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listener-filter: refactor tls_inspector so its logic could be shared with custom filters #4331

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listener-filter: refactor tls_inspector so its logic could be shared with custom filters #4331

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6608883
Refactor tls_inspector so its logic could be shared with custom filters
ronensc Sep 4, 2018
55db8f2
Change Config's Ctor params order and set default value to stat_prefix
ronensc Sep 4, 2018
a102c48
Merge branch 'master' of github.com:envoyproxy/envoy into tls-inspect…
vadimeisenbergibm Sep 5, 2018
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94 changes: 64 additions & 30 deletions source/extensions/filters/listener/tls_inspector/tls_inspector.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -24,8 +24,8 @@ namespace Extensions {
namespace ListenerFilters {
namespace TlsInspector {

Config::Config(Stats::Scope& scope, uint32_t max_client_hello_size)
: stats_{ALL_TLS_INSPECTOR_STATS(POOL_COUNTER_PREFIX(scope, "tls_inspector."))},
Config::Config(Stats::Scope& scope, uint32_t max_client_hello_size, const std::string& stat_prefix)
: stats_{TLS_STATS(POOL_COUNTER_PREFIX(scope, stat_prefix))},
ssl_ctx_(SSL_CTX_new(TLS_with_buffers_method())),
max_client_hello_size_(max_client_hello_size) {

Expand All @@ -42,14 +42,14 @@ Config::Config(Stats::Scope& scope, uint32_t max_client_hello_size)
size_t len;
if (SSL_early_callback_ctx_extension_get(
client_hello, TLSEXT_TYPE_application_layer_protocol_negotiation, &data, &len)) {
Filter* filter = static_cast<Filter*>(SSL_get_app_data(client_hello->ssl));
TlsFilterBase* filter = static_cast<TlsFilterBase*>(SSL_get_app_data(client_hello->ssl));
filter->onALPN(data, len);
}
return ssl_select_cert_success;
});
SSL_CTX_set_tlsext_servername_callback(
ssl_ctx_.get(), [](SSL* ssl, int* out_alert, void*) -> int {
Filter* filter = static_cast<Filter*>(SSL_get_app_data(ssl));
TlsFilterBase* filter = static_cast<TlsFilterBase*>(SSL_get_app_data(ssl));
filter->onServername(SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name));

// Return an error to stop the handshake; we have what we wanted already.
Expand All @@ -63,10 +63,16 @@ bssl::UniquePtr<SSL> Config::newSsl() { return bssl::UniquePtr<SSL>{SSL_new(ssl_
thread_local uint8_t Filter::buf_[Config::TLS_MAX_CLIENT_HELLO];

Filter::Filter(const ConfigSharedPtr config) : config_(config), ssl_(config_->newSsl()) {
RELEASE_ASSERT(sizeof(buf_) >= config_->maxClientHelloSize(), "");
initializeSsl(config->maxClientHelloSize(), sizeof(buf_), ssl_,
static_cast<TlsFilterBase*>(this));
}

void Filter::initializeSsl(uint32_t maxClientHelloSize, size_t bufSize,
const bssl::UniquePtr<SSL>& ssl, void* appData) {
RELEASE_ASSERT(bufSize >= maxClientHelloSize, "");

SSL_set_app_data(ssl_.get(), this);
SSL_set_accept_state(ssl_.get());
SSL_set_app_data(ssl.get(), appData);
SSL_set_accept_state(ssl.get());
}

Network::FilterStatus Filter::onAccept(Network::ListenerFilterCallbacks& cb) {
Expand Down Expand Up @@ -100,6 +106,16 @@ Network::FilterStatus Filter::onAccept(Network::ListenerFilterCallbacks& cb) {
}

void Filter::onALPN(const unsigned char* data, unsigned int len) {
doOnALPN(data, len,
[&](std::vector<absl::string_view> protocols) {
cb_->socket().setRequestedApplicationProtocols(protocols);
},
alpn_found_);
}

void Filter::doOnALPN(const unsigned char* data, unsigned int len,
std::function<void(std::vector<absl::string_view> protocols)> onAlpnCb,
bool& alpn_found) {
CBS wire, list;
CBS_init(&wire, reinterpret_cast<const uint8_t*>(data), static_cast<size_t>(len));
if (!CBS_get_u16_length_prefixed(&wire, &list) || CBS_len(&wire) != 0 || CBS_len(&list) < 2) {
Expand All @@ -115,19 +131,28 @@ void Filter::onALPN(const unsigned char* data, unsigned int len) {
}
protocols.emplace_back(reinterpret_cast<const char*>(CBS_data(&name)), CBS_len(&name));
}
cb_->socket().setRequestedApplicationProtocols(protocols);
alpn_found_ = true;
onAlpnCb(protocols);
alpn_found = true;
}

void Filter::onServername(absl::string_view servername) {
ENVOY_LOG(debug, "tls:onServerName(), requestedServerName: {}", servername);
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Should we keep this similar debug log in tcp_proxy

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I think it can be useful for debug to track that the SNI in both filters

doOnServername(
servername, config_->stats(),
[&](absl::string_view name) -> void { cb_->socket().setRequestedServerName(name); },
clienthello_success_);
}

void Filter::onServername(absl::string_view name) {
void Filter::doOnServername(absl::string_view name, const TlsStats& stats,
std::function<void(absl::string_view name)> onServernameCb,
bool& clienthello_success) {
if (!name.empty()) {
config_->stats().sni_found_.inc();
cb_->socket().setRequestedServerName(name);
ENVOY_LOG(debug, "tls:onServerName(), requestedServerName: {}", name);
stats.sni_found_.inc();
onServernameCb(name);
} else {
config_->stats().sni_not_found_.inc();
stats.sni_not_found_.inc();
}
clienthello_success_ = true;
clienthello_success = true;
}

void Filter::onRead() {
Expand Down Expand Up @@ -162,7 +187,13 @@ void Filter::onRead() {
const uint8_t* data = buf_ + read_;
const size_t len = result.rc_ - read_;
read_ = result.rc_;
parseClientHello(data, len);
parseClientHello(data, len, ssl_, read_, config_->maxClientHelloSize(), config_->stats(),
[&](bool success) -> void { done(success); }, alpn_found_,
clienthello_success_,
[&]() -> void {
cb_->socket().setDetectedTransportProtocol(
TransportSockets::TransportSocketNames::get().Tls);
});
}
}

Expand All @@ -179,41 +210,44 @@ void Filter::done(bool success) {
cb_->continueFilterChain(success);
}

void Filter::parseClientHello(const void* data, size_t len) {
// Ownership is passed to ssl_ in SSL_set_bio()
void Filter::parseClientHello(const void* data, size_t len, bssl::UniquePtr<SSL>& ssl,
uint64_t read, uint32_t maxClientHelloSize, const TlsStats& stats,
std::function<void(bool)> done, bool& alpn_found,
bool& clienthello_success, std::function<void()> onSuccess) {
// Ownership is passed to ssl in SSL_set_bio()
bssl::UniquePtr<BIO> bio(BIO_new_mem_buf(data, len));

// Make the mem-BIO return that there is more data
// available beyond it's end
BIO_set_mem_eof_return(bio.get(), -1);

SSL_set_bio(ssl_.get(), bio.get(), bio.get());
SSL_set_bio(ssl.get(), bio.get(), bio.get());
bio.release();

int ret = SSL_do_handshake(ssl_.get());
int ret = SSL_do_handshake(ssl.get());

// This should never succeed because an error is always returned from the SNI callback.
ASSERT(ret <= 0);
switch (SSL_get_error(ssl_.get(), ret)) {
switch (SSL_get_error(ssl.get(), ret)) {
case SSL_ERROR_WANT_READ:
if (read_ == config_->maxClientHelloSize()) {
if (read == maxClientHelloSize) {
// We've hit the specified size limit. This is an unreasonably large ClientHello;
// indicate failure.
config_->stats().client_hello_too_large_.inc();
stats.client_hello_too_large_.inc();
done(false);
}
break;
case SSL_ERROR_SSL:
if (clienthello_success_) {
config_->stats().tls_found_.inc();
if (alpn_found_) {
config_->stats().alpn_found_.inc();
if (clienthello_success) {
stats.tls_found_.inc();
if (alpn_found) {
stats.alpn_found_.inc();
} else {
config_->stats().alpn_not_found_.inc();
stats.alpn_not_found_.inc();
}
cb_->socket().setDetectedTransportProtocol(TransportSockets::TransportSocketNames::get().Tls);
onSuccess();
} else {
config_->stats().tls_not_found_.inc();
stats.tls_not_found_.inc();
}
done(true);
break;
Expand Down
52 changes: 38 additions & 14 deletions source/extensions/filters/listener/tls_inspector/tls_inspector.h
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,7 @@ namespace TlsInspector {
/**
* All stats for the TLS inspector. @see stats_macros.h
*/
#define ALL_TLS_INSPECTOR_STATS(COUNTER) \
#define TLS_STATS(COUNTER) \
COUNTER(connection_closed) \
COUNTER(client_hello_too_large) \
COUNTER(read_error) \
Expand All @@ -32,50 +32,77 @@ namespace TlsInspector {
COUNTER(sni_not_found)

/**
* Definition of all stats for the TLS inspector. @see stats_macros.h
* Definition of stats for the TLS. @see stats_macros.h
*/
struct TlsInspectorStats {
ALL_TLS_INSPECTOR_STATS(GENERATE_COUNTER_STRUCT)
struct TlsStats {
TLS_STATS(GENERATE_COUNTER_STRUCT)
};

/**
* Global configuration for TLS inspector.
*/
class Config {
public:
Config(Stats::Scope& scope, uint32_t max_client_hello_size = TLS_MAX_CLIENT_HELLO);
Config(Stats::Scope& scope, uint32_t max_client_hello_size = TLS_MAX_CLIENT_HELLO,
const std::string& stat_prefix = "tls_inspector.");

const TlsInspectorStats& stats() const { return stats_; }
const TlsStats& stats() const { return stats_; }
bssl::UniquePtr<SSL> newSsl();
uint32_t maxClientHelloSize() const { return max_client_hello_size_; }

static constexpr size_t TLS_MAX_CLIENT_HELLO = 64 * 1024;

private:
TlsInspectorStats stats_;
TlsStats stats_;
bssl::UniquePtr<SSL_CTX> ssl_ctx_;
const uint32_t max_client_hello_size_;
};

typedef std::shared_ptr<Config> ConfigSharedPtr;

class TlsFilterBase {
public:
virtual ~TlsFilterBase() {}

private:
virtual void onALPN(const unsigned char* data, unsigned int len) PURE;
virtual void onServername(absl::string_view name) PURE;

// Allows callbacks on the SSL_CTX to set fields in this class.
friend class Config;
};

/**
* TLS inspector listener filter.
*/
class Filter : public Network::ListenerFilter, Logger::Loggable<Logger::Id::filter> {
class Filter : public Network::ListenerFilter,
public TlsFilterBase,
Logger::Loggable<Logger::Id::filter> {
public:
Filter(const ConfigSharedPtr config);

// Network::ListenerFilter
Network::FilterStatus onAccept(Network::ListenerFilterCallbacks& cb) override;
static void initializeSsl(uint32_t maxClientHelloSize, size_t bufSize,
const bssl::UniquePtr<SSL>& ssl, void* appData);
static void parseClientHello(const void* data, size_t len, bssl::UniquePtr<SSL>& ssl,
uint64_t read, uint32_t maxClientHelloSize, const TlsStats& stats,
std::function<void(bool)> done, bool& alpn_found,
bool& clienthello_success, std::function<void()> onSuccess);
static void doOnServername(absl::string_view name, const TlsStats& stats,
std::function<void(absl::string_view name)> onServernameCb,
bool& clienthello_success_);
static void doOnALPN(const unsigned char* data, unsigned int len,
std::function<void(std::vector<absl::string_view> protocols)> onAlpnCb,
bool& alpn_found);

private:
void parseClientHello(const void* data, size_t len);
void onRead();
void onTimeout();
void done(bool success);
void onALPN(const unsigned char* data, unsigned int len);
void onServername(absl::string_view name);
// Extensions::ListenerFilters::TlsInspector::TlsFilterBase
void onALPN(const unsigned char* data, unsigned int len) override;
void onServername(absl::string_view name) override;

ConfigSharedPtr config_;
Network::ListenerFilterCallbacks* cb_;
Expand All @@ -88,9 +115,6 @@ class Filter : public Network::ListenerFilter, Logger::Loggable<Logger::Id::filt
bool clienthello_success_{false};

static thread_local uint8_t buf_[Config::TLS_MAX_CLIENT_HELLO];

// Allows callbacks on the SSL_CTX to set fields in this class.
friend class Config;
};

} // namespace TlsInspector
Expand Down