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prosody
Changeset
2183:44e71e65da86 sasl
Importing SASL Digest-MD5 code. Now for real.
author | Tobias Markmann <tm@ayena.de> |
---|---|
date | Fri, 28 Aug 2009 19:57:09 +0200 (2009-08-28) |
parents | 2182:27c7d287345e |
children | 2184:0d1740f7b6e8 |
files | util/sasl.lua |
diffstat | 1 files changed, 182 insertions(+), 0 deletions(-) [+] |
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--- a/util/sasl.lua Fri Aug 28 19:56:54 2009 +0200 +++ b/util/sasl.lua Fri Aug 28 19:57:09 2009 +0200 @@ -151,4 +151,186 @@ --========================= --SASL DIGEST-MD5 according to RFC 2831 +local function new_digest_md5(realm, credentials_handler) + --TODO complete support for authzid + + local function serialize(message) + local data = "" + + if type(message) ~= "table" then error("serialize needs an argument of type table.") end + + -- testing all possible values + if message["realm"] then data = data..[[realm="]]..message.realm..[[",]] end + if message["nonce"] then data = data..[[nonce="]]..message.nonce..[[",]] end + if message["qop"] then data = data..[[qop="]]..message.qop..[[",]] end + if message["charset"] then data = data..[[charset=]]..message.charset.."," end + if message["algorithm"] then data = data..[[algorithm=]]..message.algorithm.."," end + if message["rspauth"] then data = data..[[rspauth=]]..message.rspauth.."," end + data = data:gsub(",$", "") + return data + end + + local function utf8tolatin1ifpossible(passwd) + local i = 1; + while i <= #passwd do + local passwd_i = to_byte(passwd:sub(i, i)); + if passwd_i > 0x7F then + if passwd_i < 0xC0 or passwd_i > 0xC3 then + return passwd; + end + i = i + 1; + passwd_i = to_byte(passwd:sub(i, i)); + if passwd_i < 0x80 or passwd_i > 0xBF then + return passwd; + end + end + i = i + 1; + end + + local p = {}; + local j = 0; + i = 1; + while (i <= #passwd) do + local passwd_i = to_byte(passwd:sub(i, i)); + if passwd_i > 0x7F then + i = i + 1; + local passwd_i_1 = to_byte(passwd:sub(i, i)); + t_insert(p, to_char(passwd_i%4*64 + passwd_i_1%64)); -- I'm so clever + else + t_insert(p, to_char(passwd_i)); + end + i = i + 1; + end + return t_concat(p); + end + local function latin1toutf8(str) + local p = {}; + for ch in gmatch(str, ".") do + ch = to_byte(ch); + if (ch < 0x80) then + t_insert(p, to_char(ch)); + elseif (ch < 0xC0) then + t_insert(p, to_char(0xC2, ch)); + else + t_insert(p, to_char(0xC3, ch - 64)); + end + end + return t_concat(p); + end + local function parse(data) + local message = {} + for k, v in gmatch(data, [[([%w%-]+)="?([^",]*)"?,?]]) do -- FIXME The hacky regex makes me shudder + message[k] = v; + end + return message; + end + + local object = { mechanism = "DIGEST-MD5", realm = realm, credentials_handler = credentials_handler}; + + object.nonce = generate_uuid(); + object.step = 0; + object.nonce_count = {}; + + function object.feed(self, message) + self.step = self.step + 1; + if (self.step == 1) then + local challenge = serialize({ nonce = object.nonce, + qop = "auth", + charset = "utf-8", + algorithm = "md5-sess", + realm = self.realm}); + return "challenge", challenge; + elseif (self.step == 2) then + local response = parse(message); + -- check for replay attack + if response["nc"] then + if self.nonce_count[response["nc"]] then return "failure", "not-authorized" end + end + + -- check for username, it's REQUIRED by RFC 2831 + if not response["username"] then + return "failure", "malformed-request"; + end + self["username"] = response["username"]; + + -- check for nonce, ... + if not response["nonce"] then + return "failure", "malformed-request"; + else + -- check if it's the right nonce + if response["nonce"] ~= tostring(self.nonce) then return "failure", "malformed-request" end + end + + if not response["cnonce"] then return "failure", "malformed-request", "Missing entry for cnonce in SASL message." end + if not response["qop"] then response["qop"] = "auth" end + + if response["realm"] == nil or response["realm"] == "" then + response["realm"] = ""; + elseif response["realm"] ~= self.realm then + return "failure", "not-authorized", "Incorrect realm value"; + end + + local decoder; + if response["charset"] == nil then + decoder = utf8tolatin1ifpossible; + elseif response["charset"] ~= "utf-8" then + return "failure", "incorrect-encoding", "The client's response uses "..response["charset"].." for encoding with isn't supported by sasl.lua. Supported encodings are latin or utf-8."; + end + + local domain = ""; + local protocol = ""; + if response["digest-uri"] then + protocol, domain = response["digest-uri"]:match("(%w+)/(.*)$"); + if protocol == nil or domain == nil then return "failure", "malformed-request" end + else + return "failure", "malformed-request", "Missing entry for digest-uri in SASL message." + end + + --TODO maybe realm support + self.username = response["username"]; + local password_encoding, Y = self.credentials_handler("DIGEST-MD5", response["username"], self.realm, response["realm"], decoder); + if Y == nil then return "failure", "not-authorized" + elseif Y == false then return "failure", "account-disabled" end + local A1 = ""; + if response.authzid then + if response.authzid == self.username.."@"..self.realm then + -- COMPAT + log("warn", "Client is violating XMPP RFC. See section 6.1 of RFC 3920."); + A1 = Y..":"..response["nonce"]..":"..response["cnonce"]..":"..response.authzid; + else + A1 = "?"; + end + else + A1 = Y..":"..response["nonce"]..":"..response["cnonce"]; + end + local A2 = "AUTHENTICATE:"..protocol.."/"..domain; + + local HA1 = md5(A1, true); + local HA2 = md5(A2, true); + + local KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2; + local response_value = md5(KD, true); + + if response_value == response["response"] then + -- calculate rspauth + A2 = ":"..protocol.."/"..domain; + + HA1 = md5(A1, true); + HA2 = md5(A2, true); + + KD = HA1..":"..response["nonce"]..":"..response["nc"]..":"..response["cnonce"]..":"..response["qop"]..":"..HA2 + local rspauth = md5(KD, true); + self.authenticated = true; + return "challenge", serialize({rspauth = rspauth}); + else + return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated." + end + elseif self.step == 3 then + if self.authenticated ~= nil then return "success" + else return "failure", "malformed-request" end + end + end + return object; +end + return _M;