crypto: introduce new module for TLS anonymous credentials

Introduce a QCryptoTLSCredsAnon class which is used to
manage anonymous TLS credentials. Use of this class is
generally discouraged since it does not offer strong
security, but it is required for backwards compatibility
with the current VNC server implementation.

Simple example CLI configuration:

 $QEMU -object tls-creds-anon,id=tls0,endpoint=server

Example using pre-created diffie-hellman parameters

 $QEMU -object tls-creds-anon,id=tls0,endpoint=server,\
               dir=/path/to/creds/dir

The 'id' value in the -object args will be used to associate the
credentials with the network services. For example, when the VNC
server is later converted it would use

 $QEMU -object tls-creds-anon,id=tls0,.... \
       -vnc 127.0.0.1:1,tls-creds=tls0

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>

1 files changed, 112 insertions, 0 deletions

diff --git a/include/crypto/tlscredsanon.h b/include/crypto/tlscredsanon.h
new file mode 100644
index 0000000000..d3976b84b9
--- /dev/null
+++ b/include/crypto/tlscredsanon.h
@@ -0,0 +1,112 @@
+/*
+ * QEMU crypto TLS anonymous credential support
+ *
+ * Copyright (c) 2015 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef QCRYPTO_TLSCRED_ANON_H__
+#define QCRYPTO_TLSCRED_ANON_H__
+
+#include "crypto/tlscreds.h"
+
+#define TYPE_QCRYPTO_TLS_CREDS_ANON "tls-creds-anon"
+#define QCRYPTO_TLS_CREDS_ANON(obj)                  \
+    OBJECT_CHECK(QCryptoTLSCredsAnon, (obj), TYPE_QCRYPTO_TLS_CREDS_ANON)
+
+
+typedef struct QCryptoTLSCredsAnon QCryptoTLSCredsAnon;
+typedef struct QCryptoTLSCredsAnonClass QCryptoTLSCredsAnonClass;
+
+/**
+ * QCryptoTLSCredsAnon:
+ *
+ * The QCryptoTLSCredsAnon object provides a representation
+ * of anonymous credentials used perform a TLS handshake.
+ * This is primarily provided for backwards compatibility and
+ * its use is discouraged as it has poor security characteristics
+ * due to lacking MITM attack protection amongst other problems.
+ *
+ * This is a user creatable object, which can be instantiated
+ * via object_new_propv():
+ *
+ * <example>
+ *   <title>Creating anonymous TLS credential objects in code</title>
+ *   <programlisting>
+ *   Object *obj;
+ *   Error *err = NULL;
+ *   obj = object_new_propv(TYPE_QCRYPTO_TLS_CREDS_ANON,
+ *                          "tlscreds0",
+ *                          &err,
+ *                          "endpoint", "server",
+ *                          "dir", "/path/x509/cert/dir",
+ *                          "verify-peer", "yes",
+ *                          NULL);
+ *   </programlisting>
+ * </example>
+ *
+ * Or via QMP:
+ *
+ * <example>
+ *   <title>Creating anonymous TLS credential objects via QMP</title>
+ *   <programlisting>
+ *    {
+ *       "execute": "object-add", "arguments": {
+ *          "id": "tlscreds0",
+ *          "qom-type": "tls-creds-anon",
+ *          "props": {
+ *             "endpoint": "server",
+ *             "dir": "/path/to/x509/cert/dir",
+ *             "verify-peer": false
+ *          }
+ *       }
+ *    }
+ *   </programlisting>
+ * </example>
+ *
+ *
+ * Or via the CLI:
+ *
+ * <example>
+ *   <title>Creating anonymous TLS credential objects via CLI</title>
+ *   <programlisting>
+ *  qemu-system-x86_64 -object tls-creds-anon,id=tlscreds0,\
+ *          endpoint=server,verify-peer=off,\
+ *          dir=/path/to/x509/certdir/
+ *   </programlisting>
+ * </example>
+ *
+ */
+
+
+struct QCryptoTLSCredsAnon {
+    QCryptoTLSCreds parent_obj;
+#ifdef CONFIG_GNUTLS
+    union {
+        gnutls_anon_server_credentials_t server;
+        gnutls_anon_client_credentials_t client;
+    } data;
+#endif
+};
+
+
+struct QCryptoTLSCredsAnonClass {
+    QCryptoTLSCredsClass parent_class;
+};
+
+
+#endif /* QCRYPTO_TLSCRED_H__ */
+