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-rw-r--r--util/sasl/scram.lua79
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);