Re: [PATCH v2 2/2] qemu: tpm: Extend TPM domain XML with PCR banks to activate

Hi On Mon, Nov 1, 2021 at 9:23 PM Stefan Berger <stefanb(a)linux.ibm.com&gt; wrote: > Extend the TPM domain XML with an attribute active_pcr_banks that allows > a user to specify the PCR banks to activate before starting a VM. A comma- > separated list of PCR banks with the choices of sha1, sha256, sha384 and > sha512 is allowed. When the XML attribute is provided, the set of active > PCR banks is 'enforced' by running swtpm_setup before every start of the > VM. The activation requires that swtpm_setup v0.7 or later is installed > and may not have any effect otherwise. > Is this a configuration switch that the guest is expected to handle in general?

On real hw (or ftpm), is there some bios option or equivalent to configure the pcr banks?

If not, shouldn't this be a first-time only configuration? (and attempts to change the value further be rejected by libvirt)

> <tpm model='tpm-tis'> > <backend type='emulator' version='2.0' active_pcr_banks='sha256,sha384'/> > </tpm> > > Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=2016599 > > Signed-off-by: Stefan Berger <stefanb(a)linux.ibm.com&gt; > --- > docs/formatdomain.rst | 12 ++- > docs/schemas/basictypes.rng | 6 ++ > docs/schemas/domaincommon.rng | 5 ++ > src/conf/domain_conf.c | 21 ++++- > src/conf/domain_conf.h | 1 + > src/qemu/qemu_tpm.c | 80 +++++++++++++++++++ > src/util/virtpm.c | 1 + > src/util/virtpm.h | 1 + > tests/qemuxml2argvdata/tpm-emulator-tpm2.xml | 2 +- > .../tpm-emulator-tpm2.x86_64-latest.xml | 2 +- > 10 files changed, 127 insertions(+), 4 deletions(-) > > diff --git a/docs/formatdomain.rst b/docs/formatdomain.rst > index 0651975c88..8785a7a682 100644 > --- a/docs/formatdomain.rst > +++ b/docs/formatdomain.rst > @@ -7537,7 +7537,7 @@ Example: usage of the TPM Emulator > ... > <devices> > <tpm model='tpm-tis'> > - <backend type='emulator' version='2.0'> > + <backend type='emulator' version='2.0' active_pcr_banks='sha256'> > <encryption secret='6dd3e4a5-1d76-44ce-961f-f119f5aad935'/> > </backend> > </tpm> > @@ -7598,6 +7598,16 @@ Example: usage of the TPM Emulator > This attribute only works with the ``emulator`` backend. The accepted values > are ``yes`` and ``no``. :since:`Since 7.0.0` > > +``active_pcr_banks`` > + The ``active_pcr_banks`` attribute indicates the names of the PCR banks > + of a TPM 2.0 to activate. A comma separated list of PCR banks' names > + must be provided. Valid names are for example sha1, sha256, sha384, and > + sha512. If this attribute is provided, the set of PCR banks are activated > + before every start of a VM and this step is logged in the swtpm's log. > + This attribute requires that swtpm_setup v0.7 or later is installed > + and may not have any effect otherwise. This attribute only works with the > + ``emulator`` backend. since:`Since 7.10.0` > + > ``encryption`` > The ``encryption`` element allows the state of a TPM emulator to be > encrypted. The ``secret`` must reference a secret object that holds the > diff --git a/docs/schemas/basictypes.rng b/docs/schemas/basictypes.rng > index a221ff6295..3bd1eebdc4 100644 > --- a/docs/schemas/basictypes.rng > +++ b/docs/schemas/basictypes.rng > @@ -88,6 +88,12 @@ > </choice> > </define> > > + <define name="pcrBankList"> > + <data type="string"> > + <param name="pattern">(sha1|sha256|sha384|sha512){1}(,(sha1|sha256|sha384|sha512)){0,3}</param> > + </data> > + </define> > + > <define name="numaDistanceValue"> > <data type="unsignedInt"> > <param name="minInclusive">10</param> > diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng > index 67df13d90d..6801673cf1 100644 > --- a/docs/schemas/domaincommon.rng > +++ b/docs/schemas/domaincommon.rng > @@ -5331,6 +5331,11 @@ > </choice> > </attribute> > </optional> > + <optional> > + <attribute name="active_pcr_banks"> > + <ref name="pcrBankList"/> > + </attribute> > + </optional> > </group> > </choice> > <optional> > diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c > index 4644d18120..bc8237fd0b 100644 > --- a/src/conf/domain_conf.c > +++ b/src/conf/domain_conf.c > @@ -3207,6 +3207,7 @@ void virDomainTPMDefFree(virDomainTPMDef *def) > break; > case VIR_DOMAIN_TPM_TYPE_EMULATOR: > virDomainChrSourceDefClear(&def->data.emulator.source); > + g_free(def->data.emulator.activePcrBanks); > g_free(def->data.emulator.storagepath); > g_free(def->data.emulator.logfile); > break; > @@ -11733,7 +11734,7 @@ virDomainSmartcardDefParseXML(virDomainXMLOption *xmlopt, > * Emulator state encryption is supported with the following: > * > * <tpm model='tpm-tis'> > - * <backend type='emulator' version='2.0'> > + * <backend type='emulator' version='2.0' active_pcr_banks='sha256,sha384'> > * <encryption secret='32ee7e76-2178-47a1-ab7b-269e6e348015'/> > * </backend> > * </tpm> > @@ -11759,6 +11760,7 @@ virDomainTPMDefParseXML(virDomainXMLOption *xmlopt, > g_autofree char *version = NULL; > g_autofree char *secretuuid = NULL; > g_autofree char *persistent_state = NULL; > + g_autofree char *activePcrBanks = NULL; > g_autofree xmlNodePtr *backends = NULL; > > def = g_new0(virDomainTPMDef, 1); > @@ -11841,6 +11843,18 @@ virDomainTPMDefParseXML(virDomainXMLOption *xmlopt, > goto error; > } > } > + if (def->version == VIR_DOMAIN_TPM_VERSION_2_0) { > + activePcrBanks = virXMLPropString(backends[0], "active_pcr_banks"); > + if (activePcrBanks) { > + if (!virStringMatch(activePcrBanks, > + "(sha1|sha256|sha384|sha512)(,(sha1|sha256|sha384|sha512)){0,3}")) { > + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", > + _("Malformatted list of PCR banks")); > + goto error; > + } > + def->data.emulator.activePcrBanks = g_steal_pointer(&activePcrBanks); > + } > + } > break; > case VIR_DOMAIN_TPM_TYPE_LAST: > goto error; > @@ -25433,6 +25447,11 @@ virDomainTPMDefFormat(virBuffer *buf, > virDomainTPMVersionTypeToString(def->version)); > if (def->data.emulator.persistent_state) > virBufferAddLit(buf, " persistent_state='yes'"); > + if (def->version == VIR_DOMAIN_TPM_VERSION_2_0 && > + def->data.emulator.activePcrBanks) { > + virBufferAsprintf(buf, " active_pcr_banks='%s'", > + def->data.emulator.activePcrBanks); > + } > if (def->data.emulator.hassecretuuid) { > char uuidstr[VIR_UUID_STRING_BUFLEN]; > virBufferAddLit(buf, ">\n"); > diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h > index cb6d8975b8..19597dba7e 100644 > --- a/src/conf/domain_conf.h > +++ b/src/conf/domain_conf.h > @@ -1381,6 +1381,7 @@ struct _virDomainTPMDef { > unsigned char secretuuid[VIR_UUID_BUFLEN]; > bool hassecretuuid; > bool persistent_state; > + char *activePcrBanks; > } emulator; > } data; > }; > diff --git a/src/qemu/qemu_tpm.c b/src/qemu/qemu_tpm.c > index 93cb04f49d..bb14228edc 100644 > --- a/src/qemu/qemu_tpm.c > +++ b/src/qemu/qemu_tpm.c > @@ -566,6 +566,78 @@ qemuTPMEmulatorRunSetup(const char *storagepath, > } > > > +/* > + * qemuTPMEmulatorReconfigure > + * > + * > + * @storagepath: path to the directory for TPM state > + * @swtpm_user: The userid to switch to when setting up the TPM; > + * typically this should be the uid of 'tss' or 'root' > + * @swtpm_group: The group id to switch to > + * @swtpmActivePcrBanks: The string describing the active PCR banks > + * @logfile: The file to write the log into; it must be writable > + * for the user given by userid or 'tss' > + * @tpmversion: The version of the TPM, either a TPM 1.2 or TPM 2 > + * @secretuuid: The secret's UUID needed for state encryption > + * > + * Reconfigure the active PCR banks of a TPM 2. > + */ > +static int > +qemuTPMEmulatorReconfigure(const char *storagepath, > + uid_t swtpm_user, > + gid_t swtpm_group, > + const char *swtpmActivePcrBanks, > + const char *logfile, > + const virDomainTPMVersion tpmversion, > + const unsigned char *secretuuid) > +{ > + g_autoptr(virCommand) cmd = NULL; > + int exitstatus; > + g_autofree char *swtpm_setup = virTPMGetSwtpmSetup(); > + VIR_AUTOCLOSE pwdfile_fd = -1; > + > + if (!swtpm_setup) > + return -1; > + > + if (tpmversion != VIR_DOMAIN_TPM_VERSION_2_0 || > + swtpmActivePcrBanks == NULL || > + !virTPMSwtpmSetupCapsGet( > + VIR_TPM_SWTPM_SETUP_FEATURE_CMDARG_RECONFIGURE_PCR_BANKS)) > + return 0; > + > + cmd = virCommandNew(swtpm_setup); > + if (!cmd) > + return -1; > + > + virCommandSetUID(cmd, swtpm_user); > + virCommandSetGID(cmd, swtpm_group); > + > + virCommandAddArgList(cmd, "--tpm2", NULL); > + > + if (qemuTPMVirCommandAddEncryption(cmd, swtpm_setup, secretuuid) < 0) > + return -1; > + > + virCommandAddArgList(cmd, > + "--tpm-state", storagepath, > + "--logfile", logfile, > + "--pcr-banks", swtpmActivePcrBanks, > + "--reconfigure", > + NULL); > + > + virCommandClearCaps(cmd); > + > + if (virCommandRun(cmd, &exitstatus) < 0 || exitstatus != 0) { > + virReportError(VIR_ERR_INTERNAL_ERROR, > + _("Could not run '%s --reconfigure'. exitstatus: %d; " > + "Check error log '%s' for details."), > + swtpm_setup, exitstatus, logfile); > + return -1; > + } > + > + return 0; > +} > + > + > /* > * qemuTPMEmulatorBuildCommand: > * > @@ -620,6 +692,14 @@ qemuTPMEmulatorBuildCommand(virDomainTPMDef *tpm, > secretuuid, incomingMigration) < 0) > goto error; > > + if (!incomingMigration && > + qemuTPMEmulatorReconfigure(tpm->data.emulator.storagepath, > + swtpm_user, swtpm_group, > + tpm->data.emulator.activePcrBanks, > + tpm->data.emulator.logfile, tpm->version, > + secretuuid) < 0) > + goto error; > + > unlink(tpm->data.emulator.source.data.nix.path); > > cmd = virCommandNew(swtpm); > diff --git a/src/util/virtpm.c b/src/util/virtpm.c > index 40d9272e66..7fa870b803 100644 > --- a/src/util/virtpm.c > +++ b/src/util/virtpm.c > @@ -47,6 +47,7 @@ VIR_ENUM_IMPL(virTPMSwtpmSetupFeature, > "cmdarg-pwdfile-fd", > "cmdarg-create-config-files", > "tpm12-not-need-root", > + "cmdarg-reconfigure-pcr-banks", > ); > > /** > diff --git a/src/util/virtpm.h b/src/util/virtpm.h > index b75eb84f31..defea6c106 100644 > --- a/src/util/virtpm.h > +++ b/src/util/virtpm.h > @@ -40,6 +40,7 @@ typedef enum { > VIR_TPM_SWTPM_SETUP_FEATURE_CMDARG_PWDFILE_FD, > VIR_TPM_SWTPM_SETUP_FEATURE_CMDARG_CREATE_CONFIG_FILES, > VIR_TPM_SWTPM_SETUP_FEATURE_TPM12_NOT_NEED_ROOT, > + VIR_TPM_SWTPM_SETUP_FEATURE_CMDARG_RECONFIGURE_PCR_BANKS, > > VIR_TPM_SWTPM_SETUP_FEATURE_LAST > } virTPMSwtpmSetupFeature; > diff --git a/tests/qemuxml2argvdata/tpm-emulator-tpm2.xml b/tests/qemuxml2argvdata/tpm-emulator-tpm2.xml > index 3e2f485ee7..ca9b38540d 100644 > --- a/tests/qemuxml2argvdata/tpm-emulator-tpm2.xml > +++ b/tests/qemuxml2argvdata/tpm-emulator-tpm2.xml > @@ -23,7 +23,7 @@ > <input type='mouse' bus='ps2'/> > <input type='keyboard' bus='ps2'/> > <tpm model='tpm-tis'> > - <backend type='emulator' version='2.0'/> > + <backend type='emulator' version='2.0' active_pcr_banks='sha256,sha512'/> > </tpm> > <memballoon model='virtio'/> > </devices> > diff --git a/tests/qemuxml2xmloutdata/tpm-emulator-tpm2.x86_64-latest.xml b/tests/qemuxml2xmloutdata/tpm-emulator-tpm2.x86_64-latest.xml > index fe4e1aba19..2488f6ad29 100644 > --- a/tests/qemuxml2xmloutdata/tpm-emulator-tpm2.x86_64-latest.xml > +++ b/tests/qemuxml2xmloutdata/tpm-emulator-tpm2.x86_64-latest.xml > @@ -28,7 +28,7 @@ > <input type='mouse' bus='ps2'/> > <input type='keyboard' bus='ps2'/> > <tpm model='tpm-tis'> > - <backend type='emulator' version='2.0'/> > + <backend type='emulator' version='2.0' active_pcr_banks='sha256,sha512'/> > </tpm> > <audio id='1' type='none'/> > <memballoon model='virtio'> > -- > 2.31.1 > lgtm otherwise