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      1 /*
      2  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #include "webrtc/base/win32.h"
     12 #define SECURITY_WIN32
     13 #include <security.h>
     14 #include <schannel.h>
     15 
     16 #include <iomanip>
     17 #include <vector>
     18 
     19 #include "webrtc/base/common.h"
     20 #include "webrtc/base/logging.h"
     21 #include "webrtc/base/schanneladapter.h"
     22 #include "webrtc/base/sec_buffer.h"
     23 #include "webrtc/base/thread.h"
     24 
     25 namespace rtc {
     26 
     27 /////////////////////////////////////////////////////////////////////////////
     28 // SChannelAdapter
     29 /////////////////////////////////////////////////////////////////////////////
     30 
     31 extern const ConstantLabel SECURITY_ERRORS[];
     32 
     33 const ConstantLabel SCHANNEL_BUFFER_TYPES[] = {
     34   KLABEL(SECBUFFER_EMPTY),              //  0
     35   KLABEL(SECBUFFER_DATA),               //  1
     36   KLABEL(SECBUFFER_TOKEN),              //  2
     37   KLABEL(SECBUFFER_PKG_PARAMS),         //  3
     38   KLABEL(SECBUFFER_MISSING),            //  4
     39   KLABEL(SECBUFFER_EXTRA),              //  5
     40   KLABEL(SECBUFFER_STREAM_TRAILER),     //  6
     41   KLABEL(SECBUFFER_STREAM_HEADER),      //  7
     42   KLABEL(SECBUFFER_MECHLIST),           // 11
     43   KLABEL(SECBUFFER_MECHLIST_SIGNATURE), // 12
     44   KLABEL(SECBUFFER_TARGET),             // 13
     45   KLABEL(SECBUFFER_CHANNEL_BINDINGS),   // 14
     46   LASTLABEL
     47 };
     48 
     49 void DescribeBuffer(LoggingSeverity severity, const char* prefix,
     50                     const SecBuffer& sb) {
     51   LOG_V(severity)
     52     << prefix
     53     << "(" << sb.cbBuffer
     54     << ", " << FindLabel(sb.BufferType & ~SECBUFFER_ATTRMASK,
     55                           SCHANNEL_BUFFER_TYPES)
     56     << ", " << sb.pvBuffer << ")";
     57 }
     58 
     59 void DescribeBuffers(LoggingSeverity severity, const char* prefix,
     60                      const SecBufferDesc* sbd) {
     61   if (!LOG_CHECK_LEVEL_V(severity))
     62     return;
     63   LOG_V(severity) << prefix << "(";
     64   for (size_t i=0; i<sbd->cBuffers; ++i) {
     65     DescribeBuffer(severity, "  ", sbd->pBuffers[i]);
     66   }
     67   LOG_V(severity) << ")";
     68 }
     69 
     70 const ULONG SSL_FLAGS_DEFAULT = ISC_REQ_ALLOCATE_MEMORY
     71                               | ISC_REQ_CONFIDENTIALITY
     72                               | ISC_REQ_EXTENDED_ERROR
     73                               | ISC_REQ_INTEGRITY
     74                               | ISC_REQ_REPLAY_DETECT
     75                               | ISC_REQ_SEQUENCE_DETECT
     76                               | ISC_REQ_STREAM;
     77                               //| ISC_REQ_USE_SUPPLIED_CREDS;
     78 
     79 typedef std::vector<char> SChannelBuffer;
     80 
     81 struct SChannelAdapter::SSLImpl {
     82   CredHandle cred;
     83   CtxtHandle ctx;
     84   bool cred_init, ctx_init;
     85   SChannelBuffer inbuf, outbuf, readable;
     86   SecPkgContext_StreamSizes sizes;
     87 
     88   SSLImpl() : cred_init(false), ctx_init(false) { }
     89 };
     90 
     91 SChannelAdapter::SChannelAdapter(AsyncSocket* socket)
     92   : SSLAdapter(socket), state_(SSL_NONE),
     93     restartable_(false), signal_close_(false), message_pending_(false),
     94     impl_(new SSLImpl) {
     95 }
     96 
     97 SChannelAdapter::~SChannelAdapter() {
     98   Cleanup();
     99 }
    100 
    101 int
    102 SChannelAdapter::StartSSL(const char* hostname, bool restartable) {
    103   if (state_ != SSL_NONE)
    104     return ERROR_ALREADY_INITIALIZED;
    105 
    106   ssl_host_name_ = hostname;
    107   restartable_ = restartable;
    108 
    109   if (socket_->GetState() != Socket::CS_CONNECTED) {
    110     state_ = SSL_WAIT;
    111     return 0;
    112   }
    113 
    114   state_ = SSL_CONNECTING;
    115   if (int err = BeginSSL()) {
    116     Error("BeginSSL", err, false);
    117     return err;
    118   }
    119 
    120   return 0;
    121 }
    122 
    123 int
    124 SChannelAdapter::BeginSSL() {
    125   LOG(LS_VERBOSE) << "BeginSSL: " << ssl_host_name_;
    126   ASSERT(state_ == SSL_CONNECTING);
    127 
    128   SECURITY_STATUS ret;
    129 
    130   SCHANNEL_CRED sc_cred = { 0 };
    131   sc_cred.dwVersion = SCHANNEL_CRED_VERSION;
    132   //sc_cred.dwMinimumCipherStrength = 128; // Note: use system default
    133   sc_cred.dwFlags = SCH_CRED_NO_DEFAULT_CREDS | SCH_CRED_AUTO_CRED_VALIDATION;
    134 
    135   ret = AcquireCredentialsHandle(NULL, UNISP_NAME, SECPKG_CRED_OUTBOUND, NULL,
    136                                  &sc_cred, NULL, NULL, &impl_->cred, NULL);
    137   if (ret != SEC_E_OK) {
    138     LOG(LS_ERROR) << "AcquireCredentialsHandle error: "
    139                   << ErrorName(ret, SECURITY_ERRORS);
    140     return ret;
    141   }
    142   impl_->cred_init = true;
    143 
    144   if (LOG_CHECK_LEVEL(LS_VERBOSE)) {
    145     SecPkgCred_CipherStrengths cipher_strengths = { 0 };
    146     ret = QueryCredentialsAttributes(&impl_->cred,
    147                                      SECPKG_ATTR_CIPHER_STRENGTHS,
    148                                      &cipher_strengths);
    149     if (SUCCEEDED(ret)) {
    150       LOG(LS_VERBOSE) << "SChannel cipher strength: "
    151                   << cipher_strengths.dwMinimumCipherStrength << " - "
    152                   << cipher_strengths.dwMaximumCipherStrength;
    153     }
    154 
    155     SecPkgCred_SupportedAlgs supported_algs = { 0 };
    156     ret = QueryCredentialsAttributes(&impl_->cred,
    157                                      SECPKG_ATTR_SUPPORTED_ALGS,
    158                                      &supported_algs);
    159     if (SUCCEEDED(ret)) {
    160       LOG(LS_VERBOSE) << "SChannel supported algorithms:";
    161       for (DWORD i=0; i<supported_algs.cSupportedAlgs; ++i) {
    162         ALG_ID alg_id = supported_algs.palgSupportedAlgs[i];
    163         PCCRYPT_OID_INFO oinfo = CryptFindOIDInfo(CRYPT_OID_INFO_ALGID_KEY,
    164                                                   &alg_id, 0);
    165         LPCWSTR alg_name = (NULL != oinfo) ? oinfo->pwszName : L"Unknown";
    166         LOG(LS_VERBOSE) << "  " << ToUtf8(alg_name) << " (" << alg_id << ")";
    167       }
    168       CSecBufferBase::FreeSSPI(supported_algs.palgSupportedAlgs);
    169     }
    170   }
    171 
    172   ULONG flags = SSL_FLAGS_DEFAULT, ret_flags = 0;
    173   if (ignore_bad_cert())
    174     flags |= ISC_REQ_MANUAL_CRED_VALIDATION;
    175 
    176   CSecBufferBundle<2, CSecBufferBase::FreeSSPI> sb_out;
    177   ret = InitializeSecurityContextA(&impl_->cred, NULL,
    178                                    const_cast<char*>(ssl_host_name_.c_str()),
    179                                    flags, 0, 0, NULL, 0,
    180                                    &impl_->ctx, sb_out.desc(),
    181                                    &ret_flags, NULL);
    182   if (SUCCEEDED(ret))
    183     impl_->ctx_init = true;
    184   return ProcessContext(ret, NULL, sb_out.desc());
    185 }
    186 
    187 int
    188 SChannelAdapter::ContinueSSL() {
    189   LOG(LS_VERBOSE) << "ContinueSSL";
    190   ASSERT(state_ == SSL_CONNECTING);
    191 
    192   SECURITY_STATUS ret;
    193 
    194   CSecBufferBundle<2> sb_in;
    195   sb_in[0].BufferType = SECBUFFER_TOKEN;
    196   sb_in[0].cbBuffer = static_cast<unsigned long>(impl_->inbuf.size());
    197   sb_in[0].pvBuffer = &impl_->inbuf[0];
    198   //DescribeBuffers(LS_VERBOSE, "Input Buffer ", sb_in.desc());
    199 
    200   ULONG flags = SSL_FLAGS_DEFAULT, ret_flags = 0;
    201   if (ignore_bad_cert())
    202     flags |= ISC_REQ_MANUAL_CRED_VALIDATION;
    203 
    204   CSecBufferBundle<2, CSecBufferBase::FreeSSPI> sb_out;
    205   ret = InitializeSecurityContextA(&impl_->cred, &impl_->ctx,
    206                                    const_cast<char*>(ssl_host_name_.c_str()),
    207                                    flags, 0, 0, sb_in.desc(), 0,
    208                                    NULL, sb_out.desc(),
    209                                    &ret_flags, NULL);
    210   return ProcessContext(ret, sb_in.desc(), sb_out.desc());
    211 }
    212 
    213 int
    214 SChannelAdapter::ProcessContext(long int status, _SecBufferDesc* sbd_in,
    215                                 _SecBufferDesc* sbd_out) {
    216   if (status != SEC_E_OK && status != SEC_I_CONTINUE_NEEDED &&
    217       status != SEC_E_INCOMPLETE_MESSAGE) {
    218     LOG(LS_ERROR)
    219       << "InitializeSecurityContext error: "
    220       << ErrorName(status, SECURITY_ERRORS);
    221   }
    222   //if (sbd_in)
    223   //  DescribeBuffers(LS_VERBOSE, "Input Buffer ", sbd_in);
    224   //if (sbd_out)
    225   //  DescribeBuffers(LS_VERBOSE, "Output Buffer ", sbd_out);
    226 
    227   if (status == SEC_E_INCOMPLETE_MESSAGE) {
    228     // Wait for more input from server.
    229     return Flush();
    230   }
    231 
    232   if (FAILED(status)) {
    233     // We can't continue.  Common errors:
    234     // SEC_E_CERT_EXPIRED - Typically, this means the computer clock is wrong.
    235     return status;
    236   }
    237 
    238   // Note: we check both input and output buffers for SECBUFFER_EXTRA.
    239   // Experience shows it appearing in the input, but the documentation claims
    240   // it should appear in the output.
    241   size_t extra = 0;
    242   if (sbd_in) {
    243     for (size_t i=0; i<sbd_in->cBuffers; ++i) {
    244       SecBuffer& buffer = sbd_in->pBuffers[i];
    245       if (buffer.BufferType == SECBUFFER_EXTRA) {
    246         extra += buffer.cbBuffer;
    247       }
    248     }
    249   }
    250   if (sbd_out) {
    251     for (size_t i=0; i<sbd_out->cBuffers; ++i) {
    252       SecBuffer& buffer = sbd_out->pBuffers[i];
    253       if (buffer.BufferType == SECBUFFER_EXTRA) {
    254         extra += buffer.cbBuffer;
    255       } else if (buffer.BufferType == SECBUFFER_TOKEN) {
    256         impl_->outbuf.insert(impl_->outbuf.end(),
    257           reinterpret_cast<char*>(buffer.pvBuffer),
    258           reinterpret_cast<char*>(buffer.pvBuffer) + buffer.cbBuffer);
    259       }
    260     }
    261   }
    262 
    263   if (extra) {
    264     ASSERT(extra <= impl_->inbuf.size());
    265     size_t consumed = impl_->inbuf.size() - extra;
    266     memmove(&impl_->inbuf[0], &impl_->inbuf[consumed], extra);
    267     impl_->inbuf.resize(extra);
    268   } else {
    269     impl_->inbuf.clear();
    270   }
    271 
    272   if (SEC_I_CONTINUE_NEEDED == status) {
    273     // Send data to server and wait for response.
    274     // Note: ContinueSSL will result in a Flush, anyway.
    275     return impl_->inbuf.empty() ? Flush() : ContinueSSL();
    276   }
    277 
    278   if (SEC_E_OK == status) {
    279     LOG(LS_VERBOSE) << "QueryContextAttributes";
    280     status = QueryContextAttributes(&impl_->ctx, SECPKG_ATTR_STREAM_SIZES,
    281                                     &impl_->sizes);
    282     if (FAILED(status)) {
    283       LOG(LS_ERROR) << "QueryContextAttributes error: "
    284                     << ErrorName(status, SECURITY_ERRORS);
    285       return status;
    286     }
    287 
    288     state_ = SSL_CONNECTED;
    289 
    290     if (int err = DecryptData()) {
    291       return err;
    292     } else if (int err = Flush()) {
    293       return err;
    294     } else {
    295       // If we decrypted any data, queue up a notification here
    296       PostEvent();
    297       // Signal our connectedness
    298       AsyncSocketAdapter::OnConnectEvent(this);
    299     }
    300     return 0;
    301   }
    302 
    303   if (SEC_I_INCOMPLETE_CREDENTIALS == status) {
    304     // We don't support client authentication in schannel.
    305     return status;
    306   }
    307 
    308   // We don't expect any other codes
    309   ASSERT(false);
    310   return status;
    311 }
    312 
    313 int
    314 SChannelAdapter::DecryptData() {
    315   SChannelBuffer& inbuf = impl_->inbuf;
    316   SChannelBuffer& readable = impl_->readable;
    317 
    318   while (!inbuf.empty()) {
    319     CSecBufferBundle<4> in_buf;
    320     in_buf[0].BufferType = SECBUFFER_DATA;
    321     in_buf[0].cbBuffer = static_cast<unsigned long>(inbuf.size());
    322     in_buf[0].pvBuffer = &inbuf[0];
    323 
    324     //DescribeBuffers(LS_VERBOSE, "Decrypt In ", in_buf.desc());
    325     SECURITY_STATUS status = DecryptMessage(&impl_->ctx, in_buf.desc(), 0, 0);
    326     //DescribeBuffers(LS_VERBOSE, "Decrypt Out ", in_buf.desc());
    327 
    328     // Note: We are explicitly treating SEC_E_OK, SEC_I_CONTEXT_EXPIRED, and
    329     // any other successful results as continue.
    330     if (SUCCEEDED(status)) {
    331       size_t data_len = 0, extra_len = 0;
    332       for (size_t i=0; i<in_buf.desc()->cBuffers; ++i) {
    333         if (in_buf[i].BufferType == SECBUFFER_DATA) {
    334           data_len += in_buf[i].cbBuffer;
    335           readable.insert(readable.end(),
    336             reinterpret_cast<char*>(in_buf[i].pvBuffer),
    337             reinterpret_cast<char*>(in_buf[i].pvBuffer) + in_buf[i].cbBuffer);
    338         } else if (in_buf[i].BufferType == SECBUFFER_EXTRA) {
    339           extra_len += in_buf[i].cbBuffer;
    340         }
    341       }
    342       // There is a bug on Win2K where SEC_I_CONTEXT_EXPIRED is misclassified.
    343       if ((data_len == 0) && (inbuf[0] == 0x15)) {
    344         status = SEC_I_CONTEXT_EXPIRED;
    345       }
    346       if (extra_len) {
    347         size_t consumed = inbuf.size() - extra_len;
    348         memmove(&inbuf[0], &inbuf[consumed], extra_len);
    349         inbuf.resize(extra_len);
    350       } else {
    351         inbuf.clear();
    352       }
    353       // TODO: Handle SEC_I_CONTEXT_EXPIRED to do clean shutdown
    354       if (status != SEC_E_OK) {
    355         LOG(LS_INFO) << "DecryptMessage returned continuation code: "
    356                       << ErrorName(status, SECURITY_ERRORS);
    357       }
    358       continue;
    359     }
    360 
    361     if (status == SEC_E_INCOMPLETE_MESSAGE) {
    362       break;
    363     } else {
    364       return status;
    365     }
    366   }
    367 
    368   return 0;
    369 }
    370 
    371 void
    372 SChannelAdapter::Cleanup() {
    373   if (impl_->ctx_init)
    374     DeleteSecurityContext(&impl_->ctx);
    375   if (impl_->cred_init)
    376     FreeCredentialsHandle(&impl_->cred);
    377   delete impl_;
    378 }
    379 
    380 void
    381 SChannelAdapter::PostEvent() {
    382   // Check if there's anything notable to signal
    383   if (impl_->readable.empty() && !signal_close_)
    384     return;
    385 
    386   // Only one post in the queue at a time
    387   if (message_pending_)
    388     return;
    389 
    390   if (Thread* thread = Thread::Current()) {
    391     message_pending_ = true;
    392     thread->Post(this);
    393   } else {
    394     LOG(LS_ERROR) << "No thread context available for SChannelAdapter";
    395     ASSERT(false);
    396   }
    397 }
    398 
    399 void
    400 SChannelAdapter::Error(const char* context, int err, bool signal) {
    401   LOG(LS_WARNING) << "SChannelAdapter::Error("
    402                   << context << ", "
    403                   << ErrorName(err, SECURITY_ERRORS) << ")";
    404   state_ = SSL_ERROR;
    405   SetError(err);
    406   if (signal)
    407     AsyncSocketAdapter::OnCloseEvent(this, err);
    408 }
    409 
    410 int
    411 SChannelAdapter::Read() {
    412   char buffer[4096];
    413   SChannelBuffer& inbuf = impl_->inbuf;
    414   while (true) {
    415     int ret = AsyncSocketAdapter::Recv(buffer, sizeof(buffer));
    416     if (ret > 0) {
    417       inbuf.insert(inbuf.end(), buffer, buffer + ret);
    418     } else if (GetError() == EWOULDBLOCK) {
    419       return 0;  // Blocking
    420     } else {
    421       return GetError();
    422     }
    423   }
    424 }
    425 
    426 int
    427 SChannelAdapter::Flush() {
    428   int result = 0;
    429   size_t pos = 0;
    430   SChannelBuffer& outbuf = impl_->outbuf;
    431   while (pos < outbuf.size()) {
    432     int sent = AsyncSocketAdapter::Send(&outbuf[pos], outbuf.size() - pos);
    433     if (sent > 0) {
    434       pos += sent;
    435     } else if (GetError() == EWOULDBLOCK) {
    436       break;  // Blocking
    437     } else {
    438       result = GetError();
    439       break;
    440     }
    441   }
    442   if (int remainder = static_cast<int>(outbuf.size() - pos)) {
    443     memmove(&outbuf[0], &outbuf[pos], remainder);
    444     outbuf.resize(remainder);
    445   } else {
    446     outbuf.clear();
    447   }
    448   return result;
    449 }
    450 
    451 //
    452 // AsyncSocket Implementation
    453 //
    454 
    455 int
    456 SChannelAdapter::Send(const void* pv, size_t cb) {
    457   switch (state_) {
    458   case SSL_NONE:
    459     return AsyncSocketAdapter::Send(pv, cb);
    460 
    461   case SSL_WAIT:
    462   case SSL_CONNECTING:
    463     SetError(EWOULDBLOCK);
    464     return SOCKET_ERROR;
    465 
    466   case SSL_CONNECTED:
    467     break;
    468 
    469   case SSL_ERROR:
    470   default:
    471     return SOCKET_ERROR;
    472   }
    473 
    474   size_t written = 0;
    475   SChannelBuffer& outbuf = impl_->outbuf;
    476   while (written < cb) {
    477     const size_t encrypt_len = std::min<size_t>(cb - written,
    478                                                 impl_->sizes.cbMaximumMessage);
    479 
    480     CSecBufferBundle<4> out_buf;
    481     out_buf[0].BufferType = SECBUFFER_STREAM_HEADER;
    482     out_buf[0].cbBuffer = impl_->sizes.cbHeader;
    483     out_buf[1].BufferType = SECBUFFER_DATA;
    484     out_buf[1].cbBuffer = static_cast<unsigned long>(encrypt_len);
    485     out_buf[2].BufferType = SECBUFFER_STREAM_TRAILER;
    486     out_buf[2].cbBuffer = impl_->sizes.cbTrailer;
    487 
    488     size_t packet_len = out_buf[0].cbBuffer
    489                       + out_buf[1].cbBuffer
    490                       + out_buf[2].cbBuffer;
    491 
    492     SChannelBuffer message;
    493     message.resize(packet_len);
    494     out_buf[0].pvBuffer = &message[0];
    495     out_buf[1].pvBuffer = &message[out_buf[0].cbBuffer];
    496     out_buf[2].pvBuffer = &message[out_buf[0].cbBuffer + out_buf[1].cbBuffer];
    497 
    498     memcpy(out_buf[1].pvBuffer,
    499            static_cast<const char*>(pv) + written,
    500            encrypt_len);
    501 
    502     //DescribeBuffers(LS_VERBOSE, "Encrypt In ", out_buf.desc());
    503     SECURITY_STATUS res = EncryptMessage(&impl_->ctx, 0, out_buf.desc(), 0);
    504     //DescribeBuffers(LS_VERBOSE, "Encrypt Out ", out_buf.desc());
    505 
    506     if (FAILED(res)) {
    507       Error("EncryptMessage", res, false);
    508       return SOCKET_ERROR;
    509     }
    510 
    511     // We assume that the header and data segments do not change length,
    512     // or else encrypting the concatenated packet in-place is wrong.
    513     ASSERT(out_buf[0].cbBuffer == impl_->sizes.cbHeader);
    514     ASSERT(out_buf[1].cbBuffer == static_cast<unsigned long>(encrypt_len));
    515 
    516     // However, the length of the trailer may change due to padding.
    517     ASSERT(out_buf[2].cbBuffer <= impl_->sizes.cbTrailer);
    518 
    519     packet_len = out_buf[0].cbBuffer
    520                + out_buf[1].cbBuffer
    521                + out_buf[2].cbBuffer;
    522 
    523     written += encrypt_len;
    524     outbuf.insert(outbuf.end(), &message[0], &message[packet_len-1]+1);
    525   }
    526 
    527   if (int err = Flush()) {
    528     state_ = SSL_ERROR;
    529     SetError(err);
    530     return SOCKET_ERROR;
    531   }
    532 
    533   return static_cast<int>(written);
    534 }
    535 
    536 int
    537 SChannelAdapter::Recv(void* pv, size_t cb) {
    538   switch (state_) {
    539   case SSL_NONE:
    540     return AsyncSocketAdapter::Recv(pv, cb);
    541 
    542   case SSL_WAIT:
    543   case SSL_CONNECTING:
    544     SetError(EWOULDBLOCK);
    545     return SOCKET_ERROR;
    546 
    547   case SSL_CONNECTED:
    548     break;
    549 
    550   case SSL_ERROR:
    551   default:
    552     return SOCKET_ERROR;
    553   }
    554 
    555   SChannelBuffer& readable = impl_->readable;
    556   if (readable.empty()) {
    557     SetError(EWOULDBLOCK);
    558     return SOCKET_ERROR;
    559   }
    560   size_t read = _min(cb, readable.size());
    561   memcpy(pv, &readable[0], read);
    562   if (size_t remaining = readable.size() - read) {
    563     memmove(&readable[0], &readable[read], remaining);
    564     readable.resize(remaining);
    565   } else {
    566     readable.clear();
    567   }
    568 
    569   PostEvent();
    570   return static_cast<int>(read);
    571 }
    572 
    573 int
    574 SChannelAdapter::Close() {
    575   if (!impl_->readable.empty()) {
    576     LOG(WARNING) << "SChannelAdapter::Close with readable data";
    577     // Note: this isn't strictly an error, but we're using it temporarily to
    578     // track bugs.
    579     //ASSERT(false);
    580   }
    581   if (state_ == SSL_CONNECTED) {
    582     DWORD token = SCHANNEL_SHUTDOWN;
    583     CSecBufferBundle<1> sb_in;
    584     sb_in[0].BufferType = SECBUFFER_TOKEN;
    585     sb_in[0].cbBuffer = sizeof(token);
    586     sb_in[0].pvBuffer = &token;
    587     ApplyControlToken(&impl_->ctx, sb_in.desc());
    588     // TODO: In theory, to do a nice shutdown, we need to begin shutdown
    589     // negotiation with more calls to InitializeSecurityContext.  Since the
    590     // socket api doesn't support nice shutdown at this point, we don't bother.
    591   }
    592   Cleanup();
    593   impl_ = new SSLImpl;
    594   state_ = restartable_ ? SSL_WAIT : SSL_NONE;
    595   signal_close_ = false;
    596   message_pending_ = false;
    597   return AsyncSocketAdapter::Close();
    598 }
    599 
    600 Socket::ConnState
    601 SChannelAdapter::GetState() const {
    602   if (signal_close_)
    603     return CS_CONNECTED;
    604   ConnState state = socket_->GetState();
    605   if ((state == CS_CONNECTED)
    606       && ((state_ == SSL_WAIT) || (state_ == SSL_CONNECTING)))
    607     state = CS_CONNECTING;
    608   return state;
    609 }
    610 
    611 void
    612 SChannelAdapter::OnConnectEvent(AsyncSocket* socket) {
    613   LOG(LS_VERBOSE) << "SChannelAdapter::OnConnectEvent";
    614   if (state_ != SSL_WAIT) {
    615     ASSERT(state_ == SSL_NONE);
    616     AsyncSocketAdapter::OnConnectEvent(socket);
    617     return;
    618   }
    619 
    620   state_ = SSL_CONNECTING;
    621   if (int err = BeginSSL()) {
    622     Error("BeginSSL", err);
    623   }
    624 }
    625 
    626 void
    627 SChannelAdapter::OnReadEvent(AsyncSocket* socket) {
    628   if (state_ == SSL_NONE) {
    629     AsyncSocketAdapter::OnReadEvent(socket);
    630     return;
    631   }
    632 
    633   if (int err = Read()) {
    634     Error("Read", err);
    635     return;
    636   }
    637 
    638   if (impl_->inbuf.empty())
    639     return;
    640 
    641   if (state_ == SSL_CONNECTED) {
    642     if (int err = DecryptData()) {
    643       Error("DecryptData", err);
    644     } else if (!impl_->readable.empty()) {
    645       AsyncSocketAdapter::OnReadEvent(this);
    646     }
    647   } else if (state_ == SSL_CONNECTING) {
    648     if (int err = ContinueSSL()) {
    649       Error("ContinueSSL", err);
    650     }
    651   }
    652 }
    653 
    654 void
    655 SChannelAdapter::OnWriteEvent(AsyncSocket* socket) {
    656   if (state_ == SSL_NONE) {
    657     AsyncSocketAdapter::OnWriteEvent(socket);
    658     return;
    659   }
    660 
    661   if (int err = Flush()) {
    662     Error("Flush", err);
    663     return;
    664   }
    665 
    666   // See if we have more data to write
    667   if (!impl_->outbuf.empty())
    668     return;
    669 
    670   // Buffer is empty, submit notification
    671   if (state_ == SSL_CONNECTED) {
    672     AsyncSocketAdapter::OnWriteEvent(socket);
    673   }
    674 }
    675 
    676 void
    677 SChannelAdapter::OnCloseEvent(AsyncSocket* socket, int err) {
    678   if ((state_ == SSL_NONE) || impl_->readable.empty()) {
    679     AsyncSocketAdapter::OnCloseEvent(socket, err);
    680     return;
    681   }
    682 
    683   // If readable is non-empty, then we have a pending Message
    684   // that will allow us to signal close (eventually).
    685   signal_close_ = true;
    686 }
    687 
    688 void
    689 SChannelAdapter::OnMessage(Message* pmsg) {
    690   if (!message_pending_)
    691     return;  // This occurs when socket is closed
    692 
    693   message_pending_ = false;
    694   if (!impl_->readable.empty()) {
    695     AsyncSocketAdapter::OnReadEvent(this);
    696   } else if (signal_close_) {
    697     signal_close_ = false;
    698     AsyncSocketAdapter::OnCloseEvent(this, 0); // TODO: cache this error?
    699   }
    700 }
    701 
    702 } // namespace rtc
    703