1 files changed, 143 insertions, 0 deletions
diff --git a/Swiften/SASL/SCRAMSHA1ClientAuthenticator.cpp b/Swiften/SASL/SCRAMSHA1ClientAuthenticator.cpp
new file mode 100644
index 0000000..5dc924e
--- /dev/null
+++ b/Swiften/SASL/SCRAMSHA1ClientAuthenticator.cpp
@@ -0,0 +1,143 @@
+#include "Swiften/SASL/SCRAMSHA1ClientAuthenticator.h"
+
+#include <cassert>
+#include <map>
+#include <boost/lexical_cast.hpp>
+
+#include "Swiften/StringCodecs/SHA1.h"
+#include "Swiften/StringCodecs/Base64.h"
+#include "Swiften/StringCodecs/HMACSHA1.h"
+#include "Swiften/StringCodecs/PBKDF2.h"
+#include "Swiften/StringPrep/StringPrep.h"
+
+namespace Swift {
+
+static String escape(const String& s) {
+	String result;
+	for (size_t i = 0; i < s.getUTF8Size(); ++i) {
+		if (s[i] == ',') {
+			result += "=2C";
+		}
+		else if (s[i] == '=') {
+			result += "=3D";
+		}
+		else {
+			result += s[i];
+		}
+	}
+	return result;
+}
+
+
+SCRAMSHA1ClientAuthenticator::SCRAMSHA1ClientAuthenticator(const String& nonce) : ClientAuthenticator("SCRAM-SHA-1"), step(Initial), clientnonce(nonce) {
+}
+
+ByteArray SCRAMSHA1ClientAuthenticator::getResponse() const {
+	if (step == Initial) {
+		return getGS2Header() + getInitialBareClientMessage();
+	}
+	else if (step == Proof) {
+		ByteArray clientKey = HMACSHA1::getResult(saltedPassword, "Client Key");
+		ByteArray storedKey = SHA1::getHash(clientKey);
+		ByteArray clientSignature = HMACSHA1::getResult(storedKey, authMessage);
+		ByteArray clientProof = clientKey;
+		for (unsigned int i = 0; i < clientProof.getSize(); ++i) {
+			clientProof[i] ^= clientSignature[i];
+		}
+		ByteArray result = ByteArray("c=") + Base64::encode(getGS2Header()) + ",r=" + clientnonce + serverNonce + ",p=" + Base64::encode(clientProof);
+		return result;
+	}
+	else {
+		return ByteArray();
+	}
+}
+
+bool SCRAMSHA1ClientAuthenticator::setChallenge(const ByteArray& challenge) {
+	if (step == Initial) {
+		initialServerMessage = challenge;
+
+		std::map<char, String> keys = parseMap(String(initialServerMessage.getData(), initialServerMessage.getSize()));
+
+		// Extract the salt
+		ByteArray salt = Base64::decode(keys['s']);
+
+		// Extract the server nonce
+		String clientServerNonce = keys['r'];
+		if (clientServerNonce.getUTF8Size() <= clientnonce.getUTF8Size()) {
+			return false;
+		}
+		String receivedClientNonce = clientServerNonce.getSubstring(0, clientnonce.getUTF8Size());
+		if (receivedClientNonce != clientnonce) {
+			return false;
+		}
+		serverNonce = clientServerNonce.getSubstring(clientnonce.getUTF8Size(), clientServerNonce.npos());
+
+		// Extract the number of iterations
+		int iterations = 0;
+		try {
+			iterations = boost::lexical_cast<int>(keys['i'].getUTF8String());
+		}
+		catch (const boost::bad_lexical_cast&) {
+			return false;
+		}
+		if (iterations <= 0) {
+			return false;
+		}
+
+		// Compute all the values needed for the server signature
+		saltedPassword = PBKDF2::encode(StringPrep::getPrepared(getPassword(), StringPrep::SASLPrep), salt, iterations);
+		authMessage = getInitialBareClientMessage() + "," + initialServerMessage + "," + "c=" + Base64::encode(getGS2Header()) + ",r=" + clientnonce + serverNonce;
+		ByteArray serverKey = HMACSHA1::getResult(saltedPassword, "Server Key");
+		serverSignature = HMACSHA1::getResult(serverKey, authMessage);
+
+		step = Proof;
+		return true;
+	}
+	else if (step == Proof) {
+		ByteArray result = ByteArray("v=") + ByteArray(Base64::encode(serverSignature));
+		step = Final;
+		return challenge == result;
+	}
+	else {
+		return true;
+	}
+}
+
+std::map<char, String> SCRAMSHA1ClientAuthenticator::parseMap(const String& s) {
+	std::map<char, String> result;
+	if (s.getUTF8Size() > 0) {
+		char key;
+		String value;
+		size_t i = 0;
+		bool expectKey = true;
+		while (i < s.getUTF8Size()) {
+			if (expectKey) {
+				key = s[i];
+				expectKey = false;
+				i++;
+			}
+			else if (s[i] == ',') {
+				result[key] = value;
+				value = "";
+				expectKey = true;
+			}
+			else {
+				value += s[i];
+			}
+			i++;
+		}
+		result[key] = value;
+	}
+	return result;
+}
+
+ByteArray SCRAMSHA1ClientAuthenticator::getInitialBareClientMessage() const {
+	String authenticationID = StringPrep::getPrepared(getAuthenticationID(), StringPrep::SASLPrep);
+	return ByteArray(String("n=" + escape(authenticationID) + ",r=" + clientnonce));
+}
+
+ByteArray SCRAMSHA1ClientAuthenticator::getGS2Header() const {
+	return ByteArray("n,") + (getAuthorizationID().isEmpty() ? "" : "a=" + escape(getAuthorizationID())) + ",";
+}
+
+}