[PATCH] lxc: Add TPM passthrough option for LXC driver

[Julio Faracco]

There is no support to use TPM for passthrough for LXC libvirt driver
this commit adds the option to use host TPM inside containers.

Signed-off-by: Julio Faracco <jcfaracco at gmail.com>
---
 src/lxc/lxc_cgroup.c     | 27 +++++++++++++++++++
 src/lxc/lxc_controller.c | 56 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+)

diff --git a/src/lxc/lxc_cgroup.c b/src/lxc/lxc_cgroup.c
index d13f2adde5..955d2b4fc1 100644
--- a/src/lxc/lxc_cgroup.c
+++ b/src/lxc/lxc_cgroup.c
@@ -374,6 +374,33 @@ static int virLXCCgroupSetupDeviceACL(virDomainDefPtr def,
             return -1;
     }
 
+    for (i = 0; i < def->ntpms; i++) {
+        virDomainTPMDefPtr tpm = def->tpms[i];
+        const char *dev = NULL;
+
+        switch (tpm->type) {
+        case VIR_DOMAIN_TPM_TYPE_EMULATOR:
+        case VIR_DOMAIN_TPM_TYPE_LAST:
+            break;
+        case VIR_DOMAIN_TPM_TYPE_PASSTHROUGH:
+            dev = "/dev/tpm0";
+            break;
+        }
+
+        if (!dev)
+            continue;
+
+        if (!virFileExists(dev)) {
+            VIR_DEBUG("Ignoring non-existent device %s", dev);
+            continue;
+        }
+
+        if (virCgroupAllowDevicePath(cgroup, dev,
+                                     VIR_CGROUP_DEVICE_READ,
+                                     false) < 0)
+            return -1;
+    }
+
     VIR_DEBUG("Device ACL setup complete");
 
     return 0;
diff --git a/src/lxc/lxc_controller.c b/src/lxc/lxc_controller.c
index ae6b737b60..70ca773bbf 100644
--- a/src/lxc/lxc_controller.c
+++ b/src/lxc/lxc_controller.c
@@ -1644,6 +1644,59 @@ virLXCControllerSetupHostdevSubsysUSB(virDomainDefPtr vmDef,
 }
 
 
+static int
+virLXCControllerSetupTPM(virLXCControllerPtr ctrl)
+{
+    virDomainDefPtr def = ctrl->def;
+    size_t i;
+
+    for (i = 0; i < def->ntpms; i++) {
+        virDomainTPMDefPtr tpm = def->tpms[i];
+        g_autofree char *path = NULL;
+        const char *tpm_dev = NULL;
+        struct stat sb;
+        dev_t dev;
+
+        switch (tpm->type) {
+        case VIR_DOMAIN_TPM_TYPE_EMULATOR:
+        case VIR_DOMAIN_TPM_TYPE_LAST:
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("unsupported timer type (name) '%s'"),
+                           virDomainTPMBackendTypeToString(tpm->type));
+            return -1;
+        case VIR_DOMAIN_TPM_TYPE_PASSTHROUGH:
+            tpm_dev = "/dev/tpm0";
+            path = g_strdup_printf("/%s/%s.dev/%s", LXC_STATE_DIR,
+                                   def->name, "/rtc");
+            break;
+        }
+
+        if (!tpm_dev)
+            continue;
+
+        if (stat(tpm_dev, &sb) < 0) {
+            virReportSystemError(errno, _("Unable to access %s"),
+                                 tpm_dev);
+            return -1;
+        }
+
+        dev = makedev(major(sb.st_rdev), minor(sb.st_rdev));
+        if (mknod(path, S_IFCHR, dev) < 0 ||
+            chmod(path, sb.st_mode)) {
+            virReportSystemError(errno,
+                                 _("Failed to make device %s"),
+                                 path);
+            return -1;
+        }
+
+        if (lxcContainerChown(def, path) < 0)
+            return -1;
+    }
+
+    return 0;
+}
+
+
 static int
 virLXCControllerSetupHostdevCapsStorage(virDomainDefPtr vmDef,
                                         virDomainHostdevDefPtr def,
@@ -2358,6 +2411,9 @@ virLXCControllerRun(virLXCControllerPtr ctrl)
     if (virLXCControllerSetupAllHostdevs(ctrl) < 0)
         goto cleanup;
 
+    if (virLXCControllerSetupTPM(ctrl) < 0)
+        goto cleanup;
+
     if (virLXCControllerSetupFuse(ctrl) < 0)
         goto cleanup;
 
-- 
2.25.1