X-Git-Url: https://git.enpas.org/?a=blobdiff_plain;f=util%2Fsasl%2Fscram.lua;h=0d2852bf8141d9d22c7fef8c38393378e5dfb487;hb=a2fc95c857560f2c3221afcb0967f82fbbf3ce93;hp=6040c402ae8b94aaae5c8e29aac3baaeaaa6d9ce;hpb=9bd553f671cd8abcd19704598f1d66e4d6eebae5;p=prosody.git diff --git a/util/sasl/scram.lua b/util/sasl/scram.lua index 6040c402..0d2852bf 100644 --- a/util/sasl/scram.lua +++ b/util/sasl/scram.lua @@ -13,41 +13,39 @@ local s_match = string.match; local type = type -local string = string local base64 = require "util.encodings".base64; -local hmac_sha1 = require "util.hmac".sha1; +local hmac_sha1 = require "util.hashes".hmac_sha1; local sha1 = require "util.hashes".sha1; +local Hi = require "util.hashes".scram_Hi_sha1; local generate_uuid = require "util.uuid".generate; local saslprep = require "util.encodings".stringprep.saslprep; +local nodeprep = require "util.encodings".stringprep.nodeprep; local log = require "util.logger".init("sasl"); local t_concat = table.concat; local char = string.char; local byte = string.byte; -module "scram" +module "sasl.scram" --========================= ---SASL SCRAM-SHA-1 according to draft-ietf-sasl-scram-10 +--SASL SCRAM-SHA-1 according to RFC 5802 --[[ Supported Authentication Backends -scram-{MECH}: +scram_{MECH}: + -- MECH being a standard hash name (like those at IANA's hash registry) with '-' replaced with '_' function(username, realm) - return salted_password, iteration_count, salt, state; + 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 = {}; @@ -63,138 +61,171 @@ local function binaryXOR( a, b ) return t_concat(result); end --- hash algorithm independent Hi(PBKDF2) implementation -local function Hi(hmac, str, salt, i) - local Ust = hmac(str, salt.."\0\0\0\1"); - local res = Ust; - for n=1,i-1 do - local Und = hmac(str, Ust) - res = binaryXOR(res, Und) - Ust = Und - end - return res -end - -local function validate_username(username) +local function validate_username(username, _nodeprep) -- check for forbidden char sequences for eq in username:gmatch("=(.?.?)") do - if eq ~= "2D" and eq ~= "3D" then - return false - end + if eq ~= "2C" and eq ~= "3D" then + return false + end end - - -- replace =2D with , and =3D with = - username = username:gsub("=2D", ","); + + -- replace =2C with , and =3D with = + username = username:gsub("=2C", ","); username = username:gsub("=3D", "="); - + -- apply SASLprep username = saslprep(username); - return username; + + if username and _nodeprep ~= false then + username = (_nodeprep or nodeprep)(username); + end + + return username and #username>0 and username; end -function saltedPasswordSHA1(password, salt, iteration_count) - local salted_password - if type(password) ~= "string" and type(salt) ~= "string" and type(iteration_count) ~= "number" then +local function hashprep(hashname) + return hashname:lower():gsub("-", "_"); +end + +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 if iteration_count < 4096 then - log("warning", "Iteration count < 4096 which is the suggested minimum according to RFC 5802.") + log("warn", "Iteration count < 4096 which is the suggested minimum according to RFC 5802.") end - - return true, Hi(hmac_sha1, password, salt, iteration_count); + local salted_password = Hi(password, salt, iteration_count); + local stored_key = sha1(hmac_sha1(salted_password, "Client Key")) + local server_key = hmac_sha1(salted_password, "Server Key"); + return true, stored_key, server_key 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); - 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.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.salted_password = saltedPasswordSHA1(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 salted password failed. Reason: %s", self.state.salted_password); + log("error", "Generating authentication database failed. Reason: %s", stored_key); return "failure", "temporary-auth-failure"; end - elseif self.profile["scram_"..hash_name] then - local salted_password, iteration_count, salt, state = self.profile["scram-"..hash_name](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.salted_password = salted_password; - 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 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 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 ClientProof = binaryXOR(ClientKey, ClientSignature) + local ClientKey = binaryXOR(ClientSignature, base64.decode(proof)) local ServerSignature = HMAC_f(ServerKey, AuthMessage) - if base64.encode(ClientProof) == self.state.proof then + 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."; @@ -206,7 +237,10 @@ end function init(registerMechanism) 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)); + 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);