Fail if username or password don't pass SASLprep.
[prosody.git] / util / sasl / scram.lua
index c3bc9600d465dddd6084e99d972c2898f726e8a4..f7b8300accf91cd273d47894e55955d1a36c6fb0 100644 (file)
 --    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 local s_match = string.match;
-
+local type = type
+local string = string
 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;
+local saslprep = require "util.encodings".stringprep.saslprep;
+local log = require "util.logger".init("sasl");
 
-module "plain"
+module "scram"
 
 --=========================
 --SASL SCRAM-SHA-1 according to draft-ietf-sasl-scram-10
@@ -34,7 +37,7 @@ local function bp( b )
 end
 
 local function binaryXOR( a, b )
-       if string.len(a) > string.len(b) then
+       if a:len() > b:len() then
                b = string.rep("\0", a:len() - b:len())..b
        elseif string.len(a) < string.len(b) then
                a = string.rep("\0", b:len() - a:len())..a
@@ -60,11 +63,18 @@ end
 
 local function validate_username(username)
        -- check for forbidden char sequences
-       for eq in s:gmatch("=(.?.?)") do
-               if eq ~= "2D" and eq ~= "3D" then return false end end return true;
+       for eq in username:gmatch("=(.?.?)") do
+               if eq ~= "2D" and eq ~= "3D" then
+                       return false 
+               end 
+       end
+       
        -- replace =2D with , and =3D with =
+       username:gsub("=2D", ",");
+       username:gsub("=3D", "=");
        
        -- apply SASLprep
+       username = saslprep(username);
        return username;
 end
 
@@ -74,19 +84,28 @@ local function scram_sha_1(self, message)
        if not self.state.name then
                -- we are processing client_first_message
                local client_first_message = message;
+               self.state["client_first_message"] = client_first_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 or not self.state.clientnonce then
                        return "failure", "malformed-request";
                end
+               
+               self.state.name = validate_username(self.state.name);
+               if not self.state.name then
+                       log("debug", "Username violates either SASLprep or contains forbidden character sequences.")
+                       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;
+               self.state["server_first_message"] = server_first_message;
                return "challenge", server_first_message
        else
+               if type(message) ~= "string" then return "failure", "malformed-request" end
                -- we are processing client_final_message
                local client_final_message = message;
                
@@ -102,19 +121,25 @@ local function scram_sha_1(self, message)
                        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
+                       password = saslprep(password);
+                       if not password then
+                               log("debug", "Password violates SASLprep.");
+                               return "failure", "not-authorized"
+                       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 AuthMessage = "n=" .. s_match(self.state.client_first_message,"n=(.+)") .. "," .. self.state.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);
+                       self["username"] = self.state.name;
                        return "success", server_final_message;
                else
                        return "failure", "not-authorized", "The response provided by the client doesn't match the one we calculated.";