Re: [PATCH] xsm/flask: improve unknown permission handling

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 27/11/14 15:23, George Dunlap wrote:
> On Tue, Nov 25, 2014 at 6:05 PM, Daniel De Graaf <dgdegra@tycho.nsa.gov> wrote:
>> When an unknown domctl, sysctl, or other operation is encountered in the
>> FLASK security server, use the allow_unknown bit in the security policy
>> (set by running checkpolicy -U allow) to decide if the permission should
>> be allowed or denied.  This allows new operations to be tested without
>> needing to immediately add security checks; however, it is not flexible
>> enough to avoid adding the actual permission checks.  An error message
>> is printed to the hypervisor console when this fallback is encountered.
> Thanks -- I do think as Konrad said however, that when building with
> debug=y, we want the failure to be more obvious.  A crash is probably
> the best thing.
>
> I guess we want something like the following after the printk in
> avc_unknown_permission()?
>
> #ifndef NDEBUG
>     BUG();
> #endif

ASSERT(!"Flask default policy error");

provides rather more information in the panic message, and avoids the
#ifdefs.

~Andrew