migration: add support for encrypting data with TLS

This extends the migration_set_incoming_channel and
migration_set_outgoing_channel methods so that they
will automatically wrap the QIOChannel in a
QIOChannelTLS instance if TLS credentials are configured
in the migration parameters.

This allows TLS to work for tcp, unix, fd and exec
migration protocols. It does not (currently) work for
RDMA since it does not use these APIs, but it is
unlikely that TLS would be desired with RDMA anyway
since it would degrade the performance to that seen
with TCP defeating the purpose of using RDMA.

On the target host, QEMU would be launched with a set
of TLS credentials for a server endpoint

 $ qemu-system-x86_64 -monitor stdio -incoming defer \
    -object tls-creds-x509,dir=/home/berrange/security/qemutls,endpoint=server,id=tls0 \
    ...other args...

To enable incoming TLS migration 2 monitor commands are
then used

  (qemu) migrate_set_str_parameter tls-creds tls0
  (qemu) migrate_incoming tcp:myhostname:9000

On the source host, QEMU is launched in a similar
manner but using client endpoint credentials

 $ qemu-system-x86_64 -monitor stdio \
    -object tls-creds-x509,dir=/home/berrange/security/qemutls,endpoint=client,id=tls0 \
    ...other args...

To enable outgoing TLS migration 2 monitor commands are
then used

  (qemu) migrate_set_str_parameter tls-creds tls0
  (qemu) migrate tcp:otherhostname:9000

Thanks to earlier improvements to error reporting,
TLS errors can be seen 'info migrate' when doing a
detached migration. For example:

  (qemu) info migrate
  capabilities: xbzrle: off rdma-pin-all: off auto-converge: off zero-blocks: off compress: off events: off x-postcopy-ram: off
  Migration status: failed
  total time: 0 milliseconds
  error description: TLS handshake failed: The TLS connection was non-properly terminated.

Or

  (qemu) info migrate
  capabilities: xbzrle: off rdma-pin-all: off auto-converge: off zero-blocks: off compress: off events: off x-postcopy-ram: off
  Migration status: failed
  total time: 0 milliseconds
  error description: Certificate does not match the hostname localhost

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1461751518-12128-27-git-send-email-berrange@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>

1 files changed, 161 insertions, 0 deletions

diff --git a/migration/tls.c b/migration/tls.c
new file mode 100644
index 0000000000..75f959ff9c
--- /dev/null
+++ b/migration/tls.c
@@ -0,0 +1,161 @@
+/*
+ * QEMU migration TLS 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/>.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "migration/migration.h"
+#include "io/channel-tls.h"
+#include "crypto/tlscreds.h"
+#include "qemu/error-report.h"
+#include "qapi/error.h"
+#include "trace.h"
+
+static QCryptoTLSCreds *
+migration_tls_get_creds(MigrationState *s,
+                        QCryptoTLSCredsEndpoint endpoint,
+                        Error **errp)
+{
+    Object *creds;
+    QCryptoTLSCreds *ret;
+
+    creds = object_resolve_path_component(
+        object_get_objects_root(), s->parameters.tls_creds);
+    if (!creds) {
+        error_setg(errp, "No TLS credentials with id '%s'",
+                   s->parameters.tls_creds);
+        return NULL;
+    }
+    ret = (QCryptoTLSCreds *)object_dynamic_cast(
+        creds, TYPE_QCRYPTO_TLS_CREDS);
+    if (!ret) {
+        error_setg(errp, "Object with id '%s' is not TLS credentials",
+                   s->parameters.tls_creds);
+        return NULL;
+    }
+    if (ret->endpoint != endpoint) {
+        error_setg(errp,
+                   "Expected TLS credentials for a %s endpoint",
+                   endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT ?
+                   "client" : "server");
+        return NULL;
+    }
+
+    object_ref(OBJECT(ret));
+    return ret;
+}
+
+
+static void migration_tls_incoming_handshake(Object *src,
+                                             Error *err,
+                                             gpointer opaque)
+{
+    QIOChannel *ioc = QIO_CHANNEL(src);
+
+    if (err) {
+        trace_migration_tls_incoming_handshake_error(error_get_pretty(err));
+        error_report("%s", error_get_pretty(err));
+    } else {
+        trace_migration_tls_incoming_handshake_complete();
+        migration_set_incoming_channel(migrate_get_current(), ioc);
+    }
+    object_unref(OBJECT(ioc));
+}
+
+void migration_tls_set_incoming_channel(MigrationState *s,
+                                        QIOChannel *ioc,
+                                        Error **errp)
+{
+    QCryptoTLSCreds *creds;
+    QIOChannelTLS *tioc;
+
+    creds = migration_tls_get_creds(
+        s, QCRYPTO_TLS_CREDS_ENDPOINT_SERVER, errp);
+    if (!creds) {
+        return;
+    }
+
+    tioc = qio_channel_tls_new_server(
+        ioc, creds,
+        NULL, /* XXX pass ACL name */
+        errp);
+    if (!tioc) {
+        return;
+    }
+
+    trace_migration_tls_incoming_handshake_start();
+    qio_channel_tls_handshake(tioc,
+                              migration_tls_incoming_handshake,
+                              NULL,
+                              NULL);
+}
+
+
+static void migration_tls_outgoing_handshake(Object *src,
+                                             Error *err,
+                                             gpointer opaque)
+{
+    MigrationState *s = opaque;
+    QIOChannel *ioc = QIO_CHANNEL(src);
+
+    if (err) {
+        trace_migration_tls_outgoing_handshake_error(error_get_pretty(err));
+        s->to_dst_file = NULL;
+        migrate_fd_error(s, err);
+    } else {
+        trace_migration_tls_outgoing_handshake_complete();
+        migration_set_outgoing_channel(s, ioc, NULL);
+    }
+    object_unref(OBJECT(ioc));
+}
+
+
+void migration_tls_set_outgoing_channel(MigrationState *s,
+                                        QIOChannel *ioc,
+                                        const char *hostname,
+                                        Error **errp)
+{
+    QCryptoTLSCreds *creds;
+    QIOChannelTLS *tioc;
+
+    creds = migration_tls_get_creds(
+        s, QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT, errp);
+    if (!creds) {
+        return;
+    }
+
+    if (s->parameters.tls_hostname) {
+        hostname = s->parameters.tls_hostname;
+    }
+    if (!hostname) {
+        error_setg(errp, "No hostname available for TLS");
+        return;
+    }
+
+    tioc = qio_channel_tls_new_client(
+        ioc, creds, hostname, errp);
+    if (!tioc) {
+        return;
+    }
+
+    trace_migration_tls_outgoing_handshake_start(hostname);
+    qio_channel_tls_handshake(tioc,
+                              migration_tls_outgoing_handshake,
+                              s,
+                              NULL);
+}