[libvirt] [PATCH] Fix crash in SELinuxSecurityVerify

[Laine Stump]

When attempting to edit a domain, libvirtd segfaulted in
SELinuxSecurityVerify() on this line:

  if (!STREQ(virSecurityManagerGetModel(mgr), secdef->model)) {

because secdef->model was NULL. Although I'm too tired to investigate
in depth, I noticed that all the other functions in that file that do
the same STREQ() will first check that def->seclabel.label is
non-NULL, but this function doesn't. I also noticed that label *is*
NULL in my case, so I tried adding that check to
SELinuxSecurityVerify(), and the crash goes away.

I have no idea if this is the correct fix, but it allowed me to
continue my testing of a new (unrelated) feature.
---
 src/security/security_selinux.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
index d06afde..b97ca4c 100644
--- a/src/security/security_selinux.c
+++ b/src/security/security_selinux.c
@@ -871,6 +871,10 @@ SELinuxSecurityVerify(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
                       virDomainDefPtr def)
 {
     const virSecurityLabelDefPtr secdef = &def->seclabel;
+
+    if (def->seclabel.label == NULL)
+        return 0;
+
     if (!STREQ(virSecurityManagerGetModel(mgr), secdef->model)) {
         virSecurityReportError(VIR_ERR_INTERNAL_ERROR,
                                _("security label driver mismatch: "
-- 
1.7.3.4