Re: [TOMOYO #15 0/8] TOMOYO Linux

Pavel Machek
2009-02-25T19:43:54Z

On Mon 2009-02-23 16:37:02, Toshiharu Harada wrote:
> Pavel Machek wrote:
>> On Sun 2009-02-22 23:27:34, Tetsuo Handa wrote:
>>> Pavel Machek wrote:
>>>> On Thu 2009-02-12 16:34:16, James Morris wrote:
>>>>> On Thu, 5 Feb 2009, Kentaro Takeda wrote:
>>>>>
>>>>>> TOMOYO Linux is a name-based MAC extension (LSM module) for the Linux kernel.
>>>>>>
>>>>> Applied to
>>>>> git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6#next
>>>>>
>>>> Does that mean tomoyo is scheduled for 2.6.30?
>>>>
>>> TOMOYO is already in linux-next tree and ready to go into 2.6.30 .
>>
>> Last time I looked it included script parser and some
>> interpretter... Was that solved?

>
> Are you talking about the interface between
> userland and kernel regarding string data?

Yes. maybe ioctl() is worse, but I don't think c-like language parser
in kernel is acceptable.

> Linus once said in a Smack thread (http://lkml.org/lkml/2007/11/5/129)
>>> On Sun, Nov 04, 2007 at 12:28:48PM +0000, Pavel Machek wrote:
>>> > Can we avoid string parsers in the kernel?
>>>
>>> Ok, Could someone suggest a better idea please ?.
>>
>> I personally think string parsers are *much* better than the
>> alternatives (which basically boil down to nasty binary interfaces)
>>
>>> I thought about packing the rules in a structure and sending
>>> it over an ioctl() command. Is this applicable ?
>>
>> That's *MUCH* worse.
>>
>> Strings are nice. They aren't that complex, and as long as it's not a
>> performance-critical area, there are basically no downsides.
>>
>> Binary structures and ioctl's are *much* worse. They are totally
>> undebuggable with generic tools (think "echo" or "strace"), and they
>> are a total nightmare to parse across architectures and pointer sizes.
>>
>> So the rule should be: always use strings if at all possible and relevant.
>> If the data is fundamentally binary, it shouldn't be re-coded to ascii
>> (no real advantage), but if the data is "stringish", and there aren't
>> big performance issues, then keep it as strings.
>
> Admiring your concern, I would like to follow the above directions.
>
> Best regards,
> Toshiharu Harada

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