Add two new security label types

Curently security labels can be of type 'dynamic' or 'static'.
If no security label is given, then 'dynamic' is assumed. The
current code takes advantage of this default, and avoids even
saving <seclabel> elements with type='dynamic' to disk. This
means if you temporarily change security driver, the guests
can all still start.

With the introduction of sVirt to LXC though, there needs to be
a new default of 'none' to allow unconfined LXC containers.

This patch introduces two new security label types

 - default:  the host configuration decides whether to run the
             guest with type 'none' or 'dynamic' at guest start
 - none:     the guest will run unconfined by security policy

The 'none' label type will obviously be undesirable for some
deployments, so a new qemu.conf option allows a host admin to
mandate confined guests. It is also possible to turn off default
confinement

  security_default_confined = 1|0  (default == 1)
  security_require_confined = 1|0  (default == 0)

* src/conf/domain_conf.c, src/conf/domain_conf.h: Add new
  seclabel types
* src/security/security_manager.c, src/security/security_manager.h:
  Set default sec label types
* src/security/security_selinux.c: Handle 'none' seclabel type
* src/qemu/qemu.conf, src/qemu/qemu_conf.c, src/qemu/qemu_conf.h,
  src/qemu/libvirtd_qemu.aug: New security config options
* src/qemu/qemu_driver.c: Tell security driver about default
  config

docs/formatdomain.html.in

@@ -3539,16 +3539,18 @@ qemu-kvm -net nic,model=? /dev/null
 
     <p>
       The <code>seclabel</code> element allows control over the
-      operation of the security drivers. There are two basic
+      operation of the security drivers. There are three basic
-      modes of operation, dynamic where libvirt automatically
+      modes of operation, 'dynamic' where libvirt automatically
-      generates a unique security label, or static where the
+      generates a unique security label, 'static' where the
-      application/administrator chooses the labels. With dynamic
+      application/administrator chooses the labels, or 'none'
+      where confinement is disabled. With dynamic
       label generation, libvirt will always automatically
       relabel any resources associated with the virtual machine.
       With static label assignment, by default, the administrator
       or application must ensure labels are set correctly on any
       resources, however, automatic relabeling can be enabled
-      if desired.
+      if desired.  <span class="since">'dynamic' since 0.6.1, 'static'
+      since 0.6.2, and 'none' since 0.9.10.</span>
     </p>
 
     <p>
@@ -3570,8 +3572,17 @@ qemu-kvm -net nic,model=? /dev/null
   &lt;seclabel type='static' model='selinux' relabel='yes'&gt;
     &lt;label&gt;system_u:system_r:svirt_t:s0:c392,c662&lt;/label&gt;
   &lt;/seclabel&gt;
+
+  &lt;seclabel type='none'/&gt;
     </pre>
 
+    <p>
+      If no 'type' attribute is provided in the input XML, then
+      the security driver default setting will be used, which
+      may be either 'none' or 'dynamic'. If a 'baselabel' is set
+      but no 'type' is set, then the type is presumed to be 'dynamic'
+    </p>
+
     <p>
       When viewing the XML for a running guest with automatic
       resource relabeling active, an additional XML element,
@@ -3581,9 +3592,9 @@ qemu-kvm -net nic,model=? /dev/null
     </p>
     <dl>
       <dt><code>type</code></dt>
-      <dd>Either <code>static</code> or <code>dynamic</code> to determine
+      <dd>Either <code>static</code>, <code>dynamic</code> or <code>none</code>
-        whether libvirt automatically generates a unique security label
+        to determine whether libvirt automatically generates a unique security
-        or not.
+        label or not.
       </dd>
       <dt><code>model</code></dt>
       <dd>A valid security model name, matching the currently

docs/schemas/domaincommon.rng

@@ -129,6 +129,11 @@
             </optional>
           </interleave>
         </group>
+        <group>
+          <attribute name='type'>
+            <value>none</value>
+          </attribute>
+        </group>
       </choice>
     </element>
   </define>

po/POTFILES.in

@@ -90,6 +90,7 @@ src/secret/secret_driver.c
 src/security/security_apparmor.c
 src/security/security_dac.c
 src/security/security_driver.c
+src/security/security_manager.c
 src/security/security_selinux.c
 src/security/virt-aa-helper.c
 src/storage/parthelper.c

src/conf/domain_conf.c

@@ -564,6 +564,8 @@ VIR_ENUM_IMPL(virDomainCrashedReason, VIR_DOMAIN_CRASHED_LAST,
               "unknown")
 
 VIR_ENUM_IMPL(virDomainSeclabel, VIR_DOMAIN_SECLABEL_LAST,
+              "default",
+              "none",
               "dynamic",
               "static")
 
@@ -2585,13 +2587,15 @@ virSecurityLabelDefParseXML(virSecurityLabelDefPtr def,
                              "%s", _("missing security type"));
         goto error;
     }
+
     def->type = virDomainSeclabelTypeFromString(p);
     VIR_FREE(p);
-    if (def->type < 0) {
+    if (def->type <= 0) {
         virDomainReportError(VIR_ERR_XML_ERROR,
                              "%s", _("invalid security type"));
         goto error;
     }
+
     p = virXPathStringLimit("string(./seclabel/@relabel)",
                             VIR_SECURITY_LABEL_BUFLEN-1, ctxt);
     if (p != NULL) {
@@ -2612,8 +2616,15 @@ virSecurityLabelDefParseXML(virSecurityLabelDefPtr def,
                                  "%s", _("dynamic label type must use resource relabeling"));
             goto error;
         }
+        if (def->type == VIR_DOMAIN_SECLABEL_NONE &&
+            !def->norelabel) {
+            virDomainReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                                 "%s", _("resource relabeling is not compatible with 'none' label type"));
+            goto error;
+        }
     } else {
-        if (def->type == VIR_DOMAIN_SECLABEL_STATIC)
+        if (def->type == VIR_DOMAIN_SECLABEL_STATIC ||
+            def->type == VIR_DOMAIN_SECLABEL_NONE)
             def->norelabel = true;
         else
             def->norelabel = false;
@@ -2648,12 +2659,16 @@ virSecurityLabelDefParseXML(virSecurityLabelDefPtr def,
         def->imagelabel = p;
     }
 
-    /* Only parse baselabel, for dynamic label */
+    /* Only parse baselabel, for dynamic or none label types */
-    if (def->type == VIR_DOMAIN_SECLABEL_DYNAMIC) {
+    if (def->type == VIR_DOMAIN_SECLABEL_DYNAMIC ||
+        def->type == VIR_DOMAIN_SECLABEL_NONE) {
         p = virXPathStringLimit("string(./seclabel/baselabel[1])",
                                 VIR_SECURITY_LABEL_BUFLEN-1, ctxt);
-        if (p != NULL)
+        if (p != NULL) {
             def->baselabel = p;
+            /* Forces none type to dynamic for back compat */
+            def->type = VIR_DOMAIN_SECLABEL_DYNAMIC;
+        }
     }
 
     /* Only parse model, if static labelling, or a base
@@ -9923,24 +9938,32 @@ virDomainLifecycleDefFormat(virBufferPtr buf,
 }
 
 
-static int
+static void
-virSecurityLabelDefFormat(virBufferPtr buf, virSecurityLabelDefPtr def,
+virSecurityLabelDefFormat(virBufferPtr buf, virSecurityLabelDefPtr def)
-                          unsigned int flags)
 {
     const char *sectype = virDomainSeclabelTypeToString(def->type);
-    int ret = -1;
 
     if (!sectype)
-        goto cleanup;
+        return;
+
+    if (def->type == VIR_DOMAIN_SECLABEL_DEFAULT)
+        return;
+
+    virBufferAsprintf(buf, "<seclabel type='%s'",
+                      sectype);
+    virBufferEscapeString(buf, " model='%s'", def->model);
+
+    virBufferAsprintf(buf, " relabel='%s'",
+                      def->norelabel ? "no" : "yes");
+
+    if (def->type == VIR_DOMAIN_SECLABEL_NONE) {
+        virBufferAddLit(buf, "/>\n");
+        return;
+    }
+
+    if (def->label || def->imagelabel || def->baselabel) {
+        virBufferAddLit(buf, ">\n");
 
-    if (def->type == VIR_DOMAIN_SECLABEL_DYNAMIC &&
-        !def->baselabel &&
-        (flags & VIR_DOMAIN_XML_INACTIVE)) {
-        /* This is the default for inactive xml, so nothing to output.  */
-    } else {
-        virBufferAsprintf(buf, "<seclabel type='%s' model='%s' relabel='%s'>\n",
-                          sectype, def->model,
-                          def->norelabel ? "no" : "yes");
         virBufferEscapeString(buf, "  <label>%s</label>\n",
                               def->label);
         if (!def->norelabel)
@@ -9950,10 +9973,9 @@ virSecurityLabelDefFormat(virBufferPtr buf, virSecurityLabelDefPtr def,
             virBufferEscapeString(buf, "  <baselabel>%s</baselabel>\n",
                                   def->baselabel);
         virBufferAddLit(buf, "</seclabel>\n");
+    } else {
+        virBufferAddLit(buf, "/>\n");
     }
-    ret = 0;
-cleanup:
-    return ret;
 }
 
 
@@ -11957,12 +11979,9 @@ virDomainDefFormatInternal(virDomainDefPtr def,
 
     virBufferAddLit(buf, "  </devices>\n");
 
-    if (def->seclabel.model) {
+    virBufferAdjustIndent(buf, 2);
-        virBufferAdjustIndent(buf, 2);
+    virSecurityLabelDefFormat(buf, &def->seclabel);
-        if (virSecurityLabelDefFormat(buf, &def->seclabel, flags) < 0)
+    virBufferAdjustIndent(buf, -2);
-            goto cleanup;
-        virBufferAdjustIndent(buf, -2);
-    }
 
     if (def->namespaceData && def->ns.format) {
         if ((def->ns.format)(buf, def->namespaceData) < 0)

src/conf/domain_conf.h

@@ -175,6 +175,8 @@ struct _virDomainDeviceInfo {
 };
 
 enum virDomainSeclabelType {
+    VIR_DOMAIN_SECLABEL_DEFAULT,
+    VIR_DOMAIN_SECLABEL_NONE,
     VIR_DOMAIN_SECLABEL_DYNAMIC,
     VIR_DOMAIN_SECLABEL_STATIC,
 

src/qemu/libvirtd_qemu.aug

@@ -33,6 +33,8 @@ module Libvirtd_qemu =
                  | bool_entry "vnc_sasl"
                  | str_entry "vnc_sasl_dir"
                  | str_entry "security_driver"
+                 | bool_entry "security_default_confined"
+                 | bool_entry "security_require_confined"
                  | str_entry "user"
                  | str_entry "group"
                  | bool_entry "dynamic_ownership"

src/qemu/qemu.conf

@@ -138,6 +138,14 @@
 #
 # security_driver = "selinux"
 
+# If set to non-zero, then the default security labeling
+# will make guests confined. If set to zero, then guests
+# will be unconfined by default. Defaults to 1.
+# security_default_confined = 1
+
+# If set to non-zero, then attempts to create unconfined
+# guests will be blocked. Defaults to 0.
+# security_require_confined = 1
 
 # The user ID for QEMU processes run by the system instance.
 #user = "root"

src/qemu/qemu_conf.c

@@ -75,6 +75,8 @@ int qemudLoadDriverConfig(struct qemud_driver *driver,
     int i;
 
     /* Setup critical defaults */
+    driver->securityDefaultConfined = true;
+    driver->securityRequireConfined = false;
     driver->dynamicOwnership = 1;
     driver->clearEmulatorCapabilities = 1;
 
@@ -195,6 +197,15 @@ int qemudLoadDriverConfig(struct qemud_driver *driver,
         }
     }
 
+    p = virConfGetValue (conf, "security_default_confined");
+    CHECK_TYPE ("security_default_confined", VIR_CONF_LONG);
+    if (p) driver->securityDefaultConfined = p->l;
+
+    p = virConfGetValue (conf, "security_require_confined");
+    CHECK_TYPE ("security_require_confined", VIR_CONF_LONG);
+    if (p) driver->securityRequireConfined = p->l;
+
+
     p = virConfGetValue (conf, "vnc_sasl");
     CHECK_TYPE ("vnc_sasl", VIR_CONF_LONG);
     if (p) driver->vncSASL = p->l;

src/qemu/qemu_conf.h

@@ -115,6 +115,8 @@ struct qemud_driver {
     virDomainEventStatePtr domainEventState;
 
     char *securityDriverName;
+    bool securityDefaultConfined;
+    bool securityRequireConfined;
     virSecurityManagerPtr securityManager;
 
     char *saveImageFormat;

src/qemu/qemu_driver.c

@@ -210,7 +210,10 @@ static int
 qemuSecurityInit(struct qemud_driver *driver)
 {
     virSecurityManagerPtr mgr = virSecurityManagerNew(driver->securityDriverName,
-                                                      driver->allowDiskFormatProbing);
+                                                      driver->allowDiskFormatProbing,
+                                                      driver->securityDefaultConfined,
+                                                      driver->securityRequireConfined);
+
     if (!mgr)
         goto error;
 
@@ -218,6 +221,8 @@ qemuSecurityInit(struct qemud_driver *driver)
         virSecurityManagerPtr dac = virSecurityManagerNewDAC(driver->user,
                                                              driver->group,
                                                              driver->allowDiskFormatProbing,
+                                                             driver->securityDefaultConfined,
+                                                             driver->securityRequireConfined,
                                                              driver->dynamicOwnership);
         if (!dac)
             goto error;

src/security/security_manager.c

@@ -36,10 +36,14 @@
 struct _virSecurityManager {
     virSecurityDriverPtr drv;
     bool allowDiskFormatProbing;
+    bool defaultConfined;
+    bool requireConfined;
 };
 
 static virSecurityManagerPtr virSecurityManagerNewDriver(virSecurityDriverPtr drv,
-                                                         bool allowDiskFormatProbing)
+                                                         bool allowDiskFormatProbing,
+                                                         bool defaultConfined,
+                                                         bool requireConfined)
 {
     virSecurityManagerPtr mgr;
 
@@ -50,6 +54,8 @@ static virSecurityManagerPtr virSecurityManagerNewDriver(virSecurityDriverPtr dr
 
     mgr->drv = drv;
     mgr->allowDiskFormatProbing = allowDiskFormatProbing;
+    mgr->defaultConfined = defaultConfined;
+    mgr->requireConfined = requireConfined;
 
     if (drv->open(mgr) < 0) {
         virSecurityManagerFree(mgr);
@@ -64,7 +70,9 @@ virSecurityManagerPtr virSecurityManagerNewStack(virSecurityManagerPtr primary,
 {
     virSecurityManagerPtr mgr =
         virSecurityManagerNewDriver(&virSecurityDriverStack,
-                                    virSecurityManagerGetAllowDiskFormatProbing(primary));
+                                    virSecurityManagerGetAllowDiskFormatProbing(primary),
+                                    virSecurityManagerGetDefaultConfined(primary),
+                                    virSecurityManagerGetRequireConfined(primary));
 
     if (!mgr)
         return NULL;
@@ -78,11 +86,15 @@ virSecurityManagerPtr virSecurityManagerNewStack(virSecurityManagerPtr primary,
 virSecurityManagerPtr virSecurityManagerNewDAC(uid_t user,
                                                gid_t group,
                                                bool allowDiskFormatProbing,
+                                               bool defaultConfined,
+                                               bool requireConfined,
                                                bool dynamicOwnership)
 {
     virSecurityManagerPtr mgr =
         virSecurityManagerNewDriver(&virSecurityDriverDAC,
-                                    allowDiskFormatProbing);
+                                    allowDiskFormatProbing,
+                                    defaultConfined,
+                                    requireConfined);
 
     if (!mgr)
         return NULL;
@@ -95,13 +107,18 @@ virSecurityManagerPtr virSecurityManagerNewDAC(uid_t user,
 }
 
 virSecurityManagerPtr virSecurityManagerNew(const char *name,
-                                            bool allowDiskFormatProbing)
+                                            bool allowDiskFormatProbing,
+                                            bool defaultConfined,
+                                            bool requireConfined)
 {
     virSecurityDriverPtr drv = virSecurityDriverLookup(name);
     if (!drv)
         return NULL;
 
-    return virSecurityManagerNewDriver(drv, allowDiskFormatProbing);
+    return virSecurityManagerNewDriver(drv,
+                                       allowDiskFormatProbing,
+                                       defaultConfined,
+                                       requireConfined);
 }
 
 
@@ -149,6 +166,16 @@ bool virSecurityManagerGetAllowDiskFormatProbing(virSecurityManagerPtr mgr)
     return mgr->allowDiskFormatProbing;
 }
 
+bool virSecurityManagerGetDefaultConfined(virSecurityManagerPtr mgr)
+{
+    return mgr->defaultConfined;
+}
+
+bool virSecurityManagerGetRequireConfined(virSecurityManagerPtr mgr)
+{
+    return mgr->requireConfined;
+}
+
 int virSecurityManagerRestoreImageLabel(virSecurityManagerPtr mgr,
                                         virDomainDefPtr vm,
                                         virDomainDiskDefPtr disk)
@@ -248,6 +275,20 @@ int virSecurityManagerRestoreSavedStateLabel(virSecurityManagerPtr mgr,
 int virSecurityManagerGenLabel(virSecurityManagerPtr mgr,
                                virDomainDefPtr vm)
 {
+    if (vm->seclabel.type == VIR_DOMAIN_SECLABEL_DEFAULT) {
+        if (mgr->defaultConfined)
+            vm->seclabel.type = VIR_DOMAIN_SECLABEL_DYNAMIC;
+        else
+            vm->seclabel.type = VIR_DOMAIN_SECLABEL_NONE;
+    }
+
+    if ((vm->seclabel.type == VIR_DOMAIN_SECLABEL_NONE) &&
+        mgr->requireConfined) {
+        virSecurityReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                               _("Unconfined guests are not allowed on this host"));
+        return -1;
+    }
+
     if (mgr->drv->domainGenSecurityLabel)
         return mgr->drv->domainGenSecurityLabel(mgr, vm);
 

src/security/security_manager.h

@@ -32,7 +32,9 @@ typedef struct _virSecurityManager virSecurityManager;
 typedef virSecurityManager *virSecurityManagerPtr;
 
 virSecurityManagerPtr virSecurityManagerNew(const char *name,
-                                            bool allowDiskFormatProbing);
+                                            bool allowDiskFormatProbing,
+                                            bool defaultConfined,
+                                            bool requireConfined);
 
 virSecurityManagerPtr virSecurityManagerNewStack(virSecurityManagerPtr primary,
                                                  virSecurityManagerPtr secondary);
@@ -40,6 +42,8 @@ virSecurityManagerPtr virSecurityManagerNewStack(virSecurityManagerPtr primary,
 virSecurityManagerPtr virSecurityManagerNewDAC(uid_t user,
                                                gid_t group,
                                                bool allowDiskFormatProbing,
+                                               bool defaultConfined,
+                                               bool requireConfined,
                                                bool dynamicOwnership);
 
 void *virSecurityManagerGetPrivateData(virSecurityManagerPtr mgr);
@@ -49,6 +53,8 @@ void virSecurityManagerFree(virSecurityManagerPtr mgr);
 const char *virSecurityManagerGetDOI(virSecurityManagerPtr mgr);
 const char *virSecurityManagerGetModel(virSecurityManagerPtr mgr);
 bool virSecurityManagerGetAllowDiskFormatProbing(virSecurityManagerPtr mgr);
+bool virSecurityManagerGetDefaultConfined(virSecurityManagerPtr mgr);
+bool virSecurityManagerGetRequireConfined(virSecurityManagerPtr mgr);
 
 int virSecurityManagerRestoreImageLabel(virSecurityManagerPtr mgr,
                                         virDomainDefPtr def,

src/security/security_selinux.c

@@ -171,6 +171,7 @@ SELinuxGenSecurityLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
     int c1 = 0;
     int c2 = 0;
     context_t ctx = NULL;
+    const char *range;
 
     if ((def->seclabel.type == VIR_DOMAIN_SECLABEL_DYNAMIC) &&
         !def->seclabel.baselabel &&
@@ -201,7 +202,8 @@ SELinuxGenSecurityLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
         return rc;
     }
 
-    if (def->seclabel.type == VIR_DOMAIN_SECLABEL_STATIC) {
+    switch (def->seclabel.type) {
+    case VIR_DOMAIN_SECLABEL_STATIC:
         if (!(ctx = context_new(def->seclabel.label)) ) {
             virReportSystemError(errno,
                                  _("unable to allocate socket security context '%s'"),
@@ -209,13 +211,15 @@ SELinuxGenSecurityLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
             return rc;
         }
 
-        const char *range = context_range_get(ctx);
+        range = context_range_get(ctx);
         if (!range ||
             !(mcs = strdup(range))) {
             virReportOOMError();
             goto cleanup;
         }
-    } else {
+        break;
+
+    case VIR_DOMAIN_SECLABEL_DYNAMIC:
         do {
             c1 = virRandomBits(10);
             c2 = virRandomBits(10);
@@ -247,14 +251,28 @@ SELinuxGenSecurityLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
                                    _("cannot generate selinux context for %s"), mcs);
             goto cleanup;
         }
-    }
+        break;
-    def->seclabel.imagelabel = SELinuxGenNewContext(default_image_context, mcs);
+
-    if (!def->seclabel.imagelabel)  {
+    case VIR_DOMAIN_SECLABEL_NONE:
+        /* no op */
+        break;
+
+    default:
         virSecurityReportError(VIR_ERR_INTERNAL_ERROR,
-                               _("cannot generate selinux context for %s"), mcs);
+                               _("unexpected security label type '%s'"),
+                               virDomainSeclabelTypeToString(def->seclabel.type));
         goto cleanup;
     }
 
+    if (!def->seclabel.norelabel) {
+        def->seclabel.imagelabel = SELinuxGenNewContext(default_image_context, mcs);
+        if (!def->seclabel.imagelabel)  {
+            virSecurityReportError(VIR_ERR_INTERNAL_ERROR,
+                                   _("cannot generate selinux context for %s"), mcs);
+            goto cleanup;
+        }
+    }
+
     if (!def->seclabel.model &&
         !(def->seclabel.model = strdup(SECURITY_SELINUX_NAME))) {
         virReportOOMError();

tests/seclabeltest.c

@@ -13,7 +13,7 @@ main (int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED)
     virSecurityManagerPtr mgr;
     const char *doi, *model;
 
-    mgr = virSecurityManagerNew(NULL, false);
+    mgr = virSecurityManagerNew(NULL, false, true, true);
     if (mgr == NULL) {
         fprintf (stderr, "Failed to start security driver");
         exit (-1);