 104         splice = true;
 105         // Ssl Negotiation stops here. Last SSL checks for valid certificates
 106         // and if done, switch to tunnel mode
 107         if (sslFinalized()) {
 108             debugs(83,5, "Abort NegotiateSSL on FD " << serverConn->fd << " and splice the connection");
 109             callBack();
 110         }
 111     }
 112 }
 113
 114 Ssl::BumpMode
 115 Ssl::PeekingPeerConnector::checkForPeekAndSpliceGuess() const
 116 {
 117     if (const ConnStateData *csd = request->clientConnectionManager.valid()) {
 118         const Ssl::BumpMode currentMode = csd->sslBumpMode;
 119         if (currentMode == Ssl::bumpStare) {
 120             debugs(83,5, "default to bumping after staring");
 121             return Ssl::bumpBump;
 122         }
 123         debugs(83,5, "default to splicing after " << currentMode);
 124     } else {
 125         debugs(83,3, "default to splicing due to missing info");
 126     }
 127
 128     return Ssl::bumpSplice;
 129 }
 130
 131 Security::ContextPointer
 132 Ssl::PeekingPeerConnector::getTlsContext()
 133 {
 134     return ::Config.ssl_client.sslContext;
 135 }
 136
 137 bool
 138 Ssl::PeekingPeerConnector::initialize(Security::SessionPointer &serverSession)
 139 {
 140     if (!Security::PeerConnector::initialize(serverSession))
 141         return false;
 142
 143     if (ConnStateData *csd = request->clientConnectionManager.valid()) {
 144
 145         // client connection is required in the case we need to splice
 146         // or terminate client and server connections
 147         assert(clientConn != NULL);
 148         SBuf *hostName = NULL;
 149
 150         //Enable Status_request TLS extension, required to bump some clients
 151         SSL_set_tlsext_status_type(serverSession.get(), TLSEXT_STATUSTYPE_ocsp);
 152
 153         const Security::TlsDetails::Pointer details = csd->tlsParser.details;
 154         if (details && !details->serverName.isEmpty())
 155             hostName = new SBuf(details->serverName);
 156
 157         if (!hostName) {
 158             // While we are peeking at the certificate, we may not know the server
 159             // name that the client will request (after interception or CONNECT)
 160             // unless it was the CONNECT request with a user-typed address.
 161             const bool isConnectRequest = !csd->port->flags.isIntercepted();
 162             if (!request->flags.sslPeek || isConnectRequest)
 163                 hostName = new SBuf(request->url.host());
 164         }
 165
 166         if (hostName)
 167             SSL_set_ex_data(serverSession.get(), ssl_ex_index_server, (void*)hostName);
 168
 169         Must(!csd->serverBump() || csd->serverBump()->step <= Ssl::bumpStep2);
 170         if (csd->sslBumpMode == Ssl::bumpPeek || csd->sslBumpMode == Ssl::bumpStare) {
 171             auto clientSession = fd_table[clientConn->fd].ssl.get();
 172             Must(clientSession);
 173             BIO *bc = SSL_get_rbio(clientSession);
 174             Ssl::ClientBio *cltBio = static_cast<Ssl::ClientBio *>(BIO_get_data(bc));
 175             Must(cltBio);
 176             if (details && details->tlsVersion.protocol != AnyP::PROTO_NONE)
 177                 applyTlsDetailsToSSL(serverSession.get(), details, csd->sslBumpMode);
 178
 179             BIO *b = SSL_get_rbio(serverSession.get());
 180             Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(BIO_get_data(b));
 181             Must(srvBio);
 182             // inherit client features such as TLS version and SNI
 183             srvBio->setClientFeatures(details, cltBio->rBufData());
 184             srvBio->recordInput(true);
 185             srvBio->mode(csd->sslBumpMode);
 186         } else {
 187             // Set client SSL options
 188             ::Security::ProxyOutgoingConfig.updateSessionOptions(serverSession);
 189
 190             const bool redirected = request->flags.redirected && ::Config.onoff.redir_rewrites_host;
 191             const char *sniServer = (!hostName || redirected) ?
 192                                     request->url.host() :
 193                                     hostName->c_str();
 194             if (sniServer)
 195                 setClientSNI(serverSession.get(), sniServer);
 196         }
 197
 198         if (Ssl::ServerBump *serverBump = csd->serverBump()) {
 199             serverBump->attachServerSession(serverSession);
 200             // store peeked cert to check SQUID_X509_V_ERR_CERT_CHANGE
 201             if (X509 *peeked_cert = serverBump->serverCert.get()) {
 202                 X509_up_ref(peeked_cert);
 203                 SSL_set_ex_data(serverSession.get(), ssl_ex_index_ssl_peeked_cert, peeked_cert);
 204             }
 205         }
 206     }
 207
 208     return true;
 209 }
 210
 211 void
 212 Ssl::PeekingPeerConnector::noteNegotiationDone(ErrorState *error)
 213 {
 214     // Check the list error with
 215     if (!request->clientConnectionManager.valid() || !fd_table[serverConnection()->fd].ssl)
 216         return;
 217
 218     // remember the server certificate from the ErrorDetail object
 219     if (Ssl::ServerBump *serverBump = request->clientConnectionManager->serverBump()) {
 220         if (!serverBump->serverCert.get()) {
 221             // remember the server certificate from the ErrorDetail object
 222             if (error && error->detail && error->detail->peerCert())
 223                 serverBump->serverCert.resetAndLock(error->detail->peerCert());
 224             else {
 225                 handleServerCertificate();
 226             }
 227         }
 228
 229         if (error) {
 230             // For intercepted connections, set the host name to the server
 231             // certificate CN. Otherwise, we just hope that CONNECT is using
 232             // a user-entered address (a host name or a user-entered IP).
 233             const bool isConnectRequest = !request->clientConnectionManager->port->flags.isIntercepted();
 234             if (request->flags.sslPeek && !isConnectRequest) {
 235                 if (X509 *srvX509 = serverBump->serverCert.get()) {
 236                     if (const char *name = Ssl::CommonHostName(srvX509)) {
 237                         request->url.host(name);
 238                         debugs(83, 3, "reset request host: " << name);
 239                     }
 240                 }
 241             }
 242         }
 243     }
 244
 245     if (!error) {
 246         serverCertificateVerified();
 247         if (splice) {
 248             switchToTunnel(request.getRaw(), clientConn, serverConn);
 249             tunnelInsteadOfNegotiating();
 250         }
 251     }
 252 }
 253
 254 void
 255 Ssl::PeekingPeerConnector::noteWantWrite()
 256 {
 257     const int fd = serverConnection()->fd;
 258     Security::SessionPointer session(fd_table[fd].ssl);
 259     BIO *b = SSL_get_rbio(session.get());
 260     Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(BIO_get_data(b));
 261
 262     if ((srvBio->bumpMode() == Ssl::bumpPeek || srvBio->bumpMode() == Ssl::bumpStare) && srvBio->holdWrite()) {
 263         debugs(81, 3, "hold write on SSL connection on FD " << fd);
 264         checkForPeekAndSplice();
 265         return;
 266     }
 267
 268     Security::PeerConnector::noteWantWrite();
 269 }
 270
 271 void
 272 Ssl::PeekingPeerConnector::noteNegotiationError(const int result, const int ssl_error, const int ssl_lib_error)
 273 {
 274     const int fd = serverConnection()->fd;
 275     Security::SessionPointer session(fd_table[fd].ssl);
 276     BIO *b = SSL_get_rbio(session.get());
 277     Ssl::ServerBio *srvBio = static_cast<Ssl::ServerBio *>(BIO_get_data(b));
 278
 279     // In Peek mode, the ClientHello message sent to the server. If the
 280     // server resuming a previous (spliced) SSL session with the client,
 281     // then probably we are here because local SSL object does not know
 282     // anything about the session being resumed.
 283     //
 284     if (srvBio->bumpMode() == Ssl::bumpPeek && (resumingSession = srvBio->resumingSession())) {
 285         // we currently splice all resumed sessions unconditionally
 286         // if (const bool spliceResumed = true) {
 287         bypassCertValidator();
 288         checkForPeekAndSpliceMatched(Ssl::bumpSplice);
 289         return;
 290         // } // else fall through to find a matching ssl_bump action (with limited info)
 291     }
 292
 293     // If we are in peek-and-splice mode and still we did not write to
 294     // server yet, try to see if we should splice.
 295     // In this case the connection can be saved.
 296     // If the checklist decision is do not splice a new error will
 297     // occur in the next SSL_connect call, and we will fail again.
 298     // Abort on certificate validation errors to avoid splicing and
 299     // thus hiding them.
 300     // Abort if no certificate found probably because of malformed or
 301     // unsupported server Hello message (TODO: make configurable).
 302     if (!SSL_get_ex_data(session.get(), ssl_ex_index_ssl_error_detail) &&
 303             (srvBio->bumpMode() == Ssl::bumpPeek  || srvBio->bumpMode() == Ssl::bumpStare) && srvBio->holdWrite()) {
 304         Security::CertPointer serverCert(SSL_get_peer_certificate(session.get()));
 305         if (serverCert) {
 306             debugs(81, 3, "Error ("  << Security::ErrorString(ssl_lib_error) <<  ") but, hold write on SSL connection on FD " << fd);
 307             checkForPeekAndSplice();
 308             return;
 309         }
 310     }
 311
 312     // else call parent noteNegotiationError to produce an error page
 313     Security::PeerConnector::noteNegotiationError(result, ssl_error, ssl_lib_error);
 314 }
 315
 316 void
 317 Ssl::PeekingPeerConnector::handleServerCertificate()
 318 {
 319     if (serverCertificateHandled)
 320         return;
 321
 322     if (ConnStateData *csd = request->clientConnectionManager.valid()) {
 323         const int fd = serverConnection()->fd;
 324         Security::SessionPointer session(fd_table[fd].ssl);
 325         Security::CertPointer serverCert(SSL_get_peer_certificate(session.get()));
 326         if (!serverCert)
 327             return;
 328
 329         serverCertificateHandled = true;
 330
 331         // remember the server certificate for later use
 332         if (Ssl::ServerBump *serverBump = csd->serverBump()) {
 333             serverBump->serverCert = std::move(serverCert);
 334         }
 335     }
 336 }
 337
 338 void
 339 Ssl::PeekingPeerConnector::serverCertificateVerified()
 340 {
 341     if (ConnStateData *csd = request->clientConnectionManager.valid()) {
 342         Security::CertPointer serverCert;
 343         if(Ssl::ServerBump *serverBump = csd->serverBump())
 344             serverCert.resetAndLock(serverBump->serverCert.get());
 345         else {
 346             const int fd = serverConnection()->fd;
 347             Security::SessionPointer session(fd_table[fd].ssl);
 348             serverCert.resetWithoutLocking(SSL_get_peer_certificate(session.get()));
 349         }
 350         if (serverCert) {
 351             csd->resetSslCommonName(Ssl::CommonHostName(serverCert.get()));
 352             debugs(83, 5, "HTTPS server CN: " << csd->sslCommonName() <<
 353                    " bumped: " << *serverConnection());
 354         }
 355     }
 356 }
 357
 358 void
 359 Ssl::PeekingPeerConnector::tunnelInsteadOfNegotiating()
 360 {
 361     Must(callback != NULL);
 362     CbDialer *dialer = dynamic_cast<CbDialer*>(callback->getDialer());
 363     Must(dialer);
 364     dialer->answer().tunneled = true;
 365     debugs(83, 5, "The SSL negotiation with server aborted");
 366 }
 367