Re: [PATCH] Exporting capability code/name pairs

From: KaiGai Kohei
Date: Thu Jan 03 2008 - 20:56:53 EST


> There is also the issue of compiled code which explicitly raises and
> lowers capabilities around critical code sections (ie., as they were
> intended to be used) is also not well served by this change.
>
> That is, unless the code was compiled with things like CAP_MAC_ADMIN
> being #define'd then it won't be able to do things like cap_set_flag()
> appropriately.

A new function will be necessary, like:
cap_value_t cap_get_value_by_name(const char *cap_name);

If a program tries to use specific capabilities explicitly, it can
apply pre-defined capability code like CAP_MAC_ADMIN.

However, when we implement a program which can deal with arbitrary
capabilities, it should obtain codes of them dynamically, because
it enables to work itself on the feature kernel.

Thanks,

> Cheers
>
> Andrew
>
> KaiGai Kohei wrote:
>> Andrew Morgan wrote:
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>>> KaiGai Kohei wrote:
>>>> Remaining issues:
>>>> - We have to mount securityfs explicitly, or use /etc/fstab.
>>>> It can cause a matter when we want to use this feature on
>>>> very early phase on boot. (like /sbin/init)
>>> I'm not altogether clear how you intend this to work.
>>>
>>> Are you saying that some future version of libcap will require that
>>> securityfs be mounted before it (libcap) will work?
>> Yes, but implementing this feature on securityfs might be not good
>> idea as as James said. If this feature is on procfs or sysfs, it is
>> not necessary to mount securityfs explicitly.
>>
>> Thanks,
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