Update mbedtls to 2.5.1 (#3964)

* Renaming changes:
  * macro prefix "POLARSSL" -> "MBEDTLS"
  * functions now prefixed with "mbedtls_"
  * rename PolarSSL++ -> mbedTLS++
  * rename polarssl submodule

* Use mbedtls' AES-CFB8 implementation.

* Add cSslConfig to wrap mbedtls_ssl_config

* Update cTCPLink and cBlockingSslClientSocket to use cSslConfig

* Use cSslConfig in cHTTPServer

* Use cSslConfig for cMojangAPI::SecureRequest

* CI Fixes

* Set -fomit-frame-pointer on the right target

src/mbedTLS++/SslContext.cpp

@@ -0,0 +1,157 @@
+
+// SslContext.cpp
+
+// Implements the cSslContext class that holds everything a single SSL context needs to function
+
+#include "Globals.h"
+#include "mbedTLS++/SslContext.h"
+#include "mbedTLS++/SslConfig.h"
+
+
+
+
+
+cSslContext::cSslContext(void) :
+	m_IsValid(false),
+	m_HasHandshaken(false)
+{
+	mbedtls_ssl_init(&m_Ssl);
+}
+
+
+
+
+
+cSslContext::~cSslContext()
+{
+	mbedtls_ssl_free(&m_Ssl);
+}
+
+
+
+
+
+int cSslContext::Initialize(std::shared_ptr<const cSslConfig> a_Config)
+{
+	// Check double-initialization:
+	if (m_IsValid)
+	{
+		LOGWARNING("SSL: Double initialization is not supported.");
+		return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;  // There is no return value well-suited for this, reuse this one.
+	}
+
+	// Check the Config:
+	m_Config = a_Config;
+	if (m_Config == nullptr)
+	{
+		ASSERT(!"Config must not be nullptr");
+		return MBEDTLS_ERR_SSL_BAD_INPUT_DATA;
+	}
+
+	// Apply the configuration to the ssl context
+	int res = mbedtls_ssl_setup(&m_Ssl, m_Config->GetInternal());
+	if (res != 0)
+	{
+		return res;
+	}
+
+	// Set the io callbacks
+	mbedtls_ssl_set_bio(&m_Ssl, this, SendEncrypted, ReceiveEncrypted, nullptr);
+
+	m_IsValid = true;
+	return 0;
+}
+
+
+
+
+
+int cSslContext::Initialize(bool a_IsClient)
+{
+	if (a_IsClient)
+	{
+		return Initialize(cSslConfig::GetDefaultClientConfig());
+	}
+	else
+	{
+		return Initialize(cSslConfig::GetDefaultServerConfig());
+	}
+}
+
+
+
+
+
+void cSslContext::SetExpectedPeerName(const AString & a_ExpectedPeerName)
+{
+	ASSERT(m_IsValid);  // Call Initialize() first
+	mbedtls_ssl_set_hostname(&m_Ssl, a_ExpectedPeerName.c_str());
+}
+
+
+
+
+
+int cSslContext::WritePlain(const void * a_Data, size_t a_NumBytes)
+{
+	ASSERT(m_IsValid);  // Need to call Initialize() first
+	if (!m_HasHandshaken)
+	{
+		int res = Handshake();
+		if (res != 0)
+		{
+			return res;
+		}
+	}
+
+	return mbedtls_ssl_write(&m_Ssl, reinterpret_cast<const unsigned char *>(a_Data), a_NumBytes);
+}
+
+
+
+
+
+int cSslContext::ReadPlain(void * a_Data, size_t a_MaxBytes)
+{
+	ASSERT(m_IsValid);  // Need to call Initialize() first
+	if (!m_HasHandshaken)
+	{
+		int res = Handshake();
+		if (res != 0)
+		{
+			return res;
+		}
+	}
+
+	return mbedtls_ssl_read(&m_Ssl, reinterpret_cast<unsigned char *>(a_Data), a_MaxBytes);
+}
+
+
+
+
+
+int cSslContext::Handshake(void)
+{
+	ASSERT(m_IsValid);  // Need to call Initialize() first
+	ASSERT(!m_HasHandshaken);  // Must not call twice
+
+	int res = mbedtls_ssl_handshake(&m_Ssl);
+	if (res == 0)
+	{
+		m_HasHandshaken = true;
+	}
+	return res;
+}
+
+
+
+
+
+int cSslContext::NotifyClose(void)
+{
+	return mbedtls_ssl_close_notify(&m_Ssl);
+}
+
+
+
+