Completed SCRAM-SHA-1 implementation to a ready-to-test state.

1 files changed, 41 insertions, 3 deletions

diff --git a/util/sasl/scram.lua b/util/sasl/scram.lua
index b7507f3e..9362cca7 100644
--- a/util/sasl/scram.lua
+++ b/util/sasl/scram.lua
@@ -17,6 +17,7 @@ local base64 = require "util.encodings".base64;
 local xor = require "bit".bxor
 local hmac_sha1 = require "util.hmac".sha1;
 local sha1 = require "util.hashes".sha1;
+local generate_uuid = require "util.uuid".generate;
 
 module "plain"
 
@@ -71,15 +72,52 @@ local function scram_sha_1(self, message)
 	
 	if not self.state.name then
 		-- we are processing client_first_message
-		self.state["name"] = string.match(client_first_message, "n=(.+),r=")
-		self.state["clientnonce"] = string.match(client_first_message, "r=([^,]+)")
+		local client_first_message = message;
+		self.state["name"] = client_first_message:match("n=(.+),r=")
+		self.state["clientnonce"] = client_first_message:match("r=([^,]+)")
 		
 		self.state.name = validate_username(self.state.name);
-		if not self.state.name then
+		if not self.state.name or not self.state.clientnonce then
 			return "failure", "malformed-request";
 		end
+		self.state["servernonce"] = generate_uuid();
+		self.state["salt"] = generate_uuid();
+		
+		local server_first_message = "r="..self.state.clientnonce..self.state.servernonce..",s="..base64.encode(self.state.salt)..",i="..default_i;
+		return "challenge", server_first_message
 	else
 		-- we are processing client_final_message
+		local client_final_message = message;
+		
+		self.state["proof"] = client_final_message:match("p=(.+)");
+		self.state["nonce"] = client_final_message:match("r=(.+),p=");
+		self.state["channelbinding"] = client_final_message:match("c=(.+),r=");
+		if not self.state.proof or not self.state.nonce or not self.state.channelbinding then
+			return "failure", "malformed-request";
+		end
+		
+		local password;
+		if self.profile.plain then
+			password, state = self.profile.plain(self.state.name, self.realm)
+			if state == nil then return "failure", "not-authorized"
+			elseif state == false then return "failure", "account-disabled" end
+		end
+		
+		local SaltedPassword = Hi(hmac_sha1, password, self.state.salt, default_i)
+		local ClientKey = hmac_sha1(SaltedPassword, "Client Key")
+		local ServerKey = hmac_sha1(SaltedPassword, "Server Key")
+		local StoredKey = sha1(ClientKey)
+		local AuthMessage = "n=" .. s_match(client_first_message,"n=(.+)") .. "," .. server_first_message .. "," .. s_match(client_final_message, "(.+),p=.+")
+		local ClientSignature = hmac_sha1(StoredKey, AuthMessage)
+		local ClientProof     = binaryXOR(ClientKey, ClientSignature)
+		local ServerSignature = hmac_sha1(ServerKey, AuthMessage)
+		
+		if base64.encode(ClientProof) == self.state.proof then
+			local server_final_message = "v="..base64.encode(ServerSignature);
+			return "success", server_final_message;
+		else
+			return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";
+		end
 	end
 end