[libvirt] [PATCH 1/2] selinux: load and free selinux active file contexts configuration database

[Guannan Ren]

On 10/15/2012 06:40 PM, Martin Kletzander wrote:
> On 10/15/2012 12:22 PM, Daniel P. Berrange wrote:
>> On Mon, Oct 15, 2012 at 03:12:45PM +0800, Guannan Ren wrote:
>>> If we use matchpathcon() to look up selinux context for specific pathname,
>>> it'd better actively load file contexts database by matchpathcon_init()
>>> and free memory when finished using matchpathcon by matchpathcon_fini().
>>> ---
>>>   src/security/security_selinux.c | 8 ++++++++
>>>   1 file changed, 8 insertions(+)
>>>
>>> diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
>>> index 10135ed..b278e2c 100644
>>> --- a/src/security/security_selinux.c
>>> +++ b/src/security/security_selinux.c
>>> @@ -667,6 +667,10 @@ virSecuritySELinuxSecurityDriverProbe(const char *virtDriver)
>>>   static int
>>>   virSecuritySELinuxSecurityDriverOpen(virSecurityManagerPtr mgr)
>>>   {
>>> +#ifndef HAVE_SELINUX_LABEL_H
>>> +    if (matchpathcon_init(NULL) < 0)
>>> +        VIR_WARN("cannot load selinux active file contexts configuration");
>>> +#endif
>>>       return virSecuritySELinuxInitialize(mgr);
>>>   }
>>>   
>>> @@ -685,6 +689,10 @@ virSecuritySELinuxSecurityDriverClose(virSecurityManagerPtr mgr)
>>>       VIR_FREE(data->file_context);
>>>       VIR_FREE(data->content_context);
>>>   
>>> +#ifndef HAVE_SELINUX_LABEL_H
>>> +    if (matchpathcon_fini() < 0)
>>> +        VIR_WARN("cannot free allocated memory for selinux");
>>> +#endif
>>>       return 0;
>>>   }
>> I'm not convinced this is safe, because the security drivers can be
>> opened multiple times, eg LXC and QEMU, and this is changing the global
>> static state of the SELinux library.
>>
> I didn't think the driver is opened for every other driver used.  In
> this case the initialization of the matchpathcon should be dealt with in
> some other way.  Or can't we open the security driver only once?
>
> @Guannan: is there a problem this fixes?  How come it worked without the
> init before?
>
> Martin
>

    No, there is no a bug/problem to fix, the patch just actively 
initializes
    the active context configuration database.
    If we don't do this, the matchpathcon will do it instead.
    I am going to add them in a better way later.
    This patch has nothing to do with the 2/2 patch.

    Guannan