1 files changed, 11 insertions, 0 deletions
diff --git a/src/protosetup.c b/src/protosetup.c
index ad9ba88..bdc00c8 100644
--- a/src/protosetup.c
+++ b/src/protosetup.c
@@ -150,6 +150,17 @@ IceProtocolSetup (
 	SIZEOF (iceProtocolSetupMsg), WORD64COUNT (extra),
 	iceProtocolSetupMsg, pMsg, pData);
 
+    if (pData == NULL) {
+	iceConn->outbufptr -= SIZEOF (iceProtocolSetupMsg);
+	free(authIndices);
+	if (errorStringRet && errorLength > 0) {
+	    strncpy (errorStringRet,
+		"Too much extra data for iceProtocolSetupMsg", errorLength);
+	    errorStringRet[errorLength - 1] = '\0';
+	}
+	return (IceProtocolSetupFailure);
+    }
+
     setup_sequence = iceConn->send_sequence;
 
     pMsg->protocolOpcode = myOpcode;