On 05/02/2012 07:44 AM, Daniel P. Berrange wrote:
From: "Daniel P. Berrange" <berrange@xxxxxxxxxx>
---
po/POTFILES.in | 1 +
src/Makefile.am | 3 +-
src/access/viraccessdriverselinux.c | 388 +++++++++++++++++++++++++++++++++++
src/access/viraccessdriverselinux.h | 28 +++
src/access/viraccessmanager.c | 2 +
5 files changed, 421 insertions(+), 1 deletion(-)
create mode 100644 src/access/viraccessdriverselinux.c
create mode 100644 src/access/viraccessdriverselinux.h
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 0c18fa0..7ab6dba 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -7,6 +7,7 @@ daemon/stream.c
gnulib/lib/gai_strerror.c
gnulib/lib/regcomp.c
src/access/viraccessdriverpolkit.c
+src/access/viraccessdriverselinux.c
src/access/viraccessmanager.c
src/conf/cpu_conf.c
src/conf/domain_conf.c
diff --git a/src/Makefile.am b/src/Makefile.am
index f9972ac..64398f0 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -537,7 +537,8 @@ ACCESS_DRIVER_SOURCES = \
access/viraccessdriver.h \
access/viraccessdrivernop.h access/viraccessdrivernop.c \
access/viraccessdriverstack.h access/viraccessdriverstack.c \
- access/viraccessdriverpolkit.h access/viraccessdriverpolkit.c
+ access/viraccessdriverpolkit.h access/viraccessdriverpolkit.c \
+ access/viraccessdriverselinux.h access/viraccessdriverselinux.c
ACCESS_DRIVER_POLKIT_POLICY = \
access/org.libvirt.domain.policy
diff --git a/src/access/viraccessdriverselinux.c b/src/access/viraccessdriverselinux.c
new file mode 100644
index 0000000..2c64aff
--- /dev/null
+++ b/src/access/viraccessdriverselinux.c
@@ -0,0 +1,388 @@
+/*
+ * viraccessdriverselinux.c: selinuxed access control driver
+ *
+ * Copyright (C) 2012 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <config.h>
+
+#include "access/viraccessdriverselinux.h"
+#include "memory.h"
+#include "command.h"
+#include "logging.h"
+#include "threads.h"
+#include "virterror_internal.h"
+
+#include <selinux/selinux.h>
+#include <selinux/avc.h>
+#include <selinux/av_permissions.h>
+#include <selinux/flask.h>
+
+
+#define VIR_FROM_THIS VIR_FROM_ACCESS
+#define virAccessError(code, ...) \
+ virReportErrorHelper(VIR_FROM_THIS, code, __FILE__, \
+ __FUNCTION__, __LINE__, __VA_ARGS__)
+
+static void virAccessDriverSELinuxAVCLog(const char *fmt, ...) ATTRIBUTE_FMT_PRINTF(1, 2);
+static void virAccessDriverSELinuxAVCLogAudit(void *data, security_class_t class, char *buf, size_t bufleft);
+static void *virAccessDriverSELinuxAVCCreateThread(void (*run) (void));
+static void virAccessDriverSELinuxAVCStopThread(void *thread);
+static void *virAccessDriverSELinuxAVCAllocLock(void);
+static void virAccessDriverSELinuxAVCGetLock(void *lock);
+static void virAccessDriverSELinuxAVCReleaseLock(void *lock);
+static void virAccessDriverSELinuxAVCFreeLock(void *lock);
+
+
+/* AVC callback structures for use in avc_init. */
+static const struct avc_memory_callback virAccessDriverSELinuxAVCMemCallbacks =
+{
+ .func_malloc = malloc,
+ .func_free = free,
+};
+static const struct avc_log_callback virAccessDriverSELinuxAVCLogCallbacks =
+{
+ .func_log = virAccessDriverSELinuxAVCLog,
+ .func_audit = virAccessDriverSELinuxAVCLogAudit,
+};
+static const struct avc_thread_callback virAccessDriverSELinuxAVCThreadCallbacks =
+{
+ .func_create_thread = virAccessDriverSELinuxAVCCreateThread,
+ .func_stop_thread = virAccessDriverSELinuxAVCStopThread,
+};
+static const struct avc_lock_callback virAccessDriverSELinuxAVCLockCallbacks =
+{
+ .func_alloc_lock = virAccessDriverSELinuxAVCAllocLock,
+ .func_get_lock = virAccessDriverSELinuxAVCGetLock,
+ .func_release_lock = virAccessDriverSELinuxAVCReleaseLock,
+ .func_free_lock = virAccessDriverSELinuxAVCFreeLock,
+};
+
+
+typedef struct _virAccessDriverSELinuxPrivate virAccessDriverSELinuxPrivate;
+typedef virAccessDriverSELinuxPrivate *virAccessDriverSELinuxPrivatePtr;
+
+struct _virAccessDriverSELinuxPrivate {
+ bool enabled;
+
+ /* Cache for AVCs */
+ struct avc_entry_ref aeref;
+
+ /* SID of the daemon */
+ security_id_t localSid;
+};
+
+
+static int virAccessDriverSELinuxSetup(virAccessManagerPtr manager)
+{
+ virAccessDriverSELinuxPrivatePtr priv = virAccessManagerGetPrivateData(manager);
+ int r;
+ security_context_t localCon;
+ int ret = -1;
+
+ if ((r = is_selinux_enabled()) < 0) {
+ virReportSystemError(errno, "%s",
+ _("Unable to determine if SELinux is enabled"));
+ return -1;
+ }
+ priv->enabled = r != 0;
+ priv->localSid = SECSID_WILD;
+
+ avc_entry_ref_init(&priv->aeref);
+
+ if (avc_init("avc",
+ &virAccessDriverSELinuxAVCMemCallbacks,
+ &virAccessDriverSELinuxAVCLogCallbacks,
+ &virAccessDriverSELinuxAVCThreadCallbacks,
+ &virAccessDriverSELinuxAVCLockCallbacks) < 0) {
It looks like avc_init is deprecated.
+ virReportSystemError(errno, "%s",
+ _("Unable to initialize AVC system"));
+ goto cleanup;
+ }
+
+ if (getcon(&localCon) < 0) {
+ virReportSystemError(errno, "%s",
+ _("Unable to get context of daemon"));
+ goto cleanup;
+ }
+
+ if (avc_context_to_sid(localCon, &priv->localSid) < 0) {
+ virReportSystemError(errno,
+ _("Unable to convert context %s to SID"),
+ (char*)localCon);
+ goto cleanup;
+ }
+ VIR_FREE(localCon);
+
+ ret = 0;
+cleanup:
+ if (ret < 0)
+ priv->localSid = SECSID_WILD;
+ freecon(localCon);
+ return ret;
+}
+
+
+static void virAccessDriverSELinuxCleanup(virAccessManagerPtr manager)
+{
+ virAccessDriverSELinuxPrivatePtr priv = virAccessManagerGetPrivateData(manager);
+
+ priv->localSid = SECSID_WILD;
+}
+
+
+static security_id_t
+virAccessDriverSELinuxGetClientSID(void)
+{
+ virIdentityPtr identity = virAccessManagerGetEffectiveIdentity();
+ const char *seccon = NULL;
+ security_id_t sid = SECSID_WILD;
+
+ if (!identity) {
+ virAccessError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("No identity available"));
+ return NULL;
+ }
+ if (virIdentityGetAttr(identity, VIR_IDENTITY_ATTR_SECURITY_CONTEXT, &seccon) < 0)
+ goto cleanup;
+
+ if (!seccon) {
+ virAccessError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("No security context available"));
+ goto cleanup;
+ }
+
+ if (avc_context_to_sid((security_context_t)seccon, &sid) < 0) {
+ virReportSystemError(errno,
+ _("Unable to convert context %s to SID"),
+ seccon);
+ sid = SECSID_WILD;
+ goto cleanup;
+ }
+
+cleanup:
+ virIdentityFree(identity);
+ return sid;
+}
+
+
+static security_class_t
+virAccessDriverSELinuxGetObjectClass(const char *typename)
+{
+ security_class_t ret;
+
+ if ((ret = string_to_security_class(typename)) == 0) {
+ virReportSystemError(errno,
+ _("Unable to find security class '%s'"), typename);
+ return 0;
+ }
+
+ return ret;
+}
+
+
+static access_vector_t
+virAccessDriverSELinuxGetObjectPerm(const char *avname, const char *typename, security_class_t objectClass)
+{
+ access_vector_t ret;
+
+ if (objectClass == 0)
+ return 0;
+
+ if ((ret = string_to_av_perm(objectClass, avname)) == 0) {
+ virReportSystemError(errno,
+ _("Unable to find access vector '%s' for '%s'"), avname, typename);
+ return 0;
+ }
+
+ return ret;
+}
+
+static bool
+virAccessDriverSELinuxCheck(virAccessManagerPtr manager,
+ security_id_t objectSid,
+ const char *typename,
+ const char *avname)
+{
+ virAccessDriverSELinuxPrivatePtr priv = virAccessManagerGetPrivateData(manager);
+ security_id_t clientSid = virAccessDriverSELinuxGetClientSID();
+ security_class_t objectClass = virAccessDriverSELinuxGetObjectClass(typename);
+ access_vector_t objectVector = virAccessDriverSELinuxGetObjectPerm(avname, typename, objectClass);
+ int ret = false;
+
+ if (clientSid == SECSID_WILD ||
+ objectClass == 0 ||
+ objectVector == 0) {
So if the client has the wildcard sid it gets access. That makes sense.
What about objectClass == 0 and objectVector == 0? I'm thinking these
cover the case where the MAC admin has modified the enforcing policy and
removed the corresponding class/perm definitions. It just makes me feel
a little uncomfortable that we could accidentally fall through and grant
access here, perhaps due to a coding error on a
virAccessManagerCheckConnect or virAccessManagerCheckDomain call.
+ if (security_deny_unknown() == 0) {
+ VIR_WARN("Allow access, because policy does not deny unknown objects");
+ ret = true;
+ }
+ goto cleanup;
+ }
+
+ if (avc_has_perm(clientSid, objectSid,
+ objectClass, objectVector,
+ &priv->aeref, NULL) < 0) {
+ int save_errno = errno;
+ if (security_getenforce() == 0) {
+ char ebuf[1024];
+ VIR_WARN("Ignoring denial in non-enforcing mode: %s",
+ virStrerror(save_errno, ebuf, sizeof(ebuf)));
+ ret = true;
+ goto cleanup;
+ }
+ switch (save_errno) {
+ case EACCES:
+ virAccessError(VIR_ERR_ACCESS_DENIED, "%s",
+ _("SELinux denying due to security policy"));
+ break;
+ case EINVAL:
+ virAccessError(VIR_ERR_ACCESS_DENIED, "%s",
+ _("SELinux denying due to invalid security context"));
+ break;
+ default:
+ virReportSystemError(errno, "%s",
+ _("SELinux denying"));
+ break;
+ }
+ goto cleanup;
+ }
+
+ ret = true;
+
+cleanup:
+ return ret;
+}
+
+
+static bool
+virAccessDriverSELinuxCheckConnect(virAccessManagerPtr manager,
+ virAccessPermConnect av)
+{
+ virAccessDriverSELinuxPrivatePtr priv = virAccessManagerGetPrivateData(manager);
+
+ /* There's no object to use for targetSid here, so we
+ * instead use the daemon's context as the targetSid */
+ return virAccessDriverSELinuxCheck(manager,
+ priv->localSid,
+ "connect",
+ virAccessPermConnectTypeToString(av));
+}
+
+
+static bool
+virAccessDriverSELinuxCheckDomain(virAccessManagerPtr manager,
+ virDomainDefPtr def ATTRIBUTE_UNUSED,
+ virAccessPermDomain av)
+{
+ security_id_t objectSid = 0; /* XXX get from 'def' */
+
+ return virAccessDriverSELinuxCheck(manager,
+ objectSid,
+ "domain",
+ virAccessPermDomainTypeToString(av));
+}
+
+
+
+static void virAccessDriverSELinuxAVCLog(const char *fmt, ...)
+{
+ va_list ap;
+ va_start(ap, fmt);
+ virLogVMessage("avc", VIR_LOG_WARN,__func__, __LINE__, 0, fmt, ap);
+ va_end(ap);
+}
+
+
+static void virAccessDriverSELinuxAVCLogAudit(void *data ATTRIBUTE_UNUSED,
+ security_class_t class ATTRIBUTE_UNUSED,
+ char *buf ATTRIBUTE_UNUSED,
+ size_t bufleft ATTRIBUTE_UNUSED)
+{
+}
+
+
+static void *virAccessDriverSELinuxAVCCreateThread(void (*run) (void))
+{
+ virThreadPtr thread;
+
+ if (VIR_ALLOC(thread) < 0) {
+ virReportOOMError();
+ return NULL;
+ }
+
+ if (virThreadCreate(thread, false, (virThreadFunc)run, NULL) < 0) {
+ virReportSystemError(errno, "%s",
+ _("Unable to create thread"));
+ VIR_FREE(thread);
+ }
+
+ return thread;
+}
+
+
+static void virAccessDriverSELinuxAVCStopThread(void *thread)
+{
+ virThreadCancel(thread);
+ VIR_FREE(thread);
+}
+
+
+static void *virAccessDriverSELinuxAVCAllocLock(void)
+{
+ virMutexPtr lock;
+ if (VIR_ALLOC(lock) < 0) {
+ virReportOOMError();
+ return NULL;
+ }
+ if (virMutexInit(lock) < 0) {
+ virReportSystemError(errno, "%s",
+ _("Unable to initialize mutex"));
+ VIR_FREE(lock);
+ return NULL;
+ }
+ return lock;
+}
+
+
+static void virAccessDriverSELinuxAVCGetLock(void *lock)
+{
+ virMutexLock(lock);
+}
+
+
+static void virAccessDriverSELinuxAVCReleaseLock(void *lock)
+{
+ virMutexUnlock(lock);
+}
+
+
+static void virAccessDriverSELinuxAVCFreeLock(void *lock)
+{
+ virMutexDestroy(lock);
+ VIR_FREE(lock);
+}
+
+
+virAccessDriver accessDriverSELinux = {
+ .privateDataLen = sizeof(virAccessDriverSELinuxPrivate),
+ .name = "selinux",
+ .setup = virAccessDriverSELinuxSetup,
+ .cleanup = virAccessDriverSELinuxCleanup,
+ .checkConnect = virAccessDriverSELinuxCheckConnect,
+ .checkDomain = virAccessDriverSELinuxCheckDomain,
+};
diff --git a/src/access/viraccessdriverselinux.h b/src/access/viraccessdriverselinux.h
new file mode 100644
index 0000000..3a53686
--- /dev/null
+++ b/src/access/viraccessdriverselinux.h
@@ -0,0 +1,28 @@
+/*
+ * viraccessdriverselinux.h: selinuxed access control driver
+ *
+ * Copyright (C) 2012 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef __VIR_ACCESS_DRIVER_SELINUX_H__
+# define __VIR_ACCESS_DRIVER_SELINUX_H__
+
+# include "access/viraccessdriver.h"
+
+extern virAccessDriver accessDriverSELinux;
+
+#endif /* __VIR_ACCESS_DRIVER_SELINUX_H__ */
diff --git a/src/access/viraccessmanager.c b/src/access/viraccessmanager.c
index e7444d5..4b215c4 100644
--- a/src/access/viraccessmanager.c
+++ b/src/access/viraccessmanager.c
@@ -30,6 +30,7 @@
#include "access/viraccessdrivernop.h"
#include "access/viraccessdriverstack.h"
#include "access/viraccessdriverpolkit.h"
+#include "access/viraccessdriverselinux.h"
#include "logging.h"
#define VIR_FROM_THIS VIR_FROM_ACCESS
@@ -218,6 +219,7 @@ static virAccessManagerPtr virAccessManagerNewDriver(virAccessDriverPtr drv)
static virAccessDriverPtr accessDrivers[] = {
&accessDriverNop,
&accessDriverPolkit,
+ &accessDriverSELinux,
};
--
Regards,
Corey
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