diff options
| -rw-r--r-- | core/s2smanager.lua | 38 | ||||
| -rw-r--r-- | plugins/mod_dialback.lua | 14 | ||||
| -rw-r--r-- | plugins/mod_saslauth.lua | 132 | ||||
| -rw-r--r-- | util/certverification.lua | 211 |
4 files changed, 391 insertions, 4 deletions
diff --git a/core/s2smanager.lua b/core/s2smanager.lua index c6e6df8e..be5c04fc 100644 --- a/core/s2smanager.lua +++ b/core/s2smanager.lua @@ -27,6 +27,7 @@ local modulemanager = require "core.modulemanager"; local st = require "stanza"; local stanza = st.stanza; local nameprep = require "util.encodings".stringprep.nameprep; +local cert_verify_identity = require "util.certverification".verify_identity; local fire_event = prosody.events.fire_event; local uuid_gen = require "util.uuid".generate; @@ -373,16 +374,44 @@ function session_open_stream(session, from, to) from=from, to=to, version='1.0', ["xml:lang"]='en'}):top_tag()); end +local function check_cert_status(session) + local conn = session.conn:socket() + local cert = conn:getpeercertificate() + + if cert then + local chain_valid, err = conn:getpeerchainvalid() + if not chain_valid then + session.cert_chain_status = "invalid"; + (session.log or log)("debug", "certificate chain validation result: %s", err); + else + session.cert_chain_status = "valid"; + + local host = session.direction == "incoming" and session.from_host or session.to_host + + -- We'll go ahead and verify the asserted identity if the + -- connecting server specified one. + if host then + if cert_verify_identity(host, "xmpp-server", cert) then + session.cert_identity_status = "valid" + else + session.cert_identity_status = "invalid" + end + end + end + end +end + function streamopened(session, attr) local send = session.sends2s; -- TODO: #29: SASL/TLS on s2s streams session.version = tonumber(attr.version) or 0; + -- TODO: Rename session.secure to session.encrypted if session.secure == false then session.secure = true; end - + if session.direction == "incoming" then -- Send a reply stream header session.to_host = attr.to and nameprep(attr.to); @@ -407,6 +436,9 @@ function streamopened(session, attr) return; end end + + if session.secure and not session.cert_chain_status then check_cert_status(session); end + send("<?xml version='1.0'?>"); send(stanza("stream:stream", { xmlns='jabber:server', ["xmlns:db"]='jabber:server:dialback', ["xmlns:stream"]='http://etherx.jabber.org/streams', id=session.streamid, from=session.to_host, to=session.from_host, version=(session.version > 0 and "1.0" or nil) }):top_tag()); @@ -426,7 +458,9 @@ function streamopened(session, attr) -- If we are just using the connection for verifying dialback keys, we won't try and auth it if not attr.id then error("stream response did not give us a streamid!!!"); end session.streamid = attr.id; - + + if session.secure and not session.cert_chain_status then check_cert_status(session); end + -- Send unauthed buffer -- (stanzas which are fine to send before dialback) -- Note that this is *not* the stanza queue (which diff --git a/plugins/mod_dialback.lua b/plugins/mod_dialback.lua index e1fd5a42..a8923e27 100644 --- a/plugins/mod_dialback.lua +++ b/plugins/mod_dialback.lua @@ -132,9 +132,19 @@ module:hook("stanza/jabber:server:dialback:result", function(event) end end); +module:hook_stanza("urn:ietf:params:xml:ns:xmpp-sasl", "failure", function (origin, stanza) + if origin.external_auth == "failed" then + module:log("debug", "SASL EXTERNAL failed, falling back to dialback"); + s2s_initiate_dialback(origin); + return true; + end +end, 100); + module:hook_stanza(xmlns_stream, "features", function (origin, stanza) - s2s_initiate_dialback(origin); - return true; + if not origin.external_auth or origin.external_auth == "failed" then + s2s_initiate_dialback(origin); + return true; + end end, 100); -- Offer dialback to incoming hosts diff --git a/plugins/mod_saslauth.lua b/plugins/mod_saslauth.lua index c6ead31a..37b2720b 100644 --- a/plugins/mod_saslauth.lua +++ b/plugins/mod_saslauth.lua @@ -11,8 +11,11 @@ local st = require "util.stanza"; local sm_bind_resource = require "core.sessionmanager".bind_resource; local sm_make_authenticated = require "core.sessionmanager".make_authenticated; +local s2s_make_authenticated = require "core.s2smanager".make_authenticated; local base64 = require "util.encodings".base64; +local cert_verify_identity = require "util.certverification".verify_identity; + local nodeprep = require "util.encodings".stringprep.nodeprep; local usermanager_get_sasl_handler = require "core.usermanager".get_sasl_handler; local t_concat, t_insert = table.concat, table.insert; @@ -91,8 +94,123 @@ local function sasl_process_cdata(session, stanza) return true; end +module:hook_stanza(xmlns_sasl, "success", function (session, stanza) + if session.type ~= "s2sout_unauthed" or session.external_auth ~= "attempting" then return; end + module:log("debug", "SASL EXTERNAL with %s succeeded", session.to_host); + session.external_auth = "succeeded" + session:reset_stream(); + + local default_stream_attr = {xmlns = "jabber:server", ["xmlns:stream"] = "http://etherx.jabber.org/streams", + ["xmlns:db"] = 'jabber:server:dialback', version = "1.0", to = session.to_host, from = session.from_host}; + session.sends2s("<?xml version='1.0'?>"); + session.sends2s(st.stanza("stream:stream", default_stream_attr):top_tag()); + + s2s_make_authenticated(session, session.to_host); + return true; +end) + +module:hook_stanza(xmlns_sasl, "failure", function (session, stanza) + if session.type ~= "s2sout_unauthed" or session.external_auth ~= "attempting" then return; end + + module:log("info", "SASL EXTERNAL with %s failed", session.to_host) + -- TODO: Log the failure reason + session.external_auth = "failed" +end, 500) + +module:hook_stanza(xmlns_sasl, "failure", function (session, stanza) + -- TODO: Dialback wasn't loaded. Do something useful. +end, 90) + +module:hook_stanza("http://etherx.jabber.org/streams", "features", function (session, stanza) + if session.type ~= "s2sout_unauthed" or not session.secure then return; end + + local mechanisms = stanza:get_child("mechanisms", xmlns_sasl) + if mechanisms then + for mech in mechanisms:childtags() do + if mech[1] == "EXTERNAL" then + module:log("debug", "Initiating SASL EXTERNAL with %s", session.to_host); + local reply = st.stanza("auth", {xmlns = xmlns_sasl, mechanism = "EXTERNAL"}); + reply:text(base64.encode(session.from_host)) + session.sends2s(reply) + session.external_auth = "attempting" + return true + end + end + end +end, 150); + +local function s2s_external_auth(session, stanza) + local mechanism = stanza.attr.mechanism; + + if not session.secure then + if mechanism == "EXTERNAL" then + session.sends2s(build_reply("failure", "encryption-required")) + else + session.sends2s(build_reply("failure", "invalid-mechanism")) + end + return true; + end + + if mechanism ~= "EXTERNAL" or session.cert_chain_status ~= "valid" then + session.sends2s(build_reply("failure", "invalid-mechanism")) + return true; + end + + local text = stanza[1] + if not text then + session.sends2s(build_reply("failure", "malformed-request")) + return true + end + + -- Either the value is "=" and we've already verified the external + -- cert identity, or the value is a string and either matches the + -- from_host ( + + text = base64.decode(text) + if not text then + session.sends2s(build_reply("failure", "incorrect-encoding")) + return true; + end + + if session.cert_identity_status == "valid" then + if text ~= "" and text ~= session.from_host then + session.sends2s(build_reply("failure", "invalid-authzid")) + return true + end + else + if text == "" then + session.sends2s(build_reply("failure", "invalid-authzid")) + return true + end + + local cert = session.conn:socket():getpeercertificate() + if (cert_verify_identity(text, "xmpp-server", cert)) then + session.cert_identity_status = "valid" + else + session.cert_identity_status = "invalid" + session.sends2s(build_reply("failure", "invalid-authzid")) + return true + end + end + + session.external_auth = "succeeded" + + if not session.from_host then + session.from_host = text; + end + session.sends2s(build_reply("success")) + module:log("info", "Accepting SASL EXTERNAL identity from %s", text or session.from_host); + s2s_make_authenticated(session, text or session.from_host) + session:reset_stream(); + return true +end + module:hook("stanza/urn:ietf:params:xml:ns:xmpp-sasl:auth", function(event) local session, stanza = event.origin, event.stanza; + if session.type == "s2sin_unauthed" then + return s2s_external_auth(session, stanza) + end + if session.type ~= "c2s_unauthed" then return; end if session.sasl_handler and session.sasl_handler.selected then @@ -168,6 +286,20 @@ module:hook("stream-features", function(event) end end); +module:hook("s2s-stream-features", function(event) + local origin, features = event.origin, event.features; + if origin.secure and origin.type == "s2sin_unauthed" then + -- Offer EXTERNAL if chain is valid and either we didn't validate + -- the identity or it passed. + if origin.cert_chain_status == "valid" and origin.cert_identity_status ~= "invalid" then --TODO: Configurable + module:log("debug", "Offering SASL EXTERNAL") + features:tag("mechanisms", { xmlns = xmlns_sasl }) + :tag("mechanism"):text("EXTERNAL") + :up():up(); + end + end +end); + module:hook("iq/self/urn:ietf:params:xml:ns:xmpp-bind:bind", function(event) local origin, stanza = event.origin, event.stanza; local resource; diff --git a/util/certverification.lua b/util/certverification.lua new file mode 100644 index 00000000..d323f4b4 --- /dev/null +++ b/util/certverification.lua @@ -0,0 +1,211 @@ +-- Prosody IM +-- Copyright (C) 2010 Matthew Wild +-- Copyright (C) 2010 Paul Aurich +-- +-- This project is MIT/X11 licensed. Please see the +-- COPYING file in the source package for more information. +-- + +-- TODO: I feel a fair amount of this logic should be integrated into Luasec, +-- so that everyone isn't re-inventing the wheel. Dependencies on +-- IDN libraries complicate that. + + +-- [TLS-CERTS] - http://tools.ietf.org/html/draft-saintandre-tls-server-id-check-10 +-- [XMPP-CORE] - http://tools.ietf.org/html/draft-ietf-xmpp-3920bis-18 +-- [SRV-ID] - http://tools.ietf.org/html/rfc4985 +-- [IDNA] - http://tools.ietf.org/html/rfc5890 +-- [LDAP] - http://tools.ietf.org/html/rfc4519 +-- [PKIX] - http://tools.ietf.org/html/rfc5280 + +local nameprep = require "util.encodings".stringprep.nameprep; +local idna_to_ascii = require "util.encodings".idna.to_ascii; +local log = require "util.logger".init("certverification"); + +module "certverification" + +local oid_commonname = "2.5.4.3"; -- [LDAP] 2.3 +local oid_subjectaltname = "2.5.29.17"; -- [PKIX] 4.2.1.6 +local oid_xmppaddr = "1.3.6.1.5.5.7.8.5"; -- [XMPP-CORE] +local oid_dnssrv = "1.3.6.1.5.5.7.8.7"; -- [SRV-ID] + +-- Compare a hostname (possibly international) with asserted names +-- extracted from a certificate. +-- This function follows the rules laid out in +-- sections 4.4.1 and 4.4.2 of [TLS-CERTS] +-- +-- A wildcard ("*") all by itself is allowed only as the left-most label +local function compare_dnsname(host, asserted_names) + -- TODO: Sufficient normalization? Review relevant specs. + local norm_host = idna_to_ascii(host) + if norm_host == nil then + log("info", "Host %s failed IDNA ToASCII operation", host) + return false + end + + norm_host = norm_host:lower() + + local host_chopped = norm_host:gsub("^[^.]+%.", "") -- everything after the first label + + for i=1,#asserted_names do + local name = asserted_names[i] + if norm_host == name:lower() then + log("debug", "Cert dNSName %s matched hostname", name); + return true + end + + -- Allow the left most label to be a "*" + if name:match("^%*%.") then + local rest_name = name:gsub("^[^.]+%.", "") + if host_chopped == rest_name:lower() then + log("debug", "Cert dNSName %s matched hostname", name); + return true + end + end + end + + return false +end + +-- Compare an XMPP domain name with the asserted id-on-xmppAddr +-- identities extracted from a certificate. Both are UTF8 strings. +-- +-- Per [XMPP-CORE], matches against asserted identities don't include +-- wildcards, so we just do a normalize on both and then a string comparison +-- +-- TODO: Support for full JIDs? +local function compare_xmppaddr(host, asserted_names) + local norm_host = nameprep(host) + + for i=1,#asserted_names do + local name = asserted_names[i] + + -- We only want to match against bare domains right now, not + -- those crazy full-er JIDs. + if name:match("[@/]") then + log("debug", "Ignoring xmppAddr %s because it's not a bare domain", name) + else + local norm_name = nameprep(name) + if norm_name == nil then + log("info", "Ignoring xmppAddr %s, failed nameprep!", name) + else + if norm_host == norm_name then + log("debug", "Cert xmppAddr %s matched hostname", name) + return true + end + end + end + end + + return false +end + +-- Compare a host + service against the asserted id-on-dnsSRV (SRV-ID) +-- identities extracted from a certificate. +-- +-- Per [SRV-ID], the asserted identities will be encoded in ASCII via ToASCII. +-- Comparison is done case-insensitively, and a wildcard ("*") all by itself +-- is allowed only as the left-most non-service label. +local function compare_srvname(host, service, asserted_names) + local norm_host = idna_to_ascii(host) + if norm_host == nil then + log("info", "Host %s failed IDNA ToASCII operation", host); + return false + end + + -- Service names start with a "_" + if service:match("^_") == nil then service = "_"..service end + + norm_host = norm_host:lower(); + local host_chopped = norm_host:gsub("^[^.]+%.", "") -- everything after the first label + + for i=1,#asserted_names do + local asserted_service, name = asserted_names[i]:match("^(_[^.]+)%.(.*)"); + if service == asserted_service then + if norm_host == name:lower() then + log("debug", "Cert SRVName %s matched hostname", name); + return true; + end + + -- Allow the left most label to be a "*" + if name:match("^%*%.") then + local rest_name = name:gsub("^[^.]+%.", "") + if host_chopped == rest_name:lower() then + log("debug", "Cert SRVName %s matched hostname", name) + return true + end + end + if norm_host == name:lower() then + log("debug", "Cert SRVName %s matched hostname", name); + return true + end + end + end + + return false +end + +function verify_identity(host, service, cert) + local ext = cert:extensions() + if ext[oid_subjectaltname] then + local sans = ext[oid_subjectaltname]; + + -- Per [TLS-CERTS] 4.3, 4.4.4, "a client MUST NOT seek a match for a + -- reference identifier if the presented identifiers include a DNS-ID + -- SRV-ID, URI-ID, or any application-specific identifier types" + local had_supported_altnames = false + + if sans[oid_xmppaddr] then + had_supported_altnames = true + if compare_xmppaddr(host, sans[oid_xmppaddr]) then return true end + end + + if sans[oid_dnssrv] then + had_supported_altnames = true + -- Only check srvNames if the caller specified a service + if service and compare_srvname(host, service, sans[oid_dnssrv]) then return true end + end + + if sans["dNSName"] then + had_supported_altnames = true + if compare_dnsname(host, sans["dNSName"]) then return true end + end + + -- We don't need URIs, but [TLS-CERTS] is clear. + if sans["uniformResourceIdentifier"] then + had_supported_altnames = true + end + + if had_supported_altnames then return false end + end + + -- Extract a common name from the certificate, and check it as if it were + -- a dNSName subjectAltName (wildcards may apply for, and receive, + -- cat treats) + -- + -- Per [TLS-CERTS] 1.5, a CN-ID is the Common Name from a cert subject + -- which has one and only one Common Name + local subject = cert:subject() + local cn = nil + for i=1,#subject do + local dn = subject[i] + if dn["oid"] == oid_commonname then + if cn then + log("info", "Certificate has multiple common names") + return false + end + + cn = dn["value"]; + end + end + + if cn then + -- Per [TLS-CERTS] 4.4.4, follow the comparison rules for dNSName SANs. + return compare_dnsname(host, { cn }) + end + + -- If all else fails, well, why should we be any different? + return false +end + +return _M; |