/*
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "webrtc/base/win32.h"
#define SECURITY_WIN32
#include <security.h>
#include <schannel.h>
#include <iomanip>
#include <vector>
#include "webrtc/base/common.h"
#include "webrtc/base/logging.h"
#include "webrtc/base/schanneladapter.h"
#include "webrtc/base/sec_buffer.h"
#include "webrtc/base/thread.h"
namespace rtc {
/////////////////////////////////////////////////////////////////////////////
// SChannelAdapter
/////////////////////////////////////////////////////////////////////////////
extern const ConstantLabel SECURITY_ERRORS[];
const ConstantLabel SCHANNEL_BUFFER_TYPES[] = {
KLABEL(SECBUFFER_EMPTY), // 0
KLABEL(SECBUFFER_DATA), // 1
KLABEL(SECBUFFER_TOKEN), // 2
KLABEL(SECBUFFER_PKG_PARAMS), // 3
KLABEL(SECBUFFER_MISSING), // 4
KLABEL(SECBUFFER_EXTRA), // 5
KLABEL(SECBUFFER_STREAM_TRAILER), // 6
KLABEL(SECBUFFER_STREAM_HEADER), // 7
KLABEL(SECBUFFER_MECHLIST), // 11
KLABEL(SECBUFFER_MECHLIST_SIGNATURE), // 12
KLABEL(SECBUFFER_TARGET), // 13
KLABEL(SECBUFFER_CHANNEL_BINDINGS), // 14
LASTLABEL
};
void DescribeBuffer(LoggingSeverity severity, const char* prefix,
const SecBuffer& sb) {
LOG_V(severity)
<< prefix
<< "(" << sb.cbBuffer
<< ", " << FindLabel(sb.BufferType & ~SECBUFFER_ATTRMASK,
SCHANNEL_BUFFER_TYPES)
<< ", " << sb.pvBuffer << ")";
}
void DescribeBuffers(LoggingSeverity severity, const char* prefix,
const SecBufferDesc* sbd) {
if (!LOG_CHECK_LEVEL_V(severity))
return;
LOG_V(severity) << prefix << "(";
for (size_t i=0; i<sbd->cBuffers; ++i) {
DescribeBuffer(severity, " ", sbd->pBuffers[i]);
}
LOG_V(severity) << ")";
}
const ULONG SSL_FLAGS_DEFAULT = ISC_REQ_ALLOCATE_MEMORY
| ISC_REQ_CONFIDENTIALITY
| ISC_REQ_EXTENDED_ERROR
| ISC_REQ_INTEGRITY
| ISC_REQ_REPLAY_DETECT
| ISC_REQ_SEQUENCE_DETECT
| ISC_REQ_STREAM;
//| ISC_REQ_USE_SUPPLIED_CREDS;
typedef std::vector<char> SChannelBuffer;
struct SChannelAdapter::SSLImpl {
CredHandle cred;
CtxtHandle ctx;
bool cred_init, ctx_init;
SChannelBuffer inbuf, outbuf, readable;
SecPkgContext_StreamSizes sizes;
SSLImpl() : cred_init(false), ctx_init(false) { }
};
SChannelAdapter::SChannelAdapter(AsyncSocket* socket)
: SSLAdapter(socket), state_(SSL_NONE),
restartable_(false), signal_close_(false), message_pending_(false),
impl_(new SSLImpl) {
}
SChannelAdapter::~SChannelAdapter() {
Cleanup();
}
int
SChannelAdapter::StartSSL(const char* hostname, bool restartable) {
if (state_ != SSL_NONE)
return ERROR_ALREADY_INITIALIZED;
ssl_host_name_ = hostname;
restartable_ = restartable;
if (socket_->GetState() != Socket::CS_CONNECTED) {
state_ = SSL_WAIT;
return 0;
}
state_ = SSL_CONNECTING;
if (int err = BeginSSL()) {
Error("BeginSSL", err, false);
return err;
}
return 0;
}
int
SChannelAdapter::BeginSSL() {
LOG(LS_VERBOSE) << "BeginSSL: " << ssl_host_name_;
ASSERT(state_ == SSL_CONNECTING);
SECURITY_STATUS ret;
SCHANNEL_CRED sc_cred = { 0 };
sc_cred.dwVersion = SCHANNEL_CRED_VERSION;
//sc_cred.dwMinimumCipherStrength = 128; // Note: use system default
sc_cred.dwFlags = SCH_CRED_NO_DEFAULT_CREDS | SCH_CRED_AUTO_CRED_VALIDATION;
ret = AcquireCredentialsHandle(NULL, UNISP_NAME, SECPKG_CRED_OUTBOUND, NULL,
&sc_cred, NULL, NULL, &impl_->cred, NULL);
if (ret != SEC_E_OK) {
LOG(LS_ERROR) << "AcquireCredentialsHandle error: "
<< ErrorName(ret, SECURITY_ERRORS);
return ret;
}
impl_->cred_init = true;
if (LOG_CHECK_LEVEL(LS_VERBOSE)) {
SecPkgCred_CipherStrengths cipher_strengths = { 0 };
ret = QueryCredentialsAttributes(&impl_->cred,
SECPKG_ATTR_CIPHER_STRENGTHS,
&cipher_strengths);
if (SUCCEEDED(ret)) {
LOG(LS_VERBOSE) << "SChannel cipher strength: "
<< cipher_strengths.dwMinimumCipherStrength << " - "
<< cipher_strengths.dwMaximumCipherStrength;
}
SecPkgCred_SupportedAlgs supported_algs = { 0 };
ret = QueryCredentialsAttributes(&impl_->cred,
SECPKG_ATTR_SUPPORTED_ALGS,
&supported_algs);
if (SUCCEEDED(ret)) {
LOG(LS_VERBOSE) << "SChannel supported algorithms:";
for (DWORD i=0; i<supported_algs.cSupportedAlgs; ++i) {
ALG_ID alg_id = supported_algs.palgSupportedAlgs[i];
PCCRYPT_OID_INFO oinfo = CryptFindOIDInfo(CRYPT_OID_INFO_ALGID_KEY,
&alg_id, 0);
LPCWSTR alg_name = (NULL != oinfo) ? oinfo->pwszName : L"Unknown";
LOG(LS_VERBOSE) << " " << ToUtf8(alg_name) << " (" << alg_id << ")";
}
CSecBufferBase::FreeSSPI(supported_algs.palgSupportedAlgs);
}
}
ULONG flags = SSL_FLAGS_DEFAULT, ret_flags = 0;
if (ignore_bad_cert())
flags |= ISC_REQ_MANUAL_CRED_VALIDATION;
CSecBufferBundle<2, CSecBufferBase::FreeSSPI> sb_out;
ret = InitializeSecurityContextA(&impl_->cred, NULL,
const_cast<char*>(ssl_host_name_.c_str()),
flags, 0, 0, NULL, 0,
&impl_->ctx, sb_out.desc(),
&ret_flags, NULL);
if (SUCCEEDED(ret))
impl_->ctx_init = true;
return ProcessContext(ret, NULL, sb_out.desc());
}
int
SChannelAdapter::ContinueSSL() {
LOG(LS_VERBOSE) << "ContinueSSL";
ASSERT(state_ == SSL_CONNECTING);
SECURITY_STATUS ret;
CSecBufferBundle<2> sb_in;
sb_in[0].BufferType = SECBUFFER_TOKEN;
sb_in[0].cbBuffer = static_cast<unsigned long>(impl_->inbuf.size());
sb_in[0].pvBuffer = &impl_->inbuf[0];
//DescribeBuffers(LS_VERBOSE, "Input Buffer ", sb_in.desc());
ULONG flags = SSL_FLAGS_DEFAULT, ret_flags = 0;
if (ignore_bad_cert())
flags |= ISC_REQ_MANUAL_CRED_VALIDATION;
CSecBufferBundle<2, CSecBufferBase::FreeSSPI> sb_out;
ret = InitializeSecurityContextA(&impl_->cred, &impl_->ctx,
const_cast<char*>(ssl_host_name_.c_str()),
flags, 0, 0, sb_in.desc(), 0,
NULL, sb_out.desc(),
&ret_flags, NULL);
return ProcessContext(ret, sb_in.desc(), sb_out.desc());
}
int
SChannelAdapter::ProcessContext(long int status, _SecBufferDesc* sbd_in,
_SecBufferDesc* sbd_out) {
if (status != SEC_E_OK && status != SEC_I_CONTINUE_NEEDED &&
status != SEC_E_INCOMPLETE_MESSAGE) {
LOG(LS_ERROR)
<< "InitializeSecurityContext error: "
<< ErrorName(status, SECURITY_ERRORS);
}
//if (sbd_in)
// DescribeBuffers(LS_VERBOSE, "Input Buffer ", sbd_in);
//if (sbd_out)
// DescribeBuffers(LS_VERBOSE, "Output Buffer ", sbd_out);
if (status == SEC_E_INCOMPLETE_MESSAGE) {
// Wait for more input from server.
return Flush();
}
if (FAILED(status)) {
// We can't continue. Common errors:
// SEC_E_CERT_EXPIRED - Typically, this means the computer clock is wrong.
return status;
}
// Note: we check both input and output buffers for SECBUFFER_EXTRA.
// Experience shows it appearing in the input, but the documentation claims
// it should appear in the output.
size_t extra = 0;
if (sbd_in) {
for (size_t i=0; i<sbd_in->cBuffers; ++i) {
SecBuffer& buffer = sbd_in->pBuffers[i];
if (buffer.BufferType == SECBUFFER_EXTRA) {
extra += buffer.cbBuffer;
}
}
}
if (sbd_out) {
for (size_t i=0; i<sbd_out->cBuffers; ++i) {
SecBuffer& buffer = sbd_out->pBuffers[i];
if (buffer.BufferType == SECBUFFER_EXTRA) {
extra += buffer.cbBuffer;
} else if (buffer.BufferType == SECBUFFER_TOKEN) {
impl_->outbuf.insert(impl_->outbuf.end(),
reinterpret_cast<char*>(buffer.pvBuffer),
reinterpret_cast<char*>(buffer.pvBuffer) + buffer.cbBuffer);
}
}
}
if (extra) {
ASSERT(extra <= impl_->inbuf.size());
size_t consumed = impl_->inbuf.size() - extra;
memmove(&impl_->inbuf[0], &impl_->inbuf[consumed], extra);
impl_->inbuf.resize(extra);
} else {
impl_->inbuf.clear();
}
if (SEC_I_CONTINUE_NEEDED == status) {
// Send data to server and wait for response.
// Note: ContinueSSL will result in a Flush, anyway.
return impl_->inbuf.empty() ? Flush() : ContinueSSL();
}
if (SEC_E_OK == status) {
LOG(LS_VERBOSE) << "QueryContextAttributes";
status = QueryContextAttributes(&impl_->ctx, SECPKG_ATTR_STREAM_SIZES,
&impl_->sizes);
if (FAILED(status)) {
LOG(LS_ERROR) << "QueryContextAttributes error: "
<< ErrorName(status, SECURITY_ERRORS);
return status;
}
state_ = SSL_CONNECTED;
if (int err = DecryptData()) {
return err;
} else if (int err = Flush()) {
return err;
} else {
// If we decrypted any data, queue up a notification here
PostEvent();
// Signal our connectedness
AsyncSocketAdapter::OnConnectEvent(this);
}
return 0;
}
if (SEC_I_INCOMPLETE_CREDENTIALS == status) {
// We don't support client authentication in schannel.
return status;
}
// We don't expect any other codes
ASSERT(false);
return status;
}
int
SChannelAdapter::DecryptData() {
SChannelBuffer& inbuf = impl_->inbuf;
SChannelBuffer& readable = impl_->readable;
while (!inbuf.empty()) {
CSecBufferBundle<4> in_buf;
in_buf[0].BufferType = SECBUFFER_DATA;
in_buf[0].cbBuffer = static_cast<unsigned long>(inbuf.size());
in_buf[0].pvBuffer = &inbuf[0];
//DescribeBuffers(LS_VERBOSE, "Decrypt In ", in_buf.desc());
SECURITY_STATUS status = DecryptMessage(&impl_->ctx, in_buf.desc(), 0, 0);
//DescribeBuffers(LS_VERBOSE, "Decrypt Out ", in_buf.desc());
// Note: We are explicitly treating SEC_E_OK, SEC_I_CONTEXT_EXPIRED, and
// any other successful results as continue.
if (SUCCEEDED(status)) {
size_t data_len = 0, extra_len = 0;
for (size_t i=0; i<in_buf.desc()->cBuffers; ++i) {
if (in_buf[i].BufferType == SECBUFFER_DATA) {
data_len += in_buf[i].cbBuffer;
readable.insert(readable.end(),
reinterpret_cast<char*>(in_buf[i].pvBuffer),
reinterpret_cast<char*>(in_buf[i].pvBuffer) + in_buf[i].cbBuffer);
} else if (in_buf[i].BufferType == SECBUFFER_EXTRA) {
extra_len += in_buf[i].cbBuffer;
}
}
// There is a bug on Win2K where SEC_I_CONTEXT_EXPIRED is misclassified.
if ((data_len == 0) && (inbuf[0] == 0x15)) {
status = SEC_I_CONTEXT_EXPIRED;
}
if (extra_len) {
size_t consumed = inbuf.size() - extra_len;
memmove(&inbuf[0], &inbuf[consumed], extra_len);
inbuf.resize(extra_len);
} else {
inbuf.clear();
}
// TODO: Handle SEC_I_CONTEXT_EXPIRED to do clean shutdown
if (status != SEC_E_OK) {
LOG(LS_INFO) << "DecryptMessage returned continuation code: "
<< ErrorName(status, SECURITY_ERRORS);
}
continue;
}
if (status == SEC_E_INCOMPLETE_MESSAGE) {
break;
} else {
return status;
}
}
return 0;
}
void
SChannelAdapter::Cleanup() {
if (impl_->ctx_init)
DeleteSecurityContext(&impl_->ctx);
if (impl_->cred_init)
FreeCredentialsHandle(&impl_->cred);
delete impl_;
}
void
SChannelAdapter::PostEvent() {
// Check if there's anything notable to signal
if (impl_->readable.empty() && !signal_close_)
return;
// Only one post in the queue at a time
if (message_pending_)
return;
if (Thread* thread = Thread::Current()) {
message_pending_ = true;
thread->Post(this);
} else {
LOG(LS_ERROR) << "No thread context available for SChannelAdapter";
ASSERT(false);
}
}
void
SChannelAdapter::Error(const char* context, int err, bool signal) {
LOG(LS_WARNING) << "SChannelAdapter::Error("
<< context << ", "
<< ErrorName(err, SECURITY_ERRORS) << ")";
state_ = SSL_ERROR;
SetError(err);
if (signal)
AsyncSocketAdapter::OnCloseEvent(this, err);
}
int
SChannelAdapter::Read() {
char buffer[4096];
SChannelBuffer& inbuf = impl_->inbuf;
while (true) {
int ret = AsyncSocketAdapter::Recv(buffer, sizeof(buffer));
if (ret > 0) {
inbuf.insert(inbuf.end(), buffer, buffer + ret);
} else if (GetError() == EWOULDBLOCK) {
return 0; // Blocking
} else {
return GetError();
}
}
}
int
SChannelAdapter::Flush() {
int result = 0;
size_t pos = 0;
SChannelBuffer& outbuf = impl_->outbuf;
while (pos < outbuf.size()) {
int sent = AsyncSocketAdapter::Send(&outbuf[pos], outbuf.size() - pos);
if (sent > 0) {
pos += sent;
} else if (GetError() == EWOULDBLOCK) {
break; // Blocking
} else {
result = GetError();
break;
}
}
if (int remainder = static_cast<int>(outbuf.size() - pos)) {
memmove(&outbuf[0], &outbuf[pos], remainder);
outbuf.resize(remainder);
} else {
outbuf.clear();
}
return result;
}
//
// AsyncSocket Implementation
//
int
SChannelAdapter::Send(const void* pv, size_t cb) {
switch (state_) {
case SSL_NONE:
return AsyncSocketAdapter::Send(pv, cb);
case SSL_WAIT:
case SSL_CONNECTING:
SetError(EWOULDBLOCK);
return SOCKET_ERROR;
case SSL_CONNECTED:
break;
case SSL_ERROR:
default:
return SOCKET_ERROR;
}
size_t written = 0;
SChannelBuffer& outbuf = impl_->outbuf;
while (written < cb) {
const size_t encrypt_len = std::min<size_t>(cb - written,
impl_->sizes.cbMaximumMessage);
CSecBufferBundle<4> out_buf;
out_buf[0].BufferType = SECBUFFER_STREAM_HEADER;
out_buf[0].cbBuffer = impl_->sizes.cbHeader;
out_buf[1].BufferType = SECBUFFER_DATA;
out_buf[1].cbBuffer = static_cast<unsigned long>(encrypt_len);
out_buf[2].BufferType = SECBUFFER_STREAM_TRAILER;
out_buf[2].cbBuffer = impl_->sizes.cbTrailer;
size_t packet_len = out_buf[0].cbBuffer
+ out_buf[1].cbBuffer
+ out_buf[2].cbBuffer;
SChannelBuffer message;
message.resize(packet_len);
out_buf[0].pvBuffer = &message[0];
out_buf[1].pvBuffer = &message[out_buf[0].cbBuffer];
out_buf[2].pvBuffer = &message[out_buf[0].cbBuffer + out_buf[1].cbBuffer];
memcpy(out_buf[1].pvBuffer,
static_cast<const char*>(pv) + written,
encrypt_len);
//DescribeBuffers(LS_VERBOSE, "Encrypt In ", out_buf.desc());
SECURITY_STATUS res = EncryptMessage(&impl_->ctx, 0, out_buf.desc(), 0);
//DescribeBuffers(LS_VERBOSE, "Encrypt Out ", out_buf.desc());
if (FAILED(res)) {
Error("EncryptMessage", res, false);
return SOCKET_ERROR;
}
// We assume that the header and data segments do not change length,
// or else encrypting the concatenated packet in-place is wrong.
ASSERT(out_buf[0].cbBuffer == impl_->sizes.cbHeader);
ASSERT(out_buf[1].cbBuffer == static_cast<unsigned long>(encrypt_len));
// However, the length of the trailer may change due to padding.
ASSERT(out_buf[2].cbBuffer <= impl_->sizes.cbTrailer);
packet_len = out_buf[0].cbBuffer
+ out_buf[1].cbBuffer
+ out_buf[2].cbBuffer;
written += encrypt_len;
outbuf.insert(outbuf.end(), &message[0], &message[packet_len-1]+1);
}
if (int err = Flush()) {
state_ = SSL_ERROR;
SetError(err);
return SOCKET_ERROR;
}
return static_cast<int>(written);
}
int
SChannelAdapter::Recv(void* pv, size_t cb) {
switch (state_) {
case SSL_NONE:
return AsyncSocketAdapter::Recv(pv, cb);
case SSL_WAIT:
case SSL_CONNECTING:
SetError(EWOULDBLOCK);
return SOCKET_ERROR;
case SSL_CONNECTED:
break;
case SSL_ERROR:
default:
return SOCKET_ERROR;
}
SChannelBuffer& readable = impl_->readable;
if (readable.empty()) {
SetError(EWOULDBLOCK);
return SOCKET_ERROR;
}
size_t read = _min(cb, readable.size());
memcpy(pv, &readable[0], read);
if (size_t remaining = readable.size() - read) {
memmove(&readable[0], &readable[read], remaining);
readable.resize(remaining);
} else {
readable.clear();
}
PostEvent();
return static_cast<int>(read);
}
int
SChannelAdapter::Close() {
if (!impl_->readable.empty()) {
LOG(WARNING) << "SChannelAdapter::Close with readable data";
// Note: this isn't strictly an error, but we're using it temporarily to
// track bugs.
//ASSERT(false);
}
if (state_ == SSL_CONNECTED) {
DWORD token = SCHANNEL_SHUTDOWN;
CSecBufferBundle<1> sb_in;
sb_in[0].BufferType = SECBUFFER_TOKEN;
sb_in[0].cbBuffer = sizeof(token);
sb_in[0].pvBuffer = &token;
ApplyControlToken(&impl_->ctx, sb_in.desc());
// TODO: In theory, to do a nice shutdown, we need to begin shutdown
// negotiation with more calls to InitializeSecurityContext. Since the
// socket api doesn't support nice shutdown at this point, we don't bother.
}
Cleanup();
impl_ = new SSLImpl;
state_ = restartable_ ? SSL_WAIT : SSL_NONE;
signal_close_ = false;
message_pending_ = false;
return AsyncSocketAdapter::Close();
}
Socket::ConnState
SChannelAdapter::GetState() const {
if (signal_close_)
return CS_CONNECTED;
ConnState state = socket_->GetState();
if ((state == CS_CONNECTED)
&& ((state_ == SSL_WAIT) || (state_ == SSL_CONNECTING)))
state = CS_CONNECTING;
return state;
}
void
SChannelAdapter::OnConnectEvent(AsyncSocket* socket) {
LOG(LS_VERBOSE) << "SChannelAdapter::OnConnectEvent";
if (state_ != SSL_WAIT) {
ASSERT(state_ == SSL_NONE);
AsyncSocketAdapter::OnConnectEvent(socket);
return;
}
state_ = SSL_CONNECTING;
if (int err = BeginSSL()) {
Error("BeginSSL", err);
}
}
void
SChannelAdapter::OnReadEvent(AsyncSocket* socket) {
if (state_ == SSL_NONE) {
AsyncSocketAdapter::OnReadEvent(socket);
return;
}
if (int err = Read()) {
Error("Read", err);
return;
}
if (impl_->inbuf.empty())
return;
if (state_ == SSL_CONNECTED) {
if (int err = DecryptData()) {
Error("DecryptData", err);
} else if (!impl_->readable.empty()) {
AsyncSocketAdapter::OnReadEvent(this);
}
} else if (state_ == SSL_CONNECTING) {
if (int err = ContinueSSL()) {
Error("ContinueSSL", err);
}
}
}
void
SChannelAdapter::OnWriteEvent(AsyncSocket* socket) {
if (state_ == SSL_NONE) {
AsyncSocketAdapter::OnWriteEvent(socket);
return;
}
if (int err = Flush()) {
Error("Flush", err);
return;
}
// See if we have more data to write
if (!impl_->outbuf.empty())
return;
// Buffer is empty, submit notification
if (state_ == SSL_CONNECTED) {
AsyncSocketAdapter::OnWriteEvent(socket);
}
}
void
SChannelAdapter::OnCloseEvent(AsyncSocket* socket, int err) {
if ((state_ == SSL_NONE) || impl_->readable.empty()) {
AsyncSocketAdapter::OnCloseEvent(socket, err);
return;
}
// If readable is non-empty, then we have a pending Message
// that will allow us to signal close (eventually).
signal_close_ = true;
}
void
SChannelAdapter::OnMessage(Message* pmsg) {
if (!message_pending_)
return; // This occurs when socket is closed
message_pending_ = false;
if (!impl_->readable.empty()) {
AsyncSocketAdapter::OnReadEvent(this);
} else if (signal_close_) {
signal_close_ = false;
AsyncSocketAdapter::OnCloseEvent(this, 0); // TODO: cache this error?
}
}
} // namespace rtc