[libvirt] [PATCH v1 11/23] locking: Introduce virSeclabelSpace
Michal Privoznik
mprivozn at redhat.com
Mon Oct 12 10:25:56 UTC 2015
This module will handle all the security label remembering and
recalling for virlockd. We need to record a tuple of (path,
security model, security label). So I'm going with a hash table,
where @path would be the key, and tuple of (model, label) is
going to be the payload. Well, the payload tuple is wrapped into
self inflating array (virSeclabelSpaceLabels). So for each path,
we will have to traverse through array of various models to find
the needed one. But since there's gonna be many paths and just a
few security models, it's going to be the best approach.
Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
po/POTFILES.in | 1 +
src/Makefile.am | 2 +
src/locking/lock_daemon_seclabels.c | 545 ++++++++++++++++++++++++++++++++++++
src/locking/lock_daemon_seclabels.h | 43 +++
4 files changed, 591 insertions(+)
create mode 100644 src/locking/lock_daemon_seclabels.c
create mode 100644 src/locking/lock_daemon_seclabels.h
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 0cc5b99..04dbad3 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -74,6 +74,7 @@ src/libvirt-qemu.c
src/locking/lock_daemon.c
src/locking/lock_daemon_config.c
src/locking/lock_daemon_dispatch.c
+src/locking/lock_daemon_seclabels.c
src/locking/lock_driver_lockd.c
src/locking/lock_driver_sanlock.c
src/locking/lock_manager.c
diff --git a/src/Makefile.am b/src/Makefile.am
index d5dd9fb..e706166 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -253,6 +253,8 @@ LOCK_DAEMON_SOURCES = \
locking/lock_daemon_config.c \
locking/lock_daemon_dispatch.c \
locking/lock_daemon_dispatch.h \
+ locking/lock_daemon_seclabels.c \
+ locking/lock_daemon_seclabels.h \
$(NULL)
locking/lock_daemon_dispatch_stubs.h: $(LOCK_PROTOCOL) \
diff --git a/src/locking/lock_daemon_seclabels.c b/src/locking/lock_daemon_seclabels.c
new file mode 100644
index 0000000..8c3e4a0
--- /dev/null
+++ b/src/locking/lock_daemon_seclabels.c
@@ -0,0 +1,545 @@
+/*
+ * lock_daemon_seclabels.c: Security label mgmt
+ *
+ * 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 2.1 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: Michal Privoznik <mprivozn at redhat.com>
+ */
+
+#include <config.h>
+
+#include "viralloc.h"
+#include "virerror.h"
+#include "virhash.h"
+#include "virjson.h"
+#include "virlog.h"
+#include "virstring.h"
+
+#define VIR_FROM_THIS VIR_FROM_RPC
+
+VIR_LOG_INIT("locking.lock_daemon_dispatch");
+
+#include "lock_daemon.h"
+#include "lock_daemon_seclabels.h"
+
+typedef struct _virSeclabel virSeclabel;
+typedef virSeclabel *virSeclabelPtr;
+
+struct _virSeclabel {
+ char *model;
+ char *label;
+ unsigned int refcount;
+};
+
+
+typedef struct _virSeclabelSpaceLabels virSeclabelSpaceLabels;
+typedef virSeclabelSpaceLabels *virSeclabelSpaceLabelsPtr;
+
+struct _virSeclabelSpaceLabels {
+ virSeclabelPtr *labels;
+ size_t nlabels;
+};
+
+struct _virSeclabelSpace {
+ virMutex lock;
+
+ virHashTablePtr labels;
+};
+
+
+static void
+virSeclabelFree(virSeclabelPtr label)
+{
+ if (!label)
+ return;
+
+ VIR_FREE(label->model);
+ VIR_FREE(label->label);
+ VIR_FREE(label);
+}
+
+
+static virSeclabelPtr
+virSeclabelNew(const char *model,
+ const char *label)
+{
+ virSeclabelPtr ret;
+
+ if (VIR_ALLOC(ret) < 0)
+ return NULL;
+
+ if (VIR_STRDUP(ret->model, model) < 0 ||
+ VIR_STRDUP(ret->label, label) < 0)
+ goto error;
+
+ ret->refcount = 1;
+
+ return ret;
+ error:
+ virSeclabelFree(ret);
+ return NULL;
+}
+
+
+static void
+virSeclabelSpaceLabelsFree(virSeclabelSpaceLabelsPtr labels)
+{
+ size_t i;
+
+ if (!labels)
+ return;
+
+ for (i = 0; i < labels->nlabels; i++)
+ virSeclabelFree(labels->labels[i]);
+
+ VIR_FREE(labels->labels);
+ VIR_FREE(labels);
+}
+
+static void
+virSeclabelSpaceLabelsHashFree(void *payload,
+ const void *name ATTRIBUTE_UNUSED)
+{
+ virSeclabelSpaceLabelsFree(payload);
+}
+
+
+static void
+virSeclabelSpaceLock(virSeclabelSpacePtr space)
+{
+ virMutexLock(&space->lock);
+}
+
+
+static void
+virSeclabelSpaceUnlock(virSeclabelSpacePtr space)
+{
+ virMutexUnlock(&space->lock);
+}
+
+
+void
+virSeclabelSpaceFree(virSeclabelSpacePtr space)
+{
+ if (!space)
+ return;
+
+ virMutexDestroy(&space->lock);
+ virHashFree(space->labels);
+ VIR_FREE(space);
+}
+
+
+virSeclabelSpacePtr
+virSeclabelSpaceNew(void)
+{
+ virSeclabelSpacePtr ret;
+
+ if (VIR_ALLOC(ret) < 0)
+ return NULL;
+
+ if (virMutexInit(&ret->lock) < 0) {
+ virReportSystemError(errno, "%s",
+ _("Unable to init mutex"));
+ goto error;
+ }
+
+ if (!(ret->labels = virHashCreate(10, virSeclabelSpaceLabelsHashFree)))
+ goto error;
+
+ return ret;
+ error:
+ virSeclabelSpaceFree(ret);
+ return NULL;
+}
+
+
+static virSeclabelPtr
+virSeclabelSpaceLookup(virSeclabelSpacePtr space,
+ const char *path,
+ const char *model)
+{
+ virSeclabelSpaceLabelsPtr labels;
+ virSeclabelPtr ret;
+ size_t i;
+
+ if (!(labels = virHashLookup(space->labels, path)))
+ return NULL;
+
+ for (i = 0; labels->nlabels; i++) {
+ ret = labels->labels[i];
+
+ if (STREQ(ret->model, model))
+ return ret;
+ }
+
+ return NULL;
+}
+
+
+static int
+virSeclabelSpaceAdd(virSeclabelSpacePtr space,
+ const char *path,
+ virSeclabelPtr label)
+{
+ virSeclabelSpaceLabelsPtr labels;
+ virSeclabelPtr tmp;
+ size_t i;
+ int ret = -1;
+
+ if (!(labels = virHashLookup(space->labels, path))) {
+ /* Add new */
+ if (VIR_ALLOC(labels) < 0 ||
+ VIR_ALLOC(labels->labels) < 0 ||
+ virHashAddEntry(space->labels, path, labels) < 0) {
+ virSeclabelSpaceLabelsFree(labels);
+ goto cleanup;
+ }
+
+ labels->labels[0] = label;
+ labels->nlabels = 1;
+ } else {
+ /* Update old */
+ for (i = 0; i < labels->nlabels; i++) {
+ tmp = labels->labels[i];
+
+ if (STREQ(tmp->model, label->model)) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("duplicate label for model '%s': old: '%s' new '%s'"),
+ tmp->model, tmp->label, label->label);
+ goto cleanup;
+ }
+ }
+
+ if (VIR_APPEND_ELEMENT_COPY(labels->labels, labels->nlabels, label) < 0)
+ goto cleanup;
+
+ if (virHashUpdateEntry(space->labels, path, labels) < 0)
+ goto cleanup;
+ }
+
+ ret = 0;
+ cleanup:
+ return ret;
+}
+
+
+static void
+virSeclabelSpaceRemove(virSeclabelSpacePtr space,
+ const char *path,
+ virSeclabelPtr seclabel)
+{
+ virSeclabelSpaceLabelsPtr labels;
+ virSeclabelPtr tmp;
+ size_t i;
+
+ if (!(labels = virHashLookup(space->labels, path))) {
+ /* path not found */
+ return;
+ }
+
+ for (i = 0; i < labels->nlabels; i++) {
+ tmp = labels->labels[i];
+
+ if (STREQ(seclabel->model, tmp->model))
+ break;
+ }
+
+ if (i == labels->nlabels) {
+ /* model not found */
+ return;
+ }
+
+ tmp = labels->labels[i];
+
+ VIR_DELETE_ELEMENT(labels->labels, i, labels->nlabels);
+
+ if (!labels->nlabels)
+ virHashRemoveEntry(space->labels, path);
+}
+
+
+struct virSeclabelSpaceIteratorData {
+ virJSONValuePtr labels;
+ bool error;
+};
+
+
+static void
+virSeclabelSpaceIterator(void *payload,
+ const void *name,
+ void *opaque)
+{
+ virSeclabelSpaceLabelsPtr labels = payload;
+ const char *path = name;
+ struct virSeclabelSpaceIteratorData *data = opaque;
+ virSeclabelPtr tmp;
+ virJSONValuePtr item, jsonLabels, jsonLabel;
+ size_t i;
+
+ if (data->error)
+ return;
+
+ if (!(item = virJSONValueNewObject()))
+ goto error;
+
+ if (virJSONValueObjectAppendString(item, "path", path) < 0)
+ goto error;
+
+ if (!(jsonLabels = virJSONValueNewArray()))
+ goto error;
+
+ for (i = 0; i < labels->nlabels; i++) {
+ tmp = labels->labels[i];
+
+ if (!(jsonLabel = virJSONValueNewObject()))
+ goto error;
+
+ if (virJSONValueObjectAppendString(jsonLabel, "model", tmp->model) < 0 ||
+ virJSONValueObjectAppendString(jsonLabel, "label", tmp->label) < 0 ||
+ virJSONValueObjectAppendNumberUint(jsonLabel, "refcount", tmp->refcount) < 0)
+ goto error;
+
+ if (virJSONValueArrayAppend(jsonLabels, jsonLabel) < 0)
+ goto error;
+ jsonLabel = NULL;
+ }
+
+ if (virJSONValueObjectAppend(item, "labels", jsonLabels) < 0)
+ goto error;
+ jsonLabels = NULL;
+
+ if (virJSONValueArrayAppend(data->labels, item) < 0)
+ goto error;
+ item = NULL;
+
+ return;
+ error:
+ virJSONValueFree(jsonLabel);
+ virJSONValueFree(jsonLabels);
+ virJSONValueFree(item);
+ data->error = true;
+}
+
+
+/**
+ * virSeclabelSpacePreExecRestart:
+ *
+ * @space: object to dump
+ *
+ * Dumps virSeclabel object into JSON.
+ *
+ * Returns: a non-NULL pointer to JSON object on success,
+ * NULL on error
+ */
+virJSONValuePtr
+virSeclabelSpacePreExecRestart(virSeclabelSpacePtr space)
+{
+ virJSONValuePtr object = NULL;
+ virJSONValuePtr labels = NULL;
+ struct virSeclabelSpaceIteratorData data;
+
+ if (!space)
+ return NULL;
+
+ virSeclabelSpaceLock(space);
+
+ if (!(object = virJSONValueNewObject()))
+ return NULL;
+
+ if (!(labels = virJSONValueNewArray()))
+ goto error;
+
+ data.labels = labels;
+ data.error = false;
+ if (virHashForEach(space->labels, virSeclabelSpaceIterator, &data) < 0)
+ goto error;
+
+ if (virJSONValueObjectAppend(object, "seclabels", labels) < 0)
+ goto error;
+ /* From now on, @labels is contained in @object. Avoid double freeing it. */
+ labels = NULL;
+
+ virSeclabelSpaceUnlock(space);
+ return object;
+ error:
+ virSeclabelSpaceUnlock(space);
+ virJSONValueFree(labels);
+ virJSONValueFree(object);
+ return NULL;
+}
+
+
+/**
+ * virSeclabelSpacePostExecRestart:
+ *
+ * @object: JSON representation of internal state
+ *
+ * Read in JSON object, create new virSeclabelSpace object and restore its internal state from JSON.
+ *
+ * Returns: virSeclabelSpace object
+ * NULL on error
+ */
+virSeclabelSpacePtr
+virSeclabelSpacePostExecRestart(virJSONValuePtr object)
+{
+ virSeclabelSpacePtr ret;
+ virJSONValuePtr labels;
+ size_t i, npaths;
+
+ if (!(ret = virSeclabelSpaceNew()))
+ return NULL;
+
+ if (!(labels = virJSONValueObjectGetArray(object, "seclabels")))
+ goto error;
+
+ npaths = virJSONValueArraySize(labels);
+ for (i = 0; i < npaths; i++) {
+ virJSONValuePtr item = virJSONValueArrayGet(labels, i);
+ virJSONValuePtr arr = virJSONValueObjectGetArray(item, "labels");
+ const char *path = virJSONValueObjectGetString(item, "path");
+ size_t j, nlabels;
+
+ nlabels = virJSONValueArraySize(arr);
+
+ for (j = 0; j < nlabels; j++) {
+ virJSONValuePtr arr_item = virJSONValueArrayGet(arr, j);
+ const char *model = virJSONValueObjectGetString(arr_item, "model");
+ const char *label = virJSONValueObjectGetString(arr_item, "label");
+ virSeclabelPtr seclabel;
+
+ if (!(seclabel = virSeclabelNew(model, label)))
+ goto error;
+
+ if (virJSONValueObjectGetNumberUint(arr_item,
+ "refcount",
+ &seclabel->refcount) < 0) {
+ virSeclabelFree(seclabel);
+ goto error;
+ }
+
+ if (virSeclabelSpaceAdd(ret, path, seclabel) < 0) {
+ virSeclabelFree(seclabel);
+ goto error;
+ }
+ }
+ }
+
+ return ret;
+ error:
+ virSeclabelSpaceFree(ret);
+ return NULL;
+}
+
+
+/**
+ * virSeclabelSpaceRemember:
+ *
+ * @space: seclabel space object
+ * @path: path to remember
+ * @model: security model of @label ("selinux", "dac", etc.)
+ * @label: actual value to hold (e.g. "root:root")
+ *
+ * This function should remember the original label for a @path on the first
+ * call. Any subsequent call over the same @path and @model just increments the
+ * refcounter for the label (actual value of @label is ignored in this case).
+ *
+ * Returns: 0 on success
+ * -1 otherwise
+ */
+int
+virSeclabelSpaceRemember(virSeclabelSpacePtr space,
+ const char *path,
+ const char *model,
+ const char *label)
+{
+ virSeclabelPtr seclabel;
+ int ret = -1;
+
+ virSeclabelSpaceLock(space);
+ if ((seclabel = virSeclabelSpaceLookup(space, path, model))) {
+ /* We don't really care about label here. There already is an existing
+ * record for the @path and @model, so @label is likely to not have the
+ * original label anyway. */
+ seclabel->refcount++;
+ ret = 0;
+ goto cleanup;
+ }
+
+ if (!(seclabel = virSeclabelNew(model, label)))
+ goto cleanup;
+
+ if (virSeclabelSpaceAdd(space, path, seclabel) < 0) {
+ virSeclabelFree(seclabel);
+ goto cleanup;
+ }
+
+ ret = 0;
+ cleanup:
+ virSeclabelSpaceUnlock(space);
+ return ret;
+}
+
+
+/**
+ * virSeclabelSpaceRecall:
+ *
+ * @space: seclabel space object
+ * @path: path to recall
+ * @model: model to recall
+ * @label: the original value remembered
+ *
+ * Counterpart for virSeclabelSpaceRemember. Upon successful return (retval ==
+ * 0) @label is set to point to the original value remembered. The caller is
+ * responsible for freeing the @label when no longer needed.
+ *
+ * Returns: 1 if label found, but still in use (refcount > 1), @label not touched
+ * 0 if label found and not used anymore (refcount = 1), @label set
+ * -1 if no label was recorded with (@path, @model) tuple, @label not touched
+ */
+int
+virSeclabelSpaceRecall(virSeclabelSpacePtr space,
+ const char *path,
+ const char *model,
+ char **label)
+{
+ int ret = -1;
+ virSeclabelPtr seclabel;
+
+ virSeclabelSpaceLock(space);
+
+ if (!(seclabel = virSeclabelSpaceLookup(space, path, model)))
+ goto cleanup;
+
+ seclabel->refcount--;
+ if (seclabel->refcount) {
+ /* still in use */
+ ret = 1;
+ goto cleanup;
+ }
+
+ virSeclabelSpaceRemove(space, path, seclabel);
+ /* steal the label pointer before freeing */
+ *label = seclabel->label;
+ seclabel->label = NULL;
+ virSeclabelFree(seclabel);
+
+ ret = 0;
+ cleanup:
+ virSeclabelSpaceUnlock(space);
+ return ret;
+}
diff --git a/src/locking/lock_daemon_seclabels.h b/src/locking/lock_daemon_seclabels.h
new file mode 100644
index 0000000..3164206
--- /dev/null
+++ b/src/locking/lock_daemon_seclabels.h
@@ -0,0 +1,43 @@
+/*
+ * lock_daemon_seclabels.h: Security label mgmt
+ *
+ * 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 2.1 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: Michal Privoznik <mprivozn at redhat.com>
+ */
+
+#ifndef __VIR_LOCK_DAEMON_SECLABELS_H__
+# define __VIR_LOCK_DAEMON_SECLABELS_H__
+
+typedef struct _virSeclabelSpace virSeclabelSpace;
+typedef virSeclabelSpace *virSeclabelSpacePtr;
+
+void virSeclabelSpaceFree(virSeclabelSpacePtr space);
+virSeclabelSpacePtr virSeclabelSpaceNew(void);
+
+int virSeclabelSpaceRemember(virSeclabelSpacePtr space,
+ const char *path,
+ const char *model,
+ const char *label);
+int virSeclabelSpaceRecall(virSeclabelSpacePtr space,
+ const char *path,
+ const char *model,
+ char **label);
+
+virJSONValuePtr virSeclabelSpacePreExecRestart(virSeclabelSpacePtr space);
+virSeclabelSpacePtr virSeclabelSpacePostExecRestart(virJSONValuePtr object);
+#endif /* __VIR_LOCK_DAEMON_SECLABELS_H__ */
--
2.4.9
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