- local object = { mechanism = "DIGEST-MD5", onAuth = onAuth, onSuccess = onSuccess, onFail = onFail,
- onWrite = onWrite }
-
- --TODO: something better than math.random would be nice, maybe OpenSSL's random number generator
- object.nonce = generate_uuid()
- log("debug", "SASL nonce: "..object.nonce)
- object.step = 1
- object.nonce_count = {}
- local challenge = base64.encode(serialize({ nonce = object.nonce,
- qop = "auth",
- charset = "utf-8",
- algorithm = "md5-sess"} ));
- object.onWrite(st.stanza("challenge", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}):text(challenge))
- object.feed = function(self, stanza)
- log("debug", "SASL step: "..self.step)
- if stanza.name ~= "response" and stanza.name ~= "auth" then self.onFail("invalid-stanza-tag") end
- if stanza.attr.xmlns ~= "urn:ietf:params:xml:ns:xmpp-sasl" then self.onFail("invalid-stanza-namespace") end
- if stanza.name == "auth" then return end
- self.step = self.step + 1
- if (self.step == 2) then
- local response = parse(base64.decode(stanza[1]))
- -- check for replay attack
- if response["nc"] then
- if self.nonce_count[response["nc"]] then self.onFail("not-authorized") end
- end
-
- -- check for username, it's REQUIRED by RFC 2831
- if not response["username"] then
- self.onFail("malformed-request")
- end
- self["username"] = response["username"]
-
- -- check for nonce, ...
- if not response["nonce"] then
- self.onFail("malformed-request")
- else
- -- check if it's the right nonce
- if response["nonce"] ~= tostring(self.nonce) then self.onFail("malformed-request") end
- end
-
- if not response["cnonce"] then self.onFail("malformed-request") end
- if not response["qop"] then response["qop"] = "auth" end
-
- if response["realm"] == nil then response["realm"] = "" end
-
- local domain = ""
- local protocol = ""
- if response["digest-uri"] then
- protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$")
- else
- error("No digest-uri")
- end
-
- -- compare response_value with own calculation
- --local A1 = usermanager.get_md5(response["username"], hostname)..":"..response["nonce"]..response["cnonce"]
-
- --FIXME actual username and password here :P
- local X = "tobias:"..response["realm"]..":tobias"
- local Y = md5.sum(X)
- local A1 = Y..":"..response["nonce"]..":"..response["cnonce"]--:authzid
- local A2 = "AUTHENTICATE:"..protocol.."/"..domain
-
- local HA1 = md5.sumhexa(A1)
- local HA2 = md5.sumhexa(A2)
-
- local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
- local response_value = md5.sumhexa(KD)
-
- log("debug", "response_value: "..response_value);
- log("debug", "response: "..response["response"]);
- if response_value == response["response"] then
- -- calculate rspauth
- A2 = ":"..protocol.."/"..domain
-
- HA1 = md5.sumhexa(A1)
- HA2 = md5.sumhexa(A2)
-
- KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
- local rspauth = md5.sumhexa(KD)
-
- self.onWrite(st.stanza("challenge", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}):text(base64.encode(serialize({rspauth = rspauth}))))
- else
- self.onWrite(st.stanza("response", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}))
- self.onFail()
- end
- elseif self.step == 3 then
- if stanza.name == "response" then
- self.onWrite(st.stanza("success", {xmlns = "urn:ietf:params:xml:ns:xmpp-sasl"}))
- self.onSuccess(self.username)
- else
- self.onFail("Third step isn't a response stanza.")
- end
- end
- end
+ local object = { mechanism = "DIGEST-MD5", realm = realm, credentials_handler = credentials_handler};
+
+ object.nonce = generate_uuid();
+ object.step = 0;
+ object.nonce_count = {};
+
+ function object.feed(self, message)
+ self.step = self.step + 1;
+ if (self.step == 1) then
+ local challenge = serialize({ nonce = object.nonce,
+ qop = "auth",
+ charset = "utf-8",
+ algorithm = "md5-sess",
+ realm = self.realm});
+ return "challenge", challenge;
+ elseif (self.step == 2) then
+ local response = parse(message);
+ -- check for replay attack
+ if response["nc"] then
+ if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end
+ end
+
+ -- check for username, it's REQUIRED by RFC 2831
+ if not response["username"] then
+ return "failure", "malformed-request";
+ end
+ self["username"] = response["username"];
+
+ -- check for nonce, ...
+ if not response["nonce"] then
+ return "failure", "malformed-request";
+ else
+ -- check if it's the right nonce
+ if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end
+ end
+
+ if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end
+ if not response["qop"] then response["qop"] = "auth" end
+
+ if response["realm"] == nil or response["realm"] == "" then
+ response["realm"] = "";
+ elseif response["realm"] ~= self.realm then
+ return "failure", "not-authorized", "Incorrect realm value";
+ end
+
+ local decoder;
+ if response["charset"] == nil then
+ decoder = utf8tolatin1ifpossible;
+ elseif response["charset"] ~= "utf-8" then
+ return "failure", "incorrect-encoding", "The client's response uses "..response["charset"].." for encoding with isn't supported by sasl.lua. Supported encodings are latin or utf-8.";
+ end
+
+ local domain = "";
+ local protocol = "";
+ if response["digest-uri"] then
+ protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$");
+ if protocol == nil or domain == nil then return "failure", "malformed-request" end
+ else
+ return "failure", "malformed-request", "Missing entry for digest-uri in SASL message."
+ end
+
+ --TODO maybe realm support
+ self.username = response["username"];
+ local password_encoding, Y = self.credentials_handler("DIGEST-MD5", response["username"], self.realm, response["realm"], decoder);
+ if Y == nil then return "failure", "not-authorized"
+ elseif Y == false then return "failure", "account-disabled" end
+ local A1 = "";
+ if response.authzid then
+ if response.authzid == self.username.."@"..self.realm then
+ -- COMPAT
+ log("warn", "Client is violating XMPP RFC. See section 6.1 of RFC 3920.");
+ A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid;
+ else
+ A1 = "?";
+ end
+ else
+ A1 = Y..":"..response["nonce"]..":"..response["cnonce"];
+ end
+ local A2 = "AUTHENTICATE:"..protocol.."/"..domain;
+
+ local HA1 = md5(A1, true);
+ local HA2 = md5(A2, true);
+
+ local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2;
+ local response_value = md5(KD, true);
+
+ if response_value == response["response"] then
+ -- calculate rspauth
+ A2 = ":"..protocol.."/"..domain;
+
+ HA1 = md5(A1, true);
+ HA2 = md5(A2, true);
+
+ KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2
+ local rspauth = md5(KD, true);
+ self.authenticated = true;
+ return "challenge", serialize({rspauth = rspauth});
+ else
+ return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated."
+ end
+ elseif self.step == 3 then
+ if self.authenticated ~= nil then return "success"
+ else return "failure", "malformed-request" end
+ end
+ end
+ return object;
+end
+
+-- Credentials handler: Can be nil. If specified, should take the mechanism as
+-- the only argument, and return true for OK, or false for not-OK (TODO)
+local function new_anonymous(realm, credentials_handler)
+ local object = { mechanism = "ANONYMOUS", realm = realm, credentials_handler = credentials_handler}
+ function object.feed(self, message)
+ return "success"
+ end
+ object["username"] = generate_uuid()