qemu: Read back the profile name after creation of a TPM instance

Get the JSON profile that the swtpm instance was created with from the
output of 'swtpm socket --tpm2 --print-info 0x20 --tpmstate ...'. Get the
name of the profile from the JSON and set it in the current and persistent
emulator descriptions as 'name' attribute and have the persistent
description stored with this update. The user should avoid setting this
'name' attribute since it is meant to be read-only. The following is
an example of how the XML could look like:

  <profile source='local:restricted' name='custom:restricted'/>

If the user provided no profile node, and therefore swtpm_setup picked its
default profile, the XML may now shows the 'name' attribute with the name
of the profile. This makes the 'source' attribute now optional.

  <profile name='default-v1'/>

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

docs/formatdomain.rst

@@ -8135,7 +8135,7 @@ Example: usage of the TPM Emulator
            <active_pcr_banks>
                <sha256/>
            </active_pcr_banks>
-           <profile source='local:restricted' removeDisabled='check'/>
+           <profile source='local:restricted' removeDisabled='check' name='custom:restricted'/>
          </backend>
        </tpm>
      </devices>
@@ -8233,12 +8233,14 @@ Example: usage of the TPM Emulator
 ``profile``
    The ``profile`` node is used to set a profile for a TPM 2.0 given in the
    source attribute. This profile will be set when the TPM is initially
-   created and after that cannot be changed anymore. If no profile is provided,
-   then swtpm will use the latest built-in 'default' profile or the default
-   profile set in swtpm_setup.conf. Otherwise swtpm_setup will search for a
-   profile with the given name with appended .json suffix in a configurable
-   local and then in a distro directory. If none could be found in either, it
-   will fall back trying to use a built-in one.
+   created and after that cannot be changed anymore. Once a profile has been
+   set the name attribute will be updated with the name of the profile that
+   is running. If no profile is provided, then swtpm will use the latest
+   built-in 'default' profile or the default profile set in swtpm_setup.conf.
+   Otherwise swtpm_setup will search for a profile with the given name with
+   appended .json suffix in a configurable local and then in a distro
+   directory. If none could be found in either, it will fall back trying to
+   use a built-in one.
 
    The built-in 'null' profile provides backwards compatibility with
    libtpms v0.9 but also restricts the user to use only TPM features that were

src/conf/domain_conf.c

@@ -3479,6 +3479,7 @@ void virDomainTPMDefFree(virDomainTPMDef *def)
         g_free(def->data.emulator.logfile);
         virBitmapFree(def->data.emulator.activePcrBanks);
         g_free(def->data.emulator.profile.source);
+        g_free(def->data.emulator.profile.name);
         break;
     case VIR_DOMAIN_TPM_TYPE_EXTERNAL:
         virObjectUnref(def->data.external.source);
@@ -10925,10 +10926,7 @@ virDomainTPMDefParseXML(virDomainXMLOption *xmlopt,
 
         if ((profile = virXPathNode("./backend/profile[1]", ctxt))) {
             def->data.emulator.profile.source = virXMLPropString(profile, "source");
-            if (!def->data.emulator.profile.source) {
-                virReportError(VIR_ERR_XML_ERROR, "%s", _("missing profile source"));
-                goto error;
-            }
+            def->data.emulator.profile.name = virXMLPropString(profile, "name");
             if (virXMLPropEnum(profile, "removeDisabled",
                                virDomainTPMProfileRemoveDisabledTypeFromString,
                                VIR_XML_PROP_NONZERO,
@@ -25139,16 +25137,23 @@ virDomainTPMDefFormat(virBuffer *buf,
                               virDomainTPMSourceTypeTypeToString(def->data.emulator.source_type));
             virBufferEscapeString(&backendChildBuf, " path='%s'/>\n", def->data.emulator.source_path);
         }
-        if (def->data.emulator.profile.source) {
+        if (def->data.emulator.profile.source ||
+            def->data.emulator.profile.name) {
             g_auto(virBuffer) profileAttrBuf = VIR_BUFFER_INITIALIZER;
 
-            virBufferAsprintf(&profileAttrBuf, " source='%s'",
-                              def->data.emulator.profile.source);
+            if (def->data.emulator.profile.source) {
+                virBufferAsprintf(&profileAttrBuf, " source='%s'",
+                                  def->data.emulator.profile.source);
+            }
             if (def->data.emulator.profile.removeDisabled) {
                virBufferAsprintf(&profileAttrBuf, " removeDisabled='%s'",
                                  virDomainTPMProfileRemoveDisabledTypeToString(def->data.emulator.profile.removeDisabled));
             }
 
+            if (def->data.emulator.profile.name) {
+                virBufferAsprintf(&profileAttrBuf, " name='%s'",
+                                  def->data.emulator.profile.name);
+            }
             virXMLFormatElement(&backendChildBuf, "profile", &profileAttrBuf, NULL);
         }
         break;

src/conf/domain_conf.h

@@ -1494,6 +1494,7 @@ struct _virDomainTPMEmulatorDef {
     virBitmap *activePcrBanks;
     struct {
         char *source; /* 'source' profile was created from */
+        char *name;   /* name read from active profile */
         virDomainTPMProfileRemoveDisabled removeDisabled;
     } profile;
 };

src/conf/schemas/domaincommon.rng

@@ -6061,9 +6061,11 @@
   <define name="tpm-backend-emulator-profile">
     <optional>
       <element name="profile">
-        <attribute name="source">
-          <ref name="profileName"/>
-        </attribute>
+        <optional>
+          <attribute name="source">
+            <ref name="profileName"/>
+          </attribute>
+        </optional>
         <optional>
           <attribute name="removeDisabled">
             <choice>
@@ -6072,6 +6074,11 @@
             </choice>
           </attribute>
         </optional>
+        <optional>
+          <attribute name="name">
+            <ref name="profileName"/>
+          </attribute>
+        </optional>
       </element>
     </optional>
   </define>

src/qemu/qemu_extdevice.c

@@ -175,6 +175,7 @@ qemuExtDevicesStart(virQEMUDriver *driver,
                     virDomainObj *vm,
                     bool incomingMigration)
 {
+    virDomainDef *persistentDef = vm->newDef;
     virDomainDef *def = vm->def;
     size_t i;
 
@@ -189,9 +190,11 @@ qemuExtDevicesStart(virQEMUDriver *driver,
 
     for (i = 0; i < def->ntpms; i++) {
         virDomainTPMDef *tpm = def->tpms[i];
+        virDomainTPMDef *persistentTPMDef = persistentDef->tpms[i];
 
         if (tpm->type == VIR_DOMAIN_TPM_TYPE_EMULATOR &&
-            qemuExtTPMStart(driver, vm, tpm, incomingMigration) < 0)
+            qemuExtTPMStart(driver, vm, tpm, persistentTPMDef,
+                            incomingMigration) < 0)
             return -1;
     }
 

src/qemu/qemu_tpm.c

@@ -628,15 +628,89 @@ qemuTPMVirCommandSwtpmAddTPMState(virCommand *cmd,
     }
 }
 
+/* qemuTPMEmulatorUpdateProfileName:
+ *
+ * @emulator: TPM emulator definition
+ * @persistentTPMDef: TPM definition from the persistent domain definition
+ * @cfg: virQEMUDriverConfig
+ * @saveDef: whether caller should save the persistent domain def
+ */
+static int
+qemuTPMEmulatorUpdateProfileName(virDomainTPMEmulatorDef *emulator,
+                                 virDomainTPMDef *persistentTPMDef,
+                                 const virQEMUDriverConfig *cfg,
+                                 bool *saveDef)
+{
+    g_autoptr(virJSONValue) object = NULL;
+    g_autofree char *stderr_buf = NULL;
+    g_autofree char *stdout_buf = NULL;
+    g_autoptr(virCommand) cmd = NULL;
+    g_autofree char *swtpm = NULL;
+    virJSONValue *active_profile;
+    const char *profile_name;
+    int exitstatus;
+
+    if (emulator->version != VIR_DOMAIN_TPM_VERSION_2_0 ||
+        !virTPMSwtpmCapsGet(VIR_TPM_SWTPM_FEATURE_CMDARG_PRINT_INFO))
+        return 0;
+
+    swtpm = virTPMGetSwtpm();
+    if (!swtpm)
+        return -1;
+
+    cmd = virCommandNew(swtpm);
+
+    virCommandSetUID(cmd, cfg->swtpm_user); /* should be uid of 'tss' or 'root' */
+    virCommandSetGID(cmd, cfg->swtpm_group);
+
+    virCommandAddArgList(cmd, "socket", "--print-info", "0x20", "--tpm2", NULL);
+
+    qemuTPMVirCommandSwtpmAddTPMState(cmd, emulator);
+
+    if (qemuTPMVirCommandSwtpmAddEncryption(cmd, emulator, swtpm) < 0)
+        return -1;
+
+    virCommandClearCaps(cmd);
+
+    virCommandSetOutputBuffer(cmd, &stdout_buf);
+    virCommandSetErrorBuffer(cmd, &stderr_buf);
+
+    if (virCommandRun(cmd, &exitstatus) < 0 || exitstatus != 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Could not run '%1$s --print-info'. exitstatus: %2$d; stderr: %3$s"),
+                          swtpm, exitstatus, stderr_buf);
+        return -1;
+    }
+
+    if (!(object = virJSONValueFromString(stdout_buf)))
+        return -1;
+
+    if (!(active_profile = virJSONValueObjectGetObject(object, "ActiveProfile")))
+        return -1;
+
+    profile_name = virJSONValueObjectGetString(active_profile, "Name");
+
+    g_free(emulator->profile.name);
+    emulator->profile.name = g_strdup(profile_name);
+
+    *saveDef = true;
+    g_free(persistentTPMDef->data.emulator.profile.name);
+    persistentTPMDef->data.emulator.profile.name = g_strdup(profile_name);
+
+    return 0;
+}
+
 /*
  * qemuTPMEmulatorBuildCommand:
  *
  * @tpm: TPM definition
+ * @persistentTPMDef: TPM definition from the persistent domain definition
  * @vmname: The name of the VM
  * @vmuuid: The UUID of the VM
  * @privileged: whether we are running in privileged mode
  * @cfg: virQEMUDriverConfig
  * @incomingMigration: whether we have an incoming migration
+ * @saveDef: whether caller should save the persistent domain def
  *
  * Create the virCommand use for starting the emulator
  * Do some initializations on the way, such as creation of storage
@@ -644,11 +718,13 @@ qemuTPMVirCommandSwtpmAddTPMState(virCommand *cmd,
  */
 static virCommand *
 qemuTPMEmulatorBuildCommand(virDomainTPMDef *tpm,
+                            virDomainTPMDef *persistentTPMDef,
                             const char *vmname,
                             const unsigned char *vmuuid,
                             bool privileged,
                             const virQEMUDriverConfig *cfg,
-                            bool incomingMigration)
+                            bool incomingMigration,
+                            bool *saveDef)
 {
     g_autoptr(virCommand) cmd = NULL;
     bool created = false;
@@ -697,6 +773,11 @@ qemuTPMEmulatorBuildCommand(virDomainTPMDef *tpm,
                                 incomingMigration) < 0)
         goto error;
 
+    if (run_setup && !incomingMigration &&
+        qemuTPMEmulatorUpdateProfileName(&tpm->data.emulator, persistentTPMDef,
+                                         cfg, saveDef) < 0)
+        goto error;
+
     if (!incomingMigration &&
         qemuTPMEmulatorReconfigure(&tpm->data.emulator, cfg, secretuuid) < 0)
         goto error;
@@ -996,6 +1077,7 @@ qemuExtTPMEmulatorSetupCgroup(const char *swtpmStateDir,
  * @driver: QEMU driver
  * @vm: the domain object
  * @tpm: TPM definition
+ * @persistentTPMDef: TPM definition from persistent domain definition
  * @shortName: short and unique name of the domain
  * @incomingMigration: whether we have an incoming migration
  *
@@ -1008,6 +1090,7 @@ qemuTPMEmulatorStart(virQEMUDriver *driver,
                      virDomainObj *vm,
                      const char *shortName,
                      virDomainTPMDef *tpm,
+                     virDomainTPMDef *persistentTPMDef,
                      bool incomingMigration)
 {
     g_autoptr(virCommand) cmd = NULL;
@@ -1016,6 +1099,7 @@ qemuTPMEmulatorStart(virQEMUDriver *driver,
     g_autofree char *pidfile = NULL;
     virTimeBackOffVar timebackoff;
     const unsigned long long timeout = 1000; /* ms */
+    bool saveDef = false;
     pid_t pid = -1;
     bool lockMetadataException = false;
 
@@ -1024,12 +1108,18 @@ qemuTPMEmulatorStart(virQEMUDriver *driver,
     /* stop any left-over TPM emulator for this VM */
     qemuTPMEmulatorStop(cfg->swtpmStateDir, shortName);
 
-    if (!(cmd = qemuTPMEmulatorBuildCommand(tpm, vm->def->name, vm->def->uuid,
+    if (!(cmd = qemuTPMEmulatorBuildCommand(tpm, persistentTPMDef,
+                                            vm->def->name, vm->def->uuid,
                                             driver->privileged,
                                             cfg,
-                                            incomingMigration)))
+                                            incomingMigration,
+                                            &saveDef)))
         return -1;
 
+    if (saveDef &&
+        virDomainDefSave(vm->newDef, driver->xmlopt, cfg->configDir) < 0)
+        goto error;
+
     if (qemuExtDeviceLogCommand(driver, vm, cmd, "TPM Emulator") < 0)
         return -1;
 
@@ -1213,6 +1303,7 @@ int
 qemuExtTPMStart(virQEMUDriver *driver,
                 virDomainObj *vm,
                 virDomainTPMDef *tpm,
+                virDomainTPMDef *persistentTPMDef,
                 bool incomingMigration)
 {
     g_autofree char *shortName = virDomainDefGetShortName(vm->def);
@@ -1220,7 +1311,8 @@ qemuExtTPMStart(virQEMUDriver *driver,
     if (!shortName)
         return -1;
 
-    return qemuTPMEmulatorStart(driver, vm, shortName, tpm, incomingMigration);
+    return qemuTPMEmulatorStart(driver, vm, shortName, tpm, persistentTPMDef,
+                                incomingMigration);
 }
 
 

src/qemu/qemu_tpm.h

@@ -44,9 +44,10 @@ void qemuExtTPMCleanupHost(virQEMUDriver *driver,
 int qemuExtTPMStart(virQEMUDriver *driver,
                     virDomainObj *vm,
                     virDomainTPMDef *def,
+                    virDomainTPMDef *persistentDefTPM,
                     bool incomingMigration)
     ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2)
-    ATTRIBUTE_NONNULL(3)
+    ATTRIBUTE_NONNULL(3) ATTRIBUTE_NONNULL(4)
     G_GNUC_WARN_UNUSED_RESULT;
 
 void qemuExtTPMStop(virQEMUDriver *driver,

src/util/virtpm.c

@@ -42,6 +42,7 @@ VIR_ENUM_IMPL(virTPMSwtpmFeature,
               "cmdarg-migration",
               "nvram-backend-dir",
               "nvram-backend-file",
+              "cmdarg-print-info",
 );
 
 VIR_ENUM_IMPL(virTPMSwtpmSetupFeature,

src/util/virtpm.h

@@ -33,6 +33,7 @@ typedef enum {
     VIR_TPM_SWTPM_FEATURE_CMDARG_MIGRATION,
     VIR_TPM_SWTPM_FEATURE_NVRAM_BACKEND_DIR,
     VIR_TPM_SWTPM_FEATURE_NVRAM_BACKEND_FILE,
+    VIR_TPM_SWTPM_FEATURE_CMDARG_PRINT_INFO,
 
     VIR_TPM_SWTPM_FEATURE_LAST
 } virTPMSwtpmFeature;

tests/qemuxmlconfdata/tpm-emulator-crb-profile.xml

@@ -29,7 +29,7 @@
     <input type='keyboard' bus='ps2'/>
     <tpm model='tpm-crb'>
       <backend type='emulator' version='2.0'>
-        <profile source='local:restricted' removeDisabled='check'/>
+        <profile source='local:restricted' removeDisabled='check' name='custom:restricted'/>
       </backend>
     </tpm>
     <audio id='1' type='none'/>