io: add QIOChannelTLS class

Add a QIOChannel subclass that can run the TLS protocol over
the top of another QIOChannel instance. The object provides a
simplified API to perform the handshake when starting the TLS
session. The layering of TLS over the underlying channel does
not have to be setup immediately. It is possible to take an
existing QIOChannel that has done some handshake and then swap
in the QIOChannelTLS layer. This allows for use with protocols
which start TLS right away, and those which start plain text
and then negotiate TLS.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

2 files changed, 394 insertions, 0 deletions

diff --git a/io/Makefile.objs b/io/Makefile.objs
index 3d2f232480..a48011b726 100644
--- a/io/Makefile.objs
+++ b/io/Makefile.objs
@@ -1,5 +1,6 @@
 io-obj-y = channel.o
 io-obj-y += channel-file.o
 io-obj-y += channel-socket.o
+io-obj-y += channel-tls.o
 io-obj-y += channel-watch.o
 io-obj-y += task.o
diff --git a/io/channel-tls.c b/io/channel-tls.c
new file mode 100644
index 0000000000..8ac4f76f78
--- /dev/null
+++ b/io/channel-tls.c
@@ -0,0 +1,393 @@
+/*
+ * QEMU I/O channels TLS driver
+ *
+ * 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 "io/channel-tls.h"
+#include "trace.h"
+
+
+static ssize_t qio_channel_tls_write_handler(const char *buf,
+                                             size_t len,
+                                             void *opaque)
+{
+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(opaque);
+    ssize_t ret;
+
+    ret = qio_channel_write(tioc->master, buf, len, NULL);
+    if (ret == QIO_CHANNEL_ERR_BLOCK) {
+        errno = EAGAIN;
+        return -1;
+    } else if (ret < 0) {
+        errno = EIO;
+        return -1;
+    }
+    return ret;
+}
+
+static ssize_t qio_channel_tls_read_handler(char *buf,
+                                            size_t len,
+                                            void *opaque)
+{
+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(opaque);
+    ssize_t ret;
+
+    ret = qio_channel_read(tioc->master, buf, len, NULL);
+    if (ret == QIO_CHANNEL_ERR_BLOCK) {
+        errno = EAGAIN;
+        return -1;
+    } else if (ret < 0) {
+        errno = EIO;
+        return -1;
+    }
+    return ret;
+}
+
+
+QIOChannelTLS *
+qio_channel_tls_new_server(QIOChannel *master,
+                           QCryptoTLSCreds *creds,
+                           const char *aclname,
+                           Error **errp)
+{
+    QIOChannelTLS *ioc;
+
+    ioc = QIO_CHANNEL_TLS(object_new(TYPE_QIO_CHANNEL_TLS));
+
+    ioc->master = master;
+    object_ref(OBJECT(master));
+
+    ioc->session = qcrypto_tls_session_new(
+        creds,
+        NULL,
+        aclname,
+        QCRYPTO_TLS_CREDS_ENDPOINT_SERVER,
+        errp);
+    if (!ioc->session) {
+        goto error;
+    }
+
+    qcrypto_tls_session_set_callbacks(
+        ioc->session,
+        qio_channel_tls_write_handler,
+        qio_channel_tls_read_handler,
+        ioc);
+
+    trace_qio_channel_tls_new_server(ioc, master, creds, aclname);
+    return ioc;
+
+ error:
+    object_unref(OBJECT(ioc));
+    return NULL;
+}
+
+QIOChannelTLS *
+qio_channel_tls_new_client(QIOChannel *master,
+                           QCryptoTLSCreds *creds,
+                           const char *hostname,
+                           Error **errp)
+{
+    QIOChannelTLS *tioc;
+    QIOChannel *ioc;
+
+    tioc = QIO_CHANNEL_TLS(object_new(TYPE_QIO_CHANNEL_TLS));
+    ioc = QIO_CHANNEL(tioc);
+
+    tioc->master = master;
+    if (master->features & (1 << QIO_CHANNEL_FEATURE_SHUTDOWN)) {
+        ioc->features |= (1 << QIO_CHANNEL_FEATURE_SHUTDOWN);
+    }
+    object_ref(OBJECT(master));
+
+    tioc->session = qcrypto_tls_session_new(
+        creds,
+        hostname,
+        NULL,
+        QCRYPTO_TLS_CREDS_ENDPOINT_CLIENT,
+        errp);
+    if (!tioc->session) {
+        goto error;
+    }
+
+    qcrypto_tls_session_set_callbacks(
+        tioc->session,
+        qio_channel_tls_write_handler,
+        qio_channel_tls_read_handler,
+        tioc);
+
+    trace_qio_channel_tls_new_client(tioc, master, creds, hostname);
+    return tioc;
+
+ error:
+    object_unref(OBJECT(tioc));
+    return NULL;
+}
+
+
+static gboolean qio_channel_tls_handshake_io(QIOChannel *ioc,
+                                             GIOCondition condition,
+                                             gpointer user_data);
+
+static void qio_channel_tls_handshake_task(QIOChannelTLS *ioc,
+                                           QIOTask *task)
+{
+    Error *err = NULL;
+    QCryptoTLSSessionHandshakeStatus status;
+
+    if (qcrypto_tls_session_handshake(ioc->session, &err) < 0) {
+        trace_qio_channel_tls_handshake_fail(ioc);
+        qio_task_abort(task, err);
+        goto cleanup;
+    }
+
+    status = qcrypto_tls_session_get_handshake_status(ioc->session);
+    if (status == QCRYPTO_TLS_HANDSHAKE_COMPLETE) {
+        trace_qio_channel_tls_handshake_complete(ioc);
+        if (qcrypto_tls_session_check_credentials(ioc->session,
+                                                  &err) < 0) {
+            trace_qio_channel_tls_credentials_deny(ioc);
+            qio_task_abort(task, err);
+            goto cleanup;
+        }
+        trace_qio_channel_tls_credentials_allow(ioc);
+        qio_task_complete(task);
+    } else {
+        GIOCondition condition;
+        if (status == QCRYPTO_TLS_HANDSHAKE_SENDING) {
+            condition = G_IO_OUT;
+        } else {
+            condition = G_IO_IN;
+        }
+
+        trace_qio_channel_tls_handshake_pending(ioc, status);
+        qio_channel_add_watch(ioc->master,
+                              condition,
+                              qio_channel_tls_handshake_io,
+                              task,
+                              NULL);
+    }
+
+ cleanup:
+    error_free(err);
+}
+
+
+static gboolean qio_channel_tls_handshake_io(QIOChannel *ioc,
+                                             GIOCondition condition,
+                                             gpointer user_data)
+{
+    QIOTask *task = user_data;
+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(
+        qio_task_get_source(task));
+
+    qio_channel_tls_handshake_task(
+       tioc, task);
+
+    object_unref(OBJECT(tioc));
+
+    return FALSE;
+}
+
+void qio_channel_tls_handshake(QIOChannelTLS *ioc,
+                               QIOTaskFunc func,
+                               gpointer opaque,
+                               GDestroyNotify destroy)
+{
+    QIOTask *task;
+
+    task = qio_task_new(OBJECT(ioc),
+                        func, opaque, destroy);
+
+    trace_qio_channel_tls_handshake_start(ioc);
+    qio_channel_tls_handshake_task(ioc, task);
+}
+
+
+static void qio_channel_tls_init(Object *obj G_GNUC_UNUSED)
+{
+}
+
+
+static void qio_channel_tls_finalize(Object *obj)
+{
+    QIOChannelTLS *ioc = QIO_CHANNEL_TLS(obj);
+
+    object_unref(OBJECT(ioc->master));
+    qcrypto_tls_session_free(ioc->session);
+}
+
+
+static ssize_t qio_channel_tls_readv(QIOChannel *ioc,
+                                     const struct iovec *iov,
+                                     size_t niov,
+                                     int **fds,
+                                     size_t *nfds,
+                                     Error **errp)
+{
+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc);
+    size_t i;
+    ssize_t got = 0;
+
+    for (i = 0 ; i < niov ; i++) {
+        ssize_t ret = qcrypto_tls_session_read(tioc->session,
+                                               iov[i].iov_base,
+                                               iov[i].iov_len);
+        if (ret < 0) {
+            if (errno == EAGAIN) {
+                if (got) {
+                    return got;
+                } else {
+                    return QIO_CHANNEL_ERR_BLOCK;
+                }
+            }
+
+            error_setg_errno(errp, errno,
+                             "Cannot read from TLS channel");
+            return -1;
+        }
+        got += ret;
+        if (ret < iov[i].iov_len) {
+            break;
+        }
+    }
+    return got;
+}
+
+
+static ssize_t qio_channel_tls_writev(QIOChannel *ioc,
+                                      const struct iovec *iov,
+                                      size_t niov,
+                                      int *fds,
+                                      size_t nfds,
+                                      Error **errp)
+{
+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc);
+    size_t i;
+    ssize_t done = 0;
+
+    for (i = 0 ; i < niov ; i++) {
+        ssize_t ret = qcrypto_tls_session_write(tioc->session,
+                                                iov[i].iov_base,
+                                                iov[i].iov_len);
+        if (ret <= 0) {
+            if (errno == EAGAIN) {
+                if (done) {
+                    return done;
+                } else {
+                    return QIO_CHANNEL_ERR_BLOCK;
+                }
+            }
+
+            error_setg_errno(errp, errno,
+                             "Cannot write to TLS channel");
+            return -1;
+        }
+        done += ret;
+        if (ret < iov[i].iov_len) {
+            break;
+        }
+    }
+    return done;
+}
+
+static int qio_channel_tls_set_blocking(QIOChannel *ioc,
+                                        bool enabled,
+                                        Error **errp)
+{
+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc);
+
+    return qio_channel_set_blocking(tioc->master, enabled, errp);
+}
+
+static void qio_channel_tls_set_delay(QIOChannel *ioc,
+                                      bool enabled)
+{
+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc);
+
+    qio_channel_set_delay(tioc->master, enabled);
+}
+
+static void qio_channel_tls_set_cork(QIOChannel *ioc,
+                                     bool enabled)
+{
+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc);
+
+    qio_channel_set_cork(tioc->master, enabled);
+}
+
+static int qio_channel_tls_shutdown(QIOChannel *ioc,
+                                    QIOChannelShutdown how,
+                                    Error **errp)
+{
+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc);
+
+    return qio_channel_shutdown(tioc->master, how, errp);
+}
+
+static int qio_channel_tls_close(QIOChannel *ioc,
+                                 Error **errp)
+{
+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc);
+
+    return qio_channel_close(tioc->master, errp);
+}
+
+static GSource *qio_channel_tls_create_watch(QIOChannel *ioc,
+                                             GIOCondition condition)
+{
+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc);
+
+    return qio_channel_create_watch(tioc->master, condition);
+}
+
+QCryptoTLSSession *
+qio_channel_tls_get_session(QIOChannelTLS *ioc)
+{
+    return ioc->session;
+}
+
+static void qio_channel_tls_class_init(ObjectClass *klass,
+                                       void *class_data G_GNUC_UNUSED)
+{
+    QIOChannelClass *ioc_klass = QIO_CHANNEL_CLASS(klass);
+
+    ioc_klass->io_writev = qio_channel_tls_writev;
+    ioc_klass->io_readv = qio_channel_tls_readv;
+    ioc_klass->io_set_blocking = qio_channel_tls_set_blocking;
+    ioc_klass->io_set_delay = qio_channel_tls_set_delay;
+    ioc_klass->io_set_cork = qio_channel_tls_set_cork;
+    ioc_klass->io_close = qio_channel_tls_close;
+    ioc_klass->io_shutdown = qio_channel_tls_shutdown;
+    ioc_klass->io_create_watch = qio_channel_tls_create_watch;
+}
+
+static const TypeInfo qio_channel_tls_info = {
+    .parent = TYPE_QIO_CHANNEL,
+    .name = TYPE_QIO_CHANNEL_TLS,
+    .instance_size = sizeof(QIOChannelTLS),
+    .instance_init = qio_channel_tls_init,
+    .instance_finalize = qio_channel_tls_finalize,
+    .class_init = qio_channel_tls_class_init,
+};
+
+static void qio_channel_tls_register_types(void)
+{
+    type_register_static(&qio_channel_tls_info);
+}
+
+type_init(qio_channel_tls_register_types);