* src/cyrsasl_digest.erl: Check digest-uri in SASL digest

authentication (thanks to Paul Guyot)(EJAB-569)

SVN Revision: 1743

1 files changed, 48 insertions, 22 deletions

diff --git a/src/cyrsasl_digest.erl b/src/cyrsasl_digest.erl
index 5395205d..0d27dbb6 100644
--- a/src/cyrsasl_digest.erl
+++ b/src/cyrsasl_digest.erl
@@ -18,7 +18,8 @@
 
 -behaviour(cyrsasl).
 
--record(state, {step, nonce, username, authzid, get_password, auth_module}).
+-record(state, {step, nonce, username, authzid, get_password, auth_module,
+		host}).
 
 start(_Opts) ->
     cyrsasl:register_mechanism("DIGEST-MD5", ?MODULE, true).
@@ -26,9 +27,10 @@ start(_Opts) ->
 stop() ->
     ok.
 
-mech_new(_Host, GetPassword, _CheckPassword) ->
+mech_new(Host, GetPassword, _CheckPassword) ->
     {ok, #state{step = 1,
 		nonce = randoms:get_string(),
+		host = Host,
 		get_password = GetPassword}}.
 
 mech_step(#state{step = 1, nonce = Nonce} = State, _) ->
@@ -41,27 +43,35 @@ mech_step(#state{step = 3, nonce = Nonce} = State, ClientIn) ->
 	bad ->
 	    {error, "bad-protocol"};
 	KeyVals ->
+	    DigestURI = xml:get_attr_s("digest-uri", KeyVals),
 	    UserName = xml:get_attr_s("username", KeyVals),
-	    AuthzId = xml:get_attr_s("authzid", KeyVals),
-	    case (State#state.get_password)(UserName) of
-		{false, _} ->
+	    case is_digesturi_valid(DigestURI, State#state.host) of
+		false ->
+		    ?DEBUG("User login not authorized because digest-uri "
+			   "seems invalid: ~p", [DigestURI]),
 		    {error, "not-authorized", UserName};
-		{Passwd, AuthModule} ->
-		    Response = response(KeyVals, UserName, Passwd,
-					Nonce, AuthzId, "AUTHENTICATE"),
-		    case xml:get_attr_s("response", KeyVals) of
-			Response ->
-			    RspAuth = response(KeyVals,
-					       UserName, Passwd,
-					       Nonce, AuthzId, ""),
-			    {continue,
-			     "rspauth=" ++ RspAuth,
-			     State#state{step = 5,
-					 auth_module = AuthModule,
-					 username = UserName,
-					 authzid = AuthzId}};
-			_ ->
-			    {error, "not-authorized", UserName}
+		true ->
+		    AuthzId = xml:get_attr_s("authzid", KeyVals),
+		    case (State#state.get_password)(UserName) of
+			{false, _} ->
+			    {error, "not-authorized", UserName};
+			{Passwd, AuthModule} ->
+			    Response = response(KeyVals, UserName, Passwd,
+						Nonce, AuthzId, "AUTHENTICATE"),
+			    case xml:get_attr_s("response", KeyVals) of
+				Response ->
+				    RspAuth = response(KeyVals,
+						       UserName, Passwd,
+						       Nonce, AuthzId, ""),
+				    {continue,
+				     "rspauth=" ++ RspAuth,
+				     State#state{step = 5,
+						 auth_module = AuthModule,
+						 username = UserName,
+						 authzid = AuthzId}};
+				_ ->
+				    {error, "not-authorized", UserName}
+			    end
 		    end
 	    end
     end;
@@ -75,7 +85,6 @@ mech_step(A, B) ->
     ?DEBUG("SASL DIGEST: A ~p B ~p", [A,B]),
     {error, "bad-protocol"}.
 
-
 parse(S) ->
     parse1(S, "", []).
 
@@ -118,6 +127,23 @@ parse4([], Key, Val, Ts) ->
     parse1([], "", [{Key, lists:reverse(Val)} | Ts]).
 
 
+%% @doc Check if the digest-uri is valid.
+%% RFC-2831 allows to provide the IP address in Host,
+%% however ejabberd doesn't allow that.
+%% If the service (for example jabber.example.org)
+%% is provided by several hosts (being one of them server3.example.org),
+%% then digest-uri can be like xmpp/server3.example.org/jabber.example.org
+%% In that case, ejabberd only checks the service name, not the host.
+is_digesturi_valid(DigestURICase, JabberHost) ->
+    DigestURI = stringprep:tolower(DigestURICase),
+    case catch string:tokens(DigestURI, "/") of
+	["xmpp", Host] when Host == JabberHost ->
+	    true;
+	["xmpp", _Host, ServName] when ServName == JabberHost ->
+	    true;
+	_ ->
+	    false
+    end.