Fix checkNoWait logic in SSecurityPlain.

Currently it proceeds only if there aren't enough data in queue and then it blocks waiting.
Also the required amount to receive from network is (ulen + plen), not (ulen + plen + 2).

This allowed not authenticated clients to deny service to everyone.

diff --git a/common/rfb/SSecurityPlain.cxx b/common/rfb/SSecurityPlain.cxx
index f5a5cc7392a8555bde4c03e1f24bb804fe699165..05315490b9e15c77affbec041d27e43e3b5256df 100644 (file)
--- a/common/rfb/SSecurityPlain.cxx
+++ b/common/rfb/SSecurityPlain.cxx
@@ -92,7 +92,7 @@ bool SSecurityPlain::processMsg(SConnection* sc)
   }
 
   if (state == 1) {
-    if (is->checkNoWait(ulen + plen + 2))
+    if (!is->checkNoWait(ulen + plen))
       return false;
     state = 2;
     pw = new char[plen + 1];