Re: [ LIBSEMANAGE ] Runtime control over preservebools argument

[Daniel J Walsh <dwalsh@redhat.com>]

Joshua Brindle wrote:
> Ivan Gyurdiev wrote:
>> Stephen Smalley wrote:
>>
>>> On Fri, 2005-11-04 at 09:22 -0500, Ivan Gyurdiev wrote:
>>>  
>>>
>>>> So, how do I specify that this is not a transient change, and I 
>>>> want my booleans loaded into policy immediately?
>>>>     
>>>
>>>
>>> Ah, I see - setsebool -P wants to both update the saved settings and
>>> load the result rather than preserving current settings.  So it wants
>>> libsemanage to call load_policy with -b, unlike semodule.  Options are:
>>> - add a semanage interface to set a property on the handle to control
>>> whether booleans are preserved or not (by altering the args to
>>> load_policy for that handle), similar to the existing interface for
>>> controlling whether reloads are performed, or
>>>   
>>
>> Editing an argument string for programs in C is... probably one of 
>> the most uncool patches I've ever written.
>> I guess the end justifies the means...
>>
>> Should pass valgrind, and work when called repeatedly with values 0 
>> or 1. Maybe the reload=0 case is a bit wrong - argument string cannot 
>> contain "-b" anywhere.
>>
>> I also fixed the memory leak in setsebool - see other patch (which 
>> should be applied first).
>>
>> Now booleans update correctly (minus migration issues - see other mail).
>> Next: make them update in less than 10 seconds :)
>>
>>
> <snip>
>
>> +    if (do_reload) {
>> +        char* prev_args = conf->load_policy->args;
>> +        int len = (prev_args == NULL)? 0: strlen(prev_args);
>> +        char* ptr = (char*) realloc(prev_args, len + 4);
>> +
>> +        if (!ptr) {
>> +            ERR(sh, "out of memory, could not configure "
>> +                "boolean reload");
>> +            return STATUS_ERR;
>> +        }
>> +        strcpy(ptr + len, " -b");
>> +        conf->load_policy->args = ptr;
>> +
>> +    } else {
>> +        char* ptr = conf->load_policy->args;
>> +
>> +        while(*ptr++) {
>> +            if (!strcmp(ptr, "-b")) {
>> +                *ptr++ = ' ';   
>> +                *ptr++ = ' ';
>> +            }
>> +        }
>> +    }
>> +    return STATUS_SUCCESS;
>> +}
>> +
> I think you are doing this in the wrong place. Rather than mangling 
> the argument string every time this function is called you should just 
> add something to the handle that indicates whether or not to preserve 
> booleans, and do this at load time.
>
> However, I don't know if this is the right approach anyway. If someone 
> sets a boolean without -P , foo, and then sets another boolean with -P 
> you will revert foo when loading the new policy.
>
> IMHO while we will need to regenerate the policy we should not load it 
> and instead just set the runtime state. This will work for the common 
> case but there is something of a corner case where the above scenerio 
> happens and a module is also inserted in the same transaction, not 
> sure how to handle that one.
>
> Joshua

I agree setsebool should not be loading policy.

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