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src: in-source comments and minor TLS cleanups

Renamed some internal C++ methods and properties for consistency, and
commented SSL I/O.

- Rename waiting_new_session_ after is_waiting_new_session(), instead of
  using reverse naming (new_session_wait_), and change "waiting" to
  "awaiting".
- Make TLSWrap::ClearIn() return void, the value is never used.
- Fix a getTicketKeys() cut-n-paste error. Since it doesn't use the
  arguments, remove them from the js wrapper.
- Remove call of setTicketKeys(getTicketKeys()), its a no-op.

PR-URL: #25713
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
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sam-github authored and addaleax committed Jan 16, 2019
1 parent 09a1085 commit 6d9af41aef7ed554cb68eb5a4b96bec441ca2e7b
Showing with 84 additions and 39 deletions.
  1. +2 −4 lib/_tls_wrap.js
  2. +3 −2 src/node_crypto.cc
  3. +3 −3 src/node_crypto.h
  4. +6 −5 src/node_crypto_bio.h
  5. +3 −0 src/node_crypto_clienthello.h
  6. +1 −1 src/stream_wrap.cc
  7. +43 −17 src/tls_wrap.cc
  8. +23 −7 src/tls_wrap.h
@@ -998,8 +998,6 @@ Server.prototype.setSecureContext = function(options) {
if (options.ticketKeys) {
this.ticketKeys = options.ticketKeys;
this.setTicketKeys(this.ticketKeys);
} else {
this.setTicketKeys(this.getTicketKeys());
}
};

@@ -1016,8 +1014,8 @@ Server.prototype._setServerData = function(data) {
};


Server.prototype.getTicketKeys = function getTicketKeys(keys) {
return this._sharedCreds.context.getTicketKeys(keys);
Server.prototype.getTicketKeys = function getTicketKeys() {
return this._sharedCreds.context.getTicketKeys();
};


@@ -1505,7 +1505,7 @@ int SSLWrap<Base>::NewSessionCallback(SSL* s, SSL_SESSION* sess) {
reinterpret_cast<const char*>(session_id_data),
session_id_length).ToLocalChecked();
Local<Value> argv[] = { session_id, session };
w->new_session_wait_ = true;
w->awaiting_new_session_ = true;
w->MakeCallback(env->onnewsession_string(), arraysize(argv), argv);

return 0;
@@ -2101,6 +2101,7 @@ void SSLWrap<Base>::Renegotiate(const FunctionCallbackInfo<Value>& args) {

ClearErrorOnReturn clear_error_on_return;

// XXX(sam) Return/throw an error, don't discard the SSL error reason.
bool yes = SSL_renegotiate(w->ssl_.get()) == 1;
args.GetReturnValue().Set(yes);
}
@@ -2134,7 +2135,7 @@ template <class Base>
void SSLWrap<Base>::NewSessionDone(const FunctionCallbackInfo<Value>& args) {
Base* w;
ASSIGN_OR_RETURN_UNWRAP(&w, args.Holder());
w->new_session_wait_ = false;
w->awaiting_new_session_ = false;
w->NewSessionDoneCb();
}

@@ -218,7 +218,7 @@ class SSLWrap {
kind_(kind),
next_sess_(nullptr),
session_callbacks_(false),
new_session_wait_(false),
awaiting_new_session_(false),
cert_cb_(nullptr),
cert_cb_arg_(nullptr),
cert_cb_running_(false) {
@@ -234,7 +234,7 @@ class SSLWrap {
inline void enable_session_callbacks() { session_callbacks_ = true; }
inline bool is_server() const { return kind_ == kServer; }
inline bool is_client() const { return kind_ == kClient; }
inline bool is_waiting_new_session() const { return new_session_wait_; }
inline bool is_awaiting_new_session() const { return awaiting_new_session_; }
inline bool is_waiting_cert_cb() const { return cert_cb_ != nullptr; }

protected:
@@ -325,7 +325,7 @@ class SSLWrap {
SSLSessionPointer next_sess_;
SSLPointer ssl_;
bool session_callbacks_;
bool new_session_wait_;
bool awaiting_new_session_;

// SSL_set_cert_cb
CertCb cert_cb_;
@@ -34,8 +34,8 @@ namespace node {
namespace crypto {

// This class represents buffers for OpenSSL I/O, implemented as a singly-linked
// list of chunks. It can be used both for writing data from Node to OpenSSL
// and back, but only one direction per instance.
// list of chunks. It can be used either for writing data from Node to OpenSSL,
// or for reading data back, but not both.
// The structure is only accessed, and owned by, the OpenSSL BIOPointer
// (a.k.a. std::unique_ptr<BIO>).
class NodeBIO : public MemoryRetainer {
@@ -80,11 +80,12 @@ class NodeBIO : public MemoryRetainer {
// Put `len` bytes from `data` into buffer
void Write(const char* data, size_t size);

// Return pointer to internal data and amount of
// contiguous data available for future writes
// Return pointer to contiguous block of reserved data and the size available
// for future writes. Call Commit() once the write is complete.
char* PeekWritable(size_t* size);

// Commit reserved data
// Specify how much data was written into the block returned by
// PeekWritable().
void Commit(size_t size);


@@ -30,6 +30,9 @@
namespace node {
namespace crypto {

// Parse the client hello so we can do async session resumption. OpenSSL's
// session resumption uses synchronous callbacks, see SSL_CTX_sess_set_get_cb
// and get_session_cb.
class ClientHelloParser {
public:
inline ClientHelloParser();
@@ -232,7 +232,7 @@ void LibuvStreamWrap::OnUvRead(ssize_t nread, const uv_buf_t* buf) {
type = uv_pipe_pending_type(reinterpret_cast<uv_pipe_t*>(stream()));
}

// We should not be getting this callback if someone as already called
// We should not be getting this callback if someone has already called
// uv_close() on the handle.
CHECK_EQ(persistent().IsEmpty(), false);

@@ -114,6 +114,11 @@ void TLSWrap::InitSSL() {
#endif // SSL_MODE_RELEASE_BUFFERS

SSL_set_app_data(ssl_.get(), this);
// Using InfoCallback isn't how we are supposed to check handshake progress:
// https://github.com/openssl/openssl/issues/7199#issuecomment-420915993
//
// Note on when this gets called on various openssl versions:
// https://github.com/openssl/openssl/issues/7199#issuecomment-420670544
SSL_set_info_callback(ssl_.get(), SSLInfoCallback);

if (is_server()) {
@@ -192,6 +197,9 @@ void TLSWrap::Start(const FunctionCallbackInfo<Value>& args) {

// Send ClientHello handshake
CHECK(wrap->is_client());
// Seems odd to read when when we want to send, but SSL_read() triggers a
// handshake if a session isn't established, and handshake will cause
// encrypted data to become available for output.
wrap->ClearOut();
wrap->EncOut();
}
@@ -246,7 +254,7 @@ void TLSWrap::EncOut() {
return;

// Wait for `newSession` callback to be invoked
if (is_waiting_new_session())
if (is_awaiting_new_session())
return;

// Split-off queue
@@ -256,7 +264,7 @@ void TLSWrap::EncOut() {
if (ssl_ == nullptr)
return;

// No data to write
// No encrypted output ready to write to the underlying stream.
if (BIO_pending(enc_out_) == 0) {
if (pending_cleartext_input_.empty())
InvokeQueued(0);
@@ -443,13 +451,13 @@ void TLSWrap::ClearOut() {
}


bool TLSWrap::ClearIn() {
void TLSWrap::ClearIn() {
// Ignore cycling data if ClientHello wasn't yet parsed
if (!hello_parser_.IsEnded())
return false;
return;

if (ssl_ == nullptr)
return false;
return;

std::vector<uv_buf_t> buffers;
buffers.swap(pending_cleartext_input_);
@@ -469,8 +477,9 @@ bool TLSWrap::ClearIn() {

// All written
if (i == buffers.size()) {
// We wrote all the buffers, so no writes failed (written < 0 on failure).
CHECK_GE(written, 0);
return true;
return;
}

// Error or partial write
@@ -482,6 +491,8 @@ bool TLSWrap::ClearIn() {
Local<Value> arg = GetSSLError(written, &err, &error_str);
if (!arg.IsEmpty()) {
write_callback_scheduled_ = true;
// XXX(sam) Should forward an error object with .code/.function/.etc, if
// possible.
InvokeQueued(UV_EPROTO, error_str.c_str());
} else {
// Push back the not-yet-written pending buffers into their queue.
@@ -492,7 +503,7 @@ bool TLSWrap::ClearIn() {
buffers.end());
}

return false;
return;
}


@@ -548,6 +559,7 @@ void TLSWrap::ClearError() {
}


// Called by StreamBase::Write() to request async write of clear text into SSL.
int TLSWrap::DoWrite(WriteWrap* w,
uv_buf_t* bufs,
size_t count,
@@ -561,18 +573,26 @@ int TLSWrap::DoWrite(WriteWrap* w,
}

bool empty = true;

// Empty writes should not go through encryption process
size_t i;
for (i = 0; i < count; i++)
for (i = 0; i < count; i++) {
if (bufs[i].len > 0) {
empty = false;
break;
}
}

// We want to trigger a Write() on the underlying stream to drive the stream
// system, but don't want to encrypt empty buffers into a TLS frame, so see
// if we can find something to Write().
// First, call ClearOut(). It does an SSL_read(), which might cause handshake
// or other internal messages to be encrypted. If it does, write them later
// with EncOut().
// If there is still no encrypted output, call Write(bufs) on the underlying
// stream. Since the bufs are empty, it won't actually write non-TLS data
// onto the socket, we just want the side-effects. After, make sure the
// WriteWrap was accepted by the stream, or that we call Done() on it.
if (empty) {
ClearOut();
// However, if there is any data that should be written to the socket,
// the callback should not be invoked immediately
if (BIO_pending(enc_out_) == 0) {
CHECK_NULL(current_empty_write_);
current_empty_write_ = w;
@@ -592,7 +612,7 @@ int TLSWrap::DoWrite(WriteWrap* w,
CHECK_NULL(current_write_);
current_write_ = w;

// Write queued data
// Write encrypted data to underlying stream and call Done().
if (empty) {
EncOut();
return 0;
@@ -611,17 +631,20 @@ int TLSWrap::DoWrite(WriteWrap* w,
if (i != count) {
int err;
Local<Value> arg = GetSSLError(written, &err, &error_);

// If we stopped writing because of an error, it's fatal, discard the data.
if (!arg.IsEmpty()) {
current_write_ = nullptr;
return UV_EPROTO;
}

// Otherwise, save unwritten data so it can be written later by ClearIn().
pending_cleartext_input_.insert(pending_cleartext_input_.end(),
&bufs[i],
&bufs[count]);
}

// Try writing data immediately
// Write any encrypted/handshake output that may be ready.
EncOut();

return 0;
@@ -653,17 +676,20 @@ void TLSWrap::OnStreamRead(ssize_t nread, const uv_buf_t& buf) {
return;
}

// Only client connections can receive data
if (ssl_ == nullptr) {
EmitRead(UV_EPROTO);
return;
}

// Commit read data
// Commit the amount of data actually read into the peeked/allocated buffer
// from the underlying stream.
crypto::NodeBIO* enc_in = crypto::NodeBIO::FromBIO(enc_in_);
enc_in->Commit(nread);

// Parse ClientHello first
// Parse ClientHello first, if we need to. It's only parsed if session event
// listeners are used on the server side. "ended" is the initial state, so
// can mean parsing was never started, or that parsing is finished. Either
// way, ended means we can give the buffered data to SSL.
if (!hello_parser_.IsEnded()) {
size_t avail = 0;
uint8_t* data = reinterpret_cast<uint8_t*>(enc_in->Peek(&avail));
@@ -72,7 +72,9 @@ class TLSWrap : public AsyncWrap,
uv_buf_t* bufs,
size_t count,
uv_stream_t* send_handle) override;
// Return error_ string or nullptr if it's empty.
const char* Error() const override;
// Reset error_ string to empty. Not related to "clear text".
void ClearError() override;

void NewSessionDoneCb();
@@ -105,11 +107,22 @@ class TLSWrap : public AsyncWrap,

static void SSLInfoCallback(const SSL* ssl_, int where, int ret);
void InitSSL();
void EncOut();
bool ClearIn();
void ClearOut();
// SSL has a "clear" text (unencrypted) side (to/from the node API) and
// encrypted ("enc") text side (to/from the underlying socket/stream).
// On each side data flows "in" or "out" of SSL context.
//
// EncIn() doesn't exist. Encrypted data is pushed from underlying stream into
// enc_in_ via the stream listener's OnStreamAlloc()/OnStreamRead() interface.
void EncOut(); // Write encrypted data from enc_out_ to underlying stream.
void ClearIn(); // SSL_write() clear data "in" to SSL.
void ClearOut(); // SSL_read() clear text "out" from SSL.

// Call Done() on outstanding WriteWrap request.
bool InvokeQueued(int status, const char* error_str = nullptr);

// Drive the SSL state machine by attempting to SSL_read() and SSL_write() to
// it. Transparent handshakes mean SSL_read() might trigger I/O on the
// underlying stream even if there is no clear text to read or write.
inline void Cycle() {
// Prevent recursion
if (++cycle_depth_ > 1)
@@ -118,6 +131,7 @@ class TLSWrap : public AsyncWrap,
for (; cycle_depth_ > 0; cycle_depth_--) {
ClearIn();
ClearOut();
// EncIn() doesn't exist, it happens via stream listener callbacks.
EncOut();
}
}
@@ -139,16 +153,18 @@ class TLSWrap : public AsyncWrap,
static void SetVerifyMode(const v8::FunctionCallbackInfo<v8::Value>& args);
static void EnableSessionCallbacks(
const v8::FunctionCallbackInfo<v8::Value>& args);
static void EnableCertCb(
const v8::FunctionCallbackInfo<v8::Value>& args);
static void EnableTrace(const v8::FunctionCallbackInfo<v8::Value>& args);
static void EnableCertCb(const v8::FunctionCallbackInfo<v8::Value>& args);
static void DestroySSL(const v8::FunctionCallbackInfo<v8::Value>& args);
static void GetServername(const v8::FunctionCallbackInfo<v8::Value>& args);
static void SetServername(const v8::FunctionCallbackInfo<v8::Value>& args);
static int SelectSNIContextCallback(SSL* s, int* ad, void* arg);

crypto::SecureContext* sc_;
BIO* enc_in_ = nullptr;
BIO* enc_out_ = nullptr;
// BIO buffers hold encrypted data.
BIO* enc_in_ = nullptr; // StreamListener fills this for SSL_read().
BIO* enc_out_ = nullptr; // SSL_write()/handshake fills this for EncOut().
// Waiting for ClearIn() to pass to SSL_write().
std::vector<uv_buf_t> pending_cleartext_input_;
size_t write_size_ = 0;
WriteWrap* current_write_ = nullptr;

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