qemu: Label restore path outside of secdriver transactions

As explained in the previous commit, we need to relabel the file
we are restoring the domain from. That is the FD that is passed
to QEMU. If the file is not under /dev then the file inside the
namespace is the very same as the one in the host. And regardless
of using transactions, the file will be relabeled. But, if the
file is under /dev then when using transactions only the copy
inside the namespace is relabeled and the one in the host is not.
But QEMU is reading from the one in the host, actually.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1772838

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>

diff --git a/src/qemu/qemu_security.c b/src/qemu/qemu_security.c
index 484fc345525f8b9d87537bd47deddd8022ebd463..61b9e4f0e3ddeab34bcbbfd96c2f601608d15af7 100644 (file)
--- a/src/qemu/qemu_security.c
+++ b/src/qemu/qemu_security.c
@@ -39,6 +39,13 @@ qemuSecuritySetAllLabel(virQEMUDriverPtr driver,
     qemuDomainObjPrivatePtr priv = vm->privateData;
     pid_t pid = -1;
 
+    /* Explicitly run this outside of transaction. We really want to relabel
+     * the file in the host and not in the domain's namespace. */
+    if (virSecurityManagerDomainSetPathLabelRO(driver->securityManager,
+                                               vm->def,
+                                               stdin_path) < 0)
+        goto cleanup;
+
     if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT))
         pid = vm->pid;
 

diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
index 8aeb6e45a5e95efd6e3e0bd99504bd297e20bc15..281c303296ad254e4ff64d4a03ec84168bae5437 100644 (file)
--- a/src/security/security_selinux.c
+++ b/src/security/security_selinux.c
@@ -3135,7 +3135,7 @@ virSecuritySELinuxSetSecuritySmartcardCallback(virDomainDefPtr def,
 static int
 virSecuritySELinuxSetAllLabel(virSecurityManagerPtr mgr,
                               virDomainDefPtr def,
-                              const char *stdin_path,
+                              const char *stdin_path G_GNUC_UNUSED,
                               bool chardevStdioLogd,
                               bool migrated G_GNUC_UNUSED)
 {
@@ -3231,11 +3231,6 @@ virSecuritySELinuxSetAllLabel(virSecurityManagerPtr mgr,
                                      data->content_context, true) < 0)
         return -1;
 
-    if (stdin_path &&
-        virSecuritySELinuxSetFilecon(mgr, stdin_path,
-                                     data->content_context, true) < 0)
-        return -1;
-
     return 0;
 }
 
@@ -3393,6 +3388,21 @@ virSecuritySELinuxDomainSetPathLabel(virSecurityManagerPtr mgr,
     return virSecuritySELinuxSetFilecon(mgr, path, seclabel->imagelabel, true);
 }
 
+static int
+virSecuritySELinuxDomainSetPathLabelRO(virSecurityManagerPtr mgr,
+                                       virDomainDefPtr def,
+                                       const char *path)
+{
+    virSecuritySELinuxDataPtr data = virSecurityManagerGetPrivateData(mgr);
+    virSecurityLabelDefPtr secdef;
+
+    secdef = virDomainDefGetSecurityLabelDef(def, SECURITY_SELINUX_NAME);
+
+    if (!path || !secdef || !secdef->relabel || data->skipAllLabel)
+        return 0;
+
+    return virSecuritySELinuxSetFilecon(mgr, path, data->content_context, false);
+}
 
 /*
  * virSecuritySELinuxSetFileLabels:
@@ -3596,6 +3606,7 @@ virSecurityDriver virSecurityDriverSELinux = {
     .getBaseLabel                       = virSecuritySELinuxGetBaseLabel,
 
     .domainSetPathLabel                 = virSecuritySELinuxDomainSetPathLabel,
+    .domainSetPathLabelRO               = virSecuritySELinuxDomainSetPathLabelRO,
 
     .domainSetSecurityChardevLabel      = virSecuritySELinuxSetChardevLabel,
     .domainRestoreSecurityChardevLabel  = virSecuritySELinuxRestoreChardevLabel,