diff options
Diffstat (limited to 'util/sasl/scram.lua')
| -rw-r--r-- | util/sasl/scram.lua | 145 |
1 files changed, 89 insertions, 56 deletions
diff --git a/util/sasl/scram.lua b/util/sasl/scram.lua index cf2f0ede..0d2852bf 100644 --- a/util/sasl/scram.lua +++ b/util/sasl/scram.lua @@ -13,7 +13,6 @@ local s_match = string.match; local type = type -local string = string local base64 = require "util.encodings".base64; local hmac_sha1 = require "util.hashes".hmac_sha1; local sha1 = require "util.hashes".sha1; @@ -39,18 +38,14 @@ scram_{MECH}: function(username, realm) return stored_key, server_key, iteration_count, salt, state; end + +Supported Channel Binding Backends + +'tls-unique' according to RFC 5929 ]] 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 = {}; @@ -73,11 +68,11 @@ local function validate_username(username, _nodeprep) return false end end - + -- replace =2C with , and =3D with = username = username:gsub("=2C", ","); username = username:gsub("=3D", "="); - + -- apply SASLprep username = saslprep(username); @@ -106,96 +101,131 @@ 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["authzid"], self.state["name"], self.state["clientnonce"] - = client_first_message:match("^(%a),(.*),n=(.*),r=([^,]*).*"); + 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=([^,]*),?.*)$"); - -- we don't do any channel binding yet - if self.state.gs2_cbind_flag ~= "n" and self.state.gs2_cbind_flag ~= "y" then + if not gs2_cbind_flag then return "failure", "malformed-request"; end - if not self.state.name or not self.state.clientnonce then - return "failure", "malformed-request", "Channel binding isn't support at this time."; + if support_channel_binding and gs2_cbind_flag == "y" then + -- "y" -> client does support channel binding + -- but thinks the server does not. + return "failure", "malformed-request"; + end + + if gs2_cbind_flag == "n" then + -- "n" -> client doesn't support channel binding. + support_channel_binding = false; end - - self.state.name = validate_username(self.state.name, self.profile.nodeprep); - if not self.state.name then + + if support_channel_binding and gs2_cbind_flag == "p" then + -- check whether we support the proposed channel binding type + 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, + gs2_cbind_name = nil; + end + + 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) + local password, state = self.profile.plain(self, username, 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; + 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 state; + stored_key, server_key, iteration_count, salt, state = 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=(.*)"); - - if not self.state.proof or not self.state.nonce or not self.state.channelbinding then + + local client_final_message_without_proof, channelbinding, nonce, proof + = s_match(client_final_message, "(c=([^,]*),r=([^,]*),?.-),p=(.*)$"); + + 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.nonce ~= self.state.clientnonce..self.state.servernonce 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 + 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 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 AuthMessage = "n=" .. s_match(self.state.client_first_message,"n=(.+)") .. "," .. self.state.server_first_message .. "," .. s_match(client_final_message, "(.+),p=.+") + + local ServerKey = state.server_key; + local StoredKey = state.stored_key; + + 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."; @@ -208,6 +238,9 @@ end 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)); + + -- register channel binding equivalent + registerMechanism("SCRAM-"..hash_name.."-PLUS", {"plain", "scram_"..(hashprep(hash_name))}, scram_gen(hash_name:lower(), hash, hmac_hash), {"tls-unique"}); end registerSCRAMMechanism("SHA-1", sha1, hmac_sha1); |