seperated session from the srp flow - login tests pass, signup fail

3 files changed, 170 insertions, 300 deletions

diff --git a/lib/plainXHR.js b/lib/plainXHR.js
index 67d8137..95ceeac 100644
--- a/lib/plainXHR.js
+++ b/lib/plainXHR.js
@@ -1,20 +1,9 @@
-plainXHR = function() {
-
-  function getUrl()
-  {
-    return "";
-  }
-
-  function paths(path)
-  {
-    return path
-  }
+SRP.prototype.Remote = function() {
 
   // Perform ajax requests at the specified path, with the specified parameters
   // Calling back the specified function.
-  function ajaxRequest(relative_path, params, callback)
+  function ajaxRequest(url, params, callback)
   {
-    var full_url = this.geturl() + this.paths(relative_path);
     if( window.XMLHttpRequest)
       xhr = new XMLHttpRequest();
     else if (window.ActiveXObject){
@@ -33,7 +22,7 @@ plainXHR = function() {
           callback(parseResponse());
         }
       };
-      xhr.open("POST", full_url, true);
+      xhr.open("POST", url, true);
       xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
       xhr.setRequestHeader("Content-length", params.length);
       xhr.send(params);
@@ -90,35 +79,20 @@ plainXHR = function() {
     return response;
   };
 
-  function register(session, callback)
+  this.register = function(session, callback)
   {
-    this.ajaxRequest("register/salt/", "I="+session.getI(), callback);
-  }
-
-  function sendVerifier(session, callback) {
-    this.ajaxRequest("register/user/", "v="+session.getV().toString(16), callback);
-  }
-
-  function handshake(I, Astr, callback) {
-    this.ajaxRequest("handshake/", "I="+I+"&A="+Astr, callback);
+    ajaxRequest("register/salt/", "I="+session.getI(), callback);
   }
 
-  function authenticate(M, callback) {
-    this.ajaxRequest("authenticate/", "M="+M, callback);
+  this.sendVerifier = function(session, callback) {
+    ajaxRequest("register/user/", "v="+session.getV().toString(16), callback);
   }
 
-  function upgrade(M, callback) {
-    this.ajaxRequest("upgrade/authenticate/", "M="+M, callback);
+  this.handshake = function(session, callback) {
+    ajaxRequest("handshake/", "I="+session.getI()+"&A="+session.getAstr(), callback);
   }
 
-  return {
-    geturl: getUrl,
-    paths: paths,
-    ajaxRequest: ajaxRequest,
-    register: register,
-    register_send_verifier: sendVerifier,
-    handshake: handshake,
-    authenticate: authenticate,
-    upgrade: upgrade
+  this.authenticate = function(session, callback) {
+    ajaxRequest("authenticate/", "M="+session.getM(), callback);
   }
 }
diff --git a/lib/srp.js b/lib/srp.js
index 8cb0c03..b54d6b7 100644
--- a/lib/srp.js
+++ b/lib/srp.js
@@ -1,257 +1,45 @@
-function SRP(remote)
+function SRP(remote, session)
 {
-  // Variables session will be used in the SRP protocol
-  var Nstr = "115b8b692e0e045692cf280b436735c77a5a9e8a9e7ed56c965f87db5b2a2ece3";
-  var N = new BigInteger(Nstr, 16);
-  var g = new BigInteger("2");
-  var k = new BigInteger("c46d46600d87fef149bd79b81119842f3c20241fda67d06ef412d8f6d9479c58", 16);
-  var rng = new SecureRandom();
-  var a = new BigInteger(32, rng);
-  var A = g.modPow(a, N);
-  while(A.mod(N) == 0)
-  {
-    a = new BigInteger(32, rng);
-    A = g.modPow(a, N);
-  }
-  var Astr = A.toString(16);
-  var S = null;
-  var K = null;
-  var M = null;
-  var M2 = null;
-  var session = this;
-  var authenticated = false;
-  var I = document.getElementById("srp_username").value;
-  var p = document.getElementById("srp_password").value;
-  var V;
-  var salt;
-  remote = remote || plainXHR();
-
-  // *** Accessor methods ***
-
-  // allows setting the random number A for testing
-
-  this.calculateAndSetA = function(_a)
-  {
-    a = new BigInteger(_a, 16);
-    A = g.modPow(a, N);
-    Astr = A.toString(16);
-    return Astr;
-  };
-
-  // Returns the user's identity
-  this.getI = function()
-  {
-    return I;
-  };
-
-  // some 16 byte random number
-  this.getSalt = function() {
-    salt = salt || new BigInteger(64, rng).toString(16);
-    return salt
-  }
-
-  // Returns the BigInteger, g
-  this.getg = function()
-  {
-    return g;
-  };
-
-  // Returns the BigInteger, N
-  this.getN = function()
-  {
-    return N;
-  };
-
-  // Calculates the X value and return it as a BigInteger
-  this.calcX = function(s)
-  {
-    return new BigInteger(SHA256(s + SHA256(I + ":" + p)), 16);
-  };
-
-  this.getV = function(salt)
-  {
-    V = V || this.getg().modPow(this.calcX(salt), this.getN());
-    return V;
-  }
-
-  // Check whether or not a variable is defined
-  function isdefined ( variable)
-  {
-    return (typeof(window[variable]) != "undefined");
-  };    
-  
-  // *** Actions ***
+  var srp = this;
+  session = session || new this.Session();
+  remote = remote || new this.Remote();
 
   // Start the login process by identifying the user
   this.identify = function()
   {
-    this.remote.handshake(I, Astr, receive_salts);
+    remote.handshake(session, receive_salts);
   };
 
   // Receive login salts from the server, start calculations
   function receive_salts(response)
   {
-    if(response.error) {
-      session.error_message(response.error);
-  }
-  // B = 0 will make the algorithm always succeed - refuse such a server
-  // answer
-    else if(response.B == 0) {
-      session.error_message("Server send random number 0 - this is not allowed");
-    }
-    // If there is no algorithm specified, calculate M given s, B, and P
-    else if(!response.a)
-    {
-      calculations(response.s, response.B, p);
-      remote.authenticate(M, confirm_authentication)
+    // B = 0 will make the algorithm always succeed
+    // -> refuse such a server answer
+    if(response.B == 0) {
+      srp.error("Server send random number 0 - this is not allowed");
+    } else {
+      session.calculations(response.s, response.B);
+      remote.authenticate(session, confirm_authentication)
     }
-    // If there is an algorithm specified, start the login process
-    else {
-      upgrade(response.s, response.B, response.a, response.d);
-    } 
-  };
-  
-  // Calculate S, M, and M2
-  // This is the client side of the SRP specification
-  function calculations(s, ephemeral, pass)
-  {    
-    //S -> C: s | B
-    var B = new BigInteger(ephemeral, 16); 
-    var Bstr = ephemeral;
-    // u = H(A,B)
-    var u = new BigInteger(SHA256(Astr + Bstr), 16); 
-    // x = H(s, H(I:p))
-    var x = new BigInteger(SHA256(s + SHA256(I + ":" + pass)), 16);
-    //S = (B - kg^x) ^ (a + ux)
-    var kgx = k.multiply(g.modPow(x, N));  
-    var aux = a.add(u.multiply(x)); 
-    S = B.subtract(kgx).modPow(aux, N); 
-    // M = H(H(N) xor H(g), H(I), s, A, B, K)
-    var Mstr = A.toString(16) + B.toString(16) + S.toString(16); 
-    M = SHA256(Mstr);
-    M2 = SHA256(A.toString(16) + M + S.toString(16)); 
-    //M2 = H(A, M, K)
   };
 
   // Receive M2 from the server and verify it
+  // If an error occurs, raise it as an alert.
   function confirm_authentication(response)
   {
-    if(response.M)
-    {
-      if(response.M == M2)
-      {
-        authenticated = true;
-        session.success();
-      }
-      else
-        session.error_message("Server key does not match");
-    }
-    else if (response.error)
-      session.error_message(response.error);
-  };
-
-  // *** Upgrades ***
-
-  // Start the process to upgrade the user's account
-  function upgrade(s,ephemeral,algo,dsalt)
-  {
-    // First we need to import the hash functions
-    import_hashes();
-
-    // Once the hash functions are imported, do the calculations using the hashpass as the password
-    function do_upgrade()
-    {
-      // If sha1 and md5 are still undefined, sleep again
-      if(!isdefined("SHA1") || !isdefined("MD5"))
-      {
-        window.setTimeout(do_upgrade, 10);
-        return;
-      }
-      if(algo == "sha1")
-        hashfun = SHA1;
-      else if(algo == "md5")
-        hashfun = MD5;
-      //alert(hashfun(dsalt+p));
-      calculations(s, ephemeral, hashfun(dsalt+p));
-      remote.upgrade(M, session.confirm_upgrade)
-    };
-    window.setTimeout(do_upgrade,10);
-  };
-
-  // Encrypt plaintext using slowAES
-  function encrypt(plaintext)
-  {
-    var key = cryptoHelpers.toNumbers(session.key());
-    var byteMessage = cryptoHelpers.convertStringToByteArray(plaintext);
-    var iv = new Array(16);
-    rng.nextBytes(iv);
-    var paddedByteMessage = slowAES.getPaddedBlock(byteMessage, 0, byteMessage.length, slowAES.modeOfOperation.CFB);
-    var ciphertext = slowAES.encrypt(paddedByteMessage, slowAES.modeOfOperation.CFB, key, key.length, iv).cipher;
-    var retstring = cryptoHelpers.base64.encode(iv.concat(ciphertext));
-    while(retstring.indexOf("+",0) > -1)
-      retstring = retstring.replace("+", "_");
-    return retstring;
-  };
-
-  // Receive the server's M, confirming session the server has HASH(p)
-  // Next, send P in plaintext (this is the **only** time it should ever be sent plain text)
-  function confirm_upgrade(response)
-  {
-    if(response.M)
-    {
-      if(response.M == M2)
-      {
-        K = SHA256(S.toString(16));
-        var auth_url = session.geturl() + session.paths("upgrade/verifier/");
-        session.ajaxRequest(auth_url, "p="+encrypt(p)+"&l="+p.length, confirm_verifier);
-      }
-      else
-        session.error_message("Server key does not match");
-    }
-    else if (response.error)
-    {
-      session.error_message(response.error);
-    }
-  };
-
-  // After sending the password, check session the response is OK, then reidentify
-  function confirm_verifier(response)
-  {
-    K = null;
-    if(response.ok)
-      session.identify();
+    if (session.validate(response.M))
+      srp.success();
     else
-      session.error_message("Verifier could not be confirmed");
+      alertErrorMessage("Server key does not match");
   };
 
-  // This loads javascript libraries. Fname is the path to the library to be imported
-  function import_file(fname)
+  // Minimal error handling - set remote.onError to sth better to overwrite.
+  this.error = function(text)
   {
-    var scriptElt = document.createElement('script');
-    scriptElt.type = 'text/javascript';
-    scriptElt.src = fname;
-    document.getElementsByTagName('head')[0].appendChild(scriptElt);
+    alert(text);
   };
-  // If we need SHA1 or MD5, we need to load the javascript files
-  function import_hashes()
-  {
-    // First check session the functions aren't already loaded
-    if(isdefined("SHA1") && isdefined("MD5")) return;
-    // Get the directory session this javascript file was loaded from
-    var arr=session.srpPath.split("/");
-    var path = arr.slice(0, arr.length-1).join("/");
-    // If this file is called srp.min.js, we will load the packed hash file
-    if(arr[arr.length-1] == "srp.min.js")
-      import_file(path+"/crypto.min.js");
-    // Otherwise, this file is presumably srp.js, and we will load individual hash files
-    else
-    {
-      import_file(path+"/MD5.js");
-      import_file(path+"/SHA1.js");
-      import_file(path+"/cryptoHelpers.js");
-      import_file(path+"/aes.js");
-    }        
-  }
+  remote.onError = remote.onError || this.error;
+  session.onError = session.onError || this.error;
 
   // This function is called when authentication is successful.
   // Developers can set this to other functions in specific implementations
@@ -267,35 +55,5 @@ function SRP(remote)
       alert("Login successful.");
     }
   };
-  // If someone wants to use the session key for encrypting traffic, they can
-  // access the key with this function.
-  this.key = function()
-  {
-    if(K == null)
-      if(authenticated)
-    {
-      K = SHA256(S.toString(16));
-      return K;
-    }
-    else
-      session.error_message("User has not been authenticated.");
-    else
-      return K;
-  };
-
-  // If an error occurs, raise it as an alert.
-  // Developers can set this to an alternative function to handle erros differently.
-  this.error_message = function(t)
-  {
-    alert(t);
-  };
-
-
-  // exposing the remote handler so it can be modified
-  this.remote = remote;
 
 };
-  // This line is run while the document is loading
-  // It gets a list of all <script> tags and finds the last instance.
-  // The path to this script is the "src" attribute of that tag.
-  SRP.prototype.srpPath = document.getElementsByTagName('script')[document.getElementsByTagName('script').length-1].getAttribute("src");
diff --git a/lib/srp_session.js b/lib/srp_session.js
new file mode 100644
index 0000000..93bfbe5
--- /dev/null
+++ b/lib/srp_session.js
@@ -0,0 +1,138 @@
+SRP.prototype.Session = function() {
+  
+  // Variables session will be used in the SRP protocol
+  var Nstr = "115b8b692e0e045692cf280b436735c77a5a9e8a9e7ed56c965f87db5b2a2ece3";
+  var N = new BigInteger(Nstr, 16);
+  var g = new BigInteger("2");
+  var k = new BigInteger("c46d46600d87fef149bd79b81119842f3c20241fda67d06ef412d8f6d9479c58", 16);
+
+  var rng = new SecureRandom();
+  var a = new BigInteger(32, rng);
+  var A = g.modPow(a, N);
+  while(A.mod(N) == 0)
+  {
+    a = new BigInteger(32, rng);
+    A = g.modPow(a, N);
+  }
+  var Astr = A.toString(16);
+  var S = null;
+  var K = null;
+  var M = null;
+  var M2 = null;
+  var authenticated = false;
+  var I = document.getElementById("srp_username").value;
+  var pass = document.getElementById("srp_password").value;
+  var V;
+  var salt;
+
+  // *** Accessor methods ***
+
+  // allows setting the random number A for testing
+
+  this.calculateAndSetA = function(_a)
+  {
+    a = new BigInteger(_a, 16);
+    A = g.modPow(a, N);
+    Astr = A.toString(16);
+    return Astr;
+  };
+
+  this.getAstr = function() {
+    return Astr;
+  }
+
+  // Returns the user's identity
+  this.getI = function()
+  {
+    return I;
+  };
+
+  // some 16 byte random number
+  this.getSalt = function() {
+    salt = salt || new BigInteger(64, rng).toString(16);
+    return salt
+  }
+
+  // Returns the BigInteger, g
+  this.getg = function()
+  {
+    return g;
+  };
+
+  // Returns the BigInteger, N
+  this.getN = function()
+  {
+    return N;
+  };
+
+  // Calculates the X value and return it as a BigInteger
+  this.calcX = function(s)
+  {
+    return new BigInteger(SHA256(s + SHA256(I + ":" + pass)), 16);
+  };
+
+  this.getV = function(salt)
+  {
+    V = V || this.getg().modPow(this.calcX(salt), this.getN());
+    return V;
+  }
+
+  // Calculate S, M, and M2
+  // This is the client side of the SRP specification
+  this.calculations = function(salt, ephemeral)
+  {    
+    //S -> C: s | B
+    var B = new BigInteger(ephemeral, 16); 
+    var Bstr = ephemeral;
+    // u = H(A,B)
+    var u = new BigInteger(SHA256(Astr + Bstr), 16); 
+    // x = H(s, H(I:p))
+    var x = new BigInteger(SHA256(salt + SHA256(I + ":" + pass)), 16);
+    //S = (B - kg^x) ^ (a + ux)
+    var kgx = k.multiply(g.modPow(x, N));  
+    var aux = a.add(u.multiply(x)); 
+    S = B.subtract(kgx).modPow(aux, N); 
+    // M = H(H(N) xor H(g), H(I), s, A, B, K)
+    var Mstr = A.toString(16) + B.toString(16) + S.toString(16); 
+    M = SHA256(Mstr);
+    M2 = SHA256(A.toString(16) + M + S.toString(16)); 
+    //M2 = H(A, M, K)
+  };
+
+  this.getM = function() {
+    return M;
+  }
+
+  this.validate = function(serverM2) {
+    authenticated = (serverM2 && serverM2 == M2)
+    return authenticated;
+  }
+
+  // If someone wants to use the session key for encrypting traffic, they can
+  // access the key with this function.
+  this.key = function()
+  {
+    if(K) return K;
+    if(authenticated) {
+      K = SHA256(S.toString(16));
+      return K;
+    }
+    else
+      this.onError("User has not been authenticated.");
+  };
+
+  // Encrypt plaintext using slowAES
+  this.encrypt = function(plaintext)
+  {
+    var key = cryptoHelpers.toNumbers(session.key());
+    var byteMessage = cryptoHelpers.convertStringToByteArray(plaintext);
+    var iv = new Array(16);
+    rng.nextBytes(iv);
+    var paddedByteMessage = slowAES.getPaddedBlock(byteMessage, 0, byteMessage.length, slowAES.modeOfOperation.CFB);
+    var ciphertext = slowAES.encrypt(paddedByteMessage, slowAES.modeOfOperation.CFB, key, key.length, iv).cipher;
+    var retstring = cryptoHelpers.base64.encode(iv.concat(ciphertext));
+    while(retstring.indexOf("+",0) > -1)
+      retstring = retstring.replace("+", "_");
+    return retstring;
+  };
+}