crypto: Implement TLS Pre-Shared Keys (PSK).

Pre-Shared Keys (PSK) is a simpler mechanism for enabling TLS
connections than using certificates.  It requires only a simple secret
key:

  $ mkdir -m 0700 /tmp/keys
  $ psktool -u rjones -p /tmp/keys/keys.psk
  $ cat /tmp/keys/keys.psk
  rjones:d543770c15ad93d76443fb56f501a31969235f47e999720ae8d2336f6a13fcbc

The key can be secretly shared between clients and servers.  Clients
must specify the directory containing the "keys.psk" file and a
username (defaults to "qemu").  Servers must specify only the
directory.

Example NBD client:

  $ qemu-img info \
    --object tls-creds-psk,id=tls0,dir=/tmp/keys,username=rjones,endpoint=client \
    --image-opts \
    file.driver=nbd,file.host=localhost,file.port=10809,file.tls-creds=tls0,file.export=/

Example NBD server using qemu-nbd:

  $ qemu-nbd -t -x / \
    --object tls-creds-psk,id=tls0,endpoint=server,dir=/tmp/keys \
    --tls-creds tls0 \
    image.qcow2

Example NBD server using nbdkit:

  $ nbdkit -n -e / -fv \
    --tls=on --tls-psk=/tmp/keys/keys.psk \
    file file=disk.img

Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

1 files changed, 50 insertions, 0 deletions

diff --git a/tests/crypto-tls-psk-helpers.c b/tests/crypto-tls-psk-helpers.c
new file mode 100644
index 0000000..a839547
--- /dev/null
+++ b/tests/crypto-tls-psk-helpers.c
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2015-2018 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 2.1 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/>.
+ *
+ * Author: Richard W.M. Jones <rjones@redhat.com>
+ */
+
+#include "qemu/osdep.h"
+
+/* Include this first because it defines QCRYPTO_HAVE_TLS_TEST_SUPPORT */
+#include "crypto-tls-x509-helpers.h"
+
+#include "crypto-tls-psk-helpers.h"
+#include "qemu/sockets.h"
+
+#ifdef QCRYPTO_HAVE_TLS_TEST_SUPPORT
+
+void test_tls_psk_init(const char *pskfile)
+{
+    FILE *fp;
+
+    fp = fopen(pskfile, "w");
+    if (fp == NULL) {
+        g_critical("Failed to create pskfile %s", pskfile);
+        abort();
+    }
+    /* Don't do this in real applications!  Use psktool. */
+    fprintf(fp, "qemu:009d5638c40fde0c\n");
+    fclose(fp);
+}
+
+void test_tls_psk_cleanup(const char *pskfile)
+{
+    unlink(pskfile);
+}
+
+#endif /* QCRYPTO_HAVE_TLS_TEST_SUPPORT */