Handle invalid handshake data properly in the core

Clients sending invalid handshake data could make the core crash
due to an unchecked pointer. This commit fixes this issue by having
the core close the socket if a peer could not be created.

Thanks to Bas Pape (Tucos) for finding this one!

diff --git a/src/common/peerfactory.cpp b/src/common/peerfactory.cpp
index 580c2ba..cd0987b 100644 (file)
--- a/src/common/peerfactory.cpp
+++ b/src/common/peerfactory.cpp
@@ -56,5 +56,5 @@ RemotePeer *PeerFactory::createPeer(const ProtoList &protocols, AuthHandler *aut
         }
     }
 
         }
     }
 

-    return 0;
+    return nullptr;

 }
 }

diff --git a/src/core/coreauthhandler.cpp b/src/core/coreauthhandler.cpp
index e380924..34fc222 100644 (file)
--- a/src/core/coreauthhandler.cpp
+++ b/src/core/coreauthhandler.cpp
@@ -81,7 +81,7 @@ void CoreAuthHandler::onReadyRead()
     }
 
     // read the list of protocols supported by the client
     }
 
     // read the list of protocols supported by the client

-    while (socket()->bytesAvailable() >= 4) {
+    while (socket()->bytesAvailable() >= 4 && _supportedProtos.size() < 16) { // sanity check

         quint32 data;
         socket()->read((char*)&data, 4);
         data = qFromBigEndian<quint32>(data);
         quint32 data;
         socket()->read((char*)&data, 4);
         data = qFromBigEndian<quint32>(data);


@@ -98,6 +98,12 @@ void CoreAuthHandler::onReadyRead()
                 level = Compressor::NoCompression;
 
             RemotePeer *peer = PeerFactory::createPeer(_supportedProtos, this, socket(), level, this);
                 level = Compressor::NoCompression;
 
             RemotePeer *peer = PeerFactory::createPeer(_supportedProtos, this, socket(), level, this);

+            if (!peer) {
+                qWarning() << "Received invalid handshake data from client" << socket()->peerAddress().toString();
+                close();
+                return;
+            }
+

             if (peer->protocol() == Protocol::LegacyProtocol) {
                 _legacy = true;
                 connect(peer, SIGNAL(protocolVersionMismatch(int,int)), SLOT(onProtocolVersionMismatch(int,int)));
             if (peer->protocol() == Protocol::LegacyProtocol) {
                 _legacy = true;
                 connect(peer, SIGNAL(protocolVersionMismatch(int,int)), SLOT(onProtocolVersionMismatch(int,int)));