Linux-kernel mailing list archive 1999-20,: Re: More capabilities stuff...

# Re: More capabilities stuff...

Alexander Kjeldaas (astor@fast.no)
Tue, 18 May 1999 10:02:34 +0200

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On Sun, May 16, 1999 at 06:34:54AM -0400, John Wojtowicz wrote:
>
> >I suppose you intend to turn normal user abilities into default
> >capabilities. (the ability to write to a writable file...)
>

> That by definition isn't a privilege. If the file is writable by
> that user, then the privilege for DAC write permission override
> isn't needed to write it. However, the uid check should be short
> circuited by the check DAC write permission override.

> I would believe that eventually you would want to convert all uid 0
> checks in the kernel to capabilities checks. Then if you've
> compiled the kernel with out capabilities enabled, you'd dummy up
> the effective, permitted and inheritable sets for all uid 0
> processes to have ALL privileges in it, and all other normal users
> have NONE in their process capability sets. If it is enabled then
> you perform the normal capabilities calculations whenever a process
> is exec()'ed. Is this the plan Linus?

The above is generally what is happening in 2.2 - there are no checks
for uid==0. In addition to the above, there is some capabilities
conversions during set*id from/to uid 0.

astor

    --
     Alexander Kjeldaas, Fast Search & Transfer, Trondheim, Norway

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