util.sasl: Abstracting out the hash function used since SCRAM is independent of it...

diff --git a/util/sasl/scram.lua b/util/sasl/scram.lua
index 103e8a905d65373efb062cdd5020495773760e75..43b97c55d33a67816e267043ca78bad87b1f6354 100644 (file)
--- a/util/sasl/scram.lua
+++ b/util/sasl/scram.lua
@@ -82,77 +82,95 @@ local function validate_username(username)
        return username;
 end
 
-local function scram_sha_1(self, message)
-       if not self.state then self["state"] = {} end
+local function scram_gen(hash_name, H_f, HMAC_f)
+       local function scram_hash(self, message)
+               if not self.state then self["state"] = {} end
        
-       if not self.state.name then
-               -- we are processing client_first_message
-               local client_first_message = message;
-               self.state["client_first_message"] = client_first_message;
-               self.state["name"] = client_first_message:match("n=(.+),r=")
-               self.state["clientnonce"] = client_first_message:match("r=([^,]+)")
-               
-               if not self.state.name or not self.state.clientnonce then
-                       return "failure", "malformed-request";
-               end
-               
-               self.state.name = validate_username(self.state.name);
                if not self.state.name then
-                       log("debug", "Username violates either SASLprep or contains forbidden character sequences.")
-                       return "failure", "malformed-request", "Invalid username.";
-               end
+                       -- we are processing client_first_message
+                       local client_first_message = message;
+                       self.state["client_first_message"] = client_first_message;
+                       self.state["name"] = client_first_message:match("n=(.+),r=")
+                       self.state["clientnonce"] = client_first_message:match("r=([^,]+)")
                
-               self.state["servernonce"] = generate_uuid();
-               self.state["salt"] = generate_uuid();
+                       if not self.state.name or not self.state.clientnonce then
+                               return "failure", "malformed-request";
+                       end
                
-               local server_first_message = "r="..self.state.clientnonce..self.state.servernonce..",s="..base64.encode(self.state.salt)..",i="..default_i;
-               self.state["server_first_message"] = server_first_message;
-               return "challenge", server_first_message
-       else
-               if type(message) ~= "string" then return "failure", "malformed-request" end
-               -- we are processing client_final_message
-               local client_final_message = message;
+                       self.state.name = validate_username(self.state.name);
+                       if not self.state.name then
+                               log("debug", "Username violates either SASLprep or contains forbidden character sequences.")
+                               return "failure", "malformed-request", "Invalid username.";
+                       end
                
-               self.state["proof"] = client_final_message:match("p=(.+)");
-               self.state["nonce"] = client_final_message:match("r=(.+),p=");
-               self.state["channelbinding"] = client_final_message:match("c=(.+),r=");
-               if not self.state.proof or not self.state.nonce or not self.state.channelbinding then
-                       return "failure", "malformed-request", "Missing an attribute(p, r or c) in SASL message.";
-               end
+                       self.state["servernonce"] = generate_uuid();
+                       
+                       -- retreive credentials
+                       if self.profile.plain then
+                               password, state = self.profile.plain(self.state.name, self.realm)
+                               if state == nil then return "failure", "not-authorized"
+                               elseif state == false then return "failure", "account-disabled" end
+                               
+                               password = saslprep(password);
+                               if not password then
+                                       log("debug", "Password violates SASLprep.");
+                                       return "failure", "not-authorized", "Invalid password."
+                               end
+                               self.state.salt = generate_uuid();
+                               self.state.iteration_count = default_i;
+                               self.state.salted_password = Hi(HMAC_f, password, self.state.salt, default_i);
+                       elseif self.profile["scram-"..hash_name] then
+                               salted_password, iteration_count, salt, state = self.profile["scram-"..hash_name](self.state.name, self.realm);
+                               if state == nil then return "failure", "not-authorized"
+                               elseif state == false then return "failure", "account-disabled" end
+                               
+                               self.state.salted_password = salted_password;
+                               self.state.iteration_count = iteration_count;
+                               self.state.salt = salt
+                       end
                
-               local password, state;
-               if self.profile.plain then
-                       password, state = self.profile.plain(self.state.name, self.realm)
-                       if state == nil then return "failure", "not-authorized"
-                       elseif state == false then return "failure", "account-disabled" end
-                       password = saslprep(password);
-                       if not password then
-                               log("debug", "Password violates SASLprep.");
-                               return "failure", "not-authorized", "Invalid password."
+                       local server_first_message = "r="..self.state.clientnonce..self.state.servernonce..",s="..base64.encode(self.state.salt)..",i="..self.state.iteration_count;
+                       self.state["server_first_message"] = server_first_message;
+                       return "challenge", server_first_message
+               else
+                       if type(message) ~= "string" then return "failure", "malformed-request" end
+                       -- we are processing client_final_message
+                       local client_final_message = message;
+               
+                       self.state["proof"] = client_final_message:match("p=(.+)");
+                       self.state["nonce"] = client_final_message:match("r=(.+),p=");
+                       self.state["channelbinding"] = client_final_message:match("c=(.+),r=");
+                       if not self.state.proof or not self.state.nonce or not self.state.channelbinding then
+                               return "failure", "malformed-request", "Missing an attribute(p, r or c) in SASL message.";
                        end
-               end
                
-               local SaltedPassword = Hi(hmac_sha1, password, self.state.salt, default_i)
-               local ClientKey = hmac_sha1(SaltedPassword, "Client Key")
-               local ServerKey = hmac_sha1(SaltedPassword, "Server Key")
-               local StoredKey = sha1(ClientKey)
-               local AuthMessage = "n=" .. s_match(self.state.client_first_message,"n=(.+)") .. "," .. self.state.server_first_message .. "," .. s_match(client_final_message, "(.+),p=.+")
-               local ClientSignature = hmac_sha1(StoredKey, AuthMessage)
-               local ClientProof     = binaryXOR(ClientKey, ClientSignature)
-               local ServerSignature = hmac_sha1(ServerKey, AuthMessage)
+                       local SaltedPassword = self.state.salted_password;
+                       local ClientKey = HMAC_f(SaltedPassword, "Client Key")
+                       local ServerKey = HMAC_f(SaltedPassword, "Server Key")
+                       local StoredKey = H_f(ClientKey)
+                       local AuthMessage = "n=" .. s_match(self.state.client_first_message,"n=(.+)") .. "," .. self.state.server_first_message .. "," .. s_match(client_final_message, "(.+),p=.+")
+                       local ClientSignature = HMAC_f(StoredKey, AuthMessage)
+                       local ClientProof     = binaryXOR(ClientKey, ClientSignature)
+                       local ServerSignature = HMAC_f(ServerKey, AuthMessage)
                
-               if base64.encode(ClientProof) == self.state.proof then
-                       local server_final_message = "v="..base64.encode(ServerSignature);
-                       self["username"] = self.state.name;
-                       return "success", server_final_message;
-               else
-                       return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";
+                       if base64.encode(ClientProof) == self.state.proof then
+                               local server_final_message = "v="..base64.encode(ServerSignature);
+                               self["username"] = self.state.name;
+                               return "success", server_final_message;
+                       else
+                               return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";
+                       end
                end
        end
+       return scram_hash;
 end
 
 function init(registerMechanism)
-       registerMechanism("SCRAM-SHA-1", {"plain"}, scram_sha_1);
+       local function registerSCRAMMechanism(hash_name, hash, hmac_hash)
+               registerMechanism("SCRAM-"..hash_name, {"plain", "scram-"..(hash_name:lower())}, scram_gen(hash_name:lower(), hash, hmac_hash));
+       end
+       
+       registerSCRAMMechanism("SHA-1", sha1, hmac_sha1);
 end
 
 return _M;
\ No newline at end of file