util.sasl.scram: Rename variable to avoid name clash [luacheck]
[prosody.git] / util / sasl / scram.lua
index 9dd7fdf8775fc4ed413a0573c0fc896f052a780a..b3c4edc8f090ab6287b103a0a599f9ded9bcd1ad 100644 (file)
@@ -13,7 +13,6 @@
 
 local s_match = string.match;
 local type = type
-local tostring = tostring;
 local base64 = require "util.encodings".base64;
 local hmac_sha1 = require "util.hashes".hmac_sha1;
 local sha1 = require "util.hashes".sha1;
@@ -26,7 +25,7 @@ local t_concat = table.concat;
 local char = string.char;
 local byte = string.byte;
 
-module "sasl.scram"
+local _ENV = nil;
 
 --=========================
 --SASL SCRAM-SHA-1 according to RFC 5802
@@ -47,14 +46,6 @@ Supported Channel Binding Backends
 
 local default_i = 4096
 
-local function bp( b )
-       local result = ""
-       for i=1, b:len() do
-               result = result.."\\"..b:byte(i)
-       end
-       return result
-end
-
 local xor_map = {0;1;2;3;4;5;6;7;8;9;10;11;12;13;14;15;1;0;3;2;5;4;7;6;9;8;11;10;13;12;15;14;2;3;0;1;6;7;4;5;10;11;8;9;14;15;12;13;3;2;1;0;7;6;5;4;11;10;9;8;15;14;13;12;4;5;6;7;0;1;2;3;12;13;14;15;8;9;10;11;5;4;7;6;1;0;3;2;13;12;15;14;9;8;11;10;6;7;4;5;2;3;0;1;14;15;12;13;10;11;8;9;7;6;5;4;3;2;1;0;15;14;13;12;11;10;9;8;8;9;10;11;12;13;14;15;0;1;2;3;4;5;6;7;9;8;11;10;13;12;15;14;1;0;3;2;5;4;7;6;10;11;8;9;14;15;12;13;2;3;0;1;6;7;4;5;11;10;9;8;15;14;13;12;3;2;1;0;7;6;5;4;12;13;14;15;8;9;10;11;4;5;6;7;0;1;2;3;13;12;15;14;9;8;11;10;5;4;7;6;1;0;3;2;14;15;12;13;10;11;8;9;6;7;4;5;2;3;0;1;15;14;13;12;11;10;9;8;7;6;5;4;3;2;1;0;};
 
 local result = {};
@@ -96,7 +87,7 @@ local function hashprep(hashname)
        return hashname:lower():gsub("-", "_");
 end
 
-function getAuthenticationDatabaseSHA1(password, salt, iteration_count)
+local function getAuthenticationDatabaseSHA1(password, salt, iteration_count)
        if type(password) ~= "string" or type(salt) ~= "string" or type(iteration_count) ~= "number" then
                return false, "inappropriate argument types"
        end
@@ -110,22 +101,20 @@ function getAuthenticationDatabaseSHA1(password, salt, iteration_count)
 end
 
 local function scram_gen(hash_name, H_f, HMAC_f)
+       local profile_name = "scram_" .. hashprep(hash_name);
        local function scram_hash(self, message)
-               if not self.state then self["state"] = {} end
                local support_channel_binding = false;
                if self.profile.cb then support_channel_binding = true; end
 
                if type(message) ~= "string" or #message == 0 then return "failure", "malformed-request" end
-               if not self.state.name then
+               local state = self.state;
+               if not state then
                        -- we are processing client_first_message
                        local client_first_message = message;
 
                        -- TODO: fail if authzid is provided, since we don't support them yet
-                       self.state["client_first_message"] = client_first_message;
-                       self.state["gs2_cbind_flag"], self.state["gs2_cbind_name"], self.state["authzid"], self.state["name"], self.state["clientnonce"]
-                               = client_first_message:match("^([ynp])=?([%a%-]*),(.*),n=(.*),r=([^,]*).*");
-
-                       local gs2_cbind_flag = self.state.gs2_cbind_flag;
+                       local gs2_header, gs2_cbind_flag, gs2_cbind_name, authzid, client_first_message_bare, username, clientnonce
+                               = s_match(client_first_message, "^(([pny])=?([^,]*),([^,]*),)(m?=?[^,]*,?n=([^,]*),r=([^,]*),?.*)$");
 
                        if not gs2_cbind_flag then
                                return "failure", "malformed-request";
@@ -144,31 +133,26 @@ local function scram_gen(hash_name, H_f, HMAC_f)
 
                        if support_channel_binding and gs2_cbind_flag == "p" then
                                -- check whether we support the proposed channel binding type
-                               if not self.profile.cb[self.state.gs2_cbind_name] then
+                               if not self.profile.cb[gs2_cbind_name] then
                                        return "failure", "malformed-request", "Proposed channel binding type isn't supported.";
                                end
                        else
                                -- no channel binding,
-                               self.state.gs2_cbind_name = nil;
+                               gs2_cbind_name = nil;
                        end
 
-                       if not self.state.name or not self.state.clientnonce then
-                               return "failure", "malformed-request", "Channel binding isn't support at this time.";
-                       end
-
-                       self.state.name = validate_username(self.state.name, self.profile.nodeprep);
-                       if not self.state.name then
+                       username = validate_username(username, self.profile.nodeprep);
+                       if not username then
                                log("debug", "Username violates either SASLprep or contains forbidden character sequences.")
                                return "failure", "malformed-request", "Invalid username.";
                        end
 
-                       self.state["servernonce"] = generate_uuid();
-
                        -- retreive credentials
+                       local stored_key, server_key, salt, iteration_count;
                        if self.profile.plain then
-                               local password, state = self.profile.plain(self, self.state.name, self.realm)
-                               if state == nil then return "failure", "not-authorized"
-                               elseif state == false then return "failure", "account-disabled" end
+                               local password, status = self.profile.plain(self, username, self.realm)
+                               if status == nil then return "failure", "not-authorized"
+                               elseif status == false then return "failure", "account-disabled" end
 
                                password = saslprep(password);
                                if not password then
@@ -176,64 +160,72 @@ local function scram_gen(hash_name, H_f, HMAC_f)
                                        return "failure", "not-authorized", "Invalid password."
                                end
 
-                               self.state.salt = generate_uuid();
-                               self.state.iteration_count = default_i;
+                               salt = generate_uuid();
+                               iteration_count = default_i;
 
                                local succ = false;
-                               succ, self.state.stored_key, self.state.server_key = getAuthenticationDatabaseSHA1(password, self.state.salt, default_i, self.state.iteration_count);
+                               succ, stored_key, server_key = getAuthenticationDatabaseSHA1(password, salt, iteration_count);
                                if not succ then
-                                       log("error", "Generating authentication database failed. Reason: %s", self.state.stored_key);
+                                       log("error", "Generating authentication database failed. Reason: %s", stored_key);
                                        return "failure", "temporary-auth-failure";
                                end
-                       elseif self.profile["scram_"..hashprep(hash_name)] then
-                               local stored_key, server_key, iteration_count, salt, state = self.profile["scram_"..hashprep(hash_name)](self, self.state.name, self.realm);
+                       elseif self.profile[profile_name] then
+                               local status;
+                               stored_key, server_key, iteration_count, salt, status = self.profile[profile_name](self, username, self.realm);
                                if state == nil then return "failure", "not-authorized"
                                elseif state == false then return "failure", "account-disabled" end
-
-                               self.state.stored_key = stored_key;
-                               self.state.server_key = server_key;
-                               self.state.iteration_count = iteration_count;
-                               self.state.salt = salt
                        end
 
-                       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;
+                       local nonce = clientnonce .. generate_uuid();
+                       local server_first_message = "r="..nonce..",s="..base64.encode(salt)..",i="..iteration_count;
+                       self.state = {
+                               gs2_header = gs2_header;
+                               gs2_cbind_name = gs2_cbind_name;
+                               username = username;
+                               nonce = nonce;
+
+                               server_key = server_key;
+                               stored_key = stored_key;
+                               client_first_message_bare = client_first_message_bare;
+                               server_first_message = server_first_message;
+                       }
                        return "challenge", server_first_message
                else
                        -- we are processing client_final_message
                        local client_final_message = message;
 
-                       self.state["channelbinding"], self.state["nonce"], self.state["proof"] = client_final_message:match("^c=(.*),r=(.*),.*p=(.*)");
+                       local client_final_message_without_proof, channelbinding, nonce, proof
+                               = s_match(client_final_message, "(c=([^,]*),r=([^,]*),?.-),p=(.*)$");
 
-                       if not self.state.proof or not self.state.nonce or not self.state.channelbinding then
+                       if not proof or not nonce or not channelbinding then
                                return "failure", "malformed-request", "Missing an attribute(p, r or c) in SASL message.";
                        end
 
-                       if self.state.gs2_cbind_name then
+                       local client_gs2_header = base64.decode(channelbinding)
+                       local our_client_gs2_header = state["gs2_header"]
+                       if state.gs2_cbind_name then
                                -- we support channelbinding, so check if the value is valid
-                               local client_gs2_header = base64.decode(self.state.channelbinding)
-                               local our_client_gs2_header = "p="..self.state.gs2_cbind_name..","..self.state["authzid"]..","..self.profile.cb[self.state.gs2_cbind_name](self);
-
-                               if client_gs2_header ~= our_client_gs2_header then
-                                       return "failure", "malformed-request", "Invalid channel binding value.";
-                               end
+                               our_client_gs2_header = our_client_gs2_header .. self.profile.cb[state.gs2_cbind_name](self);
+                       end
+                       if client_gs2_header ~= our_client_gs2_header then
+                               return "failure", "malformed-request", "Invalid channel binding value.";
                        end
 
-                       if self.state.nonce ~= self.state.clientnonce..self.state.servernonce then
+                       if nonce ~= state.nonce then
                                return "failure", "malformed-request", "Wrong nonce in client-final-message.";
                        end
 
-                       local ServerKey = self.state.server_key;
-                       local StoredKey = self.state.stored_key;
+                       local ServerKey = state.server_key;
+                       local StoredKey = state.stored_key;
 
-                       local AuthMessage = "n=" .. s_match(self.state.client_first_message,"n=(.+)") .. "," .. self.state.server_first_message .. "," .. s_match(client_final_message, "(.+),p=.+")
+                       local AuthMessage = state.client_first_message_bare .. "," .. state.server_first_message .. "," .. client_final_message_without_proof
                        local ClientSignature = HMAC_f(StoredKey, AuthMessage)
-                       local ClientKey = binaryXOR(ClientSignature, base64.decode(self.state.proof))
+                       local ClientKey = binaryXOR(ClientSignature, base64.decode(proof))
                        local ServerSignature = HMAC_f(ServerKey, AuthMessage)
 
                        if StoredKey == H_f(ClientKey) then
                                local server_final_message = "v="..base64.encode(ServerSignature);
-                               self["username"] = self.state.name;
+                               self["username"] = state.username;
                                return "success", server_final_message;
                        else
                                return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";
@@ -243,7 +235,7 @@ local function scram_gen(hash_name, H_f, HMAC_f)
        return scram_hash;
 end
 
-function init(registerMechanism)
+local function init(registerMechanism)
        local function registerSCRAMMechanism(hash_name, hash, hmac_hash)
                registerMechanism("SCRAM-"..hash_name, {"plain", "scram_"..(hashprep(hash_name))}, scram_gen(hash_name:lower(), hash, hmac_hash));
 
@@ -254,4 +246,7 @@ function init(registerMechanism)
        registerSCRAMMechanism("SHA-1", sha1, hmac_sha1);
 end
 
-return _M;
+return {
+       getAuthenticationDatabaseSHA1 = getAuthenticationDatabaseSHA1;
+       init = init;
+}