[libvirt] [PATCH 1/2] nvram: Fix permissions

[Michal Privoznik]

I've noticed two problem with the automatically created NVRAM varstore
file. The first, even though I run qemu as root:root for some reason I
get Permission denied when trying to open the _VARS.fd file. The
problem is, the upper directory misses execute permissions, which in
combination with us dropping some capabilities result in EPERM.

The next thing is, that if I switch SELinux to enforcing mode, I get
another EPERM because the vars file is not labeled correctly. It is
passed to qemu as disk and hence should be labelled as disk. QEMU may
write to it eventually, so this is different to kernel or initrd.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 libvirt.spec.in                 | 2 +-
 src/security/security_selinux.c | 5 ++++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/libvirt.spec.in b/libvirt.spec.in
index a6a58cf..ecf160b 100644
--- a/libvirt.spec.in
+++ b/libvirt.spec.in
@@ -1938,7 +1938,7 @@ exit 0
 %dir %attr(0750, %{qemu_user}, %{qemu_group}) %{_localstatedir}/lib/libvirt/qemu/
 %dir %attr(0750, %{qemu_user}, %{qemu_group}) %{_localstatedir}/lib/libvirt/qemu/channel/
 %dir %attr(0750, %{qemu_user}, %{qemu_group}) %{_localstatedir}/lib/libvirt/qemu/channel/target/
-%dir %attr(0750, %{qemu_user}, %{qemu_group}) %{_localstatedir}/lib/libvirt/qemu/nvram/
+%dir %attr(0711, %{qemu_user}, %{qemu_group}) %{_localstatedir}/lib/libvirt/qemu/nvram/
 %dir %attr(0750, %{qemu_user}, %{qemu_group}) %{_localstatedir}/cache/libvirt/qemu/
 %{_datadir}/augeas/lenses/libvirtd_qemu.aug
 %{_datadir}/augeas/lenses/tests/test_libvirtd_qemu.aug
diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
index bf67fb5..3db2b27 100644
--- a/src/security/security_selinux.c
+++ b/src/security/security_selinux.c
@@ -2300,8 +2300,11 @@ virSecuritySELinuxSetSecurityAllLabel(virSecurityManagerPtr mgr,
                                      mgr) < 0)
         return -1;
 
+    /* This is different than kernel or initrd. The nvram store
+     * is really a disk, qemu can read and write to it. */
     if (def->os.loader && def->os.loader->nvram &&
-        virSecuritySELinuxSetFilecon(def->os.loader->nvram, data->content_context) < 0)
+        secdef && secdef->imagelabel &&
+        virSecuritySELinuxSetFilecon(def->os.loader->nvram, secdef->imagelabel) < 0)
         return -1;
 
     if (def->os.kernel &&
-- 
1.8.5.5