diff options
Diffstat (limited to 'util/sasl/scram.lua')
| -rw-r--r-- | util/sasl/scram.lua | 79 |
1 files changed, 60 insertions, 19 deletions
diff --git a/util/sasl/scram.lua b/util/sasl/scram.lua index cf2f0ede..9dd7fdf8 100644 --- a/util/sasl/scram.lua +++ b/util/sasl/scram.lua @@ -13,7 +13,7 @@ local s_match = string.match; local type = type -local string = string +local tostring = tostring; local base64 = require "util.encodings".base64; local hmac_sha1 = require "util.hashes".hmac_sha1; local sha1 = require "util.hashes".sha1; @@ -39,6 +39,10 @@ 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 @@ -73,11 +77,11 @@ 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); @@ -108,40 +112,64 @@ 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 - + 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 -- 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=([^,]*).*"); + 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=([^,]*).*"); - -- we don't do any channel binding yet - if self.state.gs2_cbind_flag ~= "n" and self.state.gs2_cbind_flag ~= "y" then + local gs2_cbind_flag = self.state.gs2_cbind_flag; + + if not gs2_cbind_flag then return "failure", "malformed-request"; end + 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 + + 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 + return "failure", "malformed-request", "Proposed channel binding type isn't supported."; + end + else + -- no channel binding, + self.state.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 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 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 - + password = saslprep(password); if not password then log("debug", "Password violates SASLprep."); @@ -161,33 +189,43 @@ local function scram_gen(hash_name, H_f, HMAC_f) local stored_key, server_key, iteration_count, salt, state = self.profile["scram_"..hashprep(hash_name)](self, self.state.name, 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; 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 return "failure", "malformed-request", "Missing an attribute(p, r or c) in SASL message."; end + if self.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 + end + if self.state.nonce ~= self.state.clientnonce..self.state.servernonce 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 ClientSignature = HMAC_f(StoredKey, AuthMessage) local ClientKey = binaryXOR(ClientSignature, base64.decode(self.state.proof)) @@ -208,6 +246,9 @@ 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); |