[Qemu-devel] [PATCH v3 3/7] crypto: introduce new module for TLS x509 credentials

[Daniel P. Berrange]

Introduce a QCryptoTLSCredsX509 class which is used to
manage x509 certificate TLS credentials. This will be
the preferred credential type offering strong security
characteristics

Example CLI configuration:

 $QEMU -object tls-creds-x509,id=tls0,endpoint=server,\
               dir=/path/to/creds/dir,verify-peer=yes

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

 $QEMU -object tls-creds-x509,id=tls0,.... \
       -vnc 127.0.0.1:1,tls-creds=tls0

Signed-off-by: Daniel P. Berrange <address@hidden>
---
 crypto/Makefile.objs          |   1 +
 crypto/init.c                 |   2 +
 crypto/tlscredsx509.c         | 277 ++++++++++++++++++++++++++++++++++++++++++
 include/crypto/tlscredsx509.h | 114 +++++++++++++++++
 qemu-options.hx               |  27 ++++
 5 files changed, 421 insertions(+)
 create mode 100644 crypto/tlscredsx509.c
 create mode 100644 include/crypto/tlscredsx509.h

diff --git a/crypto/Makefile.objs b/crypto/Makefile.objs
index cf0199e..914bb68 100644
--- a/crypto/Makefile.objs
+++ b/crypto/Makefile.objs
@@ -5,3 +5,4 @@ util-obj-y += desrfb.o
 util-obj-y += cipher.o
 util-obj-y += tlscreds.o
 util-obj-y += tlscredsanon.o
+util-obj-y += tlscredsx509.o
diff --git a/crypto/init.c b/crypto/init.c
index bc4d769..a8b555a 100644
--- a/crypto/init.c
+++ b/crypto/init.c
@@ -20,6 +20,7 @@
 
 #include "crypto/init.h"
 #include "crypto/tlscredsanon.h"
+#include "crypto/tlscredsx509.h"
 #include "qemu/thread.h"
 
 #ifdef CONFIG_GNUTLS
@@ -144,6 +145,7 @@ int qcrypto_init(Error **errp)
      * clever enough to see the constructor :-(
      */
     qcrypto_tls_creds_anon_dummy();
+    qcrypto_tls_creds_x509_dummy();
 
     return 0;
 }
diff --git a/crypto/tlscredsx509.c b/crypto/tlscredsx509.c
new file mode 100644
index 0000000..0adb065
--- /dev/null
+++ b/crypto/tlscredsx509.c
@@ -0,0 +1,277 @@
+/*
+ * QEMU crypto TLS x509 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/>.
+ *
+ */
+
+#include "crypto/tlscredsx509.h"
+#include "crypto/tlscredspriv.h"
+#include "qom/object_interfaces.h"
+
+/* #define QCRYPTO_DEBUG */
+
+#ifdef QCRYPTO_DEBUG
+#define DPRINTF(fmt, ...) do { fprintf(stderr, fmt, ## __VA_ARGS__); } while 
(0)
+#else
+#define DPRINTF(fmt, ...) do { } while (0)
+#endif
+
+
+#ifdef CONFIG_GNUTLS
+
+
+static int
+qcrypto_tls_creds_x509_load(QCryptoTLSCredsX509 *creds,
+                            Error **errp)
+{
+    char *cacert = NULL, *cacrl = NULL, *cert = NULL,
+        *key = NULL, *dhparams = NULL;
+    int ret;
+    int rv = -1;
+
+    DPRINTF("Loading x509 creds %d from %s\n",
+            creds->type, creds->dir ? creds->dir : "<nodir>");
+
+    if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
+        if (qcrypto_tls_creds_get_path(&creds->parent_obj,
+                                       QCRYPTO_TLS_CREDS_X509_CA_CERT,
+                                       true, &cacert, errp) < 0 ||
+            qcrypto_tls_creds_get_path(&creds->parent_obj,
+                                       QCRYPTO_TLS_CREDS_X509_CA_CRL,
+                                       false, &cacrl, errp) < 0 ||
+            qcrypto_tls_creds_get_path(&creds->parent_obj,
+                                       QCRYPTO_TLS_CREDS_X509_SERVER_CERT,
+                                       true, &cert, errp) < 0 ||
+            qcrypto_tls_creds_get_path(&creds->parent_obj,
+                                       QCRYPTO_TLS_CREDS_X509_SERVER_KEY,
+                                       true, &key, errp) < 0 ||
+            qcrypto_tls_creds_get_path(&creds->parent_obj,
+                                       QCRYPTO_TLS_CREDS_DH_PARAMS,
+                                       false, &dhparams, errp) < 0) {
+            goto cleanup;
+        }
+    } else {
+        if (qcrypto_tls_creds_get_path(&creds->parent_obj,
+                                       QCRYPTO_TLS_CREDS_X509_CA_CERT,
+                                       true, &cacert, errp) < 0 ||
+            qcrypto_tls_creds_get_path(&creds->parent_obj,
+                                       QCRYPTO_TLS_CREDS_X509_CLIENT_CERT,
+                                       false, &cert, errp) < 0 ||
+            qcrypto_tls_creds_get_path(&creds->parent_obj,
+                                       QCRYPTO_TLS_CREDS_X509_CLIENT_KEY,
+                                       false, &key, errp) < 0) {
+            goto cleanup;
+        }
+    }
+
+    ret = gnutls_certificate_allocate_credentials(&creds->data);
+    if (ret < 0) {
+        error_setg(errp, "Cannot allocate credentials '%s'",
+                   gnutls_strerror(ret));
+        goto cleanup;
+    }
+
+    ret = gnutls_certificate_set_x509_trust_file(creds->data,
+                                                 cacert,
+                                                 GNUTLS_X509_FMT_PEM);
+    if (ret < 0) {
+        error_setg(errp, "Cannot load CA certificate '%s': %s",
+                   cacert, gnutls_strerror(ret));
+        goto cleanup;
+    }
+
+    if (cert != NULL && key != NULL) {
+        ret = gnutls_certificate_set_x509_key_file(creds->data,
+                                                   cert, key,
+                                                   GNUTLS_X509_FMT_PEM);
+        if (ret < 0) {
+            error_setg(errp, "Cannot load certificate '%s' & key '%s': %s",
+                       cert, key, gnutls_strerror(ret));
+            goto cleanup;
+        }
+    }
+
+    if (cacrl != NULL) {
+        ret = gnutls_certificate_set_x509_crl_file(creds->data,
+                                                   cacrl,
+                                                   GNUTLS_X509_FMT_PEM);
+        if (ret < 0) {
+            error_setg(errp, "Cannot load CRL '%s': %s",
+                       cacrl, gnutls_strerror(ret));
+            goto cleanup;
+        }
+    }
+
+    if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
+        if (qcrypto_tls_creds_get_dh_params_file(dhparams,
+                                                 &creds->parent_obj.dh_params,
+                                                 errp) < 0) {
+            goto cleanup;
+        }
+        gnutls_certificate_set_dh_params(creds->data,
+                                         creds->parent_obj.dh_params);
+    }
+
+    rv = 0;
+ cleanup:
+    g_free(cacert);
+    g_free(cacrl);
+    g_free(cert);
+    g_free(key);
+    g_free(dhparams);
+    return rv;
+}
+
+
+static void
+qcrypto_tls_creds_x509_unload(QCryptoTLSCredsX509 *creds)
+{
+    if (creds->data) {
+        gnutls_certificate_free_credentials(creds->data);
+        creds->data = NULL;
+    }
+}
+
+
+#else /* ! CONFIG_GNUTLS */
+
+
+static void
+qcrypto_tls_creds_x509_load(QCryptoTLSCredsX509 *creds G_GNUC_UNUSED,
+                            Error **errp)
+{
+    error_setg(errp, "TLS credentials support requires GNUTLS");
+}
+
+
+static void
+qcrypto_tls_creds_x509_unload(QCryptoTLSCredsX509 *creds G_GNUC_UNUSED)
+{
+    /* nada */
+}
+
+
+#endif /* ! CONFIG_GNUTLS */
+
+
+static void
+qcrypto_tls_creds_x509_prop_set_loaded(Object *obj,
+                                       bool value,
+                                       Error **errp)
+{
+    QCryptoTLSCredsX509 *creds = QCRYPTO_TLS_CREDS_X509(obj);
+
+    if (value) {
+        qcrypto_tls_creds_x509_load(creds, errp);
+    } else {
+        qcrypto_tls_creds_x509_unload(creds);
+    }
+}
+
+
+#ifdef CONFIG_GNUTLS
+
+
+static bool
+qcrypto_tls_creds_x509_prop_get_loaded(Object *obj,
+                                       Error **errp G_GNUC_UNUSED)
+{
+    QCryptoTLSCredsX509 *creds = QCRYPTO_TLS_CREDS_X509(obj);
+
+    return creds->data != NULL;
+}
+
+
+#else /* ! CONFIG_GNUTLS */
+
+
+static bool
+qcrypto_tls_creds_x509_prop_get_loaded(Object *obj G_GNUC_UNUSED,
+                                       Error **errp G_GNUC_UNUSED)
+{
+    return false;
+}
+
+
+#endif /* ! CONFIG_GNUTLS */
+
+
+static void
+qcrypto_tls_creds_x509_complete(UserCreatable *uc, Error **errp)
+{
+    object_property_set_bool(OBJECT(uc), true, "loaded", errp);
+}
+
+
+static void
+qcrypto_tls_creds_x509_init(Object *obj)
+{
+    object_property_add_bool(obj, "loaded",
+                             qcrypto_tls_creds_x509_prop_get_loaded,
+                             qcrypto_tls_creds_x509_prop_set_loaded,
+                             NULL);
+}
+
+
+static void
+qcrypto_tls_creds_x509_finalize(Object *obj)
+{
+    QCryptoTLSCredsX509 *creds = QCRYPTO_TLS_CREDS_X509(obj);
+
+    qcrypto_tls_creds_x509_unload(creds);
+}
+
+
+static void
+qcrypto_tls_creds_x509_class_init(ObjectClass *oc, void *data)
+{
+    UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
+
+    ucc->complete = qcrypto_tls_creds_x509_complete;
+}
+
+
+static const TypeInfo qcrypto_tls_creds_x509_info = {
+    .parent = TYPE_QCRYPTO_TLS_CREDS,
+    .name = TYPE_QCRYPTO_TLS_CREDS_X509,
+    .instance_size = sizeof(QCryptoTLSCredsX509),
+    .instance_init = qcrypto_tls_creds_x509_init,
+    .instance_finalize = qcrypto_tls_creds_x509_finalize,
+    .class_size = sizeof(QCryptoTLSCredsX509Class),
+    .class_init = qcrypto_tls_creds_x509_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_USER_CREATABLE },
+        { }
+    }
+};
+
+
+static void
+qcrypto_tls_creds_x509_register_types(void)
+{
+    DPRINTF("Register TLS x509\n");
+    type_register_static(&qcrypto_tls_creds_x509_info);
+}
+
+
+void
+qcrypto_tls_creds_x509_dummy(void)
+{
+}
+
+
+type_init(qcrypto_tls_creds_x509_register_types);
diff --git a/include/crypto/tlscredsx509.h b/include/crypto/tlscredsx509.h
new file mode 100644
index 0000000..bdb7b25
--- /dev/null
+++ b/include/crypto/tlscredsx509.h
@@ -0,0 +1,114 @@
+/*
+ * QEMU crypto TLS x509 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_X509_H__
+#define QCRYPTO_TLSCRED_X509_H__
+
+#include "crypto/tlscreds.h"
+
+#define TYPE_QCRYPTO_TLS_CREDS_X509 "tls-creds-x509"
+#define QCRYPTO_TLS_CREDS_X509(obj)                  \
+    OBJECT_CHECK(QCryptoTLSCredsX509, (obj), TYPE_QCRYPTO_TLS_CREDS_X509)
+
+typedef struct QCryptoTLSCredsX509 QCryptoTLSCredsX509;
+typedef struct QCryptoTLSCredsX509Class QCryptoTLSCredsX509Class;
+
+#define QCRYPTO_TLS_CREDS_X509_CA_CERT "ca-cert.pem"
+#define QCRYPTO_TLS_CREDS_X509_CA_CRL "ca-crl.pem"
+#define QCRYPTO_TLS_CREDS_X509_SERVER_KEY "server-key.pem"
+#define QCRYPTO_TLS_CREDS_X509_SERVER_CERT "server-cert.pem"
+#define QCRYPTO_TLS_CREDS_X509_CLIENT_KEY "client-key.pem"
+#define QCRYPTO_TLS_CREDS_X509_CLIENT_CERT "client-cert.pem"
+
+
+/**
+ * QCryptoTLSCredsX509:
+ *
+ * The QCryptoTLSCredsX509 object provides a representation
+ * of x509 credentials used to perform a TLS handshake.
+ *
+ * This is a user creatable object, which can be instantiated
+ * via object_new_propv():
+ *
+ * <example>
+ *   <title>Creating x509 TLS credential objects in code</title>
+ *   <programlisting>
+ *   Object *obj;
+ *   Error *err = NULL;
+ *   obj = object_new_propv(TYPE_QCRYPTO_TLS_CREDS_X509,
+ *                          "tlscreds0",
+ *                          &err,
+ *                          "endpoint", "server",
+ *                          "dir", "/path/x509/cert/dir",
+ *                          "verify-peer", "yes",
+ *                          NULL);
+ *   </programlisting>
+ * </example>
+ *
+ * Or via QMP:
+ *
+ * <example>
+ *   <title>Creating x509 TLS credential objects via QMP</title>
+ *   <programlisting>
+ *    {
+ *       "execute": "object-add", "arguments": {
+ *          "id": "tlscreds0",
+ *          "qom-type": "tls-creds-x509",
+ *          "props": {
+ *             "endpoint": "server",
+ *             "dir": "/path/to/x509/cert/dir",
+ *             "verify-peer": false
+ *          }
+ *       }
+ *    }
+ *   </programlisting>
+ * </example>
+ *
+ *
+ * Or via the CLI:
+ *
+ * <example>
+ *   <title>Creating x509 TLS credential objects via CLI</title>
+ *   <programlisting>
+ *  qemu-system-x86_64 -object tls-creds-x509,id=tlscreds0,\
+ *          endpoint=server,verify-peer=off,\
+ *          dir=/path/to/x509/certdir/
+ *   </programlisting>
+ * </example>
+ *
+ */
+
+struct QCryptoTLSCredsX509 {
+    QCryptoTLSCreds parent_obj;
+#ifdef CONFIG_GNUTLS
+    gnutls_certificate_credentials_t data;
+#endif
+};
+
+
+struct QCryptoTLSCredsX509Class {
+    QCryptoTLSCredsClass parent_class;
+};
+
+
+void qcrypto_tls_creds_x509_dummy(void);
+
+#endif /* QCRYPTO_TLSCRED_X509_H__ */
+
diff --git a/qemu-options.hx b/qemu-options.hx
index 057801a..23c91d5 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -3588,6 +3588,33 @@ expensive operation that consumes random pool entropy, 
so it is
 recommended that a persistent set of parameters be generated
 upfront and saved.
 
address@hidden -object 
tls-creds-x509,address@hidden,address@hidden,address@hidden/path/to/cred/dir},address@hidden|off}
+
+Creates a TLS anonymous credentials object, which can be used to provide
+TLS support on network backends. The @option{id} parameter is a unique
+ID which network backends will use to access the credentials. The
address@hidden is either @option{server} or @option{client} depending
+on whether the QEMU network backend that uses the credentials will be
+acting as a client or as a server. If @option{verify-peer} is enabled
+(the default) then once the handshake is completed, the peer credentials
+will be verified. With x509 certificates, this implies that the clients
+must be provided with valid client certificates too.
+
+The @var{dir} parameter tells QEMU where to find the credential
+files. For server endpoints, this directory may contain a file
address@hidden providing diffie-hellman parameters to use
+for the TLS server. If the file is missing, QEMU will generate
+a set of DH parameters at startup. This is a computationally
+expensive operation that consumes random pool entropy, so it is
+recommended that a persistent set of parameters be generated
+upfront and saved.
+
+For x509 certificate credentials the directory will contain further files
+providing the x509 certificates. The certificates must be stored
+in PEM format, in filenames @var{ca-cert.pem}, @var{ca-crl.pem} (optional),
address@hidden (only servers), @var{server-key.pem} (only servers),
address@hidden (only clients), and @var{client-key.pem} (only clients).
+
 @end table
 
 ETEXI
-- 
2.4.3