Setup:

http://support.apple.com/kb/TA20987 explains how to configure loginwindow
to do Kerberos. After you have done so and it works, you can add this as
aklog:CELLNAME,privileged

after loginwindow:success and before HomeDirMechanism:login,privileged

e.g.
change
<string>loginwindow:success</string>
<string>HomeDirMechanism:login,privileged</string>

to

<string>loginwindow:success</string>
<string>aklog:andrew.cmu.edu,privileged</string>
<string>HomeDirMechanism:login,privileged</string>

in the system.login.console section of /etc/authorization.

The following is from Apple's ROT13 plugin:

Note: The preferred way to modify the /etc/authorization file is to use
the Authorization APIs in <Security/AuthorizationDB.h>. This is always
how it should be done in shipping products, as there may have been other
modifications to the /etc/authorization file. A code snippet to do this
is:

#include <CoreFoundation/CoreFoundation.h>
#include <Security/AuthorizationDB.h>

#define LOGIN_RIGHT "system.login.console"

int main(int argc, char *argv[])
{
    CFDictionaryRef login_dict;
    OSStatus status;
    AuthorizationRef authRef;

    status = AuthorizationCreate(NULL, NULL, 0, &authRef);
    if (status) exit(1);

    status = AuthorizationRightGet(LOGIN_RIGHT, &login_dict);
    if (status) exit(1);

    CFArrayRef arrayRef;
    if (!CFDictionaryGetValueIfPresent(login_dict, CFSTR("mechanisms"),
    	&arrayRef))
        exit(1);

    CFMutableArrayRef newMechanisms = CFArrayCreateMutableCopy(NULL, 0,
    	arrayRef);
    if (!newMechanisms)
        exit(1);

    CFIndex index = CFArrayGetFirstIndexOfValue(newMechanisms,
    	CFRangeMake(0, CFArrayGetCount(newMechanisms)), CFSTR("authinternal"));

    if (index == -1)
        exit(1);

    CFArraySetValueAtIndex(newMechanisms, index, CFSTR("newmech"));

    CFMutableDictionaryRef new_login_dict 
    	= CFDictionaryCreateMutableCopy(NULL, 0, login_dict);

    CFDictionarySetValue(new_login_dict, CFSTR("mechanisms"), newMechanisms);

    status = AuthorizationRightSet(authRef, LOGIN_RIGHT, new_login_dict,
    	NULL, NULL, NULL);

    if (status) exit(1);
}
