From: Michal Privoznik <mprivozn@redhat.com>
Date: Fri, 20 Jan 2017 09:06:39 +0000 (+0100)
Subject: qemuSecurityRestoreAllLabel: Don't use transactions
X-Git-Tag: CVE-2017-2635~185
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3e6839d4e801cdcc9d49cd9e4bf83a3694b2a273;p=thirdparty%2Flibvirt.git

qemuSecurityRestoreAllLabel: Don't use transactions

Because of the nature of security driver transactions, it is
impossible to use them properly. The thing is, transactions enter
the domain namespace and commit all the seclabel changes.
However, in RestoreAllLabel() this is impossible - the qemu
process, the only process running in the namespace, is gone. And
thus is the namespace. Therefore we shouldn't use the transactions
as there is no namespace to enter.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
---

diff --git a/src/qemu/qemu_security.c b/src/qemu/qemu_security.c
index 544feeb4ae..13d99cdbd4 100644
--- a/src/qemu/qemu_security.c
+++ b/src/qemu/qemu_security.c
@@ -73,22 +73,15 @@ qemuSecurityRestoreAllLabel(virQEMUDriverPtr driver,
                             virDomainObjPtr vm,
                             bool migrated)
 {
-    if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT) &&
-        virSecurityManagerTransactionStart(driver->securityManager) < 0)
-        goto cleanup;
-
-    if (virSecurityManagerRestoreAllLabel(driver->securityManager,
-                                          vm->def,
-                                          migrated) < 0)
-        goto cleanup;
-
-    if (qemuDomainNamespaceEnabled(vm, QEMU_DOMAIN_NS_MOUNT) &&
-        virSecurityManagerTransactionCommit(driver->securityManager,
-                                            vm->pid) < 0)
-        goto cleanup;
-
- cleanup:
-    virSecurityManagerTransactionAbort(driver->securityManager);
+    /* In contrast to qemuSecuritySetAllLabel, do not use
+     * secdriver transactions here. This function is called from
+     * qemuProcessStop() which is meant to do cleanup after qemu
+     * process died. If it did do, the namespace is gone as qemu
+     * was the only process running there. We would not succeed
+     * in entering the namespace then. */
+    virSecurityManagerRestoreAllLabel(driver->securityManager,
+                                      vm->def,
+                                      migrated);
 }