Re: [libvirt] [PATCH 06/12] qemu: Extend QEMU with external TPM support

Implement functions for managing the storage of the external swtpm as well as starting and stopping it. Also implement functions to use swtpm_setup, which simulates the manufacturing of a TPM, which includes creation of certificates for the device. Further, the external TPM needs storage on the host that we need to set up before it can be run. We can clean up the host once the domain is undefined. This patch also implements a small layer for external device support that calls into the TPM device layer if a domain has an attached TPM. This is the layer we will wire up later on.

Signed-off-by: Stefan Berger <stefanb(a)linux.vnet.ibm.com&gt; Reviewed-by: John Ferlan <jferlan(a)redhat.com&gt; --- src/qemu/Makefile.inc.am | 4 + src/qemu/qemu_domain.c | 2 + src/qemu/qemu_extdevice.c | 154 ++++++++++ src/qemu/qemu_extdevice.h | 53 ++++ src/qemu/qemu_process.c | 12 + src/qemu/qemu_tpm.c | 751 ++++++++++++++++++++++++++++++++++++++++++++++ src/qemu/qemu_tpm.h | 50 +++ 7 files changed, 1026 insertions(+) create mode 100644 src/qemu/qemu_extdevice.c create mode 100644 src/qemu/qemu_extdevice.h create mode 100644 src/qemu/qemu_tpm.c create mode 100644 src/qemu/qemu_tpm.h

+/* + * virtTPMGetTPMStorageDir: + * + * @storagepath: directory for swtpm's persistent state + * + * Derive the 'TPMStorageDir' from the storagepath by searching + * for the last '/'. + */ +static char * +qemuTPMGetTPMStorageDir(const char *storagepath) +{ + const char *tail = strrchr(storagepath, '/'); + char *path = NULL; + + if (!tail) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Could not get tail of storagedir %s"), + storagepath); + return NULL; + } + ignore_value(VIR_STRNDUP(path, storagepath, tail - storagepath)); + + return path; +}

+/* + * qemuTPMCreateEmulatorStorage + * + * @storagepath: directory for swtpm's persistent state + * @created: a pointer to a bool that will be set to true if the + * storage was created because it did not exist yet

+ * @swtpm_user: The uid that needs to be able to access the directory + * @swtpm_group: The gid that needs to be able to access the directory + * + * Unless the storage path for the swtpm for the given VM + * already exists, create it and make it accessible for the given userid. + * Adapt ownership of the directory and all swtpm's state files there. + */

+static int +qemuTPMEmulatorPrepareHost(virDomainTPMDefPtr tpm, + const char *logDir, + const char *vmname, + uid_t swtpm_user, + gid_t swtpm_group, + const char *swtpmStateDir, + uid_t qemu_user, + const char *shortName) +{ + int ret = -1; + + if (qemuTPMEmulatorInit() < 0) + return -1; + + /* create log dir ... allow 'tss' user to cd into it */ + if (virFileMakePathWithMode(logDir, 0711) < 0) + return -1; + + /* ... and adjust ownership */ + if (virDirCreate(logDir, 0730, swtpm_user, swtpm_group, + VIR_DIR_CREATE_ALLOW_EXIST) < 0) + goto cleanup; + + /* create logfile name ... */ + if (!tpm->data.emulator.logfile && + virAsprintf(&tpm->data.emulator.logfile, "%s/%s-swtpm.log", + logDir, vmname) < 0)

+ goto cleanup; + + /* ... and make sure it can be accessed by swtpm_user */ + if (virFileExists(tpm->data.emulator.logfile) && + chown(tpm->data.emulator.logfile, swtpm_user, swtpm_group) < 0) { + virReportSystemError(errno, + _("Could not chown on swtpm logfile %s"), + tpm->data.emulator.logfile); + goto cleanup; + } + + /* + create our swtpm state dir ... + - QEMU user needs to be able to access the socket there + - swtpm group needs to be able to create files there + - in privileged mode 0570 would be enough, for non-privileged mode + we need 0770 + */ + if (virDirCreate(swtpmStateDir, 0770, qemu_user, swtpm_group, + VIR_DIR_CREATE_ALLOW_EXIST) < 0) + goto cleanup; + + /* create the socket filename */ + if (!tpm->data.emulator.source.data.nix.path && + !(tpm->data.emulator.source.data.nix.path = + qemuTPMCreateEmulatorSocket(swtpmStateDir, shortName))) + goto cleanup; + tpm->data.emulator.source.type = VIR_DOMAIN_CHR_TYPE_UNIX; + + ret = 0; + + cleanup: + + return ret; +} +

+static int +qemuExtTPMStartEmulator(virQEMUDriverPtr driver, + virDomainDefPtr def, + qemuDomainLogContextPtr logCtxt) +{ + int ret = -1; + virCommandPtr cmd = NULL; + int exitstatus; + char *errbuf = NULL; + virQEMUDriverConfigPtr cfg; + virDomainTPMDefPtr tpm = def->tpm; + char *shortName = virDomainDefGetShortName(def); + + if (!shortName) + return -1; + + cfg = virQEMUDriverGetConfig(driver); + + /* stop any left-over TPM emulator for this VM */ + qemuTPMEmulatorStop(cfg->swtpmStateDir, shortName); + + if (!(cmd = qemuTPMEmulatorBuildCommand(tpm, def->name, def->uuid, + driver->privileged, + cfg->swtpm_user, + cfg->swtpm_group))) + goto cleanup; + + if (qemuExtDeviceLogCommand(logCtxt, cmd, "TPM Emulator") < 0) + goto cleanup; + + virCommandSetErrorBuffer(cmd, &errbuf); + + if (virCommandRun(cmd, &exitstatus) < 0 || exitstatus != 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Could not start 'swtpm'. exitstatus: %d, " + "error: %s"), exitstatus, errbuf);

+ goto cleanup; + } + + ret = 0; +