[libvirt] [PATCH 2/2] apparmor: don't fail on non-apparmor <seclabel>

[Guido Günther]

Hi, Jim,
On Thu, Feb 09, 2017 at 09:30:16AM -0700, Jim Fehlig wrote:
> Guido Günther wrote:
> > On Fri, Feb 03, 2017 at 10:32:12AM -0700, Jim Fehlig wrote:
> >> If the apparmor security driver is loaded/enabled and domain config
> >> contains a <seclabel> element whose type attribute is not 'apparmor',
> >> starting the domain fails when attempting to label resources such
> >> as tap FDs.
> >>
> >> Many of the apparmor driver entry points attempt to retrieve the
> >> apparmor security label from the domain def, returning failure if
> >> not found. Functions such as AppArmorSetFDLabel fail even though
> >> domain config contains an explicit 'none' secuirty driver, e.g.
> >>
> >>   <seclabel type='none' model='none'/>
> >>
> >> Change the entry points to succeed if the domain config <seclabel>
> >> is not apparmor. This matches the behavior of the selinux driver.
> >>
> >> Signed-off-by: Jim Fehlig <jfehlig at suse.com>
> >> ---
> >>  src/security/security_apparmor.c | 58 ++++++++++++----------------------------
> >>  1 file changed, 17 insertions(+), 41 deletions(-)
> >>
> >> diff --git a/src/security/security_apparmor.c b/src/security/security_apparmor.c
> >> index ad50b08..f871e60 100644
> >> --- a/src/security/security_apparmor.c
> >> +++ b/src/security/security_apparmor.c
> >> @@ -289,10 +289,7 @@ reload_profile(virSecurityManagerPtr mgr,
> >>      virSecurityLabelDefPtr secdef = virDomainDefGetSecurityLabelDef(
> >>                                                  def, SECURITY_APPARMOR_NAME);
> >>  
> >> -    if (!secdef)
> >> -        return rc;
> >> -
> >> -    if (!secdef->relabel)
> >> +    if (!secdef || !secdef->relabel)
> >>          return 0;
> >>  
> >>      if ((profile_name = get_profile_name(def)) == NULL)
> >> @@ -435,7 +432,7 @@ AppArmorGenSecurityLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
> >>                                                  SECURITY_APPARMOR_NAME);
> >>  
> >>      if (!secdef)
> >> -        return -1;
> >> +        return 0;
> >>  
> >>      if ((secdef->type == VIR_DOMAIN_SECLABEL_STATIC) ||
> >>          (secdef->type == VIR_DOMAIN_SECLABEL_NONE))
> >> @@ -495,10 +492,7 @@ AppArmorSetSecurityAllLabel(virSecurityManagerPtr mgr,
> >>  {
> >>      virSecurityLabelDefPtr secdef = virDomainDefGetSecurityLabelDef(def,
> >>                                                      SECURITY_APPARMOR_NAME);
> >> -    if (!secdef)
> >> -        return -1;
> >> -
> >> -    if (!secdef->relabel)
> >> +    if (!secdef || !secdef->relabel)
> >>          return 0;
> >>  
> >>      /* Reload the profile if stdin_path is specified. Note that
> >> @@ -559,12 +553,11 @@ AppArmorReleaseSecurityLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
> >>  {
> >>      virSecurityLabelDefPtr secdef = virDomainDefGetSecurityLabelDef(def,
> >>                                                          SECURITY_APPARMOR_NAME);
> >> -    if (!secdef)
> >> -        return -1;
> >> -
> >> -    VIR_FREE(secdef->model);
> >> -    VIR_FREE(secdef->label);
> >> -    VIR_FREE(secdef->imagelabel);
> >> +    if (secdef) {
> >> +        VIR_FREE(secdef->model);
> >> +        VIR_FREE(secdef->label);
> >> +        VIR_FREE(secdef->imagelabel);\
> > 
> > The trailing slash can be dropped here. The rest of th code looks good
> > to me.
> 
> Opps, thanks for catching that. I've removed it in my local branch.
> 
> Do we need someone else with knowledge of the apparmor driver to review and ACK
> these changes?

It would be great if Jamie could comment as well in case we're
overlooking any details. Otherwise I think we're good to go.

Cheers,
 -- Guido